Refrigeration Cycle Demonstration Unit

8/9/2019 Refrigeration Cycle Demonstration Unit

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(ii)

EDUCATION AND TRAINING EQUIPMENT

Declaration of Conformity:

Directives

(where applicable) 89/392/CEE as amended by 91/368/EEC

89/336/CEE

72/23/CEE

We declare hat the following unit complieswith the aboveEEC directives:

R633

Refrigeration Cycle Demonstration Unit

For and on behalf of

P.A. HILTON LIMITED

4,~;._AA

Technical Director

P .A. HILTON LIMITED

HorsebridgeMill, King's Sombome,

Stockbridge,Hampshire,S020 6PX,

England.

Tel No. National Romsey 01794) 388382

International +44 1794 388382

Fax No. +44 1794388129

E-mail: [email protected]


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(i)

POLICY STATEMENT

After Sales Service

We, P.A Hilton Ltd., attach considerable imJX)rtanCen being able to retain die confi(k;nce and goodwill

of our clients in offering an effective after sales service. Every effort is made to answer clients

COrIesponOODCCromptly and to JXOvide a rapid follow up of spares and repi.:ement parts by

maintaining comprehensive stocks of COIDJXmentssually available ex-stock.

Shouldour clients encounterany difficulty in ~g or maintaininga Hilton prodtx;t we would ask

that as a first step dley COIU.:tdle Hilton ~tative in their country or. in me absence f a 1


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INDEX

~

SCHEMATIC DIAGRAM

1

VALVE POSITIONS DIAGRAM

2

SYMBOLS AND UNITS

3

4

4

4

INTRODUCTION

The Refrigeratiooor Heat Pump Cycle

The ValX>urCompressionCycle

INSf ALLA nON AND COMMISSIONING

6

THE mLTON REFRIGERATION CYCLE DEMONSTRATION UNIT:

Useful Data

Specification

Description

10

10

11

13

OPERATING PROCEDURE

Nonnal Operation

EvaporationPnx:ess

Condensation rocess

Shutting Down the Unit

RefrigerantPump Down

Oil Return

Air Venting

IS

IS

IS

16

16

17

11

18

19

19

19

20

20

20

20

20

21

MAINTENANCE:

High PressW'e ut Out

Thennometers

Minjanue Cin:uit B~ (MCB)

ResidualCunent Circuit Breaker RCCB)

Testing the RCCB

Checking or Leaks

Chargingor Rechargingwidt Refrigerant


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23

APABILITIES OF THE REFRIGERATION CYCLE DEMONSTRATION UNIT:

24

emonsb'ation of die Vspour Com}Xession Cycle

.

The Pressme- emperatmeRelationship 27

.

30

.

Demonstration f PumpingOver

31

emonstration f Charging.

32

emonsttationof Effect of Air in a Refrigelation System

.

3Sffect of EvaJX)rating and Condensing Temperatures on the Refrigeration Rate

.

39

ffect of Compressor ressureRatio OIl SystemPerformance

.

43

.

Detenninationof Overall Heat TransferCoefficient

47

.

Generationof a RefrigerationCycle Diagram

Measurement f dIe Effect of Conoonsing emperature n Com~r Power Input 51

0.

53

BSERVAllON SHEET (Blank)

54

141b SATURA nON PRESSURE v TEMPERATURE GRAPH

ss

141bP~SURE-ENTHALPY DIAGRAM

S6

141b COSHH DATA

58

IRING DIAGRAM. R633

59IRING DIAGRAM - 11O-130Vransformer

APPENDIX:

61

. Optional R633A Digital Temper:ature

ndicator

-

Fitting Instructions

67

. Optional R633B Digital Wattmeter-

Fitting Instructions


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of-'

.-

c

:)

1

~

4)

...

=

0)

it

"Qj

~

"-

II

D

~

+-


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2

NORMAL OPERATION

SHUTDOWN


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3

SYMBOLS AND UNITS

Svrnool

kNm-2

ressure f Refrigerant n Condenser

c

tNm-1

ressure f Refrigerant n Evaporator

.

Water Mass Row Rate

dU'OughCondenser

e

1i1.

Water Mass F1owRate through Evaporator

Temperature f Water enteringEvaporattl' oc

t

oc

em~ of Water eavingEvaporator

~

emperature f Water leaving Condenser

,

Temperature f Water enteringCondenser

~

,.

oc

vaporating Tempel8t1n"e

s

oc

emperaturen Condenser

.

oc

,

CompressorDischargeTemperature

oc

s

Condensed iquid TemperabJre

W m-~K-1

Overall Heat Transfer Coefficient

Presentation f Numerical Data

In dlis manual, numerical quantities obtained during experiments,etc., are expressed n a non-

dimensionalmanner. That is, me physical quantity nvolved hasbeendivided by me units in which it

has beenmeasured.

As an example:

p

0' Nm-1 . 150

This indicates hat

p = 150 x 10' N m-2

r

p = ISOkN m°2.

alternatively


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4

INTRODUCTION

Tbe Refriaeratk»D or Heat PumD Cycle:

A refrigerator is defined as a m~hine w~ prime function is to remove heat from a low temperature

region. Since energy cannot be deSU'OYed.ie heat Iaken in at a low temperature plus any other eneJ'gy

inJX1tm~t be dissipated to die SUn'()Undings.H the tempezabJreat which die heat is dissipated is high

enough ro be useful, e.g. for SpIM:;eeating, the ~hine is then called a heat pump.

By selectivedesignof the components he cycle may be optimisedeidler for heat pump applications

or for refrigeration applications. Indeed unckr certain applicationsboth useful functions may be

performedby one machinewhere circumstances enniL For example, n a dairy where refrigeration

is required or milk cooling and storageand hot water s required or OOuIe r tank washing.

The aausius Statement f the SecorKI aw of Thennodynamics tates hat heat will not pass rom a

cold to a ootter region without the aid of an "external agency". Thus. a refrigerator will require an

"externalagency", .e. an input of high gradeerergy, for it to operate.

This energy nput may be in me foon of wrateor a va[X)urwill coodense) s dependenton die

pressure,hus f a suitable luid is introduced t will evaporate t a low temperatm'en the low pressure

evapora1Ortaking in heat) and will condense t a higher remperatW'en die high pressurecondenser

(rejecting heat).

The high IXeSStD'eiquid fomted in the condenser must then be returned to the evaporator at a controlled

rate.

Thus. the simple vapour compression efrigerationcycle has our main components.

(1) An evaporatorwhere heat s taken n at a low tempe1'atures a liquid evaporates t a low p-essure.

(2) A compressorwhich usesa work input to redI.K:ehe ~ure in the evaporatorand increase he

.. pressuref die vapour eing ransferredo die condenser.

(3) A cOIxienser here he high pressure apour condenses.ejecting heat o its surroundings.

(4) A flow control device which controls die flow of liquid 00ck to die evaporatorand which brings

about die pressure eduction.

The refrigeratioocycle is most interesting rom the thennodynamic iew poinL It is one of the few

~tical plants which operateson a true thennodynamic ycle and nvolves

(a) Nucleateboiling and filmwise condensation.

(b) Steady low processes,.e. dn'ottling, compression nd beat exchange.

(c) Row conttOl.

(d) The thermodynamic roperties, .e. pressure, pecifICvolume, emperature, pecific enthalpy and

specifIC nttOpy, f a pure substance t all conditionsbetweensub-coolediquid and super-heated

vapour.

Ald\Ough he vapourcompression ycle is simple o thosewho are familiar widt it many students ind

great difficulty in visualising and understanding te eventsoccurring within the various components.


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5

With dtis in mind P.A. Hilton Ltd., designeddie RefrigerationCycle DemoosuatiooUnit in which die

major pan of the cycle takesp~ inside glass chambers nd can dlerefore be observed.

The unit is a valuable hing aid for studentsn a wide ange f co~ from craft and eChnician

training o first degree t a Universityor PolyteClmic.


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6

IN~ ALLA nON AND COMMISSIONING

Removeme unit from its p.:king caseand carefully examine t for damage. f any is foulKi. notify tile

insurers mmediately.

Stand he unit on a table at a convenientheight aM cl~ to an elec1rical upply, a water supply and

adlain.

Do not stand he unit in a positionwhere t will be in strong direct sunlight or long periods.

This may result in high chamberpressures ith the subsequentossof the refrigerant charge

through he safetY alves.

(i)

The tmit is fitted with two long life fluorescent amps which for shippingare ~ separately.

In orOOro fit the lamps the rear panel of the m.:hine must be removed.

Ensuredlat die m&:hine S NOT CONNEcrED 10 nIB MAINS ELEC1RICAL SUPPLY and

remove die hexagooalbolts and one Dut secmingdie rear panel Note that die bolts are 8mm

across lats and the COn'ect ize spanner s recommended.

The lamp socketsare located nternally and are under die two vertical slots in ~ unit panel.

Carefully remove me lamps from their packing ma1erialand imezt diem in me white plastic

socketson the left hand and right hand sidesof me panel. SUR>Orthe socketsby hand as tm

lamps are inserted.

While me rear panel is removed ensure mat die Residual C1DTCOt iIcuit Breaker switch situated

on DIN rail the right side of the panel is in die ON positioo. The unit will have been left in d1e

ON position when shipped but transit vibration or shock loading can ~ the switched to jwnp

to me OFF position.

(0)

Connectdie mainswater supply o die water nlet at the rear of die unit using he diagooainylon

reinforcedhose. When facing the rear of the machine the water

~

~ on the extreme left

or thepanel.

It ~ recommendedhat the water supply s red through an isolatingvalve that can be

turned ofTwhen he unit is not in use.

In older to increase he stability of the condenser water ftowmeter and evaporator water

flowmeter the conttol valves on thesedevicesare fitted to the discharge ide of the flowmeter.

