An experimental investigation of nucleate boiling performance for low-GWP azeotropic refrigerant R513A on a smooth tube

In the present study, an experimental investigation is conducted to study the nucleate boiling characteristics on a smooth tube having a low-GWP azeotropic refrigerant, R513A. The heat flux ranges from 5 to 90 kW/m², and saturation temperatures are 0, 6, 10, 16, and 22 °C, respectively. The performance of R513A is compared against that of R134a. The performance is in terms of heat transfer coefficient (HTC). HTCs normally increased with the rise of heat flux and saturation temperature. However, the HTCs of R513A exceed those of R134a by approximately 20–25 %. Additionally, comparative analysis of the test data and some existing correlations are made. The compared correlations include three correlations based on reduced pressure (Cooper, Ribatski and Jabardo, and Jung), as well as two correlations based on thermophysical properties. It is found that the Jung correlation gives the best overall predictive ability against the R513A data with a deviation ranging from 5 % to 10 %.