Air Conditioning Lab Unit A660

(ii)

EDUCATION AND TRAINING EQUIPMENT

Declaration of Conformity: Directives

I

(where applicable)

89/392JCEE as amended by 91/368/EEC 89/336/CEE 72/23/CEE

We declare that the following unit complies with the above EEC directives: A660 Air Conditioning Laboratory Unit

The use of the apparatus outside the classroom, laboratory, study area or similar such place invalidates confonnity with the protection requirements of the Electromagnetic Compatibility Directive (89/336/EEC) and could lead to local. prosecution. For and on behalf of P.A. niL TON LIMITED

Technical Director

n Ii~

I P .A. HILTON

LIMITED

Horsebridge Mill, King's Sombome, Stockbridge. Hampshire. SO20 6PX. England. Tel No. National Romsev (01794) 388382 International +44 1794 388382 Fax No. +44 1794 388129 E-mail:

[email protected]

(iii) INDEx.

~ SYMBOLS AND UNITS

2

SUFFDCES and/or STATES

3

SCHEMA TIC DIAGRAM

4

CONTROL PANEL DIAGRAM

6

INTRODUCTION

7

Air Conditioning

7

Air Conditioning Plant

7

Hygrometers

8

Comfort Conditions

8

Human Comfort OPTIONAL UPGRADES Order of Installation INST ALLA TION AND COMMISSIONING Accessories Installation Description Specification Services Required Useful Data Operation Shutting Down After Use Icing at Evaporator High PressureCut-Out High TemperatureCut-Out (In Duct) High TemperatureCut-Out (Steam Generator) RECOMENDED TEST CONDITIONS Humidification De-humjdification Unit Capabilities Energy Transfers MAINTENANCE Earth LeakageTesting Refrigeration Circuit Leak Detection

8

10 II 12 12 13 24 2S 26 27 28 29 29 29 29 29 30 30 30 30 30

32 32 32 32

~

(iv)

~

n,~~! ~1 t

I m

I

Re-charging

32

Cleaning

33

SuperheatControl

33

Manometers

33

Care of Boiler

33

Wet Bulb Sensors

33

Testing the RCCB

34

DETERMINATION

OF HEAT LOSS FROM BOILER

THEORY

36

Composition of Air

36

Behaviour of Moist Air

36

Summary of Definitions and Terms

38

The Psychrometric Chart

41

SAMPLE TEST RESULTS AND CALCULATIONS

44

Observation Sheet

4S

Derived Results

46

SPECIMEN CALCULATIONS

47

Calculation of Air Mass Flow Rate Application of Energy and Mass BalancesbetweenA and B

Boiler - Theoretical Evaporation Rate

D

3S

47

47 . 49

Refrigeration System

50

Application of Energy and Mass Balancesbetween B and C

53

Volumetric Efficiency of Compressor

55

Application of Energy Balance between C and 0

56

To Oetennine the Specific Heat Capacity (Cp) of Air

58

SPECIMENS

61

Observation Sheet

61

Derived Results Sheet

62

A660A DIGITAL TEMPERATURE

UPGRADE KIT

63

Operation

6S

Maintenance

6S

A660B RECIRCULATING Schematic Diagram Introduction

Description

DUcr

.

UPGRADE KIT

67 70 72 73

I ~f: '.':

~~I!

I

(v)

~ In Duct Orifice Calibration Operating Procedure Wet Bulbs Degreeof Recirculation SampleTest Resultsand Calculations AC660A COMPUTER LINKED UPGRADE and AC660B SOFfW ARE UPGRADE Introduction

APPENDICES A: A660A Digital Temperature UpgradeKit Installation Instructions B: A660B Recirculating Duct Upgrade Kit Installation Instructions C: AC660A Computer Linked Upgrade Kit D: AC660B Software Upgrade E: A660C PID Control Upgrade Kit F: A660D Environmental Chamber UpgradeKit

75 76 76 76

77 83 85

2 SYMBOLS AND UNITS Symbol

Quantity Fundamental

--

!l!!i!

A

Area

H

Enthalpy

h

SpecificEnthalpy Current

lit

MassFlow Rate

P

Power

p

Pressure(Absolute)

Q

Heat Transfer

Q R

Heat Transfer Rate

W

Electrical Resistance

Q

Temperature(Customary)

°C

m2 J

J kgA kg Sol W . N m-l or Pa

J

v

Specific Volume

x

Time Interval

mJ kg"

s

Orifice Differential Pressure

.

Relative Humidity

J1

PercentageSaturation

CJ)

Specific Humidity

l\

.Note:

mrn H2O

Changeor Difference Bar = 105N mo:= 105Pa = 100 kN mo]

Presentationof Numerical Data In this manual, numerical quantities obtained during experiments,etc., are expressedin a nondimensional manner. That is, the physical quantity involved has beendivided by the units in which it has been measured. As an example:

p

This indicates that

or alternatively

=

150

loJ Nm-2

p = 150 x I ij3 N m-2 p = 150 kN mol

0 (0 (0

« .. .-

c

::) >'0

(\1 '0 .c

m -I C)

.-c c: 0

..u

c: 0 0

.-L-

«

(/)

~ 0 Q) I 'Q) -0 S:

~ 0 'a

.Q ~ g Q; > 0

c c; E OJ ::; VI

g

~ .PO UJ ~ U C 0 U

'-

0 U) U) Q) 'a. E 0 0

IJ) '--

0 0 CD (0

::::

~

~ ~ "'d ' ~

I

-< ~ ';:!::

QJ

j... Q.,

Q) .00 C,.,)

0

Q)

~

~

~

Q)

~

0

.0.

'

0'

::r.::

~

,

~Q) ~

d ... Q)

~

~

d

s ... n

Q) -R.~"'"

~

~

"'~~Q)

