Ashrae Refcx Guide

Posted originally, 12/5/13 Re-posted with errata dated 1/16/14 incorporated, 1/16/14

The Essential Guide for Commissioning Refrigeration Systems

Because deficiencies in system design found at start-up are not easily resolved, maintenance managers or operators may deal with unnecessary shortcomings and expenses over the life of the facility. Commissioning helps project teams avoid these “surprises” by establishing a consistent, stepwise process that helps “get it right the first time.” The commissioning process starts with the initial planning and design and continues through construction, installation, start-up, and the first year of system operation. Commissioning also sets the stage for ongoing servicing and maintenance of performance. The result is refrigeration systems that are easier and less expensive to install and maintain, with lower energy costs, minimized liabilities from refrigeration system leaks, and reduced loss of refrigerated product due to system failures or unreliable performance. Using this Guide will help achieve cost-effective and cost-efficient refrigeration systems for new projects, expansions, remodels, and existing systems that simply need a tune-up.

Refrigeration Commissioning Guide for Commercial and Industrial Systems

The first of its kind, Refrigeration Commissioning Guide for Commercial and Industrial Systems provides guidance to owners and managers of commercial and industrial facilities that use refrigeration systems to help ensure that project requirements are met and owners’ expectations are achieved. For commercial facility owners and managers, this means improved profitability through lower operating and service costs as well as reduced product loss.

Refrigeration Commissioning Guide for Commercial and Industrial Systems

Commissioning Refrigeration Systems in ISBN 978-1-936504-53-4

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• Food Retail and Convenience Stores • Small Retail Stores • Food and Beverage Facilities • Food Distribution Centers • Industrial Plant Applications

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This publication was developed under ASHRAE’s Special Publication procedures and is not a consensus document. It was developed under the auspices of ASHRAE Special Project 137 and was supported with funding from U.S. Department of Energy through National Renewable Energy Laboratory subcontract #AGN-1-11923.

Cognizant Committee: Refrigeration Committee

Refrigeration Commissioning Guide Project Committee Richard Royal—Chair Wal-Mart Stores, Inc. Bryan Beitler Source Refrigeration and HVAC

Doug Scott VaCom Technologies

Jon Edmonds Edmonds Engineering Co.

Scott Smith Hillphoenix

Timothy Gwyn DC Engineering, PC

Paul Torcellini National Renewable Energy Laboratory

Larry Meeker Target

Robert Uhl Safeway, Inc.

Scott Moore PECI

Jim Vannan Winn-Dixie

Caleb Nelson CTA

Lilas Pratt ASHRAE Staff Liaison Bert Etheredge ASHRAE Staff Support

Updates/errata for this publication will be posted on the ASHRAE website at www.ashrae.org/publicationupdates.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

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ISBN 978-1-936504-53-4 © 2013 ASHRAE. All rights reserved. 1791 Tullie Circle, NE · Atlanta, GA 30329 · www.ashrae.org Cover design by Laura Haass ASHRAE is a registered trademark in the U.S. Patent and Trademark Office, owned by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. ASHRAE has compiled this publication with care, but ASHRAE has not investigated, and ASHRAE expressly disclaims any duty to investigate, any product, service, process, procedure, design, or the like that may be described herein. The appearance of any technical data or editorial material in this publication does not constitute endorsement, warranty, or guaranty by ASHRAE of any product, service, process, procedure, design, or the like. ASHRAE does not warrant that the information in the publication is free of errors, and ASHRAE does not necessarily agree with any statement or opinion in this publication. The entire risk of the use of any information in this publication is assumed by the user. While supported by the U.S. Department of Energy with the National Renewable Energy Laboratory, neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof and shall not be used for advertising or product endorsement purposes. Except for rights reserved by the U.S. Government, no part of this book may be reproduced without permission in writing from ASHRAE, except by a reviewer who may quote brief passages or reproduce illustrations in a review with appropriate credit; nor may any part of this book be reproduced, stored in a retrieval system, or transmitted in any way or by any means—electronic, photocopying, recording, or other—without permission in writing from ASHRAE. Requests for permission should be submitted at www.ashrae.org/permissions. Library of Congress Cataloging-in-Publication Data Refrigeration commissioning guide for commercial and industrial systems. pages cm Includes bibliographical references and index. Summary: "Provides how-to guidance for commissioning custom-engineered refrigeration systems in commercial and industrial facilities to improve and supplement existing design, construction, and operational practices"-- Provided by publisher. ISBN 978-1-936504-53-4 (softcover : alk. paper) 1. Refrigeration and refrigerating machinery--Industrial applications. 2. Refrigerators--Installation. 3. Commercial buildings-Equipment and supplies--Installation--Planning. I. American Society of Heating, Refrigerating and Air-Conditioning Engineers. TP492.R3785 2013 621.5'6--dc23 2013041539

ASHRAE STAFF

SPECIAL PUBLICATIONS Mark S. Owen, Editor/Group Manager of Handbook and Special Publications

PUBLISHING SERVICES

PUBLISHER

Cindy Sheffield Michaels, Managing Editor James Madison Walker, Associate Editor Roberta Hirschbuehler, Assistant Editor Sarah Boyle, Assistant Editor Michshell Phillips, Editorial Coordinator David Soltis, Group Manager of Publishing Services and Electronic Communications Jayne Jackson, Publication Traffic Administrator Tracy Becker, Graphics Specialist W. Stephen Comstock

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Contents

Preface

The Business Case for Commissioning: A Message to Owners . . . vii

Acknowledgments

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Chapter 1

Introduction The Need for Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 How to Use this Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Chapter 2

Commissioning during Planning and Design Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Forming the Commissioning Team . . . . . . . . . . . . . . . . . . . . . . . 13 Developing the Owner’s Project Requirements (OPR) . . . . . . . . 15 Managing the Issues Log . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Developing the Commissioning Plan . . . . . . . . . . . . . . . . . . . . . 25 Developing the Basis of Design (BoD) . . . . . . . . . . . . . . . . . . . . 28 Requirements for Construction Documents (CDs) . . . . . . . . . . . 32 Deliverables and Acceptance . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Chapter 3

Commissioning during Construction and Installation Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Installation Planning and Scope of Work . . . . . . . . . . . . . . . . . . Prefunctional Testing and Verification . . . . . . . . . . . . . . . . . . . . Construction and Installation Details. . . . . . . . . . . . . . . . . . . . . . Final Installation Commissioning and Review. . . . . . . . . . . . . . .

Chapter 4

37 41 45 50 55

Commissioning during Start-Up and First-Year Operation Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Commissioning Activities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Start-Up Report and Handoff to Owner. . . . . . . . . . . . . . . . . . . . 63 Activities in the First Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 First-Year Final Report and Acceptance. . . . . . . . . . . . . . . . . . . 68

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Appendix A

Roles and Responsibilities Matrix. . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Appendix B

Example Commissioning Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Appendix C

Example Acceptance Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Appendix D

Technical Procedures 1 2 3 4 5 6 7 8 9 10

vi

Verifying Control Functions. . . . . . . . . . . . . . . . . . . . . . . . . . 89 Verifying Refrigeration System Capacity . . . . . . . . . . . . . . . 92 Evaluating Part-Load Operation . . . . . . . . . . . . . . . . . . . . . . 96 Checking Refrigerant Temperatures and Pressures and Evaluating Setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Verifying Operation of Alarms . . . . . . . . . . . . . . . . . . . . . . . 101 Evaluating Refrigerant Piping . . . . . . . . . . . . . . . . . . . . . . . 104 Verifying Anti-Sweat Heater Control Operation . . . . . . . . . 107 Verifying Defrost Adequacy and Defrost Control Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Minimizing Air Infiltration of Boxes and Cases . . . . . . . . . . 112 Evaluating the Use of Energy-Saving Features . . . . . . . . . 113

Glossary

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

References

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

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Preface The Business Case for Commissioning: A Message to Owners

Refrigeration Commissioning Guide for Commercial and Industrial Systems provides value to owners and managers of commercial and industrial facilities that use refrigeration systems by ensuring that project requirements are met and owners’ expectations are achieved. Refrigeration systems account for a significant portion of commercial building energy use and are often the largest energy end use in food and beverage facilities. A U.S. Department of Energy (DOE) study estimates commercial refrigeration uses 1.23 quads (1.23 × 1015 Btu) (1.30 EJ) per year, which is approximately 7% of commercial building energy use. Nearly 70% of this commercial refrigeration use consists of supermarkets and other customdesigned refrigeration systems (DOE 2009). Supermarkets are the largest example: a U.S. Environmental Protection Agency (EPA) study estimates that supermarkets typically use approximately 3,000,000 kWh of electricity per year, with 60% of that energy use attributed to refrigeration (EPA 2007). Portland Energy Conservation, Inc. (PECI) predicts that commissioning in existing grocery stores would result in 7% to 25% energy savings per year (PECI 2010). Based on these estimates, this commissioning guide, if widely adopted, would lead to substantial U.S. national energy savings. Custom refrigeration systems are complex and individually designed for each facility. Deficiencies in the system design found at start-up are not easily resolved and, as a result, maintenance managers or operators deal with unnecessary shortcomings and expenses over the life of the facility. The value of commissioning is to establish a consistent stepwise process that helps “get it right the first time,” resulting in refrigeration systems that “work right” and minimize maintenance and energy costs. Thousands of refrigeration systems are installed every year in facilities ranging from convenience stores to large, sophisticated frozen food distribution centers. Properly commissioned systems reduce energy costs, are easier to maintain, help minimize liabilities from refrigeration leaks, and reduce loss of product due to system failures or unreliable performance. Commissioning of refrigeration systems is currently uncommon. One reason is the belief that commissioning results in added cost and time without ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

sufficient or measurable value. Certainly, commissioning is an investment, but it provides significant financial value in several ways. First, systems operate more reliably with lower maintenance cost and lower energy cost when commissioning is applied as described in this Guide. Second, incorporating commissioning can reduce first cost through improved understanding of system performance and lead to better equipment design and installation methods. Using this Guide will help achieve cost-effective and cost-efficient refrigeration systems for new projects, expansions, remodels, and existing systems that simply need a tune-up. For commercial facility owners and managers, this means improved profitability through lower operating and service costs as well as reduced product loss. For industrial plants, this means improved “up time” and improved labor productivity in addition to reduced operating cost. The commissioning process is holistic and considers life-cycle performance, including the long-term operating (utilities and servicing) costs of the refrigeration system. Commissioning is not another term for start-up. The commissioning process starts with the initial planning and design and continues through construction, installation, start-up, and the first year of system operation. Commissioning also sets the stage for ongoing servicing and maintenance of performance. This Guide provides the process and methods to help achieve these desired results: expected performance and reliability with the lowest life-cycle cost.

viii

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Acknowledgments

Refrigeration Commissioning Guide for Commercial and Institutional Systems was developed to provide guidance to refrigeration system owners, project/design managers, and refrigeration system service providers. This Guide is the result of the collaborative effort of dedicated professionals who unselfishly volunteered countless hours to give refrigeration system owners and the refrigeration industry consistent validation processes that can be used to bring order to the unorderly. The primary authors were the members of ASHRAE Special Project Committee 137 and provided the expertise and experience necessary to develop the document. They represented manufacturers, contractors, and end users of refrigeration systems. The project would not have been possible without the financial support of the U.S. Department of Energy (DOE) and National Renewable Energy Laboratory (NREL) as well as the invaluable support of ASHRAE. In addition, DOE’s Better Buildings Alliance provided the project committee with the technical services of Rebecca Legett and Robert Zogg of Navigant Consulting, Inc. I would also like to thank Paul Torcellini of NREL for his support and help with the development of the document. I would also like to personally thank all the members of the project committee for their diligence, creativity, persistence, and willingness to take time to support the development and review of this Guide. They worked extremely hard to put together practical and fundamental information covering the aspects of commissioning applicable to a holistic approach. Their expertise and differing views greatly enriched this Guide. The authors brought many decades of experience, success, and failure to the text to achieve a significant milestone for the refrigeration system owner and the refrigeration system industry. I appreciate the patience of the committee members’ families during the development process, and I gratefully acknowledge the support of the committee members’ employers, including CTA; DC Engineering, PC; Edmonds Engineering Company; Hillphoenix; National Renewable Energy Laboratory; PECI; Safeway, Inc.; Source Refrigeration and HVAC; Target ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Corporation; VaCom Technologies; Wal-Mart Stores, Inc; and Winn-Dixie Stores, Inc. Additional thanks go to the ASHRAE staff, including Lilas Pratt and Bert Etheredge, whose direction and guidance were invaluable and whose organizational skills and dedication helped keep the project committee on track. Richard Royal Chair, ASHRAE Special Project Committee 137

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1 Introduction

Refrigeration Commissioning Guide for Commercial and Industrial Systems provides user-friendly, how-to guidance for commissioning of customengineered refrigeration systems in commercial and industrial facilities. The intended audience of this Guide includes system owners, architects, design engineers, contractors, facility managers, and maintenance service providers, as well providers of commissioning services. Commissioning is a process for ensuring that a facility or system is designed and operated as intended. Commissioning helps achieve larger goals of sustainable design and operations, life-cycle cost-effectiveness, efficient use of capital, minimizing overall maintenance costs and utility costs, long equipment life and reliability, and meeting performance expectations. ASHRAE addresses commissioning in two other publications: ASHRAE Guideline 0, The Commissioning Process (2005), describes a general commissioning process applicable to any facility or system and ASHRAE Guideline 1.1, HVAC&R Technical Requirements for the Commissioning Process (2007), addresses how the commissioning process is applied to heating, ventilating, and air-conditioning (HVAC) systems, with some discussion of refrigeration systems. While Guideline 0 and Guideline 1.1 provide useful information, they do not readily address the needs of refrigeration systems. Refrigerated facilities are both numerous and among the most energy-intense commercial buildings. Refrigeration Commissioning Guide for Commercial and Industrial Systems builds on the concepts and process outlined in Guideline 0, providing specific methods and approaches to achieve comprehensive commissioning of commercial and industrial refrigeration systems. Development of this Guide began after multiple discussions within ASHRAE concerning the value and need for such a publication and after consideration of many factors, such as the customized nature of refrigeration systems as contrasted to packaged HVAC systems and the typical methods of designing and contracting for refrigeration work. These are two of the factors that have resulted in very limited commissioning of refrigeration systems in current practice. The value of commissioning is clear to those designing and operating for improved sustainability in refrigerated facilities. To meet the ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

apparent need and demonstrate the value of commissioning in the marketplace, it became clear that refrigeration experts should define the needs, determine the appropriate processes, and develop a guide specifically tailored for the commissioning of refrigeration systems.

THE NEED FOR COMMISSIONING

2

Refrigeration systems for most commercial and industrial facilities are custom-engineered for each application, with individual equipment selected and matched to meet project needs and designer preferences. In contrast, a rooftop cooling unit or a packaged water chiller is factory built as a package subject to standards and certification as a combined system, with performance and specifications fully described and catalogued. While factory packages still need commissioning, the more customized nature of refrigeration is an important factor in defining how refrigeration commissioning will be accomplished. Refrigeration system designers choose the type of refrigerant, control valves, compressor technology, method of oil management, capacity control measures, type of condensing (air or water cooled), and control system design and strategies. Supermarket store-planners determine which display cases will be used, what configuration will be laid out, and what merchandise will be in the cases. Temperature, load, and evaporator layout can be completely unique from project to project, requiring that compressors, condensers, evaporators, valves, and receivers be designed specifically for each project. Various control system providers and programmers contribute their products and services to the completed system, which adds another layer of customization. There are not only numerous manufacturers of compressors, condensers, cases, coils, and controllers but also numerous owners and contractors with their unique specifications—resulting in the possibility for infinite variations. As with most construction projects, speed to market is critical. While many companies have well-established specifications and criteria, limited design time can make design coordination difficult. For example, to start pursuing permits for a new facility, a preliminary refrigeration design may be completed early in the process. That design is then distributed for bidding and construction several months later. When the equipment is received directly from the providers, the contractor must integrate everything on site. This process can result in the design’s intent being lost. The commissioning process can help to preserve that intent for manufacturers and programmers. Historically, the design and construction of commercial and industrial refrigeration systems have not followed the approach where the architect is responsible for all design engineers and a general contractor is responsible for all contractors. Refrigeration design has typically been separate from the architect’s responsibility. The entire refrigeration scope may be assumed by a design-build contractor responsible for engineering the systems, providing the equipment, and performing the installation. The owner may have multiple design, equipment, and installation providers, all under separate contracts. Owners with multiple facilities may establish detailed criteria, design the refrigeration systems in house, rely on an original equipment manufacturer (OEM), or use a design consultant with refrigeration specialization. Because much of the commercial refrigeration business involves repetitive construction (e.g., multifacility operations), refrigeration design often evolves from one project to the next following a general criteria or relies on the experience

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1 ~ Introduction

ENERGY SAVINGS FROM COMMISSIONING AS RELATED TO RETAIL SALES DOLLARS—A CASE STUDY Background: A study of several recently opened stores owned by a large supermarket chain revealed that each store had major shortcomings in the operation of its refrigeration and control systems. The chain has a large development department that includes architects, engineers, project managers (PMs), construction managers, and others, so the store designs were based on a well-developed set of specifications and criteria drawings and should have all been operating the same way. Further investigation revealed that the contractors for the subject stores had not followed the plans and specifications. Problem: One specific store in California had been open for more than a year at the time of the study. The store had been designed to meet California Title 24 standards (CA 2013a, 2013b) and the store design had been evaluated by a leading engineering firm using energy modeling software. The modeling had shown that with all efficiency measures working properly the store energy use would be 2,800,000 kWh/year. However, the actual energy use for this store during the first year of operation was 3,500,000 kWh/year. Lessons Learned: The Energy Management team developed and implemented a strategy to retrocommission the store systems. The result was a reduction in annual energy usage of 750,000 kWh and annual cost savings of $90,000, bringing the system more in line with the expectations generated by the model (see the figure). Support for changes to address this issue at other stores and in future new construction required attention from retail management. But, the value of these savings is difficult to grasp when the focus is on sales dollars. Translating the savings into equivalent sales dollars shows that the average supermarket would have to sell approximately $4,500,000 in groceries (or about 10 weeks’ worth of sales) in order to make up the dollar value of 750,000 kWh in energy savings. Additional savings would also result from reduced maintenance and/or a possible increase in sales from improved conditions in the store. The magnitude of the savings demonstrated the cost-effectiveness of a new construction commissioning process that clearly defines expectations and verifies that equipment and controls are performing according to expectations. Subsequently, other stores in the chain also experienced savings ranging from 4% to 24% after similar retrocommissioning. Commissioning should start before design so that expectations are met at the start of operation rather than errors being discovered and having to be fixed only after excessive energy consumption is realized.

Energy Usage in Kilowatt-Hours as Designed, Before and After Commissioning

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

of “what works” and ensures product temperature requirements are met. Design practice, equipment sizing, and performance expectations are highly dependent on the experience of designers and contractors. Most refrigeration components (unlike HVAC equipment) are not certified to a rating standard, and generally equipment catalogs do not reference a test standard. Rules of thumb and experience factors are inherent throughout the design, construction, and operation of systems and are related to the built-up nature of nearly all refrigeration systems and related control systems. Several retail chains have in recent years changed from reliance on vendor- or contractor-provided engineering to employing a refrigeration design consultant and incorporating refrigeration with the other mechanical engineering responsibilities (e.g., HVAC, plumbing). This approach adds refrigeration to the traditional mechanical, electrical, plumbing (MEP) design consultants and creates a mechanical, electrical, plumbing, and refrigeration (MEPR) team responsible to the owner and architect. In addition, it has become more prevalent for the general contractor to assume responsibility for the refrigeration subcontractor. To address the fragmentation of the process, commissioning seeks to provide a common thread with the purpose of creating highperformance refrigeration systems that meet specifications as well as minimize energy consumption while increasing reliability and maintainability.

PURPOSE AND SCOPE

4

The purpose of this Guide is to outline a commissioning process for refrigeration systems that can be readily adopted by a wide range of owners, designers, and contractors of commercial and industrial refrigeration systems in the United States and globally. The Guide is designed to start at project conception and extend through the first year of operation. Moreover, it also establishes a basis for a continuous improvement process lasting throughout the life of the facility. This Guide is intended to improve and supplement existing design, construction, and operational practices. Since most companies have successfully refined their practices to achieve on-time and on-budget projects, commissioning must be carefully considered and adopted such that the existing responsibilities for design, supplier compliance, and contract completion are not diminished. Table 1-1 shows the people involved in commissioning a project and describes their roles or interests in the process. A key concept in the Guide is that the commissioning work is a process or function that entails multiple entities and individuals over the course of a project—commissioning is not simply the work of a single commissioning authority (CxA). The Guide is designed to be flexible and to acknowledge the varied methods of designing and contracting refrigeration work across industry segments and from company to company. The Guide can be easily adopted in part or in whole, without assuming one contracting method over another. Users of the Guide will need to determine the elements that are appropriate to their projects, interests, and capabilities and define the responsibilities within available company and project team resources. This Guide does not attempt to comprehensively address system design, detailed construction specifications, construction methods, or detailed routine start-up procedures (e.g., oil and refrigerant charging methods), and it does not include safety topics.

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1 ~ Introduction

Table 1-1 Potential Participants in the Commissioning Process

Owner

In general, “owner” relates to “who is paying the bills” and has the greatest interest in life-cycle cost and getting value from the system. Examples include the following: • Individual owner of business who may be very involved with project specifics, such as an independent store or specialty food manufacturer owner • Owner not directly involved with project specifics, such as a property investment/management firm funding an expansion of a refrigerated warehouse • Large company or chain where the owner is represented by an employee or a third-party agent

Tenant

The tenant directly or indirectly pays for operating costs. Some projects are built to suit the needs for a particular tenant based on medium- or long-term arrangements.

Engineering Team

Refrigeration design engineer(s), including the following: • Consulting refrigeration engineer • Engineer(s) for design-build contractor • Refrigeration equipment supplier(s) • Individual acting as Engineer of Record, as required Other engineers and disciplines, including the following: • Thermal envelope designer, in the case of a refrigerated warehouse • Control system designer, vendor, or contractor • Electrical engineer, related to refrigeration equipment and controls integration with other systems

Contractors

Refrigeration contractor(s), including the following: • One contractor providing and installing refrigeration equipment and controls • A separate controls contractor • A separate contractor for walk-ins or thermal envelope and doors

Safety and Code Consultants

Depending on the type of project, the location, and the type of equipment, additional consultants or specialists may be responsible for safety concerns and complying with safety regulations. Special concerns arise from certain system types (such as ammonia systems).

Commissioning services may be provided by the following: • Independent third-party commissioning consultants who manage and coordinate the overall commissioning process (see the sidebar “Best Practices for a Commissioning Authority: Commissioning Independence, Perspective, and Understanding” in Chapter 2 of this Guide) Service • A member of the design team Providers • The design-build refrigeration contractor • Technical commissioning specialists who provide third-party testing and verification to implement the technical aspects of commissioning Operations and maintenance personnel are responsible for keeping the equipment operating and maintaining temperature limits. They may be in house or outside contractors and may be different after the warranty period. The operations interests for a facility can vary widely: Operations and • Chain supermarkets often have an operations division that prefers a standardized view of refrigeration focused on reliability, maintainability, and energy performance. Maintenance Personnel • An industrial project may require close coordination by plant operators, maintenance personnel, and production staff, particularly on an existing facility expansion. • For a new facility, the on-site operations staff may be involved late in the process, only as they are hired or assigned to the location.

Energy and Sustainability Consultants

Various parties may be involved with energy efficiency and sustainability, including the following: • Corporate departments measuring facility performance with metrics such as energy, water, and sustainability • Energy efficiency consultant engaged by owner • Utility and related program consultants for incentives and design assistance programs • Labeling and certification program consultants (e.g., bEQ, LEED®, Green Globes, ENERGY STAR®)

Other

Projects with new or special equipment, systems, or technology may include an associated representative to assist with design integration and commissioning. An Information Technology representative may be necessary to support data communications and management of information resources required to meet commissioning objectives.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

The Guide emphasizes refrigeration systems commonly used in commercial and smaller industrial facilities (e.g., retail food stores, halocarbon systems for warehouses, and small food facilities, etc.). While the commissioning processes outlined will also apply to commissioning of large industrial ammonia-based refrigeration systems and large built-up central compressor plants, specific technical procedures related to large industrial and ammonia systems are not addressed in this Guide. The phases of commissioning described in Refrigeration Commissioning Guide for Commercial and Industrial Systems are, in order: 1. Planning and Design 2. Construction and Installation 3. Start-Up and First-Year Operation This Guide is intended to be used within a variety of construction and contracting arrangements, including the following: • Design-build projects by refrigeration contractors • Owner-designed projects installed by a refrigeration contractor • Projects designed by the owner’s consultant and installed by a refrigeration contractor This Guide is expected to be used frequently by design-build contractors, who manage the commissioning process largely on the owner’s behalf and/or execute the technical procedures. While the benefit of an independent thirdparty perspective may not be achieved with this approach, this reflects the reality of the industry and how many commercial and industrial projects are contracted as well as the fact that a great deal of the relevant expertise resides with design-build contractors. For this reason, the Guide is designed to accommodate a “self-managed” method as well as apply to commissioning activities performed by consultants and independent third parties. Additional perspective on third-party commissioning authorities is provided in the Chapter 2 sidebar “Best Practices for a Commissioning Authority: Independence, Perspective, and Understanding.” This Guide is designed to address the characteristics of typical refrigeration applications and systems, including the following: • Refrigeration systems must perform (maintain temperatures) at all hours of operation, in contrast to air-conditioning systems, which may be designed to meet temperatures a certain percentage of hours. The consequences of failing to maintain temperatures are therefore more problematic in refrigeration systems than in air-conditioning systems. Thus, safety factors are a practical necessity for refrigeration systems, though the amount of safety factor realized by the installed equipment and systems is rarely quantitatively tested. • Refrigeration systems are custom built from components rather than factory-assembled packages. As such, each system is unique and performance is greatly affected by component interactions and control methods. Compressors and condensers are selected to meet the needs of multiple loads and multiple application conditions, with control valves and electronic control systems often selected and applied by parties different than the provider of the major components.

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1 ~ Introduction

• Retail chain stores and other large users commonly purchase equipment directly from multiple vendors to increase competition and obtain the best-in-class product for each use. Equipment may be specified and purchased under blanket bidding/purchase agreements. • The owner (or engineer) often defines the manufacturer and the type of operating controls energy management system (EMS) that will be included with the equipment from one or more OEMs and installed by one or more contractors and then addressed by another controls contractor to include HVAC and lighting. This increases the integration challenges and can contribute to uncertain responsibilities and a lack of coordination between system design features, control system capability, and programming. As previously stated, this Guide is intended to address the needs of all custom-designed refrigeration systems, including those for industrial applications, retail food stores, and other commercial applications. However, retail food stores provided the largest source of examples concerning design, construction, and facility operations, and the examples vary by business size (including national chains, independent chains, and individually owned stores), responsibility for design and design methods, contracting choices, and type of maintenance operations. Historically a large portion of refrigeration design in this sector has been provided by manufacturers and design-build contractors, along with a smaller portion of owner-designed and consultantdesigned refrigeration and HVAC systems. Plus, supermarkets are remodeled and expanded over the life of the facility, providing multiple opportunities to realize benefits from commissioning. Using examples from this wide range of industry characteristics has resulted in a Guide that is expected to be adaptable to other industrial and commercial refrigeration applications. Because commissioning is undertaken to achieve a project that meets owner expectations, this Guide is designed on the assumption that the owner (or owner’s representative) will provide the assignment, directions, and overall impetus for commissioning. Commissioning will be most successful when all project participants fully understand the commissioning process and take initiative and action in their areas of responsibility and expertise. There are two major aspects of the Guide: the commissioning process and the technical procedures used in commissioning. The process could be considered the “business of commissioning” while the procedures are the “nuts and bolts” (i.e., how to commission). In some cases, these constructs may overlap or not be perfectly separated. Users of the Guide may choose to draw the line between the process and technical procedures in a manner that best suits their businesses and facility designs and construction methods. This Guide provides examples of only the most common technical procedures; individual Commissioning Plans should include the identification and development of project-specific technical procedures to ensure effective component- and system-level commissioning.

HOW TO USE THIS GUIDE

Refrigeration Commissioning Guide for Commercial and Industrial Systems traces the development of refrigeration systems from concept through design, construction, and start-up. Chapters 2, 3, and 4 cover the phases of commissioning: Planning and Design, Construction and Installation, and

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Start-Up and First-Year Operation. Each chapter includes a flowchart with steps outlined that users can follow to ensure that the end result will meet the expectations of the owner as well as a roles and responsibilities table that breaks out the possible interested parties and their involvement in the commissioning process. Sidebars are dispersed throughout the Guide to offer realworld examples to strengthen points and provide additional ideas and insights. The appendices provide resources for viewing the roles and responsibilities of people involved in commissioning for all phases in one table (Appendix A), an example Commissioning Plan (Appendix B), an example acceptance plan (Appendix C), and technical procedures that describe activities that may be conducted when commissioning refrigeration systems (Appendix D). Also included is a glossary of terms commonly used in refrigeration commissioning practice. During the development of this Guide there was much discussion regarding the need for consistent terminology within the refrigeration industry, and the committee spent some time coming to a consensus on the terminology and acronyms used in this Guide. Though there is no separate acronyms section included, the acronyms are indicated throughout the text when the terms are used and they are included in the glossary entries.

