chiller

A chiller is a heat removal device that uses a refrigeration cycle to cool a circulating liquid, typically water. The chilled fluid is used to absorb heat from building spaces or industrial processes and is circulated back to the chiller for re-cooling.

In vapor-compression chillers, a refrigerant undergoes compression, condensation, expansion, and evaporation. They are available as air-cooled or water-cooled units and come in various mechanical configurations, including centrifugal, screw, and reciprocating compressors.

Absorption chillers use heat input to drive a refrigeration cycle with a refrigerant-absorbent pair (for example water and lithium bromide). They are often used where waste heat or cheap heat is available, though their cooling capacity per unit volume is typically lower and electrical energy use can be higher.

Applications include large commercial buildings, hospitals, data centers, and industrial processes. Output is commonly rated in tons of refrigeration (1 ton equals 12,000 BTU per hour). Efficiency is described by COP or EER. Selection factors include capacity, efficiency, space, water availability for water-cooled systems, and refrigerant type.

Environmental and safety considerations: refrigerants have ozone depletion and global warming potential concerns; newer systems use lower-GWP substances and leak prevention; regular maintenance is essential.