The miscibility of refrigerant and lubricating oil directly affects the service life and cycle performance of refrigeration system. To solve the problem of matching new refrigerant and lubricating oil

a refrigerant and lubricating oil compatibility test system was established. The experimental study on the miscibility of R290/R1234yf and mineral oil was carried out in the temperature range of 223.15—303.15 K. The results show when R290 mass fraction in mixed refrigerant R290/R1234yf changed from 25% to 35% and oil proportion was specified at 10%±0.5%

the critical miscibility temperature of R290/R1234yf and mineral oil decreased with increasing R290. In the test range of oil proportion

based on the common refrigeration conditions

when the mass fraction of R290 in solution changed between 20% and 30%

the critical miscibility temperature was sensitive to the change of components. When the R290 mass fraction in solution was over 30%

the refrigerant/oil solution was believed to be clear and transparent. When the R290 mass fraction in solution was below 20%

the obvious stratification or large flocs would appear. By means of the element contribution evaluation method

the theoretical critical miscibility temperature prediction equation was provided and given in the form of ternary diagram

which has practical guiding significance for the development of new environmental protection refrigerants.