There are a variety of ways that the refrigeration cycle can be tailored to suit an application in a better way (not always necessarily resulting in a higher COP) than the simple (basic) vapor compression cycle. Addition of a single heat exchanger to the basic vapor compression cycle, exchanging heat between the fluid leaving the evaporator and the fluid leaving the condenser benefits of this cycle modification

First, since the specific enthalpy remains constant during expansion, a reduction of the specific enthalpy prior to expansion results in a reduction of specific enthalpy prior to evaporation. Therefore the unit will have more evaporative heat transfer to provide more evaporator cooling capacity. Second, the state prior to compression is further away from the saturated vapor line.

For most compressors, it is imperative that the state of the refrigerant prior to compression does not have any liquid in the form of droplets or mist, since liquid entrained in a vapor undergoing compression tends to damage the fast moving parts of a compressor, seriously degrading the performance and working life span of the compressor. For this reason, it is usually desirable for the refrigerant to enter the compressor as a superheated vapor, several degrees above the saturation temperature at the pre-compression pressure. The internal heat exchanger, by increasing the enthalpy and temperature of the pre-compression refrigerant, assists in ensuring that a superheated vapor with no liquid droplets enters the compressor. This application is for thermodynamic calculations of vapor compression refrigeration cycle with regeneration