This paper uses the concept of "equivalent temperature" and presents a new standard used to evaluate vapor compression cycle. The evaluation standard eliminates the error of superheat temperature, and builds the relation of Rankine cycle and Lorenz cycle. Based on the standard, the paper compares cycle performance of R22 and its alternatives including pure refrigerants and mixtures. Refrigerant thermodynamic properties are calculated by using the Carnahan-Starling-DeSantis equation of state. The results indicate that intracycle can improve COP of all refrigerants. Intracycle reduces the volumetric refrigeration capacity of R22, R32 and R717(NH3), but all mixture alternatives can be improved.
