HFC & HFO Blend, low GWP, refrigeration lubricant
Although HFO refrigerants are considered the low GWP solutions to the global warming problem, some properties of HFO refrigerants prohibited the direct drop in replacement application in the refrigeration system. As a result, to replace the high GWP HFC refrigerants, HFC & HFO refrigerants are blended to combine their properties to become a workable solution. Both HFC and HFO refrigerants have similar basic properties; however, one of the HFO refrigerants properties is good miscibility to incumbent refrigeration lubricants, especially HFO-1234ze. Generally speaking, refrigerant-oil mixture with highly miscible property in low temperature evaporator will lead to more soluble phenomenon in high temperature compressor. Therefore, when refrigerant is well miscible with refrigeration oil, the dissolved refrigerant will reduce working viscosity of refrigerant-oil mixture in compressor, which could results in lower lubricity, increase wear of sliding parts, and shorter compressor durability. In our studies, we discuss the influence of lubricant in HFC & HFO blend refrigeration system, such as R513A or R450A. Compared to the lubricant performance in HFO refrigerants, the same lubricant in the HFC & HFO blend refrigerants do not lead to severe refrigerants dilution of lubricant viscosity, which causes poor lubricity due to high solubility. According to our previous study, we know the better miscibility brings the better solubility in R1234ze system. We also developed lubricants with different miscibility properties in HFC & HFO blend refrigerants in order to investigate the miscibility, solubility and lubricity performance in the HFC & HFO refrigeration systems.