Thermal Rehabilitation (Azuma House)

Thermal Rehabilitation Group 5: Real Estate Technology Time brings changes always. Same is the case with building sector. Once the emphasis was on the aesthetics and soundness of the buildings but now a day, we are more concerned about the Sustainability and thermal efficiency of buildings. This report follows the same pattern that how buildings can be rehabilitated to increase their thermal efficiency, to reduces the energy consumption and to cut down carbon footprints. Building chosen for the task is “Azuma House” located in Osaka, japan. The building type is concrete rectangular box house and represents a league of housing sector that belongs to 70’s and 80’s. Building is first introduced and diagnosed then its thermal performance is evaluated. After evaluation rehabilitation measures are selected upon the criteria of sustainability, affordability, feasibility, durability and comfort. This document shows that how building belongs to same type can be rehabilitated effectively .

TABLE OF CONTENTS 1.

BUILDING’S INTRODUCTION AND DIAGNOSIS .................................................................... 3 1.1.

Introduction of Building .......................................................................................................... 3

Situation in locality .......................................................................................................................... 4 Climate............................................................................................................................................. 4 1.2.

Building’s Detailed Description and Analysis .......................................................................... 5

1.3.

Thermal flow study of Azuma House ...................................................................................... 6

2. Building Evaluation (w.r.t energy consumption and CO2 emission) – Before Rehabilitation ........ 7 2.1. Building energy codes .................................................................................................................. 7 2.2 Parameters to calculate Building Energy Consumption ................................................................ 8 2.3 The Calculation Method: ............................................................................................................. 10 2.3.1. Degree-day method............................................................................................................. 10 2.3.2. Principle of the heating degree-day method: ..................................................................... 11 2.3.3. Heating degree days ............................................................................................................ 11 2.3.4. Calculation of U values ........................................................................................................ 13 2.3.5. Formula to calculate of the Heat Losses ............................................................................ 14 2.3.6. Formula to calculate of the Heating energy consumption.................................................. 14 2.4. Building simulation method for calculating the energy consumption ....................................... 15 2.4.1. MIT Design Advisor .............................................................................................................. 15 2.4.2. Weather Data ...................................................................................................................... 16 2.4.3. Calculations ......................................................................................................................... 16 2.4.3. Ventilation ........................................................................................................................... 17 2.4.4. Cooling Loads....................................................................................................................... 17 2.4.5. Heating Loads ...................................................................................................................... 18 2.4.6. Building Envelope ................................................................................................................ 18 2.4.6.1. Roof .................................................................................................................................. 18 2.4.7. Energy Balance .................................................................................................................... 18 2.4.8. Building Information ........................................................................................................... 19 2.4.9. Simulation Results ............................................................................................................... 19 2.4.10. Energy ................................................................................................................................ 21 2.4.11. Life cycle Cost .................................................................................................................... 21 3. REHABILITATION MEASURES AND RECOMMENDATIONS ..........................................................22 3.1. Thermal Insulation...................................................................................................................... 22 3.2. Insulation Target......................................................................................................................... 22 3.3. Wall Insulation ............................................................................................................................ 23 1

3.3.1. Cavity Wall Insulation .......................................................................................................... 23 3.3.2. Solid Wall Insulation ............................................................................................................ 23 3.3.3. Comparison of Different Wall Insulation ............................................................................. 26 3.4. Roof Insulation ........................................................................................................................... 26 3.4.1. Flat Roof .............................................................................................................................. 26 3.5. Floor Insulation........................................................................................................................... 28 3.5.1. Floor Insulation Methods .................................................................................................... 28 3.6.

Draught Proofing ................................................................................................................... 32

3.7.

Selection Criteria for Insulation Material .............................................................................. 32

3.8.

Recommendations................................................................................................................. 33

3.9.

Solar Shading Systems ........................................................................................................... 34

3.9.1.

Venetian Blinds .............................................................................................................. 35

3.9.2.

Roller Shutters ............................................................................................................... 36

3.9.3.

Horizontal solar fins ....................................................................................................... 36

3.10.

Recommended System ...................................................................................................... 36

4. Building energy consumption – After Refurbishment ................................................................37 4.1.

Results of MIT design Software ............................................................................................. 37

4.1.1.

Building Information:..................................................................................................... 37

4.1.2.

Primary Energy Use and CO2 Emissions ........................................................................ 38

4.2.

Results of Heating Degree Days Method .............................................................................. 40

5.

Thermal bridges ...............................................................................................................42

6.

FINANCIAL ANALYSIS OF THE REHABILITATION..................................................................43 6.1.

Financial Analysis ................................................................................................................... 43

6.2.

Estimation of Investment: ..................................................................................................... 44

6.3.

Savings ................................................................................................................................... 44

6.4.

Yield & Pay Back period (Static): ........................................................................................... 44

6.5.

Net Present Value (Dynamic Calculation): ............................................................................ 45

7. Conclusion...............................................................................................................................46

2

1. BUILDING’S INTRODUCTION AND DIAGNOSIS 1.1.

Introduction of Building

The building on which we work is Row House in Sumiyoshi also called Azuma House. It is a personal residence in Sumiyoshi-ku, Osaka, Japan. It was designed by Japanese architect Tadao Ando in his early career. The climate of the city where the Azuma row house is located is semitropical, and currently has four different seasons, like European countries.1 Site area: 57 sq meters Built area: 34 sq meters (patio in the centre) Total floor area: 65 sq meters term of planning: 1/1975-8/1975 term of construction: 10/1975-2/1976 Latitude: 34.6106 Longitude: 135.4922

3

Figure 1: Model of Azuma house, Osaka

The Azuma House in Sumiyoshi is one of the earliest works of the self-taught architect Tadao Ando. Thanks to the Azuma House, Ando received an award from the Japan Association of Architecture in 1976. Although it is simple yet a great design but its thermal efficiency is poor. This may happen because the expectations of users changes and now we are much more concerned about carbon footprints and sustainable development.4

1

Francesco Dal Co. Tadao Ando: Complete Works. Phaidon Press, 1997. ISBN 0-7148-3717-2

2

http://www.greatbuildings.com/buildings/Azuma_House.html accessed on June20, 2013 http://www.turbosquid.com/3d-models/azuma-house-tadao-ando-3d-model/198176 accessed on June20,2013 4 http://en.wikiarquitectura.com/index.php/Azuma_House accessed June21, 2013 (11:54) 3

3

Situation in locality Azuma house changed the trend in the locality, where wooden houses were found all around. While this area is not the most chaotic of the city, there is a clear contrast between this "concrete box" and its surrounding buildings.5 Climate Osaka belongs to a semi-tropical zone and has a gift of four seasons. Its winters are generally mild, having an average high of 9.3 °C (49 °F) and average low of 2.5 °C (36.5 °F)6 and with January being the coldest month. Snowfall is a rare thing in Osaka. Spring in Osaka starts off mild, but ends up being hot and humid. It also tends to be Osaka’s wettest season, with the Tsuyu or rainy season occurring between late May and early July. Summers are very hot and humid. In the months of July and August, the average daily high temperature approaches 35 °C (95 °F), while average night time temperatures typically moves around 25 °C (77 °F). Fall in Osaka sees a cooling trend, with the early part of the season resembling summer while the latter part of fall resembles winter.7 The table below displays average monthly climate indicators in OSAKA based on 8 years of historical weather readings. Temperature is in Celsius and Precipitation is in mm8

Table 1: Average Climate Analysis in Osaka

Ja n

Fe b

Ma r

Ap r

Ma y

Ju n

Ju l

Au g

Se p

Oc t

No v

De c

5

5

9

15

20

23

27

28

25

19

13

8

Avg. Temperature

Max 9

9

13

19

24

27

31

33

28

23

17

12

Avg. Temperature

Min 2

1

5

10

15

19

24

25

21

15

9

4

Avg. Temperature

Avg. Rain Days

10

9

11

8

9

12

9

6

9

8

7

6

Avg. Snow Days

1

3

0

0

0

0

0

0

0

0

0

0

5

http://en.wikiarquitectura.com/index.php/Azuma_House accessed June21, 2013 (11:54) http://www.jma.go.jp/jma/indexe.html accessed June21, 2013 (15:47) 7 http://www.jma.go.jp/jma/indexe.html accessed June21, 2013 (15:47) 8 http://www.climate-zone.com/climate/japan/celsius/osaka.htm accessed June21, 2013 (15:47) 6

4

Figure 3: Different Views

1.2.

