Chillers typically cool water, which is then circulated to provide comfort cooling throughout a building or other location. Chillers can be classified by compressor type, including centrifugal and positive displacement. Chillers used to cool industrial processes are discussed under Industrial Process Refrigeration.

Categories of Equipment

Centrifugal Chillers
Centrifugal compressors, which are water-cooled, are aerodynamic or turbine type and move gas by converting kinetic energy to pressure energy. Capacities range from 200 – 21,000 kW (60 to 6,000 refrigeration tons).

Positive Displacement Chillers
Positive displacement compressors include reciprocating, screw, and scroll compressors. Reciprocating compressors can be air-cooled or water-cooled and use cylinders with pistons acting as pumps to increase refrigerant pressure. Reciprocating chillers are smaller than centrifugal chillers with a capacity range of 10 – 1,800 kW (3 – 510 refrigeration tons). In screw compressors, also known as rotary compressors, the gas is compressed by direct volume reduction between rotating screws. Screw compressors are available in several designs including single screw or twin screw. Screw chillers can be air-cooled or water-cooled and have a capacity range of 10 – 7,000 kW (3 – 2,000 refrigeration tons). Scroll compressors use a stationary scroll within a rotating scroll to compress refrigerant, and have a capacity range of 10 – 1,800 kW (3 – 510 refrigeration tons).