Experimental analysis of hydrofluoroolefin zeotropic mixture R1234ze(E)/R1233zd(E) condensation in a plate heat exchanger

Hydrofluoroolefins are environment-friendly working fluid and used as replacements for hydrofluorocarbons. A plate heat exchanger with a zeotropic mixture as working fluid has been widely used as a condenser in various thermodynamic systems. However, only very few studies investigated the zeotropic mixture condensation in the plate heat exchanger, and none of these studies addressed mixtures based on hydrofluoroolefins. In this paper, the hydrofluoroolefin mixture condensation in a plate heat exchanger were experimentally tested, and the characteristics of heat transfer and pressure drop were analyzed. We tested the condensation of R1234ze(E)/ R1233zd(E) with four different mass fractions at wide ranges of temperatures and flow rates. The test results suggest the R1234ze(E)/R1233zd(E) mixture with the 0.352/0.648 mass fraction presents a 54% maximum degradation in heat transfer coefficient, compared with results obtained using the ideal mixing rule of pure fluids. A modified Silver-Bell-Ghaly model and a pure-fluid correlation can predict the heat transfer and pressure drop data with a mean absolute percentage deviation of 4.1% and 16.1%, respectively. In addition, for the same temperature glide, the heat transfer coefficient and frictional pressure drop of the R1234ze(E)/R1233zd(E) are up to 13.5% and 5.4% higher than those of the R134a/R245fa, respectively.

Automated summary

This study experimentally tested the condensation characteristics of hydrofluoroolefin mixtures in a plate heat exchanger and analyzed the heat transfer and pressure drop. The results showed a decrease in heat transfer coefficient when using hydrofluoroolefin mixtures, and the predicted models can accurately predict the heat transfer and pressure drop data. Additionally, the hydrofluoroolefin mixtures exhibited higher heat transfer coefficient and frictional pressure drop compared to other mixtures with the same temperature glide.