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Evaporative cooler
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<p>An evaporative cooler (also known as evaporative air conditioner, swamp cooler, swamp box, desert cooler and wet air cooler) is a device that cools air through the <a href="/facts/Evaporation/tgvIlJys">evaporation</a> of water. Evaporative cooling differs from other <a href="/facts/Air_conditioning/bK2sIKQd">air conditioning</a> systems, which use <a href="/facts/Vapor-compression_refrigeration/oT3EM4nS">vapor-compression</a> or <a href="/facts/Absorption_refrigerator/m3f1UWQh">absorption</a> refrigeration cycles. Evaporative cooling exploits the fact that water will absorb a relatively large amount of heat in order to evaporate (that is, it has a large <a href="/facts/Enthalpy_of_vaporization/TbEWQDNl">enthalpy of vaporization</a>). The temperature of dry air can be dropped significantly through the <a href="/facts/Phase_transition/eLP2BY8R">phase transition</a> of liquid water to water vapor (evaporation). This 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. </p><p>The cooling potential for evaporative cooling is dependent on the wet-bulb depression, the difference between <a href="/facts/Dry-bulb_temperature/5hq9yTwl">dry-bulb temperature</a> and <a href="/facts/Wet-bulb_temperature/sBdoylUX">wet-bulb</a> temperature (see <a href="/facts/Relative_humidity/Nwb28VlT">relative humidity</a>). In <a href="/facts/Arid_climate/orfIQqrB">arid climates</a>, evaporative cooling can reduce energy consumption and total equipment for conditioning as an alternative to compressor-based cooling. In climates not considered arid, indirect evaporative cooling can still take advantage of the evaporative cooling process without increasing humidity. Passive evaporative cooling strategies can offer the same benefits as mechanical evaporative cooling systems without the complexity of equipment and ductwork. </p>