Using Liquid-Vapour Heat Exchanger:

While the vapour leaving the evaporator is heated through the condensate, the temperature of condensate reduced from T₄ to T₄' .The heat exchanger is necessarily a concentric kind counter-flow heat exchanger that causes the sub cooling of the refrigerant before throttling. There is no alteration in the refrigerating effect. It is performed as the heat transfer from the outside is highly unwanted as it increases the energy input to the compressor & the vapor superheating at the discharge of the compressor.

 Superheating of Vapour in a Counter-Flow Heat Exchanger