Refrigeration
36
Refrigeration Cycle
Transcript of Refrigeration
Refrigeration Cycle
10-1 Vapor-Compression Cycle
10-1-1 The Reversed Carnot Cycle10-1-1 The Reversed Carnot Cycle
w
qCOP L
c
14
14
ssTT
ssT
LH
L
LH
L
TT
T
T
s
4 1
23TH
TL
1
1
L
H
TT
Coefficient of Performance
Disadvantages
•Process 2-3 is difficult to be Fulfill in compressor
•Process 4-1 will do harm to turbine
10-1-2 The Ideal Vapor-Compression Refrigeration 10-1-2 The Ideal Vapor-Compression Refrigeration CycleCycle
condenser
Equipments:
1
2
3
4
compressor
Expansion valve
evaporator
T
s
TH
TL1
2
3
4
condenser
compressor
evaporator
Capillary tube
10-1-3 The COP of 10-1-3 The COP of Vapor-Compression Cycle
h-s diagram
h
s
1
2
34
Usually p1, p2 are available
h
s
1
2
34
From p1, get h1”, s1”
h1 = h1” s1 = s1”
From p2 , s1, get h2
From p2 , get h2’
h3= h2’
h4 = h3
w
qCOP L
12
41
hh
hh
p-h diagram
p
h
1
23
4
10-2 Refrigerant
•Ammonia
•CFC(chlorofluorocarbons)
•water
Good refrigerant
High enthalpy of vaporization
Not too low evaporator pressure
Not too high condenser pressure
Nontoxic
Noncorrosive
Chemically stable
Low cost
10-3 Heat Pump
An equipment Absorbing heat from environment for heating purpose
T
s
TH
T01
2
3
4
12
32
hh
hhCOPhp
Heat pump for heating
Heat pump for refrigeration
10-4 Innovative Vapor-compression Refrigeration Systems
10-4-1 Regenerative Vapor Compression cycle
EquipmentsEquipments
condenser
evaporator
Heat exchange
r
separator
compressor
T
s
TH
TL1
2
3
4
T-s DiagramT-s Diagram
2’
1’
10-4-2 Cascade Refrigeration Systems10-4-2 Cascade Refrigeration Systems
condenser
evaporator
T
s
T0
T-s DiagramT-s Diagram
10-4-3 Multistage Compression Refrigeration 10-4-3 Multistage Compression Refrigeration SystemsSystems
condenser
evaporator
Flash chamber
1
2
3
heat exchanger
45
6
7
8
9
T
s
1
2
3
4
5
67
8
9
10-4-4 Multipurpose Refrigeration Systems with a 10-4-4 Multipurpose Refrigeration Systems with a Single CompressorSingle Compressor
condenser
Freezer
refrigerator
1
2
3
4
5
6
Alternative path
T
s
1
2
3
4
5
10-4-5 Liquefaction of Gas10-4-5 Liquefaction of Gas
Heat exchanger
Make up gas
Liquid removed
Multistage compressor
1
2
3
4
5
T
s
1
2
1
3
45
10-5 Gas Refrigeration cycle
10-4-1 Equipments
Heat exchanger
QH
Heat exchanger
QL
compressor
turbine
T
s
p2
p1
1
2
3
4
T0
TL
10-4-2 COP of Gas Refrigeration Cycle
4132
41
hhhh
hhCOP
4132
41
TTTTC
TTC
p
p
1
1
41
32
TT
TT
T
s
1
2
3
4
T0
TL
k
k
T
T
T
T 1
4
3
1
2
1
2
41
32
T
T
TT
TT
1
1
1
2
TT
COP
T
s
1
2
3
4
T0
TL
1
11
k
k
Since 1
11
k
kCOP
•To decrease compression ratio can increase COP
•To To decrease compression ratio will decrease power ratio
T
s
T0
TL
T
s
T0
TL
1
2
4
5
3
q
6
q
10-4-3 Regenerative Gas Refrigeration Cycle
Heat exchanger
QH
Heat exchanger
QL
compressor
turbine
regenerator
1 2
34 5
6
10-6 Absorption Refrigeration System
heat
condenser
evaporator
=compressor
Refrigerant: Ammonia
Transport medium: Water
Refrigerant: Water
Transport medium: Lithium bromide
10-6 Adsorption Refrigeration
Solar energy
Active carbon
evaporator
condenser
Cooling Tube
Solar energyNight
Cold air
Active carbon
Vacuum tubeCooling tower
The End of This Chapter
Thank You
