A chiller is a machine that removes heat from a liquid coolant via a vapor-compression, adsorption refrigeration, or absorption refrigeration cycles.

Chillers transfer heat away from a space that requires climate control much like a traditional split system or package unit does, but they use water (or a water solution) to do so instead of air.

Chillers work by using a refrigeration cycle to transfer heat from the water to the ambient air or to a cooling medium, such as water.

Chiller works as follows: a pump circulates cold water or water/glycol solution from the chiller to the process. The cold fluid removes heat from the process and then heated returns to the chiller.

Chillers operate using a four-stage process: evaporation, compression, condensation and expansion.