Heat transfer and pressure drop characteristics of high temperature condensation of R245fa and R1233zd in a plate heat exchanger

The paper presents an experimental investigation regarding the heat transfer and pressure drop characteristics of R245fa and R1233zd under working conditions prevailing in the condenser of heat pumps and organic Rankine cycle systems. The heat transfer coefficient and pressure drop were measured based on two types of heat transfer processes, namely, complete and partial condensation. The working fluid at the inlet of condenser for both the two modes of condensation is slightly superheated vapor not exceeding 5 K, while the working fluid at the outlet is saturated liquid and liquid-vapor mixture in the complete and partial condensation, respectively. The working conditions covered relatively high saturation temperatures of 80 °C and 90 °C. Based on the experimental results, the thermal-hydraulic performance of R245fa and R1233zd were compared. This comparison provides a preliminary assessment of using the new-generation hydrofluoroolefin R1233zd as a replacement for R245fa due to environmental reasons. In addition, the experimental results in this study were compared with the predicted values from the correlations developed based on previous test data for lower condensation temperature. The results suggest that the average heat transfer coefficient is 44 % higher for R1233zd than that of R245fa. Using the correlations developed previously for lower condensation temperatures, 97 % of the data was predicted within a ±30 % bandwidth