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2 Commissioning during Planning and Design

INTRODUCTION Objectives

The core objective of commissioning during planning and design is to ensure that a project is designed to be “commissionable.” Starting the commissioning process in this phase helps to establish a framework by which commissioning is embedded in the project from the beginning. Specifically, it ensures that the Owner’s Project Requirements (OPR) are the foundation of the project and that all subsequent phases of the project are based on this welldefined set of requirements. This chapter describes the key documents developed and activities undertaken in this phase to help ensure the project achieves the goals defined in the OPR and to facilitate commissioning of the project.

Process

The main commissioning activities during the Planning and Design Phase are the development or compilation of several key documents: the OPR, the Basis of Design (BoD), and construction documents (CDs). The Commissioning Plan is developed and refined concurrent with development of these documents. As explained in ASHRAE Guideline 0 (2005), the OPR describes what the owner’s requirements are for the project, the CDs show how the requirements are tangibly met, and the BoD ties the two together. Although these documents are developed during the Planning and Design Phase, they must be revisited and revised as needed throughout the project. For example, if a requirement in the OPR cannot be met, the designer must specify why in the BoD, detail what was done instead, and seek approval from the owner to have the OPR revised. In this regard, the OPR, BoD, and CDs, along with the Commissioning Plan, will be living documents throughout the life of the project. As the project progresses and new team members become involved in the project, these foundational documents must be made available and presented with clear expectations so that everyone involved may be held accountable. As much as possible, the procedures, documents, guidelines, and forms to be used during the construction, start-up, and first-year commissioning activities should be identified during the project design, realizing that some details may change based on final design, equipment, and vendor selections. An

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

important step during planning and design is to define the details and costs associated with making the facility commissionable and to include information to define expectations and form a basis of comparison. Examples of commissionable items include pressure taps, flowmeters, specifications for data logging and history capacity, etc. These are often relatively minor costs when included in the initial design but can be physically impossible or difficult from a budget standpoint to add after a project is designed and under construction. Figure 2-1 details activities related to commissioning during the Planning and Design Phase and the order in which they should ideally occur. Activities may vary depending on the nature of the project.

Defining the Scope of Commissioning for a Specific Project

The scope of commissioning for a specific project must be defined at the outset of the project by the owner, with involvement of the initial design team and other stakeholders. The owner and executives of the key parties set the tone for commissioning: defining expectations, gaining understanding, and providing the support necessary for success. Defining the commissioning scope includes describing the roles, responsibilities, technical considerations, and processes necessary to achieve the functional and performance goals of the project. Design team members, the owner or owner’s representatives, contractors (in the case of a design-build project), and others involved in planning and design are typically all involved in defining the expectations of facility performance and/or how the facility and systems will be commissioned. Expectations and budgets go hand in hand. Particularly when the commissioning process is new, upper-level management support is essential to help define how commissioning fits into the business process, how financial value will be determined, and how sufficient budgets and manpower support will be allocated. The nature and extent of the commissioning to be performed as well as the expectations that define success must be decided and clearly stated. The areas of design, specification, equipment, construction, and performance that affect commissioning or are affected by commissioning should be decided on in order to define responsibility and involvement. Table 2-1 provides an example means of defining scope and involvement.

Roles and Responsibilities

The roles and responsibilities of all entities directly or indirectly involved in the commissioning process should be established as part of the Commissioning Plan. Key roles in the commissioning process include, but are not limited to, the following: • Owner: The entity who owns the building and the project. The owner may assign a representative to perform commissioning tasks and be responsible for core project parameters such as budget, schedule, and other project-specific restrictions and limitations—typically this person is the owner’s project manager (PM). The owner may set very detailed and specific project requirements or, as in the case of a design-build project, leave more of the means and methods up to the manufacturers and contractors. • Commissioning Authority (CxA): The entity managing the commissioning process. The CxA may be a subcontractor to the designer or an independent contractor but should be independent of the design team so as not to pose a conflict of interest.

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2 ~ Commissioning during Planning and Design

Figure 2-1 Planning and Design Commissioning Flowchart

• Refrigeration Designer: The entity designing the refrigeration system. Depending on the applicable state and local codes, the refrigeration designer may be a licensed, professional Engineer of Record. Depending on the owner or specific project, the refrigeration designer could be an employee of the owner, a consultant to the owner, or an employee of the contractor, such as in a design-build project. ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Table 2-1 Example Scope Definition Document Design Topic

Example Details

Standard Documents

List of standard references and materials used for facility design (e.g., equipment lists, details, specifications) that are to be employed as part of the basis for overall project design.

Site-Specific Documents

List of site-specific development documents (e.g., surveys, planning reports) that are to be employed as part of the basis for overall project design.

Design and Contracting Summary

Definition of intended responsibility for design and construction, including as applicable design professionals, project managers (PMs), consultants, contractors, and how these will be selected at each phase of the project.

Design and Selection Criteria

Ambient conditions, codes and standards, criteria for system options (air vs. water, refrigerants, direct vs. indirect, etc.), guidelines for future capacity and functional flexibility, and tenant requirements.

Design Options

Options to be developed for owner consideration and required analysis (e.g., first cost, energy analysis, life-cycle calculations).

Operational Requirements

Temperature requirements in spaces and for equipment, operational hours, traffic peak and hourly assumptions, pull-down loads, and product definitions.

Economic Considerations

Facility life expectancy, incremental payback requirement, and budgets.

Load Calculations

Definition of responsibility for load calculations, tools to be used (e.g., peak design or modeling), and parameters required for subsequent commissioning.

System Design

Standard product specifications, acceptable manufacturers and product configurations.

HVAC/Mechanical Coordination of space conditions, methods of heat recovery, and Integration requirements for performance measurement and commissioning.

Control System Integration

Network design, integration with other systems, standard vendors or functional requirements, and functional definitions—where responsibilities, required level of detail, and sensor and data requirements must be adequately defined to support the commissioning process during system troubleshooting.

• Refrigeration Contractor/Installer: The entity hired to install the refrigeration system or certain aspects thereof. • Refrigeration Original Equipment Manufacturer (OEM): Manufacturer of the refrigeration equipment, e.g., refrigerated cases, compressor racks, condensers, etc. • Other Contractors/Specialists: Other entities hired either directly by the owner or as subcontractors to the designer who are responsible for certain aspects of the refrigeration system or its supporting elements (e.g., a control system contractor). • Building Service, Operations, and Maintenance Staff: People who will occupy, operate, and support the refrigeration system and the building itself throughout the life of the system. Table 2-2 shows an example of commissioning roles and responsibilities during the Planning and Design Phase. This table is an example for a project

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2 ~ Commissioning during Planning and Design

Table 2-2 Example of Roles and Responsibilities Matrix in the Planning and Design Phase for an Owner-Specified Project Role

Responsibilities in the Planning and Design Phase

Owner or Owner’s Representative

• Provide OPR, site information, financial information, and product/equipment specifications. • If desired, undertake cost/benefit analysis of energysaving features. • Provide direction on the extent of required commissioning to be reflected in the OPR and Commissioning Plan. • Review and approve BoD, Commissioning Plan, CDs, and sequence of operations (SoO) and accept deliverables. • Identify which technical procedures must be performed as part of the commissioning process.

Commissioning Authority (CxA)

• Lead development of Commissioning Plan. • Review OPR, BoD, CDs, SoO, and product/equipment specifications. • Work with owner to identify technical procedures that are relevant to the project.

Refrigeration Designer (Engineer of Record)

• Develop the BoD, CDs, and SoO. • Review product/equipment specifications and modify as needed. • Provide input on cost/benefit analysis of energy-saving features, Commissioning Plan, and systems manual.

Refrigeration Original Equipment Manufacturers (OEMs)

• Provide input on cost/benefit analysis of energy-saving features.

Control System Contractor

• Provide input on cost/benefit analysis of energy-saving features.

Facility Operations and Maintenance Staff

• Provide input on site information, OPR, and BoD.

that is largely owner specified, with the owner providing many of the system specifications to the refrigeration designer and contractors (as opposed to a design-build project, where the owner may provide minimal detail in the requirements). An example of a full roles and responsibilities matrix for all phases in one table is provided in Appendix A.

FORMING THE COMMISSIONING TEAM

The formation of the Commissioning Team is the first step in successfully executing the commissioning process in the Planning and Design Phase. It is crucial for the owner to have appointed a CxA prior to the development of any project documents or requirements. The CxA can also help the owner decide what other entities are required to make up a complete Commissioning Team and also solicit the appropriate input from the team and the owner to generate project documents. Since the activities of the CxA ideally extend from initial design through the first year of operation, the owner must contract for these services, whether from one entity or several, separate from the construction contracts. The means of contracting for CxA services will vary based on the practice followed by each owner, but a clear delineation of the CxA’s role, responsibilities, and authority is essential. Moreover, the CxA’s activities must be coordinated with the commissioning-related work to be carried out by vendors

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

ROLE AND RESPONSIBILITY OF THE COMMISSIONING AUTHORITY The text included in this sidebar is an excerpt from Annex L of ASHRAE Guideline 0 (2005). This annex provides an example of how to implement part of Guideline 0; it is not intended to be a comprehensive representation or a best practice example. 2. THE COMMISSIONING AUTHORITY (CxA) 2.1 The primary role of the CxA is to verify achievement of the OPR throughout the project, from Pre-Design Phase through Occupancy and Operations Phase. The Owner should perform this role. 2.2 When the Owner cannot perform the CxA duties with qualified personnel, then the CxA should have a separate professional services agreement with the Owner, as this avoids conflicts of interest and provides independence from the other parties (the Owner’s project manager, designers of record, construction managers, suppliers, and construction contractors). This professional services agreement defines the duties, rights, and responsibilities of the CxA for each phase of the project. This separate relationship allows the CxA to act independently as director of Commissioning Process activities, to focus on achieving the OPR, and to communicate directly with the Owner. 2.3 The CxA is a group of personnel with expertise and experience in the design, construction, and operations of the various systems and assem-

blies included in the project. These personnel are led by an individual who has expertise and experience in successfully implementing the Commissioning Process. 2.4 If the CxA is an employee, associate, or partner of the same organization as the designer of record or construction management firm, there is a conflict of interest. While not a recommended approach, in these instances the CxA must have a separate professional services agreement, be organizationally separate from the design team or construction management team, and define and manage the conflicts of interest to provide the Owner with the independence required for the Commissioning Process to be successful. 2.5 The CxA does not perform testing; it directs the process and directs the recording of the results. The CxA plans, schedules, and supervises Commissioning Process activities to verify achievement of the OPR. The Contractor completes construction checklists, performs tests, and accomplishes other Commissioning Process activities.

and contractors as defined in the CDs. As detailed in Annex L of ASHRAE Guideline 0 (2005), the CxA’s role must be considered and refined for each project to suit the owner’s business practices as well as project-specific necessities and constraints. In this Guide it is not assumed that there will be one CxA throughout the entire project. While a single CxA entity is suggested as the best practice model, the industry requires time and experience for these skills and capabilities to develop and be offered by engineering practitioners and service providers. For some companies (e.g., multifacility operations), other methods may be more consistent with their business practices.

Contracting for CxA Services

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The CxA’s role and responsibilities can be defined in a CxA specification or in a project-specific request for proposal (RFP) describing the tasks the CxA will perform at each phase of the project. Annex E of ASHRAE Guideline 0 (2005) provides an example format that can be used to define responsibilities and request proposals for CxA services. Depending on the content of the project documents, the commissioning services may be engaged using one of the following methods: • Solicit proposals from prospective third-party CxAs.

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2 ~ Commissioning during Planning and Design

BEST PRACTICES FOR A COMMISSIONING AUTHORITY: INDEPENDENCE, PERSPECTIVE, AND UNDERSTANDING Commissioning is best achieved when the commissioning authority (CxA) is an independent and impartial third-party entity with the technical skills and process experience to achieve the commissioning objectives while creating value through coordination with all project participants. The greatest independence is achieved when the CxA is not involved in the project design, construction, or ongoing maintenance and operations. This way, not only is the CxA able to bring a fresh perspective to the project but the responsibility for managing the commissioning scope, content, and deadlines is more clearly defined. Being realistic about the “starting point.” At the present time, given both the very limited use of commissioning for commercial and industrial refrigeration systems and the common practice of design-build construction for many commercial and industrial projects, it remains to be seen if and when qualified service providers (who are independent and unrelated to the project) will be available to provide refrigeration commissioning. Most importantly, and the biggest challenge, is that this is a highly technical undertaking. Although the CxA is not the design engineer, the nature of refrigeration commissioning requires that the CxA be highly skilled and experienced in refrigeration system and control technologies in order to work with designers, contractors, vendors, and the maintenance team. If the work of the CxA is performed by the project engineer, project contractor, or designbuild contractor, the commissioning work should be performed by a separate department and staff within that person’s organization. The CxA should not report to the person responsible for the project design, the construction work, or the start-up team. Achieving the desired independence and impartiality will be largely dependent on how the firm is organized and manages their commissioning business.

• Include commissioning responsibilities in the refrigeration contractor’s scope of work. • Usee the owner’s predetermined internal commissioning resources. • Use a prenegotiated third-party CxA.

Specifying Commissioning Activities

The construction contract documents should include the commissioning process activities the contractors are expected to perform during the construction work and through their warranty period. The contract specifications should describe the CxA’s role in each area of responsibly to avoid duplication of effort and cost and to maintain intended responsibilities. Other sources, such as the Commissioning Plan or the technical procedures, which become part of the CDs (described in more detail later in this chapter), may also be leveraged to help define and delineate the CxA and contractors’ scopes of work. Additional information on project bidding and contract placement is outlined in Chapter 3.

DEVELOPING THE OWNER’S PROJECT REQUIREMENTS (OPR)

The commissioning process for any system must begin by defining the Owner’s Project Requirements (OPR). As per ASHRAE Guideline 0, “the Owner’s Project Requirements form the basis from which all design, construction, acceptance, and operational decisions are made. An effective Commissioning Process depends upon a clear, concise, and comprehensive

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Owner’s Project Requirements document. It includes information to help the project team to properly plan, design, construct, operate, and maintain systems and assemblies” (ASHRAE 2005, p. 6). The CxA facilitates the development of the OPR, and in order to successfully develop an effective OPR, the Commissioning Team must be engaged in the process—including the owner or owner’s representative, who is responsible for core project parameters (budget, schedule, etc.). It is also recommended that the building operators, facility managers, store directors, and maintenance personnel be involved in the OPR development. Many times these individuals have valuable insight into the actual operation of the system and facility and can help point out issues that can be addressed during design by influencing the OPR. For example, a supermarket store manager may know from experience that the capacity of the typical ice flaker used may not produce enough ice for the type of service fish cases that are planned to be installed in the store. The OPR could then require the designer to address this particular capacity issue. Depending on the owner, a technical representative (often a mechanical engineer or other technical individual employed by the owner) may be available to represent the owner’s internal goals and directives. For example, the owner’s project manager (PM) may know that certain refrigerants exhibit a global warming potential (GWP) and that it is the goal of their company to reduce their environmental impact by reducing the GWP of their refrigeration systems; however, this person may not personally know what strategies to employ to best deal with the issue. The owner’s technical representative, therefore, would set requirements in the OPR such as what refrigerant should be used, what type of system it should be used in, what charge minimization strategies should be used, what leak prevention efforts should be made, and how the commissioning process will validate the company’s overall environmental strategy. If an internal technical representative does not exist, the owner may rely on the CxA to help effectively communicate the requirements in the OPR. (Refer to the “Roles and Responsibilities” section of this chapter for more detailed information on how the various team members can contribute to the development of the OPR.) Other examples of key items that should be contained in the OPR are discussed in the following sections. Many of the requirements can be considered project specific; however, many of them reflect owner-specific requirements that may not change from project to project, such as the additional requirement of quality for materials and construction. It is important to leverage preestablished owner requirements that may already exist in the form of equipment and installation specifications, owner-developed design and installation guides, or even CD criteria sets. Many owners use these types of documents as a platform to administer their internal goals and directives in a consistent manner, so simply referencing these documents in the OPR can be an effective way of including the requirements they contain.

Key Items to Include in the OPR Project Budget and Schedule 16

Sufficient detail should be included to document the project budget and schedule so that the entire project team knows the limitations. Depending on

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2 ~ Commissioning during Planning and Design

CONDENSER STACK ATTACK—A CASE STUDY Background: Many grocery stores are built fairly close to residential areas and have to address noise issues in order to be good neighbors. Some cities have noise ordinances with specific requirements to keep equipment noise below the established threshold during evening/nighttime hours. Various design solutions may be employed to accommodate these noise abatement requirements. Problem: One design resolution to accommodate noise issues is the “stack attack” option shown in the figure. In this design, condenser fan stacks are installed on top of the condensing equipment. Unfortunately, this particular design solution creates service issues and increases costs associated with changing out the condenser fan motors. It is unlikely that these issues will be realized until problems arise associated with condenser fan motor failures (e.g., high head pressures). When that occurs, it is likely that a crane will be required to safely lift the stacks so the condenser fan motors can be replaced and to reset the stacks onto the condenser when the work is completed. The need for a crane greatly increases the both the costs and time required for what should be routine maintenance. In this particular case study, the cost was increased by $5000 for local crane fees and the replacement took all day. Lessons Learned: Reviewing the OPR and BoD early in this project should have enabled the identification of alternate design options to meet site noise abatement requirements that do not create costly service situations. This design solution created a very expensive service challenge and an unsafe maintenance process. In addition, once installation is complete, retrofitting this type of situation can be expensive, and the process of reviewing information and evaluating supporting systems may impact the operation of the store.

Photograph courtesy of NREL; credit John de la Rosa

Why are Those Stacks on the Condenser Fans?

the type of system to be installed, sufficient budget and time must be allocated to allow for proper design, installation, start-up, and commissioning. Since many refrigeration systems are custom built for the application, input from the designer and/or manufacturer may be necessary to accurately adjust the budget and schedule on a project-by-project basis. ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Commissioning Process Scope and Budget

Identifying the equipment, components, and systems to be commissioned and assigning a budget to carry out the commissioning tasks is essential. Depending on the size of the scope and budget, commissioning could be focused on just the control and operation of the equipment in the compressor room, or it could also include condensers, evaporators, piping systems, pumps, peripheral controls, etc.

Technical Procedures

All technical procedures that will be conducted for commissioning, as specified in the Commissioning Plan (see the section “Developing the Commissioning Plan” in this chapter), must be reviewed, and the CxA must ensure that any information or data necessary for fulfilling a given technical procedure is included in the OPR.

Submittal Requirements

Specify how the submittals will be coordinated, reviewed, and approved and who will be responsible for these functions.

Project Documentation Requirements

With input from the owner’s technical representative and the CxA, specify what documentation will be required for effective commissioning, who will be responsible for providing it, and in what format it should be provided. Depending on the nature of the facility and the owner’s preference, the documentation may include only refrigeration-related content or may address all aspects of the facility. Additionally, the owner should specify a method for retaining, storing, and/or displaying these documents in order to preserve them for the life of the system and to allow for updating as changes, additions, and improvements are made to the documents or the facility itself (see Figure 2-2). As a best practice, documentation retention should include, at a minimum, the following: • Owner’s Project Requirements • Basis of Design documents • Issues log • Construction record documents, specifications, approved submittals, and the construction checklist • Control requirements

Photographs courtesy of NREL; credit John de la Rosa

Figure 2-2 Examples of Displayed Project Documentation

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2 ~ Commissioning during Planning and Design

• • • • •

Start-up records Commissioning report Systems manual (including operations and maintenance manuals) Training materials and optimization guidance Ongoing operating data

Ongoing operating data may include the following: • Refrigerant leak and recharge records • Oil usage log (additions and removal history) • Maintenance and emergency repair records • Equipment logs (periodic manually prepared forms and/or computer printouts)

Training Requirements for Owner’s Personnel

The CxA and all parties who will provide training information should be involved in the development of training requirements and expectations. Input from those who will be responsible for using the training materials is also important. The expectation for sufficient training should be documented and communicated directly with the expected trainer or included within any applicable RFP. Typically, system manufacturers will offer some sort of training for equipment that is considered unique or a new technology. For example, refrigerated display cases may require training on how to properly load the cases or operate various features of the cases. In addition, the training process and timing must be defined. While multiple entities may be involved with aspects of training, particularly on a large project or with new technologies, training coordination is necessary to ensure information is fully and effectively made available on a timely basis to the individuals who need it. Chapter 4 discusses how to review the training activity during the Start-Up and First-Year Operation Phase. Developing training requirements and implementing training for a project involves the following actions: • Identifying who requires training, when, and how frequently • Defining who will provide training (e.g., vendors, engineers, training or subject specialists, etc.) • Establishing a training calendar for the project • Identifying additional requirements for new technologies or special installation conditions • Identifying certifications required of operating staff or contractors • Specifying safety-related requirements per company policy and governmental agencies (e.g., local codes, Occupational Safety and Health Administration, Environmental Protection Agency, etc.) • Providing safety training before start-up or change activities • Providing safety training after completion, with hands-on interaction • Providing individual safety qualification on standard operating procedure (SOP), when applicable • Providing training on remote access, control interface, and other data systems • Defining the responsibility for maintaining and administering ongoing references and training support

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Warranty Requirements

The terms of warranty for all systems and components to be commissioned should be collected and included in the OPR for reference so that all warranties may be preserved throughout the project. Chapter 4 discusses how to review warranty requirements during start-up and through the first year of operation.

Benchmarking Requirements

Beyond requiring that benchmarking must be part of the Commissioning Plan, the owner must specify what the benchmark targets will be, when the benchmarking should happen, what the means of measurement are, and what the benchmark deliverable needs to look like. The CxA should help develop these requirements to ensure that the commissioning work performed and the generated deliverable is as meaningful as possible. For example, if weather data and facility conditions are not recorded when the system benchmark is recorded, then the information cannot be used to its full potential. Chapter 4 discusses the documentation of performance benchmarks during first-year operation.

Operation and Maintenance Requirements

Include expectations regarding the yearly maintenance budget and the expected capability of the service contractor. To realistically set these requirements, collaboration with the service technician may be required.

Load and Sizing Calculations

Designate the responsibility for performing load calculations and define the operational parameters, derating or safety factors, and related system-sizing criteria. Adherence to these design parameters and responsibilities should be maintained during the development of the design. Once the system becomes operational, commissioning feedback should be provided regarding the efficacy of the load and sizing calculations and methods.

Environmental Sustainability and Energy-Efficiency Goals

Environmental goals can be expressed in the OPR in many ways, such as dictating what type of refrigerant to use, what the total refrigerant charge should be, how much energy the refrigeration system should use, or even what the system’s total equivalent warming impact (TEWI) or life-cycle climate performance (LCCP) number should be. As previously discussed, depending on the level of internal technical representation available to the owner, the specifics of how to achieve these environmental goals may or may not be included in the OPR. The requirement should still be firm, but it may leave more of the means and methods up to the designer to achieve the end goal. Any requirements for obtaining building ratings or certifications (e.g, bEQ, LEED®, Green Globes, GreenChill, or ENERGY STAR®) should be specified. The targeted level of awarded certification should also be expressed. The energy goals of a project are directly related to the environmental goals and, similarly, there are many different ways to address the requirements. Some of the ways to set the energy requirements are • requiring equipment to meet a specified payback period, • referencing an industry energy baseline and requiring that the system either meet this baseline or achieve a certain percentage deviation from it, or • requiring that the equipment meet a certain preset performance specification that can be verified through kilowatt-hour monitoring.

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2 ~ Commissioning during Planning and Design

System Type

The system type is requirement that cannot necessarily be set until after the environmental and energy goals have been identified. Sometimes, the environmental and energy goals will require the use of a type of system that the owner has no experience with. While some owners may give the designer the authority to simply pick a system type and manufacturer that fits their design, many owners have a selection of approved manufacturers and system types that they will require to be used.

Community Requirements

The owner should understand the surrounding community and set requirements to make sure that the team and the installed systems do not negatively impact that community. Sometimes community engagement will be necessary to successfully complete a project. For example, projects where visible and/or audible rooftop equipment will be installed may require approval from surrounding neighbors. With the use of some “natural” refrigerants, the Emergency Planning and Community Right-to-Know Act of 1986 (EPCRA) may come into play and require that certain steps are taken to properly engage the community.

Refrigerant Charge Calculations and Refrigerant Management

The OPR should clearly define the responsibility for calculation of refrigerant charge(s), confirmation of actual system charge, and identification of any leaks or adjustments needed to accurately define the proper operating system charge. In order to improve future designs, also define the responsibility for investigating variances from the expected charge and report reasons. Define the management systems for tracking refrigerant use from start-up through the first year of operation, including continuity between construction and maintenance record keeping.

Adaptability

The OPR should specify whether the installed system should be able to adapt and expand to meet the predicted future needs of the facility and, if it should, to what degree it should be able to do so.

Systems Integration Requirements

Include any requirements to integrate the refrigeration system with other systems such as space heating, water heating, lighting, facility control, etc.

Acoustical Requirements

List baseline acoustical requirements and express additional requirements for special situations. Examples of special situations include mechanical room walls that are shared with other tenants or neighbors that are in close proximity to rooftop condensers.

Vibration Requirements

List vibrational requirements, especially when nontypical roof systems or mezzanines are used to support condensers and compressors. Also include seismic requirements for projects that are located in special seismic zones.

Constructability Requirements

In addition to recording any known constructability restrictions specific to the project site, the owner may choose to require that a constructability review be performed by the installing contractor once the CD permit set is issued. The project schedule and construction schedule should be reviewed to make sure that the pieces can come together in the right order. One example of this is ensuring that roof curbing is set before condensers are craned to the roof so that the racks can be ready to run when the evaporators are needed to refrigerate.

Maintainability and Accessibility Requirements

Set requirements for equipment accessibility to allow for proper and efficient maintenance. This is a requirement that will demand some architectural coordination to ensure that spaces adequately allow for proper clearances and

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

pathways. Proper storage and trash handling should be addressed to reduce garbage and clutter around equipment.

Communication Requirements

Include any remote monitoring requirements for the purposes of maintenance, trend logging, or performance comparisons.

Systems Communication and Controller Requirements

Aside from specifying which controls manufacturer should be used, specify what communications should take place between integrated systems. Beyond this, the expectation should be set for the designer and the controller programmer to closely coordinate throughout the project to ensure that the design intent is executed in the final control of the system (refer to the sidebar “Sensors for Condenser Control—A Case Study” for more information). To accomplish this coordination, the owner may require that the designer develop a sequence of operations (SoO) for the system and include it in the BoD and CDs.

New Technology Requirements

Include any requirements to use the latest advancements in technologies. Current examples of the latest advancements include electronic expansion valves (EEVs), electronic evaporator pressure regulators (EEPRs), digital compressor unloading, variable-speed electrically commutated (EC) motors, etc.

SENSORS FOR CONDENSER CONTROL—A CASE STUDY Background: A supermarket remodel and expansion was designed to use closed-loop evaporative fluid coolers for heat rejection connected to water-cooled condensers at the refrigeration racks (see the figure). The two fluid coolers used 30 hp (22.5 kW) motors equipped with variablespeed motors and were to provide floating head pressure using a variable setpoint (i.e., wet-bulbfollowing) control strategy. The chain, which more commonly used air-cooled condensers, had developed this system design to save energy in hot, dry climates as well as to reduce refrigerant charge. Problem: During a store visit on a cool, dry day, well after the store opened, the fluid cooler fans were observed at minimum speed, concurrent with near design condensing temperatures. Investigation determined that the sensors for the wet-bulb-following strategy were missing and were not shown on the drawings. In addition, the controller was set for a high, fixed head pressure. The design concept (and significant capital investment) was undone by this control deficiency. By simple rule of thumb (1.5% to 2% energy per degree Fahrenheit of condensing temperature), the loss in efficiency during average weather conditions would exceed 20%. The importance and lost savings are as follows: Annual refrigeration, kWh Annual refrigeration operating cost Cost to correct controls Payback

Before 900,000 $120,000

After 700,000 $100,000

Savings 200,000 $20,000 $2500 2 months

The necessary control changes were made at low cost, although with some effort, since it was found that the controller model had certain logic limitations, which may explain why the needed sensor had been deleted in the first place.

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2 ~ Commissioning during Planning and Design

Schematic of Fluid Cooler/Condenser Loop

Lesson Learned: The sequence of operations (SoO) typically employed by this chain to define control operation either was not completed or was not coordinated with the mechanical design incorporating a fluid cooler system. From an economic standpoint, the extra capital invested in the fluid cooler system was wasted without the appropriate sensor and control logic. The missing sensors and/or control system limitations would have been more evident, taken on higher importance, and likely been addressed if a CxA had been • involved in the Planning and Design Phase, • looking forward to the expected goals at project start-up, • armed with the design intent as defined in the BoD, and • aware of the financial implications. The lack of a key sensor or fundamental control strategy from the drawings would be apparent to the CxA during construction and start-up only if the overarching objectives were understood—in this case that would include floating head pressure, which was standard practice for this owner. Had this project included commissioning, the desired action by the CxA would have been to identify the technical solution, budget, and responsibility for changes to achieve the design intent; to ensure that the changes were completed and verified; and to provide feedback to address the same deficiency in other stores of the same vintage. This example shows the type of responsibility and authority required to deal with one particular issue. While the economics shown are striking, often the impacts are not at all as obvious during construction. The CxA frequently needs to understand the economic ramifications in order to justify the effort required to identify and enact changes that require research, design, and work by multiple trades.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

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Applicable Code, Standard, and Guideline Requirements

In addition to the state and federal codes that must be followed, the OPR should make it clear whether there are any additional applicable standards or guidelines that should be followed for the project.