Q)~

... I

~QJ

-

~

0 0 C,.,) U

~

j...

~~~ "0 '0

... I

~... ~ "C Q) ta '

-

~

'-

0

'E~~ o

Oc..~(.J~~

-0 :5 q -'

> a; u Q) 0::

'Q)

9 0

VI

:0

:i8

b u

~

Q; II) c

""Q) c

£t

Q) ':J (.') II) Q)

~

"Q) c

~ Q

'", :;)

~ U

s Q)

-

~ ~ 0 too

8~ ~

~~

~ In

~

tl:

/" '-..I

~

0

~

ii> In ~ U

~ ~ '

~ d

.~

~

ll)

Q)

Q)

d"J

~

d

"","J

-

~ "0 a; \...

I--

~

'-

~

§ 'Q) Q) c

LL a

.Q

~

m

g~~(in'\(tO"\rN

=. a.

(cX3')

i

Q; .c

v -0 ""in 0 E

x w

GI > "0 >

W\:::U

>

0 L.

G)

E ca .c 0 ca

Q)

"0 > ~ 0 0

-s I0 "5 'd) a} C) E 0 Q) t7i

Q) ... :) ~ I/) Q)

-I;..

g 0 ;., I;.s

h "0

u tt u Q)

I~ C C

u. ",-~~ \/01 7\.~!\~

~

6

I 9~

,M"-J'"' "'"T1 0 <

:

w! J

IJI 0 ~ ~ ..

w

~

I

& , ~ ~ g 0

.. ;:. &

f

~

!

" ~

~ I..

f4

it

7 INTRODUCTION

Air Conditionlne Air Conditioning, which may be described as the control of the atmosphereso that a desired temperature, humidity, distribution and movement is achieved, is a rapidly expanding activity throughout the world. Obvious applications for air conditioning are homes,hospitals,public meeting places,mines, shops, offices, factories, land, air and sea transport, but there are numerous other applicatiQnsin which human comfort is not the prime consideration. These include textile and printing industries, computers, laboratories, photographic and pharmaceutical industries, manufacture, inspection and storage of sensitive equipment, horticulture, animal husbandry, food storageand many others.

Air Conditionine Plant Air conditioning plant usllally consistsof a numberof components(e.g. fans, filters, heat exchangers,. humidifiers, etc.) enclosed in a sheet metal casing. Intake to the plant is usually from a clean external atmosphere(plus, in some cases,air recirculated from the building) and delivery from the plant is via ducting to suitable distribution points. Alternatively small self-containedpackagedunits may be used to air condition individual rooms or enclosures.

Components

f1!!m-

Coarse

- usually wire mesh. To remove insects,leavesand other large. airborne particles.

"

Fine-

~-

paper or viscous or electrostatic type. airborne dust.

To removemost of the

are required to cause the air movement and to make good the pressuredrop due to the duct and system resistances.

HeatExchan2er5 - which usually are finned on the air side, are neededto increaseor decreasethe air temperature. Heaters may use stearn,hot water or electricity as the heating medium Coolen may be supplied with chilled water or may be of the direct expansion type in which liquid refrigerant boils at a low temperature within the heat exchanger.

Humidifiers-

are used to increasethe moisture content of the air. Water may be sprayed directly into the air, may be evaporatedfrom a moist surface,or alternatively, steam may be injected into the air. The latter also results in heating of the air.

Dehumidifiers-

are used to reducethe moisture content of the air. This is usually achievedby cooling the air below its dew point so that surplus moisture is precipitated. Sometimeshygroscopicmaterialsare usedto achievedehumidification, but, of course, these require regeneration.

Eliminators-

are speciallyshapedbafflesthroughwhich the air flows and which remove entrainedwaterdropletsfrom the air stream.

~-

are employed to blend two streams of air to achieve a desired condition and/or economy.

~

."'"

W",";, 'r!ijr: ,

c',', : ;

8

..-

Instruments and Controls

are neededto sensethe condition of the air at various stations, and to vary the output of the componentsto bring about the desired final condition. In many installations these may fonn part of a total building system.

energy management

AssociatedEauiDmentmay include:

~

-

for humidification and/or for the air heaters.

Refri2eration Plant - for the air coolers/dehumidifiers.

HV2rometers are instrumentsfor measuringthe,moisture.content of the atmosphere. There are many types of hygrometerranging from the paper hygrometerwhich relies on the change of dimensions of vegetablematter with moisture content, to electronic sensors. Electronic sensorsusually operate on a capacitive principle. Two electJically conducting surfaces are separatedby thin insulating material. This fonns a capacitor in an electronic circuit. The insulating material used is hygroscopic(absorbswater) and changesvolume dependingupon its water content. This changein volume affects the thicknessof the material :md hencethe capacitance. The change in capacitanceis sensedby the electronic circuit and this gives an output that may be sensedby additional electronics and displayed digitally or sent to a computer. Unfortunately such sensorsare relatively expensiveand have limited accuracy(of the order of:!:3% RH). While this is acceptablefor general purposes, it is not sufficiently accurate for use with the Hilton Air Conditioning Laboratory Unit A660. The Hilton Air Conditioning Laboratory Unit employs the well kno\\n wet and dry bulb type hygrometer for detennining air condition. This is the most accurate method and is still used in whirling hygrometers which fonn the standardby which other sensing methods are compared. A brief description of the operation of the wet and dry bulb sensors used on the Hilton Air Conditioning Laboratory Unit A660 are given in this manual in the Theory section.

. ,

Comfort Conditions All animals consumefood (Chemical Energy),do work and reject most ot the unusedenergy to their surroundings principally to the atmosphere.

-

A manrejectsup to about400W (accordingto his level of activity) to tl-.eatmosphere.This heat loss is accounted for by a combination of convection and radiation from his body surfaces, and evaporation of moisture from his lungs and skin. As the air temperature increases,the amount of heat which can be rejected by convection and radiation decreases,thus the evapordtioncomponent must increase. If the relative humidity of the atmosphereis already high, evaporation will be sluggish, skin surfacesb~ome wet, and the person feels uncomfortable. In hot ~ humid conditions, personnelare quickly exhaustedand are unable to maintain vigorous activity. In addition, theseconditions favour the growth of moulds and fungi some of which causeskin ailments.

:

Very low humidities on the other hand.causerapid evaporationfrom the lungs, throat, eyes,skin and nasal passagesand these can also causediscomfort.

Human Comfort Depending upon their physical activity, clothing and surroundings,most people are comfortable in gently moving air (free of draughts) which is at about 20°C and which has a relative humidity of

:

.. ~_.

.f;' 'i\ ...

9 about 50%. However, there is considerable variation of what is considered comfortable between individuals and betweennations, and in any case,there is a zoneof temperatureand humidity around the "ideal" which is acceptableto most people. The prime function of many air conditioning plants. is to provide a comfortable environment in terms of air freshness,temperature, humidity and movement. The Hilton Air Conditioning Laboratory Unit A660 allows the processesgoverning air conditioning to be demonstratedand investigated. It also allows studentsto investigate the measurementand calculation of all the thermodynamic processesinvolved in the heating, cooling. humidification and dehumidification of air. With the addition of optional items the A660 may be expandedto allow demonstrationand measurementof the mixing of tWo air streams,electronic thermometry,computeriseddata acquisition and environmental control. The Hilton Air Conditioning Laboratory Unit A660 and its optional extra componentsare a valuable teaching aid for students in a wide range of courses from technician to graduate level.

t 10 OPTIONAL UPGRADES: The baseunit has a straight-through duct. Product description: A660 Air Conditioning Laboratory Unit The supplied unit will have a product code: A660220 for electrical supply 380/415 Volts, 3 Phase+Earth+N (5 wire supply) 50 Hz. OR A660110 for electrical supply 200/220 Volts, 3 Phase+Earth (4 wire supply) 50/60 Hz. Both units use single-phasecomponents,but require 3-phasesupplies. The total current exceeds normal single-phasecapacity. The loads on the S-wire model are between Line and Neutral 220/240Y. The loads on the 4-wire model are Line to Line 200/220Y.

Installation of the 200/220V 3-phase(4 wire supply) 50/60 Hz model includesthe correct positioning of a wire in the compressorstep-up transformer. Full details appearlater in this section. The following upgrades may have been received, if ordered together: AC660A Computer Linked Upgrade (Factory Fitted) or AC660A Computer Linked Upgrade Kit (Supplied in kit form for installation on site) Installation instructions are contained in Appendix C of this manual. AC660B Computer Linked Software Upgrade (Supplied on disk) Software installation instructions are contained in Appendix D of this manual. A660A Digital Temperature Upgrade Kit (Shipped in individual packing case,accompaniedby packing list) Installation instructions are contained in Appendix A of this manual. A660B Recirculating Duct UpgradeKit (Shipped in individual packing case, accompaniedby packing list) Installation instructions are contained in Appendix B of this manual. A660C

pm Control Upgrade(Factory Fitted)

or A660C pro Control Upgrade Kit(Supplied in kit fonn for installation on site) Installation instructions are contained in Appendix E of this manual. A660D Environmental Chamber Upgrade Kit (Shipped in individual packing case, accompaniedby packing list) Installation instructions are contained in Appendix F of this manual.

11

ORDER OF INST ALLA TION WHEN RECEIVED WITH OPTIONAL factory fitted):

UPGRADES (not

:;tj\;.,: d-,,: ~~,

12

Remove the unit from its packing case and examine it for damage in transit. contact the insurers without delay.

If damage is found,

~

The Air Conditioning Laboratory Unit dissipatesto its surroundingsa maximum of about 6 kW of sensible heat plus 4 kW as latent heat (water vapour) and has an air delivery of about 0.13 m3s'l.

It is desirablethat the intake conditions should be constant,thus, the unit should be placed in a room with sufficient volume and ventilation that ambient conditions are not materially changed when it is operating. The unit must be positioned so that there is no obstruction to the air inlet or to the air flow through the condenser.

ACCESSORIES: C30/2S PF20/2 CS7/8 C30/14 CIO/2 C30/18 A660/6/1 A660/6/2 R633n/1 R633n/2

2 2 I I I I I I I I

A66on/1 SFI/SS SF3/2

I 12 12

SFI/S6 C20/24 IM3/2 1M12/8

12 4 4 4

Rubber Stopper,25mm dia. 300mm Spirit in Glass Thennometer, 0 to 50°C

IM3/5

2

150mm Spirit in Glass Thennometer, 0 to 50°C

Reinforced Supply and Drain Hose, 15mm push fit Stem Elbow, 15mm RI34a PressureEnthalpy Diagram R 134aThennal PropertiesTables EncapsulatedPsychrometricChart, SI units PsychrometricTables, 700 to 1100 mbar SchematicDiagram, A3 SchematicText Diagram, A4 A3 SchematicHolder A4 Schematic Holder Dust Cover M6 SS Washer M6 Nylon Washer M6 x 25 Hex Head Bolt

Wet Bulb Spirit in Glass Thennometer, 0 to 50°C

IM3/6

I

150mm Spirit in Glass Thennometer, -10 to +1 10°C

AS71/4/1

1

Water Measuring Cylinder

C4S/3 A660/IO/I

I I

CompressorCharging Valve Key 10/1lmm Open Jaw Spanner

LAJ/184 AS74/37/1 C20/4

I 1 I

E38/4S

I

Unpacking Case Label Evaporator Gasket Hose Clip, 13 to 20mm 8mm Nut Runner

SF20/l

2

M6 Plastic Fluted Nut Set of Manometer Accessories(Fluid, filling syringe, scales) Product Envelopecontaining: Experimental, Operating and MaintenanceManual Test Sheet Packing List Wiring Diagram

13 Installation Remove complete unit from packing case and check with Packing List Before discarding any packing material ensurethat all items are identified and checkedagainst the Packing List. Ensure the Sparesare also identified. 2.

3 4

Detach the downstream duct from its storage position under the main duct. Examine the two wet bulb to water reservoirs andofrefer to Figure 7fitting on Page 22. toIf the necessary reservoir the correct height I OOmm ~ the duct unit. set.the internal Remove

the bolted supportangle from the evaporatorlower flange and put to one side for

refitting later.

-

Fit the rubber evaporatorgasket(AS74/37/1) and downstreamduct to the evaporatorflange using the M6 x 2Smm hex head screws (SFI/56) and M6 washers(SF3/2) provided. Refer to Figure I on Page 14. Refit the lower support angle on the outside of the duct flange. Ensure that the flange is not over-tightened as damage to the evaporator flange will result. Ensure that the flange is tightened evenly.

6.

Ensure that no powcr connection has yet been made. Refer to the wiring diagrams supplied in colour and Figure 2 on Page 1S for 220V 3ph SO/60Hz units (Drawing No 6602SM) and Figure 3 on Page 16 for 41SV 3ph SOHzunits (Drawing No

66O22M).

.

The 2 x I.OkW re-heaters and duct thennostat in the downstream duct are connectedto the cables in the loose flexible conduit leading from the control panel. Note that the cables are marked with numbers that correspond to the wiring diagrams in Figures 2 and 3. Locate the appropriate wiring diagram for the unit and in Area 2A of the diagram locate the I.OkW Air Heater(First Reheat)and I.OkW Air Heater(SecondReheat). By convention the first reheater is closest to the fan. Using the 415V 3ph 50Hz wiring diagram, Figure 3, as an example. Connect the red wire labelled 253 to one side of the 1.0kW Air Heater(First Reheat). Connect the black wire labelled 254 to the other side and ensure that the black link 254 to 257 is made between both heaters. Connect the red wire labelled 256 to the remaining tenninal A connector block fitted to the downstream duct allows the earth lead from the heaten (green/yellow stripe) to be connectedto the earth lead in the conduit 255. Connect the wires labelled 251 and 252 to the thennostatas shown in the diagram Note that for operator safety it is essential that the earth leads are connectedconectly. Connection of the heaters for the 220V 3ph SO/60Hzunits are carried out in a similar manner with reference to the diagram, Figure 2. Note that in the caseof 220V 3ph SO/60Hzunits the heatersare connectedbetween phasesand connectionsto both ends of the heatersare red. The correct cable numbers should always be observed according to the diagram. Finally. fit the plastic terminal cover to the duct with the hex head screws provided

NI ~ \D \D ~

> 0 N N

V) Z 0 i= u L1J Z Z 0 U

j:

L1J a::

~ L1J to« U.J I

1:

<

U.J ~ tV) Z 3: 0 0 0 ~ ~ 0«

VI t-

~ Z -ffi ~~ H:U o~ ..aIL'

0

~-< - A time

W

36

rI

t"1

I.rI

THEORY (Note: In the following, "stearn" and "water vapour" are interchangeable.) ~

IIe

ti

I

i

Introduction Fresh air contains about 23% oxygen and 76% nitrogen by mass. The remainder is composedof small quantities of other gasesand vapours, and of thesethe most important is water vapour. The vaponr content of the atmosphereis loosely referred to as the HumiditY. Although the water vapour content is usually very small, (usually < 2%), it has a considerableeffect on the rate of evaporation from moist surfacesand materials. An understandingof the moisture content of the atmosphereand of how it may be controlled is an important part of the education of all engineersand technologists.

1

:t , .

,1.

:\., W.i

Behaviour of Moist Air Dalton's and Gibb's Laws give us the following conclusions, (i) Each gas or vapour in a mixture obeys its own physical laws as if it were the sole occupant of the space, at the sametemperatureas the mixture. (ii) The enthalpy, internal energy and entropy of a mixture is the sum of the enthalpies, internal energiesand entropiesrespectively, which each constituent would have if it alone occupied the spaceat the sametemperatureas the mixture.

Examole (See p-v diagram for steam) Let us consider air of specific humidity, i.e. massof steam mass of dry air of 0.0I at atmosphericpressureand 20°C. The density of this air will be approximately 1.2 kg mo) The composition of I.Om} of this "air" will be: lQ.Q.x 12 =

188 kg of dry air (i.e. the gases)

101

-

x

.2

=

0.012 kg of HzO

101

From Dalton's Law the H2O behavesas ifit was the sole occupantof the space(1.0m3). Thus the H2O is at 20°C and has a specific volume of:

-L

= 83 m3 kg"

(Point A)

0.012

From steamtables we seethat at 20°C, VI = 57.8 mJ kg-I and P...= 0.0234 bar (2.34 kN m-2),(Point B). The steam at A is therefore superheatedand at a lower pressurethan 0.0234 bar. At low densities, water vapour very nearly obeys Boyle's Law, thus p" V" = PBVB

p" =

0.0234x 57.8 = 0.0163 bar (1.63 kN m-2) 83

In a stearn/air mixture, the ratio actual ressure 0 steam pressure of saturated steam at the same temperature

is called the RelativeHumidity (+).

j

37

.

~ ..

p

..!;., ...,. _.2

p - V ~grOIl

for SleoII

\ \ 0"°2.34

0016 0.0087

200(

\ ~.B

"*

~

0

c ';::::~~:~:;;

5°(

, x. 0.56

~

v

83

578

147

-;Jkg-:r

Figure 9

If our sample of air is cooled, at constantvolume, to 14°C the steamwill just become saturated(v.

= 83m} kg"' at 14°C, Point C).

This temperature is known as the Dew Point. If the air is cooled, in thennal equilibrium, to a temperaturebelow the dew point, the steam in it must become wet, e.g. if the steam is cooled to 5°C (Point D) when v. = 147m] kg-I, the dryness fraction (x) will be y- = .J1 = 0.56 v. 147 Thus, of the 0.012 kg of H2O in the air, 0.56 ;It 0.012 = 0.0067 kg will be saturatedsteam and, 0.44 x 0.012 = 0.0053 kg will be saturatedwater (liquid).

;tfl'

38 The liquid may appear as mist (i.e. suspendedwater droplets), or as condensationon the cooling surface.

~:

In this example it has been assumedthat (i) the air is cooled at constant volume (ii) the water vapour obeys Boyle's Law

However,the resultsare also substantiallycorrectfor constantpressurecooling over the same temperature range. From the foregoing it will be seenthat if the relative humidity is high, (up to 1000/0)the air cannot

absorbmoresteamunlessits temperatureis raised).

-

The lower the relative humidity, the greaterwill be the readinesswith which air absorbsmore steam. It is now necessaryto define some tenns of reference.

Summary or Definitions and Terms Humidity When an atmospherehasa large water vapour component,(e.g. in a room containing large quantities of exposedhot water), we say (loosely) that the humidity is high. Morc clearly defined terms are: (i)

Absolute or Specific Humidity «I) is the ratio (in a given atmosphere),

moss of water vapour

mossof dry air

(ii)

(~ kg)

Percentap;eRelative Humiditv (cjI)is the ratio,

p. = partial pressure of the steam in an atmospher;;x 100 (%)

p. (iii)

saturation pressure of steam at the same temperature

Percentae.eSaturation (~) is the ratio, mass of steam in a given atmoshperex 100 (%) mass of steam to salUrate the atmosphereat the same temperature

~:

Under nonnal atmosphericconditions, the Relative Humidity=PercentageSaturation(within 1%).

The easewith which the air takes up moisture from any surfaceor processdependsupon how close the air is to being saturatedrather than its absolutevapour content. The relative humidity or percentagesaturation is therefore of greater significance than the absolute Q! specific humidity when drying or air conditioning processesare being considered.

39 Measurementor Air Condition Dew Poin!

The dew point is the temperatureat which the steamin the air becomessaturatedand therefore beginsto condenseto a liquid. Above the dew point the steam in the air is superheatedat a pressure < Pili for the temperature. Below the dew point the water in the air will be a mixtUre of saturatedsteam and liquid water. Hence by slowly cooling a polished metal surface and observing when water begins to condenseas mist, the dew point temperaturecan be determined if the temperatureof the surface is known. The partial pressureof the steam in the atmosphereat the dew point temperatureis the saturationpressure of the water vapour at that temperature. Hence if~e know the atmospherictemperatureand the dew point temperature,we can determine the Relative Humidity with referenceto the Relative Humidity definition. For example, if the Ambient temperatureis 20°C and the dew point temperaturehas been measured as 11°C, from Steam tables Temperature 20°C II"C

Saturation Pressure 0.02337 Bar absolute 0.01312 Bar absolute

Relative Humidity = 0.01312 x 100% 0.02337

= 56.1%

. The measurementof dew point temperature is carried out to measureair condition, but the use of "wet and dry bulb" temperaturemeasurementis more convenient.

II Wet and Dry Bulb Temperature Measurement If a steam of air flows past a temperaturesensor having a wet sleeve of cotton or linen around it, the temperature recorded will be less than the actual temperatureof the air. The temperaturefalls due to evaporation from the wetted sleeveand as a result there is a transfer of heat from the air to the wetted sleeve to sustain the evaporation. The temperature falls to a steady state value called the wet bulb temperaturewhen the rate of heat transfer balancesthe loss of energy due to vaporisation. The actual temperature of the air is sometimes called the dry bulb temperature to emphasisethe destination. The lower the relative humidity of the air the more rapid the evaporation from the wet bulb and the larger the difference between the wet bulb and dry bulb temperature. When the air is saturated(RH = 100%) the wet bulb, dry bulb and dew point temperatureare the same. Since the evaporation.and hencewet bulb temperature,dependsupon the heat and masstransferrates trom the wetted sleeve, any slight draught increasesthe wet bulb depression. It is found, however, that though the wet bulb temperature falls for velocities up to approximately 2 mIs, it remains sensibly constant up to approximately 40 rn/s.

II

40

r

Provided that the air velocity remainswithin this range,the relative humidity can be determinedfrom the wet and dry bulb temperaturesalone. The wet bulb temperaturewithin the 2 m/s - 40 m/s air velocity range is often referred to as the "Sling temperature". The following equation may be used to determine the vapour pressurePv of the water in the air. P.

- P., - 101.325 A (t~ - t..,

= Saturatedvapour pressureat tsli.. kPa = Sling wet bulb temperature ,., = Dry bulb temperature °C

Where p.,

,.,

;

!

A

°C

= 6.66x I O~K" whentsiinS ~ O°C

= 5.94 x

10'" Ko1when t.sI,n. < OoC

(Ref. Chartered Institute of Building ServicesEngineers Guide, Volume C, 1988.) For example, if the dry bulb temperatureis 25°C and the "Sling" wet bulb temperature is 20.6°C, then, From Steam Tables at 20.6°C Psi D 2.426 kPa

Hence,

Pw

=

2.426

-

101.325x 6.66 x 10-4(25- 20.6)

= 2.426- 0.2969 = 2.129kPa

From Steam Tables at 25°C

p., = 3./66kPa

Hence, from the definition,

Relative Humidity =

P.

p2.129 x 100% 3.166 67.2%

The above method allows relative humidity to be determined from wet and dry bulb temperatures and also allows for computerisedmonitoring and calculation of relative humidity. From Relative Humidity and dry bulb temperature all of the other relevant parameters may be determined by calculation, from tables or the psychrometric chart.

41 THE PSYCHROMETRIC CHART While it is possible to calculate the properties of moist air from Dalton's and Gibb's Laws, it is far more convenient to use the encapsulatedpsychrometric chart provided. For the majority of situations the standardlarge psychrometricchart supplied in the spareskit (Part No C 10/2) will be sufficiently accurate. This chart is calculated for a barometric pressureof 1013.25mBar which is a figure for a standard atmosphereat sea level. However. under extreme weather conditions or at-very high or very low (below sea level) altitudes the effect of barometric pressurewill become significant. In order to allow for thesesituations a set of small charts are also supplied that cover the range from 700 mBar to 1100 mBar in 2S mBar steps. In order to use thesecharts measurethe local barometric pressureand convert ifnecessary to mBar. Note:

mBar

= 0.001

Bar

= 100 N/m2 = 0.749mm Mercury

The nearest applicable chart should then be used for all calculations under those conditions. Given any two independentproperties, a state point may be marked on the chart, and from this a number of properties may be determined. The propertiesrelated by the chart are: . (i) (ii) (iii) (iv) (v) (vi)

Dry bulb temperature Wet bulb temperature(sling) Specific volume Specific humidity Specific enthalpy Percentagesaturation (which may be taken as equal to relative humidity)

It should be noted that the specific enthalpy scale is the enthalpy of the dry air ~ the enthalpy of the steam associatedwith it (both reckoned from O°C) but expressedin kJ/kg of 5!!Y. air. Example Observed Wet bulb temperature = 20.6°C Observed Dry bulb temperature = 25°C The state point on the psychrometric chart is located at the intersectionof 25°C Dry bulb and 20.6°C Wet bulb (sling) - see Figure 10, Page42. From the chart it will be seen that, at this state, the air has the following properties: (i) (ii) (iii) and (iv)

Specific volume (v) = Specific humidity (co) = Specific enthalpy (h) = Percentagesaturation =

0.862 m]/kg 0.0135 kgikg 59.3 kJ/kg 67%

The percentagesaturation may be compared with the Relative Humidity calculated from the same wet and dry bulb conditions of 25°C dry bulb and 20.6°C wet bulb. From the chart, PercentageSaturation = 67% By calculation on Page40, Relative Humidity = 67.2%

42

\. ...."...1.. . ..

/

0 I ~. I

/'

'.

.

.

\

I;

I

0.. ..c

.

0-. _:~

.

