Material compatibility of HVAC&R system materials with low global warming potential refrigerants

Abstract

This article summarizes material compatibility evaluations of unsaturated hydrofluorocarbon (known as hydrofluoroolefin) refrigerants, and hydrofluoroolefin refrigerants blended with R-32, that were performed to characterize equipment reliability risks associated with the use of next-generation low global warming potential fluorinated refrigerant candidates. Material compatibility exposures were conducted with R-1234yf, R-1234ze(E), and a three-refrigerant composite blend of R-1234yf, R-1234ze(E), and R-32, with nine different elastomers, three gaskets, five polymers, and ten motor materials. Exposures were carried out in 100% refrigerant, 50% refrigerant:50% lubricant, and 100% lubricant to encompass the range of refrigerant and lubricant compositions that materials may encounter in different areas of operating systems. Two different lubricants, a polyol ester and a polyvinyl ether, were evaluated in this study, resulting in a total of 12 different exposure conditions for each of the 27 materials. A summary of material physical property changes and observations is provided, and potential system reliability implications of these findings are reviewed.