What Is a Water Chiller A/C?

A water chiller air-conditioning system utilizes cold water, which flows through a coil filled with refrigerant, to cool the ambient air of the building in which the unit is located. Water used in this manner reduces the work of the air-conditioning compressor.

Heat Energy

Water chiller systems reduce the workload of air-conditioning compressors.

Water chiller systems transport heat energy between the airside, or the ambient air inside a building, chillers and outside via the cooling coils, which cool and dehumidify the air stream. Main components are a compressor, condenser, expansion valve and an evaporator. This system works via vapor compression, meaning the chiller evaporator absorbs heat from the water that the chiller is cooling.

Refrigeration Cycle

A cool mixture of liquid and refrigerant enter the evaporator where it absorbs heat, which in turn boils the refrigerant. This, in turn, allows the refrigerant to be pulled into the chiller's compressor where it is compressed to a high temperature and pressure. The refrigerant quickly loses heat and turns into a cooled liquid before leaving the chiller condenser.


Water-cooled systems have minimal drops in efficiency when compared with their air cooled counterparts at temperatures over 100 degrees Fahrenheit and are optimally efficient in dry climates. Refrigerant is also contained, minimizing handling and the potential for leaks.

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