As the liquid refrigerant evaporates it absorbs energy (heat) from the inside air, returns to the compressor, and repeats the cycle.

The primary use for CFC's is in refrigeration, both as the liquid refrigerant and as a component of the foam insulation.

Evaporation: A liquid refrigerant evaporates in a low partial pressure environment, thus extracting heat from its surroundings - the refrigerator.

It is then condensed through a heat exchanger to replenish the supply of liquid refrigerant in the evaporator.

This liquid refrigerant is pushed through an expansion valve, where pressure and temperature are reduced.

As this heat is absorbed, the liquid refrigerant evaporates into a low pressure gas.

That pressure reduction results in the adiabatic flash evaporation of a part of the liquid refrigerant.

This liquid refrigerant then provides its cooling effect at the evaporator, by absorbing external heat and turning back into a vapour.

Carrier developed "centrifugal refrigeration machines" that replaced old-fashioned rotary-driven machines and used liquid refrigerants to remove moisture from humid air.

One line is for the liquid refrigerant, the other is for gaseous refrigerant.