Building’s Detailed Description and Analysis

Azuma house is built on a plot of 57.3 m². The total floor area of 64.7 m² is divided into three equal sections: two floors and a patio yet the concrete box occupy the entire site. On the ground floor, we have living room, kitchen & bathroom separated by the central outside courtyard and the staircase that leads to the upper floor, where the two bedrooms are joined by a walkway. The central uncovered area is the only source of natural light throughout the house.9 On ground floor, courtyard separates the living room located at one end of the ground floor from the kitchen-dining room and bathroom on the other end. On the top floor, the children's rooms on one side face the master bedroom on the other side of the central courtyard, which is reached by a bridge. The building shows a blind or solid facade to the street10 Centralizing the building around courtyard makes it an integral part of circulation and the focus of everyday life and there is no way to cross to either side of the house without passing through open air courtyard. By this way, occupants experience the nature every single day even if they stay within the home all day11. The building envelope of the Azuma Row House is simple and uniform, a. Apart from its inward facing glass walls and minimal wood finish, the majority of the envelope is cast concrete, which has a very high specific heat capacity (0.880 J/(gK)), and therefore capable of absorbing a lot of heat energy. This trait affects the heating and cooling of the interior and courtyard in various ways.12 Constantly exposed to the sun, the concrete and stone slabs receive heat energy from the sun’s direct radiation, diffused sky radiation, and any rays reflected off of surrounding buildings. They cannot easily conduct or release this energy and stores it throughout the day, gradually increasing in temperature. The ground can retain a large amount of heat for hours, which can make standing in that space uncomfortable. Also since hot air molecules rise, the air will be overheated and uncomfortable as well. This is a greater concern in the summer time when exposure and temperatures are high. Furthermore, by placing the exterior space at the centre of the row house the building envelope’s surface area almost doubles, which can be a crucial matter for envelope dominated structures.13

9

http://en.wikiarquitectura.com/index.php/Azuma_House accessed June21, 2013 (11:54) http://en.wikiarquitectura.com/index.php/Azuma_House accessed June21, 2013 (11:54) 11 http://contrahabit.wordpress.com/2011/11/09/azuma-row-house-by-tadao-ando-designing-architecture-topurposefully-make-people-feel-uncomfortable/ accessed June21, 2013 (23:10) 12 http://contrahabit.wordpress.com/2011/11/09/azuma-row-house-by-tadao-ando-designing-architecture-topurposefully-make-people-feel-uncomfortable/ accessed June21, 2013 (23:10) 13 http://contrahabit.wordpress.com/2011/11/09/azuma-row-house-by-tadao-ando-designing-architecture-topurposefully-make-people-feel-uncomfortable/ accessed June21, 2013 (23:10) 10

5

1.3.

Thermal flow study of Azuma House

In each room there are four surfaces of exposed concrete. Although the floors on top floor are covered with wood slats providing insulation between the foot and slab, there is still conduction of heat energy through the walls. Moreover wooden tile’s floor luxury is only for top floor and ground floor is tiled with Black Slate tiles means considerable heat losses are through it. Bearing in mind the house’s small scale, there is likely considerable contact with the building envelope which prompts measurable heat loss from the human body which would be comfortable during warm seasons but frustrating during cold.14 The sixth surface of every room is a floor-to-ceiling plane of glass with a glass door. Although certain types of glass have relatively high heat capacities, the metal frame that support the panes are highly conductive which ensures presence of thermal bridges. A significant temperature difference across this barrier will cause a convection current that will easily circulate warm air into a cooler courtyard, and vice versa, causing fluctuations in the room’s temperature.15 Figure 4: Conduction and Convection of Azuma House

16

14

http://contrahabit.wordpress.com/2011/11/09/azuma-row-house-by-tadao-ando-designing-architecture-topurposefully-make-people-feel-uncomfortable/ accessed June21, 2013 (23:10) 15 http://contrahabit.wordpress.com/2011/11/09/azuma-row-house-by-tadao-ando-designing-architecture-topurposefully-make-people-feel-uncomfortable/ accessed June21, 2013 (23:10) 16 http://contrahabit.wordpress.com/2011/11/09/azuma-row-house-by-tadao-ando-designing-architecture-topurposefully-make-people-feel-uncomfortable/ accessed June21, 2013 (23:10)

6

2. Building Evaluation (w.r.t energy consumption and CO2 emission) – Before Rehabilitation

2.1. Building energy codes Japan has two building energy codes for residential buildings or houses (Table 1). The prescriptivebased Design and Construction Guidelines on the Rationalization of Energy Use for Houses (1999), or DCGREUH, includes insulation of the building envelope, HVAC, water heating, and the other one is The Criteria for Clients on the Rationalization of Energy Use for Houses (1999), or CCREUH, a mixture of performance and prescriptive-based building energy codes, has a heavy focus on HVAC. It also provides performance-based yearly heating and cooling loads by building type.17 From the Figure below we can see that Our Building which is located in Osaka belongs to Climate Zone IV, with the base Temperature of 18°C and the Heating Degree Days (HDD) is between 1,500 < HDD < 2,500. Figure 5: Residential Climate Zones in Japan

Table 2: Residential Climate Zone (Heating Degree Days)

18

In order to calculate the U-value of the building, there are some parameters that have to be used, including the R-value and Thermal Conductivity. Below is the list of different R-value of each part in the building, classified by the climate zone, range from zone I until zone V.

17

http://www.iea.org/efficiency/CD-EnergyEfficiencyPolicy2009/2-Buildings/2Building%20Codes%20for%20COP%202009.pdf (pg.7, date accessed 21.06.2013) 18

DCGREUH 1999

7

2.2 Parameters to calculate Building Energy Consumption There are different technical parameters that are needed to calculate the energy consumption, specifically the heating consumption, and here are the followings:



Thermal Conductivity (λ or k-value): In simple terms this is a measure of the capacity of a material to conduct heat through its mass. Different insulating materials and other types of material have specific thermal conductivity values that can be used to measure their insulating effectiveness.19



Thermal Conductance: the amount of heat (in kcal) conducted in one hour through 1 m2 of material, with a thickness of 1 m, when the temperature drop through the material under conditions of steady heat flow is 1 °C.20



Thermal resistance (R-value): The R-value can be defined in simple terms as the resistance that any specific material offers to the heat flow. A good insulation material will have a high R-value. Table 3: Minimum Heat Resistance (R-value) for Insulation Materials by Climate Zone

21



Coefficient of heat transmission (U-value): The symbol U designates the overall coefficient of heat transmission for any section of a material or a composite of materials. The U coefficient includes the thermal resistances of both surfaces of walls or flooring, as well as the thermal resistance of individual layers and air spaces that may be contained within the wall or flooring itself.22

19 20 21 22

http://www.fao.org/docrep/006/y5013e/y5013e08.htm accessed 25.06.2013 http://books.google.de/books?isbn=9251050104 accessed 25.06.2013 DCGREUH 1999

http://www.fao.org/docrep/006/y5013e/y5013e08.htm accessed 25.06.2013

8

Table 4: Energy efficiency requirements for heat transfer

23

Values for different parts are set in W per °C per sec. Different values are set for different types of constructions and for reinforced concrete structures, and other types of buildings.



Thermal Bridge: A thermal bridge (or cold bridge) is an area of the building fabric which has a higher thermal transmission than the surrounding parts of the fabric, resulting in a reduction in the overall thermal insulation of the structure. It occurs when materials that have a much higher thermal conductivity than the surrounding material (i.e. they are poorer thermal insulators) penetrate the thermal envelope or where there are discontinuities in the thermal envelope. Heat then flows through the path created – the path of least resistance – from the warm space (inside) to the cold space (outside).24 Thermal bridges occur due to: a. Geometrical effects, such as corners. b. Penetrations through the thermal envelope, for instance windows and doors. c. Junctions between different elements (wall and floor) and different components (around windows and doors). d. Poor construction practice (gaps or discontinuities in thermal insulation) (Leeds Metropolitan University & AECB).



23

Air Infiltration and Exfiltration: Infiltration is the uncontrolled passage of outdoor air into a building through unintended leaks in the building envelope (e.g., cracks between wall

DCGREUH 1999

24

http://www.leedsmet.ac.uk/teaching/vsite/low_carbon_housing/thermal_bridging/definitions/index.htm accessed 24.06.2013

9

sections, wall-floor connections, corners, the roof-wall interface, around windows and doors). Exfiltration is the opposite process.25

2.3 The Calculation Method: In the following section we will describe two methods of calculating the Building Energy consumptions. The first method will be based on the heating degree days, and the second method will be simulated by a building energy simulation software, which is developed by Graduate’s research of Massachusetts Institute of Technology, Boston, United States of America. First of all, there are several aspects that have to be included when we want to calculate the whole building energy consumption, and here are the ensuing aspects: a. Thermal characteristics of the building (shell and interior partitions, etc.) and these characteristics also include air-tightness b. heating installation and hot water supply, including their insulation characteristics c. ventilation d. air-conditioning installation e. built-in lighting installation (mainly the non-residential sector) f. position and orientation of buildings, including outdoor climate g. passive solar systems and solar protection h. natural ventilation i. Indoor climatic conditions, including the design indoor climate

2.3.1. Degree-day method

A degree-day method is basically the summary of the number of degrees that the average daily temperature (technically the average of the daily maximum and minimum) is above (for cooling) or below (for heating) a base temperature times the duration in days. Heating or cooling degree-day methods assume a fixed outside air temperature at which heating or cooling will begin to occur.26

Tbal = base temperature (or balance point temperature) (e.g. 18.3°C ) ; Q load = Q gain + Q loss = 0 T0= outdoor temperature (e.g. average daily max.min) *Degree-hours if we intend to summary over 24-hourly intervals, Degree-day =∑(degree-hours)/2427

