Condensation Heat Transfer Characteristics of Hydrofluoroolefin Refrigerant R1234YF as an R134a Alternative

Abstract

This study conducts an experimental investigation to determine the condensation heat transfer characteristics of hydrofluoroolefin R1234yf and R134a on horizontal smooth and finned tubes. The experiments are conducted at a saturation temperature of 39°C with variable water cooling temperatures and velocities. Additionally, the effects of different fin geometries are investigated. The predicted condensation heat transfer coefficients on the smooth tube are lower than the experimental coefficients by 2.8−14.2% for R134a and 13.8−20.7% forR1234yf. The experimental results demonstrate that the heat flux increases with a decrease in the fin height or an increase in the fin pitch and thickness. Additionally, the heat flux increases as the water velocity increases or the water inlet temperature decreases. The results also show that the tube with the largest fin pitch, largest fin thickness, and smallest fin height provides the highest condensation heat flux. The condensation heat transfer coefficients of R1234yf are slightly higher than those of R134a for all of the experiments. Thus, this study concludes that R1234yf is a potentially environmentally-friendly alternative to R134a for condensation heat transfer applications.