Drip-Type Direct Evaporative Coolers

Abstract

The commonest evaporative coolers are essentially cubical metal or plastic boxes with large flat vertical air filters, called “pads,” in their walls. Consisting of very wettable porous materials, these are kept moist by water dripped continuously into their upper edges. Motorized fans within the boxes draw air in through the pads, which both cools and humidifies the air, and it discharges from the coolers as “washed air” for cooling use. Many coolers have two or three fan speeds, so users can modulate outputs as needed.