25

http://www.upmchealthsecurity.org/website/resources/multimedia/2008protecting_building_occupants/images/infiltration.html accessed 24.06.2013 26 Anti Hamburg (TTK-UAS) - How to achieve low-energy building from old apartment building. Accessed 21.06.2013 27

http://www.chem1.com/acad/webtext/pre/enheat.html accessed 22.06.2013

10

2.3.2. Principle of the heating degree-day method: Heat losses for heat emission and control of the indoor temperature in a building depend on: • • • • •

the building energy need for space heating (building thermal properties and the indoor as well outdoor climate) non-uniform internal temperature distribution in each thermal zone (differences between air temperature and mean radiant temperature) Emitters embedded in the building structure towards the outside or unheated spaces control of the operative temperature (local, central, set-back , thermal mass, etc) auxiliary consumption28

The calculation of emission losses shall take into account: • energy interaction between type of emitters (radiator, convector, floor/wall/ceiling heating systems) and space • type of room/zone thermal control strategy and equipment (thermostatic valve, P, PI, PID control) and their capability to reduce the temperature variations and drift; • Position and characteristics of emitters. 29 Based on these data, the following output parameters for the heat emission sub-system, including control, shall be calculated: — total emission system heat losses; — Auxiliary energy consumption; 2.3.3. Heating degree days

Heating degree days are a measurement of how much (in degrees), and for how long (in days), the outside air temperature was below a certain level. They are commonly used in calculations relating to the energy consumption required to heat buildings. Basically, the analogy goes like this, the colder the outside air temperature, the more energy it takes to heat a building. The idea is that the amount of energy needed to heat a building is directly proportional to the number of heating degree days in that day/week/month/year.30 Using the heating-degree-days formula below, we get the total number of heating degree days in the region on which our building (Azuma House) is located.31

28

Anti Hamburg (TTK-UAS) - How to achieve low-energy building from old apartment building. http://iti.vgtu.lt/sure/Media/Default/Presentations/Anti%20Hamburg%209.04.2013.pdf Accessed 21.06.2013 29 Anti Hamburg (TTK-UAS) - How to achieve low-energy building from old apartment building. http://iti.vgtu.lt/sure/Media/Default/Presentations/Anti%20Hamburg%209.04.2013.pdf Accessed 21.06.2013 30 http://www.degreedays.net/introduction#Final_degree%282D%29day_advice (date accessed : 22.6.2013) 31 http://degreedays.net/47772 (date accessed:22.6.2013)

11

Table 5: Heating degree days in Sumiyoshi, Osaka, Japan

Months 15 6/1/2012 7/1/2012 8/1/2012 9/1/2012 10/1/2012 11/1/2012 12/1/2012 1/1/2013 2/1/2013 3/1/2013 4/1/2013 5/1/2013 Average Heating degree days

16 0 0 0 0 6 85 258 303 262 146 61 13 1134

17 0 0 0 0 10 110 289 334 290 171 80 18 1302

18 0 0 0 0 17 138 320 365 318 198 102 25 1483

19 0 0 0 0 27 166 351 396 346 227 126 34 1673

20 0 0 0 0 40 196 382 427 374 257 151 46 1873

21 3 0 0 1 56 226 413 458 402 287 177 60 2079

9 0 0 2 75 256 444 489 430 318 205 77 2294

1700.33333 Table 6: Heating energy consumption per year

Heated area Envelope Exterior wall Roof Floor

391 U W/m²*K 3.85 4.45 2.49

Thermal/Cold bridges Ventilation+ infiltration H3+H4

1.17

Free heat per 1 m² Utilisation Free heat for calculation per 1m² Whole building free heat The average free heat load temperature increase from the free heat Δtvs=Φvs/H Indoor temperature ts Balanced temperature tb=ts-Δtvs

m² A m² 294.90 31.02 64.70 H1 H2 0.0 Σ

14.0 50.00 7.00 2737 4.18 7.04

kWh/m²a % kWh/m²a kWh/a kW °C

25.00 17.96

°C °C

H1 W/K 1135 138 161 1435 1173 1416 4.02

12

2.3.4. Calculation of U values The U-value is calculated by following five steps.32 1. 2. 3. 4.

Calculate Upper resistance limit(Ri) Calculate Lower resistance limit (Re) Calculate Total thermal resistance (RT) =Ri + Re Calculate corrections / adjustments for a) Air gaps penetrating the insulation (ΔUg) b) Mechanical fixings penetrating the insulation (ΔUf) U = ( 1 / RT ) + ΔUg + ΔUf Note: ΔUg and ΔUf can be omitted, if taken together, if they amount to less than 3% of the U-value found from U =1 / RT Table 7: Calculation of u-value for External walls

External wall Materials Ri Concrete Concrete Re

Thickness M

λ W/m·K

0.02

1.700

0.05 0.07 Total R= U=

1.700 0.26 3.85

R m²·K/W 0.15 0.02 0.05 0.04 m²·K/W W/m²·K

Table 8: Calculation of u-value for Floors

Floor Materials

Thickness (m)

λ (W/m·K)

M

W/m·K

0.1

1.630

0.06

0.001 0.101 R= Uf=

2.000

0.00 0.17 m²·K/W W/m²·K

Ri Concrete

Re

32

0.40 2.49

R (m²·K/W) m²·K/W 0.17

http://www.iso.org accessed 22.06.2013

13

Table 9: Calculation of u-values for roof

Roof Materials Ri Concrete Concrete Re

Thickness M

λ W/m·K

0.08

1.630

0.05

1.630

0.03 0.04

R= U=

0.22 4.45

m²·K/W W/m²·K

R m²·K/W 0.1 0.05

2.3.5. Formula to calculate of the Heat Losses Heat losses H 1 = ΣU i⋅ A i33 U i– Envelope thermal conductivity, W/m2⋅K A i – Envelope area, m2 H 2 =ΣΨi ⋅ li ΣΨi – thermal bridge conductivity, W/m⋅K li – thermal bridge length, m H 3= Vinf ⋅ c ⋅ρ qi – air change, m3/s H 4= ΣL ⋅ c ⋅ρ ⋅ (1- f) ΣL – Air change, m3/s C – Air specific heat, 1005 J/kg⋅ K ρ – Air density, 1, 2 kg/m3 f – Heat recovery efficiency (0, 6 or 0, 7)

2.3.6. Formula to calculate of the Heating energy consumption Ф HL = H⋅S⋅24⋅10-334 Ф HL – Heating energy usage, kWh/a H – Building specific heat conductivity, W/K S – Degree-days, °C⋅ d 24– Day, h Фnet - Net energy need kWh/m2*a H= H 1+ H 2+ H 3+ H 4 (W/K) H 1 – Building envelopes specific heat conductivity 33

http://iti.vgtu.lt/sure/Media/Default/Presentations/Anti%20Hamburg%209.04.2013.pdf p.14,accessed 22.06.2013 34 http://iti.vgtu.lt/sure/Media/Default/Presentations/Anti%20Hamburg%209.04.2013.pdf p.15,accessed 22.06.2013

14

H 2 – Building cold bridges specific heat conductivity H 3 – Infiltration specific heat conductivity H 4 – Ventilation specific heat conductivity

Table 10: yearly heating energy per heated area

Envelope

Area m

Exterior wall Roof Floor Door Thermal/Cold bridges

202 31.02 64.70 1.60

2

degreedays tb=

1700.333

U-value, W/(m2K) 3.85 4.45 2.49 4.65

Heat losses kWh

17.96

34672 4215 274 227 27925 Heat losses (kWh)

Yearly Heating energy per heated area

Σ kWh/m2

67315 172.2

2.4. Building simulation method for calculating the energy consumption The building simulation is intended to help the Building designers, architects, as well as engineers for the comparison of the estimated saving energy. The aim is to make a building simulation tools that is easily applied by relevant sectors respectively, and to combat the excessive complexity of many building energy simulation software, that unfortunately not accessible to the dependable sectors.

2.4.1. MIT Design Advisor

The MIT Design Advisor is a building simulation tool for estimating the heating, cooling, and lighting energy demand of an early-stage building design. Using basic inputs about a building, the MIT Design Advisor can quickly simulate required heating, cooling, and lighting energy needs; predict thermal comfort; and provide useful design information. The building geometry, operating conditions, material properties, and local climate data are used to determine the building's behaviour throughout the year.

15

Figure 6: screenshot of MIT design software

Below are a list of the simplifying assumptions and calculation procedures that are made in the simulation process.

2.4.2. Weather Data Climate data for the selected city is used to perform detailed heat and mass transfer calculations for each hour of the year. The hourly climate data that this model uses includes:  Outdoor Air Temperature (dry bulb)  Outdoor Air Humidity (relative humidity)  Incoming Solar Radiation (direct and diffuse)  Incoming Solar IL luminance (direct and diffuse)  Wind speed and direction (used only for natural ventilation) The weather data on this site has been generated by the METEONORM software package (v.4.0).35

2.4.3. Calculations Each hour of the year, a heat and mass transfer analysis is performed on the building. Air temperature and humidity, and indoor lighting levels are calculated as they vary throughout the hour, day, month, and year. As changes occur to the building environment, the building's systems respond to provide adequate levels of air temperature, humidity, and light: Heating loads occur when the air temperature drops below a user-specified temperature. 35

http://www.meteonorm.com/ (date accessed 23.06.2013)

16

  

Cooling loads occur when the air temperature or humidity increase above user-specified limits. Lighting loads depend on the minimum lighting requirement and the amount of available daylight. Heating, cooling, and lighting systems each use energy to maintain comfortable indoor conditions. Several ventilation strategies can be simulated, and each affects the way that loads are calculated. Assumptions are all described in the sections below.36

2.4.3. Ventilation Ventilation is required to bring fresh air into the building. The user must specify the minimum ventilation in air changes per hour. One air change is equivalent to replacing the entire volume of air in the building with the same volume of fresh air. Air changes can be specified directly, or the air change rate can be linked to the typical number of people in a room. Different values can be specified for times when the building is occupied vs. unoccupied.37 Fresh air is usually introduced into a building in three ways: 1. Mechanical systems (intake and/or exhaust fans) 2. Natural ventilation (opening windows) 3. Infiltration (leaks around windows & doors) And therefore, all three cases share the following assumptions:  Fresh air is brought into the building at the outdoor air temperature.  Indoor air is exhausted from the building at the indoor air temperature.  No energy is recovered from the exhaust air. 38  Fan energy is not considered.

