Thermodynamic properties of 1,1,1,2-tetrafluoroethane (R-134a) + 2,3,3,3-tetrafluoropropene (R-1234yf) mixtures: Measurements of the critical parameters and a mixture model based on the multi-fluid approximation

Thermodynamic properties are discussed for 1,1,1,2-tetrafluoroethane (R-134a) + 2,3,3,3-tetrafluoropropene (R-1234yf) mixtures. The critical temperatures, densities, and pressures experimentally determined are first presented with their uncertainties. Subsequently a mixture model for calculations of thermodynamic properties is formulated using the multi-fluid approximation. Comparisons to experimental data show that the mixture model calculates the vapor-liquid equilibrium and densities of the mixtures with reasonable accuracies. The critical parameters are also well represented by the mixture model.