Ordinary dryers suck in cool, dry air from the room, heat it, blow it through the clothes, and then discharge the damp, hot air outside through a vent. This dryer, on the other hand, runs the exhaust through a heat-exchange system to cool it. Cold water flows through the heat exchanger, absorbing heat from the air. As the air cools, the moisture in it condenses and runs down the drain (along with the used cooling water); the dry air is then heated again, sent back through the clothes, and the cycle continues.