/ ˈer kənˈdɪʃn̩ɪŋ /
1. Process by which air is cooled for climate control.
2. An air-conditioner.
System that controls the state of the air inside a building or vehicle. A complete air-conditioning unit controls the temperature and humidity of the air, removes dust and odors from it, and circulates it by means of a fan. US inventor W H Carrier developed the first effective air-conditioning unit 1902 for a New York printing plant.
The air in an air conditioner is cooled by a type of refrigeration unit comprising a compressor and a condenser. The air is cleaned by means of filters and activated charcoal. Moisture is extracted by condensation on cool metal plates. The air can also be heated by electrical wires or, in large systems, pipes carrying hot water or steam; and cool, dry air may be humidified by circulating it over pans of water or through a water spray.
A specialized air-conditioning system is installed in spacecraft as part of the life-support system. This includes the provision of oxygen to breathe and the removal of exhaled carbon dioxide.