Chilled water air conditioning systems are commonly used in buildings such as shopping centres, airports and office blocks or industrial situations that need large scale cooling capacity.

In chilled water plants, water is chilled to around 7°C by the refrigeration plant. This chilled water is pumped to various air handling units (comprising cooling coil, blower and ducts) throughout the building. The water then picks up the heat generated from this process and returns to the chiller at around 13°C when the process is repeated.

Water Chiller types include reciprocating, screw, centrifugal and absorption chillers. Reciprocating water chillers use piston-type, positive displacement compressors which are found in small and medium capacity systems. Screw Centrifugal chillers are most commonly used in commercial water chillers and found in medium and large capacity systems. Absorption chillers are found in large capacity systems, they use water as a refrigerant and steam to cause water and lithium bromide solution to separate.