Experimental Investigation of Solubility, Viscosity, and Safe Application of R-1270 in Polyol Ester and Polyvinyl Ether Lubricants

Propylene (R-1270), an environmentally friendly hydrocarbon refrigerant, holds potential for vapor compression and organic Rankine cycles. However, comprehensive data on its solubility and viscosity in synthetic lubricants, such as polyvinyl ether (PVE) and polyol ester (POE) oils, are limited. In this study, R-1270 solubility and viscosity were measured using the isochoric saturation method in PVE and POE oils at temperatures from 283.15 to 353.15 K. The data were regressed using the NTRL activity coefficient and Eyring-NRTL models. The NTRL model showed AARDs of 1.84% (POE32) and 1.02% (PVE32), with MARDs of 4.91% and 5.19%, respectively. The Eyring-NRTL model achieved AARDs of 0.31% and 0.53%, and MARDs of 5.7% and 4.67%, indicating excellent agreement with experiments. Daniel plots, incorporating temperature, pressure, viscosity, and oil content, were generated. Results show R-1270s solubility-temperature and viscosity-solubility relationships are similar in both oils: solubility decreases with rising temperature, while viscosity declines with higher solubility. Above 333.15 K, viscosity drops below 10 mPa s, potentially compromising lubrication and sealing. For safety, higher viscosity lubricants or alternatives are recommended. This study provides guidance for selecting R-1270 lubricants and highlights safety concerns.