An evaporative cooler, swamp cooler, desert cooler, and a wet air cooler cools air through the simple process of the evaporation of water. Evaporative cooling works by utilizing water vaporization. The temperature of dry air drops significantly through the transition of liquid water to water vapor and water vapor is essentially evaporation. This process can cool air with much less energy than with refrigeration. In extremely dry climates such as the Southwest portion of the United States, evaporative cooling has an added benefit of also moisturizing the air which prevents things from becoming to dry. Evaporative cooling always requires a water source and must constantly have water to operate and cool the air.
An evaporative cooler is really just a large fan that blows air through water soaked pads producing a cooling affect. The fan pulls hot outside air through the pads and into the cooler and blows the cooled air out.
The Evaporative Coolers pads are most commonly made of wood shavings.
A small recirculating water pump located inside the cooler pumps water through supply lines that distribute water to the top of the cooling pads.
When water reaches the top of the pads the water saturates the pads by dripping through them constantly. The water goes through the pads and collects in the bottom of the cooler. The small recirculating water pump sends the collected water back to the top of the pads and this is a continuous operation.
The fan has 2 functions, it pulls in hot air and pushes out cooled air. The coolers fan pulls the warm outside air in and through the pads.