Chapter 9 Refrigeration and Liquefaction Introduction 使物系的温度降到低于周围环境物质（如大气）的温度的过程称 为制冷过程。 冷冻温度高于100℃称普通冷冻（普冷），低于-100℃称为深度 冷冻（深冷） content 9.1 The Carnot Refrigerator 9.2 The Vapor-Compression Cycle 9.3 The Choice of Refrigerant 9.4 Absorption Refrigeration 9.5 The Heat Pump 9.6 Liquefaction Processes 9.1 The Carnot Refrigerator A refrigeration cycle is a reversed heat-engine cycle 音 3 condenser expander compressor 2 Evaporator
Chapter 9 Refrigeration and Liquefaction Introduction 使物系的温度降到低于周围环境物质(如大气)的温度的过程称 为制冷过程。 冷冻温度高于-100℃称普通冷冻（普冷），低于-100℃ 称为深度 冷冻（深冷） content 9.1 The Carnot Refrigerator 9.2 The Vapor-Compression Cycle 9.3 The Choice of Refrigerant 9.4 Absorption Refrigeration 9.5 The Heat Pump 9.6 Liquefaction Processes 9.1 The Carnot Refrigerator A refrigeration cycle is a reversed heat-engine cycle expander compressor 2 4 3 1 condenser Evaporator
TH Carnot refrigerator Tc Thinking(9-1) Refrigerant(制冷剂for the Carnot Refrigerator? Refrigerant(制冷剂) Four steps and TS diagram Reversible isothermal evaporation process Reversible isothermal condension process Reversible adiabatic expansion process Reversible adiabatic compression process ↑T S Coefficient of performance(效能系数制冷系数) heat absorbed at the lower temperature net work
Thinking(9-1) Refrigerant (制冷剂) for the Carnot Refrigerator ? Refrigerant (制冷剂) Four steps and TS diagram Reversible isothermal evaporation process Reversible isothermal condension process Reversible adiabatic expansion process Reversible adiabatic compression process Coefficient of performance (效能系数 制冷系数) heat absorbed at the lower temperature QC net work W = = TH TC QH QC W 2 4 3 1 T S TH Tc Carnot refrigerator refrigera tor
The cycle requires the addition of net work w=l№al-leal 岛受1经 T Review 2=T(S2-S) Te 1 0. S n=T(S;-S.) 9.2 The Vapor-compression Cycle Plant Evaporator Throttle valve Condenser Compressor
The cycle requires the addition of net work W Q Q = − H C 1 H C C W Q Q Q = − 1 H H C C C C W T T T Q T T − = − = Review QC 2 1 ( ) Q T S S C C = − QH 3 4 ( ) Q T S S H H = − 9.2 The Vapor-compression Cycle Plant Evaporator Throttle valve Condenser Compressor 2 4 3 1 T S TH Tc QC QH
condenser 3 Throttle valve compressor 2 evaporator Refrigerant (制冷剂 Four steps Isothermal evaporation process(1-2) Compression process(2-3) Cooled and condension process(3-4) Expansion process(4-1) 3 TS diagram Calculation: On the basis ofa unit mass of fluid
Refrigerant (制冷剂) Four steps Isothermal evaporation process (1→2) Compression process (2→3) Cooled and condension process (3→4 ) Expansion process (4→1) TS diagram Calculation： On the basis of a unit mass of fluid condenser 4 1 2 3 compressor Throttle valve evaporator S T 4 1 2 3
n=H3-H Qc=H,-H 0=4-月 H3-H2 Ws Hs-H2 The rate of circulation of refrigerant HH Ws=△H 4 0 c=△H TS diagram and pH diagram
Q H H H = − 3 4 Q H H C = − 2 1 2 1 3 2 H H H H − = − W H H S = − 3 2 The rate of circulation of refrigerant 2 1 QC m H H = − TS diagram and pH diagram S T 4 1 2 3 QH= △H QC=△H WS =△H