System Redundancy Requirements

Specify the level of redundancy that should be accounted for in the design. Redundancy requirements could be applied to many different aspects of design, such as compressor or pump redundancy—or even to the load. For example, the owner could require that the frozen temperature evaporators be split across multiple different compressors (or compressor racks) so that if one is lost the frozen product may be restocked to other frozen cases or freezer boxes.

Compressor Staging Requirements

Along with the redundancy and safety factor requirements, the OPR should express the requirements for proper equipment staging to react to reduced loads and increased system capacities due to low-ambient conditions. This requirement can be set in various degrees of detail, leaving more or less of the means and methods for achieving proper staging to the designer.

Power Failure Requirements

Since refrigeration systems often protect thousands of dollars of product that will be lost if the refrigeration system loses power, the OPR should include any requirements for how the system should react to power failure.

MANAGING THE ISSUES LOG

The issues log contains detailed descriptions of any design, installation, and performance issues that are at variance with the OPR. Issues are identified and tracked as they are encountered and resolved through all phases of commissioning. It is particularly important to establish responsibility for maintaining the log at the beginning of the project and, if the entity responsible changes over the course of the project, have an effective means for transferring responsibility to maintain continuity. The issues log is a living document that tracks issues from their initial identification to their closure. Once an issue is identified, it should be recorded in the issues log along with an initial plan for resolving it. As steps are taken toward resolution, each step should be documented. Finally, once an issue is closed (whether or not it is resolved as planned) the outcome should be noted and preserved in the issues log for future reference. For each item in the issues log, information to be documented may include the following: • Issue number: a unique issue identifier for location in a database • Date the issue was identified • Who identified the issue • Description of the issue • Initial recommendations for issue resolution • Who is responsible for resolving the issue (may be more than one entity) • Date entity responsible for resolution was notified of the issue • Steps taken toward resolution and dates these steps occurred • Status of issue (open or closed) • Date of resolution • Probable benefits to the owner (economic or otherwise) of resolving the issue

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2 ~ Commissioning during Planning and Design

The format for the log (e.g., electronic or paper, list or table) should also be established at the outset of the project. Examples of two different templates for formatting an issues log are shown in Table 2-3 and Figure 2-3. Table 2-3 is a spreadsheet where each issue corresponds to a line on the sheet. This example may be best suited for an online database or computer file. Advantages of this format are that multiple issues can be viewed side by side and the issues can easily be sorted based on various characteristics. In Figure 2-3, each issue is described on a one-page worksheet. This example may be best suited for a binder on site, with several blank sheets for issues that come up during the course of the project. Advantages of this format are that all details on a particular issue are in one place and easy to track and the sheets can easily be annotated in the field as steps are taken to resolve the issues.

DEVELOPING THE COMMISSIONING PLAN

A well-developed Commissioning Plan is vital to the overall commissioning process and should define the processes and activities necessary to achieve the intended facility performance. Once the OPR has been defined, an initial Commissioning Plan may be developed to guide the commissioning efforts through the Planning and Design Phase of the project and give a basic structure to the commissioning efforts through the life of the project. The Commissioning Plan will require revisions and additions throughout the Planning and Design Phase to ensure that it captures all supporting processes and activities for the final system design and for the subsequent phases of the project. Even if a formal OPR is not developed, or is not defined as such, the Commissioning Plan has the purpose of ensuring that the intended operational performance of the system over the life of the facility is realized. Because of the variance in design and configuration from one project to another, the Commissioning Plan for the refrigeration system will most likely be unique for each project, even for repetitive chain store projects. Nonetheless, the Commissioning Plan should be developed in the Planning and Design Phase of the project to help ensure that the system is commissionable as it is designed and built. As described in the Introduction, commissioning is a process involving multiple parties beginning with the initial project design and extending past

Table 2-3 Example Issues Log—Electronic Version

#

Issue

Issue Description

Date Date Contractor Contractor Identified Responsible Notified

Action Taken

Issue Resolution (Open / Date Closed) Resolved

1

2

Etc.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Issue #: Project Name: Project ID: Prepared by:

Date:

Submitter of Issue:

Date found:

Name of Issue: Description of Issue:

Possible Cause:

Recommendations:

Contractor Responsible:

Date notified:

Actions taken:

Date issue resolved: Benefits Economical range:

$

to $

Most probable certain benefit to owner: Most probable benefit to design team: Most probable benefit to construction team: Noneconomic benefits to the building:

Figure 2-3 Example Issues Log—Paper Version

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2 ~ Commissioning during Planning and Design

start-up. In addition to the primary design team, there are many others to consider in developing the Commissioning Plan. Selected contractors, vendors, manufacturers, and service providers need to understand what commissioning is and what it means to the project. Their roles and expected involvement must be clearly defined. The Commissioning Plan spans a time period including • design, • construction and installation, • start-up and opening, and • the first year of operation. The Commissioning Plan includes • management responsibility; • activities, including technical procedures, to be performed; • individual responsibilities; • documentation requirements; • evaluation methods; and • reporting requirements. The Commissioning Plan must be reviewed and updated periodically during the project (at least once during each project phase) as additional information is obtained. Situations that could impact the Commissioning Plan include the following: • Procedures for timing of equipment selection, which vary from company to company. • The choice of design-bid vs. design-build contracting, which affects responsibilities, budgets, and timing. • The addition of team members during the project process. • Design changes and option selections that occur over the course of the project, which often impact facility performance. The following sections should be considered in developing the Commissioning Plan. Appendix B of this Guide includes an example Commissioning Plan and illustrates additional details for these sections. 1. Overview—Summarize the purpose and use of the Commissioning Plan. 2. Roles and Responsibilities—Define responsibilities for management and implementation of commissioning at each step of the process. The Commissioning Plan should include a list of team members involved in the project and their contact information. Examples include consultants, contractors, and staff. Commissioning is not a replacement for system start-up responsibilities or installation quality assurance, which should be defined in construction contracts and vendor agreements. The roles and responsibilities for commissioning work should be clearly distinguished from the construction activities. 3. Communications—Define the frequency and timing of communication as well as who has responsibility for disseminating information and reports throughout the commissioning process. ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

DOE REFRIGERATED CASE STANDARDS The recent work of the U.S. Department of Energy (DOE) on 10 CFR 431, Part III, assigned classification to commercial refrigeration display cases. This work established standardization for the calculation of case energy by class of case, which supports the designer with a higher definition of system load/balance. Tables summarizing these standards are available on the DOE Energy Efficiency & Renewable Energy (EERE) Building Technologies Office website under Appliance & Equipment Standards for Commercial Refrigeration Equipment: www1.eere.energy.gov/buildings/appliance _standards/product.aspx/productid/52.

4. Schedule—Develop a schedule of key milestones and activities. As the project progresses, the schedule should be updated with actual dates, events, and resolutions. 5. Commissioning Processes—Detail the site-specific activities developed to achieve commissioning goals and define the following for each phase of the project: • Planning and Design • Construction and Installation • Start-Up and First-Year Operation An important aspect of the Commissioning Plan is defining the design and decision-making responsibilities, information needs, and sequence of events necessary to accomplish the technical aspects of commissioning. Specifically, the Commissioning Plan should detail how performance expectations are to be defined and measured and should outline key equipment specifications that are easily addressed at the right time but can be physically impossible or too expensive to address once equipment is ordered or construction is complete. Examples of key equipment specifications include pressure taps, flowmeters, specifications for data logging and history capacity, etc.

DEVELOPING THE BASIS OF DESIGN (BoD)

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According to ASHRAE Guideline 0, the BoD is “a document that records the concepts, calculations, decisions, and product selections used to meet the Owner’s Project Requirements and to satisfy applicable regulatory requirements, standards, and guidelines. The document includes both narrative descriptions and lists of individual items that support the design process” (ASHRAE 2005, p. 4). Since the design process is a somewhat linear process, the BoD will be incrementally developed as the design is developed. Once the design is complete, the BoD will need updating only when design changes are a result of the OPR being revised. The expectation then is for the CxA to use the most up-to-date BoD to effectively commission the CDs and ensure that the OPR is being satisfied by the design. This is one of the most important tasks for the CxA during the Planning and Design Phase since it allows issues and concerns to surface as the design is being developed. The technical procedures being performed as part of commissioning should also be reviewed, and

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2 ~ Commissioning during Planning and Design

any information that must be included in the BoD to successfully perform each procedure should be added to the BoD. In summary, the BoD should address all of the major requirements included in the OPR. To best illustrate how the BoD accomplishes this task, some basic examples are given in Table 2-4, in the order that they would likely

COMPRESSOR PERFORMANCE: RATED VS. APPLIED CONDITIONS AND IMPLICATIONS FOR DESIGN AND COMMISSIONING The current design practice and difference between nominal rated compressor capacity (CC) and applied conditions results in a large difference between apparent and actual capacity, particularly for commercial refrigeration applications. The capacity on paper is not the real capacity, which has implications for the commissioning process and procedures, since commissioning fundamentally is addressing expected vs. actual performance. This situation provides an example of the necessary interaction and relationship between design practice and commissioning. In terms of achieving the desired cooling capacity and temperatures, compressors are the most important component in a refrigeration system. Since temperatures in most applications must be met 100% of the time, systems are naturally designed from a conservative point of view—the consequences of not meeting temperatures are expensive to resolve and very unattractive for all involved. This is in contrast to commercial HVAC systems wherein, for cost-effectiveness, good design practice expects temperatures will exceed design conditions for a few hours out of the year. A consequence of this difference is that HVAC load calculations and system capacity are honed by “being on the edge,” in contrast to refrigeration applications where a system with “unmet cooling hours” is completely unacceptable. Low-temperature compressors will most often be much more heavily loaded than mediumtemperature compressors. In fact, it isn’t unusual for all low-temperature compressors to be running when only half of the medium-temperature compressors are on. And, on paper, medium-temperature systems often have less safety factor. While this may be due to greater load diversity on medium-temperature systems or differences in how walk-in loads are calculated, the main issue is usually a striking difference in how the compressors are rated and applied. Commercial refrigeration compressors are rated based on ANSI/AHRI Standard 540 (2004), which include a fixed 65°F (18°C) return gas temperature (RGT) entering the compressor, regardless of the saturated suction temperature (SST). This means that the rated capacity for a compressor operating at –20°F (–29°C) assumes all heat required to superheat the suction gas to 65°F (18°C) is productive refrigeration, whereas the actual productive suction gas temperature is likely no greater than 0°F (–18°C), the temperature leaving the display case or freezer box. The discrepancy between rated capacity and the actual cooling capacity is often 20% or more. This appears to be addressed by compressor manufacturers’ software, which provides for variable suction gas temperature. However, the software adjustments are approximations (generally a simple ratio of suction gas density), not based on additional compressor testing at more common conditions. This historical discrepancy in compressor ratings is inherent to the process of design practice, load calculations, and general experience and expertise in the industry. Safety factors and capacity adjustments have evolved from experience and will continue to improve. In this example, the need is for improved compressor rating conditions and testing along with a better understanding of actual loads. The figures help illustrate these concepts by describing productive and nonproductive superheat by defining points on a pressure-enthalpy diagram and a physical refrigeration system schematic.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Graphics courtesy of VaCom Technologies

Refrigeration Cycle with Productive and Nonproductive Superheat (SH): Schematic (top left), Graph (top right), and Pressure-Enthalpy Diagram (bottom)

How does this relate to commissioning? One point is that commissioning efforts will be successful only to the extent the current state of the art and design practice are understood and taken into account by all of the right parties. If a CxA sets about to compare expected vs. actual capacity without a sufficient understanding of the technical issues, the results may be disappointing. On the other hand, the commissioning effort helps identify and emphasize discrepancies and contradictions, which can accelerate better design. Summary: Moving beyond the “this is how we’ve always done it” mentality is inherent in the overall commissioning process and will drive more sustainable design and operations. This requires close cooperation and knowledge sharing between the CxA and design experts. Some improvements will take time and multiple project cycles but will be very valuable.

be developed. Please note that these examples illustrate how the BoD should respond and react to some specific requirements that might be found in an OPR. The requirements listed may or may not represent best practices or recommended specifications that owners should adopt. For example, the first requirement in Table 2-4 is to use the 0.4% ASHRAE weather data (2013a) to determine the design-day ambient temperature. It is not the intent to imply

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2 ~ Commissioning during Planning and Design

Table 2-4 Example OPR and BoD Language Example Requirements in the OPR Ambient temperatures used for design-day calculations are to be the “0.4% dry-bulb” temperatures as published by ASHRAE (ASHRAE Handbook—Fundamentals, 2013). Round 0.4% dry-bulb (db) temperature up to nearest 5 degree increment. Use evaporativecooled technology when ambient temperature exceeds 105°F.

Corresponding Example Information in the BoD



The 0.4% db temperature for Anywhere, USA = 92°F. The design-day ambient temperature used in design is therefore 95°F. Air-cooled condensers were selected because the calculated design ambient temperature does not exceed 105°F.

Given the ambient design temperature on the design day of 95°F, the condensing temperature has been selected at 105°F. The condensers have been selected to meet a minimum of 10°F of temperature difference (TD) without safety factor per the calculation below: Air-cooled condensers shall be sized to meet, on the design day, an actual operating temperature difference (TD) between 8 and 10 degrees Fahrenheit to help meet the energyefficiency goal for the system.



THR------------=  THR  1TD  Condenser 10TD Since the actual condensers have been selected with safety factor, the actual TDs have been calculated per the equation below and fall between 8 and 10 degrees Fahrenheit.

THR T D Actual = ------------------------------ THR  1TD 

Condensers are to be protected from the outdoor elements when threatened. Condensers are also to be visually screened when required. If screening is required, condenser operation shall not be hindered.



Due to the site location, there is no threat of hail requiring hail guards for condensing units; however, since the project is five miles from the coast, condenser fins will be specified with corrosion protection from the saltwater breeze. Furthermore, since there is a residential neighborhood on the hillside behind the premises, condenser screening will be required. Screening will be offset from the condensers a distance of 8 ft minimum on all sides to allow for proper airflow.

This project is to achieve Gold GreenChill certification. Only owner-approved, applicable methods for achieving a reduced refrigerant charge are to be employed.



Design decisions made that will help the owner reduce refrigerant charge as much as possible are as follows: • Use microchannel condensers • Use “loop piping” • Use subcooling on low and medium temp racks.*

Compressor selections per suction group are to be made to meet the number of stages as outlined in the compressor rack specification section based on the number of compressors per suction group. If the number of stages cannot be met, use variable-frequency technology.



The number of Rack ‘A’ capacity steps in the design is 18, which meets the minimum of 14 for a 4-compressor rack as outlined in the compressor rack specification.

* Note: In the commissioning process, the CxA may review this portion of the BoD and realize that the designer missed an important opportunity to further reduce the refrigerant charge by not using a more effective solution that had been approved by the owner on a previous project, such as using distributed rack systems with water-cooled condensers, for example. The goal would be for the CxA to continually commission the BoD as it is developed to catch opportunities for change early in the design development so that the design can be adjusted while that can be done with little or no cost impact.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

that there are days when refrigeration systems are not required to adequately refrigerate. In this specific example, there would be other safety factors built into the design elsewhere per the OPR. Being mindful of the fact that temperatures may rise higher than the design temperature requires a careful balance of safety factor without grossly oversizing the system—which may create other system issues.

REQUIREMENTS FOR CONSTRUCTION DOCUMENTS (CDs)

In the commissioning process, the development of the construction documents (CDs) coincides with the development of the BoD but provides the finer details for the design that is discussed in the BoD. Ultimately, the CDs must contain enough information so that the requirements in the OPR can be met. One reason to develop a set of CDs is to provide a clear scope of work for contractors so that they can provide accurate and competitive bids. Not only is the contractor bound to perform the scope of work defined in the CDs for the price quoted, but the contractor must also deliver an end product that meets

COMPRESSOR SPECIFICATIONS TO MEET SYSTEM PERFORMANCE EXPECTATIONS—A CASE STUDY Background: A large refrigerated distribution center constructed an expansion with a new freezer and new cooler and dock spaces as well as new compressors, vessels, and condensers. The project was fast-tracked and designed to be energy efficient, with well-insulated walls, large condensers, and careful matching of various loads to system suction levels. The control system included variable-speed drives (VSDs) on condenser fans and specified floating head pressure to save energy, with the expectation that condensing temperature could reduce to 70°F (21°C) when ambient conditions allowed. Problem: After start-up the control system was set to floating head pressure but the new highstage compressors experienced excessive oil usage. The problem was easily determined—the screw compressor oil separators had been sized to operate at 95°F (35°C) condensing temperature (196 psig [1351 kPa gauge] for ammonia); at lower pressures (and thus higher velocities for the same mass flow) the compressors experienced oil carryover. The compressors, purchased with competitive bidding after the consulting engineer finished the project design, used the smallest feasible oil separator. Since this limitation affected the entire refrigeration plant, the annual operating cost impact exceeded $75,000. More than two years later, the oil separators were upgraded to allow floating head pressure as originally intended. Lesson Learned: This example points to the need for interaction and understanding along with better communication on the project expectations and the needs to meet those expectations. This problem would not have occurred if the design engineer had a full understanding of the overall energy-efficiency goals (e.g., floating head pressure) and the technical implications concerning compressors (oil separator design) and had also been involved in compressor bidding and review of submittals. Bringing in the CxA during the construction and start-up process would have been too late to resolve this problem. Since the oil separator is the primary vessel and mounting base for a screw compressor package, once the package is built the oil separator design cannot be changed (see figure).

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2 ~ Commissioning during Planning and Design

Photograph courtesy of Johnson Controls

Typical Screw Compressor Package with Oil Separator Highlighted

However, this error could have been avoided in the Planning and Design Phase. To the extent that the commissioning process improves understanding and coordination of overall goals, incorporating commissioning from the beginning may have been beneficial. This example also points out the essential need for thorough expertise in the subject matter in addition to the process of commissioning. Specifically relating this to the commissioning process steps, • the OPR should state the requirement for floating head pressure, • the designer should explain in the BoD how the design meets this requirement, and • the CxA involved in the Planning and Design Phase should review the BoD to ensure that the CDs properly address the specific equipment features.

the design intent that is spelled out in the CDs. Since the CDs contain enough information to allow a contractor to place a bid and install the system, they must be relatively complete documents even in the absence of a commissioning process. However, there are additional requirements for the CDs if the system is to be adequately commissioned. The designer responsible for producing the CDs must become familiar with the commissioning plan so that the design can adequately support the commissioning activities and technical procedures that will occur during construction and start-up. For example, adequate pressure and temperature sensors should be specified for installation in the CDs if they will be a prerequisite to perform some commissioning task later in the project. Similarly, the theory or sequence of operations (SoO) should be included with the CDs so that it is clear to the entire commissioning team how the system is intended to operate. For example, the refrigeration ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

contractor may be required to perform prefunctional testing or help the CxA perform this testing; therefore, it needs to be made clear to the bidding contractors where to find all of their expected scope of work if it is not included in the specifications and CDs. Annex L of ASHRAE Guideline 0 (2005) provides an example strategy for including commissioning activities in CD specifications based on standard MASTERSPEC® section numbers. While refrigeration commissioning is generally focused on the refrigeration system itself, in many instances other trades require definition of commissioning responsibilities and coordination related to refrigeration. This is particularly true as control energy management system (EMS) and safety/alarm systems become more integrated. Some of the commissioning activities to be included in CD specifications include the following: 1. An overall explanation of commissioning and the CxA activities the owner has contracted for. 2. Requirements to participate in meetings and other communications requirements. 3. Submittal requirements related to accommodating commissioning in equipment and system design. 4. Definition of tests that require CxA notice, attendance, and/or approval. 5. Time requirements for commissioning activities. 6. Milestones, notice requirements, testing, and approval process related to CxA for project close-out. 7. Required checklists associated with commissioning. 8. Testing prerequisites to include commissioning technical procedures and CxA involvement. 9. Personnel qualifications, manufacturer representation, and other resource requirements during testing. 10. System and assembly test requirements related to commissioning and CxA involvement.

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DELIVERABLES AND ACCEPTANCE

Commissioning activities undertaken during the Planning and Design Phase are meant to prepare for commissioning the project at future phases. As such, it is essential that documents produced, knowledge gained, and unresolved problems identified must be passed on to those responsible for implementing future phases of the project. Having a defined set of deliverables and a formal acceptance process helps ensure this continuity throughout phases.

Deliverables

All deliverables for this phase must be submitted both to the owner and to those responsible for construction and installation, and copies should be maintained in an easily accessible location. Additionally, if there is a change in the person or people responsible for commissioning from one phase to another, deliverables must be transferred to them as well. The key deliverables for this phase are the following: • Commissioning Plan • Issues log • OPR • BoD

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2 ~ Commissioning during Planning and Design

• CDs • Specifications Other deliverables, if generated during this phase, may include the following: • Building simulation • Cost/benefit analysis of energy-saving features • Sequence of operations (SoO) • Major equipment specifications

Acceptance

Acceptance is a critical process by which the owner or owner’s representative and those involved in the next phase of the project “accept” the deliverables and commissioning activities undertaken during the current phase. Deliverables and knowledge gained during commissioning during the current phase must be transferred to those involved in the next phase. This transference of knowledge may take place during a single meeting, series of meetings, or other methods of communication as decided by the owner or commissioning team. However, it involves communication in two directions. For the acceptance process at the end of the Planning and Design Phase, those with commissioning responsibilities in the Construction and Installation Phase must indicate that they understand how deliverables such as the OPR, BoD, CDs, etc., are to be used in commissioning during construction and installation. Equally importantly, those same people must raise any concerns they have if they feel commissioning cannot be implemented as specified. For example, for a particular project it may be the responsibility of the refrigeration contractor to install refrigeration systems per the OPR and BoD, insuring that the system once completed is able to be commissioned. However, if the contractor believes that certain of the owner’s requirements in the OPR cannot be met based on site constraints, the contractor must raise this issue during the acceptance process if he/she has not done so already. If necessary, the documentation should be updated to reflect any inconsistencies identified during acceptance. It is particularly important that the issues log be transferred from one phase to another because it helps prevent problems from reoccurring and time and resources from being spent solving the same problem multiple times (or correcting problems at a later date when it is more costly to do so). Every effort should be made to close out issues in the issues log that are outstanding at the end of one phase before moving on to the next phase. Finally, the owner and those with future commissioning responsibilities should indicate their formal acceptance of the deliverables and other activities during the Planning and Design Phase. Ideally, this acceptance should be in writing, with the date and name of the person accepting recorded. An example acceptance plan is shown in Appendix C.

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3 Commissioning during Construction and Installation

INTRODUCTION Objectives

The objectives of commissioning during construction focus on realizing energy and life-cycle cost expectations through the proper installation of critical systems and components. Proper planning will deliver the project on time and on budget and provide opportunity to properly commission the refrigeration system(s). This chapter provides guidance to ensure that each installed system is commissionable and will achieve the goals defined in the Owner’s Project Requirements (OPR). Owners of refrigeration systems are encouraged to incorporate a commissioning plan into their projects as described in Chapter 2, and each project team should use the steps in this chapter to prepare an installation for commissioning activities. Key areas on which to focus commissioning efforts during construction include procurement of the refrigeration equipment and proper installation of the refrigeration piping and energy management systems (EMSs). Proper procurement of equipment ensures that the specifications are met, that submittals match the construction document (CD) requirements, and that the commissioning intent of the design can be carried out. Proper installation of piping and EMSs enables the commissioning authority (CxA) to fully perform the functions detailed in the Commissioning Plan and ensures a clean handoff to the Start-Up and First-Year Operation Phase of the project. Many commissioning opportunities may be missed if a step is overlooked or if the quality of the installation isn’t monitored. Commissioning during the Construction and Installation Phase of a project allows the owner the opportunity to operate the refrigeration system at a more efficient level and ensures long-term reliability and efficiency.

Process

The Construction and Installation Phase of a refrigeration project implements the scope as outlined in the OPR, Basis of Design (BoD), and CDs and prepares the project for start-up and final commissioning. The following items should be commissioned or involve commissioning activities during this phase: • Project plan review, prebid conference, requests for information (RFI), and updates

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

“FORGOTTEN” INSTALLATION ISSUES Seemingly minor omissions or errors during equipment installation can lead to significant problems and/or inefficiencies that can last for the life of the facility. Example: Most low-temperature display cases require wiring to transfer a signal from the case to the energy management system (EMS) to terminate the defrost cycle when the evaporator is free of frost (rather than running the full default period for the defrost cycle). If this wiring is specified in the CDs but is overlooked during equipment installation, the defrost cycle may run longer than it should, increasing energy consumption, potentially risking product integrity, and possibly creating other problems. It is relatively effortless to run this wiring during equipment installation, but running the wiring after the store opens is much more difficult as it can disrupt sales and/or interfere with other maintenance operations. The owner may not even allow the work to be done, especially during the busy days or weeks following the grand opening. As a result, this problem could go uncorrected for the life of the equipment. Associated Costs: In an example where a supermarket has three runs of glass-door frozen food/ice cream cases with 30 doors in each run, the total defrost electrical load is 63 kW. The defrost runs on average 15 minutes longer each day because the termination wiring was not installed. If the power cost is $0.10/kWh, the additional costs each year for this single omission would be $575.00. 63 kW/day × 0.25 h/day × 365 days/yr = 5749 kWh/yr 5749 kWh × $0.10/kWh = $575.00/yr Translating this to grocery sales equivalent means that a store would have to sell an additional $34,000.00 worth of groceries to cover this cost! When coupled with other possible oversights, the annual costs of overlooked installation issues can grow significantly and continue for the life of the facility.

• Negotiation/bidding for prime contractors and subcontractors • Procurement requirements of refrigeration equipment and controls, including the EMS, as well as review and acceptance at delivery • Assembly of the construction team and project schedule planning • Installation of the refrigeration system, including display cases, compressor racks, condensing units, controls (including EMS), interconnecting piping, electrical wiring, and other related components • Various testing and installation verifications • Pre-start-up quality control (QC) and readiness • Installation final commissioning and review Figure 3-1 details activities related to commissioning during the Construction and Installation Phase. Activities may vary depending on the nature of the project.

Roles and Responsibilities

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Table 3-1 shows an example of commissioning roles and responsibilities during the Construction and Installation Phase. This table is an example of an owner-specified project where the owner provides a substantial portion of the requirements and specifications to the designers and contractors (as opposed

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3 ~ Commissioning during Construction and Installation

Figure 3-1 Construction and Installation Commissioning Flowchart

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Table 3-1 Example of Roles and Responsibilities Matrix in the Construction and Installation Phase for an Owner-Specified Project Role

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Responsibilities in the Construction and Installation Phase

Owner or Owner’s Representative

• Review, approve, and disseminate any changes in BoD, OPR, Commissioning Plan, CDs, sequence of operations (SoO), and systems manual and accept deliverables. • Determine what method will be used to commission the project. • Remain involved throughout the process, including scheduling, project management, interfacing with the CxA, contractors scheduling, equipment procurement, etc.

Commissioning Authority (CxA)

• Communicate Commissioning Plan to the construction team so all are aware of the commissioning structure. • Make site visits and inspections and provide documentation of the inspections as required in the Commissioning Plan. • Review OPR, BoD, CDs, SoO, and product/equipment specifications. • Communicate changes discovered during the commissioning process as relates to the BoD, OPR, Commissioning Plan, CDs, and SoO. Escalate deviations to the owner so that appropriate action is taken to correct any deficiencies that do not have prior approval.

Refrigeration Designer (Engineer of Record)

• Provide updates or changes in BoD, CDs, and SoO that occur during the requests for information (RFI) or construction process. • Review and approve product/equipment submittals.

Refrigeration Contractor and/or Installer

• Provide feedback to the design team on the project documents where conflicts exist or field modifications are required. • Review systems manual so that the installation is executed in concert with the commissioning requirements. • Resolve issues and update issues log, documenting what actions were taken, when each item is complete, and whether the issue is closed. • Install refrigeration systems per the OPR, BoD, and CDs, ensuring that the completed system can be commissioned. Record testing events and provide evidence to the CxA that all pertinent criteria have been met.

Refrigeration Original Equipment Manufacturers (OEMs)

• Supply equipment per the CDs and the project schedule requirements. • Provide operation and maintenance information for the systems manual. • Participate in any on-site inspections after equipment arrives on site as required in the owner’s equipment solicitation.

Control System Contractor

• Install controls per the CDs. • Ensure that all controls can be commissioned as defined in the CDs.

Controls Systems Programmer (if Required by Owner)

• Provide EMS programming to support the refrigeration and HVAC equipment as defined in the CDs. • Coordinate with the OEM programming that may be included and shipped as part of the refrigeration or HVAC systems.

Facility Operations and Maintenance Staff

• Provide input on site information, OPR, and BoD.

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3 ~ Commissioning during Construction and Installation

to a design-build project, where the owner may provide minimal detail in the requirements). An example of a full roles and responsibilities matrix for all phases in one table is provided in Appendix A.