2.4.4. Cooling Loads When the indoor air temperature climbs above the high temperature set point, a cooling load is required. Similarly, when the indoor air relative humidity climbs above the maximum-humidity set point, a (latent) cooling load is required. If Natural Ventilation Cooling is chosen, then no chiller system is available and the cooling load is reported as zero. The air temperature will float freely above the minimum temperature. In this case the user can view a histogram of the hours spent at a given air temperature to determine how often the building would be uncomfortably hot without using a mechanical chiller.39 Factors that contribute to the cooling load include: • Solar gains: direct and diffuse radiation passing through window/blind system. • Heat passing through the building envelope (walls, roof, and windows). • Heat from electric lights. • Heat from equipment. • Heat from occupants: 75Watts/person (sensible) + 55Watts/person (latent). • Ventilation and infiltration (air flows): Mass Flow x Cp x (T_inside – T_outside).40

36

http://designadvisor.mit.edu/design/assumptions.html#heating (date accessed 23.06.2013) http://designadvisor.mit.edu/design/assumptions.html#ventilation (date accessed 23.06.2013) 38 http://designadvisor.mit.edu/design/assumptions.html#ventilation (date accessed 23.06.2013) 39 http://designadvisor.mit.edu/design/assumptions.html#cooling (date accessed 23.06.2013) 40 http://designadvisor.mit.edu/design/assumptions.html#cooling_loads (date accessed 23.06.2013) 37

17

2.4.5. Heating Loads When the indoor air temperature falls below the low temperature set point, a (sensible) heating load is required. Factors that contribute to the heating load include: • Solar gains: direct and diffuse radiation passing through window/blind system. • Heat passing through the building envelope (walls, roof, and windows). • Heat from electric lights. • Heat from equipment. • Heat from occupants: 75Watts/person (sensible) + 55Watts/person (latent). • Ventilation and infiltration (air flows): Mass Flow x Cp x (T_inside – T_outside).41

2.4.6. Building Envelope The building envelope includes all exterior building surfaces - walls, doors, roofs - through which heat and light may be exchanged with the outdoor environment. To simplify the simulation, the contributions of the ground to the energy balance have been neglected. Modelling assumptions for the envelope are as follows:

2.4.6.1. Roof General Roof Model Assumptions:  Roof construction consists of a 15 cm concrete roof slab with insulation installed as specified by user.  The convective transfer coefficient between the roof surface and outdoor air is taken to be 10 W/m²-K.  The infrared radiation heat transfer coefficient between the roof surface and the sky temperature, which is assumed to be 10 K lower than the outdoor temperature, is 6 W/m²-K.  Concrete for roof slab has a Cp = 880 J/kg-K, a density = 2400 kg/m³, and conductivity = 1.4 W/m-K.  The overall heat transfer coefficient between the bottom of the roof slab, or ceiling, and room is taken to be 10 W/m²-K. This value accounts for convection and radiation.  The energy consumption of the top floor (which has the roof above) is averaged with the energy consumption of the interior floors (which have adiabatic ceilings), to reach an overall building average.42 2.4.7. Energy Balance An energy balance is carried out each hour using weather data for the selected city. The air in a room is assumed to be well-mixed at a uniform temperature. • The balance includes heat transfer between the air and thermal mass. • The thermal mass temperature is calculated by dividing it up into 10 equal-thickness layers and doing a heat balance for each layer. • For heavy thermal mass the floor area is assumed to be 20 cm thick concrete with a bare surface. • Concrete for thermal mass has a Cp = 880 J/kg-K and a density = 2400 kg/m³ • The heat transfer coefficient between the floor surface and air is taken to be 8 W/m²-K. 41 42

http://designadvisor.mit.edu/design/assumptions.html#heating_loads (date accessed 23.06.2013) http://designadvisor.mit.edu/design/assumptions.html#roof (date accessed 23.06.2013)

18

2.4.8. Building Information 43

Table 11 Building parameters for Azuma house Building Location Japan – Osaka Building length, side A 14.1 m Building length, side B 3.3 m Simulation Type Simulation Type four_sided_facade Window Description Window Area 0% Wall Description 2 Insulation R-Value 0.26 m -K/W Occupancy Type Low-rise Residential 2 Occupancy Load 0.050 people per m Lighting Requirements 300 lux 2 Equipment Load 5.00 W/m Room Ventilation Air Change Rate per 15.0 liters / sec per person Occupant Total Air Change Rate 1.0 roomfuls per hour Lighting Control Lighting Control lights respond to sunlight: all lights controlled by a single dimming switch Representative Room Orientation North Room Depth 4.7 m Room Width 3.3 m Room Height 2.7 m Thermal Mass Thermal Mass High Overhang Overhang Depth 0m Roof Roof Type Conventional roof 2 Roof Insulation R-Value 0.22 m -K/W Number of Floors 2 floor(s)

2.4.9. Simulation Results Table 12: Primary energy Use and Co2 emissions heating cooling lighting total CO energy energy energy energy emissions (kWh/m ) (kWh/m ) (kWh/m ) (kWh/m )

(kg/m )

January

36.4

0.0

4.1

40.5

8.1

February

32.4

0.0

3.7

36.1

7.2

March

29.2

0.0

4.1

33.3

6.7

April

16.2

0.0

4.0

20.2

4.0

May

6.7

0.2

4.1

11.0

2.2

June

2.4

0.9

4.0

7.3

1.5

43

MIT design advisor http://designadvisor.mit.edu/design/

19

July

0.0

6.2

4.1

10.3

2.1

August

0.5

12.4

4.1

17.0

3.4

September

1.0

3.9

4.0

8.9

1.8

October

8.8

0.0

4.1

12.9

2.6

November

19.4

0.0

4.0

23.4

4.7

December

30.7

0.0

4.1

34.8

7.0

183.7

23.6

48.4

255.7

51.1

Total

Figure 1 yearly Building energy consumption

RED Heating energy required per square meter of plan. BLUE Cooling energy required per square meter of plan. GREEN Lighting energy required per square meter of plan. GRAY Total energy required per square meter of plan. Primary Energy Use, which is the amount of energy contained in the raw fuels (coal, natural gas, nuclear fuel, etc.) that are used to generate the electricity or heat used by the building.

PRIMARY HEATING ENERGY PRIMARY COOLING ENERGY PRIMARY LIGHTING ENERGY

= Heating Load / Thermal Efficiency = Cooling Load / (Electricity Production Efficiency x Chiller Coefficient of Performance) = Lighting Load / (Electricity Production Efficiency x Lighting Efficiency)

Figure 2: monthly Building energy consumption

20

2.4.10. Energy

Energy requirements are computed for the entire building and normalized to a per-floor-area basis. Heating, cooling, and lighting loads are displayed independently on a yearly or monthly basis. The displayed energy values reflect the primary or formal fuel requirements of the building - this energy amount corresponds to the energy content of the fossil fuel (primary energy) that needs to be burned to maintain the specified building conditions.44 2.4.11. Life cycle Cost

By specifying the unit cost of heating and electricity, years of operation, and an appropriate yearly discount rate (to account for the time value of money), we can estimate the energy cost of the proposed building. Typical costs for heating and electricity are given, but these can be varied to suit the conditions. All costs must be entered in the same monetary units (for example, dollars per dollars per kW-hr). The bars represent the cost of heating (red), cooling (blue), and lighting (green) all normalized on a per-floor-area basis. The sum of heating, cooling, and lighting energies is displayed below the graph ($/sq. meter).45 The energy models have undergone careful scrutiny to ensure accuracy although the MIT Design Advisor model shows good agreement; it is worth noting that this tool is meant only to estimate energy demand and building performance. Since building designs undergo many changes between the conceptual stage and the finished product, it is unreasonable to expect accuracy that is better than 10% of the final design. The focus is to show the relative impact of the most significant design choices on the overall building performance, and accuracy is sufficient for this purpose.46

44

http://designadvisor.mit.edu/design/assumptions.html#energyhelp accessed 23.06.2013 http://designadvisor.mit.edu/design/assumptions.html#lifecyclecost accessed 23.06.2013 46 http://designadvisor.mit.edu/design/assumptions.html accessed 23.06.2013 45

21

3. REHABILITATION MEASURES AND RECOMMENDATIONS 3.1. Thermal Insulation A heat transfer is the movement of heat from the space with higher temperature to the space with lower temperature. The techniques and methods which are exploited so as to control and decrease the rate of this transfer are known as the Thermal Insulation. This type of insulation has pursued the goal of minimizing the energy wastage in a building in order to maximize the energy efficiency47. The main reasons for using the Thermal Insulation are:



The most important target which is followed by using the thermal insulation is the reduction in the rate of energy consumption. Various researches have confirmed that the appropriate thermal insulation can effect extensively on the rate of electricity usage as it is able to diminish this rate up to 50%.



