Tribology Characteristics of HFC / HFO Refrigerant Mixture with Miscible Oil

Abstract

In order to reduce the global warming potential of refrigerants used in air-conditioning systems and refrigerators, several new low GWP refrigerants in which HFO refrigerant is mixed with conventional HFC refrigerant have been proposed. Ensuring the reliability of the compressor sliding part is one of the issues in applying low GWP refrigerant to the systems. Around the sliding part there are refrigerant, refrigeration oil, and extreme pressure agent contained in the oil. By clarifying the effect of these element on the tribological characteristics, it can be reflected in the design of the sliding element. Therefore, we selected R 32, R 1234yf and several HFC / HFO mixed refrigerants, and carried out seizure resistance test in the liquid refrigerant and refrigeration oil, analysis of sliding surface reaction film, and measurement of viscosity of refrigeration oil with dissolved liquid refrigerant.