1.Hot air enters the cooler -Hot outside air enters the cooler via the inlet.

2.Hot air passes through the core -the core is a heat exchanger consisting of alternating dry and wet channels. -All of the air passes along the dry channels and gains no additional moisture.

3.Warm, moist air exhausted outside -As the air exits the dry channels ,a portion of the conditioned air is returned through the wet channels. Through evaporation and conduction, it gains both moisture and heat. The moist, warm air is then exhausted outside of the building. -No moisture is transferred across the membranes between the dry and wet channels; only temperature (heat) is transferred. -The heat passes out of the air in the dry channels through the membrane and into the air passing through the wet channels.-In this way, the air in the dry channels becomes progressively colder but gains no moistures.

4.Fresh, cool outside air passes into the building -The air passing along the dry channels in the core is cooled, with no moisture added. -This fresh, cool air passes into the building.