INSTALLATION PLANNING AND SCOPE OF WORK

As detailed in Chapter 2, each project has a unique set of requirements that are defined in the CDs, with the OPR and the BoD providing the highlevel requirements of the owner that support the final CDs. Various components and assemblies may be detailed in the CDs during a project’s Planning and Design Phase that the installing contractors are responsible for evaluating and estimating the installation costs of during the Construction and Installation Phase.

Understanding the Project Scope

It is critical that all parties associated with the Planning and Design, Construction and Installation, and Start-Up and First-Year Operation Phases review the final documents and specifications at the start of the Construction and Installation Phase and have a thorough understanding of the project scope for bidding purposes. By following the processes detailed below, the owner will ensure that each bidder has a full understanding of the project documents and what is required for commissioning of a system. • Ensure that there is a thorough understanding of the CDs, Commissioning Plan, and owner’s requirements. • Establish a communications loop and a feedback process for plans and documents, equipment issues/questions, field changes, and site coordination as well as owner-generated changes. This allows all parties to submit questions and receive answers from the Engineer of Record, owner, etc. • Submit and document all RFI related to the project documents, ensuring that there are no questionable or gray areas within the documents and that feedback is incorporated into the planning process or OPR. • Become familiar with equipment submittals and criteria in the project documents relating to the commissioning scope. Submittals may be provided for items such as compressor racks, condensers, control systems, etc.

Contractor Negotiations and Contract Placement

The owner should ensure that prospective refrigeration installation contractors are clear about the project scope and what aspects of the project will affect commissioning of the system. The owner should also ensure that the prospective refrigeration installation contractors have the proper qualifications to execute the project. All commissioning options would require a specific scope to be detailed in the Commissioning Plan. Some suggested project bidding and/or negotiating points to consider include the following: • The owner should prepare a written document detailing the scope of work for the contractor(s). The contractor(s) should provide the owner written proposals detailing the costs, schedule, exclusions, etc. The installation and commissioning proposals should reference the current project documents and specifications, submittals, and any addenda. • The owner may choose to exempt some portion of the construction/ commissioning requirements from the contractor’s scope. These

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

IS COMMISSIONING REQUIRED BY CODE? The answer is yes. ANSI/ASHRAE/IES Standard 90.1 (ASHRAE 2013b) and the International Energy Conservation Code (ICC 2012a) both require commissioning for certain systems within a building. In the green building codes and standards that are increasingly being developed and adopted, full building commissioning is generally required. The International Green Construction CodeTM (ICC 2012b), which includes ANSI/ASHRAE/USGBC/IES Standard 189.1 (ASHRAE 2011) as an alternate compliance path, requires commissioning for buildings that exceed 5000 ft2 (464.5 m2).

Building Codes that Require Commissioning

In 2011, California adopted the California Green Building Standards Code (CALGreen), which can be adopted by local jurisdictions (CA 2013a). CALGreen includes many new requirements pointed at enhancing current codes, including provisions for adopting the most energyefficient technologies available. The code requires building commissioning for new buildings 10,000 ft2 (929 m2) and larger and specifies that commissioning be performed by trained personnel who have experience on projects of comparable size and complexity. The intent of the commissioning portions of these codes is to save energy and build better buildings. Many of the processes outlined in this Guide are required, including the Owner’s Project Requirements (OPR), Basis of Design (BoD), Commissioning Plan, criteria for functional performance testing and documentation, and a final report upon completion that certifies all criteria have been met.

commissioning related items should be clearly identified in the CDs so that the owner has a clear definition to manage by and so all parties have a clear understanding of their responsibilities. • A prebid conference or site meeting is recommended between the owner, Engineer(s) of Record, CxA, local authorities, and the general contractor and various specialty trade contractors as required. The

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3 ~ Commissioning during Construction and Installation

meeting should address the items discussed in the Understanding the Project Scope and the Project Schedule sections of this chapter. • Face to face meetings with contractor(s) should be held for all paries to clarify and agree upon outstanding items such as exceptions made to job specifications and plans by the contractor(s), any proposed supplements to the job specifications, and any other discrepancies between the job specifications and the proposal(s) by the contractor(s). • Communication protocol should be established between all parties to handle feedback on the design during construction and issues resolution. This protocol should be in place from the time the contract is signed until the work is complete and the refrigeration system is turned over to the owner.

Equipment Procurement

A properly commissioned project is affected greatly by the specifications based on performance metrics for the refrigeration and EMS equipment being supplied. The owner’s equipment specifications and submittals should match project documents and represent the owner’s desired energy consumption levels as well as control functionality. Careful review of these documents by the owner and the suppliers will ensure that commissioning can be executed to expectations. All reviews should also consider the BoD, as it sets the tone for the owner’s objectives. The following items are important to consider during equipment procurement and delivery activities: • Include the equipment commissioning scope in the request for proposal (RFP) for each major equipment vendor where commissioning applies. Vendors should incorporate the spirit of the final commissioning objective into their deliverables. This includes providing service manuals, training manuals, etc. verifications of factory-tested items, and any other field supporting documentation. • Define the submittal review process in the owner’s RFP. Rack systems and controls require a higher degree of complexity, so the submittal must be in sufficient detail to ensure the intent of the plans and specifications is included and that there has been good coordination between documents and design entities. • Include an on-site inspection for product integrity, damage repair, and proper installation of compressor systems, cases, condensers, and coils as they relate to submittal documents and design criteria. This ensures delivered goods match the project documents. Inspection responsibilities are defined by the owner in the CDs. A compilation of information from equipment manufacturers is referred to in this document as a systems manual and would be part of the project documentation.

Construction Scheduling

Commissioning within the construction schedule requires transparent coordination to ensure that all critical path processes, project communications, trades coordination, and out-of-scope cost impacts are considered and incorporated. It is important that the time required to execute each step of the commissioning process during construction be built into the schedule and be managed by the refrigeration contractor and the CxA. Certain commissioning tests have minimum time requirements or require performance approval. For

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

example, one commissioning test with a minimum time requirement is system pressure testing, which requires a 24 hour pressure test. A performance approval example is the inspection of vacuum level after the system has held the specified vacuum for the required period of time.

Project Schedule

The owner and/or general contractor is usually responsible for the development of the project schedule. The CxA should participate in the development and/or review of the project schedule to ensure the following items are incorporated: • Key milestone dates that relate to the commissioning process. • All parties who will participate in the process, including the equipment designers, equipment suppliers, various contractors, and others involved with the construction process. • A clear understanding of the role of each entity involved in the project. Table 3-1 provides example roles and responsibilities during the Construction and Installation Phase. The project schedule should also allow for the cross-check of HVAC operating setpoints and equipment schedules with the installation schedule to understand how they affect refrigeration and EMS installation and how to effectively commission the refrigeration system.

Schedule Allowances to Execute Specific CommissioningRelated Items

Each construction-related commissioning item has a time requirement for execution. These commissioning tasks should be spelled out either by including specific details in the specifications or via reference to an outside document. The following example on system pressurization illustrates one way to reference information from an outside document. In this case, if following GreenChill Best Practices Guideline: Commercial Refrigeration Leak Prevention & Repairs (EPA 2011a), there is a requirement to pressure test a minimum of 24 hours, plus any time required to set up the test. Therefore, the language in the specifications might include: Time should also be allowed to leak check in the event the pressure test does not pass. Refrigeration system field evacuations usually are a three-part process. Each has a vacuum level component, and typically the last of the evacuations has a time component as detailed in GreenChill Best Practices Guideline: Commercial Refrigeration Leak Prevention & Repairs. Schedule information would need to be customized for each project. Some items can be validated in parallel with normal installation schedules, such as verification of line sizes, review of proper installation techniques (brazing, pipe installation, use of nitrogen, etc.), and checking of EMS wire labeling. Items that may require re-work, such as replacement of piping or fittings due to lack of nitrogen purge, must be expedited so as to not impact the project schedule. The installation of a commercial or industrial refrigeration system involves many details and parallel functions, so it is important for successful commissioning during construction to be well coordinated with the project schedule and that any deviations be communicated to the general contractor, owner, or CxA.

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3 ~ Commissioning during Construction and Installation

SAFETY CONSIDERATIONS DURING COMMISSIONING Safety in the construction work place is of the utmost importance. Many of the activities described in this Guide involve the safe operation of equipment and the need to ensure that owners, operators, and customers are able to work or shop within a safe environment. The users of this Guide are strongly encouraged to study, understand, and practice all of the necessary safety codes and regulations (local, city, and state), Occupational Safety and Health Administration (OSHA) and ASHRAE guidelines, and other safety documents that may apply to the mechanical systems being commissioned. It is a generally accepted practice during the commissioning process to note and escalate any unsafe conditions to the owner or owner’s representative or the project team and to ensure that the unsafe conditions are corrected.

PREFUNCTIONAL TESTING AND VERIFICATION

The testing and verification part of the project allows the owner to have confidence that the systems are at a state that allows commissioning during start-up to take place. Proper pressure testing ensures that the piping system and equipment are leak free and ready for evacuation and charging. Proper evacuation procedures ensure that the system is free of moisture and can function at its peak efficiency when charged and started. Verification of all sensors, controls, programming, and installation functions ensures that the BoD is implemented as intended through the project design documents.

Install to Allow for Commissioning

The installation of commercial and industrial refrigeration equipment and the ability to properly commission it are dependent on following proper installation techniques as well as incorporating the correct compliment of components and interconnecting systems that allow commissioning to take place. The project documents are the basis for all necessary specifications, equipment requirements, and installation details. The CxA is responsible for ensuring that all specifications and reference documents are followed completely. The Key Installation Methods sidebars in this chapter provide some specifics of proper installation for each discipline but are not intended to be all inclusive.

Critical Steps in Prefunctional Testing and Verification

One of the critical steps in the commissioning process is the verification that the testing and evacuation of the refrigeration system was done properly. This is a multiple-step process for the CxA that takes place over multiple days. The CxA needs to be familiar with the plans and specifications as they relate to testing and evacuation. One of the best guidelines for this process is the U.S. Environmental Protection Agency (EPA) GreenChill Best Practices Guideline: Ensuring Leak-Tight Installations of Commercial Refrigeration Equipment (EPA 2011b). Some of the key items for the CxA to check are the following: • Pressure testing for leaks • Preevacuation setup • Stairstep evacuation process • Charging of the system • Final leak check

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

KEY INSTALLATION METHODS—REFRIGERATION This sidebar provides a list of key installation methods for refrigeration systems and supplies illustrations of proper and improper installations. • Use a dry nitrogen purge during the brazing process, minimizing oxidation inside of the piping. • Ensure proper slope and line supports for overhead piping, allowing oil return to the compressor rack. • Employ proper underground piping techniques. • Use proper materials for the application (copper tube type, long radius elbows, etc.). • Ensure proper drain line piping from the condenser to the receiver. • Ensure the installation of access ports at high points and in cases for superheat measurement. • Pressure test all assembled and brazed piping to 300 psig (2069 kPa gauge) for 24 h. • Evacuation techniques as detailed in the U.S. Environmental Protection Agency (EPA) GreenChill Best Practices Guideline: Commercial Refrigeration Leak Prevention & Repairs (EPA 2011a).

Photograph courtesy of Don MacLeod

Photograph courtesy of Source Refrigeration and HVAC

Illustrations of the Effect of a Nitrogen Purge when Brazing

Photograph courtesy of Don MacLeod

Photograph courtesy of NREL; credit Paul Torcellini

Improper Piping Supports (left) and Proper Piping Support System (right)

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3 ~ Commissioning during Construction and Installation

Photograph courtesy of Don MacLeod

Photograph courtesy of NREL; credit Paul Torcellini

Properly Mitered Insulation Joints (left) and Proper Overhead Supports at Change in Direction (right)

Photographs courtesy of NREL; credit Paul Torcellini

Proper Intermediate Riser Traps (left) and Improper Overhead Piping Supports (right)

Photographs courtesy of Don MacLeod

Proper (left) and Improper (right) Underground Installation

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Photograph courtesy of NREL; credit John de la Rosa

Photograph courtesy of Source Refrigeration and HVAC

Improper Condenser Drain Piping (left) and Improper Split Condenser Piping (right)

Photographs courtesy of Don MacLeod

Improper Condenser Piping with No Access Port (left) and Proper Piping with Access Port (right)

Systems that do not receive proper testing and evacuation processes will have maintenance problems and leaks during the life of the equipment. Such situations as ice forming in expansion valves, wax buildup in the system, acid in the oil, and irregular system operation are all signs that a system was not tested and evacuated properly. The vacuum pump connection illustration in Figure 3-2 provides one approach for attaching a vacuum pump to a commercial rack system through hard piping. This method gives the technician the best possible connection and will provide the quickest pulldown.

Pre-Start-Up and System Quality Control

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The pre-start-up and system quality control (QC) functions during the Construction and Installation Phase ready the refrigeration system for the Start-Up and First-Year Operation Phase of a project. The activities included during this portion of a project ensure that the system is ready to run in all aspects. Specific tasks include checks related to electrical high-voltage and low-voltage wiring, satisfaction of local inspection authority requirements, installation of EMSs, completing the refrigeration piping system, pressure testing and evacuation, and documenting changes to the initial project plans

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3 ~ Commissioning during Construction and Installation

Graphic by Lynne Schuyler, Source Refrigeration

Figure 3-2 Illustration of Vacuum Pump Connection to a Commercial Refrigeration Rack System

that have occurred through the Construction and Installation Phase that may reflect on the Start-Up and First-Year Operation Phase. Some key items to consider during a pre-start-up function include the following: • The project CDs and Commissioning Plan determine who must participate in a pre-start-up function; those typically involved include the electrical contractor, low-voltage electrical contractor (or EMS contractor), refrigeration contractor, CxA, the owner, and the Engineer of Record. • The Commissioning Plan states the responsibility of each entity at the pre-start-up evaluation. • All responsible parties should be at the pre-start-up evaluation and ready to perform their functions. • Before starting the system, each entity should sign off on the procedures that they are responsible for, such as the following: • Confirmation that the refrigeration system is ready to start. This includes verification that oil is charged, that vacuums are broken with proper refrigerant, and that power and control wiring are complete. ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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KEY INSTALLATION METHODS—ENERGY MANAGEMENT This sidebar provides a list of key installation methods for energy management systems (EMSs) and supplies illustrations of proper sensor installations. • Verify proper power, communications, and control wire routing. • Properly install all wiring, cables, wire labels, grounding, and sensor connections, as well as provide correct materials. No splicing is allowed, etc. • Locate sensors as per design, with proper mounting and accessibility. • Provide sensor road map and labeling.

Photographs courtesy of Don MacLeod

Proper Transducer Mounting (top), Walk-In Sensor Mounting (bottom left), and Outdoor Air Sensor Installation (bottom right)

• Confirmation that the HVAC system is operating and that the temperature and relative humidity are within design specifications. • Confirmation that all control valves in refrigerant piping are powered and that cases are ready to receive cooling.

CONSTRUCTION AND INSTALLATION DETAILS 50

Many actions in the Construction and Installation Phase must be executed correctly to ensure satisfactory refrigeration system operation. Many of these details are presented in the following subsections for guidance to the contractor, CxA, or owner to verify that key items related to commissioning are prop-

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3 ~ Commissioning during Construction and Installation

erly installed. Proper commissioning should include reference to each manufacturer’s installation requirements and start-up checklists. This list is by no means includes all critical details but is rather a guideline to capture the bulk of the critical installation issues in a typical refrigeration project. These critical details are presented here in basically the chronological order in which they would normally occur during a typical construction/installation of a refrigeration system: site preparation; installation of hangers, piping, and insulation (refrigerant, water, and drain piping); setting of major equipment components, conduit, and wiring; and instrumentation, testing, evacuation, and charging.

Site Preparation

Critical issues in site preparation include proper supports for condensers (i.e., level and adequate strength); satisfactory and level bases/foundations for rack systems, cases, and walk-ins; satisfactory routing and adequate building steel to support piping and conduit; proper provision for underground piping; and proper protection for piping, whether it is steel, copper, acrylonitrile butadiene styrene (ABS) or polyvinyl chloride (PVC). Note that seismic supports may be required on some jobs.

Major Equipment

All major equipment (condensers, compressor rack systems, cases, walkins) must be set level and secured structurally according to the CDs.

Condensers

Critical details for condensers include verifying that piping slopes to the condenser and back toward the rack, all fans are operational, access points are installed at the high point in discharge line piping, and all split condenser piping is installed according to the CDs to allow proper flow to each section of the condenser as well as pump out refrigerant when in “winter” mode. If condenser refrigerant liquid outlet piping is to be reduced according to the CDs, it should be reduced in the vertical drop rather in the horizontal, as the latter may cause liquid backup into the condenser. If evaporative condensers are used, water treatment should be installed and functional before start-up and operating according to specifications. Also, ensure water piping is protected from freezing.

Racks

Critical details for refrigeration racks include verifying that electrical connections/lugs are tight, checking that precautions have been taken to prevent copper rub through, and ensuring that all rack components have been leakchecked and that piping and valves are properly insulated and labeled/tagged according to the CDs.

Refrigerated Fixtures

Critical items for refrigerated cases include verifying that they are shimmed with appropriate materials and are set level and straight and that case joints and case penetrations are properly sealed according to manufacturer’s recommendations and/or CDs. Verify that proper access points for superheat measurement are present, including pressure taps along with necessary valves, controls, and strainers. Verify that case anti-sweat heaters operate as specified and that heaters cycle (where applicable) and are on their own circuit (not tied to fans or lights). Verify that case drains are piped properly, free from leaks, trapped, supported, and piped to hub/sink as specified (water is not draining on the floor). Further critical items to be checked include that fixtures are labeled according to the CDs; that seismic bracing is in place as

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

KEY INSTALLATION METHODS—EQUIPMENT This sidebar provides a list of key installation methods for equipment and supplies illustrations of proper and improper installations. • • • •

Level and seal cases. Level and secure compressor systems and adhere to proper safety and electrical clearances. Level and secure condensers. Install walk-ins per CDs and seal per Technical Procedure 9, Minimizing Air Infiltration of Boxes and Cases, in Appendix D of this Guide. • Provide glycol system access points for venting and hydrostatic testing.

Photograph courtesy of NREL; credit John de la Rosa

Photograph reprinted with permission

Improper Condenser Support Methods

Photograph courtesy of NREL; credit John de la Rosa

Properly Supported Condenser

Photographs courtesy of Don MacLeod

Improperly Sealed (left) and Properly Sealed (right) Walk-In Line Penetrations

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3 ~ Commissioning during Construction and Installation

required by local authorities; that the under-case return air system is in place, is sealed, and does not impede normal case operation; and that door closures are operable on reach-ins.

Walk-In Boxes

Critical details for walk-ins include verifying that box penetrations (refrigeration, fire sprinkler, electrical, plumbing) have been sealed according to specifications. Additional details include verifying that all panel seams are tight and free from air leaks, all door gaskets/seals are installed and operate as intended, door heaters and heated air vents are wired and functional, door switches are wired and are operational, and fans and refrigeration shut off when doors open (typically in freezer walk-ins only). Checks should be made to verify that proper access points for superheat measurement are present along with necessary pressure taps, valves, controls, and strainers. Drain lines in walk-ins that operate at or below freezing should have heat trace and insulation installed. A check should be made to verify that regulations are followed with respect to local mechanical codes, fire codes, etc., in terms of penetrations and safety requirements.

Refrigerant Piping

Critical details for refrigerant piping include verifying that all piping is the correct material specified in the CDs (could be types L/AC&R or K), that all line sizes and pipe thicknesses are in accordance with the CDs, and that brazing piping joints are made in accordance with the CDs. The CDs typically will call for all brazing processes to use silver alloy solders for the proper application and incorporate a dry nitrogen purge during brazing. Verify that piping is pressurized and tested, piping is evacuated and the vacuum is held for the required time period, piping is supported as required, pipe saddles are installed, pipe is tied down and supported at changes in direction, and appropriate expansion loops are installed as required—all of these should be completed in accordance with the CDs. Verify that seismic supports are in place as required by local authorities. Verify that oil traps have been avoided wherever possible in all refrigerant lines. One exception is P traps called for in suction risers. If a trap is unavoidable, a system design expert should make sure that there is minimal risk of

VACUUM MEASUREMENT—KEY ISSUES Proper vacuum measurement is a critical step in understanding whether a refrigeration system is ready for operation. The most current type of gauge available uses electronics and a digital readout. Older versions require a transducer sensor and include an analog indication of vacuum level. A manifold gauge set is not recommended for determining vacuum level. Vacuum should be read at the farthest possible point form the vacuum pump after the pump has been shut off for the period of time indicated in the specifications. Gauges are sensitive instruments and should be calibrated on a regular basis. There is no compromise for a good vacuum in terms of system integrity. The best advice for a technician with respect to evacuating a refrigeration system is to have patience. Rushing this process has a high risk of improper system operation in the future.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

potential damage or recommend a corrective change through the established issue resolution procedures. Critical details on suction piping include verifying that the return lines to the compressors slope downwards toward the rack systems for oil return and that suction risers, double pipe risers, and P traps are installed as called for in the CDs to facilitate oil return. Verify that purge valves have been installed at high points in condenser piping, that hot-gas defrost piping is sloped as called for in the CDs, and that liquid tees are taken from the bottom of the main liquid line.

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Underground Piping

Critical details for underground piping include verifying that refrigerant piping is pressurized, tested, and evacuated before burying as detailed in CDs. Verifying that underground piping is insulated and protected and that surrounding materials are safely backfilled as required by the CDs is of primary importance with respect to the longevity of the piping system.

Pipe Insulation

Details critical to pipe insulation include verifying that the correct type and thickness of insulation is applied according to the CDs and that subcooled liquid lines, as well as any other indoor liquid lines that will under any circumstances operate at a colder temperature than the room air dew point, are insulated in order to prevent condensation on the pipe and possible drippage. Verify and compare all insulation practices and techniques to the intent of the CDs.

Energy Management System (EMS)

There are many critical details in commissioning the EMS. Some of the more important items include verifying that wire size/type is according to specifications, that all cables are tagged and labeled at both ends, that controllers are powered up and the program is present, and that remote communications are in place (phone, internet, etc.). Additionally, verify that sensors are connected to the proper terminals and that proper installation techniques have been used for field-installed sensors. Examples of sensors include the following: • Outdoor air sensors • Indoor and outdoor humidity sensors • Refrigerant detectors • Walk-in and case temperature sensors • Remote transducers (glycol end of loop) • Drop-leg sensors

Cases/ Walk-In Boxes

Critical EMS details for boxes include verifying that certain systems are labeled in the controller as specified, offsets have been programmed as necessary, electronic evaporator pressure regulators (EEPRs) are properly programmed and mechanical evaporator pressure regulators (EPRs) are properly set to control case temperatures, and defrost times have been set according to the CDs. Departures from the CDs as they relate to defrost settings requires prior approval from the Engineer of Record/CxA/owner. Verify that lowtemperature defrost has been programmed for off-peak hours (where applicable), that all necessary defrost termination wires have been run and terminated, and that all systems are making temperature (at or above the design suction temperature) as specified on the refrigeration schedule.

Racks

Critical EMS details for racks include verifying that floating suction and head pressure are set up, racks are labeled as specified, offsets have been pro-

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3 ~ Commissioning during Construction and Installation

grammed as necessary, all systems are making temperature (at or above the design suction temperature) as specified on the refrigeration schedule. Antisweat heaters cycle where appropriate, and heaters are on their own circuit (not tied to fans or lights).

Condensers

Critical EMS details regarding condensers include verifying that floating head pressure is set up (as applicable), fans run in the correct direction, and fan controls (variable-frequency drives [VFDs] or fan cycling controls) are programmed and operating according to programming criteria. Pumps and water flow alarming should be in place and functional (for evaporative condensers or cooling towers).

FINAL INSTALLATION COMMISSIONING AND REVIEW

After a refrigeration system is determined to be “ready to start-up,” there can be a final review of all aspects of commissioning associated with the project to date. Depending on the scope of the project, this step may simply be a review that all applicable steps required during construction are complete and that documentation of those steps is ready for the next phase of the project, start-up of systems. It is also during this juncture that feedback can be given to the Engineer of Record, the owner, equipment suppliers, or others involved in the project to report on items that deviated from the CDs, to provide suggestions for improvement on future projects, and to identify opportunities that were missed or were compromised, etc. If necessary, the systems manual and its constituent documents should be updated. Positive feedback regarding the installation of the refrigeration system and EMS allows the owner’s project team to have a higher comfort level that the system as installed can be fully commissioned per the Commissioning Plan.

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4 Commissioning during Start-Up and First-Year Operation

INTRODUCTION Objectives

The objective of commissioning during the Start-Up and First-Year Operation Phase is to verify that the refrigeration system is properly started and that it operates as intended per the Owner’s Project Requirements (OPR) and the Basis of Design (BoD). While verifying proper installation of the system is not a direct objective of this phase, installations issues uncovered during the commissioning process will need to be addressed. Performing additional commissioning activities after start-up during the first year of operation, which corresponds to the typical equipment warranty period, helps owners identify and resolve performance problems within the warranty period. Another reason to continue with commissioning activities through the first year, or longer, is because it is not possible during start-up to verify system performance under all conditions—including outdoor ambient extremes and the full range of cooling loads. Additionally, some performance problems may become apparent only after the refrigeration system has been operating for a period of time.

Process

Commissioning during system start-up generally commences after all equipment and controls for the refrigeration system have been installed, the refrigeration system has been evacuated, and enough refrigerant is added to break the vacuum. All other construction and installation commissioning activities should also be complete at this time. These are the obvious prerequisites for commissioning during the Start-Up and First-Year Operation Phase. Less obvious are the quality control (QC) measures that should be taken by the refrigeration contractor to make sure that the system handed over to the startup crew has been installed correctly and per the construction documents (CDs). Commissioning during start-up and the first year will primarily focus on the operation of the system and less on the installation of the system. Significant operational issues that are not discovered until start-up can cause major disruptions. Chapter 3 includes several recommendations for pre-start-up tests, verifications, and QC measures. These activities are prerequisites for the Start-Up and First-Year Operation Phase. Figure 4-1 details activities related to commissioning during system startup. Activities may vary depending on the nature of the project.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Figure 4-1 Start-Up Commissioning Flowchart

Roles and Responsibilities

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Table 4-1 shows an example of commissioning roles and responsibilities during the Start-Up and First-Year Operation Phase. This table is an example for a project that is largely owner specified, with the owner providing many of the system specifications to the refrigeration designer and contractors (as opposed to a design-build project, where the owner may provide minimal

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4 ~ Commissioning during Start-Up and First-Year Operation

Table 4-1 Example of Roles and Responsibilities Matrix in the Start-Up and First Year Operation Phase for an Owner-Specified Project Role

Responsibilities in the Start-Up and First-Year Operation Phase

Owner or Owner’s Representative

• Approve modifications to the OPR or Commissioning Plan if required based on feedback from the commissioning process. • Resolve disputes regarding responsibilities for corrective action. • Decide what corrective measures will be implemented when measures are optional or when multiple options exist.

Commissioning Authority (CxA)

• Coordinate commissioning activities. • Monitor systems testing and operational functional performance tests (FPTs). • Observe testing process and document test results. • Coordinate with the owner, Engineer of Record, and contractors to find solutions to discrepancies or malfunctions uncovered during the commissioning process. • Document corrective actions taken. • Retest as necessary to validate the results of the modifications. • Document recorded benchmarks as defined in the OPR and/or Commissioning Plan.

Refrigeration Designer (Engineer of Record)

• Provide resolutions for any discrepancies discovered. • Adjust project documents and sequence of operations (SoO) as necessary to reflect final commissioned conditions.

General Contractor

• Support commissioning activities by various trades as needed to operate equipment. • Verify corrective measures have been implemented.

Refrigeration Contractor and/or Installer

• Perform start-up, tuning, and adjusting of system. • Perform tests as directed by CxA. • Resolve issues discovered.

Refrigeration Original Equipment Manufacturers (OEMs)

• Provide installation and operation manuals for all equipment. • Answer questions regarding equipment operation. • Resolve issues discovered.

Control System Contractor

• Perform tests as directed by CxA. • Resolve issues discovered.

Facility Operations and Maintenance Staff

• Observe commissioning process. • Provide input on how the facility will actually be operated.

detail in the requirements). An example of a full roles and responsibilities matrix for all phases in one table is provided in Appendix A.

COMMISSIONING ACTIVITIES Review Commissioning Plan

One of the first steps for the commissioning team in the Start-Up and First-Year Operation Phase is to understand the commissioning scope by performing a thorough review of the Commissioning Plan. All commissioning

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

activities needed to satisfy the OPR should be identified in the Commissioning Plan. There will be other critical information spelled out in the Commissioning Plan that the commissioning team will need to become familiar with as well, such as the commissioning schedule, documentation requirements, responsibilities, etc.

Review Warranty Requirements

The commissioning team, along with the refrigeration contractor, should also become familiar with the warranties in effect on the various systems and components. Some warranties may become void if system start-up is not conducted in a prescribed way. Furthermore, the OPR should specify all system performance benchmarks that need to be recorded and when. The warranty requirements from equipment manufacturers, contractors, and the owner’s specifications should be summarized, reconciled, and transferred to the Commissioning Plan. Some of the typical warranty requirements relate to • equipment damage during shipment and/or installation, • improper equipment installation, • equipment prematurely or improperly started up, • equipment operated outside of design conditions, • a lack of documents/records that certify start-up measurements, and • qualification/certification of contractors and start-up technicians. The inclusion of warranty requirements within the Commissioning Plan may help to mitigate voided warranties, which can result in costly repairs and possible downtime if there are premature system failures.

