Systematic Study of the Solution Properties of Low Global Warming Potential R-404A Replacement Refrigerant Blends with Various Polyol Ester Lubricants

摘要

This paper extends our previous investigations of refrigerant/lubricant property optimization to refrigerant blends; in particular, to nonflammable low global warming potential replacements for R-404A (GWP= 3952) with GWP < 1500. Solution phase behavior and solution property data are reported for R-449A/B and R-448A in combination with three POE lubricants of varied chemical structure, and corresponding varied solubility/miscibility with the refrigerant. When comparing refrigerant blends with a single lubricant, R-449A/B and R-448A gave a lower isobaric suction condition viscosity curve than R-404A; suggesting that these new refrigerant blends may give improved compressor energy efficiency at low operating temperatures. The results suggest that, although each polyol ester lubricant exhibits very different miscibility behavior in the refrigerant blends, the resulting solution viscosities at normal operating conditions is nearly identical for the isobaric suction curves. However, there were differences observed in the solution viscosities in the isobaric discharge condition curves. The overall conclusion is that there may be opportunities to improve frictional and wear performance through optimization of lubricant properties depending on compressor design and operating conditions. All three refrigerant blends can use the ISO 32 POE lubricants currently in use with R-404A without any detriment to performance or reliability.