Hence f externaldamage esults n the flowmeter ubesbeing brokenan external solating valve

will be req~ to stop the flow of water from the unit

(ill) Connectdie remainingwater coupling at the rear of the panel o a suitabledrain using he dear

plastic pipe provided.

(iv) 220/240V Units

Replace he rear panel BEFORE connecting he unit to the mains suWly.

The power supply cable will be foWld emerging rom die rear panel. Connect die cable to a

suitable fixed power supply via a fused outlet (for 5 Amps) which canplies with die ~

regulatioos.

Brown cable

Bloo cable

GreenlY ellow cable

LIVE or LINE

NEtn'RAL

EARTHor groond

Note hat cx safeoperationhe greenlY llow cableshouldbe ~ted to a low impedance

earthing oint hatcomplieswith the ocal egulations.


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7

110/I20V Units

The unit hasan internally fitted transformerwhich is suitable or input voltagesof between110

and 130 Volts (110 to 130V in 5 volt steps). The integral SUWly ~ must be coonected 0d1e

nearest uitablevoltage ennina1s nd mis can ooly be ~hieved by first removing Ix: rear panel

from the unit. The transfonner s locatedon the right hand side of the unit when ooking at the

rear of the machine.

Before connection to dte transfr8fOrnd conde~ cooling water JXx:ke~at dte ends of the evapora~ and

condenser oils.

It is recommendedhat in order to imlXOve he resolution of the thennometers few drops of

light machineoil is OOdedo ~h thennometer


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8

If die djagramsare to be fitted to die panel hen t will be ~- -ry to fit me four clips suwlied

to die ~ of d1epanel.

Auach the 4 spring cli~ to the ~ of 1be -nel using the 8 self-tapping~WS povided. Note

that 8 small pre-drilled holesexist on the ~ of ~ panel o a:ceIX he ~ws.

The clips should be fitted wid the OPEN end king toward the fratt of die panel.

The L shaped lear plastic schematicooldersare dIeDslid under he spring clips.

In order to utilise the plastk COV~ or the unit the L shaped chemabc oldezsmay be removed

and stored under he unit panel


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9

1

2

3

4

Amendments

2 MAINS FL TER ADDED

10.9.97 JB

A

B

c

SlFPL y m -130Y SO/60Hz

SEe HA" ~ aAGRAH F~ TERttNAL KEY

[Drawn y

JBhe ~ier is req.jred to deliver goods strictly ~cordi-9 to

drowing. Component nspection is the suppliers responsibiity

R8IIIDveoil sharp edges a~ burrs.

[

Checked

by:

Dimensions: mm

@Q

rojection'

Issue: 2

Date:4.3.96

Scale.

-

no/rig. 1

ENGLAND

Limits unless otherwise stated

Fractions * 1/6"

Decimals * 0.25 mm

I DRG. No.

633365

110

-

130V TRANSFORMERWIRINGDlRGRAM

TITLE:

MTL:

FIIIISH:

KINGS SOMBORNEHAMPSHIRE

. A. HL TON l TO


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10

THE HD..TON REFRIGERAnON CYCLE DEMONSTRAnON UNrr

USEFUL DATA

Condenser:

Wal« coil surf~ area: O.O32m3

E VSDOratOC

Water coil surfacearea: 0.032012

Specific beat capacity of Wafa' c,>: 4.18 kJ tg"1 K-1

Refri~erant:

R141b

1,1,dicbloro-1- flooroetbane

Quantity: approximately800 cm' (awroximately 1 kg)


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11

SPECIFICADON

Compreaor

Hennetic ype ~pressor with inlegrall/2

H


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12

of die StaDdaIdpanel and may easily be fined by the CUSfDm~.or if

purchased widt the standard unit can be a f~tory fitted 0IKia1.

SAFETY

No moving parts.

Intemally mounted relief val~ ~t to 2SOkN m"2 gauge fitted to

cOIxIen= aOO vaporator.

High ~ure cut out fitted to stop compress


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13

DESCRIYnON

(please efer to me schematicdiagram on Page 1)

All COlDJX)nentsre mounted 00 an attractive durable glass reinfrator.

On entering the evaJX)rat(X"he low pressure iquid aOO aJX}ur eparate. he liquid passing nto the

"pool" for re-evaporation.while the vapour mixes with the vaJX}ur roducedby the boiling ~tion of

the water coil. The vapour mixture then returns to the compressoro repeat he cycle.

In the standardunit instrumentations provided to measure:

(i) The tem~rature and pressure f die refrigerant vapour n die evaporatorand condenser.

(ii) The tem~rature of die water entering and leaving die coils in d1eevaporatorand condenser.

(ill) The water flow rates hroughbodi coils.

(iv) The tem~rature of die oot gas eaving the canpessor.

All temperatures re measured n die standardunit using red spirit dlennometers.

An optional digital temperatW'epgrade it is available hat allows measurement f the temperature f

the condensediquid te as well as the above ist of temperatures.

With the addition of this optional upgradedie completecycle diagram may be plotted on an R141b

pressure-enthalpy iagram.

An isolating valve is fitted at the condenser utlet and this may re cl~ed to ~onstrate a technique

used in refrigeration maintenaocewhere the refrigerant charge s collected and contained n the

conde~ or in most CMesa specialisediquid receiveradjocent o the condenser.


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This ~hnique is imJX)rtantn onk:r to demOOSb'ateow to pevcnt ~ escapeof refrig~t during

maintermnce.

In common with all refrigeration and heat pump systems he unit containsa small amount of oil for

lutxication of ~ CaDpessa. During normal operation~e oil. in die fOOD f mist and oil/refrigerant

~Iution is carried from the compessor to the condenser nd ultimately to die evap


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IS

OPERATING PROCEDURE

(please refer to Figure 1- SchematicDiagram, and Figme 2 -R633 Valve Positionsdiagram)

To assiSt n unOOrstandingration. item namesand relevant tems on the two scoomaticdiagrams

suppliedare refelTed o in bold type in the following sections.For example.Refrigerant Pump Down

on Figure 2 and Condenser or Evaporator etc on Figure 1.

The five baD valves shown on the two schematicdiagramshave been nsIalled for ~ ~

Figure 2 (Page2) diagram shows he four standardvalve combinations.

The vent valve on die condensers namally only openedbriefly to vent air from the systemaId this

is referred o elsewhere.

Note mat when the mrlt is shut down the ball valves should AlL be in the closed positioo. This

preven~ the refrigerant migrating to the lowest temperature art of the systemdue to vapourpressure

effects and in most ~s dtis would be the compressor asing as this will respond most rapidly to

variations n ambient emperature.

Normal Ooeration

To start the unit first turn on the cooling water supply and the mains supply to the unit

Open the valves ndicated n Figme 2 (Page2) for Normal Operation.

11ris llowsvapour o be


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16

Unlessdie supply water emperatures high men altera1ion f ~ evaIJ


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17

Normal running condition is widl aPJK'Oximatelyo-25mmof liquid in the bottom of the condenser

chamberand dle float valve maintaining his level constanL

Once normal operatingconditionshavebeen~hieved men me main switch shouldbe turnedoff. The

compressorwill stop and me lights on the unit will be extinguished. If the optional temperature

indicator has been itted the display on this too will be extinguished.

Turn off die cooling water suWly to die unit It is recommended lat die (water) control valves are

left open so that f die usersuppliedexternal solating valve eakswater will be allowed to run to drain

and will be noticed more readily. In addition, f conditionsare such hat the water supply s likely to

freeze dlen leaving die control valves on the flowmeterSopen may not prevent die glass ubesbeing

broken but it will make breakage ess ikely.

Once he unit b$ been urnedoff then me ball valveson me unit shouldbe closed o mimic me

shutdowncondition. SeeFigure2 (page2).

This will prevent the large volume of refrigerant contained n the evaporcUormigrating into the

compressor asingdue o vapourpressure hanges.The small volume of liquid in the condensermay

migrate to the compressor nder certain ambient conditionsbut this is no cause or concern.

Refri2erant Pumo Down

This is a procedureoften used n industrial and commercial efrigerationpractisewhere die refrigerant

charge s condensed nd collectedeidier in the condensertself or more commonly n a liquid receiver.

In die RefrigerationCycle DemonstrationUnit R633 die condenser nd liquid receiver are combined

in die sameglass cylinder.

In order to carry out pumping down dte unit shouldhavebeenoperatingnormally f


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18

cooling water aM evaJX)rator ater flow rates are left as for normal nD1ningand me unit remaim

switched00. The only pam from me evapa-ator o the compressors via the capillary tube.

The oil in the baseof the evaporatorwill start to flow mrough the capillary blK:t to the com~

casing.

The evaporator chamber may be at low JXeSSure nd therefore the oil return process will be slow due

to the low differential pressure. This may be increased and the ~ speeded up if a small amount

of refrigerant liquid is OOmitted o the evalXJ[ator by briefly opening the ball valve at the base of the

condenser. However DO NOT leave this valve open.

Once the oil has been eturned o die CODlpresD' asing d1endie ball valves may be ~ to dx:;

position for normal operation as shown n Figm'e2 (page 2).

Once die operating coOOiuons have rewrned to noonal and the liquid level in the conde~ is

apJX'Oximately2O-2Smm tOOn OOunit may be eithez shut oown as described ai)Ove or adjusted for

further experiment.

Air Ventin2

A vent valve is siwatedon dle top of the con


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19

MAINTENANCE

Hi2b Pressure Cut Out

At regular ntervals and according o the local safety regulations he high pressure ut out shouldbe

testedas follows:

Start dte unit as detailed for normal operation in the operating procedure 00 Page 15 and

operatewidt a modezate ooling water flow to both dte condenser nd evaporaror s detailed.

Allow die unit to warm up and hen cl~ the control valve on the condenserwater nowmeter.

