Study on Miscibility of Refrigeration Oil with Refrigerant

Abstract

In the refrigeration and air-conditioning industry, various refrigerants have been proposed and studied to cope with global warming and climate change. In recent years, not only fluorine-containing refrigerants but also hydrocarbon refrigerants such as propane (R 290) have started to be adopted mainly for applications with a small amount of refrigerant charge volume in various countries. Since R 290 has a high combustibility and an excessively high solubility in conventional refrigeration oils such as mineral oil or polyol ester (POE), a refrigeration oil in which a refrigerant is hardly soluble may be adopted in order to improve safeness and performances. In general, a refrigeration oil which is hardly soluble in a refrigerant is considered to be poor in oil return to a compressor. However, in this study, the refrigerant solubility of the refrigeration oil and the influence thereof, particularly the possibility that even a refrigeration oil having low solubility has no problem in oil return, including an HFC/HFO refrigerant, are reported.