~~~ ..:

w

..,.

\ \

-0-.\)

1"-..A

..~\ . .

w ;o.~ ,:..:-:!.

-

,---

(") :J:

> ~ -t

~.j

L: ~

..)-. I,

~ ;0

/'"

2 "" III III C 2 "'

~ III '" 0

C ~

~ ~ ~ 2 0 ~ ~ .. 2 n

2

~#

0':-:

.;. w ~

"

.. ..

. ..,..~

~

-,..

~

,..","r-1.1.

.,.jor:';':","";O"~..r-.;

..

0"". .

.,. c

...r0" ~.'.

~_°'J'-

~

..

"co

01

~ G "t ~ " ~.. ~ ~ ~

:

~ '~,;;-::'if:::

..' . o~

.

--

.

=

0 z

1.. I"""\-; C"

~I

~

-< ('") :J: ~ 0 3: m -t ~

I

'!.

of'"

= ~

('")

-e' ~

-

~ qq.

"'0 (/)

... ~

I

."

-c

.-'

. . c .. .

_w 1ft

w 0

0

~ .. 1ft . >.. C .

1ft:: n

.0

.n

.. ..

.. Z )a .. ... ~

;

. )~

,'-fl"'.!~""';"I~r~!.

0: z

I~~: ~.. ~

~..

~ = -~:.""

". ""

-,.

':""""'~:'::';':'.":

';':'::-

.. 00

¥CHSTUlf

(;

..

.s

".

43

CI

,

.~ ~

W Q: => ~ [[

" "I m ~

\D W

44 SAMPLE TEST RESULTS AND CALCULATIONS The following pages give typical observations and derived results from a test with the Air Conditioning Laboratory Unit. Note that if the AC660A Computer Linked Upgrade Kit has been fitted. the test results may be automatically recordedusing the data logging software. The data may then be converted to spread sheet fonnat and analysedon any suitable spreadsheet package. ; All, or any of the processesmay be investigated in anyone test provided that the restrictions given in the RecommendedTest Conditions, Page 30, are heeded. i In the following results, all of the facilities are in use and the changesof the properties of the air, i.e.

and

the wet and dry bulb temperatures the specific enthalpy the relative humidity or percentagesaturation the specific humidity or moisture content

are clearly illustrated and evaluatedby referring to the statepoints and processpaths plotted on the psychrometric chart. It should be appreciated that individual units will give slightly different results and that local atmosphericconditions will have a large effect on the initial condition of the air. I In addition, as statedin Useful Data on Page27, the actual output from all heaterswill be influenced by the supply voltage and this can be calculated using the heater resistance,and the 'local mains voltage which is given by the panel meter. The conditions for the following example test results were: lkW Pre-heating 2kW + IkW Steam Injection Cooling/Compressoron Re-heating IkW Air flow set to a low rate of 3-4mm water gauge (fthe A660A Digital TemperatureUpgrade Kit hasbeenfitted, then eachof the temperaturesreferred to on the schematic diagrams may be selectedand displayed on the digital indicator. ;

45 A660 OBSERVATION SHEET Atmospheric Pressure:

mBar 2

TEST REF. Dry

I.

°C

23.5

Wet

t1

'C

18.3

Dry

tJ

°C

38.0

Wet

t.

'C

29.2

Dry

t,

DC

25.2

Wet

t,

°C

24.7

Dry

t7

°C

37.0

Wet

t.

'C

27.4

Evaporator Outlet

tlJ

'C

21.5

Condenser Inlet

tJ4

DC

81.0

Condenser Outlet

tis

'C

43.0

Supply Volts: Ll to N (415V) or LIto L2 (220V)

VL

VAC

225

Evaporator Outlet Pressure

PI

A

B

Air at Fan Inlet

After Pre-heat or Steam Injection

c

After Cooling/ Dehumidification

n

After Re-heating

Condenser Inlet Pressure

p~

kN m1(g)

290

kN ml(g)

1008 1000

Condenser Outlet Pressure

PJ

kN m1(g)

Duct Differential Pressure

z

mm "10

Fan- -Supply Voltage ----

Vr

100

Condensate Collected

m.

123

Time Interval RI34a Mass Flow Rate

3

4

3.9

x

5

600

iii..,

g 5"

14.2

I

4~ I

A660 DERIVED RESULTS TEST REF.

--

Fan Power (see

Fan

Volts

v.