Thermal insulation can decrease the dependency of the users upon the air conditioners and heating systems.



Thermal insulation protects building components by limiting the temperature difference in various components, the difference which is caused by different temperatures in different period of a day48.

3.2. Insulation Target The important subject about the thermal insulation is the target which is followed in order to achieve the best level of energy efficiency. The below table depicts the target U-value of every building element and the possible solution which can be observed so as to reduce the energy wastage. In the following, these solutions will describe deeply to find the most effective methods for thermal rehabilitation of the Azuma House.

Building Elements

Target U-value

Possible Solution

Walls Windows and Doors

0.15 1.6

Roof

0.10

Floor Gaps, Tracks, Draughts

0.15 N/A

Cavity, internal or external wall insulation Double/triple/secondary glazing / shutters and curtains Pitched, warm deck or cold deck roof insulation Floor insulation Draught-proofing / ventilation with heat recovery Table 23: Insulation Target

49

47

https://sites.google.com/site/thermalisulation/thermal-isulation-and-its-principles/what-is-thermalisulation-what-are-principles-of-this, Date accessed: 25.06.2013 48 http://dce-ksa.com/thermal.html, Date accessed: 25.06.2013

22

3.3. Wall Insulation There are two main wall types, namely, Cavity and Solid Walls. There are, of course, other types of walls which are not classified in these two types, for instance, steel-frame walls, wood-frame walls, prefabricated concrete walls. Due to lack of gap, these walls can be considered as the solid walls regarding the thermal insulation50. 3.3.1. Cavity Wall Insulation Cavity wall insulation (CWI) is the type of insulation which is located in the central gap between external and internal wall layers. In the case of rehabilitation, this insulation is injected into this gap and fills this space which generally is not occupied by any materials. This process is performed by using the holes which are made on the external wall layer51.

Figure 20: Cavity Wall Insulation

52

3.3.2. Solid Wall Insulation Although heat transfer from the solid walls is more than the cavity walls, there are two options regarding this type of wall. Solid walls can be insulated from two sides, namely, inside and outside53. Generally, the solid wall insulation is classified into two types of Internal Wall Insulation (IWI) and External Wall Insulation (EWI). It should also be noted that these two types can be combined in the process of construction and/or rehabilitation. As Azuma house has solid walls, so we will discuss only solid wall insulation. 3.3.2.1. External Wall Insulation External wall insulation is the employment of an insulation layer on the outer surface of the buildings’ walls, the layer which is covered by the specific materials in order to protect from it. 49

http://www.superhomes.org.uk/resources/whats-best-insulation-material/, Date accessed: 26.06.2013 http://www.greenenergysavingtips.com/energy-saving-tips-house-energy-efficiency-wall-insulation/, Date accessed: 26.06.2013 51 http://www.homeenergysavingtips.co.uk/insulation.php, Date accessed: 26.06.2013 52 http://www.superhomes.org.uk/resources/interstitial-condensation-3/, Date accessed: 26.06.2013 53 http://www.greendealinitiative.co.uk/green-deal-products-2/solid-wall-insulation/, Date accessed:26.06.2013 50

23

Therefore, the constitutive elements of the external wall insulation are the insulation layer and the waterproofing cover. The material which is exploited for waterproofing cover is mostly the kinds of the render, although, other materials such as tiles, decorative boards, and so forth also can be employed54. This method of insulation is not appropriate for historic buildings or the buildings with specific decoration in their façade.

Figure 21: Solid Wall, External Wall Insulation

55

The below table depicts the pros and cons of the external wall insulation (EWI):

External Wall Insulation

Pros

Cons

a. Suitable insulation in order to reach to the minimum standards of insulation. b. Does not reduce the interior space. c. Does not need to change the position of electrical fixtures, pipes, and so on. d. Does not influence on the interior decoration. e. The minimum rate of disturbance for building’s users. a. Many experiences prove that the amount of insulation for external insulation is usually more than the internal one. Furthermore, the external wall insulation needs the waterproofing cover. b. External wall insulation is not a good solution for removing the cracks, draughts, and gaps in the building. c. It can create the technical problems that solving them is not possible. d. This process needs some kinds of permits. e. This insulation modifies the façade extensively. f. It is not an appropriate alternative for historic buildings. g. Partly expensive. Table 14: Pros and Cons of External Wall Insulation

54 55

56

http://www.facadeexternalsolutions.com/, Date accessed: 26.05.2013 http://www.superhomes.org.uk/resources/interstitial-condensation-3/, Date accessed: 26.05.2013

24

3.3.2.2. Internal Wall Insulation Internal Wall Insulation (IWI) is the layer of insulation which is installed on the inner surface of the exterior walls by exploiting some chemical and mechanical materials. The installation process is variable depends on the materials which are employed for insulation and the insulation layer should be covered with decorative plasterboard. This kind of insulation promotes the level of energy efficiency57.

Figure 22: Solid Wall, Internal Wall Insulation

58

The below table depicts the pros and cons of the Interior wall insulation (IWI):

Internal Wall Insulation

Pros

a. b. c. d. e.

Cons

a. b. c. d. e.

Suitable insulation in order to reach to the minimum standards of insulation. Suitable insulation for all kinds of walls. Suitable insulation for removing cracks, gaps, and draughts. Many experiences prove that internal wall insulation will not make many problems after installation. This insulation is the best alternative to be used as the supplementary insulation in the cavity walls in order to control the level of damp. The installation process makes some disturbances for the building’s users. Partly expensive. This insulation decreases the interior space of the building. To install this insulation, it is necessary to make changes in the inner space. To install this insulation, it is necessary to make changes in the interior decoration. Table 15: Pros and Cons of Internal Wall Insulation

59

56

http://www.sureinsulation.co.uk/downloads/Briefing_Paper_Wall_and_insulation_types.pdf, Date accessed: 26.06.2013 57 http://bob.instituteforsustainability.org.uk/knowledgebank/retrofitguides/guide-6/Pages/6.10--Internalwall-insulation-.aspx, Date accessed: 26.06.2013 58 http://www.superhomes.org.uk/resources/interstitial-condensation-3/, Date accessed: 26.06.2013

25

3.3.3. Comparison of Different Wall Insulation All types of wall insulation have specified disadvantages and advantages. Many factors can effect on the selection of the insulation type, namely, current situation, insulation needs, cost, technical restriction, and so forth. The below table compares the internal wall insulations and external wall insulation:

Excellent=9 Poor=1

Internal Wall Insulation

Effectiveness Cost Disruption Success Rate Addresses Draughts/Airtightness Suitable for Individual House

9 2 1 9 9 9

Suitable for All House Types

9

External Wall Insulation

Table 16: Comparison of Internal and External Wall Insulation

7 1 5 8 2 1 1 60

3.4. Roof Insulation In general, there are two types of roof, namely, the pitched roof and the flat roof. The insulation of these two types can be classified into cold and warm roofs based on the place of insulation. On the other hand, there are two other types of insulation which are called the cool roof and green roof. In the following, the cool roof, green roof as well as the flat roof insulation will be described so as to become acquainted with the pros and cons of these types of insulation. 3.4.1. Flat Roof A roof with a slope of less than 10 degrees is determined as the flat roof. The place of the insulation layer specifies that the building has the warm roof and/or cold roof 61.Therefore; generally, there are two methods for roof insulation considering the position of the insulation. 3.4.1.1. The Cold Roof The cold roofs are the roofs that have insulation between their roofs joists located beneath the structural deck. The advantage of this kind of insulation is that it does not carry any kinds of loads and it does not need any extra vapour control layer. However, the drawback is that it is necessary to have ventilation over the insulation layer in order to avoid the moisture vapour62.

59

http://www.sureinsulation.co.uk/downloads/Briefing_Paper_Wall_and_insulation_types.pdf, Date accessed: 26.06.2013 60 Ibid, 26.06.2013 61 http://www.buildingregs4plans.co.uk/guidance_flat_roof_types.php, Date accessed: 24.06.2013 62 Ibid, Date accessed: 26.06.2013

26

Figure 23: The Cold Roof

63

3.4.1.2. Warm Deck Roof The warm deck roof is the roof in which insulation layer is located on the structural deck. Unlike the cold roof, the warm deck roof does not need the ventilation and it can protect from the outer layer of the roof. Another advantage of this kind of roof insulation is that it can prevent from high temperature differences in the roofs’ materials, the subject that causes to postpone the damage of

the material. Also, this type of roof insulation has the potential to control the condensation64. There are two types of warm deck roof. These two types are:



Sandwich Warm Deck Roof Most common roof insulation is the sandwich warm deck roof. In this method, the insulation is located beneath the waterproof layer and by employing the some chemical materials; this insulation is fixed above the roof65.

Figure 24: Sandwich Warm Deck Roof



66

Inverted Warm Deck Roof In this method, the position of the waterproofing layer is different from the sandwich roof. In the inverted warm deck roof, the insulation layer is located above the waterproof layer and insulation layer is covered by the layer of ballast. The water proof can have the other layer for protecting the insulation layer from the extra load67.

