Post on 07-Jul-2018
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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