This will cause he condenserpressure o rise. At approximately22OkN m"1 he compressc.'

shouldbe shutdown by the nternal high pressure ut out An audible click shouldbe heard rom

the cut out device.

If the compressor oesnot turn off automaticallyat a oressure f 230kN mol hen turn off the

unit at the main switch. It will then be necessary o adjust the pressure switch as detailed

below.

If the compress


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20

Th~ differencesmay be added B'subtlaCtedrom dJe~ as awropriare.

If greater~uracy is requiredmen he water may be gently warmedand me diff~nces notedat ~vera1

temperatures. In d1is case a graph of indk-lt~ against difference should be plotted for ~h

th~omeleJ' .

H the optional temperature indkator hasbeen itted then d1eaOOveiffera1sitionwhen he unit is not in use

Cbeckinl for Leaks

If a leak in the refrigerant circuit is suspected. e.g. if d1ere s a loss of refrigerant from the system, me

following procedlD'e should be adopted:

(A) If tOOres refri9.erantn the system:

~e die unit in a WanD laceuntil its temperatureea:hes32-3SoC.The pressure hrooghoutdie

systemwill now be aboveabnospheric JKIdie leak may be loca1ed i~ by

(i) Applying a Sb'Ongmp or detergentsolution to all joints,

(ill Using an electronic eak detector.

(B) If there s no refrl2erant n the System:

Pressuriseme system o SO N m""wim air by applying a manualpump.e.g. motOrcar tyre ~p.

to me charging valve at me baseof the evaporator. The leak may then be located as n A.


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21

Cbarg2 or Recharge

Under nonnal conditions me vapour press\U'e f die refrigerant does not reach abnospheric pressure Wltil

die liquid is at a temperatme of approximately 32°C.

In order. merefore. o make charging me unit simpler. the one bip can supplied by P.A. Hilton LId

containsa small amolDltof Niuogen gas n order to raise me internal press\D'e rtificially.

Before charging t is recommendedhat me unit is set up in me following way:

Start die unit as detailed for normal operation in die operating procedure on Page 15 and operate

widl a moderate ooling water flow to bodl die condenser nd evaporatoras detailed.

Allow the evaporatorpress1D'eo reduceand then position the ball valves or shutdown condition (see

Figure 2

-

Page2) and

bJrn

off the compressor. Note that if the unit is not chargedand containsair

then t may be necessaryo vent this from the condenser ia the vent valve on the condenserop plate.

The unit s now~y for charging.

The chargecan only be released rom the can by using the brasschargingvalve (VCl7/2) supplied n

the accessaieskiL

Unscrewdie small brasshexagonalnut from die chargingvalve and screw diis onto die dtreadon die

top of the can. Screw die rest of the charging valve (VC27 l.) into the straight connector on die

refrigerant charging ine (C45/2), also supplied n die accessories it

Remove he brasscap from the fixed charging valve at the baseof the evaporatoron the R633 uniL

Note that the angled end of the refrigerantcharging ine hasa b~ pin in the. entreof the connector.

This end should be connected o the fixed charging valve on the baseof the evaporatOr.When d1e

connector s screwed ight the pin depresseshe centre of the fixed charging valve and allows access

to the evaporator.

The can should be inverted and me two components f the brasscharging valve should be screwed

togetherby rotating me can. SeeFigure 4, Page22. When the components f the charging valve are

screwed ogemerme refrigerantwill flow into me charging ine due o me nittOgenpressuren d1e an.

Open me ball valve at me baseof me evaJX>ratornd me refrigerant will flow into the evaporator.

Switch on die writ and d1iswill again educedie evaporator ressure nd assistdie flow of die

refrigerant into die evaJX)rator.

When the iquid level in the evaporatOrs above he level of the tOpcoil close he ball valve at the base

of the evaporatOr.

Allow die unit to run under nonna operatingconditions until die liquid level in die condenser as

stabilised. Ensure he liquid level is still above die top coil of die evapomtol. If this is not die case

then open he ball valve at die 00seof die evaporatorbriefly until d1e equired evel is ~hieved.

Unscrew he charging ine from the can and this will close he valve in the can. The ball valve at die

baseof the evaporatorcan be briefly opened o draw in any liquid remaining n die charging ine.

The chargingprocedure s likely to result in someair entering he system. To remove he air follow

the procedure or Air Venting describedon Page 18.


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22

0,. Tr~Can

RMX74/1

-

Figure 4

Bras.C~gi'1g

Valva VC27/2

rn

B

Refrigerant Charging

Line CI.5/2

IN c~~

Valw With Centre

Pin

Angled Comector

With Central Pn


27/76

23

CAPABILmES

OF THE REFRIGERATION CYCLE DEMONSTRATION UNIT

Demonstration of vaJX)m' ompressioo refrigeration or heat pump cycle widt visual observation of

the important ~.

2. Investigation/demonstmtion of d1esaturation pressure-temperature relationship during evapoIation

and con~nsation.

Demonstration of "plDlping over" or "pumping down" into the condenser.

.

Demonstrationof charging.

.

5.

Demonstration f effect of air in a refrigeration system.

6. Detenninationof effect of evaporatingand condensing emperamres n me refrigeration rate and

condenser eat output

7. Investigationof die effect of compressor ressure atio on systemperfonnance.

8. Deterntinationof overall heat ransferbetweenR141b and water n the evaporatorand condenser.

With the addition of the optional temperature indicator:-

Generationof a refrigerationcycle diagram on a pressure-enthalpyhart.

.

With the addition of the optionalwattmeter:-

10. Measurement f me eff~t of condensing emperature n compressor ower input.


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24

1. DEMONSTRA nON OF VAPOUR COMPRESSION REFRIGERA nON OR REA T PUMP

CYCLE

The ex~cnt shouldbegin wid the unit at rest.having been eft in die shutdown (SeeFigure 2, Page

2) condition for some ime in order for all of the compo~nu to be at a similar ambient empelabD'e.

Open he ball valveson the cylinders as for normal operation (SeeFigure 2, Page2) but do oot bIrD

on die unit and do not bIrD on die water supply to the evaporatorand condenser oils.

The stu1D".

Reference houldbe made o the Pressure nthalpy diagramon Page55 or the argee~uJaIed

diagram C57/10) supplied n the accessoriesit

In order to changephaseat constant X'e8Sure,nergy s required o increase he endlalpy of me

vaJX>ur. his energy s taken rom the water passing hrough he evaPnhe water nlet tem~rature and the ocal ambient em~rabJre, he surroW1dingtmospbete.

If the water supply temperature s high (awroximately 16OC r mur ubbles are being prodtx;ed rom me evaporaUX'oil within the evaporator

chamber hen heat is being exb'Xted from me cooling water flowing through the coil. If the

evaporator nlet water tempelabJrel is examined after several minutes operation and this is

comparedwith the water discharge emperature the discharge emperatm'e hould be fouOOo

be slighdy lower than the inlet tem~. In


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25

addition, dependingupon me local ambient conditions,water vapour will also condense n die

outside surfaceof me glasscylinder and baseplate. The change n phaseof me water vapour o

a liquid will in itself IX'Ovioo eat o causeevaporation f die refrigerant n me chamber.

In addition, f the evaporator ooling water flow is stopped hen the rate of condensationonning

on the condenser oils will also reducedue o me reduced apourgeneration ate n the evaporata-

and me reducedvolumettic efficiency of the compressor nd ncrease n specific volume of me

vapour generatedn the evaporatorchamberat low pressure.

(ill) With the evaporatorand condenserwater again flowing as described n the normal operation

conditions on Page 15 the condenser ressure houldbe observed.

The condenser ressmewill be seen o be higher than that of the evaporator. This is obviously

due to the compressor. The ratio of condenser ressure o evaporatorpressure.PJP.. is known

as the compressorPressureRatio. This will vary ID1der ifferent operating conditions and may

be investigated.

After the W1ithas been nmning for several minutes under nonna conditions the condenser cooling

water inlet temperabD'eand the discharge temperawre should be compared.

It will be found that the discharge emperature , s greater han the inlet temperature ..

This is due to the heat given up by the hot high pressure as entering the condenser rom die

compress


30/76

26

As soon as the liquid passes hrough he expansion alve U pressure rops o awroximately the

pressIU'enside he eV8lXX8fOr. his ~ me liquid to immediaIelystart o changephase rom

liquid to V81XXJr. s in the evaporatm' ragy is required o bring about me phasechangeand

someof this is taken from the baseplate of the condenser the expansion alve is ~hcd to

the hue plate.

ExtrlK:tingbeat rom me baseplate edIx:ests te~ and his n bIrD educes he tem~nue

of the condenseriquid at me baseof the condenser.This results n ~ liquid being "sub cooled"

below its satUIation empelatm'e.

If the optional temperature indicator is fitled ~ an IKiditional thennocouple r. is supplied to

be fitled in the base of the colxleDSQ" hamber. Hence the sub cooled liquid tem~ may be

measured and this together with the other measured remperattlreSand pressures allows a complete

refrigeration cycle diagram to be plotted on the pfeSSW'C-enthalpy iagram supplied.

In the condenserrerefore the refrigerantchanges rom superheated apouron entry. through o

sanuated apour hen to sabJratediquid and ultimately to sub cooJediquid before t leaves he

condenser hamber.

As ~ refrigezant~ along the pipe leaiing from the exlBn8ioo valve to the eValJ(Xatoreat

will be exb'.:ted from the SUn'Oundingsnd ~ liquid will be further converted o a v8fX)Ur.The

si,ht ,- just before nb'y o the evaporatorllows he iquid/vaJX)urixture o be ~ed.


31/76

27

2..

PRESSURE TEMPERATURE RELATIONSHIP

The relationshipbetweensanuationpressure nd temperaturemay be observed n both me evaporator

and condenser. However as variation in the evaporating emperat1D'es small for aU but extreme

changes n cooling water flow me condenserX"Ovides

moregraphicllustration.

