Experimental isobaric heat capacity of liquid HFC-32+HFO-1234ze(E) mixture and extension of a predictive corresponding state equation to HFC mixtures

In this work, isobaric heat capacity of liquid refrigerants mixtures was investigated experimentally and theoretically. First of all, experimental isobaric heat capacity data of a representative HFC-32+HFO-1234ze(E) binary mixture was obtained by a modified Calvet calorimeter at different temperatures and concentrations. After that, a previously proposed corresponding state equation, which was used for estimation of isobaric heat capacity of pure liquid HFCs and HFOs refrigerants, was extended to mixtures. Different mixing rules for pseudo-critical parameters were tested and a comparison between predicted values and experimental data was carried out in search of a best mixing rule. In the end, the corresponding state equation coupled with the selected mixing rule was applied to other binary mixtures R-410A, R-507A and ternary mixtures R-404A, R-407C. It was found that the calculated results agreed well with their fundamental Helmholtz equations of state. The average absolute deviation was 0.88% and maximum absolute deviations were no more than 1.90%.