Experimental study of the heat transfer coefficient during condensation of refrigerant R1234yf in a 4.8-mm internal diameter smooth horizontal tube

This study presents an experimental investigation into the condensation heat transfer of R1234yf in a 4.8-mm horizontal tube at various mass flux rates of 150 kg/(m2 s), 200 kg/(m2 s), 250 kg/(m2 s), and 300 kg/(m2 s) and saturation temperatures of 30 °C and 35 °C, covering a vapor quality range of 10–90%. In addition to analyzing the experimental results, comparisons were made with other correlations in the literature. The results showed that the heat transfer coefficient increases with vapor quality, and for the tested temperatures, the average heat transfer coefficient of R1234yf was found to be lower than that of R134a by 28% and 9% for average mass fluxes of 175 kg/(m2 s) and 275 kg/(m2 s), respectively. The study also investigated the influence of mass flux on the heat transfer coefficient. The heat transfer coefficient decreased with an increase in the condensation temperature, being 7% lower for 35 °C than for 30 °C. Additionally, the experimental values of the condensation heat transfer coefficient were compared to those predicted by ten correlations in the literature and a neural network model. The Haraguchi (Trans Jpn Soc Mech Eng 60:2117e2124, 1994b) correlation was found to be the most appropriate for estimating the heat transfer coefficient, despite having lower precision than the neural network model, which provides all necessary details for implementation by potential users.