Foaming characteristics of refrigeration oil mixed with R454B, R32, and R1234yf refrigerants by stirring action.

Refrigerant compressors contain refrigeration oil, providing lubrication, sealing, and cooling. The oil and refrigerant generally have good solubility to prevent lubrication failure. However, the refrigerant dissolving too much into the oil may cause the foaming of the mixture. This foaming phenomenon causes the oil to discharge into the refrigeration system, resulting in insufficient oil in the compressor. In this research, the foaming characteristics of the mixture were experimentally investigated by the stirring action of blade rotation in a hermetic chamber. Polyol ester (POE) oil was used as the refrigeration oil, and the refrigerants were R454B, R32, and R1234yf. The results showed that the mixture’s foaming height increased as the blade rotation speed increased. The violent range of the foaming depended on the refrigerant concentration and type. Compared to R32 and R1234yf, which are components of R454B, the violent foaming in R454B was detected in a wider concentration range.