Fan

Watts -

curve)

P,

kW

0.080

p

kW

,180

p

kW

p

kW

1st Pre-heat Power ,,2/R @ 235V

a

2nd Pre-beat Power V1/R @

C1

Boiler, Lower 2kW Power V2/R @

Q

Boiler, Upper 1kW Power Vl/R @ 23SV

a

p

kW

2.254

Boiler, lkW Power V1/R @ 235V

n

p

kW

ISS

1st Re-heat Power y2/R @ ...,

n

p

kW

2nd Re-beat Powcr V1/R @

(}

p

kW

Evaporator Outlet Pressure

PI

kN m1 (abs)

390

Condenser Inlet Pressu~

PI

kN m1 (abs)

1109

Condenser Outlet Pressure

PI

kN m1 (abs)

.101

Evaporator Inlet

tli

'C

8.0

Condensate Rate

m.

kg/sec

0.205

2

3

4

! 47 SPECIMEN CALCULATIONS From the psychrometric chart on Page 42 the following air properties may be obtained:

I, = 23.3 °C

h"

~ = 18.3 °C

Q)"

= 0.0109kg kg"'

= 38.0 °C

hB

= 94.4 kJ kg"'

t)

51.3 kJ kg-'

= 0.0219 kg kg"

t4 = 29.2 °C

Q)B

ts

= 25.2 °C ~ = 24.7 °C

hc = 75.0kJ kg-' roc = 0.0195kg kg-

~ = 37.0.C

ho = 86.1 kJ kg".

ta = 27.4 °C

(1)0

Yo

From Steam tables:

ll~

= 0.0190kg kg-I = 0.905 m) kg"

11

For the ambient air the enthalpy of the water vapour, h. at atmospheric pressure = 2676 kJ kg-' Boiler feed water, hj at 20°C (assumed)

CALCULATION

m

= 84 kJ kg-'

OF AIR MASS FLOW RATE

From Useful Data, Page27. Air mass flow rate,

APPLICATION

m,

= 0.0517~ ~ "0

ria,

.

m,

=

0.0517

~

~~ 0.101 k! 'y-l

OF ENERGY AND MASS BALANCES BETWEEN A AND B

Using the Fan Power curve, Figure power is approximately 80 Watts.

on Page43, at a fan supplyvoltageof 100 Volts, the fan

'I ,

i

The majority of this will result in heating of the air streams via losses in the motor and friction effects. For the boiler heatersat 235 VL:

'Ii :.~ I~ '" :11

II

Upper 2kW Heater Power =

~ R. 2352 24.S

= 2.254kW

~

lkW Heater Power Rb

2352 47.8 1.155 kW

'itl

il

48

Hence,

.

Boiler Total Po~r InpIlI

2.254

+

1.155

. 3.409 kW

For the 1st IkW Pre-heaterat 235 VL:

-~

Heater Power.

R, =~ 46.8 = 1.lAo kW

'-

..~

Ob

.

3.409 kW

Figure 11 For the system enclosedby the chain line:

By conservation of mass,

m

.

111.«(1).

- (I)..)

. 0.105(0.0219 - 0.0109) . 1.15 x 10-3 iI ~:I

Applying SFEE, Heat Transfer Rate Work Transfer Rate

-

Enthalpy ChangeRate

Heat Transfer Rate. Work Transfer Rate:

= Q. + Q, - -PI = 3.400 + 1.180.. 0.080kW = 4.669kW

49

Enthalpy Change ~ate:

= m.(h. - h..)

- m. h.

= 0.107(94.4- 51.3) -

= 4.515kW

IS

X 10-3 X 84

This indicates a discrepancy of 154 W.

There is also heat loss from the boiler, from Useful Data,Page27, heat loss rate from boiler = 1.33W/K. Allowing for a temperaturedifferenceof 100 - 23.5= 76.5K,theheatlossfrom the boiler is 1.33x 76.5 = ~ . . Other discrepanciesmay be attributed to inaccuraciesin measurement,the use of the psychrometric chart and heat loss from the duct.

BOILER Iheoretical Evaporation Rate Assumptions: ! (i) Steamproduced is saturatedat atmosphericpressureand has a specific enthalpy of 2676 kJ kg"'. I (ii) The feed water is at 20°C and has a specific enthalpy of 84 kJ kg"'. (iii) The rate of heat transfer is 3.125kW 0.102 kW (calculated loss).

-

R

Rate of Evaporation =

Ah

- 0.102 kg ,,"

3.12S

2676- 84 =

t 1~ ._.~

~

x

tn-) I.U

lrn &6"

~-1

This may be comparedwith 1.15 x 10.) kg s.\ obtainedfrom the changeof specific humidity between A and B. ;

.,t~ : ;l: "~?' ..~t.. c"

:\¥t

REFRIGERATION SYSTEM The pressuresrecorded from the system are in gauge units relative to atmosphere. In order to convert these to absolutepressurethe local ambient pressuremust first be added. The ambient pressurewas

1010

mBar

or 0.757mm Mercury or 29.8" Mercury This equatesto 101 kN/m2. 290 + 101 = 390 kN m-t 1008 + 101 = 1109 kn mot CondenserOutlet = 1000 + 101 = 1101 kN mot

Hence, Evaporator Outlet

CondenserInlet

=

=

II

Ii

,I

Note that a measurablepressuredrop exists in the condenserdue to friction effects. The condenser is a commercial unit and as such is designedby the manufacturerswith minimum cost as a prime consideration. The evaporator,however, is purposedesignedfor the A660 unit and utilises oversize diameter tube to reduce the pressuredrop to a negligible value. Using the absolutepressuresand temperaturesrecordedaroundthe refrigeration system,a full cycle diagram may be drawn on a refrigerant Rl34a pressure-enthalpydiagram. The state points may be detenninedas follows. Refer to Figure 13 on Page51 where the state points are shown diagrammatically.

Evaporator Outlet/Compressor Inlet (State Point 1) Locate the 390 kN molhorizontal pressureline and its intersectionwith a superheatedtemperature of 21.5°C (t,J. The vertical Enthalpy line hi at this point is 314 kJ kg-' and the specific volume is 1.056 mJ kg.l.

Condenser Inlet (State Point 2) Locate the 1108 kN m-: horizontal pressureline and its intersectionwith a superheatedtemperature of 81.0°C (tI4). The vertical Enthalpy line hz at this point is 364.4 kJ kg-I.

Condenser Outlet (State Point 3) Locate the 110 kn mozhorizontal pressureline and its intersectionwith the vertical sub-cooled liquid line from 43.0 saturatedliquid condition. It will be found that the point in this case is Q.!!the saturatedliquid line. This indicates that the liquid is not sub-cooled and reinforces the fact that the condenser is a commercial design. The Enthalpy h) at this point is 163 kJ kg"l. After leaving the condenserthe liquid enters the receiver and passesto the expansion valve where it is assumedto expand adiabatically from 1100 kN m-zto 390 kN mol. Hence a vertical line is drawn from State point 3 to State Point 4. The 390 kN mo2horizontal pressureline also corresponds to a line of constanttemperaturebetweenthe saturatedliquid and saturatedvapour conditions at 390 kN mo2. The temperatureof saturation at 390 kN mo2is Soc. The state points are shown on a real R134a Pressure-EnthalpyDiagram for reference in Figure 14, Page 52. The conditions may also be determined from the R 134atables provided. From

the test results the following conditions may be detennined for the refrigeration system: hi

~,

314.0 kJ kg-.

~

l!

II

l!

. .

I

1 I

: 1 f

!

'I I

CI

M m \D \D w

I

OJ

-

+=

:J 0

LOJ (J) C QJ U C 0 U

&OJ (D C OJ U C 0 U

, ~. m'1.1 :i: ~ .-

> ~

v

\ W

,c.Q ~ """ ~ 0 ~

xa. w

La

(. -

a.

a La

d > LU

53

vI

-

h

-

0.056 mJ kg.' 364.4 kJ kg-' 161.9 kJ kg-I 14.2 g/s

1 h

=h

=

J

4

m,.,

APPLICATION

=

OF

ENERGY

.

AND

,~

:/

I

he 9'.' kJ kg-1

MASS

---

BALANCES

"

.

BETWEEN

~-

,

-"'. -

BAND ~

-" "

C-

hC

.

75.0 kJ kg-1

, I

we . 00219 kg kg-I

~

I \

J..L.

\

. ~

-1 .

O. ~7

kg

s

..'~

,

..

h1

(

}

J

\

wC . 0.0195 kg kg-1

,

r:tJ

B

\

I I I

.

'.."

7

I_b:~

..

"

t

"'

~"C~lEnsote 0123kg 116005 iIe 0.205 x 1)-3

314.0kJ kg"'

v1 . 0056m3kg-1

.

~ . 1619kJ kg-1

Figure IS From the observedand calculated data, the following parameterscan be stated for the system that fonns the evaporator of the refrigeration system between Stations B and C of the air conditioning system, Calculated rate of condensation from air stream: = '".(Co). Co)c) = 0.107(0.0219 - 0.019S)

-

= 0.256 x 10-3 q

.I-I

Observed rate of precipitation The discrepancy can be attributed to errors of measurementand the use of the psychrometric chart, to water retention by the fins on the evaporator.and to re-entrainmentof water into the air stream.

Application of the Steady Flow Energy Equation, Heat transfer rate. Enthalpy change rate

- Work transfer rate

There is no work transfer rate between Band C, thus Q,-c

:

(.Thi~ tenn is frequently ignored.)

m.(hc

- h,>

+ m«h; + m,J.h.

- h)

54 m.(hc

- h.>

. 0.107(75 - 94.5)+

+ m.h;

0.205 x 10-3 x 84 kW

= -2.07 kW

m,J-h.

- hJ

=

14.2 x 10-3(314.4- 161.9)

a

2.16 kW



~ ~~

0

::) -

-

c 0 0

a~~ a:\::!}~

Q) U> C Q) "0 C a 0

'-

'0 (,') U1 Q) 'a.

'~

E

0 0

a

h 0

(11 "Q)

I

"0 Q) :r: Q; cr,

;::5

:,.?

Q)

§

Q

-0

~ §

0 Q)

§

~

~~

@)@@@@@@@: M 'J' If) to t'-- IX) OJ t6\rF'\ N N N N N N N,i

- ~ c,

~~

~ Q)

::2if)

.2 0 (u Q E :!J

~ ~; Q

Q)

> "6 >

~ 0

0 -E 0 I... 0

G) E c 0 '>

G)

~ Q) .c ~ 0 ..., ""'\..)

0

::io:



c@

"'6 ... Q)

~ C)

E

0 Q) Vi

~

; cn ~ 1.

0 0 a 0"

w

«i

01 1

I



C Q

'f)

@N

c

-..

~ ~ ...

~ cO

c..>

'-

.

Ck::! Ck:: ~

~"'~ QI

-.. 'coO

~R.,~~

-~

~

""

Q) ~ (,J

C))

~ '~C'~

...

d d "'" e;..

QI

d

~ (I)

o L

Q;: ~

m

,~

v, C ~

rN

~ 0

0 CO

CO c(

~

--

~

()

c

oS

~

-; U -

(I) ~

(::t'! (I:ii'\ ~ ~~.'~~;:~~

C") C\l C/)

C\l

-.. 'tJ d, O"r"' ." ~ C/) ~

.E -l

... .! ~

E

0 ()

c(

d u

~

""d

0

u

~

(\)

d

~

CO CO

~

~ ~ n c:'

~ -.

e

...

H

~d ~

u

UJ (II 0

5J

Q; '-' '.Co! c 0\ ~ c-i)

:£

@

...

a:Q~~

Q)

()

()

-

,:;

@aT"-

C7)

~

-

"Q 0 ~ -0 II'.

> '0 >

Q)

c(

@

-0 'c 0 u

~ '" ." .:u

~ "0 ~

m

(Y)

'...

d

.,.-,

l()

d

C/)

(\)

-.. (\)

~

0 U

V)

~

c(

--' ~

Q)

~ ta ...

=> Q) ...

~ -~""""~ ta

Ii

N

e ~ E g i/1

a '6

lI..

~ a

@

e... Q)

1-1

C)

'-

'Qj ~ 0 c c ,.

c

Q) ~ u

~ (0'\ .-J \N)

0 CO CO

~

0 cu ~

~ a:,

"8 u

'd:

~ '..;;:

'Q) ffi

u n)

Q

GJ

~

II) OJ -'""

~"S

~ i -J u

1&1 CO,..,..

~

Q)

m -'-

"3 a

~ ~

~ ..Q u. "OJ

~ :; u..

(/)

f (J

a

5 01 C '"Q) ~

0)

Qj

«>

@)@@ N@§@@@

~ U

OJ > -0 >

'3 ~

~

In

~

... 0 "5

~

~ 'a

:

1



kN mJ(g)

Fresh Air Intake Differential Pressure

z,

mm HID

1..5

Duct Differential Pressure

ZE

mm H1O

4

Fan Supply Voltage

v,

VAC

A

B

Air at Fan Inlet

After Pre-heat or Steam Injection

c

After Cooling! Dehumidification

D

Arter Re-heating

E

F

Return Air

Fresh Air Intake

Condensate Collected

It

Time Interval

RIJ4a Mass Flow Rate

t

Wet

ffi.

g

I ritm

g 5".