Verify Systems Operation

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The Commissioning Plan should include all the necessary activities required to verify that the system is operating as described in the BoD per the OPR. Following is a generic list of recommended commissioning activities for a typical refrigeration system. This list will not be appropriate for every system and should be modified to fit specific projects as needed. For more information, refer to Appendix D, which includes more detailed information on the technical procedures required to carry out some of these commissioning activities. • Verify mechanical control settings • Safety controls • Evaporator pressure regulators (EPRs) • Thermostatic expansion valve (TXV) superheat • Head pressure control valves • Verify electronic control settings • Case/circuit/walk-in temperature and pressure setpoints (at evaporators) • Compressor suction pressure setpoints • Condenser temperature and pressure setpoints • Subcooler setpoints • Case light controls • Anti-sweat controls • Verify sequence of operations (SoO) per BoD/OPR • Compressor staging • Floating head and suction pressure

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4 ~ Commissioning during Start-Up and First-Year Operation

SETTING EVAPORATOR PRESSURES WITH TEMPERATURE GLIDE There is not currently a standardized approach for setting or checking setpoints when dealing with temperature glide. The information in this sidebar is not directly related to a commissioning process but rather a commissioning activity. By providing some background information about temperature glide and discussing some of the related commissioning issues, this information may be helpful in avoiding some of the common pitfalls. Although temperature glide has been around for decades, there is still opportunity for improved design methodology and the way in which systems are set up to realize a standardized approach. With the continued use of halocarbon refrigerants there has been a shift toward the use of refrigerants with a lower global warming potential (GWP). Most low-GWP refrigerants are zeotropic and have significant temperature glide—instead of exhibiting a constant temperature during the phase change, the refrigerant undergoes a temperature drop in the condenser and a temperature rise in the evaporator. A common refrigerant used today in new commercial refrigeration systems and in R-22 retrofits is R-407a; it exhibits a temperature glide of approximately 8° in both the condenser and the evaporator (depending on the pressure). Setting or checking of superheats, subcooling, evaporator pressure regulators (EPRs), and other temperature-related setpoints throughout the system is more complicated when there is temperature glide. This is largely due to the fact that most of the industry refers to pressure by stating temperature, which works for azeotropic refrigerants because there is a direct relationship between the two at saturated conditions. For zeotropic refrigerants, however, temperature isn’t stable at saturated conditions, so stating an “evaporator temperature” or “condensing temperature” is meaningless unless the temperature is identified as a bubble-point temperature, mean temperature, or dew-point temperature. (Refer to the glossary for more information on these terms.) When setting the evaporating pressure for one or more coils, a contractor typically references the evaporator temperatures from the refrigeration CDs (or equipment cut sheets) and then converts this to a pressure that can be read with a pressure gauge at the coil. The EPR would then simply be adjusted to match this pressure. In the case of high-glide refrigerants, however, the evaporator temperatures listed in the CDs are typically not specified as bubble-point, mean, or dew-point temperatures, primarily because the case and coil manufacturers generally do not publish these values. Assuming that temperatures represent midpoint values (unless otherwise noted)

Graphic courtesy of NREL; credit Alfred Hicks

Temperature Profile of a High-Glide Refrigerant

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

is generally the best place to start to achieve the expected coil performance. However, the midpoint temperature relating to the operating pressure of an evaporator does not represent the average coil temperature. In fact, unlike azeotropic refrigerants, the inlet coil temperature is affected by the amount of liquid pressure and subcooling present upstream of the expansion valve. The figure shows the temperature profile of a high-glide refrigerant as it passes through an expansion valve, boils, and becomes superheated within an evaporator (at a theoretical constant pressure). As previously stated, the temperature at the inlet of the coil is not the bubble-point temperature. What ultimately matters is the product temperature, so many times EPRs will be adjusted to maintain discharge air temperature (DAT) instead of evaporating pressure. Contractors should use caution when applying this method, especially when attempting to troubleshoot system issues. Evaporating pressures may be driven inefficiently low by chasing air temperatures when the real issue may be a bad fan or a dirty coil.

• Condenser fan cycling, split (winter) operation, and temperature difference (TD) control • Defrost settings • Surge receiver operation • Leak detection, emergency equipment shutdown, and ventilation • Heat reclaim operation (air and water) • Internal alarms and monitoring functions • Verify or evaluate other/miscellaneous items • Monitoring functions, including data logging • Refrigeration system capacity • Part-load operation • Air infiltration into and sealing of refrigerated boxes and display cases • Vapor barriers (piping) • Excessive vibration • Proper condensate management As these activities are carried out, the commissioning team will likely uncover issues with system operation. Some of these issues may be easily remedied by the refrigeration contractor. Others may not be so easy to resolve, such as those due to poor design or those with a component for which resolution may not be so obvious. Regardless of the issue, the commissioning authority (CxA) should work with the appropriate party to help determine the most appropriate solution while keeping the owner included in the correspondence. As defined in Chapter 2, the issues log should be updated with all issues the commissioning team comes across so that the owner and other team members have the opportunity to avoid similar issues on future projects.

Training Requirements

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Another important activity that is not directly related to the refrigeration system is the verification of required training for the staff responsible for the day-to-day operations and maintenance of the refrigeration and control sys-

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4 ~ Commissioning during Start-Up and First-Year Operation

tems. As detailed in Chapter 2, this training should be specified in the OPR. The OPR should detail who delivers the training (manufacturer, owner, contractor, CxA, etc.), who receives the training (on-site and/or outside operations and maintenance staff), and what will be in the training (content and depth). Typically, the training should provide sufficient background and knowledge to enable the staff to understand the basic intended functions of the system to effectively maintain the operational characteristics and specifications of the systems. Some of the training may occur before the system is started up and some may occur after the facility is in operation. The CxA should understand the specified training requirements and verify and document at the appropriate stages of the project that the specified training has been delivered and received as intended.

START-UP REPORT AND HANDOFF TO OWNER

The start-up report is a document summarizing the commissioning work and results obtained during the start-up of the refrigeration system. The owner and owner’s technical representative should formally accept the start-up commissioning activities and report. This will ensure that the owner is aware of any problems that became apparent during start-up and is able to identify the contractor or contractors responsible for solving the problems.

Issues Log

During the transition from start-up to the first year of operation, it is important for the commissioning team to review and update the issues log. The updates should include any issues discovered during start-up, including any tests or technical procedures conducted. Given the compressed timeline often associated with starting up a commercial refrigeration system, not every issue may be able to be resolved during start-up. In such cases, the commissioning team must develop a plan for resolving the issue at a later time, ideally within the first year of operation. The owner should also review the issues log as part of the acceptance procedures and verify that he/she accepts the plans for resolving any outstanding issues.

Start-Up Report

The start-up report should document system characteristics during startup and contain the information necessary to determine whether each component is operating as intended in the BoD per the OPR; if there are any discrepancies, it should contain enough information for any issues to be resolved in the first year of operation or include an explanation of the approval granted by the owner for issues to remain unresolved, if applicable. The start-up report should include the following information: • Operating characteristics of all system components being commissioned (e.g., setpoints, gauge readings, etc.) and the ambient conditions at which the operating characteristics were documented • Outcomes of any tests and technical procedures conducted during start-up • Up-to-date issues log • Verification by the owner and any key facilities operations personnel that they have reviewed and accepted the information presented in the report

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Although system start-up is often rushed to meet deadlines for facility operation (e.g., a store opening), it is important to keep a record of commissioning activities performed. Successful start-up and proper operation can be initially verified by reviewing component characteristics to confirm that they are within the design specifications. If the energy use of the facility is to be tracked, a record of component characteristics at start-up can help establish a performance baseline for the facility. The start-up report should also include documentation of the outcome of any tests or technical procedures conducted during system start-up.

ACTIVITIES IN THE FIRST YEAR

Many of the commissioning activities during start-up may focus on one or two components and their independent operation from the rest of the system; however, the goal of commissioning is for the entire system and all its components, working together, to operate as intended. For this reason, the OPR may require that the system’s total capacity be verified or that the system’s operation during part-load and low-ambient conditions be verified. Both of these commissioning activities require several components to be in-tune and operating in concert; therefore, it is recommended that these activities be performed only after individual component operations have been evaluated. Furthermore, benchmark data should only be recorded after the system, as a whole, is operating as intended. Allowing the refrigeration system to operate for an extended period of time after start-up is important to allow proper verification of system and component performance. For example, the insulated panel of a freezer box may appear to be properly sealed at start-up but, after a month or more of operation, ice formation inside the space may become apparent—indicating poor initial panel sealing during construction. Figure 4-2 details activities related to commissioning during the first year of operation. Activities may vary depending on the nature of the project.

Document Performance Benchmarks

Benchmarking requirements are generally about documenting the owner’s expectations of the performance of the refrigeration system and how often the system will need to be serviced. These requirements should be specified in the OPR. One requirement often included in the Cx Plan is to document the acceptable operational boundaries of the refrigeration system in terms of control setpoints, anticipated electrical power consumption, estimated component/system efficiencies, and system service requirements. Some of the potential benchmark requirements may include the following: • Acceptable load temperature ranges, including load temperatures during defrost • Acceptable compressor suction temperature ranges • Anticipated condensing temperature ranges for site ambient range conditions • Expected annual system energy consumption, based on ambient range conditions • Anticipated annual refrigerant leak rate/replenish requirement • Anticipated annual service requirements Documenting the performance benchmarks of a refrigeration system provides a high level of confidence that the system is operating as intended across

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4 ~ Commissioning during Start-Up and First-Year Operation

Figure 4-2 First-Year Operation Commissioning Flowchart

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

the indoor and outdoor humidity and temperature conditions specified in the OPR and BoD. The performance data for refrigerated display cases, including recommended control setpoints, usually come from the case manufacturers. The performance data for refrigeration racks is more dependent on the designer’s choice of configuration as defined in the BoD. Among the highest-priority performance benchmarks are the temperatures that the refrigerated display cases and walk-in coolers and freezers are supposed to maintain while refrigerating and during defrost. Therefore, some measure of temperature control may be required for off-cycle defrost cases, such as defrost termination temperatures. The use of defrost termination temperatures may require additional control programming. Case manufacturers are capable of providing defrost termination temperatures and recommended locations for the temperature sensors. Another important performance benchmark is the estimated annual electrical energy consumption. The refrigeration system designer’s estimated energy consumption should be validated by submetering the power for the system. Corrections may be necessary to account for the actual indoor and outdoor temperature and humidity conditions at the time of measurement. Periodic maintenance is needed on cases and racks to ensure proper operation of the refrigeration system. These requirements should be identified within the Commissioning Plan. Measurable loss of performance may simply be associated to cleaning or service needs within the system. The system owner may request additional calculated performance benchmarks in the OPR, such as electrical use per capacity or refrigerant charge per capacity. The CxA should verify that the performance benchmarks in the OPR are incorporated into the Commissioning Plan with descriptive definitions of operating boundaries and how to measure the various benchmarks.

Evaluate System Capacity

A proper commissioning process gives the refrigeration system owner documented verification that the system is able to achieve the capacity it was designed to have on the design day (as identified in the BoD). If the CxA determines that the system capacity is not sufficient as designed to maintain product temperatures under all expected outdoor conditions, this feedback should be given to the owner to influence future project designs. Refer to Technical Procedure 2, Verifying Refrigeration System Capacity, in Appendix D for additional information and considerations when verifying system capacity. The CxA will also need to account for the load conditions when verifying system capacity. Conditions such as facility wet-bulb and dry-bulb temperatures will affect the required capacity of the system much like outdoor ambient conditions will. Additionally, facility operations, such as stocking hours and loading times, and evaporator defrost schedules will affect the capacity requirement of the system and need to be accounted for. The timing and expected conditions for when and how the system’s capacity is verified should be defined in the Commissioning Plan as described in Chapter 2.

Evaluate Part-Load and Low-Ambient Operation

Most refrigeration systems only operate at design conditions for a few hours a year. This means that there is a good chance that some of the compressors and condenser fans will not need to run very often, which reduces operating costs. The control parameters of the refrigeration’s energy management

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4 ~ Commissioning during Start-Up and First-Year Operation

ISSUES WITHIN THE FIRST YEAR—A CASE STUDY Background: A supermarket was to be built in a cold, northern location in the U.S. and the owner wished to use evaporative condensing technology for the refrigeration system. The owner’s direction was followed and the compressor rack was designed to use a close-coupled evaporative condenser that was to be located inside the compressor room and ducted through the roof. In a last-minute change, the owner decided to use a roof-mounted air-cooled condenser instead. This design change was implemented, but the compressor rack had already been built per the original design and shipped to the site. At this point, it was the contractor’s responsibility to upsize a compressor to gain the additional capacity needed to operate at higher condensing temperatures. The contractor installed the necessary head pressure control valves to maintain the system’s minimum condensing temperature in the wintertime. The system was then fully installed and started up. Problem: The store’s grand opening was scheduled for early fall and the system was installed and verified to be performing as required. As winter approached, the store personnel noticed that some of the cases were running warm. The service technician that diagnosed the issue (a separate entity from the installing contractor) noticed a low-level alarm in the liquid receiver. All the “extra” liquid in the receiver was being used to flood the condenser, which left the receiver essentially empty and starved the expansion valves at the evaporators. The service technician took the most logical step at the time, which was to fill the receiver with additional refrigerant to gain the proper levels. The result of this fix was that the system began performing as required once again. The system continued to run well until the first hot spring day. This time the service technician noticed elevated head pressures. Upon further investigation it was determined that the root issue was that the receiver on the rack was actually too small, as suggested by the fact that it was completely full of liquid. It had originally been sized for a close-coupled evaporative condenser with no allowance for flooding an air-cooled condenser (and a long drain pipe) in the winter. In the warmer months, when the condenser needed to fully drain to achieve maximum capacity, there was not enough volume in the receiver to hold the extra refrigerant that was added in the winter. Finally, the contractor upsized the receiver and corrected the issue permanently. Lessons Learned: The primary lesson to be learned is that just because the system runs well at start-up does not mean that it will continue to run well over time. Issues that arise in the first year or later will not always represent new or independent issues—many times these issues will be directly connected to the original design or installation of the system. Another observation is that there was no CxA involved in this project and that the contractor who installed and started up the system was released from the job shortly after the store opened. Knowledge of the changes during construction was lost when the contractor left, so the service technician was not able to address the root problem during his initial servicing of the system in the winter. Instead, the system was not effectively fixed in the winter, which led to both the need for additional servicing and to additional loss of product in the spring.

system (EMS) should stage the compressors and condensers to meet reduced requirements. The BoD may include a table of data or a graph of compressor capacities and thermal heat of rejection (THR) values at varying suction and discharge temperatures. If this information is not included in the BoD, it can be requested from the designer or the manufacturer and can be used to help the CxA judge how many compressors should be running based on conditions. ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Sequence of Operations (SoO)

The sequence of operations (SoO) defined in the BoD should also be verified as the system transitions from high-ambient conditions to low-ambient conditions. In other words, the order in which compressors stage, condenser fans cycle, head pressure valves open/close, etc., should be verified so that the system performance and energy usage are optimized and the system is operating as designed. Once the system reaches the lowest ambient condition there will be additional verifications required to ensure that the system is able to maintain stable operation. Many systems are designed to float suction and discharge pressures as a means to achieve significant energy savings during partload and low-ambient conditions. However, there can be some negative side effects to this control scheme that the CxA will need to check for. If the system was properly designed and installed, the CxA should not find any operational issues and may even discover that a more aggressive approach can be taken to safely save even more energy. This feedback should be provided to the owner for him/her to process and use. Refer to Technical Procedure 3, Evaluating Part-Load Operation, in Appendix D for additional information and considerations when verifying part-load operation.)

FIRST-YEAR FINAL REPORT AND ACCEPTANCE

The final report at the end of the first year should focus on the operation of the system as a whole. As mentioned previously, some operating characteristics of the system can only be evaluated under certain ambient conditions or certain load scenarios. Deliverables should be sufficiently detailed to illustrate whether the system is operating as documented in the BoD and per the OPR. The owner and owner’s technical representative should formally accept the first-year commissioning report.

Issues Log

The commissioning team should update the issues log as issues arise during the first year of operation, particularly with changes in the seasons that may affect system operation and capacity (such as that illustrated in the sidebar “Issues within the First Year—A Case Study”). Issues should be resolved as soon as possible and the issues log should be continually updated as issues are resolved. The commissioning team should consult with the facility’s maintenance and operations personnel on a regular basis during the first year to ensure that problems with the system are identified and documented.

Final Report

The commissioning team should prepare a final report at the end of the first year documenting all commissioning activities conducted on the system, including any relevant information from deliverables of previous phases, to provide the owner with complete information on the commissioning for the project. Not only will the final report help the owner evaluate the system’s performance as compared to the design, but it should also illustrate the benefit of commissioning itself by drawing attention to commissioning activities that saved energy or improved system performance. The final report’s content and format is flexible, but at a minimum the report should include the following: • All required system benchmark data per the OPR and Commissioning Plan • Expected and actual system operating characteristics at start-up and at certain points during the first year (e.g., capacity, refrigerant level, key setpoints, etc.)

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4 ~ Commissioning during Start-Up and First-Year Operation

• Outcomes of all tests and technical procedures conducted, including a summary of the data collected (e.g., system capacity, part-load operation, etc.) • Up-to-date issues log • Estimated benefit of commissioning activities, either quantitative or qualitative (e.g., case studies) • Verification by the owner that he/she has accepted the information provided in the report

THE NEED FOR SEASONAL/FIRST-YEAR COMMISSIONING—A CASE STUDY Background: A supermarket located in southern Idaho was scheduled for a grand opening in early April. The store had installed a four-compressor parallel refrigeration rack with a twelve-fan air-cooled condenser. The system was used for space comfort air-conditioning with a design saturated suction temperature (SST) of 44°F (6.7°C) and a 15°F (8.3 K) design condenser temperature difference (TD). The system employed a floating head pressure control strategy with a setpoint of 12°F (–11°C) differential between entering air temperature and saturated condensing temperature (SCT). This setpoint ensured that all of the condenser fans would be running during high-load conditions while allowing fans to be turned off during lower-load periods. The minimum SCT was set at 70°F (21°C) because of the high-temperature application and the use of scroll compressors. Problem: To meet the grand opening date, the refrigeration systems were started and commissioned during late February when the outdoor ambient temperatures were 20°F to 30°F (–6°C to –1°C). Because the ambient was so far below the minimum SCT, the setpoint was at the minimum and the fans cycled normally. During seasonal summer checks, it was noticed that the head pressure on the rack was running significantly higher than design while at the same time only one or two fans were running. Investigation revealed that the control strategy was indeed floating the head in relation to the temperature input supplied by the ambient air temperature sensor; however, the ambient air temperature sensor was mounted incorrectly and therefore was supplying inaccurate readings. The temperature sensor had been mounted on a center tube sheet beneath two fans at the end of the condenser opposite the refrigerant headers. These two fans were the last fans cycled on by the controller. As the condenser warmed, the tube sheet also warmed, which in turn warmed the ambient air sensor and thus caused the setpoint to be raised. The rising setpoint prevented the condenser fans from staging on since the setpoint appeared to be satisfied. Because the condensing pressure was increasing, additional compressors were staged on to meet the load and maintain the SST setpoint. This continued until the SCT rose to 20°F to 30°F (10 K to 15 K) above the true ambient temperature, at which time convective air currents began to cool the sensor. As the SCT continued to rise, the controller began to turn fans on. When the last two fans, beneath which the sensor was located, turned on, the temperature output from the ambient temperature sensor quickly dropped, thus dropping the setpoint and keeping all the fans on until the SCT returned to the setpoint of 12°F (–11°C) above the true entering air temperature. As the condensing temperature came down, fewer compressors were needed to maintain the SST, so compressors staged off. This all happened in very rapid cycles of from 5 to 10 minutes per cycle. The obvious consequences of these condenser pressure oscillations were increased compressor cycling, greatly increased fan cycling, and increased energy usage. Less obvious was the extra stress placed on the condenser by the rapid thermal and pressure cycling that, if left uncorrected, would eventually lead to refrigerant leaks in the condenser.

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Corrective Action: The ambient air temperature sensor was relocated to a location where it was not in contact with the condenser structural members (it was moved to beneath the first fan to be staged on). This stabilized the reading from the ambient temperature sensor, which also stabilized the condenser control setpoint. This reduced condenser fan and compressor cycling and reduced energy usage because the system was now operating at the intended condensing temperature rather than 10°F or 20°F (5 K or 10 K) higher, as it had previously.

Photograph courtesy of Timothy Gwyn, DC Engineering, PC

Improperly Mounted Ambient Air Temperature Probe

Graph courtesy of Timothy Gwyn, DC Engineering, PC

Fluctuating Ambient Air Temperature Reading Causing Condensing Pressure to Fluctuate

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4 ~ Commissioning during Start-Up and First-Year Operation

The report may also include, if relevant, the following: • Energy used by the system throughout the first year, if the system is metered separately • “Lessons Learned”—an evaluation of how the commissioning process can be improved for future installations

Flexibility with Ongoing Commissioning

First-year commissioning (if part of the Commissioning Plan) can also be part of an ongoing Commissioning Plan. This can be accomplished in a variety of ways, including the following two examples: • Employ a CxA to commission critical energy-related setpoints, system performance, and compliance to the original project BoD on an annual basis (either remotely or on site). The intent of this annual event would be verification or reset of setpoints for optimal performance. At the owner’s choice, this may also include non-energyrelated items that are key to system performance. • Other structured commissioning events may take place on a monthly, quarterly, seasonal, or an as-needed basis based on energy use excursions or other operational concerns. These events can take place either remotely or on site, or some combination of both, and typically require some feedback to the servicing contractor and owner as to what needs attention. Oftentimes the adjustments are made (if needed) on site at the time of the event. Some owners may choose to transition the commissioning needs of a site to other entities after construction is completed and the scope of the Commissioning Plan has been executed. The other entity may be in-house personnel, a servicing contractor, or a third-party company. It is up to the owner to determine the approach for ongoing commissioning that best suits the facility’s needs and budget.

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Appendix A Roles and Responsibilities Matrix

Table A-1 shows an example of commissioning roles and responsibilities during all phases of a refrigeration system project. This table is an example for a project that is largely owner specified, with the owner providing many of the system specifications to the refrigeration designer and contractors (as opposed to a design-build project, where the owner may provide minimal detail in the requirements). The information is the same as what is shown in the individual roles and responsibilities tables in Chapters 2, 3, and 4, but showing it all in one table allows for comparison of the responsibilities for a specific role throughout the project.

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Responsibilities in the Responsibilities in the Responsibilities in the Start-Up and First-Year Operation Phase Planning and Design Phase Construction and Installation Phase Owner or Owner’s • Provide Owner’s Project Requirements • Review, approve, and disseminate any • Approve modifications to the OPR or Representative (OPR), site information, financial changes in BoD, OPR, Commissioning Commissioning Plan if required based on information, and product/equipment Plan, CDs, SoO, and systems manual feedback from the commissioning specifications. and accept deliverables. process. • If desired, undertake cost/benefit analysis • Determine what method will be used to • Resolve disputes regarding of energy-saving features. commission the project. responsibilities for corrective action. • Provide direction on the extent of required • Remain involved throughout the process, • Decide what corrective measures will be commissioning to be reflected in the OPR implemented when measures are optional including scheduling, project and Commissioning Plan. management, interfacing with the CxA, or when multiple options exist. • Review and approve Basis of Design contractors scheduling, equipment (BoD), Commissioning Plan, construction procurement, etc. documents (CDs), and sequence of operations (SoO) and accept deliverables. • Identify which technical procedures must be performed as part of the commissioning process. Commissioning • Lead development of Commissioning • Communicate Commissioning Plan to the • Coordinate commissioning activities. Plan. construction team so all are aware of the • Monitor systems testing and operational Authority (CxA) • Review OPR, BoD, CDs, SoO, and commissioning structure. functional performance tests (FPTs). product/equipment specifications. • Make site visits and inspections and • Observe testing process and document provide documentation of the inspections test results. • Work with owner to identify technical as required in the Commissioning Plan. • Coordinate with the owner, Engineer of procedures that are relevant to the • Review OPR, BoD, CDs, SoO, and Record, and contractors to find solutions to project. product/equipment specifications. discrepancies or malfunctions uncovered during the commissioning process. • Communicate changes discovered during • Document corrective actions taken. the commissioning process as relates to • Retest as necessary to validate the the BoD, OPR, Commissioning Plan, results of the modifications. CDs, and SoO. Escalate deviations to the owner so that appropriate action is taken • Document recorded benchmarks as to correct any deficiencies that do not defined in the OPR and/or have prior approval. Commissioning Plan. Refrigeration Designer • Develop BoD, CDs, and SoO. • Provide updates or changes in BoD, CDs, • Provide resolutions for any discrepancies (Engineer of Record) • Review product/equipment specifications and SoO that occur during the requests discovered. and modify as needed. for information (RFI) or construction • Adjust project documents and SoO as process. necessary to reflect final commissioned • Provide input on cost/benefit analysis of conditions. energy-saving features, Commissioning • Review and approve product/equipment Plan, and systems manual. submittals.

Role

Table A-1 Full Roles and Responsibilities Matrix

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Facility Operations and Maintenance Staff

• Provide input on site information, OPR, and BoD.

• Provide input on cost/benefit analysis of energy-saving features.

Control System Contractor

Controls Systems Programmer (if Required by Owner)

• Provide input on cost/benefit analysis of energy-saving features.

Responsibilities in the Planning and Design Phase

Refrigeration Original Equipment Manufacturers (OEMs)

Refrigeration Contractor and/or Installer

General Contractor

Role

Table A-1 Full Roles and Responsibilities Matrix (continued)

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• Provide feedback to the design team on the project documents where conflicts exist or field modifications are required. • Review systems manual so that the installation is executed in concert with the commissioning requirements. • Resolve issues and update issues log, documenting what actions were taken, when each item is complete, and whether the issue is closed. • Install refrigeration systems per the OPR, BoD, and CDs, ensuring that the completed system can be commissioned. Record testing events and provide evidence to the CxA that all pertinent criteria have been met. • Supply equipment per the CDs and the project schedule requirements. • Provide operation and maintenance information for the systems manual. • Participate in any on-site inspections after equipment arrives on site as required in the owner’s equipment solicitation. • Install controls per the CDs. • Ensure that all controls can be commissioned as defined in the CDs. • Provide energy management system (EMS) programming to support the refrigeration and HVAC equipment as defined in the CDs. • Coordinate with the OEM programming that may be included and shipped as part of the refrigeration or HVAC systems. • Provide input on site information, OPR, and BoD.

Responsibilities in the Construction and Installation Phase

• Observe commissioning process. • Provide input on how the facility will actually be operated.

• Perform tests as directed by CxA. • Resolve issues discovered.

• Provide installation and operation manuals for all equipment. • Answer questions regarding equipment operation. • Resolve issues discovered.

Responsibilities in the Start-Up and First-Year Operation Phase • Support commissioning activities by various trades as needed to operate equipment. • Verify corrective measures have been implemented. • Perform start-up, tuning, and adjusting of system. • Perform tests as directed by CxA. • Resolve issues discovered.

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Appendix A ~ Roles and Responsibilities Matrix

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Appendix B Example Commissioning Plan

This appendix provides an example Commissioning Plan. In this example, a commissioning authority (CxA) has developed this plan to show the owner how he/she will commission the project. The CxA in this example is responsible for coordinating commissioning among everyone involved in this project. The information contained in this appendix may not be applicable to all projects (for example, if commissioning responsibilities are split among multiple parties rather than one CxA). Regardless of who develops the Commissioning Plan for a given project, it should be developed at the outset of the project. 1. Overview a. Purpose The purpose of the Commissioning Plan is to provide a road map for the implementation of the commissioning process. It outlines the scope of the process and describes the responsibilities of the commissioning authority (CxA) and other entities involved in commissioning. b. Objectives and Scope of Activities This Commissioning Plan covers commissioning during three phases of project development: Planning and Design, Construction and Installation, and Start-Up and First-Year Operation. Commissioning during each phase involves the following activities: Planning and Design Phase • Develop, compile, and review commissioning documentation, ensuring that all relevant system information is recorded. • Finalize scope of commissioning and roles and responsibilities. • Identify technical procedures to be conducted as part of the commissioning process. Construction and Installation Phase • Ensure that all members of the project team understand the commissioning scope. ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

• Ensure all members of the project team have access to and understand the commissioning documentation. • Conduct technical procedures and/or sections thereof that are relevant to this phase. • Update commissioning documentation as needed. Start-Up and First-Year Operation Phase • Witness a portion of the equipment start-ups to ensure protocols are followed. • Conduct technical procedures and/or sections thereof that are relevant to this phase. • Update commissioning documentation as needed. c. Equipment to be Commissioned All refrigeration systems and their associated controls will be commissioned, including the following: • Compressor rack assemblies • Condensers and enclosures • Refrigerated cases • Walk-in coolers and freezers • All built-in and external refrigeration controls • Refrigerant piping 2. Roles and Responsibilities The roles and responsibilities for this project are as follows: Role

Responsibilities

Owner

Provide the Owner’s Project Requirements (OPR). Make final decisions on how to resolve disputes that arise during commissioning. Make final decisions on any design changes.