63

http://www.greenspec.co.uk/timber-flat-roof-insulation.php, Date accessed: 26.06.2013 http://www.buildingregs4plans.co.uk/guidance_flat_roof_types.php, Date accessed: 26.06.2013 65 Ibid, 26.06.2013 66 http://www.greenspec.co.uk/timber-flat-roof-insulation.php, Date accessed: 26.06.2013 67 http://www.buildingregs4plans.co.uk/guidance_flat_roof_types.php, Date accessed: 26.06.2013 64

27

Figure 24: Inverted Warm Deck Roof

68

3.5. Floor Insulation Floor insulation is the process of adding the insulation layer under the floorboards. This type of insulation assists to control the heat transfers from the floor and ground. Furthermore, this insulation promotes the level of draught proofing by covering the draughts through the floorboards and skirting boards69. 3.5.1. Floor Insulation Methods These are four methods for concrete floor insulation regarding to the process of rehabilitation. 3.5.1.1. Upgrading an Existing Slab The easiest method for improving the level of floor insulation in existing floor is appending the insulation layer above the existing floor, the insulation which is covered by the new deck. Although, this method is easy, it makes some serious problems associated with the fixed furniture in the home because the height of the floor will increase after performing this kind of insulation70.

Figure 25: Upgrading an Existing Slab

71

The below table shows the advantage and disadvantage of this method:

68

http://www.greenspec.co.uk/timber-flat-roof-insulation.php, Date accessed: 26.06.2013 http://www.thegreenage.co.uk/tech/floor-insulation/, date accessed; 26.06.2013 70 http://www.greenspec.co.uk/ground-floor-insulation.php, Date accessed: 26.06.2013 71 Ibid, Date accessed: 26.06.2013 69

28

Upgrading an Existing Slab Advantage

The simplest method for promoting the level of floor insulation

Disadvantage

Can create the serious problems about the fixed furniture of the building.

Table 13: Advantages and Disadvantages of Upgrading an Existing Slab

72

3.5.1.2. New Slab – Insulation above Slab This is another alternative for improving the level of floor insulation. In this method, a layer of screed or board is joined above the insulation layer, the layer which is located on the new slab. The screed and board have some advantages and disadvantages. The screed is better in the thermal insulation process rather than the board. On the other hand, the installation of the board is quicker rather than the screed. In this system, it is able to insulate the gap between

the screed and board and walls as to decrease the thermal bridging. Also, in this system by using the sealant, it is able to control the air leakage73.

Figure 26: New Slab – Insulation above Slab

74

The below table shows the advantages and disadvantages of this method:

New Slab – Insulation above Slab

Advantages

1. The time for heating the building becomes shorter comparing the other kinds of floor insulation. 2. The place of insulation can be exploited for under floor heating systems.

72

Ibid, Date accessed: 26.06.2013 Ibid, Date Accessed: 26.06.2013 74 http://www.greenspec.co.uk/ground-floor-insulation.php, Date accessed: 26.06.2013 73

29

Disadvantages

1. From the technical view, it is important to consider the loads which must be borne by the insulation layer. 2. In the wet space such as bathrooms and toilets, this kind of insulation is not suitable.

Table 14: Advantages and Disadvantages of New Slab - Insulation above Slab

75

3.5.1.3. New Slab – Insulation below Slab This is another system in order to improve the thermal insulation of the floor. Unlike the previous system, in this system, the insulation layer is located beneath the new slab and there is no screed or board. Like as the previous system, this system can assist to reduce the thermal

bridging by filling the gap between the new slab and the walls. The mechanism of the controlling the air leakage is the same as the previous system76.

Figure 27: New Slab - Insulation below Slab

77

The below table shows the advantages and disadvantages of this method:

New Slab – Insulation below Slab

Advantages

1. It is possible to use the insulation layer with the less thickness than the above slab. 2. It has the better situation about the load spreading rather than the above slab.

75

Ibid, 26.06.2013 Ibid, 26.06.2013 77 http://www.greenspec.co.uk/ground-floor-insulation.php, Date accessed: 26.06.2013 76

30

Disadvantages

The quickness of heating in this system is less than above slab system.

Table 15: Advantages and Disadvantages of the New Slab - Insulation below Slab

78

3.5.1.4. Suspended Timber Floor Suspended timber floor is the floor which is installed above the floor with known distance from it. In other words, there is gap between the existing floor and the one which is installed as the new floor. The insulation layer is located between the joists of the floor so as to decrease the rate of heat loss. The main problem about this floor is the air leakage. It is necessary to consider this subject and solve this problem by employing the sealant in the suitable position. Insulation layer must cover all edges of the floor and the place close to the floor installation place. Also,

like as other insulation system, it is important that insulation covers the skirting gaps and draughts. The ventilation below the floor deck is another problem that can lead to reduce the efficiency of the insulation layer79.

Figure 28: Suspended Timber Floor

80

The below table shows the advantages and disadvantages of this method:

Suspended Timber Floor

Advantages

1. The insulation layer assists to minimize the time which is needed for heating 2. From technical view, the extra load must be born by the lateral components is in minimum state.

78

Ibid, Date accessed: 26.06.2013 http://www.greenspec.co.uk/ground-floor-insulation.php, Date accessed: 26.06.2013 80 Ibid, Date accessed: 26.06.2013 79

31

Disadvantages

1. There is no thermal mass about this system 2. There is serious problem about air leakage 3. Ventilation below the floor decreases the efficiency of the insulation layer Table 6: Advantages and Disadvantages of Suspended Timber Floor

3.6.

81

Draught Proofing

Draught proofing is the kind of insulation that assists to control the movement of air from warm to cold space. The draughts, gaps, and cracks in the building work like as the ventilation and waste the energy which is used in order to heat or cool the space. Draught proofing is the set of techniques

which are employed to fill the gaps, draughts, and cracks in the building so as to reduce the energy consumption82. Draught proofing can be considered about the windows, doors leading outside, inside doors, floors, entry lofts, loft rooms, chimneys and fireplaces, pipes, disused air conditioning vents and extractor fans, and cracks in walls. Draught proofing helps to reduce the uncontrolled infiltration, the subject that causes to reduce the heat loss83.

3.7.

Selection Criteria for Insulation Material

Insulation materials must be sustainable, resistant, durable, cost effective and require minimum maintenance. Also, it is necessary that this material have a suitable covers when they are employed at the outer space. Furthermore, it is necessary that these materials are protected from fire risk. Insulation materials can be classified into two categories of Organic and Non-organic materials. In addition, the organic materials are also categorized in Natural and Synthetic materials. This classification is founded based on the raw materials which are used in them84. The below table depicts some insulation material with related k-value based on the above classification and the place which these materials are used. Insulating Material Organic

K-value

Usage Place

Notes

Natural

Wood fiber batts Cellulose (loose, batt or board)

0.038 – 0.043 0.038 – 0.040

Roofs, Walls, Ceilings Horizontal surfaces

Flax batts, slabs and rolls

Approximately 0.042 0.042 – 0.050

Roof ,Wall, Floor

Hard to obtain and expensive

Commonly used as underlay under hardwood and ceramic floors. Horizontal Surfaces

Made by Sand, Cement, and

Cork board

Fiber Cement Gladding

0.24

Recyclable, renewable, made from finely shredded newspaper, easy to install

81

Ibid, Date accessed: 26.06.2013 http://www.thegreenage.co.uk/tech/draught-proofing/, Date accessed: 26.06.2013 83 Ibid, Date accessed: 26.06.2013 84 http://nesa1.uni-siegen.de/wwwextern/idea/keytopic/6.htm, Date accessed: 26.06.2013 82

32

Cellulose Synthetic Phenolic foam board

0.020 – 0.25

Expanded polystyrene board and beads (EPS) Eco-wool

0.032 – 0.040

For roofing, cavity board, external wall board and others Masonry cavities

0.039 – 0.042

Loft and stud walls

0.013 0.033 – 0.040

Skylights, Windows, Wall, Roof, Floor

0.033 – 0.040

Loft and cavity wall insulation Floor, Wall Roof, Floor Wall, Roof

Made from 85 percent recycled plastic. Comes in rolls or slabs.

Non-organic Aerogel Fiberglass mineral wool batts and Rolls Mineral (rock & slag) wool batts and roils Foamed glass slab Perlite Multi-foil insulation

0.042 0.045 – 0.05 disputed

Table 7: Insulation Material

3.8.

85

Recommendations System Recommendation and Insulation Material Used

Wall Insulation

1. Internal Wall Insulation (Rockwool boards) 2. External Wall Insulation (Fiber Cement Cladding)

Roof Insulation

1. Sandwich Warm Deck Roof (Wood fiber batts & Monrock/Phenolic foam board)

Floor Insulation

1. Upgrading an Existing Slab (Cork board)

Draught Proofing

1. Internal Wall Insulation (Same as above) 2. Upgrading an Existing Slab (Same as above) 3. Roof Insulation (Same as above)

85

http://www.superhomes.org.uk/resources/whats-best-insulation-material/, Date accessed: 26.06.2013

33

3.9.