1

J

4

79 RECIRCULATIONIMIXING

From the test results and the psychrometric chart. at the Fresh Air Intake Station F:

z, ttt tlJ V, W, h,

= =

1.5mm H2O 18.4°C Dry bulb 14.loC Wet bulb 0.836 mJ kg.' 0.0082 kg kg"' 39.5 kJ kg-'

~

0.0517 -'

Hence, iii,

~

)

v,

= 0.OS17r:::i:L

~0:i36 = 0.069kg .I-I By conservation of mass this equals the air dischargedat the air exit. At the in-duct orifice Station E:

~ ~ = tit VE = WE= hE -

4.lmm H2O 30.4°C Dry bulb 21.5°C Wet bulb 0.876 m' kg-. 0.0124 kg kg-. 62.5 kJ kg-'

The air passing through the fan in A also passesthrough Station E. mA

:

O.OS38 ~

~~

from the earlier In-duct Orifice Calibration, Page 75. Note that the value obtained for the unit in use should be used. iii

A

~ ~o:m

= O.OS38

.

O.1163q.r-l

80 From Figure 3 and by conservationof mass, the air flow recirculated back to the mixing section

- m-m A , = 0.1163- 0.069

mA- m, = 0.0474kg $-1 Assuming no heat loss or gain from the mixing section (adiabatic flow) and applying the Steady Flow Energy Equation:

.

hA

Substituting for the known values: hA

5.688 01163 ~ kJ kg-I By mass balance,

iii.. w..

~

mF WF + (mA - mF) WE

m, w, + (mA - mF) WE w.. iii..

Substituting for the known values, WA

.

= 0.JX)22kg kg-I Using the intersectionofh,. = 46.5 kJ kg". and w,. = 0.0099 kg kg-I, the State Point A may be plotted (Refer to Page42 PsychrometricChart) and comparedwith the observedvalue from t. and ~" the differences can be attributed to measurementerrors and heat loss/gain from the surroundings. Note that from the Steady Flow Energy Equation and conservationof mass, m.. h.. = mF hF + (m.. - mF) hE mA It can be shown that,

m~-

(mA- m,)

= m, + (mA- m,)

~~ hA- h,.

This is the ratio of From the mass flows

0.069 0.0474 1.4SS:1

A:

,.

Oll

~II

~

011

,.

001

0. 01

i'

.. ~'"

-

° .. . .. . .. , ,., to (IIY

Ala)

0 0 0 ° 0000000000000

.,. r i

~ .-+

5./8~

LN~lNO)

°

°

°

0

~.nlSIOW

°

°

Co 0

. .. .

':~'~~I"::'~'

0

8

..

8

0

'

0

~

I,

s~

~',-,:::~:::"~,~~:-;,,i:=J

~ 09 o,? 0

.. , ,., .. 0 °Q 8 ° 08 ~9° 008 §

..

,'r' .

~

I

~ ,I : ~

~~..}

&.. ~. I'I. I., ;t" .i'!I'J

~

~~

~

-

",.:.

.'.""-

t] ~

# ~

~

.

...!

~

~. ~

T,

~~. ..~';:1. ;.

,:""'"

,

"

"i"

~

n

~,

Tr~~'1:.". i:~I:.;"'~""

.

"II

~. ~.

r;

~ r~

...... ~

to

I n

~ !tJ:iiI! ,;~.

.. oJ

. l' ~ ~~

Y

~ to(

I

0, I.; 101

y ~.. .

. -~ . I >-

i, ~...

.( % ... Z '"

U

\AI L oil

.. '" I~t..

~ ~

.~

.~

...~ 0 ...

..--

~ ':)

0

Q, I.) .,~

y

oJ.

~ 0;.

/ /

"t'

~

.i;: .;. ?(,..~.i"'1~.i

~

~

'l ?,,

-

~"'r~ .f.,,~.

"~>:-.

0 ~"."

)~

83

Ic',::

,. .

IT

85 INTRODUCTION The data logging software supplied with the AC660A Upgrade is an interim measure. Windows software will be supplied without further charge when available. The software provided is a fully operational copy of P.A. Hilton's HEAT97 data logging software with pre-configured tiles that relate to the transducerchannelsin use on the A660 unit. If the AC660A Computer Linked Upgrade Kit was factory fitted by P.A. Hilton Ltd. the configuration files on the disc supplied will be pre-calibrated to match the transducers on the particular machine. If the AC660A was user fitted, the calibration is carried out s part of the AC660B Software Upgrade installation carried out by the user. The GETTING STARTED section of the AC660B Software Upgrade manual deals with initial operation of the data logging software. The pre-configured files for use with the factory fined AC660A are: Channel config.fiIe Conversion Factors file Output file )

66OCHAN 660CON 6600UT

The first screen displayed when starting the HEA1'97 software shows the file names of the. configuration files in use. The file namescan be changed by moving the highlight bar to the line required then pressingEnter. The flashing cursor will indicate that text can be changed. Then pressing Enter again will confinn . the change. Changescan be made repeatedly in the case of errors. Note that if a filename is entered for which there is no pre-configured file, a new file will be created. However, each parameterfor the system will have to be specified.

I

I I

I

Use of the above pre-configured files will ensurenonnal operation until familiarity with the software has been gained. It is recommendedthat the DLS Data Logging SystemSoftware User Guide. DLS/SOFT Issue .01, Ref. August 97 is read in order to expand on the capabilities of the data logging software. For reference.the Hilton Data Logger and Controller Connections,Specificationsand Instrumentation Set Guide is also supplied. This gives details of hardwareconnectionsto the data logger and ASCII serial commands for studentswishing to write software to accessdata directly from the data logger.

~

Free Standing Instrument Case housing a Digital Indicator and 15-way Selector Switch with attached wet and dry thermocouples

~

,

Al A660A DIGITAL TEMPERATURE

UPGRADE KIT

FITTING INSTRUCTIONS

SUITABLE FOR: A660 Air Conditioning Laboratory Unit WITH OR WITHOUT: A660B Recirculating Duct Upgrade Kit OR: A660C prD Control Upgrade Kit

SKILLS REOUIRED: I. This upgrade is well within the capabilities usually found in a Laboratory Technician or similar tradesman. Only fitting of pre-wired thennocouples into the duct is involved. The A660A Digital Temperature Upgrade Kit is built and shipped on a transit rack to obviate tangles. The rack is hung on the rear of the evaporator. Each thermocoupleis unwound in turn and titted in place of a spirit thermometer.

I

The power supply cable is simply plugged into a built in 4-gang socket outlet on the A660. One person can perform this upgrade. Expect the job to take less than two hours. No special safety considerations apply, with the exception of discoMection of electrical and water supplies in some cases,to gain accessto the rear of the unit. Operation of the A660 is unaffected. Temperature data is conveniently gathered at a centJal point.

STANDARD PARTS SUPPLIED: -~--

Q1Y

,

6 3 6

;

DESCRIPTION Transit Rack, containing: Instrument Case with indicator and I S-way selector switch Dry Bulb, Type K Duplex Thennocouple, I SOmmacrylic Dry Bulb, Type K Duplex Thennocouple, IOOmmcopper Dry Bulb, Type K Duplex Thennocouple, 300mm acrylic Power Supply Cable (attached)

PREPARATION: Examine the packing case and infonn the shipping insurers immediately if damaged.

;' ,

2

Unpack and check ofT the contents against the Packing List. Note that the above list is for guidanceonly. The Packing List supplied in the product envelopeis fully detailed and accurate.

),

Isolate the electric and water suppliesto the A660. Disconnectthem, if movementon the castor wheels is necessaryto gain accessto the rear of the unit. Movement may strain or fracture the supply lines.

4.

Remove and retain the existing wet/dry spirit thennometers Store them as a back-up system.

.

I

Note that T9 to TI2 are only used when the A660B Recirculating Duct Upgrade Kit is

il.l~ : Ii I,.

'_l!

A2 fitted. Also note that the flyin2 leads stowed in terminal blocks are only used when the AC660A Comouter Linked Uo2rade Kit is fitted.

u

Iii

Ilj

)\ i'.ll1

fill

tt~ 1 "\:I;, 1\

; I:

A3 INST A LLA TION:

Carry the assembly to the rear of the A660 unit.

2.

Unhook the elastic strap and releasethe instrument casefrom its transit position. Use one hand to hold the case and the other to hold the rack to avoid straining the umbilical cables.

3

that it hangsdown behindthe evaporator.

Place the instrument case on top of the evaporator and engagethe hooked edge of the rack so

.

4.

Rotate the tilting legs beneaththe caseand place on top of the evaporator.

s.

Unwind the wet/dry thennocouplesin turn and tit them into their duct locations or thennometer pockets as applicable. The schematicdial!rams show the correct Dositionsfor TI to TIS.

6. Ensure the wet bulb locates inside the in-duct reservoir by entering centrally and at 90° to the duct.

7.

Use the self-adhesive nylon clips to tidy the routing of the wires. Excess length may be left coiled on the rack.

8. Uncoil the power supply cable and plug into the 4-gang socket outlet. 9.

Ensure the wet bulb distilled water reservoir is filled to the Max level mark.

10. Restore power and water supplies and switch on the main switch. The digital temperature indicator will perform a self-test, then display the temperatureof the selectedchannel. The push buttons on the face of the indicator were used to pre-configure the instrument to read Type K thennocouples. They are not assignedto perfonn any function during nonnal use. Pressing the buttons may disturb the display, but the measuredvalue will return after a short pause. 12. Select each channel in turn to verify correct operation. Each dry bulb will indicate the duct air temperature. The wet bulb temperaturedepressionwill be a function of RH% and dry bulb temperature.

\,r I

I 1

1 1

l

L L

1

I 1

0 CO

CO

«

le-

«

In ''J)

g I Qj -0 ~

~ a

0 ~

0 -.= 'Q) > c

! 0

Q) ~

0

0

~

-

I

m

(;) '-

S:? a (l) J;: (i)

& 0

~ ~

0

U

~

Q)

.,

U) U) Q) '0-

Qi !/1

.:J

..t: (.)

-

.~ ~ CI"}

..0 0 ~

!:l. ... 0 U

Q)

Q)

-

C/)

~

-

§

t..>

I'~ ""

Q..

~

~

-~

~ l()

i

Q) tt ""Q)

~ '"Ci) If) c Q) -g 0 u

c ...

0

\-

~

T) Q)

8 u

"0 ...

~ ~~

Q)

,(,) d

~

.f'"

~.

... Q)

~ ~ ..Q u. c: 0 CD 01 c '"Q; Q:

'-

-= ~ -> >

.g

A~(M\(-::t\(ii1'\~~~(O)\(8\B

~

"(lj

':r

>

G)

'0 >

"8 0 ~

0 I-

0 -0

~ 0 ~ ~

~ ~ G

~ ~ ~ ~ ~ 0 ~ '.,.. ~ ~ ~

@

Q)

> -0

>

& ~ x w

~ 0 "in 0 E ... (i) r

C> >

~

~ v

-c

; Cj G)J .oj

0 ...

E to .c 0 -

~ Q) c:> E 0 Q) (/)

Q)

'5 (I) (J) Q) It. '0

"0 '0 Q 0 > w

1 1

... ~,

-I

0

B-1 --' ~ ~ t.J

~ i:!

~

~ ~ ~

~ ~

too

...

~ (I)

~

""""

-~

~

~ 'J!

~

... tj~

0

~ Q)

QJ

d

~

Q)

100 Q)

-

Co)

too

.O

~ to-

t

~

O)O)QI -~ .~ 'r'

r"

~Q,.~~ ~ J..

~t'-..J:~ ~

~...

C,.) a.. Q)

~ d Q) O)~ 0)

m CD CD

0

«

()

~

-

-

~

...

Q)

-.,..

t\l

~ Q)

C»

~

d

t\l ~

C/) d ... ~~E;..~o::~

CWJ

do~

-.. -..

~

0

(I)

~

~

~

I

I

l

~

~

~~

fP (j)1

~.

~I ~I ' G)

~.