Commissioning Authority (CxA)

Manage the commissioning process. Develop the Commissioning Plan. Facilitate communication between all parties, including organizing meetings. Compile and organize the commissioning documentation, ensure it is available to all parties, and ensure the communication of updates. Facilitate development of any new technical procedures. Develop the Basis of Design (BoD) document. Implement any changes to the design as specified by the owner and work with the CxA to ensure the changes are documented.

Refrigeration Design Team

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Appendix B ~ Example Commissioning Plan

Refrigeration Contractor

Incorporate commissioning activities into the system installation and start-up. Support the CxA in documenting system performance and testing outcomes.

Refrigeration Original Equipment Manufacturers (OEMs), including Controls Manufacturers Facility Operation and Maintenance Staff

Assist in performing commissioning technical procedures. Support the CxA in documenting system performance.

Support the CxA in developing the commissioning documentation by providing site information and system performance feedback. Complete training requirements.

3. Communications Protocols Outside of regularly scheduled meetings, the following protocols will be used on this project: Issue

Protocol

For requests for informa- The CxA goes to the refrigeration design team tion (RFI) or formal docu- and copies the refrigeration contractor. mentation requests For minor or verbal infor- The CxA goes directly to the informed party. mation and clarifications For notifying contractors The CxA documents deficiencies to associated of deficiencies contractor. Copies are sent to owner, refrigeration design team, and refrigeration contractor. For scheduling functional The CxA may provide input for and do some tests or training coordination of training and testing. For scheduling commissioning meetings

The CxA will try to schedule with construction meetings or will notify attendees directly.

For making a request for significant changes

The CxA can recommend changes to the owner but has no authority to issue change orders. The owner must approve significant changes.

For making small changes The CxA does not correct any deficiencies or in specified sequences of make any design engineering changes. The CxA operation may recommend sequence of operations (SoO) changes to improve efficiency or control but shall recommend the changes of specified sequences to the refrigeration design team and refrigeration contractor. Subcontractors disagree- Try and resolve with the CxA first. Then work ing with requests or inter- through refrigeration contractor, who will work pretations by the CxA with CxA directly to resolve the situation. ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

4. Schedule The schedule for this project will be as follows: Planning and Design Phase Event or Milestone

Time Frame

Commissioning Plan Owner’s Project Requirements Basis of Design Review Construction Document Review Review Training Requirements and Agenda Develop New Technical Procedures (if needed) Project Schedule Review and Update (if needed) Review of Deliverables and Turn Over to Next Phase Construction and Installation Phase Event or Milestone

Time Frame

Prebid Conference Preconstruction Meeting Develop Construction Checklist(s) Receive Contractor Submittals Contractor Submittals Review Schedule Review and Update (if needed) Site Visits Installation Technical Procedures Complete Construction Checklists Progress Report Final Installation Review and Turn Over to Next Phase Start-Up and First-Year Operation Phase Event or Milestone

Time Frame

Site Visits Training Sessions and Verification Start-Up and First-Year Technical Procedures Final Commissioning Process Report

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Appendix B ~ Example Commissioning Plan

5. Commissioning Du.ring the Planning and Design Phase a. Managing the Issues Log The issues log contains detailed descriptions of all issues encountered and resolved through all phases of commissioning. The CxA will maintain the log beginning at the outset of the project and track the issues through the end of the first year and will coordinate responsibility for resolving each issue. b. Developing the Owner’s Project Requirements (OPR) The OPR form the basis from which all design, construction, acceptance, and operational decisions are made. The CxA will facilitate the development of the OPR, but it is ultimately the responsibility of the owner to provide the necessary information. The owner will appoint one or more representatives who are responsible for core project parameters such as budget, schedule, and other project-specific restrictions and limitations and who can represent the owner’s technical goals and directives. Building operators (i.e., facility managers, store directors, and maintenance personnel) will also provide input to the OPR. c. Developing the Basis of Design (BoD) The BoD is developed by the refrigeration design team and records the concepts, calculations, decisions, and product selections used to meet the OPR and to satisfy applicable regulatory requirements, standards, and guidelines. As the BoD is being developed, the CxA will meet with the refrigeration design team to review the BoD and ensure that the OPR is being satisfied by the design. If any issues or concerns surface as the design is being developed, the CxA will bring them to the owner as soon as possible to achieve resolution. d. Developing the Construction Documents (CDs) The CDs provide the finer details for the design that was discussed in the BoD and must contain enough information so that the CxA can verify that the requirements in the OPR can be met. The designer responsible for producing the CDs must become familiar with the Commissioning Plan so that the design can adequately support the commissioning activities that will occur during construction and start-up. The CxA will facilitate review of the CDs. e. Reviewing Training Requirements The CxA will facilitate the owner’s definition of training requirements and expectations by ensuring lines of communication with all parties (including suppliers and contractors and those who will provide training information) as well as by obtaining input from those who will be responsible for using the training materials. f. Identifying Technical Procedures to be Conducted and Developing New Procedures The CxA will consult with the owner, refrigeration design team, and contractor to identify the technical procedures that will be conducted over the course of commissioning. In addition, the CxA will ensure that all necessary information for conducting the technical procedures is included in the documentation, namely the OPR, BoD, and CDs. If ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

there are any tests that the owner wishes to run for which a technical procedure does not yet exist, the CxA will facilitate the development of a new technical procedure and include it in the commissioning documentation. g. Turn Over to Next Phase At the end of the Planning and Design Phase, the CxA will provide the owner with all deliverables developed during this phase and ensure the owner has reviewed and accepted them. The CxA will also ensure that all parties involved in the Construction and Installation Phase, including the Engineer of Record and contractors, are aware of all commissioning documents and requirements and particularly any issues from the issues log that remain unresolved at the beginning of the next phase. The CxA will coordinate any feedback from parties involved in the next phase. 6. Commissioning During the Construction and Installation Phase a. Prebid Conference The CxA will attend the prebid conference or site meeting between the owner’s representative(s), Engineer(s) of Record, local authorities, general contractor, and various specialty trade contractors as required. During the meeting, the CxA should ensure that prospective refrigeration installation contractors are clear as to what the scope of the project includes and what aspects of the project will affect commissioning of the system. The CxA must also verify that the refrigeration installation contractor has the proper qualifications to execute the project per the project documents, using the BoD as a point of reference. b. Addressing Disputes and Changes The CxA will facilitate direct meetings between the owner and contractor(s) to clarify and agree upon any and all exceptions made to job specifications and plans by the contractor(s), any optional proposed supplements to the job specifications, and any other discrepancies between the job specifications and the proposal by the contractor(s). A written document finalizing the scope of work should be provided to the contractor from the owner or owner’s representative, and a written proposal including total cost to the owner should be submitted by the contractor. This should reference the current project documents and specifications, including any addenda. A line of communication should be established between all parties to handle items in dispute from the time the contract is signed until the work is complete and the refrigeration system is turned over to the owner. c. Equipment Procurement The CxA will ensure that the owner’s equipment specifications match project documents and that equipment submittals reflect the intent of the project documents. The CxA will document that the owner or owner’s representative and the suppliers have conducted a review of these documents and have verified that commissioning can be executed to expectations. The CxA will ensure that all reviews have considered the BoD. The CxA will also help the owner include commissioning aspects in purchasing requests for proposals (RFPs) for each major

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Appendix B ~ Example Commissioning Plan

equipment vendor where commissioning applies and will be involved in discussions with vendors to ensure they understand the requirements. d. Construction Scheduling The CxA will verify that the necessary time required to execute each step of the commissioning process during installation is built into the schedule and will confirm this with the owner and the refrigeration contractor. The CxA will ensure that certain steps requiring minimum time requirements or performance approvals are allowed sufficient time in the schedule. e. Reviewing Contractor Submittals The CxA will jointly review all contractor submittals with the responsible design engineers to ensure they conform to the commissioning and system performance expectations contained in the BoD and CDs. f. Conducting Technical Procedures The CxA will ensure that all technical procedures identified in the Planning and Design Phase that relate to the Construction and Installation Phase are conducted at the appropriate time and that results are documented. g. Completing Construction Checklists As tasks on construction checklists are performed, the entity responsible shall document that a task has occurred and the CxA shall record this documentation. Before start-up can begin, the CxA must verify that all checklist items have been completed. h. Progress Reporting The CxA will complete weekly progress reports during construction, which will include a description of commissioning activities taking place during that week, any new or outstanding deficiencies, and updates to the schedule. The CxA will communicate these reports to all members of the project team, particularly the owner, refrigeration design team, and refrigeration contractor. i. Final Installation Review After construction is complete and the refrigeration system is ready to run, the CxA will review with the owner all aspects of commissioning that have been associated with the project to date. The CxA will review the issues log and provide final feedback to the refrigeration design team, the owner, equipment suppliers, and/or others involved in the project on any items that deviated from the project plans that have not already been resolved. The owner must approve any deviations from the project plan before start-up can occur. The CxA shall ensure that any necessary updates are made to the commissioning documentation. j. Turn Over to Next Phase At the end of the Construction and Installation Phase, the CxA will ensure that all parties involved in the Start-Up and First-Year Operation Phase, including system operators, are aware of all commissioning documents and requirements, and particularly any issues from the issues ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

log that are unresolved at the beginning of the next phase. The CxA will coordinate any feedback from parties involved in the next phase. 7. Commissioning During the Start-Up and First-Year Operation Phase a. Verifying Training of Personnel The CxA will ensure that system operators have been trained according to the training requirements and expectations defined in the Planning and Design Phase. The CxA will obtain input from those who are responsible for using the training materials. b. Conducting Technical Procedures The CxA will ensure that start-up-related technical procedures identified in the Planning and Design Phase are conducted during the StartUp and First-Year Operation Phase. The intent is to verify that the refrigeration system and cases/coolers are operating as intended based on the OPR and BoD. The CxA will document the results of each procedure and note any issues in the issues log. c. Addressing Discrepancies The CxA will inform the owner of any discrepancies between expected and actual performance, will record the details in the issues log, and will work with the owner to decide upon appropriate corrective actions, accounting for factors such as impact on energy use and refrigeration system operation, the anticipated cost and schedule impacts, and the owner’s preferences. If the discrepancy could pose a risk to personal or equipment safety or impact the ability of the CxA to perform subsequent commissioning activities, the CxA should not proceed until the discrepancy is corrected. The CxA will document the outcome of each issue in the issues log. The CxA will assist the owner in resolving any warranty disputes (for example, by providing documentation). d. Final Commissioning Report After the end of the first year, the CxA will provide the owner with a final report detailing, for each component of the commissioned system, the outcome of any additional technical procedures relevant to that component performed during the first year of operation and any discrepancies between equipment design and as-built equipment. The CxA will also provide recommendations for improvement of the system or the commissioning process.

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Appendix C Example Acceptance Plan

This appendix provides an example acceptance plan. The acceptance plan details the key commissioning process activities that must be accomplished at the end of each phase in a project in order to move to the next phase. Planning and Design Phase Item

Initials

Date Completed

Owner’s Project Requirements (OPR) Owner provides OPR to refrigeration design team and commissioning authority (CxA) Refrigeration design team provides comments CxA provides comments Owner reviews the modified documents and makes any changes CxA reviews final version Refrigeration design team indicates that their design will reflect the final version of the OPR Commissioning Plan CxA provides Commissioning Plan to owner Owner provides comments CxA makes changes to Commissioning Plan Owner accepts final version Basis of Design (BoD) Refrigeration design team provides BoD to CxA and owner CxA provides comments Owner provides comments Refrigeration design team makes changes to BoD CxA reviews final version Owner accepts final version

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Item

Initials

Date Completed

Construction Documents (CDs) Refrigeration Design Team provides CDs to CxA and owner CxA provides comments Owner provides comments Refrigeration design team makes changes to CDs CxA reviews] final version Owner accepts final version Technical Procedures CxA confirms list of technical procedures that will be conducted during commissioning CxA confirms that all necessary information for completing technical procedures is included in the OPR, BoD, and CDs New technical procedures developed?

Y / N

If “Yes,” CxA reviews new procedures If “Yes,” owner accepts new technical procedures Phase Turnover CxA provides Planning and Design Phase commissioning deliverables to installation contractors and others involved in Construction and Installation Phase Parties involved in Construction and Installation Phase accept deliverables and responsibility for commissioning tasks Construction and Installation Phase Item

Initials

Date Completed

Submittals Contractors provide submittals to CxA, owner or owner’s representative, and Engineer of Record Owner or owner’s representative reviews submittals CxA reviews submittals Engineer of Record reviews and approves submittals Project Review Checklists CxA verifies that all project review checklist items are complete Documentation Updates Owner accepts revised OPR Owner accepts revised Commissioning Plan Owner accepts revised BoD Owner accepts revised CDs

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Appendix C ~ Example Acceptance Plan Template

Item

Initials

Date Completed

Pre-Start-Up and System Quality Control (QC) Contractors confirm refrigeration system ready to start Contractors confirm facility HVAC is running and ambient conditions are satisfactory Contractors confirm control valves are powered and cases are ready to receive cooling Technical Procedures CxA confirms that all installation-related technical procedures or sections thereof have been completed and the results have been documented New technical procedures developed?

Y / N

If “Yes,” CxA reviews new procedures If “Yes,” owner accepts new technical procedures CxA verifies that any discrepancies have been resolved or adequately documented Owner accepts results of technical procedures performed during this phase, including resolution of discrepancies Final Installation Commissioning, Review, and Turnover CxA performs final installation review CxA confirms documentation of installation steps Owner accepts any updates to commissioning documentation CxA provides documentation to personnel involved in start-up (e.g., system operators) Start-up personnel accept deliverables and responsibility for commissioning tasks Start-Up and First-Year Operation Phase Item

Initials

Date Completed

Documentation Updates Owner accepts revised OPR Owner accepts revised Commissioning Plan Technical Procedures CxA confirms that all start-up-related technical procedures or sections thereof have been completed and the results have been documented CxA confirms that all first-year technical procedures or sections thereof have been completed and the results documented New technical procedures developed?

Y / N

If “Yes,” CxA reviews new procedures If “Yes,” owner accepts new technical procedures CxA verifies that any operational discrepancies have been resolved or adequately documented Owner accepts results of technical procedures performed during this phase, including resolution of discrepancies

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Item

Initials

Date Completed

Handoff to Owner CxA verifies that operators have received required training Owner accepts handoff of commissioned system Resolution of Warranty Issues CxA provides memo to owner that warranty issues have been addressed before expiration of warranty (or verifies that there are no issues) Owner accepts memo on warranty issues Final Commissioning Process Report CxA provides final commissioning process report to owner Owner accepts final commissioning process report

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Appendix D Technical Procedures

The technical procedures in this appendix were originally prepared for the Better Buildings Alliance in the Building Technologies Office of the Office of Energy Efficiency and Renewable Energy of the U.S. Department of Energy (DOE). That information was developed with the assistance of Navigant Consulting, Inc. in cooperation with the Refrigeration Commissioning Guide Project Committee. During the development of this Guide, these procedures were modified and refined to the version presented here. These technical procedures are jointly published by DOE and the Better Buildings Alliance and will be freely available at www4.eere.energy.gov/alliance. These technical procedures describe certain functions or activities that may be conducted in terms of performance and energy efficiency when commissioning refrigeration systems. The steps in each procedure are intended to provide sufficient guidance to someone with the necessary skills and training to perform the procedure while allowing flexibility, as there is generally more than one way to execute each procedure. The activities listed under each procedure are organized by commissioning phase (Planning and Design, Construction and Installation, and Start-Up and First-Year Operation). The procedures are not exhaustive but are examples that represent some common commissioning activities. They are modular and may be used together or singly; the Commissioning Plan should specify which technical procedures are to be performed as part of commissioning. The commissioning team may amend these technical procedures and develop additional procedures as necessary to suit the equipment, systems, controls, and commissioning expectations for a given project.

1

VERIFYING CONTROL FUNCTIONS Introduction

Control systems can optimize refrigeration system efficiency and improve reliability while minimizing maintenance requirements. Control system functions may include, but are not limited to, the following: • Equipment failure detection and diagnostics (FDD)

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

• Communicating with and/or controlling lighting and HVAC systems • Communicating with embedded controls • Facilitating remote monitoring and control through the energy management system (EMS) and energy information system (EIS) or other means • Integrating control signal access to HVAC and refrigeration systems Successful operation of refrigeration control systems requires more than proper design and installation of the associated hardware and software. It also requires training to ensure that operators and others monitoring the system know how to use the system, how to interpret and act upon system outputs, and how to restore full functionality if a control function must be temporarily adjusted or bypassed.

Definitions Planning and Design Phase

As used here, the EMS includes, but is not limited to, remote monitoring functions. Ensure that the Owner’s Project Requirements (OPR) specify the following: • Top-level functional descriptions for the refrigeration control system, including the following: • Desired capabilities for FDD • Characteristics of user interfaces (on site and remote) • Specific requirements for all interfaces with equipment not included in the project (such as existing equipment, lighting systems, HVAC systems, and security systems) • Interoperability requirements (open native, open nonnative, proprietary), if any • Functional performance tests (FPTs) required (can be a subset of the procedures listed in Technical Procedure 4, Checking Refrigerant Temperatures and Pressures and Evaluating Setpoints, and Technical Procedure 5, Verifying Operation of Alarms) • Security features desired Ensure that the Basis of Design (BoD) or sequence of operations (SoO), as appropriate, includes: • Detailed control sequences and the process by which they were reviewed/checked • Hardware and software required, including interfaces with embedded controls (as required) and with the EMS (if present) • Type and installation location of user interfaces • Monitoring and recording capabilities • Security features provided • Type, location, and installation method for all sensors included in the refrigeration control system • Operator training requirements to help ensure proper use and maintenance of control systems. Ensure that the design documents clearly show who supplies and how and where to install all sensors, interconnecting wiring, user interfaces, interfaces

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Appendix D ~ Technical Procedures

with embedded controllers, interfaces with equipment not included in the project, and other hardware associated with the refrigeration control system. Verify that the Commissioning Plan includes any changes or additions required to the procedures outlined below for the Construction and Installation Phase and Start-Up and First-Year Operation Phase or a statement indicating that no changes or additions are needed.

Construction and Installation Phase

Verify that the following components of the control system are installed according to the design documents: • User interfaces • Sensors (to the extent that they are accessible) • Interfaces with embedded controls • Interfaces with EMS and EIS (if present) Verify other components as specified in the Commissioning Plan. After the control system has been installed but before refrigeration system start-up, verify the following: • User interfaces are functional • Initial setpoints and operating schedules (as appropriate) have been programmed • EMS and EIS (if present) are communicating properly with the refrigeration control system • Operators have received the training as indicated in the BoD

System Start-Up

Verify operation of each control function as outlined below: • FDD • Where practical and where it can be accomplished without risking injury or damage to equipment, simulate “failures” and verify that the control system reports the “failure” as intended. • Interfaces with HVAC and lighting systems • Verify that the HVAC and lighting systems respond appropriately when scheduling signals are sent. • If communications with HVAC and lighting systems go beyond scheduling functions, inspect available data for evidence that these other functions are being performed as intended, following the procedures outlined in the Commissioning Plan. • Facilitating remote monitoring and control • Verify that individual having remote access can monitor data. • Verify that individual having remote access can execute a sample of the remote-control features that the design specifies (if any). This may include adjusting temperature setpoints, changing schedules, or similar control features. • Other control functions • Verify as specified in the Commissioning Plan.

First-Year Operation

Interview on-site operators and maintenance personnel to verify the following: • Control and monitoring functions are working as designed. • Operators and other users are using control and monitoring functions consistent with their design intent. Document any issues identified, including any supplemental training needed.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

• No control functions have been bypassed. Document explanation for any bypassed control function reported. • Operators have received the training as indicated in the BoD. Inspect the control system for evidence that any control functions have been bypassed (in addition to any evidence identified through interviews with operators and maintenance personnel). Verify operation of each advanced control function as outlined below: • FDD • Review maintenance history during first year of operation to verify that the advanced control system detected the failures that it was designed to detect. • Interfaces with HVAC and lighting systems • If available, review utility interval data for evidence that the intended HVAC and lighting schedules are being followed. • If communications with HVAC and lighting systems go beyond scheduling functions, inspect available data for evidence that these other functions are being performed as intended, following the procedures outlined in the Commissioning Plan. • Facilitating remote monitoring and control • Interview remote operators to verify the following: • Control and monitoring functions are working to the satisfaction of the operator. • Operators are using control and monitoring functions consistent with their design intent. • Document any issues identified, including any supplemental training needed. • Other control functions • Verify as specified in the Commissioning Plan.

2

VERIFYING REFRIGERATION SYSTEM CAPACITY

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Introduction

Commercial refrigeration systems are designed to have sufficient refrigerating capacity to accommodate the design load (typically the highest load that the system is expected to encounter), accounting for losses in interconnecting piping. Further systems are designed to meet the design load at the design ambient dry-bulb or wet-bulb temperature (typically, an ambient temperature at or near the highest temperature experienced in the region). This procedure verifies that a system has the capacity to meet the design load at the extreme conditions at which it was designed to operate.

Planning and Design Phase

Ensure that the OPR specifies the following: • Specifications for individual and total compressor capacity (CC) to be supplied by the compressor rack manufacturer • Data collection frequency and method, including a description of any software used to record and analyze data

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Appendix D ~ Technical Procedures

• Method by which the system’s capacity will be adjusted to account for the difference between actual ambient conditions and design ambient conditions At the owner’s option, the OPR may specify use of one of two methods for verifying system capacity (see the primary and alternative methods discussed in the First-Year Operation section). The owner may want to use the alternative method if the primary method does not verify capacity to the owner’s satisfaction. Ensure that the BoD specifies all design conditions, including the following: • Design capacity, including safety factor • Design ambient dry-bulb and/or wet-bulb temperature • Design saturated condensing temperature (SCT) • Design saturated suction temperature (SST) For retrofits, if the system is being redesigned such that loads are being changed (for example, replacing open cases, retrofitting existing cases with doors, or adding new cases), the designer must verify that the system design capacity is sufficient to meet the design load if the load is increasing or to operate and stage correctly if the load is being reduced. In the situation where the load is decreasing by a significant percentage of the original capacity, special attention needs to be given to oil management and compressor staging to ensure system performance and longevity.

Construction and Installation Phase

During the Construction and Installation Phase, verify that sensors and other instrumentation are installed and configured according to the plans, specifications, submittals, and other construction documents (CDs). If changes are made in the as-built design, record and document those changes quantitatively for use in later assessment of the installed system.

System Start-Up

To reduce commissioning burden, commissioning activities at start-up provide only a rough check of system capacity. With all cases and coolers operating at their design setpoint temperatures, loaded with product, and with proper interior space conditions, check the fraction of total CC in operation. Based on the actual ambient air temperature, determine whether the fraction of CC operating is consistent with expectations. If more of the available CC is in use than expected, and at the owner’s option, follow the alternative method discussed in the First-Year Operation section to verify system capacity.

First-Year Operation

During the first year of operation, record and archive the system’s operating profile, recording data as specified in the OPR, including the following: • Settings of adjustable components such as expansion valves (for example, expansion valve superheats may be spot checked or return gas temperatures [RGTs] may be reviewed) • Compressor conditions • Suction and discharge pressures • Discharge temperature • RGT • Compressor and unloader cycle times and operating profiles (on/off status at each time step—typically 1 min time steps)

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

• Compressor speed • Percent on-time (for pulse-width modulation compressors) • Condenser conditions • Speeds and operating profiles for each condenser fan (on/off status at each time step—typically 1 min time steps) • Wet- and dry-bulb temperatures of the ambient air • Refrigerant temperature and pressure entering the condenser • Drop-leg temperature and pressure • Entering water temperature (EWT) and leaving water temperature (LWT) (for water or evaporatively cooled condensers) • System conditions • Suction header temperature • Subcooled liquid temperature • Liquid header pressure • Case and cooler temperatures • Temperature range during refrigeration • Temperature range during defrost

Primary Method to Verify Capacity

At the earliest appropriate point during the first year, identify a time period (minimum of 4 h) during which the system operated at conditions close to the design conditions—most importantly, near or at the design ambient drybulb and/or wet-bulb temperature. Verify that case and cooler temperatures remained at or below setpoints. Estimate the CC from the compressor conditions over the time period for time intervals of 15 min or shorter. During intervals when all compressors are operating at full capacity, verify that the CC matched or exceeded the design capacity. Figures D-1 and D-2 illustrate such a comparison. If there is no time interval during which all compressors were operating at full capacity, make this comparison by estimating the maximum CC: Estimated Maximum Compressor Capacity = Actual Compressor Capacity  Fraction of Compressor Capacity in Operation

Alternative Method to Verify Capacity

At the owner’s option, if the primary method listed above does not provide adequate verification of capacity, perform a test of the system as outlined below: • Operate all cases and coolers at their design setpoint temperatures. • Disable defrosts. • If possible, raise the store temperature to 75°F (24°C). • Adjust the condenser setpoint so that the condensing temperature is approximately the condensing temperature expected at the design ambient air temperature when operating at the design capacity. • Record data as outlined for the primary method above for a time period of at least 4 h. Verify that case and cooler temperatures remained at or below setpoints. Estimate the CC from the compressor conditions over the time period for time intervals of 15 min or shorter. During intervals when all compressors are operating at full capacity, verify that the CC matched or exceeded the design

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Appendix D ~ Technical Procedures

Figure D-1 Example Graph of Actual vs. Design Capacity

Figure D-2 Example Graph of Temperature Profiles

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

capacity. If there is no time interval during which all compressors were operating at full capacity, make this comparison by estimating the maximum CC: Estimated Maximum Compressor Capacity = Actual Compressor Capacity  Fraction of Compressor Capacity in Operation Because the alternative method causes the condenser to operate under conditions that depart from normal operation, the condenser performance must be independently verified. From the recorded system operational data, identify a time period (minimum of 4 h) during which the system operated at conditions close to the design conditions—most importantly, near or at the design ambient air temperature and when all condenser fans were operating. Calculate the condenser approach temperatures over this time period for time intervals of 15 min or shorter. Compare actual approach temperatures to the design temperature approach. If the actual temperature approaches exceed the design approach by more than 20%, the condenser may not be performing per the design intent.

3

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EVALUATING PART-LOAD OPERATION Introduction

Commercial refrigeration systems are designed to operate over the range of loads and conditions to which they may be subjected throughout the course of intended use. Load variation can be due to changes in indoor-air conditions, shopper traffic, product loading, and the temperature settings of the display cases and coolers. The combined effects of these factors can lead to fluctuation in the loads placed on the refrigeration system over the course of any given day, week, month, or year. Similarly, the capacity of the system is affected by outdoor-air conditions—primarily outdoor dry-bulb temperature. While the refrigeration system is generally sized to accommodate the highest anticipated load, measures are also taken during design and construction to match system capacity to part load, as this is the regime in which the system operates most of the time. Ensuring that the system is delivering the desired capacities under a range of load conditions is vital to protecting inventory, ensuring safe operating temperatures and pressures, and maximizing energy efficiency.

Planning and Design Phase

Ensure that the OPR specifies the following: • Whether part-load analysis should be undertaken; in other words, whether expected system capacity at various load steps needs to be verified and compared with operating capacity for conditions other than design conditions • Data collection frequency and method, including a description of any software used to record and analyze data Ensure that the BoD specifies the following: • Operating loads for individual pieces of equipment attached to the system, such as display cases and walk-ins, based on the list and description of required refrigeration equipment in the OPR

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Appendix D ~ Technical Procedures

• Maximum total anticipated field load, minimum load expressed as a percentage of the maximum load, and any intermediate operating loads • At each capacity step: • Maximum percent increase (from minimum capacity) or decrease (from maximum capacity) represented by capacity step • Which compressors are in operation, itemizing each compressor’s contribution to the capacity • Maximum compressor cycle rate • Maximum difference between design and actual suction pressures Ensure that the design documents include the following: • Percent of total capacity allotted to each refrigerant circuit and percent of capacity in a circuit allotted to each load on the circuit (display case, walk-in, etc.) For retrofits, if the system is being redesigned such that loads are changing (for example, adding doors to cases, replacing existing cases with higherefficiency cases, or adding new cases or coolers), the designer must verify that the original capacity steps are still applicable. If they are not, the designer must modify the equipment to provide sufficient capacity modulation.

Construction and Installation Phase

During the Construction and Installation Phase, verify that sensors and other instrumentation are installed and configured according to the design plans. If changes are made in the as-built design, record and document those changes quantitatively for use in later assessment of the installed system.

System Start-Up

Verify that the system uses the designed capacity steps to satisfy the current suction-pressure setpoint. Operate the system for 24 h, recording the following: • Settings of adjustable components such as expansion valves • Compressor conditions • Suction and discharge header pressures • Discharge header temperature • Compressor and unloader cycle times and operating profiles (on/off status at each time step—typically 1 min time steps) • Compressor speed • For pulse-width modulation compressors, percent on-time • Case and cooler temperatures Estimate CC over the analysis period from the suction and discharge conditions and compressor and unloader cycle times and operation profiles. Do this for time intervals of 15 min or less. At each capacity step experienced during the analysis period, verify that the highest observed rate of compressor cycling and the lowest suction pressure are consistent with the specifications in the BoD. Also review data to ensure that there was no liquid floodback to the compressors by comparing SST to actual suction gas temperature.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

First-Year Operation

During the first year of operation, document the system’s operating profile, collecting data as specified in the OPR. Record the following: • Settings of adjustable components such as expansion valves • Compressor conditions • Suction and discharge pressures • Discharge temperature • Compressor and unloader cycle times and operating profiles (on/off status at each time step—typically 1 min time steps) • Compressor speed • For pulse-width modulation compressors, percent on-time • Case and cooler temperatures During the first year of operation, review the system’s performance at least once per season (winter, summer, and swing seasons): • Select a recent 24-hour operating period. • Estimate CC over the analysis period from the suction and discharge conditions and compressor and unloader cycle times and operation profiles. Do this for time intervals of 15 min or less. • At each capacity step experienced during the analysis period, verify that the highest observed rate of compressor cycling and the lowest suction pressure are consistent with the specifications in the BoD.

