The effect of a polyol ester lubricant on equilibrium pressure, liquid density and viscosity is presented for R22, R125, and R134a at varying temperatures and concentrations. Preliminary vapour-liquid equilibrium (VLE) data and miscibility observations are also presented for an R32/R125 blend (50%/50%) with the ISO 68 polyol ester (POE). Real-gas behaviour is modelled using the vapour-phase fugacity, and vapour pressure effects on liquid fugacities are taken into account with the Poynting effect. Positive, negative, and mixed deviations from the Lewis-Randall rule are observed in the activity coefficient behaviour. Departures from ideality are related to molecular size differences, intermolecular forces in the mixture, and other factors. The data are discussed in the context of previous results for other refrigerants and thermodynamic modelling of refrigerant and oil mixtures.

KEYWORDS: year 1996, refrigerants, lubricants, R22, R134a, R125, R32, R125, mixtures, measuring, vapour pressure, viscosity, equilibrium, oil, thermodynamics, calculating, physical properties