U.S. Department of Energy - Energy Efficiency and Renewable Energy
Federal Energy Management Program – Operations and Maintenance
Key Components of Chillers
There are two basic types of chillers—mechanical compression chillers and absorption chillers.
Mechanical Compression Chillers
| Component |
Description |
| Evaporator |
Component in which liquid refrigerant flows over a tube bundle and evaporates, absorbing heat from the chilled water circulating through the tube bundle. |
| Compressor |
Pumps the refrigerant vapor to the condenser by raising the refrigerant pressure (and thus, the temperature). |
| Condenser |
Component in which refrigerant condenses on a set of cooling water coils giving up its heat to the cooling water. |
| Expansion Valve |
The high-pressure liquid refrigerant coming from the condenser passes through this expansion device, reducing the refrigerant's pressure (and temperature) to that of the evaporator. |
Absorption Chiller
| Component |
Description |
| Evaporator |
Where evaporation of the liquid refrigerant takes place. |
| Absorber |
Where concentrated absorbent is sprayed through the vapor space and over condensing water coils. Since the absorbent has a strong attraction for the refrigerant, the refrigerant is absorbed with the help of the cooling water coils. |
| Generator |
Where the dilute solution flows over the generator tubes and is heated by the steam or hot water. |
| Condenser |
Where the refrigerant vapor from the generator releases its heat of vaporization to the cooling water as it condenses over the condenser water tube bundle. |
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