All the parts of a swamp cooler are contained in a metal casing or a frame. The frame usually has a box-like shape and contains all the necessary equipments required to blow wet air into the room. The sides and the back panel of the frame are filled with pads made of cellulose, which really help in maintaining the temperature of the water present in the cooler. The pads are replaced every season, as they start breaking after a certain period of time.
The bottom of the cooler is like a big square bowl, especially designed to contain some water in it. The water pump is also installed at the bottom of the cooler, which sprays water on the cellulose pads.
An electric motor with pulleys is also a main part of the cooler, which runs the fan installed in the front panel of the cooler. When you turn on the cooler, the fan at the front panel pulls warm outside air through the cellulose pads and blows it into the room. The air that passes through the pads becomes cooler due to evaporation and the occupants of the room get cool air blown by the fan in the cooler.
Usually, the evaporation process cools the outside air by around 20 to 30 degrees Fahrenheit before the fan throws it into the room. The difference in the temperatures depends on the level of humidity present in the air outside. The lesser the humidity goes, the more effective the swamp cooler becomes. That is the reason why swamp coolers are usually used in dry climate areas.