Single-tube performance of condensation of R-134a on horizontal enhanced tubes

Experiments were conducted to study the condensation heat transfer characteristics of a horizontal enhanced tube. In the current experiment, four different enhanced tubes, including 26- and 40-fpi low-fin tubes and two three-dimensional-fin tubes, were tested. The working fluid used in the experiment is refrigerant R-134a. Data were presented in the form of heat transfer coefficients in two condensing temperatures, namely, 40.6°C and 45°C. In addition, the Beatty and Katz (1948) gravity drainage model together with a surface drainage model proposed by Rudy and Webb (1983) were compared with the present low-fin data.