~' 0 f-.: 0 II

J J

1

MI -« m \D \D U LA.)

11 Q C

~ p..

.

,~

10

,

c:

I

I " I .

I < .,

I;I

I

2~~ ~...

CIO

Ie III £

1:~ ~ ... ., '"

I

I~

-I

Iff I

-~ -1 ~

~~ I

n-;

~iI~ Ii:

I~ m ~ .. Go ~ ~ -c

. m

iil!;I~

~

=~.~ I ~..

DS

£J

ffl ,.,

I .I~lo

~D ~

I !

~ 4

-~

-

I

~ .~

I

.$ '"'~

"i I

. ].

1

,-

;r .

I ; ~

~

.~

rT1 n ~ ~ ~ ~

loA,

I

~

Cll STANDARD TOOLS SUPPLIED: A660/10/1 1 IO/llmm Open Jaw Spanner C4S/3 1 CompressorCharging Valve Key C4S/2 I Refrigerant Charging Line C13/63 I 4mm Flat Blade Insulated Screwdriver CI3/62 I 3.2mm Flat Blade Logger Terminals Screwdriver B500/10/3 1 No.2 Pozidrive Screwdriver AC660/3/1 2 3/4 x 7/8 AF OillE Spanner T/I/I I 90° Adjustable Spanner B500/IO/I 1 8" Parrot Nose Adjustable Spanner

TOOLS AND EOUIPMENT NOT SUPPLIED: Vacuum pump Tool kit Multimeter Wire preparation tools

PREPARATION: Examine the packing case and inform the shipping insurers immediately if damaged 2.

Unpack and check ofT the contents against the Packing List. Note that the Standard Parts Supplied and Standard Tools Supplied lists are for guidance only. The Packing List supplied in the product envelope is fully detailed and accurate.

3

The refrigerant flow transducer and the pressure transducers are to be introduced into the refrigerant system. To achieve this without loss of charge, the RI34a must be pumped down into the liquid receiver.

4

Run the compressorto facilitate pumping down

,

Slacken the gland seal on the liquid receiver back-seatvalve then close (front seat) the valve. Retighten the gland seal.

6. The refrigerant in the refrigerant flowmeter glass tube will stan to boil then becomedry. 7.

The suction pressurewill fall to Zero bar (gauge). If allowed to continue to run, the pressure may fall to sub-zero. Ideally, switch QfE the compressorat zero so that opening the systemwill not causeair to rush in to fill the vacuum. A ~ positive pressureis more acceptable.

8

The Rl34a is now retained in the liquid receiver. Close (front seat) the suction valve at the compressor(after slacking the gland seal).

9

Close the liquid stop valve at the inlet to the expansion valve, thus isolating the system to be opened to atmosphere.

\0. Switch off and isolate the electric and water supplies to the A660 unit. movement in the castor wheels will strain or fracture the supply lines.

Disconnect if

II. Open the main control panel to expose the DIN rail by removal of the MS hex retaining screws 12. Leave the A660 in the pumped-downcondition and proceed with bench assemblywork

r

~Nn !'-Z

,

y

cu

0

0

::i::\i rTl

0/

r"I

~,

: z c»m -"'n -i

.~ ~z : z Q)rn \.AIn -f 0 :u oIl rm-< r~

--n Ct C ;;0 m

Ul

~~

°fri:0 VI,

a ?:

rnllIIll

~ ~

~~o~! IEYl:EIPL n I VI

~ /

::t )0-

~ z ~ -I

CJ>-n -or::t

:I: m

~:o 8J>-U) z- ,

>

r 0 G") G) m :xJ

~ r :t> z

< m ~

r'1 n ~ ~ ~ ~

1U1

=

C13 DATA LOGGER PREP~RATION AND FITTING PARTS REQUIRED: PART No. SFl!47 SF3!1 SFl!18 AC660/1fl DLS/l!l

QTY 16 12 16 2 I

DESCRIPTION MS SS Washer MS Nylon Washer MS x 12 Hex Head Screw ~ata Logger Mounting Plate Data Logger with Hex key

Remove the 2mm hex socket screws with the Hex key provided and lift off the Data Logger cover. (Refer to Figure 5 on Page CI2.) 2.

Set the binary identification on Switch S17 (see following page for method). I

3.

Move the Hz jumper ~osuit the electrical supply, 50 or 60Hz.

4.

s.

All thennocouple grounding switches should be,!!r.. The duplex thennocouples are grounded via the digital temperatureindicator. I The power supply must always be set for 240V when fitted to the A660.

6. Refit the cover but use the top four screws only. The remaining screws will not be accessible when fitted to the A660.

7.

Remove the four rubber feet from the baseand fit the two mounting plates horizontally, in their place. ;

8.

Fit the assemblyto the rear of the upstreamduct betweenthe Evaporator and Preheatercover. Threadedbrass inserts:exist in the duct for this purpose. The Logger terminals must be nearest the Evaporator. the terminal label will then be the correct way up.

C14 AC660A LOGGER

-SWITCH

S17. BINARY IDENT SWITCH

The RS232 addressof the logger must be set to identify the type of machine. The first portion of the switch, labelled P & L on the PCB, are for identifying how many loggers are daisychainedtogether. The AC660A utilises a single logger therefore P & L are both set to the off position. 2

The software for the straight through A660 air conditioner will have less temperaturestations than a recirculating duct A660B air conditioner. The remaining six switches.labelled D. E. V. I. C and E. are used to identify the machine. A660 = 25. A660B = 26 and A660C (pID Control Upgrade) = 27. LOGGER NUMBER No.3

No.2

ON

OFF ON

ON

ON

Single Logger OFF

OFF

OFF

No

BINARY VALUE

SWITCH NUMBER

2 3 4 S 6 1 8

OFF

0

OFF OFF

I

OFF OFF OFF OFF OFF

0

-2

P L D E V

I

3 C 4 5

Single logger off, off=O On-I On=2 00=4 00=8 On = 16

E

On = 32

Single logger off, off=O

AC660 Fitted to A660 (STRAIGHT THROUGH) LOGGER No ZERO

Bin ary MachiRe Identity No. 25

2 3 4 S 6 7 I

Off

0

P

Off

I

L

ON

0

D

OFF

.t

E

OFF

2

V

ON

:I

I

ON

4

C

OFF

AC660 Fitted to A660B (RECIRCULATING LOGGER No ZERO

Bin ary Machine Identity No. 26

.. ~

OFF

On=8 On = 16

S E Total = 2S DUCT UPGRADE) 0

P L

2

OFF

3

OFF

4

ON

S

OFF

2

6 ~ 1 ~ .

ON

3

ON

4 S

OFF

On=l

0

-

Single logger off, off=O

0 E

On = 2

C

00=8 On = 16

V

E

Total = 26

CIS AC660 Fitted to A660C (pm CONTROL UPGRADE) LOGGER No ZERO

2 3 4

Binary Machine Identity No. 27

,

6 7 8

OFF

0

P

OFF

I

L

ON

0

D

ON

I

E

OFF

2

V

ON

3

I

ON

4

C

OFF

S

E

Total ~ 27

l

Single logger off, off=O

On=1 On=2 00=8 On = 16

C16 CONNECTIONS

-SWITCH

PANEL TO DATA LOGGER

PARTS REOUIRED: Figure 2 or Figure 3

1 1

PART No. AC660ISI1 SF4/3 SFl/47 SF3/1 SF1Il8 AC660/2/1 HC6SSISII C7/3

QTY I 2 8 4 6 I I 25

Wiring Diagram, Connectionto Switch Panel (415V) Drg No 66OCO5M Wiring Diagram, Connectionto Switch Panel (220Y) Drg No 660CO7M DESCRIPTION Pre-wired DIN Rail Assembly (CT & Volts) M5 Nylock Nut M5 SS Washer M5 Nylon Washer M5 x 12 Hex Head Screw Heater Relay PCB RS232 Socket, Statusand SampleLamps Cable Tie

Removethe 4Ommplug from the baseof the switch panel. This hole will be the exit route for the RS232 connector and other cablesto the Logger. RS232. Status and Samole Lamos 2. Remove the 92mm x 92mm dummy DIN casefrom the hinged lid and fit the RS232 module in place of it. ),

Route the RS232, status and sample cables out via the 40mrn hole. You may prefer to mark these wires now, to avoid confusion when making the connection at the logger end.

Heater Relay PCB 4. Fit the heater relay PCB to the centre of the rear face of the switch panel. Four captive nuts exist for this purpose. The terminal block with short red and black wires should be at the bottom.

s,

Route the two multi-core cablesout from the PCB via the 40mm hole. Wire to the logger later.

6. Connect the Red and Black cables from the PCB to DIN rail terminals specified on the wiring diagram.

Pre-wires DIN Rail 7. Fit the pre-wired DIN rail assemblyto the baseand to the right of the existing DIN rail. 8.

Route the

metre flying leadsout to the logger via the sparecable gland on the right.

9. Connect the short flying leadsto the DIN rail tenninals specified on the wiring diagram above. Note that the wire from the Line Filter must passthrough the Current Transfonner to enable compressorcurrent to be sensed. The redundantcompressorwire may be left in the loom but cut the exposedcopper wires ofT where it was disconnectedfrom the DIN rail. Connect to the Data L022er 10. Route all cables to the logger tenninals through the tnmking provided. Connect all cables to the logger terntinals specified on the wiring diagram above. 12. Tidy excesslengthsand securewith cable ties. Ensurethe hinged lid can be openedand closed without straining cables. J. The 40mm plastic plug should be drilled or punchedout, cut and refitted to protect cablesfrom sharp edges.

C17 CONNECTIONS

-TRANSDUCERS

TO DATA LOGGER

PRESSURE TRANSDUCERS (CHANNELS 17. 18 and 19) PARTS REQUIRED: Figure 4 PART No. IM49/2 CI3156 C6I14 SF1/29 SFI/S4 T/I/I 8500/10/1

Wiring Diagram, Logger to TransducersDrg No 66OC04M QTY 3 3 3 3 3 1 1

DESCRIPTION PressureTransducer,-1 to +15 Bar (gauge) P Clip for pressuretransducer Capillary Tube with depressor M8 x 25 Hex Head Scre..w M8 Washer, 19 o.d. 90° Adjustable Spanner 8" Parrot Nose Adjustable Spanner

Examine the capillary coupling tubes. Note that one end contains a depressorpin and both ends are fitted with an "0" ring. The depressorwill unseata Schraedervalve when fitted to the rear of the pressuregauge,giving accessto system pressure. Fit a capillary tube to each pressuretransducerwith the depressorat the free end. Use two spannerto tighten - one to hold the hex boss of the transducer,one to turn the capillary nut. Detach the pressuregauge housing fi"om the frame plate and rotate it to gain accessto the Schraederpressuretappings. (The housing remains tethered by the system capillary tubes.)

4. Remove the dust caps from the Schraedervalves.

s.

Have the 90° adjustableand parrot nose spannersready. The next operation must be perfOmted smartly to avoid loss of refrigerant charge.

6. Attach the first capillarytube,makingsureit is not cross-threaded.The first threaddoesnot cause the Schraedervalve to open. Finger tighten the nut to reach the "0" ring seal quickly. Finish tightening immediately, using the 90° adjustablespannerto hold the gauge tee and the parrot nose spanneron the nut.

7.

Repeatthis operation for the other two gauges.

8. Fit the large "P" clips to each pressuretransducerand secure to the M8 captive nuts on the pressuregauge housing.

9. The condenserinlet and outlet pressuregaugeswill be indicating pump-down pressureat this time. Do a leak test using soap and water solution to confirm these connectionsare gas tight. A complete system leak test will be done later. 10. Identify the cables to avoid cross-channelconnection at the logger. II. Securethe gauge housing to the frame plate.

1

12. Route the cables to the logger via the tnmking attachedto the condenser. 13. Connect all cables to the logger tenninals specified on the wiring diagram above. Tidy excess lengths and securewith cable ties.

