Experimental study on the contribution of R161 and R1234yf to the miscibility of R32 with lubricating oils

Abstract

R32 has been considered as a promising alternative refrigerant with superior energy efficiency. However, it has relatively high exhaust temperature and poor miscibility with commonly used lubricating oil. This paper mainly studied the contribution of R161 and R1234yf to the miscibility of R32 with mineral oil (MO), polyol ester (POE) and polyvinylether (PVE) oils. Firstly, the critical miscibility temperature (TCMT) of R32, R161 and R1234yf with lubricating oils was measured in the temperature range from 223.15 to 303.15 K. Continued, the influence reasons on the miscibility of refrigerants with lubricating oils were analyzed and a new miscibility evaluation parameter was proposed to predict the miscibility level. Then the TCMT of R32/R161 and R32/R1234yf with lubricating oils was measured in the oil mass fraction range from 5% to 30%. The experimental results indicated that the influences of R161 and R1234yf on the miscibility of R32 with POE and PVE oils were obvious, and the contribution of R161 was greater than that of R1234yf. Finally, the theoretical miscibility temperature was estimated by the fitted equations with acceptable accuracy and given in the form of ternary diagram.