Waterless Air Coolers

air coolers
(Air cooler) An air cooler is any device for cooling the air inside a building, room, or vehicle. . Air coolers are used in thermally insulated casings to form refrigerators and are also used in buildings to cool rooms.
(Air Cooler) Another term for an evaporative or swamp cooler.  This type of device uses simple evaporation of water to cool the air.

waterless
As a general term, a substance is said to be anhydrous if it contains no water. The way of achieving the anhydrous form differs from one substance to another.
arid: lacking sufficient water or rainfall; "an arid climate"; "a waterless well"; "miles of waterless country to cross"
(waterlessness) dryness: the condition of not containing or being covered by a liquid (especially water)