Evaporator Core: Description and Operation

The aluminum evaporator core cools and dehumidifies the air before the air enters the passenger compartment. High pressure liquid flows through the expansion (orifice) tube and becomes low pressure refrigerant before entering the evaporator. As the air passes through the core, the cooler surfaces absorb the heat, cooling the air. As the air is being cooled, any humidity in the air condenses on the outside of the core. The water is then drained through an opening at the bottom of the module.