4

CHECKING REFRIGERANT TEMPERATURES AND PRESSURES AND EVALUATING SETPOINTS Introduction

This technical procedure verifies system setpoints for refrigerant temperatures and pressures. The procedure verifies that temperature and pressure sensors are reading correctly and providing the proper input to the controller. It also checks the condenser and evaporator setpoints and pressure and temperature conditions to ensure that they are consistent with the design intent and with appropriate approach temperatures, superheats, and subcooling.

Planning and Design Phase

Ensure that the OPR specifies the following: • Which sensors and setpoints are most critical to system operation and performance and the required frequency and sampling rate at which these sensors and setpoints must be verified in operation Ensure that the BoD specifies the following: • Whether floating high-side (head) pressure and/or floating low-side (suction) pressure control strategies are to be used • Condenser type (air cooled, evaporatively cooled, or water cooled with a cooling tower) and control strategy for each type of condenser • Maximum pressure drop in the suction line • Type of electronic controls, what is being controlled, and what strategy is to be used for each type of component controlled

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Appendix D ~ Technical Procedures

• Type of expansion valves to be used (typically thermostatic expansion valve [TXV] or electronic expansion valve [EEV]) • Type, location, and installation details for all refrigerant temperature and pressure sensors required for control, commissioning, or diagnostics, including those for purchased components such as cases • Design evaluation or justification for selection of piping system (loop piping vs. standard) • Control sequence for floating high-side pressure and floating lowside pressure, if these systems are to be used • Lower limits to allowable condensing temperature to maintain adequate pressure differential for safe compressor operation and proper operation of expansion valves Ensure that the design documents specify the following: • For all operable devices, the default operating condition or the programmed setpoint. • For controlled devices, associated setpoint or specification that setpoints must be consistent with case manufacturers’ recommendations. Describe inputs and outputs of each setpoint and whether each setpoint is writable, readable, or rewritable at the controller. Typical setpoints include the following: • Case and walk-in discharge air temperatures (DATs) • Defrost setpoints • Evaporator superheat temperatures and pressures

Construction and Installation Phase

As each sensor is installed, verify that it is correctly wired to the control system.

System Start-Up

Verify that all pressure, temperature, and electronic-valve sensors— including all rack-control sensors and case-control sensors—are reading correctly and the controller is getting input from the sensors: • Verify connections between sensors and controller by turning off or disconnecting each sensor individually and checking that the sensor input is recorded as “off” or “open” at the controller. • Verify sensor outputs by using independent sensors that have a greater precision than the system sensors. Independent sensors must be calibrated using the method specified in section NA7.10 of Reference Appendices for the 2008 Building Energy Efficiency Standards for Residential and Nonresidential Buildings (CEC 2008). • If there is a readable gauge, verify the reading on the gauge with an independent calibrated gauge. • For case air temperatures, measure the temperature of the discharge air at the honeycomb; for walk-in air temperatures, measure the temperature of the return air. Analyze the data from the sample of sensors tested. If problems are discovered with the sensors, controller, or connection between the two, take corrective action with the system designer or equipment vendor, as appropriate, before proceeding. Once validity of controller readings have been established, verify condenser and suction setpoints and conditions.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Verify condenser conditions as follows: • Verify that the condenser is operating within the allowable range of subcooling specified in the BoD. • Verify that condenser fans are staging, or that fan speed is modulating, to maintain the setpoint temperature difference (TD). • For systems having floating high-side pressure, verify that the condensing temperature exceeds the outdoor air temperature by about the target approach temperature specified in the control sequence. If the condensing pressure is at or near the minimum allowable pressure, the actual approach temperature may exceed the target approach temperature, and this test is not necessary. If the ambient temperature is below the design minimum, perform this test again during the first year to verify operation of floating high-side pressure. • For systems having mechanical condenser holdback valves, verify that the pressure setting for the holdback valve is lower than the minimum operating condensing pressure specified in the OPR. • For systems having flow-through (bypass) receivers, verify that the flow-through control valves are adjusted per the requirements of the OPR and/or rack manufacturer specifications. • Verify that the system has been tested to ensure that it is free of noncondensable gases. Verify suction conditions as follows: • Verify that the pressure drop—i.e., the difference between the suction pressure (measured at the compressor rack) and the refrigerant pressure at the outlet of the evaporator operating at the lowest setpoint temperature in the circuit—is less than or equal to the design pressure drop. • Verify that the return gas temperature (RGT) is less than 40 degrees above the suction temperature and within the compressor manufacturer’s operating envelope. • If the system has a floating suction pressure control strategy, verify that the maximum and minimum suction pressures have been programmed and that the minimum suction pressure float target is no lower than that required to satisfy the operation requirement of the evaporators and associated parasitic losses. • Verify evaporator superheat, prioritizing the evaporator(s) operating at the lowest setpoint temperature: • If the system has a floating suction pressure control strategy, then suction pressure should be stabilized at the high-float limit. • If the system has a fixed suction pressure control strategy, then suction pressure should be stabilized at or slightly above the design suction pressure setpoint. • Check liquid conditions: • No flash gas is present at the inlet to the valve (thermostatic expansion valve [TXV] or electronic expansion valve [EEV]).

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Appendix D ~ Technical Procedures

• Subcooled liquid temperature is stable and at the design temperature. • Liquid pressure at the liquid header is at or above the minimum design setpoint. • Determine the proper superheat from the manufacturer’s literature, the OPR, or the CDs. • Measure pressure at the evaporator suction pressure port and measure temperature at the expansion valve bulb location with a temperature probe. • Determine the saturated vapor temperature of the refrigerant based on the pressure measured at the outlet of the evaporator. Calculate superheat as the difference between the actual outlet temperature and the saturated vapor temperature. For zeotropic refrigerants having significant temperature glide, use the dew-point temperatures when calculating superheat. If adjustment of the valve is necessary, or if superheats meet design conditions but there is a large pressure drop between the evaporator outlet and the compressor rack, notify the owner, operator, or system designer so that corrective action may be taken.

First-Year Operation

5

Throughout the first year, verify the critical sensors and setpoints as specified in the OPR. If the OPR does not specify critical sensors and setpoints, check pressure transducers and temperature and humidity sensors at least once per season and verify that their setpoints are appropriate if applicable. For systems having floating high-side pressure, during a variety of weather conditions, or at least once per quarter, verify that the condensing temperature exceeds the outdoor air temperature by at least the target approach temperature specified in the control sequence. At the end of the first year, do the following: • Obtain historical data from the controller and review system operation history with the operations/maintenance department. • Report deficiencies to the building owner and refrigeration engineer so that corrective action may be taken.

VERIFYING OPERATION OF ALARMS Introduction

Refrigeration systems often incorporate alarms that help protect inventory and equipment by alerting operators of elevated storage temperatures or conditions that could damage the refrigeration system or otherwise compromise its ability to adequately cool cases and walk-in coolers. Alarms may be on individual pieces of equipment, in a central system location such as the mechanical room, or at a remote monitoring site. This procedure details steps for testing and verifying operation of commonly used alarms and notifications.

Planning and Design Phase

Ensure that the OPR specifies the following: • Alarms or specific alarm functions that must be included in the system.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

• The most critical alarms from a safety or system performance standpoint. If desired, list alarms that must be tested during the Start-Up and First-Year Operation Phase. • Requirements for remote alarm monitoring. • System for analyzing alarm records to identify trends that would indicate a need for further investigation, maintenance, and/or repair. Include a description of any software to be used to conduct analysis. Ensure that the BoD specifies the following: • For each alarm sensor installed: type of sensor input, setpoint that triggers an alarm, duration that the alarm setpoint must be triggered, location of sensor, and installation method • Any required interfaces between alarms and EMS or EIS • Type and location of each alarm output device, e.g., a buzzer, light, dial-out (call), other notification, email to an email address, etc. Ensure that the design documents specify the following: • System design features to accommodate sensor mounting Ensure that the Commissioning Plan is updated, as necessary, to include the following: • Commissioning process for system-specific alarms that are not covered in this technical procedure

Construction and Installation Phase

Verify that sensors and alarm outputs are located and wired as specified in the OPR, BoD, and CDs.

System Start-Up

During the Start-Up and First-Year Operation Phase, verify operation of alarms as specified in the OPR and Commissioning Plan. The following examples describe how to verify the operation of the alarms that are likely to be most important from a safety or operation standpoint. The functional tests that follow were adapted from the working draft of the 2011 update to NA7; therefore, the final published tests may vary from the information presented here.

Case and Walk-in Temperature Alarms

Checking operation from the control system • Determine the location of the case or walk-in temperature sensor from the BoD. Using an independent temperature sensor, confirm the case or walk-in thermostat reading. • Verify that the temperature alarm setpoint is set to the temperature specified in the BoD. • Using the control system, lower the temperature alarm setpoint to a point at or just below the case or walk-in temperature. Verify that there is an alarm output and that it is consistent with the OPR. Alarm delays may be shortened to accelerate verification as long as they are reset to the proper delays after verification. • Return temperature alarm setpoint to its correct setting. Alternative method: Checking operation at the case • Determine the location of the case or walk-in thermostat or temperature sensor from the BoD. Using an independent temperature sensor, confirm the case or walk-in thermostat reading.

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Appendix D ~ Technical Procedures

• Safely apply a low-grade heat to the alarm sensor until the alarm is triggered. If possible, verify that the temperature measured by the sensor is the same as the alarm setpoint in the BoD. Verify that the alarm output is consistent with the OPR.

Walk-In Box Door Open Alarms

Using a stopwatch, determine the time between when each door is opened and when an alarm or performance notification is triggered. Compare this time to the design in the BoD.

Refrigerant Temperature and Pressure Alarms

Refrigerant head pressure too high • Determine the high head pressure setpoint from the OPR or BoD. • With the system running, determine the head pressure either from the control system or by measuring the pressure directly if there is a pressure port. If possible, disable floating head pressure controls to maintain the head pressure at a fixed point for purposes of alarm testing. • At the control system, change the control setpoint, sensor reading, or alarm setpoint, as appropriate, to generate an alarm condition. Verify that this actually triggers an alarm and verify that the alarm output is consistent with the requirements specified in the OPR and BoD. Refrigerant suction pressure too low • Determine the low suction pressure setpoint from the OPR or BoD. • With the system running, determine the suction pressure either from the control system or by measuring the pressure directly. If possible, disable floating suction pressure controls to maintain the suction pressure at a fixed point. • At the control system, change the low suction pressure setpoint to the current suction pressure. Verify that this triggers an alarm and verify that the alarm output is consistent with that specified in the OPR and BoD.

Refrigerant Leakage Alarms

Determine from the BoD all locations for refrigerant leak sensors and events that should trigger an alarm (EPA 2011a). If there is an alarm for low refrigerant levels in the receiver: • Verify that the receiver liquid level probe has been calibrated. • With the system fully charged and the low refrigerant level setpoint at its design setting, verify that there is no alarm output (i.e., the system is not detecting a low charge). • At the control system, gradually raise the low refrigerant level setpoint until the alarm is triggered and verify that the alarm output is consistent with that specified in the OPR and BoD. • If the low refrigerant level setpoint cannot be changed, manually adjust the input signal for refrigerant level until it reaches the setpoint. Verify that an alarm is triggered and the alarm output is consistent with that specified in the OPR and BoD. For refrigerant detection alarms in mechanical rooms and walk-in coolers: • If the refrigerant detection alarm is connected to the central control system: at the central control or EMS, manually adjust the input signal for refrigerant concentration until it reaches the setpoint. Verify that an alarm is triggered, that any valves close that are required to

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

close, and that the alarm and control responses and the alarm outputs are consistent with the requirements specified in the OPR and BoD. • Calibrate refrigerant sensors to the proper refrigeration concentration (i.e., parts per million) according to code requirements and sensor manufacturer’s recommended methods.

Oil Level or Oil Pressure Alarms

Industry-recommended alarm checks (Maxson 1995) • For a low oil level alarm: at the control system or EMS, manually override the input signal for oil level to simulate a low oil level. Verify that this triggers an alarm and the alarm output is consistent with that specified in the OPR and BoD. • For a compressor oil pressure alarm: manually simulate a low oil pressure signal from the compressor, either by simulating a signal to the control system or by manually disconnecting the low oil pressure control and closing the circuit to simulate a loss of oil pressure. Verify that this triggers an alarm and the alarm output is consistent with that specified in the OPR and BoD.

Condenser Water Alarms (Water-Cooled or Evaporatively Cooled Condensers Only)

Sump temperature or fluid loop temperature alarms (if used) • Determine temperature setpoint from the control system. If possible, verify water temperature with an independent thermostat. Lower the temperature setpoint until it matches the water temperature. Verify that this triggers an alarm and the alarm output is consistent with that specified in the OPR and BoD.

First Year Phase

During the first year of operation: • Document all alarm events. • On a periodic basis, evaluate alarm records for trends using the system specified in the OPR. • Interview maintenance and operations personnel, if possible, to determine if there have been recurring alarms that could indicate a system problem.

6

EVALUATING REFRIGERANT PIPING Introduction

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This technical procedure applies to the testing and/or inspection of refrigerant interconnecting piping for facility refrigeration systems. Commercial refrigeration systems require field installation of refrigerant piping to connect major system components such as compressor racks, condensers, and display cases or walk-in coolers. Depending on the facility layout and type of refrigeration system, refrigerant piping runs can be many hundreds of feet (metres), requiring substantially higher refrigerant charge volumes (typically hundreds of pounds [kilograms]) and significantly more field joints compared to other vapor-compression equipment such as HVAC equipment or self-contained refrigeration equipment. This characteristic tends to increase both the probability of a refrigerant leak and the consequences associated with a refrigerant leak, including greater cost of repair and maintenance and greater environ-

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Appendix D ~ Technical Procedures

mental impacts. Furthermore, this characteristic also requires proper system design to ensure that compressor oil returns to the compressor sumps.

Definitions and Abbreviations

Secondary loop refrigeration system: Employing a heat-transfer fluid to cool display cases and coolers that is, in turn, cooled by a refrigerant evaporator. The heat-transfer fluid may be single phase (liquid at all points in the loop) or two phase (liquid that evaporates in a heat exchanger in the case or cooler but with minimal pressure drop, i.e., the liquid is not expanded to a two-phase mixture as in a direct expansion [DX] refrigeration system).

Planning and Design Phase

Ensure that the OPR specifies the following: • Facility layout, especially the locations of refrigerated display cases, walk-in coolers, and machine room • Inspection requirements, if any, for brazed joints of refrigerant piping Ensure that the BoD specifies the following: • The desired refrigeration system type (multiplex, distributed, secondary loop, or other) • Type of defrost system, consistent with refrigeration system type • Refrigerant type or types (if system uses a secondary loop) • Evaluation of design options to minimize refrigerant charge within the constraints specified in the OPR • Description of refrigerant system design that is consistent with the requirements of Section 4 of ANSI/ASHRAE Standard 147 (2013c); in case of conflict with the California Green Building Standards Code (CALGreen) (CA 2013a), ASHRAE Standard 147 supersedes Ensure that the CDs specify the following: • Evaluation of refrigerant pressure drops, showing that pressure drops will be in acceptable ranges • Piping layout (types, materials, sizes, support, slope, traps, risers, insulation, etc.) • Accessibility of refrigerant lines for measuring refrigerant temperatures and pressures to facilitate commissioning and troubleshooting. In particular, ensure that the following are specified: • Method of attachment and insulation of temperature sensors • Pressure gauge connection (e.g., angle valve) at the condenser • Receiver size, pumpdown capacity, orientation (vertical or horizontal), type (pumpdown or flow through), and trim • Heat reclaim piping, if heat reclaim is used • Estimated refrigerant charge • Estimated oil charge and composition • Piping insulation requirements • Refrigerant piping, valves, cases, and receivers that are consistent with the requirements in Section 5.508, Outdoor Air Quality, of CALGreen (CA 2013a), except that the requirements for compliance with the California Mechanical Code (CA 2013b) apply only for installations in California • Brazing materials, method of brazing, purge requirements, etc., including any industry brazing specifications that must be followed

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

(e.g., brazing guidelines from the Copper Development Association or ASTM International) • Provisions for managing noncondensables

Construction and Installation Phase

Verify that the following are installed as specified in the design documents: • Refrigerant piping, including type, size, layout/orientation, supports/ clamps/sleeves, valves and fittings, taps for instrumentation, receivers, mounting, and vibration isolators • Piping insulation • System for managing noncondensables Verify that the refrigerant system was installed per the requirements of Section 7.1 of ASHRAE Standard 147 (2013c). In case of conflict with CALGreen (CA 2013a), ASHRAE Standard 147 supersedes. Verify that joints have been brazed in accordance with any industry specifications listed in the design documents. Inspect brazed joints in refrigerant piping per the requirements of the OPR.

System Start-Up

Prior to pressure testing and evacuation, verify the following: • All refrigerant valves are open so that no part of the refrigeration system is isolated from the rest of the system • Pressure and vacuum gauges are connected to the appropriate ports on the refrigeration system (not at the vacuum pump) Verify by observation that the refrigeration system was pressure tested and evacuated per the requirements of Sections 5.508.2.5 and 5.508.2.6 of CALGreen (CA 2013a). Verify by observation that the refrigerant system was leak tested, evacuated, and charged per the requirements of Sections 7.2–7.5 of ASHRAE Standard 147 (2013c). In case of conflict with CALGreen, ASHRAE Standard 147 supersedes. After the system is charged with refrigerant and oil, verify that lubricant levels stabilize within 48 h of initiation of system operation. After all systems are on, refrigerated cases and walk-in boxes have been loaded, and heat reclaim and gas defrost are operational, do the following: • Compare actual refrigerant charge to that estimated and documented in the BoD and CDs. Provide a document comparison and report the results to the owner and designer. • Inspect all accessible refrigerant piping to ensure that there are no vibrations that could lead to premature piping failure, especially any that cause metal-to-metal rubbing.

First-Year Operation

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Whenever refrigerant or lubricant is added, verify that the date and quantity added are documented in a designated log, consistent with the requirements of Section 8.4.1 of ASHRAE Standard 147 (2013c). Plot trends over time and note any excessive refrigerant charge or lubricant loss. After one year, do the following: • Inspect piping runs for signs of corrosion, evidence of leakage (for example, traces of lubricant), and any other abnormalities. Document in a log the condition of piping and the location/details of any abnormalities.

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Appendix D ~ Technical Procedures

• Where refrigerant lines and components are accessible, use a portable refrigerant leak detector to check for leaks. If there is evidence of refrigerant leakage, notify the owner, designer, and/or operator so that they may take corrective actions per Section 8 of ASHRAE Standard 147 (2013c). • Remove a sample of the refrigeration oil and perform an analysis to ensure its composition is consistent with the design documents or manufacturer’s recommendations.

7

VERIFYING ANTI-SWEAT HEATER CONTROL OPERATION Introduction

Glass display doors on refrigerated cases, walk-in coolers and freezers, and some open-throat refrigerated cases are almost always equipped with antisweat heaters—that is, a wire around the door frame that uses electrical resistance heating to prevent condensation (liquid or frost) from forming on the glass. Case manufacturers or field installers may include anti-sweat heater controls that cycle the heaters on and off rather than operating heaters continuously. This technical procedure verifies that anti-sweat heater controls are operating adequately.

Planning and Design Phase

Ensure that the OPR specifies the following: • Manufacturers’ equipment or control specifications, if any, for refrigerated cases and/or walk-in coolers with glass display doors • If implemented, whether anti-sweat heater controls must be continuously monitored and/or alarms implemented (e.g., continuously monitor the amperage or the power, compare power consumption and/or runtime to the control strategy, and automatically notify operators when heaters are on for a long period of time) Ensure that the BoD specifies the following: • Anti-sweat heater control method (contactors, pulse-width modulation, etc.) • Anti-sweat heater control strategy, including the following: • All setpoints and the corresponding output of the control • Whether humidity or dew-point temperature is to be used as the control variable • An anti-sweat heater control strategy for pulse-width modulation—an example is as follows: Setpoint

Target

On Above

55°F (13°C) dew-point temperature

Cycle Above

20°F (–7°C) dew-point temperature

Cycle Time*

5s

* The percentage of the cycle time that the heaters are on is typically linearly proportional to the measured dew-point temperature in relation to the two setpoints.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

• For sensors: type, location, installation method, and whether they are monitored for failure Ensure that the CDs specify the following: • Circuit details • Whether the control uses a solid-state relay or a contactor • What circuits incorporate heaters • What breaker panel the circuits are connected to • Whether the control panel is centralized or decentralized

Construction and Installation Phase

Verify that wiring to controls and sensors is installed as specified in the electrical prints and/or CDs.

System Start-Up

Ensure the controls are in the fail-safe position at start-up (Focus on Energy 2004). Verify that sensors are reading the correct value for humidity or dew point by using an independent sensor and document that the conditions are within the design conditions defined in the BoD. Independent sensors must be calibrated using the method specified in section NA7.10 of Reference Appendices for the 2008 Building Energy Efficiency Standards for Residential and Nonresidential Buildings (CEC 2008). For each door or group of doors, check the connections between the controller and anti-sweat heaters: • Verify that there is electrical power supplied to the anti-sweat heater and that the heater is on. • Turn the heater off using the controller. • Verify that the heater has been turned off and that turning the heater off did not affect other loads such as lights or fans, which could indicate incorrect circuiting. With the anti-sweat heaters off, verify the anti-sweat heater control strategy: • At the controller, verify that the setpoints are as specified in the BoD. • Verify the controller output at each setpoint, including minimum/ maximum on-time of the anti-sweat heater and cycle duration. Confirm that the control strategy is sufficient to remove condensation from the door: • Turn anti-sweat heaters back on and return control setpoints to their originally specified values. • Operate the case normally for one hour. • Verify that there is no condensation on the door.

First-Year Operation

108

If specified in the OPR or BoD, monitor anti-sweat controls and sensors and record all alarm events. If continuous monitoring is not specified, at least once per season do the following: • Perform the steps listed in Technical Procedure 5, Verifying Operation of Alarms, to ensure the anti-sweat controller has not been bypassed and that the control strategy is adequate to remove condensation from the door under a variety of conditions.

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Appendix D ~ Technical Procedures

Report faulty or bypassed controls to the building owner, system designer, equipment manufacturer, and/or control manufacturer, as appropriate, so that corrective action may be taken.

8

VERIFYING DEFROST ADEQUACY AND DEFROST CONTROL OPERATION Introduction

Refrigeration systems require a method of defrost to periodically melt ice that accumulates on the coil. Most refrigeration systems have a timer that initiates a defrost cycle at given intervals. A demand defrost control scheme only initiates a defrost cycle when the system determines it is necessary. Defrost also affects the operation of the refrigeration system as a whole. When a system is undergoing defrost, it is generally not contributing to the load on the refrigeration system. However, defrost takes a significant amount of energy and contributes a high heat load, causing the refrigeration system to use more energy to cool down the unit after defrost. Methods of defrosting that require additional piping and valves and also affect system temperatures and pressures include the following: • Circulating hot gas from the compressor through evaporators • Circulating gas from the receiver through evaporators

Planning and Design Phase

Ensure that the OPR specifies the following: • What type of active defrost strategy is used (e.g., hot-gas defrost or electric defrost) • Manufacturer’s defrost specifications for cases or boxes Ensure that the BoD specifies the following: • Defrost schedule for each freezer and staging specifications by refrigeration circuit (see Figures D-3 and D-4).

Figure D-3 Example of Freezer Defrost Schedule Shown in Electronic Controller ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Figure D-4 Example of Defrost Map Indicating Staging of all Circuits on a Rack Shown in Electronic Controller

• For circuits that use electric defrost: • Sizing of any electrical equipment (contactors, breakers, etc.) associated with the circuit and determination that maximum electrical load does not exceed available power supply. • For circuits that use gas defrost: • Type of defrost (e.g., discharge gas or latent gas). • Type of piping (e.g., reverse cycle or three pipe). • Description of any fail-safe measures. • For reverse-cycle gas defrost, include the maximum percentage of the refrigeration load that may be used for gas defrost at any time. Common industry guidelines are that no more than 1/4 to 1/3 of the load may be used for gas defrost (see ASHRAE Handbook—Refrigeration, page 15.19 [2010], and Industrial Refrigeration Handbook [Stoecker 1998]). • Whether demand defrost is used. If so, describe the control strategy. Ensure that the design documents specify the following: • Location of any defrost sensors • Sequence of operations (SoO) for a complete defrost cycle, including the following: • Control setpoints for all steps in the cycle • For equipment without a manufacturer-provided schedule (e.g., walk-in freezers), any time delays programmed into the system, including pumpdown time, fail-safe defrost termination time, drip time, and fan delay • For gas defrost, settings for all valves • If using demand defrost, any conditions that trigger a defrost • For gas defrost, piping schematics and valve specifications

Construction and Installation Phase

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Verify that all sensors are installed according to the design documents. If the system uses hot-gas defrost, verify that valves and piping are installed according to the design documents.

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Appendix D ~ Technical Procedures

System Start-Up

At the controller, verify that control setpoints are as specified in the BoD. For a period of at least 24 h, do the following: • Monitor or record system load profiles to verify that defrost staging is occurring according to the schedule specified in the BoD, including proper termination of defrost. • Log inputs and outputs of the defrost controller and verify that all defrost cycles are occurring according to the sequence in the design documents or the manufacturer’s specifications, including any setpoints and time delays. • If gas defrost is used, verify that the highest observed percentage of the refrigeration load is not greater than the maximum specified in the BoD. • If the system uses demand defrost, examine the inputs and outputs of the controller to verify that the system is initiating defrosts according to the control strategy in the BoD.

First-Year Operation

At least once per season, do the following: • At the controller, verify that control setpoints are as specified in the BoD. If control setpoints have been changed, report findings to the building owner and/or system designer to determine the reason. If necessary, update the documentation. • For a period of 24 h, do the following: • Monitor or record system load profiles to verify that defrost staging is occurring as specified in the BoD, including proper termination of defrost. Note in exception logs any systems that reach the fail-safe setting before terminating defrost on temperature. • Log inputs and outputs of the defrost controller and verify that all defrost cycles are occurring according to the sequence in the design documents or the manufacturer’s specifications, including any setpoints and time delays. • If gas defrost is used, verify that the highest observed percentage of the refrigeration load is not greater than the maximum specified in the BoD. • If the system uses demand defrost, examine the inputs and outputs of the controller to verify that the system is initiating defrosts according to the control strategy in the BoD. • Visually check a sample of freezer cases or boxes (~10%) for the following defrost-related problems: • Ice on the coil that is not removed by defrost • Ice in the drain pan or a loose drain pan • Defrost meltwater or ice on the floor or product below the evaporator • Ice on distributor capillary tubes • Report problems to the building owner, system designer, and/or equipment manufacturer, as appropriate, so that corrective action may be taken. Include in the report any systems that reach the failsafe setting before terminating defrost on temperature.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

9 MINIMIZING AIR INFILTRATION OF BOXES AND CASES Introduction

This technical procedure applies to walk-in boxes and refrigerated cases, both closed and open. Walk-in boxes are often built on site and, if not constructed properly, can experience warm air infiltration through gaps in the panels that make up the box and around the door. Closed display cases are typically built in a factory and shipped as a single unit but may sustain damage that compromises their airtightness. Many walk-in doors also include a method of reducing infiltration when doors are open, such as strip curtains. Open cases are, by definition, open to the ambient air, but a continually flowing air curtain is used to reduce heat transfer to the extent possible. This procedure verifies that air infiltration is minimized for walk-in boxes and refrigerated cases.

Planning and Design Phase

Ensure that the OPR specifies the following: • Plans, specifications, and installation instructions for any equipment built on site Ensure that the BoD specifies the following: • Characteristics of infiltration-reducing devices, such as air curtains, strip curtains, or automatic closers on walk-in and reach-in doors or night curtains on open cases

Construction and Installation Phase

During the Construction and Installation Phase, verify that walk-ins constructed on site are built according to the specifications in the BoD. Ensure that joints, conduit penetrations, and other penetrations exposed to non-refrigerated air are sealed with silicone, any holes are filled, and infiltration-reducing devices are installed on walk-in and reach-in doors as specified. For walk-ins supplied without a floor, verify that any gaps between the wall panels and the floor are filled. For open cases, visually check that shelving does not extend into the plane of the air curtain. If night curtains have been specified, verify that they are included and properly installed.

System Start-Up

During the Start-Up and First-Year Operation Phase, check for points of heat loss that could indicate air infiltration: • Visually inspect the exterior of walk-in boxes and reach-in cases for condensation, which could indicate an air leak. • Verify that all refrigerated case and walk-in box joints have been sealed according to manufacturer’s recommendations. • Verify that all reach-in glass doors close and seal properly. • If feasible, use an infrared camera or other device to detect air leakage. Key areas to scan include the following: • Window and door seals. • Walk-in box panel and refrigerated case joints. • For walk-ins without factory-installed floors, the wall-to-floor interface.

