Experimental Research on the Dissolution Characteristics of R474A and R479A in Lubrication Oils

The novel refrigerants R474A and R479A have demonstrated superior performance in terms of environmental friendliness, safety, and thermodynamic properties. However, their solubility in refrigeration oils remains unknown. This study investigates the miscibility and solubility of R474A and R479A in the lubrication oils RB68 and RB100EV. The critical miscibility temperatures of R474A and R479A in RB68 and RB100EV were tested within a temperature range of -20 ℃ to 20 ℃. The findings reveal that within the experimental temperature range, R474A is miscible in RB68 and RB100EV solutions at different oil contents, and the critical miscibility temperature is lower than -20 ℃. R479A maintains a homogeneous transparent state in both refrigeration oils, with critical miscibility temperatures below -20 ℃. Based on the isochoric saturation method, the solubility of R474A and R479A in RB68 and RB100EV was tested within a temperature range of -20 ℃ to 60 ℃. The solubility of both novel refrigerants in RB68 and RB100EV increased with pressure and decreased with temperature. Based on these findings, for a given temperature range, the enhancing effect of pressure on solubility increases significantly as the pressure increases.