As the conoonser contains refrigeJ'ant n all stages rom superheatedvapour through to sub cooled liquid

the dlermometer pocket ~ only records temperatures close to saturation when die pocket is showing

signs of condensed liquid Therefore it is recommended that die pressure temperature relationship in

the condenser is investigated as the condenser pressure increases.

If the pressure empemture elationship s investigated y reducing he condenser ressure hen the ft

thennometerpocket will be at a tempenuure hat is higher than the surroundingvapour due to its

thermal nertia. Thereforeno vapour will condense n the pocket and an inCOIreCtemperaturewill be

measured.

Note that dJepressures referred to on dJe pressure-enthalpy chart and on the p-essure-temperature chart

on Page 29 are "absolute" values.

Absolute pressure=Pressure gauge value + Local abnospheric pressure

Procedure:

(i)

Start the unit for normal operation as shown on Page 15 but iocrease the condenser cooling water

flow to the flowmeter maximum (50 g S.l). The pressure at which the condenser stabilises will

depend upon the water inlet temperawre.

(ii) Allow die unit to run for approximately IS minutes in order to reach a uniform operating

temperature. Then record die condenserpressmePc, evaporatorpressurePe' die condensing

temperature and die evaporating emperature ,.

(ill) ReducedIe cooling water flow by a small incrementso that dIe condenser ressure ncrease y

approximately

0-2CBcN

-z. This amountwill vary depending pon dIe coolingwater nlet

temperature.

Allow the unit to stabilise or a few minutesand again record the above parameters.

(iv) Re~ the procedureup to the maximumcondenser X'eSSureequiredor to the high pressure ut

out value of 22OkNm4

Typical resultsare shown n the table below.

Local Aunospheric~: lOlkN mol

PcI

kN

m-1 gaugeondenserressure

-31

-21

+4

+49

41 -11

CondenserPressure

PcI

kN m-1- bsolute

~ 70 80

90

105 150

Condensing

temperature

../~

15.0 19.5 24.0

27.0 31.0

41.0

P.I kN m°7. gauge

vaporatol' Pressure

-68 -69

-69 -69

-69 -69

32 32 32

vaporata Pressure

P

I

kN m4 absolute

33

32 32

Evaporating

temperature

.,/OC

6.S

4.0

4~

4.0 4.0

4.0


32/76

28

Note that tem~ have been estimated o d1enearestO.soC~ing die SIaOOardbenDOIDC1m

SUWIied. Whezc he opdoul temperature indicator is fitted ~~ may be ~ to d1e

nearestO.loC.

The resultsare ploUCd n graphical onn on Page29.

Note that the standard D'eSSUIeauge~y of tl % of gauge ull ..::a)e as beat shown as 00Ued

lines about a mean. The absolute :curacy of the dlermometersm-~(XIa} tem~ iDd-k.J1O 'nd

thmnocouples)plus readingerrors will also .sd to any disc~ies.


33/76

8

.

t

1

_

3

I

~

~

0

0

0

0

L

)

0

N

~

~

t

_

W

N

a

D

d

U

J

1

D

J

S

.

T

.

~

f

5

0

0

~

0

a

V

0

0


34/76

30

3.

DEMONSTRA ON OF "PUMPING OVER" OR "PUMPING DOWN" INTO mE

CONDENSER

Duringmaintenancef refrigemOOo Jaob.partkularly when repl-=ement f com~nb is involved.

it is convenient o transf~ the ~gerant to me conck.nser. This ba the ~vantage of saving me

refrigerant or f1D1her se and also may avoid the needof ev~ua1ionprior to rechargink.

In addition. or ecologicaleasonsollowingme guidelines f d1eMontreal l. ~ ventingof

refrigerants in manycountries owa criminaloffence.

This is a proc.edure ften used n indusbial and commercial efrigeration ~tise where the entire

refrigerant charge s condensed nd collected either in die corKlensertself or more commooiy in a

liquid receiver co~ted to the condenser. Once the chargebas beenplrDped nto the condenser r

liquid receiver hen work may be carriedout on the systemwidiout losing argequantitiesof refrigerant

to atmosphere.For ecological~ following die guidelinesof die Montteal Protorol, the venting

of refrigerant s in many countriesnow a criminal offence.

In the RefrigerationCycle Demonsb'81ion nit R633 d1ecoOOe~ and iquid receiver are combined

in d1esameglass cylinder.

In order o carry out pumping down, dIe unit should have beenoperatingnormally for ~veral minutes

widt an evaporatorand condenser ooling water flow rate of approximately40 gS.I.

By setting me ball valves as shown in me Refrigerant

Pump Down mode (~ Fig1De 2

- Page2), me

flow of condensediquid from the

expansion alve

at the ~ of the conoonSel:s

~

and iquid

will thereforecontinue o colle(:t n me condenser hamber.

As liquid ttansfecs rom the evapcnror, the level will fall and ess of the evaporaur coil surf~ will

be effective n evaporaling he liquid. The evaporatioo ate will reduceand die processwill become

slower. This effect may be offset as the liquid level becomes ery low by opening ONLY) the baD

valve at the baseof the evaporaU>r.

This will have the effect of utilising die capillary surface area and ambient air temperawre to eVa(X)rate

additiona1liquid.

If, beforepumping down, the unit basbeenoperated or a prolmged period, die liquid collectedat d1e

baseof the evaporaUX' ay appear hicker and less viscoos. It may also appear slightly yellow in

colour. The liquid remaining n die eva X)rators primarily the oil d1athas been carried over in die

form of mist and refrigerant oil mixture from the com~.

The oil will not evaporateat die pessures .:hieved by d1ecanpressor and tOOreforet must be

physically rewmed to die compressor asing.

Note that the unit should ~ SHUT DOWN when the refrigerant charge is in the PUMP DOWN

condition as under certain ambient conditions it is possible for die charge to migrate to the compreS&:Jr

casing.

~:

In an industrial plant, isolating valves are usually fitted between all major components. As ~

as the refrigerant has been b'ansferred to the condenser (or liquid receiver) the valves may be

closed. trapping the liquid. The defective comlX>nentcan dIeD be serviced or repJ.lK:edwid¥>Ut

losing the refrigerant charge.

At me end of the demonsb'8tionhe opportunity may be taken o reblrn the oil collected n the baseof

me evaporator o die condenser.The procedure or this is given underOil Return on Page 17.

However, f oil is not to be returned o the compressor t this stage,~ mIl valves should be set for

normal operation (SeeFigwe 2, Page2) and me refrigerant allowed o rewrn to the evaporator.


35/76

31

4.

DEMONSTRATION OF CHARGING

Due to die restrictions of die Montreal Protocol t is not recommended 1at he refrigerant charge s

removed rom the machine or any ~n other than essential epair.

If charge emoval s necessary 1en echargingmay be "demonstrated"f convenient o 00 so.

Charging rom a Hilton suppliedone nip can should ollow the Chargingor Recharging X'OCeduren

Page21.

Note that any refrigerant emoved rom the machine shouldbe stored n a screw topped metal can to

prevent evaporationand to stop moistme being absorbedby the oil in solution.

Any refrigerantstored n sucha can may be drawn ~k into the evaporator y connecting he charging

line to the charging valve in a similar way to the standard hargingprocedurebut then mmersing he

open end in the liquid inside the container. If the unit is turned on for normal operation then the

pressuredrop in the evaporatorwill cause he refrigerant o flow into the evaporator. Note that air is

likely to need venting from the condenser.


36/76

32

s.

DEMONSTRA nON OF mE EFFECT OF AIR IN A REFRIGERA nON SYSTEM

When air is present n a refrig~oo plant. t will O(X'Inally e swept rom the evaporata by me flow

of refrigerant vapourand will become tapped n the con(k;D.W'.

For a combinationof reasons.he air will ~ the com~ delivery IX'CSSIJreo rise. reducing die

coefficient of peifonnance.arxl increasing he power input for a given duty.

The ilx:reaseof pressures due to

(i)

The total pressure in the coodensu is approximately equal to die sum of the refrigeJ'aDtsatumtion

pressure~ the pressure of die air Jl'CseDt Dalton's Law of partial pressures).

and

(ii) The air tends o be swept towards die heat transfer surfaces. onning an insuJating ayer which

reduces~ heat b'ansfer oefficient. This in Ulm drives up die temperature ifference equjred

for a given heat ransfer ate and this results n a higher refrigerant sabJratiooemperature nd

pressure.

The effect of air in the systemmay be demonsttated s follows:

Procedure:

(i) Start the unit for normal operation and adjust the evaJX)ratorcooling water flow rate so dlat the

evaporator pressure is below abnospheric pressure. Unless the cooling water temperablre is v«y

high this is likely to be the case in all conditions.

Ensure that the unit is free of air and if o«.essary follow the air vendng procedtDe shown 00 Page

18.

(ii) Run the lmit for ~veral minutes n order to reachnormal operating emperattD'es en record all

system emperatures, essures and flow rates. Also visually note the condensationate on

me

corKlenser ooling coils.

(ill) Connect he angl~ endof the charging ire (C45/2)supplied n the ~es kit to the charging

valve at the baseof the evaporator.

(iv) Observe ~ evapc:ntor pressuregauge and ~ open the ball valve at the base of me

evaporator. The evaporatorpressuregaugewill indicate an increase n JXessureollowed by a

return to its original value.

The condenser ressure auge,however,will increaseand remain at the new value.

(v) Re~ openingof d1eball valve until the condenser Xessureasapproximatelydoubled rom its

original val~. Note that f the condenser esswe ~~ 22OkNmo1hen me high presswecut

out will operateand the experimentwill have o be repeated ran an air free conditioo.

