Research on the thermodynamic properties of binary mixtures containing R1234ze(E) based on Helmholtz model

Abstract

R1234ze(E) has excellent environmental protection properties, but the unsatisfactory latent heat of vaporization and volumetric cooling capacity impede its application. A mixture with excellent thermophysical properties and environmental performance can be obtained through blending R1234ze(E) with other working fluids. In this paper, the vapor-liquid equilibrium data of R1234ze(E)/R32, R1234ze(E)/R152a, R1234ze(E)/R290, and R1234ze(E)/R161 were correlated by Helmholtz equation of state combined with the mixing rule, and the calculation model of thermodynamic properties was established. On this basis, temperature glides, latent heats of vaporization, saturated vapor pressures, and other thermodynamic properties of binary mixtures containing R1234ze(E) were calculated and compared. The results indicate that the standard boiling points and critical temperatures of the four binary mixtures containing R1234ze(E) were similar to those of R22 in most mass concentration ranges. And their saturated vapor pressures at 298.15 K were all lower than that of R22 except for R1234ze(E)/R32 mixed in a few proportions. The latent heat of vaporization and specific heat capacity at a constant pressure of the four mixtures were larger than those of R1234ze(E) and adding the four pure refrigerants with excellent thermodynamic properties into R1234ze(E) helps to improve the latent heat of vaporization and specific heat capacity of the binary mixtures. Among the four mixtures, R1234ze(E)/R290 is an azeotropic mixture and R1234ze(E)/R152a is a non-azeotropic mixture. Finally, the recommended mixing ratios of R1234ze(E)/R32, R1234ze(E)/R152a, R1234ze(E)/R290, and R1234ze(E)/R161 to replace R22 were in the range of 0.56/0.44∼0.76/0.24, 0.58/0.42∼0.71/0.29, 0.27/0.73∼0.85/0.15, and 0.58/0.42∼0.84/0.16.