Chiller is derived from the Latin word Chill, meaning to cool. Various cycles are used to create refrigeration, the most important of which are the compression refrigeration cycle, the absorption refrigeration cycle, and the thermoelectric refrigeration cycle.

Refrigeration is the process of absorbing heat from one fluid and releasing it to another. The fluid can be air, water, or any other gas or liquid. In all refrigeration systems, keeping cool involves absorbing heat from a lower-temperature material and releasing it to a higher-temperature environment.