When air is admitted 10 he evaj)(X'a1Ort initially adds 10 the pressure within the evaporator ~cording

10 Daltoo's Law. However it is almost immediately swept dlrough into die comlX'eSSOf y the flow of

refrigezant v8lX>ur. The mixbD'e then passesdlrougb 10 he comJX'CSSOrm ultimately to die condenser

where it can go no further d~ to the liquid at die base of the condenser.

In addition. the conlinuous flow of refrigerant vapoW' owards the condenser cooling coil causes die air

to remain around the coil region. The reduced rate of cooOOnsation hould be observed as well as die

increase in condenser pressure.

Record aU system temperatures. pessures and flow rates.

Typical resultsare shown n the following table.


37/76

33

Local AtmosphericPressure: OlkN m-1

1 Air Free

1. With Air

est No.

-69

-66

vaporala GaugePressure

p ~ I kN mo2

p ~ I kN mo2

35'2

bsolute EvaporatorPressure

400

5.5

t,/OC

m.1 g S.l

~/OC

~/OC

Po1

N

m-2

Pol kN m-2

r./OC

IDa

1 g S.l

t./OC

Evaporating emperature

20.0

20.0

vaporatorwateJ' low

11.0

1.0

vapora1fX water inlet

9.5

10.0

vapora1(X'water outlet

59

21

ondenser Gauge Pressure

80

160

bsolute Condenser Pressure

30.5

5.5

CondensingTemperature

4.0

.0

ondenserwater flow

12.0

2.0

ondenserwater inlet

22.0

20.3

t,/OC

ondenserwater outlet

The results are plotted on a

temperabJre-pressuregraph on Page 34.


38/76

3

0 »

2

.

» : =

=

~

t

D

a

=

t

D

.

~ 2

.

t

D

~

0

~

~

~

C

8

D

.

C (

J

(

J

c

.

C

<

G

Q

C

c

3

(

Q

C

C

C

>

(

Q

(

c

~

.

C

~

A

'

<

C

-

0

Q

~

O

.

+

0

I

~

.

J

o

~

-

-

n

C

c

-

n

=

W

.

(

:

A

Q

-

~

C

0

m

2


39/76

35

6.

EFFECT OF EVAPORATING AND CONDENSING TEMPERA ON THE

REFRIGERA ON RATE AND CONDENSER EAT OUTPUT

The effect of evaporating emperatmeon die refrigeration rate can be investigated.but due to d1e

limited effect on evaporating emperature f all but very argechangesn cooling water low it is more

graphic to investigatecondensing emperature irst.

If time pennits. the corresponding ffects of evaporating emperaturemay then be investigated.

The effect of increasingme condensing emperature n many refrigeration systemsand heat pwnps s

a reduction n me heat discharged rom me condenser nd in many casesa smaller reduction n the

refrigerating effect at the evaporator.

Similar reductionswill be observed f the evaporating emperatures lowered

The effocts are due pimarily to the reduction in volwnetric efficiency of the compressorat high

pressure atios (P

JP

and the reduction n specific volume of the refrigerant gas as the evaporating

temperature educes.

An investigationof die effects of pressure atio are given in the following experiment

A simple explanation or this is that for eachsuction strokeof die compressor lower massof gas for

the samevolume) s drawn in to the cylinder to be compressed.

The effect of increasingcondenser ressuremay be investigated n the following manner.

Once air free increase he condenser ooling water flow to the flowmeter maximum (50 g S.l).

The pressureat which the condenser tabiliseswill dependupon the water inlet temperature.

(ii) Set die evaporator water flow to approximately 20-30 g S'l and allow the unit to run for

approx,irnately 5-20 minutes. The time taken to stabilisewill dependupon the local ambient

conditions and the cooling water nlet temperature.

(ill) Record all the systemparameters s illustrated n the table on Page 36.

(iv) Reduce the condenser cooling water flow rate until the condenser pressure ncreasesby

approximately5-10 kN mo1,Allow the unit to stabiliseand again ecord the parameters n Page

36.

(v) Repeat or increasing ondenser ressureso dIe minimum readable alue on dIe condenserwater

flowmeter is ~bed, or the condenser ressure eaches 00 kN roo"gaugepressure.


40/76

36

OBSERVA nONS

Local AtmosphericPresswe: OlkN m-2

Test No.

1

2

:t

4 5

Pel kN m-2

Pel kN m-2

t,/OC

Evaporaux'GaugePressure

-68 -69 -69 -69 -69

32 32

32

32bsoluteEvaporalOr Pressme

33

6.5

4.0

4.0

4.0

4.0

V8IXX8UX' Temperature

di./ gin S.l

it/OC

20

20

20

20

vaporaUX'Water Row Ra&e

20

11.0 IJ.,O 11.0

11.0

vapor8tcrWater InJet Temp.

11.0

10

It)

IG

10

vaporat(X'Water Outlet Temp.

ft/1IC

../IIC

P./ tN m-2-

P./ tN m-2-

t,/1IC

10

Condensed iquid Temp.

Condenser Gauge Pressure -41

.31

-21 -II 4

70 80 90 105

bsoluteCondenser Pressure

60

CompressorDischargeTemp.

- - - -

r./OC

m./ gin S*l

15.0

J9.5

24,0

27.0 31.0

ondenser Temperawre

Condenser W &tel' Flow Rate

50.0

10.0

4.0

2.0

1.0

11,0

11.0

ondenserWater Inlet Temp.

r./ac

11.0

11.0

11.0

26.5

31.5

ondenser Water Outlet Temp.

r,/1:C

12.0

16.5

22.0

W/Waus

ompressorPower nput

Note d1a1he temperatures ecorded have been estimated o the nearest0.5°C using die standard

thennometerSupplied. If the optional temperature indicator is fitted with the hermocouple ensors

then the temperaturesmay be recorded o the nearestO.l°C.


41/76

37

SPECIMEN CALCULA nONS FOR TFST NO.2

EVAPORATOR

Rate of Heat Transfer to Water in EvaJX)rator:


42/76


43/76

39

7. ~GA nON OF THE EFFECTOF COMPRESSORRESSURE Ano ON SYSTEM

PERFORMANCE

The effect of increasing he condensing emperatureor a constantgiven evaporating emperatures to

increase he compression atio PJP. that the compressors required o deliver.

Due to die effects of valves and die necessarypiston to cylinder bead clearancesdie volumetric

efficiency of reciprocatingcompresSOISends o fall with increasingpressure atio.

Volumetric efficiency

=Actual Volume Delivered

CompressorSwept Volume

In terms of a refrigeration system.

Volumebic efficiency

=

Mass low of refris:erant Soecific volume of refris:erantat inlet

CompressorSwept Volume

Hence f dte volurneb'icefficiency falls widt increasing ressure atio then he effect will be a reduction

in the effective mass low of refrigerant. The mass low of refrigerant hrough he compressor elates

directly to dte amount condensingon the condensa- oil and this in turn relates to the rate of heat

b'ansfer o dte cooling water.

In addition me above equation ndicatesme effect of reducing me specific volume of the refrigerant

entering me compressor y lowering me evaporating emperature.

The effect of pressure ratio on system performance may be investigated by the following method which

is identical to that used in Experiment 6 on Page 35.

Once air free increase the condenser cooling water flow to the flowmeter maximum (50 g S.l). The

pressure at which the condenser stabilises will depend ulX>n he water inlet temperature.

(ii) Set he evaporatorwater low to approximately30 g S.land allow the unit to run for approximately

15-20minutes. The time taken o stabilisewill dependupon he ocal ambientconditionsand he

cooling water inlet temperature.

(ill) Record all the systemparameters s llustrated n the table on Page40.

(iv) Reduce the condenser cooling water flow rate until the condenser pressure ncreasesby

aP{X"Oximately-10 kN mol. Allow the unit to stabiliseand again record he parameters n Page

40.

(v) Re~ for increasingcondenser ressuresD he minimum readable alue on the condenserwater

flowmeter s reached,or the condenser ressure eaches200 kN m-zgaugepressure.


44/76

40

OBSERVA nONS

Local Atmospheric Preaure: 101 kN m4

3

s

est No.

1 1.

4

-69

68 -69 -69

-69

vapoI31a'GaugePressID'e

33

32 32

32

32

bsolute Evaporator Pressure

4.0

Pel tN m-2

Pe tN m-2

t,/OC

Ih. I gin S.l

it/OC

6-"' 4.0

4.0

4.0

vaponI(X'Tem~

20

20

20 20

20

vapora1aWater Row Rate

11.0

vaporaf« Waf.« InJetTemp.

11.0 11.0

11,0

11.0

10 10

10

10

vaporalakWater Outlet Temp.

ta/-C

10


re/OC

p.1 tN m-2

p.1 tN m-2

r.,/OC

-41

-31

-21

-11

4

ondenser Gauge Pressure

70

8C

90

IOS

bsoluteCondensezsure

60

Cu.u~~ Discharge emp

24.0

27.0

31.0

ondenserTmnpelabJre

../OC

di./ lID Sol

15.0

19.5

2.0

1.0

ondenser Watel' Row Rate 50.0 10.0 4.0

11.0

./OC

11,0

11.0 11.0

11.0ondenserWater Inlet Temp

22.0

26.5

31.5

ondenserWater Outlet Temp

's/OC

12.0 16.5

CompressorPower Input

W I Watts

Note that the temperatures ecorded have been estimated o the nearestO.5°C using the standard

thermometers upplied. If the optional temperature indicator is fitted with the thermocouple ensors

then the tempe~ may be recorded o the nearestO.I°C.


45/76

41

SPECIMENCALCULAnONS FOR T~T NO.3

EVAPORATOR

Rate of Heat Transfer to Water in EvaJX)rator:

Q.

=

iii. C, (11

~

Q.