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Appendix D ~ Technical Procedures

• Holes made for refrigerant piping, electrical conduit, or any other purpose. • For equipment with a self-contained refrigeration system, the wall panel surrounding the refrigeration unit. • Verify integrity of any open-case air curtains (using, for example, a smoke test). If air infiltration is detected, report findings to the building owner and refrigeration engineer so that corrective action may be taken.

First-Year Operation

At the end of the first year, do the following: • Visually inspect boxes and cases for any damage they may have sustained during use, including the following: • Air gaps caused by dents or punctures in the walls. • Missing or damaged gasketing around doors. • Damage to door frames. • Misaligned doors or doors that do not seal completely. • For walk-in doors, missing or damaged floor sweep (gasket at bottom of door). • Missing or damaged strip curtains, if specified. • Missing or damaged night curtains, if specified. • Visually inspect the exterior of walk-ins and refrigerated cases for condensation and inspect the interior for ice buildup on the inner wall, which could indicate an air leak. • Visually check that shelving or merchandise is not blocking the plane of the air curtains on open cases. • If feasible, use an infrared camera or other device to detect air leakage according to the procedure in Technical Procedure 5, Verifying Operation of Alarms. If air infiltration is detected, report findings to the building owner and refrigeration engineer so that corrective action may be taken.

10

EVALUATING THE USE OF ENERGY-SAVING FEATURES Introduction

Commercial refrigeration systems may incorporate a wide range of energy-saving features, subsystems, and components, varying greatly depending on the system type and intended usage. These features can range from components installed in individual pieces of equipment, such as advanced lighting or high-efficiency fans, to componentry that drives the performance of the entire system, such as system-level controls. Each piece of equipment included in the system, such as the compressor rack, display cases, walk-ins, condenser, piping, etc., will likely have its own set of features to be considered during planning, construction, and operation. This procedure outlines general methods for evaluating these features and contains instructions for revising the Commissioning Plan as necessary to address these features.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

Planning and Design Phase

Ensure that the OPR specifies the following: • Any high-level corporate sustainability goals • Any specific technology-related initiatives related to energy efficiency (e.g., light-emitting diode [LED] lighting) or carbon emissions reduction (e.g., carbon dioxide refrigerant) • City and state of the system installation and any accompanying factors such as climate, energy prices, regulatory bodies, rebates, etc. • Cost constraints and/or acceptable payback period Ensure that the BoD specifies the following: • Documentation of how energy-efficient features were chosen based on the requirements or information in the OPR. Typically, this takes the form of an economic analysis for each feature that estimates the overall installed (capital) cost for each system component and optional feature as well as calculated operating cost and payback period estimates, considering the following: • Procurement, installation, commissioning, and operational costs—including energy costs—of each piece of equipment and technological feature. • Estimates of local electricity rates. • Expected energy and cost savings. • Rebate programs and other incentives available from utilities and government organizations. • Description of the system’s planned operating profile and the characteristics of the environment in which it will be used, along with an explanation of how this helps drive the selection of features and whether any technologies whose operating profiles would not be well aligned with those of the system are discarded from consideration. Ensure that the design documents specify that instrumentation and associated provisions for the wiring needed in the field for verification of performance of energy-efficient technologies. The system designer should engage in an iterative process during the development of the BoD and design documents to ensure that the selected componentry maximizes energy efficiency while remaining within the cost and performance requirements of the project. As needed, update the Commissioning Plan to include commissioning procedures for each technology introduced that is not covered in the existing Commissioning Plan. If an existing system is being retrofitted or modified, update the OPR, BoD, and design documents to reflect changes to the system during the retrofit project.

Construction and Installation Phase

114

During the Construction and Installation Phase, follow the steps outlined in the Commissioning Plan to verify that energy-saving features are constructed properly. Make any necessary changes to the Construction and Installation Phase of the Commissioning Plan if required for any of the energysaving features.

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Appendix D ~ Technical Procedures

System Start-Up

During the Start-Up and First-Year Operation Phase, follow the steps outlined in the Commissioning Plan to verify that energy-saving features are operating properly. Make any necessary changes to the Start-Up and FirstYear Operation Phase of the Commissioning Plan if required for any of the energy-saving features. For example, if a heat reclaim system is used, verify that the controls of the heat reclaim system direct high-side refrigerant flow to the heat reclaim heat exchanger when there is a demand for heating. Verify the operation of any data collection systems that quantify the operating characteristics and profile of each of the subsystems analyzed. Data collection systems could range from visual inspection of operating properties to electronic collection of operating parameter data, depending on the system. In particular, focus on collecting data that will help quantify energy savings due to implementing specific features. Ensure that data collection procedures are included in the Commissioning Plan.

First-Year Operation

During the first year of operation, follow the steps outlined in the Commissioning Plan to verify that energy-saving features are operating properly. Make any necessary changes to the First-Year Operation section of the Commissioning Plan if required by any of the energy-saving features. If data collection systems are employed, collect data that represent a complete record of the system’s operating profile. At the one-year mark, undertake a performance review with focus placed on the operation of energy-saving features specified in the BoD. Compare the data to the design plans from the planning phase of the process, conducting a head-to-head comparison of the individual parameters and field performance measured for each subsystem or feature to those anticipated in the design. Provide feedback to the designer through measured performance parameter data. If there is evidence of any significant degradation of performance or other deviation from the expected operation, further evaluate the system with input from the system designer. If possible, use the data to estimate the in-field energy savings due to particular features.

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Glossary

The definitions provided in this Guide include terms that, while not necessarily used in this Guide, are commonly used in refrigeration commissioning practice. azeotrope, azeotropic refrigerant

A mixture of refrigerants whose vapor and liquid phases in equilibrium have identical compositions (the boiling point is constant). Figure G-1 is a refrigerant property diagram for single-component or azeotropic refrigerant blends.

air curtain

Device that produces steady airflow across the plane of an opening, intended to minimize heat transfer between two spaces.

air-cooled condenser

A refrigerating system component, including condenser fans, that condenses refrigerant vapor by rejecting heat to air mechanically circulated over its heat transfer surface, causing a temperature rise in the air.

Graphic courtesy of NREL; credit Alfred Hicks

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Figure G-1 Refrigerant Property Diagram—Azeotropic

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

alarm

A device that detects a system occurrence or characteristic and provides an alert or notification. The notification may take the form of a light, sound, email, or other form. Types of alarms include anticipatory, energy, and safety or operation alarms. anticipatory alarms

Devices that provide notification of system conditions that, although not themselves harmful, could develop into harmful situations. An example is an alarm that notifies the operator of an elevated rate of compressor cycling, which could indicate that compressor maintenance is required to prevent failure.

energy alarms

Devices that provide notification of conditions that could result in high component or system energy use. Examples include alarms that notify the operator of a walk-in box door left open, refrigerant suction pressure not within specification or, for water-cooled condensers, high condenser-water temperature.

safety or operation alarms

Devices that provide notification of conditions that are likely to cause immediate harm to the system, system operators, or product being stored. Examples include alarms that notify the operator of elevated case and cooler temperatures, refrigerant leakage, refrigerant head pressure outside safe operating ranges, or low levels of refrigerant oil.

analysis points

Sets of conditions corresponding to different physical scenarios affecting both load and capacity, used to evaluate capacity control of the system.

anti-sweat heater

Wire or other device that heats the frame or glass of a transparent door to reduce or eliminate condensation.

annual baseline log (ABL)

The owner record of system operating control parameters and performance metrics.

approach (temperature)

Temperature difference (TD). See also condenser temperature difference (TD) and evaporator temperature difference (TD).

condenser approach temperature

The difference between the condensing temperature (based on the refrigerant pressure entering the condenser) and the ambient air temperature entering the condenser.

design condenser approach temperature

The approach temperature at which the condenser was designed to operate when operating at the design ambient air temperature and the design capacity.

balancing valve

A device for maintaining a set flow of a fluid, often used in secondary refrigeration and water-cooled condensing systems.

Basis of Design (BoD)

A document that records the concepts, calculations, decisions, and product selections used to meet the Owner’s Project Requirements (OPR) and to satisfy applicable regulatory requirements, standards, and guidelines. The document includes both narrative descriptions and lists of individual items that support the design process.

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Glossary

bin analysis

A simplified energy analysis method by which the hourly energy use is calculated for the average temperature within several sets of outdoor temperature ranges (bins) and multiplied by the annual (or monthly) hours in each range.

bubble-point temperature

Refrigerant liquid’s saturation temperature at a specified pressure. For a zeotropic refrigerant blend, the bubble point, which is colder than the dew point, is the temperature at a specified pressure where a liquid begins to evaporate (in an evaporator) as well as the temperature at a specified pressure where the refrigerant finishes condensing (in a condenser).

capacity steps

Discrete levels of capacity that the system is designed to maintain. The number of steps is based on the number of compressors and unloaders (if used) and how they are staged.

carbon dioxide (CO2 )

A refrigerant used in primary and secondary systems. As a refrigerant, an industrial grade or higher quality is often used.

Commissioning Plan

A document that outlines the organization, schedule, allocation of resources, and documentation requirements of the commissioning process.

commissioning (Cx), commissioning process

A quality-focused process for enhancing the delivery of a project. The process focuses on verifying and documenting that the facility and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the Owner’s Project Requirements (OPR).

commissioning authority (CxA)

An entity identified by the owner who leads, plans, schedules, and coordinates the commissioning team to implement the commissioning process.

compressor staging

System for operating only certain compressors at one time to maintain different system capacity steps.

condenser holdback valve

The device that limits the minimum condensing pressure for the refrigeration system (flooding valve, low-ambient valve, drop-leg valve, drain-leg regulator).

condenser temperature difference (TD)

The difference between the saturated condensing temperature (SCT) and the entering air dry-bulb temperature for air-cooled condensers or entering air wet-bulb temperature for evaporative condensers.

control system

The combination of components/hardware, field wiring, software, and programming that monitors the system via input signals and then governs the operation of the system via output signals.

compressor discharge pressure

Pressure of refrigerant gas at the compressor outlet.

compressor discharge temperature

Temperature of refrigerant gas at the compressor outlet.

continuously variable unloading

Compressor capacity (CC) modulation achieved via digital output control that provides fine increments of capacity control over the range of maximum capacity down to full capacity.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

defrost demand defrost

Defrost control strategy that does not initiate a defrost on a set schedule but initiates defrost automatically based on other system parameters.

electric defrost

Defrost method that uses heated rods embedded in the evaporator coil to melt ice from the coil during defrost.

gas defrost

Method of defrost that circulates discharge from the compressor rack or saturated gas from the receiver through the evaporator coil to melt ice on the coil.

off-time defrost

Also called air defrost. Defrost method used for units whose interior temperature is above freezing, which involves melting any ice from the evaporator coil by running the fans during the refrigeration system’s off cycle (i.e., when refrigerant is not circulating through the coil).

reverse-cycle

gas defrost

Method of gas defrost piping that reverses the flow of refrigerant in the suction line to the evaporator coil.

three-pipe gas defrost

Method of gas piping that uses a separate defrost gas supply line to the evaporator coil in addition to liquid and suction lines.

design ambient air temperature

The highest outdoor air temperature at which the system is designed to meet the design load.

design capacity

The maximum refrigerating capacity that the system is designed to supply when operating at the design ambient air temperature. The design capacity typically exceeds the design load to accommodate losses in interconnecting piping and provide a safety factor.

design load

The maximum refrigerating load that the system is designed to accommodate while maintaining the design setpoint temperatures in cases and coolers connected to the system.

design setpoint temperatures

The maximum temperatures of the cases and coolers connected to the system that the system is designed to maintain while meeting the design load.

dew-point temperature

Refrigerant vapor’s saturation temperature at a specified pressure. For a zeotropic refrigerant blend, the dew point, which is warmer than the bubble point, is the temperature at a specified pressure where a liquid finishes evaporating (in an evaporator) as well as the temperature at a specified pressure where the refrigerant begins to condense (in a condenser).

psychrometric dew point

Temperature at or below which condensation forms on a surface.

discharge air temperature (DAT) evaporator discharge air temperature

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Temperature of air leaving a unit cooler.

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Glossary

refrigerated case discharge air temperature

Temperature of air discharged from a refrigerated case discharge air grille.

direct expansion (DX)

Evaporator arrangement whereby liquid refrigerant is fed through an expansion valve or metering device and is designed to evaporate completely before leaving the evaporator as vapor.

distributed refrigeration system

A system wherein compressors and condensers are packaged with, or located near, the display cases or coolers that they service.

drip time

Time between when defrost is terminated and when refrigeration restarts.

drop-leg pressure

Pressure of refrigerant in the condenser drain line or the pipe between the condenser and the high-pressure receiver.

drop-leg temperature

Temperature of refrigerant in the condenser drain line or the pipe between the condenser and the high-pressure receiver.

embedded controls

Controls that the original equipment manufacturer (OEM) packages with the equipment at the factory.

evaporator return air temperature (RAT)

Temperature of air returning to an evaporator from the refrigerated space.

evaporator temperature difference (TD)

The difference between the saturated evaporator temperature (SET) and the return air dry-bulb temperature. For zeotropic refrigerants, the average temperature difference is the difference between the average coil temperature and the return air dry-bulb temperature. (Note: In an evaporator, the midpoint temperature does not represent the average coil temperature due to the reduction in refrigerant quality through the expansion valve.)

evaporatively cooled condenser

A self-contained refrigeration system component that condenses refrigerant vapor by rejecting heat to water and air, which are mechanically circulated over the condenser’s heat transfer surface, thereby causing evaporation of the water and an increase in enthalpy of the air.

fail-safe defrost termination time

Time at which defrost will terminate if no other signal to terminate has been received.

failure detection and diagnostics (FDD)

Automated means by which to sense actual or impending failures of equipment or components and alert the appropriate individuals. Commonly called fault detection and diagnostics but rephrased here to avoid confusion with electrical faults. In this context, the fault can be any equipment fault or failure, including, but not limited to, electrical faults.

fan delay

Time between when the refrigeration restarts and the fans restart.

floating low-side pressure

Means by which the low-side pressure is adjusted to operate the refrigeration system at the highest low-side pressure that adequately maintains the setpoint temperatures in cases and coolers. Also known as floating suction pressure.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

floating high-side pressure

Means by which the high-side pressure is adjusted to maintain a target temperature approach in the condenser. This allows the refrigeration system to operate at higher efficiencies when the outdoor temperature is below the design outdoor temperature. Also known as floating head-pressure control.

gasketing

Flexible seal between two components of a box or case, such as between a door and a door frame.

glide

The absolute value of the difference between the starting and ending temperatures of a phase-change process (condensation or evaporation) for a zeotropic refrigerant exclusive of any liquid subcooling or vapor superheating (AHRI 2008).

glycol

Propylene glycol, generally diluted with water to approximately 35% by volume, used as a secondary fluid.

heat reclaim

The heat transfer subassembly to the refrigeration system that uses some/all of the heat available in the discharged refrigerant gas out of the compressor(s).

input/output (I/O)

The list of control input and output devices with descriptive naming used to connect the system hardware with the control system.

interval data

Time-series energy data from a meter (typically electrical, but could be natural gas or water). Most often reported in 15 min intervals. Many electric utilities can provide these data to commercial customers upon request. Alternatively, a utility customer may measure and record similar data to better understand energy-use characteristics and to help identify opportunities for improved energy efficiency.

issues log

A formal and ongoing record of problems or concerns—and their resolution— that have been raised by members of the commissioning team during the course of the commissioning process.

leaving gas temperature (LGT)

Temperature of refrigerant gas at the boundary of the refrigerated space, used to determine the productive refrigeration work accomplished by the refrigerant mass flow.

mechanical safeties

Mechanically operated pressure switches and thermostats used for compressor safety protection, which may be in addition to electronic controls with safety functions.

midpoint temperature

For zeotropic refrigerants, the average of the refrigerant’s bubble-point and dew-point temperatures at a specified pressure.

multiplex refrigeration system

A system wherein compressors are located in a machine room remote from the display cases and coolers that they service.

net refrigeration effect (NRE)

The refrigerating capacity available for space or process cooling equal to the mass flow of the refrigerant and the enthalpy difference at the boundary of the refrigerated space or cooling process.

operating parameters

Control setpoints and schedules that govern the function of the unit or system.

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Glossary

overfeed ratio

The mass ratio of liquid to vapor at the outlet of a liquid overfeed unit cooler. This may also be referred to as overfeed rate.

Owner’s Project Requirements (OPR)

A document that details the functional requirements of a project and the expectations of how it will be used and operated. This includes project goals, measurable performance criteria, cost considerations, benchmarks, success criteria, and supporting information. The term Project Intent is used by some owners for their commissioning process instead of Owner’s Project Requirements.

primary refrigerant

Working fluid in a refrigerating cycle (as opposed to a secondary refrigerant).

pulse-width modulation

Method of heater control that “pulses” heaters on for a percentage of a specified cycle time (typically only a matter of seconds).

pumpdown time

Time between when the refrigeration is stopped and the defrost is initiated.

return gas temperature (RGT)

Temperature of refrigerant gas at the compressor suction inlet.

saturated condensing temperature (SCT)

For single-component and azeotrope refrigerants, the saturation temperature corresponding to the refrigerant pressure at the condenser entrance. For zeotropic refrigerants, the arithmetic average of the dew-point and bubble-point temperatures (midpoint) corresponding to the refrigerant pressure at the condenser entrance (AHRI 2005). SCT is often referred to simply as condensing temperature.

saturated evaporator temperature (SET)

Refrigerant temperature at the unit cooler inlet or outlet determined either by measuring the temperature at the outlet of the two-phase refrigerant flow (for a liquid overfeed unit cooler) or by measuring refrigerant pressure and determining the corresponding temperature from reference thermodynamic tables or equations for the refrigerant. For zeotropic refrigerants, the corresponding temperature to a measured pressure is the refrigerant dew point (AHRI 2008).

saturated suction temperature (SST)

The equivalent saturation temperature of a refrigerant corresponding to the pressure at a specified location, such as at the compressor inlet, the suction manifold, or other suction location. For zeotropic refrigerants, the compressor saturated suction temperature is normally defined as the dew-point temperature.

saturation temperature

The equilibrium temperature of a pure refrigerant or an azeotropic refrigerant in a two-phase mixture of a vapor and liquid at a given pressure.

secondary fluid

A fluid of known properties (e.g., water, steam, or brine) that is used as a cooling medium.

secondary refrigerant

A volatile refrigerant (usually a single refrigerant or an azeotropic mixture) of known properties that is used as a cooling medium.

secondary refrigeration system

The system and method of chilling and circulating a secondary fluid within a primary refrigeration system to transport the heat from the load to the primary refrigeration system. The secondary fluid may also be a secondary refrigerant where some evaporation takes place at the load.

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

self-contained refrigeration

Refrigeration system that consists of the unit cooler and condensing unit connected by the manufacturer as one piece of equipment.

strip curtain

Barrier made of plastic strips that spans a doorway to minimize air infiltration when the main door is open.

subcooling

Cooling a refrigerant to a temperature below the saturation temperature for a given pressure. Expressed as the temperature difference (TD) between the saturation temperature at that pressure and the liquid temperature at the same location. For a zeotropic refrigerant, the bubble point is used as the saturation temperature.

subcooler

A heat exchanger for cooling liquid refrigerant below its condensing temperature at a given pressure. For a zeotropic refrigerant, the bubble point is used as the saturation temperature.

submittal

The document exchanged from the equipment manufacturer or contractor to the design professional that illustrates equipment definitions, capacities, layouts, utility requirements, equipment weights, piping and instrumentation diagrams, etc.

suction pressure

Pressure of refrigerant gas at the compressor suction header or compressor inlet.

suction temperature

Temperature of suction refrigerant gas.

superheat

The difference between the vapor temperature and the saturation (dew-point) temperature at a defined pressure. It exists wherever in the system the temperature is higher than saturation (direct-expansion evaporator, suction line, compressor discharge, etc.).

system energy baseline (SEB)

Annualized electrical energy consumption calculation for the system based on the local weather data, system capacity, and operating control parameters.

test, adjust, and balance (TAB)

The process of balancing/documenting pressures and flows through control valves of cooling coils and heat exchangers in hydronic systems, such as water-cooled condensers and secondary glycol refrigeration systems.

training plan

A document that details the expectations, schedule, budget, and deliverables of commissioning process activities related to training of project operating and maintenance personnel and users.

trunk (loop) refrigeration system

A variation of the multiplex system in which common liquid lines and suction lines (trunks) run refrigerant to the vicinity of each case or cooler supplied by the system. Refrigerant lines (loops) branch off from these trunk lines to service each case or cooler.

unit cooler

A factory-made cabinet incorporating a finned refrigerant-to-air heat exchanger and circulation fans, used in freezers or cooler walk-in boxes. May also be called an evaporator coil or, in industrial applications, is often referred to as air unit.

unloader

The solenoid-operated capacity control device that is attached to/within the compressor to reduce capacity in steps.

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Glossary

Graphic courtesy of NREL; credit Alfred Hicks

Figure G-2 Refrigerant Property Diagram—Zeotropic

variable capacity controller

The device that regulates the refrigeration system’s compressor capacity (CC) control device(s) within the defined control limits.

walk-in box

The enclosure of a walk-in cooler or freezer, comprising the walls, solid walkin doors, glass reach-in display doors, ceiling, and floor.

water-cooled condenser

A condenser that removes the heat of the refrigerant by heat transfer fluid flowing inside heat exchanging surfaces.

zeotrope, zeotropic refrigerant

Refrigerant blend comprising multiple components of different volatilities that, when used in refrigeration cycles, change volumetric composition and saturation temperatures as they evaporate (boil) or condense at constant pressure. Figure G-2 is a refrigerant property diagram for zeotropic blends, showing the effect of boiling point transition or “glide” as an aid to understanding this definition.

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References

AHRI. 2004. ANSI/AHRI Standard 540-2004: Performance Rating of Positive Displacement Condensing Units. Arlington, VA: Air-Conditioning, Heating, and Refrigeration Institute. AHRI. 2005. ANSI/AHRI Standard 460-2005: Performance Rating of Remote Mechanical-Draft Air-Cooled Refrigerant Condensers. Arlington, VA: Air-Conditioning, Heating, and Refrigeration Institute. AHRI. 2008. ANSI/AHRI Standard 420-2008: Performance Rating of ForcedCirculation Free-Delivery Unit Coolers for Refrigeration. Arlington, VA: Air-Conditioning, Heating, and Refrigeration Institute. ASHRAE. 2005. ASHRAE Guideline 0-2005, The Commissioning Process. Atlanta: ASHRAE. ASHRAE. 2007. ASHRAE Guideline 1.1-2007, HVAC&R Technical Requirements for the Commissioning Process. Atlanta: ASHRAE. ASHRAE. 2010. ASHRAE Handbook—Refrigeration. Atlanta: ASHRAE. ASHRAE. 2011. ANSI/ASHRAE/USGBC/IES Standard 189.1-2011, Standard for the Design of High-Performance Green Buildings Except LowRise Residential Buildings. Atlanta: ASHRAE. ASHRAE. 2013a. ASHRAE Handbook—Fundamentals. Atlanta: ASHRAE. ASHRAE. 2013b. ANSI/ASHRAE/IES Standard 90.1-2013, Energy Standard for Buildings Except Low-Rise Residential Buildings. Atlanta: ASHRAE. ASHRAE. 2013c. ANSI/ASHRAE Standard 147-2013, Reducing Release of Halogenated Refrigerants from Refrigerating and Air-Conditioning Equipment and Systems. Atlanta: ASHRAE. CA. 2013a. California Green Building Standards Code (CALGreen). Sacramento: State of California. CA. 2013b. 2013 California Mechanical Code, California Code of Regulations Title 24, Part 4. Sacramento: State of California. CEC. 2008. Reference Appendices for the 2008 Building Energy Efficiency Standards for Residential and Nonresidential Buildings. Appendix NA-7: Acceptance Requirements for Nonresidential Buildings. Sacramento, CA: California Energy Commission. www.energy.ca.gov/2008publications/ CEC-400-2008-004/CEC-400-2008-004-CMF.PDF ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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Refrigeration Commissioning Guide for Commercial and Industrial Systems

DOE. 2009. Energy Savings Potential and R&D Opportunities for Commercial Refrigeration. Washington, DC: U.S. Department of Energy. http:// apps1.eere.energy.gov/buildings/publications/pdfs/corporate/ commercial_refrig_report_10-09.pdf EPA. 2007. Supermarket Energy Use Profile. Washington, DC: U.S. Environmental Protection Agency. www.mgaeeip.com.au/uploads/1/8/9/6/189631 83/doe_supermarket_energy_use_profile.pdf EPA. 2011a. GreenChill Best Practices Guideline: Commercial Refrigeration Leak Prevention & Repairs. EPA bulletin 430-b-11-001. Washington, DC: U.S. Environmental Protection Agency. www2.epa.gov/sites/production/ files/documents/leakpreventionrepairguidelines.pdf EPA. 2011b. GreenChill Best Practices Guideline: Ensuring Leak-Tight Installations of Commercial Refrigeration Equipment. Washington, DC: U.S. Environmental Protection Agency. www2.epa.gov/sites/production/ files/documents/GChill_LeakTightEquipInstall.pdf Focus on Energy. 2004. Anti-sweat heater controls: Technical data sheet. Madison, WI: Focus on Energy. ICC. 2012a. International Energy Conservation Code. Washington, DC: International Code Council. ICC. 2012b. International Green Construction CodeTM. Washington, DC: International Code Council. Maxson, S. 1995. Oil pressure problems in refrigeration systems. Tech·Topics 3(1). www.heatcraftrpd.com/res/pdfs/faqs/HRP_TechTopic_OilPressure Problems.pdf PECI. 2010. Grocery Store Commissioning. Presentation to the National Conference on Building Commissioning by Portland Energy Conservation, Inc. www.bcxa.org/ncbc/2010/documents/presentations/ncbc-2010grocery_store_commissioning-moore.pdf Stoecker, W. 1998. Industrial Refrigeration Handbook. New York: McGrawHill Professional. U.S. Congress. House. Emergency Planning and Community Right-to-Know Act of 1986. HR 2005. 99th Cong.

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Bookstore The ASHRAE Bookstore is a one-stop shop for all ASHRAE publications, including books, standards, guidelines, Handbook volumes, CDs, DVDs, and additional electronic resources. These publications provide important information for engineers, architects, and others covering HVAC&R design and application as well as cutting-edge topics such as sustainability, building performance and commissioning, energy efficiency, and indoor air quality. ASHRAE members are entitled to discounts on many ASHRAE publications. Visit www.ashrae.org for more information on the many benefits ASHRAE membership has to offer.

Additional ASHRAE resources: • ANSI/ASHRAE/IES Standard 202-2013, Commissioning Process for Buildings and Systems • ASHRAE Guideline 0-2005, The Commissioning Process • ASHRAE Guideline 1.1-2007, HVAC&R Technical Requirements for the Commissioning Process • ASHRAE Handbook—Refrigeration (More than 750 pages covering equipment and systems for cooling, freezing, and storing food; industrial applications of refrigeration; and low-temperature refrigeration.) • ANSI/ASHRAE Standard 15-2013, Safety Standard for Refrigeration Systems • ANSI/ASHRAE Standard 34-2013, Designation and Safety Classifation of Refrigerants • ANSI/ASHRAE Standard 147-2013, Reducing Release of Halogenated Refrigerants from Refrigerating and Air-Conditioning Equipment and Systems ThisfileislicensedtoChrisBerry([email protected]).ASHRAEREFCXDownloadDate:3/17/2014

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The Essential Guide for Commissioning Refrigeration Systems

Because deficiencies in system design found at start-up are not easily resolved, maintenance managers or operators may deal with unnecessary shortcomings and expenses over the life of the facility. Commissioning helps project teams avoid these “surprises” by establishing a consistent, stepwise process that helps “get it right the first time.” The commissioning process starts with the initial planning and design and continues through construction, installation, start-up, and the first year of system operation. Commissioning also sets the stage for ongoing servicing and maintenance of performance. The result is refrigeration systems that are easier and less expensive to install and maintain, with lower energy costs, minimized liabilities from refrigeration system leaks, and reduced loss of refrigerated product due to system failures or unreliable performance. Using this Guide will help achieve cost-effective and cost-efficient refrigeration systems for new projects, expansions, remodels, and existing systems that simply need a tune-up.

Refrigeration Commissioning Guide for Commercial and Industrial Systems

The first of its kind, Refrigeration Commissioning Guide for Commercial and Industrial Systems provides guidance to owners and managers of commercial and industrial facilities that use refrigeration systems to help ensure that project requirements are met and owners’ expectations are achieved. For commercial facility owners and managers, this means improved profitability through lower operating and service costs as well as reduced product loss.

Refrigeration Commissioning Guide for Commercial and Industrial Systems

Commissioning Refrigeration Systems in

ASHRAE 1791 Tullie Circle Atlanta, GA 30329-2305 404-636-8400 (worldwide) www.ashrae.org

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Product code: 90315 12/13

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• Food Retail and Convenience Stores • Small Retail Stores • Food and Beverage Facilities • Food Distribution Centers • Industrial Plant Applications