Thermodynamic Property Model for the Mixtures of Difluoromethane (HFC-32) + Isobutane and Difluoromethane + Trans-1,3,3,3-Tetrafluoropropene (HFO-1234ze(E))

The vapor-liquid equilibrium (VLE) have been successfully modeled for the binary mixtures of difluoromethane (HFC-32) + isobutane and difluoromethane + trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) according to the multi-fluid approach. The mixtures studied in this work are considered as possible replacements for existing hydrofluorocarbon (HFC) refrigerants having far from negligible global warming potential (GWP). The independent variables of the model are the temperature, density, and composition. Reliable published pure-fluid equations of state are incorporated for pure HFC-32, isobutane and HFO-1234ze(E). Although the model is optimized only using experimental VLE data, it can be used to calculate other thermodynamic properties such as density and heat capacities. Therefore, the model is helpful for design and simulation of refrigeration systems using the mixtures as working fluid.