. 20.0

X

10-3 4.18

X 10'X

(11.0- 10.0)W

Q = I3..6W

. -

CONDENSER

Rate of Heat Transfer to Water in Condenser:

Qc

= "c C, (r, - tJ

Qc = 4.0

x 10-' x 4.18 x 10' x (12.0 - 11.0)W

Q =18.3..2W

-

COMP~_SDR

Note that dIe pressmemtio shouldbe derived using Absolute pres8W'e ot GaugePressures.

Delivered PressureRatio

=Pc/P.

32/80

= 2.5

-

DERIVED RESULTS

CompressorPressmeRatio

p./p.

Q./W

Q./W

1.82 2.19

2.5

2.81

3.28

83.6 83.6

83.6

3.6 83.6

eat Transfer n Evaporator

229.9 183.9

129.6 85.7

eat Transfer n Condenser 200

These esults are presented raphically on Page42.

In order to investigatevolwneuic efficiency it would be necessaryo measure he rotational speedof

the compress


46/76


47/76

43

8.

DE~ATlON OF OVERALL HEAT TRANSFER BETWEEN R141b AND WATER

IN mE EV APORA TOR AND CONDENSER

The Overall Heat TransferCoefficient (U) is die heat tansfer ate per unit areaof heat tansfer surface

when a temperature ifferenceof ooe degreeexists betweendie hot and cold fluids.

In die evaporator,die refrigerant emperatures sensiblyconstant,but die water temperaturealls as t

passes hrough the coils. In die condenser omedegreeof superheating be presentwhen the gas

enters he condenser lass chamber. However the quantity of heat delivered due to the superheating

will be small relative to that attributable o the condensingphasechange. Examination of the high

pressure ine of the cycle diagram generatedn ExperimentNo.9 on Page47 will confirm this.

In oroor to analyse he overall heatb'aIlSfer oefficient a representativeemperature ifferencemust be

determined hat representshe driving force for heat ransferbetween he refrigerant and the water.

The temperature ifference o be used n this case s the "Logarithmic Mean" which is given by

where9... = Temperawre

ifferencebetweendie two fluids at inlet,

and 9..-1ot Temperatureifference etween ie two fluids at outlet.

A dleoreticalanalysisof dle logarithmic mean emperatme ifferencemay be found in most ext books

on heat transfer and will not dlereforebe expanded n dlis manual.

Once air free increasedie condenser ooling water flow to a mid range value.

which the condenser tabiliseswill dependupon the water nlet temperature.

The pressure t

(ii) Set the evaporatorwater flow to a mid range value and allow the unit to run for approximately

15-20minutes. The time taken o stabilisewill depend pon he ocal ambient conditionsand he


(ill) Record allllie systemparameters s llustrated n the table on Page44.


48/76

44

OBSERVATIONS

Local AUDOspheric: lOlkN m.~

Test No.

1

2.

3

4

5

Evaporata GaugePressure

-68

Absolute EvaporatorPressure

33

Pel tN mea

p.1 kN mea

t,/OC

die I gin S.l

rs/OC

'a/OC

6.5

vaporata'Temperature

20

vaporaI« Waf« Flow Rate

11.0vaporata Water Inlet Temp.

EVaporaI« Water Outlet Temp. 10


"lac

p.1 tN m-2

p.1 tN m-2

CondenserGaugePressW'e

-41

AbsoluteCondenser

ro

Compreso Discharge Temp.

-

t,IOC

Condenser Tempelature

r-/OC

Ib./ gin 8"1

15.0

Condenser Water Flow Rate

so.o

CondenserWaf« Inlet Temp.

~/ac

11.0

CondenserWater Outlet Temp.

r,/OC

12.0

W I WatU

ompressor Power Input

Note that the tem~rabJres recorded have been estimated o me nearest0.5°C using me standard

mennometers upplied. If the optional temperature indicator is fitted with the themtocouple~nsors

then the temperaturesmay be recorded o the nearestO.I°C.


49/76

45

For the Evaoorator

RaICof Heat Transfer o Wata' in EvaJX)rator:

Q.

S

IN.

C, (t1- t,)

Q.

S

20.0x 10-' x 4.18x 10' x (11.0 10.0)W

Q :.83.6W

-

e~

- 11.0 6.5

e~ = 10.0 - 6.5 =

4.5 3.5

In~

3.5

8 .

-

~K

Q

U=A&:

u . ~~ '- , W.-2 g-l

3.6

u = ~ w..-2 '

For the Condenser

- -

Rare of Heat Transf~ to Water n Coode~

Q~ = *~ c, ("

-

tJ

Q~ - 50.0x 10-' x 4.18x 10' x (12.0 11.0)W

Q~ = . W

8~ . 15.0 12.0

8--

.

15.0 12.0 . 3.0K

4.0 - 3.0

ID~

3.0

8-

.

~K


50/76

46

Heat Transfer Rate

u=~

A8.

u .

u = ~ Wm-2K-l


51/76

47

9. GENERATION OF A REFRIGERATION CYCLE DIAGRAM ON A PRFSSURE-

ENTHALPY CHART

Note this procedure can ONLY be undertaken by the following detailed method with the optional

temperature indicator fitted to the R633 unit as the temperature of the refrigerant liquid in the

condenser s required for one state point on the cycle diagram. However the procedure may be

modified for use with the standard thermometer set. See Page 48.

The fitting JX'OCedUIeor the optional temperature ndicator kit, if not already fitted. is given in

Appendix A. Details of the kit are available rom P A. Hilton Ltd. or their local representative.

The vapour compression efrigeration cycle is of paramount mportance n tentls of food and drug

preservation,air conditioning, and heat pumps. In order to analyse he systemperformance n tentlS

of die diermodynamic ycle it is common or engineers o record systempressW'eSnd temperawres

and dien to plot the various statepoints on a pressure-enthalpyhart of the wm'king fluid.

The working fluid in me Hilton RefrigerationCycle DemonstrationUnit SeriesR633 is R141b. This

has me chemical name 1.1.-Dichloro-l-fluoroed1ane.

A pressure-enthalpyhart for this substances shown on Page55.

A detaileddescriptionof die variousparameters isplayedand obtainable rom pressure-endtalpyharts

will be found n most text books on thermodynamics nd thereforewill not be expandedupon n this

manual.

In order to plot a cycle diagram or the unit the following procedureshould be adopted.

Procedure:

(i) Start me unit fOf normal operation as shownon Page 15 and ensuredtat me unit is air free by

venting air from the condenser s describedunder air venting on Page 18.

Once air free increase he condenser ooling water flow to a mid range value. The pressureat

which the condenser tabiliseswill dependupon the water nlet temperature.

(ii) Set the evaporatorwater flow to a mid range value and allow the unit to run for approximately

15-20minutes. The time taken o stabilisewill dependupon the ocal ambientconditionsand the


(ill) Record all the systemparameters s llustrated n the table on Page49.

(iv) In order o demonsttatehat the cycle varies or different operatingconditions t is recommended

that die condenser ressures varied by adjusbnent f die condenser ooling water low rate. The

unit should be allowed to stabiliseand die systemparametersecorded.

The proceduremay also be repeated t different evaporating emperatures nd the resultsplotted

on a pressure-enthalpyhart as describedbelow.

The results rom die following table are shown plotted on PageSO.

The statepoints a. b and c on the diagram on Page50 are located n the following manner:-

Pointa is at the ntersectionf theevaporator

hamber pIeSSm-e . = 32 kN moz

absolute nd he

evaporatingemperature Is = 4.0OC.

i)

(ii) Point b is at the ntersectionof the compressor hamberpressurePG= 70 kN

m°2.absolute

and he


52/76

48

(ill) Point c is at the inte~tion of the compressor hambel' ressurePc= 70 kN m-1~lute and d1e

condensediquid tem~ r. = 19.5OC.

(iv) The expansion s assumedo be adiabaticand dtereforea ~ of constantenthalpymay be drawn

vertically oown from IK'int c to intersectwidt the evarxratnr presSUIeine Pc.

Considering he processes 1a1 re happening t eachSta1e oint in turn:-

(i)

At JX)inta die v8lX>urrtm die evaporBt« s drawn nto the compe.-,r and me pressures raised

from P. to Pc. It is evident rom die line of constantentropy ntersectingwith JX)inta (1.9 kJ kg-I

K-1) that die compession is not isentropic as die pressure ise is completed at an entropy of

aPJXQximately .92 kJ kg-l K-1. If required the isentropic efficiency of compressionmay be

evaluated.

(ii) The vapour eaving the com~ at point b is superheated s t is to the right of the saturated

vapour ine. The vapoorcools slightly in the pi~ to the condenser nd hen n the condenserk-

su~rl1eating and colxlensing ake p1a;:e t essentiallyconstantpressure.

(ill) At point c me liquid at die baseof me condenser s slightly sub cooled due to me effect of me

cooling water tempembirebeing below the saturation emperature f me conde~ chamber

pressure water tem~ 11.6 o 16.7OC.Sawration emperanue t Pc= 70 kN m-1= 21.7°C).

In addition ~me sub cooling in this unit arrangements addeddue to the expansionvalve being

physically attached o the condenser aseplate. The temperature rop causedby me expansion

conductsheat through me baseplate rom me condensediquid reducing he liquid temperature

furdler.

(iv) The JXessure rop causedby me expansionbrings me refrigerant nto the valX>ur 1iquid ixtm'e

region betweenme saturatediquid and satlD'8ted apour ines. The mixture of vapourand iquid

may be seen n the sight glassadj~t to the evaporator.

The liquid/vapom mixbJIemay be seen eturning o the evalJ(X'atOrhrough he fitting in the tOp

plate.

Note that mough me experimentmay only be carried out in the aOOve etail utilising the optional

temperaturendicator. statepoints a and b may be determired using the standard hermometerS.

