Refrigeration

System Components
A Trane Air Conditioning Clinic

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Vapor-Compression Refrigeration

condenser

expansion
device
compressor

evaporator
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Refrigeration
System Components
period one
Refrigeration Cycle

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Refrigeration Cycle
pressure

A evaporator B

© American Standard Inc. 1999

enthalpy Air Conditioning Clinic TRG-TRC005-EN
Refrigeration Cycle

C
pressure

compressor

A evaporator B

© American Standard Inc. 1999

enthalpy Air Conditioning Clinic TRG-TRC005-EN
Refrigeration Cycle

D condenser C
pressure

compressor

A evaporator B

© American Standard Inc. 1999

enthalpy Air Conditioning Clinic TRG-TRC005-EN
Refrigeration Cycle

D condenser C
pressure

expansion
device compressor

A evaporator B

© American Standard Inc. 1999

enthalpy Air Conditioning Clinic TRG-TRC005-EN
Refrigeration
System Components
period two
Condensers

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Air-Cooled Condenser

propeller
fan

outdoor
air
condenser
coil
subcooler
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Effect of Subcooling

subcooling

C
D
{ DI
pressure

AI
A B
refrigeration
effect

© American Standard Inc. 1999

enthalpy Air Conditioning Clinic TRG-TRC005-EN
Centrifugal Fan Air-Cooled Condenser

condenser
coil

centrifugal
fan

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Evaporative Condenser

fan

refrigerant
vapor
condenser
coil

pump
sump
© American Standard Inc. 1999
liquid refrigerant subcooler Air Conditioning Clinic TRG-TRC005-EN
 Water-Cooled Condenser

hot, refrigerant vapor

95ºF
[35ºC]

cooling water

85ºF
[29ºC]
subcooler
subcooled, liquid
refrigerant

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Cooling Tower
propeller sprays
fan

fill

outdoor
air

sump
85ºF to from 95ºF
[29ºC] [35ºC]
© American Standard Inc. 1999
condenser condenser Air Conditioning Clinic TRG-TRC005-EN
Condenser Control
 Condenser capacity is influenced by:
 Temperature difference between refrigerant and
cooling media
 Flow rate of cooling media through condenser
 Flow rate of refrigerant through condenser

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Condenser Capacity
full load
condenser heat
rejection capacity
full load
pressure

part load part load

condenser heat
rejection capacity

© American Standard Inc. 1999

enthalpy Air Conditioning Clinic TRG-TRC005-EN
Condensing Temperature Control

flow-regulating
valve

condenser

condenser
water pump

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Vary Condenser Water Flow Rate

cooling tower cooling tower

condenser
diverting
variable-speed valve bypass pipe
drive
condenser
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
 Vary Entering Water Temperature
variable-
speed
drive
cooling tower
cooling tower

condenser

bypass pipe diverting

valve
condenser

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Cooling Tower Bypass

40ºF
[4ºC]
cooling tower
diverting
bypass pipe valve

55ºF 65ºF
[13ºC] [18ºC]

condenser

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

 Air-Cooled Condenser Control

damper

condenser airflow
A B
fan A

fan B
fan A

heat rejection capacity

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Condenser Flooding Control

condenser
B
C

A expansion
valve
liquid receiver
evaporator

discharge line
© American Standard Inc. 1999
compressor Air Conditioning Clinic TRG-TRC005-EN
Refrigeration
System Components
period three
Evaporators

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Finned-Tube Evaporator

liquid/vapor
refrigerant

airflow

refrigerant vapor

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Turbulent Flow

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Finned-Tube Evaporator
liquid/vapor
refrigerant

airflow

liquid
distributor

suction refrigerant vapor

header
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Superheat
B
A

B
A C

{
C superheat
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Shell-and-Tube Evaporator
chilled
water
supply chilled
baffles water
return

refrigerant
vapor
liquid/vapor
refrigerant
tube bundle
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Shell-and-Tube Evaporator

baffles

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Evaporator Control
 Evaporator capacity is influenced by:
 Temperature difference between refrigerant and air or
water being cooled
 Flow rate of air or water through evaporator
 Flow rate of refrigerant through evaporator

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Finned-Tube Evaporator Control

expansion
valve
evaporator

liquid
refrigerant

refrigerant
vapor

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Face-Split Arrangement
distributors