Solar Shading Systems

There are two kinds of solar shading systems. External solar shading reduces cooling system necessity and controls heat gain. When g-value has a lower figure, it means minor amount of sunlight is absorbed. External window shadings block sunlight gain within 70%-85%. Some solar shading is not flexible. It means when climate changes, they can’t adapt themselves with new condition. Meanwhile, adjustable shadings have intelligent systems which make modifications any time.86 The angel of solar shading changes in different daytime to obtain suitable thermal comfort.87 Solar shading systems can be categorized regarding their placement; external, inter pane and internal. External ones are situated on the outer surface of openings, inter pane are positioned between panes and internal are located in the interior space. External shading systems are considered best solution as sunlight is sent back prior to cross windows. They absorb some amount of heat which distributes it to the environment through convection and radiation. However, external shadings require more maintenance costs as they encounter variety of climate conditions. Internal shadings radiate heat to interior space and as a result can avoid lower amount of heat gain.88

Figure 29: Exterior vs. interior solar shading

86 87

89

http://www.es-so.com/documents/windowprotection.pdf, Date accessed 22.06.2013

http://mesteksa.com/fileuploads/Literature/PartnerAccounts/1614/ColtSolarShadingLouverSystemsBrochure.p df Date accessed 20.06.2013 88 https://dspace.ist.utl.pt/bitstream/2295/143446/1/dissertacao.pdf Date accessed 25.06.2013 89

http://webcache.googleusercontent.com/search?q=cache:1IdAcUH10gEJ:www.buildup.eu/system/ files/content/REHVA-Journal-Sep08OriginalDPD.pdf+solar+shading+types+pdf&cd=6&hl=de&ct=clnk&gl=de Date accessed 20.06.2013 34

3.9.1. Venetian Blinds “External Venetian blinds, is the curtain of horizontal slats that can be tilted, raised and lowered.” Slats harmonize themselves with different sun orientation in order to benefit natural sunlight and thermal comfort. This type of solar shading system has benefit to be used in any climate circumstances. Slats reflect and absorb heat which leads to passive cooling system. In cold climate, closed blinds can reduce heat transition which shows strength of U-values.90 In order to save blinds from strong winds, some sensors distinguish the situation and command to tilt blinds at 90 degree.91

Venetian Blinds

Pros

Cons

a. Reduced total energy costs. b. Reduced air-conditioning demand. c. Decreased demand for artificial lighting by automatic slat adjustments. d. Control solar shading at different sunlight angles.92 93 e. Available in different materials for different circumstances. h. Precise calculation is needed to predict suitable function. i. Not enough regulations about solar shading systems. j. Mostly, shading is not taken into consideration because of poor data. k. Automated system may not always provide thermal comfort for occupants. l. In high-rise buildings automated systems are costly.94

Table 22: Venetian blinds Pro's and Con's

90

http://www.es-so.com/documents/KC2-Productsheets_Mai2010_ESSOE.pdf Date accessed 22.06.2013 http://www.horiso.com.au/SiteFiles/horisocomau/Brochure_Specialty_Venetian_Blinds_Horiso_2012.pdf Date accessed 26.06.2013 92 http://www.horiso.com.au/SiteFiles/horisocomau/Brochure_Specialty_Venetian_Blinds_Horiso_2012.pdf Date accessed 25.06.2013 93 http://www.modernblinds.net/documents/venetian_blinds%28general%29.pdf Date accessed 25.06.2013 91

94

http://www.asiepi.eu/fileadmin/files/WebEvents/WebEvent_6.1/ASIEPI_WP6_WebEvent1_09_ES-SO.pdf Date accessed 26.06.2013

35

3.9.2. Roller Shutters Roller shutters are consists of horizontal bars attached together. For complete sunlight protection, they can be closed and when there is any direct radiation, lifted up position is the best choice. Flexible slats can ensure better radiation gain in specific times. Height of curtain is also adjustable. 85% sun light can be reflected and absorbed before passing to interior space in summer. In winter shading system can be deactivated in order to gain the lowest heat radiations from outside. Automatic aspects controls energy gains effectively that result in lower demand of cooling system in summer and heating system in winter. Reduction of heat loss through the window is according to EN ISO 10077-1:  

2-pane insulating glass (UG2.1 W/m2K) 0.16-0.35 Normal glass (UG > 3.0 W/m2K) 0.20-0.44.96

3.9.3.

Figure 31: Roller Shutters.

95

Horizontal solar fins

Horizontal solar fins are stick out of outer walls to protect buildings from sun. Horizontal systems fulfill protection for south orientation whereas spine solar fins are suitable for eastern and western facades with low sun height. With precise planning efficient sun protection can be achieved. Otherwise static feature results in less efficient cooling, heating and lighting. Normally as this shading systems always exist, can provide a good thermal comfort.97

Figure 32: Horizontal Solar fins

98

3.10. Recommended System System Recommendation Solar Shading

95 96

1. Venetian Blinds (Bamboo blinds)

http://www.es-so.com/documents/KC2-Productsheets_Mai2010_ESSOE.pdf Date accessed 24.06.2013 http://www.es-so.com/documents/KC2-Productsheets_Mai2010_ESSOE.pdf Date accessed 22.06.2013

97

http://www.es-so.com/documents/KC2-Productsheets_Mai2010_ESSOE.pdf Date accessed 22.06.2013

98

http://www.es-so.com/documents/KC2-Productsheets_Mai2010_ESSOE.pdf Date accessed 22.06.2013

36

4. Building energy consumption – After Refurbishment 4.1.

Results of MIT design Software

4.1.1. Building Information:99 Table 23: Building parameters after Renovation Building Location Japan – Osaka Building length, side A 14.1 m Building length, side B 3.3 m Simulation Type Simulation Type four_sided_facade Window Description Glazing Type high performance Window Area 0% Wall Description 2 Insulation R-Value 25 m -K/W Occupancy Type Low-rise Residential 2 Occupancy Load 0.050 people per m Lighting Requirements 300 lux 2 Equipment Load 5.00 W/m Room Ventilation Air Change Rate per 15.0 liters / sec per person Occupant Total Air Change Rate 1.0 roomfuls per hour Lighting Control Lighting Control lights respond to sunlight: all lights controlled by a single dimming switch Representative Room Orientation North Room Depth 4.7 m Room Width 3.3 m Room Height 2.7 m Thermal Mass Thermal Mass Low Overhang Overhang Depth 0m Roof Roof Type Warm deck roof 2 Roof Insulation R-Value 25 m -K/W Roof Insulation Location bottom of roof slab Number of Floors 2 floor(s)

99

MIT design advisor http://designadvisor.mit.edu/design/

37

4.1.2. Primary Energy Use and CO2 Emissions Table24: Primary Energy Use and CO2 Emissions heating cooling lighting total CO energy energy energy energy emissions (kWh/m ) (kWh/m ) (kWh/m ) (kWh/m )

(kg/m )

January

4.1

0.0

4.1

8.2

1.6

February

3.7

0.0

3.7

7.4

1.5

March

2.9

0.0

4.1

7.0

1.4

April

1.5

0.0

4.0

5.5

1.1

May

2.1

0.0

4.1

6.2

1.2

June

2.3

0.1

4.0

6.4

1.3

July

1.1

3.5

4.1

8.7

1.7

August

0.7

5.3

4.1

10.1

2.0

September

2.3

2.0

4.0

8.3

1.7

October

1.9

0.0

4.1

6.0

1.2

November

1.4

0.0

4.0

5.4

1.1

December

2.8

0.0

4.1

6.9

1.4

26.8

10.9

48.4

86.1

17.2

Total

yearly energy

Figure 33: Monthly building energy consumption, before and after renovation

RED heating energy required per square meter of plan. BLUE Cooling energy required per square meter of plan. GREEN Lighting energy required per square meter of plan. GRAY Total energy required per square meter of plan.

38

Before refurbishment

After refurbishment

Lifecycle Energy Cost -- ($ / m2) 2

Lighting Cooling Heating Total

31.7 15.5 66.2 113.4

Before refurbishment

Lighting Cooling Heating Total

9.7 4.7 37.3 51.7

31.7 7.1 9.5 42.7

$/m 2 $/m 2 $/m 2 $/m

After Refurbishment

Yearly CO2 Emissions -- (kg / m2) 9.7 2.2 5.4 17.3

2

kg/m 2 kg/m 2 kg/m 2 kg/m

39

The rates are taken from Japanese Government Ministry law for Electricity and Heating Cost of Heating

1.00

$ per Kwh

Cost of Electricity

0.21

$ per kWh

Years of Operation

15

years

Discount Rate

5.0

% per year

CO2 Emission Rate

0.2

kg per kWh

100

Table 25: Electricity Rates

4.2.

