Evaporator Core: Description and Operation

The evaporator cools and dehumidifies the air before it enters the vehicle. High pressure liquid refrigerant flows through the expansion tube (orifice) into the low pressure area of the evaporator.

The heat in the air passing through the evaporator core is lost to the cooler surface of the core cooling the air. As the process of heat loss from the air to the evaporator core is taking place, any moisture (humidity) in the air condenses on the outside surface of the evaporator core and is drained off as water.