period one
Types of Water Chillers
notes
Vapor-Compression Cycle
| reject heat | |
D | | C |
| condenser | compressor |
expansion | |
| |
device | | energyin |
| |
A | evaporator | B |
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| absorbheat | Figure 5 |
| |
Vapor-Compression Water Chillers
In the vapor-compression refrigeration cycle, refrigerant enters the evaporator in the form of a cool, low-pressure mixture of liquid and vapor (A). Heat is transferred from the relatively-warm air or water to the refrigerant, causing the liquid refrigerant to boil. The resulting vapor (B) is then drawn from the evaporator by the compressor, which increases the pressure and temperature of the refrigerant vapor.
The hot, high-pressure refrigerant vapor (C) leaving the compressor enters the condenser, where heat is transferred to ambient air or water at a lower temperature. Inside the condenser, the refrigerant vapor condenses into a liquid. This liquid refrigerant (D) then flows to the expansion device, which creates a pressure drop that reduces the pressure of the refrigerant to that of the evaporator. At this low pressure, a small portion of the refrigerant boils (or flashes), cooling the remaining liquid refrigerant to the desired evaporator temperature. The cool mixture of liquid and vapor refrigerant (A) travels to the evaporator to repeat the cycle.
The vapor-compression refrigeration cycle is reviewed in detail in the
Refrigeration Cycle Air Conditioning Clinic.