CONNECTIONS

-TRANSDUCERS

DUCT DIFFERENTIAL

TO DATA LOGGER

PRESSURE TRANSDUCERS (CHANNELS 20 and 21)

Channel 2] applicable to A660B Recirculating Duct Upgrade only. However it is recommendedthat it is connected to the Data Logger and calibrated by connecting in parallel with the Duct Differential Manometerfor later use. Once calibrated in accordance with the AC660B Software Upgrade Kit it may be disconnectedand stored. PARTS REQUIRED: Figure 4 PART No. RMXlS/S RMX29/1 C48/2 E2/22 E4/16 IM20/S SFI4/1 CI9/6

Wiring Diagram, Logger to TransducersDrg No 66OC04M QTY DESCRIPTION 6cm 1/4" Nylon Tube 300cm 6rnrn bore Clear PVC Manometer Hose 3 6rnrn Plastic Tee for manometerhose 6 Crimp Terminal, 3.5mm fork 2 3 core, O.5mmCable, 4m long 2 Differential PressureTransducer,0 to 25.4mm H2O WG 4 Self Tap x 9.5 Diff PX 10 Self Adhesive Cable Clip

Cut the 1/4" nylon tube into four equal lengths and fit to the pressureports on the Differential Pressuretransducers. They will then match the inclined manometerport size. 2.

Fit the transducersto the ducting, adjacentto the inclined manometers. Pre-drilled fixing holes exist in the duct for this purpose.

3.

Preparethe 3-core cable by fitting the crimp terminals to the transducerend.

4.

Route the cable back to the logger and apply self-adhesiveclips to the duct or cable tie to the frame to keep it tidy.

5.

Connect the cable to the logger tenninals specified in the wiring diagram.

6.

Connect the manometer hoses by teeing into the existing inclined manometer hoses. Schematic Diagram may be used as a guide.

The

f11 n ~ ~ ~ ~

I~

I A660 REFRIGERANT FLOWMETER ASSEMBLY (PART NO. AC660/6/1J r NOTE ORIENT A TION

FIGUft

6

-=

C19

C20 CONNECTIONS

-TRANSDUCERS TO DATA

LOGGER

REFRIGERANT FLOW TRANSDUCER (CHANNEL 17)

PARTSREQUIRED: Figure 4

PARTNo. AC~6/1 PFI/34 EJ/124 AC66OI3/1

Wiring Diagram. Logger to TransducersDrg No 66OC04M QTY 1 1 1 2

DESCRIPTION Refrigerant Flowmeter 1\2, O.OSto 1.6 I/min 3/8 Flare Copper Gasket Flowmeter Lead 3/4 x 7/8 AF OJDE Spanner

The end fittings must be gas tight on completion. Keep all parts clean 2.

Examine the refrigerant pipelines to identify the location for fitting the refrigerant flow transducer. Below the glass tube refrigerant flowmeter there is a copper tube, 125mm long, connectedto a 3/8" male flare equal coupling. The combined length of these two is identical to the length of the new sub-assembly.

3

Removal of this length must be perfonned with care to avoid breaking the glass tube. Two colTectly sized spannersare provided. Use the 3/4 AF spannerto hold stationary the fitting at the baseof the glass tube. Use the 1/8 AF spannerto undo the flare nut. Tilting the fitting will crack the glass.

4

DiscOMect the lower flare nut and remove the combined tube and male flare.

oS

Blo\v through the flow transducerby mouth, noting the direction-of-flow arrow, to verify the turbine rotates freely.

6.

Note the 3/8" female flare coupling fitted to the outlet side. Refer to Figure 6 on PageC19. A copper flare gasket will provide the seal between here and the inlet to the glass tube flowmeter.

1

Hold the flow transducervertical and drop the 3/8" flare copper gasketinto the outlet side. Use a ballpoint pen to align centrally then hand tighten the complete assemblyonto the 3/82 male flare at the bottom of the glass tube flowmeter.

8.

Couple the flare nut at the inlet side of the flow transducerand tighten both ends using the 3/4 AF and 7/8 AF spannersprovided. Plug in the flow transducersignal lead by locating the keyway, then tighten the nut.

10. The body of the flow transducermay be rotated around the vertical axis, having swivel end fittings. Route the cable to the Joggervia the trunking attachedbeneaththe ducting. 12. Connect the cable to the logger tenninals specified on the wiring diagram. 13. Tidy excesslengths and securewith cable ties.

C2t

- TRANSDUCERS

CONNECTIONS COMBINED

Note:

-I.aH

TEMPERATURE

TO DATA LOGGER PROBE

(CHANNELS

23 and 24)

Channels23 and 24 applicable to A660C PID Control Upgrade only.

PARTS REOUIRED:

Figure4 PARTNo. EJ/6S

1

Wiring Diagram, Logger to TransducersDrg No 66OC04M

QTY DESCRIPTION 30Ocm 5-core Cable (stowed inside the PID enclosure)

The output from the combined probe may be shared between the PID controllers and the Data Logger.

2. Gain accessto the PID DIN rail by removal of the transparentcover.

3.

Locate the coil of cable, which is already connectedto the DIN rail tenninals from where the signal may be taken.

4.

Route the 3 metre cable out via the spare cable gland provided.

5.

Route the cable to the logger via existing trunking or cable tie to the frame to keep it tidy.

6. Connect the Yellow, Clear and Blue wires to the logger tenninals specified on the wiring diagram.

C1.1. AC660A COMPUTER LINKED UPGRADE KIT COMPLETION

OF INSTALLATION

PARTS REQUIRED: E3/249 I E514 2

Ens

3

SFI4/1

4

£4514 £43/3 A660/ICNI C45/3 C45/2

I I I I I

E5/133

,

Data Logger Power Supply Cable, 13A plug 13A Plug 3A Cartridge Fuse 4-gang Extension Lead Self Tap x 9.5 Diff PX External SeriaJLead, 25F 25M to 9F Serial Converter 10/II mm Open law Spanner CompressorCharging Valve Key Refrigerant Charging Line

All channels are now connectedwith the exception of the temperaturechannels. Install the A660A Digital TemperatureUpgrade Kit now in accordancewith Appendix A of this manual, but return to this section before doing a functional test. 2.

If already fitted, simply plug in the tenninal blocks to the logger edgeconnector. Take care not to cross channels.

3

The logger power supply lead must be fitted with the 3A fuse provided Plug into the logger and the 4-gang socket outlet.

,

Connect the RS232 9-pin serial link to the logger

6.

Connect the external serial lead by plugging into the socket at the Status/Samplelamps.

1.

8.

The second4-gang extension lead is provided for use by a computer, monitor or printer, able to use the 220-240V AC available from the A660 socket outlet. This may be at SOor 60Hz. The refrigerant system is now contaminatedwith air and must be leak testedbefore use. This can be achievedby one of two methods: Method I: With Vacuum Pump

I

Removethe cap nut from the compressorsuction valve and connectthe vacuum pump. Set the valve to the mid-position and start the vacuum pump.

2.

Open the refrigerant stop valve at the inlet to the expansionvalve. The vacuum pump now has access to the system from liquid receiver stop valve, through the evaporator to compressorsuction valve.

],

Run the vacuumpump to achieve IOmmHg (Abs) to ensurethat no moisture remainsin the system.

4

Open (back seat) the suction valve, disconnectthe vacuum pump and refit the cap nut

s,

Open the liquid receiver front-seatedvalve to fill the lines with refrigerant pressure,then close again.

6.

Use soap and water solution to check for refrigerant leaks. If available, an electronic leak detector for R 134a is preferred. Rectify any leaks found before continuing.

Method 2: Without

vacuum RumR

Refrigerant pressurecan be usedto push the air out if a vacuum pump is not available. 2

3.

4.

s.

Confirm that the compressor suction valve is still front-seated and cap fitted. refrigerant stop valve at the inlet to the expansionvalve is still closed. Open the liquid receiver front-seatedvalve to fill the lines with refrigerant pr~re, close.

then

Use two spannersto slacken the nut at the entrance to the refrigerant stop valve (at the expansion valve). Allow air and a sma11amount of refrigerant to leak out before retightening. Use soap and water solution to check for refrigerant leaks. If available, an electronic leak detector for Rl34a is preferred. Rectify any leaks found before continuing.

6.

Open (back seat) the suction valve.

1.

Open the refrigerant stop valve at the inlet to the expansion valve.

Functional Test after Air Pur2e I.

2. 3.

4.

Restorewater and electrical supplies. Switch on the main switch, the fan will run and the digital temperatureindicator will illuminate. Observe the Data Logger at the moment of switching on. Refer to Figure I on Page C2 or Figure 5 on PageCIZ. The Sample/FaultLED should flash a few times as it performs a selftest, then go out. This LED will flash each time a logging sample is taken when the computer is connected. The Power LED will glow continuously when power is supplied. Start the compressorand slowly open the liquid receiver valve until fully back-seated.

s. Refrigerant flow in the glass tube flowmeter should become gas free liquid, i.e. no bubbles. (Assuming no significant loss of charge.)

6. The pressure/temperaturerelationship should align with the P-h chart. High pressureis a sign that air has enteredthe system. In this case,refrigerant recovery, vacuum and re-chargeare the only cure.

,.

If satisfactory, continue with loading software and proving all channels.

For referencepurposes,Figure 7 {PageC24 gives the wiring details of the internal serial lead and Figure 8 (Page C25) gives the details of the external serial lead. If accidentally damaged,the leads can be easily repaired.

rT1 n ~ ~ Q :1>-

I~

r m > 0

m x -I m ~ »r V) m :0 }; r

~

St3

Must be preceded by AC660A Computer linked Upgrade Kit

Dl AC660B COMPUTER LINKED SOFIW ARE UPGRADE KIT SOFTWARE INSI'ALLATION PARTS REOUIRED. PART No. AC6fJJB

QTY DESCRIPTION 1 ComputerLinked UpgradeSoftware comprising 31h..Floppy Disk, pre-configuredDEAT97 Software RecordSheet SoftwareUser'sGuide- VersionHEAT97.EXE, Issue1.01DI.SIOl/Soft Copyright Notic~

COMPUTER REOUIREMENTS: IBM PC or compatible; 286 processoror higher; 1MB RAM; DOS or Windows; VGA or colour monitor; RS232serial port COMI or 2, and 31/28floppy drive. PRINTER TYPE: If hard copy is required during logging or data retrieval - EPSONcompatibledot matrix printer connectedto the LPTI parallel port.

PLOTrER TYPE: For plotting am plot overlay of retrieveddata- 2-pen (minimum). RS232serial COMl or COM2. 9600 baudand HPGL compatible. DISK CONTENTS: 1. HEAT97.EXE is the pre-configuredoperatingsoftware. When usedON LINE, the RS232 seriatlink must be connectedbetweenthe Data Logger and the PC. Data may be monitored on screenand savedto disk. 2.

HEA 1'97.EXE may alsobe usedwid1Outthe DataLoggerconnectedwhenOFF LINE hasbeen selected. This facility allows reviewingpre-recordeddata remove from the laboratory.

3.

CONVERT .EXE facilitates export to spreadsheet such as ExcelTM,

4.

TALK.EXE

allows interrogation of individual channels at maximum update rate.

FUroRE SOFrW ARE UPGRADES: Data logging software is suppliedwith this AC660A Upgradeas an interim measure. Windows softwarewill be suppliedwithout further chargewhen available. Windows software will include real time Psychrometric Chart and Refrigeration Enthalpy plotting. Options to display raw data, calculated results, or convert numeric data to spreadsheet compatible format. The logging software, however, will still have a place when training mechanical engineers. Understanding data acquisition, transducers and presentation of data to non-technical personnel is essential. P.A. Hilton Ltd. has been working with the United Nations Industrial Development Organisation to help developing countries to make the change from Ozone depleting CFC refrigerants. The Data Logger has proved an invaluable tool for showing refrigeration plant performance. before and after conversion.

D2 GETfINGSTARTED I

2.

Setup yoor COmplierwid1inreachof thepower supplyandthe RS232serial link connectedto the A6(i} unit. Com:M:ct the serial link to COM I or 2. Usethe 25 109-pin converter if required. DQ00( use a port assigned10a serial mouse.

3. Connectyour Dot Matrix printer to the parallel port, if applicable. 4.

5

After complying widt your local IT regulationsfor virus checkingof new software, copy this disketteto a new directory or folder called HEA1'97. The originals shouldbe kept as a back up. Switch on the A~

to power up the logger aIxi establishserial communication.

