Evaporator Core: Description and Operation

- The evaporator consists of a refrigerant coil mounted in a series of thin fins to provide a maximum amount of heat transfer in a minimum amount of space. It is mounted in a housing where warm air from the vehicle interior is blown across the coils and fins.

- The evaporator receives refrigerant from the expansion valve as a low pressure, cold, atomized liquid. As this cold liquid refigerant passes through the evaporator coils, heat will follow its natural tendency and move from the warm air into the cooler refrigerant.

- When the liquid refrigerant reaches a temperature and pressure that will induce a change of state, a large quantity of heat will move from the air into the refrigerant and the refrigerant will change from a low pressure, cold, atomized liquid, to a low pressure, cold, vapor.