An
evaporative cooler (also
swamp cooler,
desert cooler and
wet air cooler) is a device that cools air through the
evaporation of water. Evaporative cooling differs from typical
air conditioning systems which use
vapor-compression or absorption refrigeration cycles. Evaporative cooling works by employing water's large
enthalpy of vaporization. The temperature of dry air can be dropped significantly through the phase transition of liquid water to water vapor (evaporation), which can cool air using much less energy than
refrigeration. In extremely dry climates, evaporative cooling of air has the added benefit of conditioning the air with more moisture for the comfort of building occupants.