Experimental investigation of thermophysical properties of low-global warming potential refrigerant lubricant mixtures across extreme temperature ranges.

Growing climate awareness has driven legislation to phase-out hydrofluorocarbons (HFC), accelerating the search for sustainable refrigerants. Low Global Warming Potential (GWP) mixtures of hydrofluoroolefins (HFO), hydrocarbons, and Carbon Dioxide (CO₂) are promising alternatives, yet lubricant interactions with certain refrigerant mixtures, and the resulting transport and thermo-physical properties, remain only somewhat understood. Accurate data are essential for component and system performance, especially at extreme temperatures below 233 K and above 393 K. This study presents an experimental setup to measure pressure, temperature, density, and viscosity of A1–A3 refrigerant mixtures with and without lubricants from 203 K to 463 K at up to 100 bar. As a baseline, pure R410A properties are assessed and compared with NIST REFPROP, R134a with PAG is assessed to validate the refrigerant lubricant interaction and high-temperature behaviour of R1336mzz(Z) with POE380 lubricant is also studied up to 413 K for high temperature heat pump applications.