ac and refrigeration plants

8/18/2019 AC and Refrigeration Plants

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RefrigerationRefrigeration

andandAir ConditioningAir Conditioning


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AC &R AC &R

ObjectivesObjectives

• Basic operationBasic operation

• Principle componentsPrinciple components

• Safety considerationsSafety considerations

• Thermodynamic principlesThermodynamic principles

• Determine output and efficiency ofDetermine output and efficiency ofrefrigeration systemsrefrigeration systems


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References References

• INEINE Ch 19 !"1#!$1% &&& don't read 19("% Ch 19 !"1#!$1% &&& don't read 19("%

• PNEPNE Ch )) 1 # 1*% Ch )) 1 # 1*%

• +,+,- .(/( 0))- .(/( 0))• Teap 2 !3(1)45Teap 2 !3(1)45

• Tcond 2 9!("45Tcond 2 9!("45


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Uses of AC&R SystemsUses of AC&R Systems

• Cooling of stores and cargoCooling of stores and cargo

• Cooling of electronic spaces and e6uipmentCooling of electronic spaces and e6uipment

7 CIC computers and consoles%CIC computers and consoles%

7 8adio communications gear%8adio communications gear%

7 8adars8adars

• Cooling of magainesCooling of magaines

• :ir conditioning for cre; comfort:ir conditioning for cre; comfort


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Definition Review Definition Review

• Specific heat Cp% 7 :mount of heat re6uired to raise the temperature of 1

pound of sunit%

• 8efrigeration # Cooling of an o


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Generic CycleGeneric Cycle


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Thermodynamic CycleThermodynamic Cycle


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Vaor!ComressionVaor!Comression

Refri"eration Cycle Refri"eration Cycle• 8efrigerant8efrigerant

• 8eceier 8eceier

• Thermostatic e@pansion ale TA%Thermostatic e@pansion ale TA%

• Eaporator Eaporator

• Compressor Compressor • Condenser Condenser


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Refri"eration Refri"eration CycleCycle


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Refri"erant Refri"erant

• ust hae the follo;ing propertiesust hae the follo;ing properties

7 +igh latent heat of aporiation # ma@ cooling+igh latent heat of aporiation # ma@ cooling

7 Non#to@icity # not a health haard Non#to@icity # not a health haard

7 Desira


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#$ansion #$ansion

• .i6uid 5reon enters the e@pansion ale at.i6uid 5reon enters the e@pansion ale at

high pressurehigh pressure

• 8efrigerant leaes TA at a much lo;er8efrigerant leaes TA at a much lo;er

pressure pressure

• :s pressure drops apor formation


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#vaoration #vaoration

• 5rom TA # 5reon is a saturated mi@ture of5rom TA # 5reon is a saturated mi@ture of

li6uid and apor li6uid and apor

• Cooling coil acts as a heat e@changer Cooling coil acts as a heat e@changer

• :


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ComressionComression

• .o; pressure superheated 5reon apor.o; pressure superheated 5reon apor

enters the suction side of the compressorenters the suction side of the compressor

• 8efrigerant is compressed from a lo;8efrigerant is compressed from a lo;

pressure apor to a high pressure apor pressure apor to a high pressure apor

• Increase in energy proides the driingIncrease in energy proides the driing

force to allo; the 5reon to flo; through theforce to allo; the 5reon to flo; through the

systemsystem


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CondensationCondensation

• 8efrigerant returned to starting point as a8efrigerant returned to starting point as a

high pressure=temperature su


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Receiver Receiver

• Temporary storage space and surge tan forTemporary storage space and surge tan for

the su


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Air Conditionin" Air Conditionin"

%rinciles of Oeration %rinciles of Oeration

• :ir Conditioning:ir Conditioning

7 aintaining the atmosphere of an enclosedaintaining the atmosphere of an enclosedspace at a re6uired temp humidity and purityspace at a re6uired temp humidity and purity

7 Cools = Dehumidifies air ia cooling coilsCools = Dehumidifies air ia cooling coils

;ithin entilation system;ithin entilation system 7 +eaters in entilation system+eaters in entilation system

7 +umidification units may


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Air Conditionin" Air Conditionin"

Systems Systems

• 8efrigerant circulating system8efrigerant circulating system

7 Directly cools cooling coilsDirectly cools cooling coils

• Chilled ;ater circulating systemChilled ;ater circulating system 7 8efrigeration system cools chill ;ater ;hich cools8efrigeration system cools chill ;ater ;hich cools

cooling coilscooling coils

• Self#Contained SystemSelf#Contained System

7 :dded on to ships ;hich originally did not hae :C plants:dded on to ships ;hich originally did not hae :C plants

7 Not located in entilation system ;indo; unit% Not located in entilation system ;indo; unit%


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asic AC System asic AC System'Chilled (ater Circ)lation*'Chilled (ater Circ)lation*


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S)mmary S)mmary

ac and refrigeration plants

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