Performance and Simulation of Once-Through and Separating Cycles Using Nonazeotropic Refrigerant Mixtures

摘要

A simulation program developed at the University of Illinois at Urbana-Champaign was refined to match the performance of an experimental refrigeration facility located in the laboratory of the Department of Mechanical and Industrial Engineering in which the working fluid was a nonazeotropic mixture of two refrigerants, R-12/R-114. When simulating this two-evaporator system the program provided insight on how to control the physical system while independently regulating the refrigerating capacity and temperature level of each evaporator. A further role of the simulation program was to identify the extent to which the reduction in heat-transfer coefficients affected the cycle efficiency. The reduction in compressor power for given refrigeration loads and temperatures when using R-12/R-114 mixtures was of the order of 2% in comparison to using R-12 alone. Were it possible to maintain the same heat-transfer coefficients as with R-12 alone, the simulation program predicted an energy saving of 3.5%. (ERA citation 12:000673)