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Face-Split Arrangement

t iv e coil
inac 80ºF
[27ºC]

c oil 55ºF
ct i ve [13ºC]
a
80ºF
[27ºC]
30ºF
[-1.1ºC]

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Intertwined Arrangement

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Row-Split Arrangement

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Row-Split Arrangement
70ºF
[21ºC]

80ºF 55ºF
[27ºC] [13ºC]

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

 Shell-and-Tube Evaporator Control

shell-and-tube
evaporator

refrigerant
vapor

liquid
refrigerant expansion
valve
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Refrigeration
System Components
period four
Expansion Devices

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Expansion Device

D condenser C
pressure

expansion
device compressor

A evaporator B

© American Standard Inc. 1999

enthalpy Air Conditioning Clinic TRG-TRC005-EN
Thermostatic Expansion Valve

thermostatic
expansion
valve (TXV)

liquid
evaporator refrigerant
liquid/vapor
mixture

refrigerant
vapor
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
TXV Control

liquid
refrigerant
liquid/vapor
mixture
A

refrigerant
vapor

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

TXV Control

liquid
refrigerant

liquid/vapor
mixture

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Superheat
85 psia, 41ºF
[0.59 MPa, 5ºC]
TXV

liquid
refrigerant

290 psia, 109ºF

[2 MPa, 42.8ºC]

A
superheated
vapor
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
 Superheat
85 psia, 41ºF
[0.59 MPa, 5ºC]
TXV

290 psia, 109ºF

79 psia [2 MPa, 42.8ºC]
[0.54 MPa]
49ºF
[9.4ºC]

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

 TXV Operation

diaphragm
evaporator

spring
remote
bulb

suction
line external equalizer distributor
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
 TXV Operation
valve diaphragm
97 psia
[0.67 MPa]

49ºF spring
[94ºC]

79 psia 18 psi
79 psia [0.54 MPa] [0.13 MPa]
[0.54 MPa]
suction valve pin
line

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

TXV Operation

external equalizer
TXV

remote B A
bulb

© American Standard Inc. 1999 C Air Conditioning Clinic TRG-TRC005-EN

Superheat Setting
 Too little superheat:
 Risk of damage to compressor by liquid refrigerant

 Too much superheat:

 Reduction of system efficiency
 Potential of coil frosting
 Risk of compressor damage due to overheating

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Refrigeration
System Components
period five
Accessories

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Solenoid Valve

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Solenoid Valve

expansion
valve
finned-tube
evaporator

solenoid
valves

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Solenoid Valve

liquid line discharge

line
condenser

expansion
valve compressor
evaporator
suction
solenoid line
valve

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Liquid-Line Filter Drier

liquid line

liquid-line expansion
filter drier valve

solenoid
valve
© American Standard Inc. 1999
evaporator Air Conditioning Clinic TRG-TRC005-EN
Liquid-Line Filter Drier
replaceable
core type

core

sealed type
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Moisture-Indicating Sight Glass

liquid line

sight
expansion
glass
valve

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Suction Line Filter

suction
line filter compressor

suction
line

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Suction Line Filter
replaceable
core type

sealed type
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Hot Gas Muffler

discharge
reciprocating
compressor
line

hot gas
muffler

shell

© American Standard Inc. 1999 perforated tube Air Conditioning Clinic TRG-TRC005-EN
Shutoff Valve

shutoff
valve liquid line shutoff
valve
condenser

liquid-line
filter drier
evaporator
compressor

shutoff
valves
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Access Port

condenser
liquid line
access port

evaporator
compressor

suction line
access ports
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Refrigeration
System Components
period six
Review

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

Review—Period One

D condenser C
pressure

expansion
device compressor

A evaporator B

© American Standard Inc. 1999

enthalpy Air Conditioning Clinic TRG-TRC005-EN
Review—Period Two
evaporative
condenser

air-cooled
condenser

water-cooled
condenser
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Review—Period Three
finned-tube
evaporator

shell-and-tube
evaporator
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN
Review—Period Four

evaporator

TXV
remote
bulb

external equalizer

© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN

 Review—Period Five

shutoff
valve
access
condenser
port
suction
solenoid line filter
valve TXV
compressor
sight
liquid-line glass
filter drier
evaporator
© American Standard Inc. 1999 Air Conditioning Clinic TRG-TRC005-EN