6. From the C: drive, doubleclick on REAT97.EKE in its C:\HEAT97 directory. 7

Put d1CDnJseto ~

side. Navigationthroughmostof d1eprogrammeis by useof the up/ve to me LoggerJX)rtdlat dte seriallink basbeen~ted to in 2 above. Press Enter- to switch betweenCOMl and COM2 as appropriate. PressEnter to ~ept. 12. Press M [0 move the highlight to Main menu.

13. PressEnter- to accept

D3

14. PressY to savethe change. 15. A smiley face@ appearsin d1etop left of dIe screen. Note that d1ecentre Red LED is 00, the data logger will flash as each channel is programmed. This can take up to 30 seconds.

16. Wait, then the Main menu appears:

to confirN 17. Press D to move the highlight to collect & Qisplay data, or use the down arrow to move the bar. 18. PressEnter"" to accept.

D4 19. The collect & l2isplay menuappears;

to power up the logger andestablishserial communication. 2.

3.

From the C: drive, doubleclick on HEA~.EXE

in its C:\HEAT97 directory.

Put die mouse to one side. Navigation dtrOUghmost of the progranune is by use of the up/dow,

left/right arrowkeys,- r 1-, or useof the'highlightedor !.lnderlinedletterkeys. 4. The flfSt screenis the pre-configuredSystemconfigurationmenu. For example,

,. 6.

7.

The file namesshould be changedto those shown below. Move the highlight bar to select .c.hannelconfig. file, pressEnter-. Type the new file name66OPRODthen pressEnter again. Repeat the procedureto amendthe conversionfactors and log-allllata file nameto 6roCAL and PROD 1 as shown below. I;

PressL to moveto the Loggerport that the serial link hasbeenconnectedto. PressEnter- to switch betweenCOM I or COM2 as appropriate. I Move to Main menu(henpress Enter-.

DIO 8

PressY to savethe change

9.

A smiley facee appearsin the top left of the screeD.

10. Wait, then the Main menuappears

to confir. ll. Press D to move the highlight to collect &. D;isplaydata, or usethe down arrow to move the bar. 12. PressEnter- to accept. 13. The collect & Display menuappears

to confir8 14. PressEnter""to acceptNumerical display 15. The new list of -.:.tivechannelsis displayed. Note that the Value displayed is in default units of Volts or Hz. The conversionfactors for thesecbarmelshavebeenleft at default:

,

Dll 16. If the A660B Recirculating Duct UpgradeKit is not fitted to your A660 unit there will be no Fresh Air Intake inclined manometer,only a Duct manometer. In this caseChannel21 may be ignored. However, in the event that the Computer Upgrade Kit will la(er be used with an A6WB Recirculating Duct UpgradeKit, or that the A6WB is already fitted, it will be necessaryto calibrate the Fresh Air Intake transducer. If the A660B RecirculatingDuct UpgradeKit is not yet fitted, the Fresh Air Intake transducer may be coupledto, andcalibratedagaimt, the Duct Differential Pressureinclined manometer. 17. Vary the Fan SpeedaJxiVolume Control (ChanlM:121 only) to increasethe ioclined manometer readings from minimum to maximum in Imm H2O steps. At each setting record the volts output for Channels20 and 21. (Photocopythe observationsheeton the next page.) 18. Switch on the compressorto causethe refrigerant flowmeter to function. 19. Run without pre-heatand at minimum fan speedto reducethe load on the evaporator to a minimum. If the recirculatingduct is fitted, 100%recirculationof chilled air will achievethe lowest refrigerant flow rate. 20. Record the Hz (Channel27) and the indicatedrefrigerant flow rate at this setting. 21. Now increasethe evaJX>rator load to maximum(0 achievemaximumrefrigerant flow. i.e. both pre-heaterson and maximum fan speed. 22. Record the Hz and indicatedrefrigerant flow at this setting. 23. Use the data gatheredto constructnew curves and calibration factors for the abovechannels. This may be donelonghandasexplainedin the SoftwareUser's Guide, or by use of third party spreadsheetsoftware. 24. The pre-configured conversion flie must now be amendedto the more correct Kl and K2 values.

~

012 RECORD V ALVES to ~eneratean EXCEL SPREADSHEET Note, depending upon local supply voltage, the maximum manometer reading may be below l2mm H.O. CHANNEL20

DUCT DIFFERENTIAL PRESSURE INCLINED MANOMETER mm H1O

RECORD VDC'

SET TO APPROX mm

RECO_~_~~~~

1. 3 4 5 6 7

.

, 10 11

u ResultiJl,g;calibration factors

1:1-

K2-

CHANNEL 21

DUCT DIFFERENTIAL PRESSURE INCUNED MANOMETER mm 810

RECORD VDC

SF:r TO APPROX IDD1

RECORD ACTU.~ DUn

2 J 4 5 6 7 8 It 10 11 U

~~I!i~_ca!i~~~ factors CHANNEL

K.l-

27

Rl34a VARIABLE AREA FLOW

RECORD Hz

Resulting calibration factOrs

K2-

-~~Q~-';~

KI-

D-

~

I

I'

I

I j

1

or'"G)' Q,) .c U)

~

w

a:

:J

~~ ~~ww Q.a..>a::

.

t Ja::J :J :JCI) o~UCl) CI)~ZW t-woa: ~a:-Q.

~~~~ ~a~~ t-a:-cON

+

-

-0 a..

Q.

-

0 .

~

~

N

-

)(

+

II

E

0

E

N

II

~~

%

E

0

."a~ ~t-° ~-J>

OO~W ~ Wa:z ~a..t-

~d~~

t-~~&L

M -J

0 N

WI- )( Z zc.. octu.

:I:U-

Uc



~C

<

0::

~ 0

~ E ~ N . U);

--

> ~

-~

w ~ ~

> r) .-

~> ~ -..

t="

t..J 0

~ oS .~o =0» 0 . >e O)( N G

...~

~~U .~E E I E E~~ :c

5C1~ .E ~ e~,..

E~N

-t'I!o;

: .

Q:

~

~

f/)

W J: I0

w

a Q:

~ u

§

0

Q..

013

r

1

015

= N

Q

~

-

~

v. C'"')

N 0 0

N VI t'")

Q

.""

-G/~F.C\A0 N 0 N v-

I

I

~

~ ~ ~

. ~ ~> on ~~

~= ~> ~n ~= ~> n~ ~~ ~r..c =~ ~~ ~ ~ 0 ~

'<

n .0 0 ~

I ~...:' IInn .0 0 ~~ ~ C cfn ~

:j-f ..} fWi1 I f .1

~\C ...><

~

~ ~

c. ~

r0

~ ~ ~ ~ ~ ~

n > r=

~ ~ -

' to power up the logger andestablishserial communication.

2.

From the C: drive. double click on HEAT97.EXE in its C:\HEAT97 directory.

3.

Put the mouse to one side. Navigationthroughmostof the programmeis by useofdte up/dow,

left/rightarrowkeys,- r 1-, or useof dtehighlightedor !,!nderlinedletterkeys. The first screenis the last usedSystemconfigurationmenu.

4.

s 6.

Move the highlight bar to select{;.hannelconfig file, pressEnter-. Type the new ftIe name 66OCHAN then pressEnter- again. Repeatthe procedureto amendthe conversionfactors and log-all nata file nameto 66OCON and XXX I as shownbelow.

1.

Move to Main menuthen pressEnter"", PressY to savethe change.

8.

A smiley facee appearsin the top left of (he screen

9.

Wait, then the Main menu appears

018



to c.;onrlr..

--

10. PressC to moved1ehighlight to,CbanDe1 configuration.or usethe00wn arrow to move~ bar II.

Press Enter. me .(:haImel configuration appears !f!i~r""1-,

"'"" -"

1Jrf""

12. Usethe arrow keys(0 moveacrossto the ConversionNo column and down to Channel20. as above. 3. PressEnter- aM the conversionfactors dialoguebox is superimposed

D19 14. Use the arrow key to moveacrossto Kl column. PressEnter- then type in the new KI value from the Excel spreadsheet.In this examplewe changeKl to 1.56. K2 to 5.31.

8:;:.

15. We enteredthroughChaIU1e120 and must exit the sameway. Move the highlight to 20.

s s

0

21 22 23

Polyno8ial Polyno8ial Polyno8ial Polyno8ial

1.56 e

e -29

5.31 5.98 29 29

9

e 9 e

If the FreshAir transducerhas beencalibratedandK 1 and K2 factors are known, then repeat the aboveprocedurefor Channe121starting from Point 12 overleaf. 16. PressM for Menu, the ~hannel configurationreturns:

~

D20 17. Notice the rangehasdefaultedto encompassthe total rangeof a +8V -8V channel. If this is not adjustedto representthe range of likely duct pressures,the resolution of the graphical display would be unsuitable.Ametxl the UpperLimit to 15mmH2OaOOLower Limit to zero: 19 28 21

kN.2 DIFF Px.. H2o FRESHDIFFPx.. H2o COND OUT Px

DUCT

18. Channel 21 may be ~00ed

19 29 21

L L L

1698 lS lS

e k-~

8 e 8

y y y

in the same way

19. The fmal example will be the Refrigerant Flow transducer Move the highlight to select Channel21 for amendment. -

20. Press Enter- to see the conversionfactors dialogue oox channel, input optionsare offered:

21. Press Enter"" aOOchoose frequeocy from the following: 1

21 23 22

~AE$H

2.. 25

AETUtON A~ AETUAN TE"~ ~"'N ~OWEA 1G~ Ae:HE"'T

DX~~P.

--

H~o

AH7. oC WATTS Non-

~

~~~;~;::.,;~.-:0 ~~ P..-J.od ..

23 z',

'-

.--a

e..

Becausethis is a digital input

D21 22.

Press

.

Enter

to

see

17

EUAP

OUT

18

CO

IN

19

DUCT

21

FRESH

29

NO

the

conversion

CONDDIFF OUTP

I1

DIFF

l1li26

28

factors

Polyno8ial

Polyno8ial

dialogue

box:

e 9 9

1 9666 1

e e e

8 8 8

23. Ameoodle CbaIU1el27K2 factor to thenew calculatedvalue. In this example.0.0948g/pulse. 11 18 19 28 21 ~-

24. Rememberto exit via No 27. PressM for Menu or the ~pe returns:

key. the ~hannel configuration

25. Move the highligi)t to Return and pressEnter. Note how the Channel27 unitShavedefaulted back.to Hz. Amend to read g/sec again. Also the rangehasdefaultedto the maximum g/sec at maximumHz measuringby the logger,4(XX)Hz. Amendthe Upper Limit and Lower Limit to the valueson the variable area flowmeter, i.e. 30 and 4.

~""'adl;c ,...~

1S 16 11 18 19 29 21 22 23 lit 2S 26 21 28 29 39 31 32

II ~~1;l8!J

-~~ .c

CC

"c'~~

e e e e e 9 9 59 9 9 9 9 9 9 e 9 8 e

y y y y y y y y y y y y y y y y y y-

D~2 26. PressM to get back to the Main menu. PressY to savethe changesand wait. 27. Verify all ch~ls are oow functioningby logging somedata. Comparethe on screenvalues with the iOOicationson the inclined manometeram refrigerant flowmeter. they should now agree. 28. It is recommendedthat a back-upcopy of the configuration files is madeso that if files are altered in error they can be recoveredfrom the back-up disc. It is recommendedthat the original AC~ pre-configuredsoftwaredisc suppliedwith the AC~B Software Upgradeis usedfor this pnrp>se. 29. The following flies will havebeenmodified as part of the calibrationprocess 6(OCHAN.DFT 6(OCON .DFT

SYSTEM.DFT XXXI To make a back-upof thesefiles copy them from their location on the comguter hard disc to the AC6ro preconfiguredsoftwaredisc. The files will be loca1edwith the HEAT97.EXE programmein the directory createdfor this purposewhen the softwarewas loaded. Note that the files will havethe samenameas the original versionson the floppy disk and ~ copies on the flORD! d~ should be overwritten.

0 n

~ ~