Heat Transfer and Pressure Drop of R1234ze(E) and R32 during Condensation and Evaporation in Horizontal Smooth Tube

Abstract

Experimental study on condensation and evaporation heat transfer and pressure drop of R1234ze(E), R32 and R410A has been conducted with water heated double tube heat exchanger under conditions of various mass fluxes, saturation temperatures and heat fluxes. Test sections are horizontally installed smooth tubes with inner diameter of 4.35mm. The condensation heat transfer coefficient of R1234ze(E) is higher than that of R410A. On the other hand, the evaporation heat transfer coefficient of R1234ze(E) is lower than that of R410A. The heat transfer coefficient of R32 is the highest among the tested refrigerants for both the condensation and evaporation. Pressure drop is high in the order of R1234ze(E), R32, R410A. Existing correlations predict well the experimental condensation heat transfer coefficient and pressure drop. On the other hand, the evaporation heat transfer coefficient and pressure drop could not be correlated well by existing correlations. Modified correlation gives better prediction.