The temperature f dIe conOOnsediquid may. however.be estimated rom dIe saturationpressuren

the condenserf it is assumed lere s no sub-


53/76

49

OBSERVAnONS

Local AttnospbericPressure: OlkN m-2

Test No.

1

2.

3

4 5

-69

vaporala GaugePressure

p. I kN m4

P. I kN m4

bsolute Evaporator Pressure

32

ts/OC

Ib.I gill S-l

it/OC

~/OC

../OC

Pc tN m-l

Pc tN m-l

4.0

va{X)ratCK emperature

20

vaporara Water Flow Rate

11.2

vapofata Water Inlet Temp

9.7

vaporata' Water Outlet Temp


19.5

-31

ondenser auge

70

bsolute Condenser Pressure

Compressor Discharge Temp.

t.,/OC

../OC

dlc / gin S.l

r,./OC

41.7

19.5

ondenser emperablre

10.0

ondenser Water Row Rate

11.6

ondenserWater Inlet Temp.

~/OC

W I Watts

16.7ondenser Water Outlet Temp.



54/76

'

0

n

=

C

1

~=-.

-

6

;

O

~

_

~=.

-

6

'

<

_

~c~

~

.

-

0

VV

0

V0

J

0

0"

0

~

:

~

~

:

r~

P

:

~

-

J

0

-

;

.

~

w

.

N

~

-

~

V

~

-

.

~

-

~~

f

~

-

1

»

~

m

~

~ ~

m

~

"

9.

~

i

;

~

0 0

0

-

§

'

c

8

~

I

"

'

~

\

-

-

0

0

0

C

'

w

~

i

~

'

o

;

t

o

t

1

~

~

I

N

*

-

~

~

0

,

~

1

~

"v

f

"

\

r

.

~

\

I

~

'

.

~

~

~ 1

-

,

"

.

:

~

~

1

v

1

1

'

"

~

-

~

"

.

\

~

N

V

O

~

-

w

~

V

O

0

-

0

\

1

0

~0

"

"

"

0

u0

~0

\

o

0

-

l

o


55/76

51

10. MEASUREMENT OF mE EFFECT OF CONDENSING TEMPERATURE ON

COMPRFSSOR POWER INPUT

Note his procedure an~ be undertakenby the followingmethodwith the ootionaldi2ital

wattmeter itted to the R633unit.

The fitting procedure or the optional wattmeter kit. if not already itted, is given in Appendix B.

Details of the kit are available rom P.A. Hilton Ltd. or meir local re~tative.

The vapourcompression efrigerationcycle s utilised n both refrigerationand heatpump awlications.

In a refrigeration situation he eff~t of high ambient emperaturewill be to both ~rease the loan on

the refrigeration system (due to heat eakage ntq the cold space hrough thennal insulation) and to

increase he condensing emperaturen order to reject heat rom the system.

In a heat pump application he useful heat rom the condenserwill be more easily utilised for heating

applications f rejected at a high temperature.

In bodl cases,ncreasing ie condensing

X'Cssure

esul~ in a greaterwork requirementor die

compresscx. In addition, die increased compression ratio will in most cases result in a reduction of

system efficiency due to a reduction in volumetric efficiency. This is due to die necessary clearance

required for compressor valve opening and machining tolerances. At die end of a compression stroke

this clearance value is COOStantut at high pressure will contain a higher mass of unb'ansferred gas dIaD

at low pressure.

In addition, due o commercial actors, he motors used n mostdomestic efrigerationcompressors ill

be of a relatively low elec1rlcal fficiency. Henceelec1rlcal esistance eatingeffects n the windings

will be relatively high under all operatingconditions.

Procedure:

(i) Start the unit as for normal operation as shown on Page 15 and ensure hat the unit is air free

by venting air from me condenser s describedunder air venting on Page 18.

Once air free increase he condenser ooling water flow to maximum (50 g/s). The pressureat

which the condenser tabiliseswill dependupon the water nlet temperatm'e.

(ii) Set the evaporatorwater flow to a mid range value and allow me unit to run for awroximately

15-20minutes. The time taken o stabilisewill dependupon he local ambientconditionsand me


(ill) Record dJecompressor ower nput shown OIl he digital wattmeterand the condensing ressure

Pcas illustrated n dJe able on Page52.

(For referencet is recommendedhat students arefully touch he compressor asing o experience

the heat loss from die compressordue to electrical heating effects. This represents lectrical

energy wasted by the system. Care should be exerc~ed as the comoressor casioa will be

QI.)

(iv) Adjust the condenser ooling water low to a lower value and againallow the system o stabilise.

Re~ d1eabove observations.

(v) The proceduremay be repeatedup to the maximum condensing ressure f local cooling water

conditions permit


56/76

S2

OBSERVAnONS

kNmo2

ocal AtmosphericPressure:

5est No.

1

1

3

4

E

aporala

Gauge re~

Absolute Evaporator Pressure

Evaporata T~penIuIC

Pel tN mol

Pel tN mol

"/OC

Ih. I lID 8-1

ts/OC

E Vaporatm' Watrl' Row Rate

-

Evaporara Wat« In1etTemp.

EvaporaIO'Waf« Outlet Temp.

~/OC


"/OC

p./tN m4

p./tN m4

",/OC

CondenserGaugePreaure

15

190

Absolute Condenser Pressure

Compressor Discharge Temp.

- -

,,/oc

Ib./ gin S'1

~/OC

Condenser T emperahlre

Condenser Water Flow Rate

Condenser Water Inlet Temp.

CondenserWater Outlet Temp

r,/OC

Compressor Power Input

W I Watts

274

302

Note that the val~ observedwill dependupon the local conditions, he p-essures et and the local

supply voltage and frequerx:y.

As indicated above, he power required o drive the com~ increases s ~ condensing ressme

is increased.


57/76

S3

OBSERVAnONS

kNm-7.

ocal Atmospheric~:

5

2 3

4

est No.

Evaporata' GaugePressure

Absolute EvaporatorPressme

Pel kN m-2

p.1 kN m-2

.,/OC

m. I gin S-1

"/OC

t,/OC

r./OC

p~ kN m-2

p~ kN m-2

t.,/OC

~/OC

Ib.I gin S.1

r./OC

t,/OC

Evaporat(X'Temperature

Evapotat(X'Water Flow Rate

EvaporatorWater Inlet Temp.

EvaporatorWater Outlet Temp

Condensed iquid Temp-

Condenser Gauge Pressure

Absolute Condenser Pressure

Compres~ DischargeTemp.

Condenseremperawre

CondenserWater Flow Rate

CondenserWater Inlet Temp

CondenserWater Outlet Temp


W / Watts


58/76

n

~

.

~

.

=

3

t

D

a

~

~

~

~

.0 m

t

n

0

~

(

a

0

~

-

m

m

n

1

T

n

+

t

1

L

+

r


59/76

~

0

0

n

'

o

0

0

0

1

'

1

0

n

-

0

<

>

I

N 0 0~

0

0

\

O

~

~

0

.

-

~

~

0N

\

8

3

1

~

d

X

'

S

J

~

i

~

I

~

~

.

a

"

I

-

0

~

O

q

M

~

\

.

-

v

3

R

o

Q

U

S

3

N

-

~

-

0

0

0

0

~

0

-

0

)

-~

o

V

-

~

c

".

c

-

O0~

.

".

c

-

0

V

~

~

0

1

0

V

0

-

g

0N


60/76

S6

SPECIFIC RISKS

.

Contact with liquid will causesevere rost bite

.

Decomposesn a fire to give toxic and corrosive fumes

.

Containen may bunt if overheated

.

Risk of asphyxiation at high concentration

IDENI1F1Ct770N

SYDOBymS

1.

LI

l,l,-Dichloru-l-O=roethaDe. R-141

Uses

Plastic fOim blowing aaalt,SOlveDt

.1

1717-00-6

404-080-1

CAS

EINCS

OMPOSmON (.rubstanCeJ r impurities giving a hazard)

Substance 1 I ,-dichloro-l-Qooroethane

Impurida DOne

2.

PHYSIC4LPROPERTIES

At 2G-C liquid

3.

colo1U': colourless

0d01U': slightly etherial

3.1

PbysicalSUte

Health & Safety

Data Sheet

elting point: -lO3.S-C boiliDl point: 32.0-C

critical taDper8ture: 20S.C

~tiOD ~.1Ure: SOO-C

3.2

Tempentura

pH

DCutr81

.J

Solubility

.4

in ~ at 20.C: 0.54% y weight

in solvCDts: misciblewith aliphatic ydrocarbons.

aromatlcs,ketoaes.chkwiDated

derivatives 1¥i

If this material s redistributedo

sale,detailsof its hazards nd

recommendedmethods f safe

handlingshouldbe passed n to

users.

at SO.C:

.83 Ir

t 2Q8C: 0.81 bar

.5

Vapour pressure

1.24 ,cm)

5.011Ifm)

(liquid) at 2S.C:

(vlpOur) at 32.C:

3.6

Deasity

3.7

Other data

criticalpressure: 43.4bar

4.

4.1

STORAGE AND HANDLING

Spedal torace Dd Store etWeeI1- andSO-Cn a well v~rilated~

baDdUacrecaadoDS ~t storedn.sp«ial1y einforcednDDS.

PacklDgmaterials

.%

A void alloys with 2% or more of magnesium r

aluminium.Avoid plastics. Usesteelor polyethyleue

dr1Dns.

Stableat ambient emperabl1'e,ut willlDfcrlo thermal

decomposition t elevated emper8tureso give off

hydrochloricand hydrofllWric acidsaDdpossiblypbol8~

4.3

DecompolltioD prvducu

HRP Refrigerants Ltd.

Gellibirion Industrial Estate

Pontypridd

Mid Glamorgan

CF37 5SX

DaQcroas reacdODS

Withnaked ameor hot metal~

.4

4.5

lDdJvtduaJ meDdoD

and pAtecd"e measures

Gloya loula r=ommeadedvoidiquid

oDtKt

with kiD eyesDdheDh8Iati~f~.

