PAST, PRESENT AND FUTURE WORKING FLUIDS FOR REFRIGERATION AND HEAT PUMPING CYCLES

摘要

In any thermal energy conversion systems such as heat pumping system, it is needless to emphasize a vital importance of selecting the optimum working fluids so as to achieve the designed performance of the system. In the present paper, the author attempts to summarize an overview on the development of working fluids for heat pump, or refrigerants in general for air-conditioning and refrigeration system, over the last several decades in the light of various obstacles recognized in the past. It is no doubt, however, that the global environmental issues such as stratospheric ozone depletion and global warming have impacted the air-conditioning and refrigeration industry worldwide like no other event in history. The discussion also covers the current state of the arts to select the optimum refrigerants among proposed candidates including hydrofluorocarbon refrigerant mixtures and natural working fluids. For the future perspectives, some of the existing novel challenges in progress will also be presented.