Experience with refrigerant mixtures

This paper summarizes experience gained with refrigerant mixtures in laboratory heat pump tests. A test facility was designed and built to measure the steady-state and cyclic performance of two air-to-air heat pumps. Hardware modifications to utilize the temperature glide of zeotropic refrigerant mixtures were investigated. The time-dependent operating concentrations of mixtures were measured. A large temperature glide mixture was used to examine the change in performance. A simulation program for an entire heat pump system was developed. This program was verified with experimental data and also was utilized to estimate the behavior of mixtures in different types of heat exchangers.