The paper studies the cycle performance of the mixture alternatives of R22. The theoretical study indicates that R143a/R227ea and R125/R227ea improve the volumetric refrigeration capacity comparing to R143a/R227ea, R125/R227ea and R22/R142b. Because of these excellent fractional distillation, R143a/R227ea and R125/R227ea can be used in change concentration volume regulation system. Experimental data are compared to theoretical results. Good agreement is found for the cases studied.