Results of Heating Degree Days Method

These are the results of calculating the U-values after adding the Insulation in each Building Envelope. Here are the following assumptions, considering the k-value (thermal conductivity) of each insulation material as well as the thickness of the insulation materials. Table 26: Calculation of U-values of Wall insulation after Renovation

Materials Ri Concrete Strongly ventilated cavity 30 mm Fiber cement gladding Re

Thickness

λ

R

M

W/m·K

0.08 0.03 0.008 0.118 Total R= U=

1.630

m²·K/W 0.04 0.05

0.240 0.13 7.75

0.03 0.04 m²·K/W W/m²·K

0.13 with insulation Material Thermal insulation. Rockwool Multirock 35

M 0.05 R= U=

W/m·K 0.01 5.13 0.195

m²·K/W 5.00 m²·K/W W/m²·K

Table 27: Calculation of U-values of Floor insulation after Renovation

Floor Materials

Thickness

λ

R

M

W/m·K

m²·K/W 0.17

0.1

1.630

0.06

Ri Concrete

100

http://www.japantimes.co.jp/news/2011/09/06/reference/utilities-have-monopoly-onpower/#.UcsAIfn0F48

40

thermal insolation cork board

0.200 0.01

Re

0.31

0.037 0.043

5.41 0.23 0.17

R= Uf=

6.04 0.17

m²·K/W W/m²·K

Table 28: Calculation of u-Values for Roof after Renovation

Materials Ri Concrete thermal insulation : monrock Hydro isolation Concrete Bituminous layer wood fibre batts drainage layer separation layer Soil Re

Thickness

λ

R

M

W/m·K

0.2 0.200 0.020 0.05 0.004 0.048 0.025 0.004 0.02

1.630 0.025

m²·K/W 0.1 0.12 8.00

0.020

2.50

0.030

0.04

Extra insulation

0 R= U=

0.04 10.76 0.093

0.00 m²·K/W W/m²·K

Table 29: Yearly Heating Energy after Renovation

Envelope

Area m

Exterior Wall Roof Floor Thermal/Cold Bridges Door

202 31.02 64.70

Total Heating energy

2

degree-days tb=

1700 17.96

U-value, 2 W/(m K) 0.20 0.09 0.17

Heat losses kWh

1.6 Σ 2 kWh/m

1756 88 336 5991 146 Heat losses kWh 8318 21.3

41

For the second method of calculation after renovation in which we use the MIT Building Advisor, we outline how each of the four types of loads is computed and show how they can be used to predict the energy consumption loads.101

5. Thermal bridges Basically, where there is a gap between the structural surfaces and materials, thermal bridges happens. Thermal bridges in a building are found at the junction of internal walls with floors and low floors, internal walls and cross walls, internal walls and roofs, the most. These structural thermal bridges also happen when we have an opening such as doors, windows, balconies, etc. The importance of thermal bridges depends on the type of wall or roof of the building, if it is insulated or not.102 The percentage of heat losses in a building depends on the level of insulation of walls, floors and roofs. When a building is not in a good condition in terms of insulation level, thermal bridges represent low comparative losses which is usually below 20%, because the total losses via the walls and roofs are very high (about>1W/m2K) junctions.103 Figure 34: Thermal bridges of Azuma House

Figure 35: Thermal Bridges of Azuma House

Figure 36: Thermal Bridges of Azuma House

101

http://www.ornl.gov/sci/buildings/2012/B10%20papers/192.pdf http://www.ecohousesofvt.com/files/Download/Thermal%20Bridge%20AnalysisForPassiveHouseConsultant s.pdf accessed 22.06.2013 103 http://www.isover.com/Q-A/Implementation/What-is-a-thermal-bridge accessed 22.06.2013 102

42

The Image indicates location of the thermal bridges according to the cross section of the Azuma building.

104

Table 30: Calculation of Thermal Bridges, before and After Renovation Thermal bridges

before renovation

After renovation

Name

Length M

Ψ W/m*K

H W/K

Ψ W/m*K

H W/K

Exterior Wall Parapet Roof between floors

201.88 32.0 32.0 57.3

3.85 4.45 4.45 2.49

1135.8 7.2 7.2 23.0

0.20 0.20 0.09 0.17

57.5 6.2 3.0 9.6

1173.1

76.3

6. FINANCIAL ANALYSIS OF THE REHABILITATION 6.1.

Financial Analysis

Viability for a project refers to the assessment of whether the project has the capacity to meet the defined objectives, and in addition to generate significant financial and economic gains to the stakeholders and to the economy in general. Project Viability depends on a number of factors in addition to economic ones, and the decision to go ahead with a project or not will depend on multiple criteria. The selection or rejection of a proposed project should be made on a number of different criteria. 104

http://contrahabit.wordpress.com/2011/11/09/azuma-row-house-by-tadao-ando-designing-architectureto-purposefully-make-people-feel-uncomfortable/ accessed 22.06.2013

43

6.2.

Estimation of Investment: Table 31: Calculation of Investment

Items Unit Cost($/sq.m) Quantity(sq. m) Total Cost ($) Floor Insulation Cork Board 66.6 64.7 4309.02 Bamboo Tiles (G.F) 0 Wall Insulation 0 Fiber Cement cladding 43 202 8686 Rock Wool 39.7 147.5 5855.75 Ceiling Insulation 0 Monrock 44 31 1364 Wood Fiber Batts 56 31 1736 Glass Panel Blinds 13 35.64 463.32 Total Investment = 22414.09

Unit costs are calculated by simulation and consultation of online markets. Unit Cost includes cost of material, installation costs and other overheads.105 106 107 108 109 110 111

6.3.

Savings Table 32: Calculation of Cost Savings

Before Renovation After Renovation Savings

Total Consumption (KWh/sq.m/y) Unit Cost ($/KWh) Cost($/sq.m/y) 172.2 0.21 36.162 23.6 0.21 4.956 148.6 0.21 31.206

Energy unit cost in japan is 0.21 $/KWh 112

6.4.

Yield & Pay Back period (Static):

Total Investment = 22414 $ Savings = 31.2 $ * 64.7 = 2019 $/ year 105

http://www.houzz.com/ideabooks/1537973/list/9-Top-Siding-Materials accessed 25.06.2013 http://cincinnatipainters.org/how-much-will-a-painter-cost/ accessed 25.06.2013 107 http://www.wikihow.com/Calculate-Price-Per-Square-Foot-for-House-Painting accessed 25.06.2013 108 http://www.naturalinsulations.co.uk/index.php?location=SteicoRigid accessed 25.06.2013 109 http://jum.lt/Building-materials/Insulation/Thermal-insulation/ROCKWOOL-mineral-wool-MONROCK-PRO2000x1200x240mm.html accessed 25.06.2013 110 http://www.buyinsulationproductstore.com accessed 25.06.2013 111 http://www.japanbargain.com/servlet/the-2217/Japanese-Window-Shoji-Blind/Detail accessed 25.06.2013 106

112

http://www.japantimes.co.jp/news/2011/09/06/reference/utilities-have-monopoly-on-power/#.UcsAIfn0F48

accessed 25.06.2013

44

Yield = 2019/22414 = 9 % Payback period = 22414/2019 = 11.1 Y = 11 Years Table 33: Yield and Pack back period

6.5.

Yield

9.2%

Payback period

11 year

Net Present Value (Dynamic Calculation):

Let’s consider - 15 Years business plan - There will be 5% increase in the electricity cost per KWh/ year - There will be 2 % Inflation in market (Also shown by market over years that japan shows 2% inflation) Table 34: Energy saved and Savings

Year

2013 2104 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027

Energy Saved (KWh/Y) Unit Cost ($/KWh) Savings ($/Year) Discounted Savings($/Year) Accumulate Savings ($)

9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42 9614.42

0.210 0.221 0.232 0.243 0.255 0.268 0.281 0.295 0.310 0.326 0.342 0.359 0.377 0.396 0.416

2019.028 2119.980 2225.979 2337.278 2454.141 2576.848 2705.691 2840.975 2983.024 3132.175 3288.784 3453.223 3625.885 3807.179 3997.538

2019.028 2078.411 2139.541 2202.469 2267.247 2333.931 2402.576 2473.240 2545.982 2620.864 2697.949 2777.300 2858.985 2943.073 3029.634

2019.028 4097.439 6236.981 8439.449 10706.697 13040.628 15443.204 17916.444 20462.426 23083.291 25781.239 28558.539 31417.524 34360.597 37390.231

Net Present Value = Sum of the Initial Investment & Present Valued of the Accumulated Savings Net Present Value = 37390.231 – 22414.1 =14976.13 Net Present Value =14976 $

45

We will recover our initial investment in approximately 10 years according to this method while the payback period is 11 years. The difference is because in net present value method is dynamic calculation and includes the 5% increase in energy costs per unit(KWh). Hence savings will increase and we will get our money back in 10 years approximately. I.R.R = 10 Years approx.

7. Conclusion  

Azuma house is a rectangular box single family building constructed by in-situ concrete



Materials used for rehabilitation measures were selected on the concept of sustainability because purpose of rehabilitation of buildings is to cut carbon footprints and make environment greener. But if materials have huge carbon footprints for their manufacturing then it is not much effective to do thermal rehabilitation for buildings.



Practical solutions were selected. It means the investment cost of rehabilitation must be bearable for the owner of the building. Therefore only insulation of building components and solar shading system were advised. Heating system and renewable energy source were not advisable for the building as it doesn’t have any pre-existing heating system or renewable energy source and if they will be introduced then initial investment will be very high and potentially infeasible. Durability and maintenance were other important factors in selection as well.

 

Heating energy consumption has been reduced to approximately 86% after rehabilitation

All over Asia, we have huge number of this type of buildings and same rehabilitation measures can be advised to them as well

Financially profitable as total investment is 22414 $ and saving due to reduction in energy consumption is around 2019 $ .So yield is 9.2 % and payback period is around 11 years. For a 15 year business plan considering 2% inflation and 5 % energy price escalation each year, calculations shows that whole rehabilitation project will be profitable (15000 $ approx. ) therefore chances to get loan from banks are pretty good too.

46