Evaporator Core: Description and Operation

The evaporator cools and dehumidifies air before it enters the passenger compartment. Low-pressure, low temperature liquid/vapor refrigerant enters the evaporator; flows through its tubing; evaporates; and exits the evaporator as low-pressure, low temperature, mostly vapor refrigerant. As the refrigerant evaporates, it absorbs heat from the air flowing over the evaporator. 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.