In case of emergency elephone

Va1ri1arche workiD&area. No aom,. No aaked

nama.

4.6

Sped" protecdve

mcuara

01443 842255

If in m ~loscd -rea. YCDn18le or WaI' tt:1 oCOaIaiDCd

bratbiDI

~ (risk or -.hyxi8lioa/llK)xia).Allow

to eT8pOrIIc r pump nto salecoatIiIICr. Prevalt. rom

mtailla ~ bucmCUIS tc.

4.7

Meuara after IpWqe

0 Ieak8Ie


61/76

57

SPECIFIC RISKS

. Contact with liquid will causesevere rost bite

.

Decomposesn a fire to give toxic and corrosive fumes

. Containers may burst if overheated

. Risk of asphyxiation at high concentration

...8

Ret\un to supplia-.

estnacttoD of

coDtamiDated coDwDer

Store at a tanperaturebelow SO-C n a y~latM area,

away from all ~~ of heat or ignition.

Other recommeDdatioDS

.9

CAS

EINCS

1717-00

404-080

IGN1110N AND EXPLOSION

F1ashoiDt none

5.

5.1

5.1

Auto-ignition temperature none

Non-flammableproduct Thermal decomposition ives off

toxic fumesoChydrochloricand hydrofluoric acids and

phosgene.

Special ire or explosioD

hazards

S.J

Health & Safet

Data Sheet

ot applicable

.4

Extinction

Wear self-contained reathingapparatus nd ull acid

resistantprotectiveclothing.

5.5

Particularmeasura

during OR-fighting

Protect. ontainers rom heat~urces. Cool with water to

avoid ov« pressurisation.EDsure roductdoesnot come

into contactwith naked lamesor hot metal surfaces.

5.,

Other recommendations

If this material s redistribute

sale,detailsof its hazards nd

recommendedmethodsof saf

handlingshouldbe passed n

users.

6.

TOXlCOLOGICtL NFORMATION

Employersshouldbe aware hat this product s ~lvent

abusable.

Vapour

2,500 ppm for 30-60minuteswin cause ertigo,

drowsiness nd respiratoryproblems. May cause ncreased

sensitivity of myocardiumabove 12,500 pm.

Uquid

Repeated nd proloaaedskin contactwill produce

dermatosis. Eye contactwill lead to irritation. redness nd

moderate onjunctivitus.

7.

HRP Refrigerants Ltd.

Gellihirion Industrial Estat

Pontypridd

Mid Glamorgan

CF37 5SX

FIRST AID PROCEDURES

Skin contact Washwith copious molmts fwater'.

Inhalation Removeo fresh ir. ApplyoxygenCbreathings

difficult. Consult doctor.

EyeCODtact Wash DQ .~a~elyith copious molmts f water.

Consult an opbtbalmologist.

8.

In caseof emergencyelepho

SPECIAL PRECt U110NS FOR WASTEDISPOSAL

This matcria1s subj«t to the resttictioasof the

EnvironmentalProt=tiol1 Act and shouldoot be Va1ted o

atmosphere.W.. materialcan be ~ to HRPR.

Movancnt of refri&~ for ~1amation or destIuctioD s

subj~t to the Duty of Care lK requiIeIlppropt.ate

01443 842255


62/76


63/76

S9

1 2

'3

4

Amendments

2 MAINS FILTER ADDED

10.9.97 JB

A

NEW 3 CORE POWER CABLE

FROM TRANSFORMERSECONDARY

2'OV

TO MA~S FILTER

LENGTH 1000 mm

) LINE t

-0

)1

r---

j

.

1 I

.

1

I i: I

1

1

@}

~:

.

~I

...1

-


64/76


65/76

61

APPENDIX A

OP'nONAL DIGITAL TEMPERATURE INDICATOR

R633A

If£I-I"iNG INSTRUcnONS


66/76

62

--

--

VjQllK

mQJCatorl in the centre of the Wlit.

The addition of the digilal temJ'eraLure ndicator not only increases die resolutioo of tem})el3ture

measuremenm rom to.soC to O.IOC but a thennocouple sensor is provided to record the temlJeJ'a1Ures

of the iquid in the baseof the condenser

hamber re.

The addi iOnal teJnj el tures al w a compl te vap our comP ssi n cy l di gram to be nrn.i .~_ .. - 1

refrierant R41b PCssure-enthaIpy digram.

Once he level has been measured r marked,position the ball valves or shutdown (SeeFigure 2

-

R633 Valve Positions)and hJm he unit off. Turn off and disconnect he unit from the water supply.

Isolate the unit from its electrical supply and then remove

he bolts and one nut securing the rear

panel.

Store he bolts, nut and washersn a containeras thesewill be required or refitting the panel.

Remove he hermometersrom their pocketsand store hesesafely. Note hat f the original installation

recommendations ere ollowed dlere will be someoil in ~h of die dlennometer ockets.

With the help of an assistantay the machineon its back and ocate he 3mm (1/8") diameterblanking

rod in a pipe fitting in the 00seof the condenser hamber. This is the ocation or the

1s thennocouple.


67/76

63

Ensure mat the liquid level is below the level of the blanking rod and that the condenser ressure s

either at or below atmospheric pressure.

Using a close itting spanner emove he nut securingdIe blanking rod.

Take the 0 3mm x 8Smm long diennocouple ( MIS/IO) and using a 0 3mm compressionolive

(PF4/67) and die original nut. insert the diennocouple n die chamber o a depdi JUST BELOW that

of the measurediquid level.

Rewm me unit to an upright position. Thosewim accesso a vacuumpump may eXb'act ny air from

the systemby connecting o me internal pipe leading from me vent valve on top of the condenser

chamber.

Note that the oil in the unit is hygroscopic absorbswater vapour rom the air) and the unit shouldDOt

be left open o atmosphereor long periods.

Fit the 7 shon rod type thermocouplesIMlS/l6) in placeof the original thermometers.For the present

time the thermocouple onnecting eadscan be left ttailing at the front of the panel.

Remove die 92mm x 92mm blank insttument case from the panel by releasing die retaining screws from

inside die machine panel and withdrawing die case from die front of the unit.

The digital temperatw'endicator and multi way selecta-switch are two separatetems. A separate

core bennocoupleable s suppliedo makeme ink betweenmemo

FirSt nstall the 10 way selector ]MIS/50) at the bottom of the 92mm x 92mm panel orifice. This is

retained y wire springs ndclips whichpress gainsthe ascia. Refer o FigureA on Page 5.

The indicator ( MIS/53) is fitted above he multi way selectorand retainedby jacking screwswhich

bear on me rear of the panel fascia. Refer to Figure B on Page65.

Make the 2 core thermocouple onnection n accordancewith the wiring diagram on Page71

The Brown or Green (+) wire runs from COMM I to indicator terminal 25 "VI".

The Blue or White (-) wire runs from the terminal on die right of COMM 1 to indicator ternrinal26

"COM",

Apply the label "Oc" to the fa:e of the indicator to the right of the digital display.

Apply the yellow label "TemperattJrendicator" to the panel fascia.

Electrical Installation

The 3 core IX>wer upply lead for die optional ternperattJrendicator and separate ptional wawneter

is factory fitted to the following tenninalson the DIN rail connectors n the right handside of die unit

adjacent o the input IX>weread. Their free endsare dentified ~ follows:

49 (Eard1

-ColourGreen Yellow suipe) FromDIN Rail 5

47 (Line -Colour Red) From DIN Rail 8

48 (NeuU'al

-

Colour Black) From DIN Rail 13

~ units already itted widt a wattmeter (R633B) will use the ~k. of loose JinkssuWlied to tap

into the wattmeter K>wer upply. Refer to the wiring diagramon Page71.

Units not fitted wim me wattmeterwill useme free wires abelled 7 (Line

-

Cololn' Red) and 48

(Neub'al

-

Colour Black) directly.


68/76

64

The free end of d1e ead will havebeenprotectedwith tenninal covers. Theseshooldbe removedand

the 3 wires given 1 turn throughme ferrite ring suppliedand ~1Ued ooar o the ndicator. The red and

b1a;k cablesshooldbe connected o the following terDlinalson the digital temperatW'endicator. Note

that as ~ digital temper8bJrendicator s double nsulated. he green/yellowearth wire is not used n

this application.

18 L Line renninal securesRed wire 47

17 N N euttal terminal securesB1a:k wire 48

The themtocouple eadsmay now be ~red to the thennocoupleenninalson the multi way switch

oox. Note fran the wiring diagram on Page71 that ~h of the 10 switcOOdhannelcoonectioos n

the rear of the oox has4 terminals. However. n eachcaseonly the eft baOO air of eachgroup of four

areutilised.

Note that due o a new EuropeanStandard, ome ype K d1ennocoupie ~ will utilise brown andblue

insulation and od1ers reenand white to identify the polarity.

For ~b tbennocouple he brown or green~itive lead s connectedo the tenninal marked 1 in ~b

group of four. The blue or white negative ead connects o me next terminal on the RIGIrr of me

tenninal maIked 1 n eocbgroup of four. The remaining ennina1sn eachgroup of four are not used.

Note that only channels to 8 (CHI, CH2, aD...CH8) are utilised. The remainingchannels,9 and

0, are not utilised for dlis option kiL

Start with ~ merm


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6S

FIGURE A

PA~L

~

USE A SUITABLE FLAT

SCREWDRIVERTO PUSH AND

ROTATE THE ClP ONTO THE

TWO BRASS STUDS ON THE

SlOE OF THE SWITCH CASE.

THE OPPOSITE SVE

FITTED IN THE SAME

MANNER BUT INVERTED


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APPENDIX B

Refrigeration Cycle Demonstration Unit

Documents