Prediction of two-phase condensation characteristics of some alternatives to R-22 inside air/refrigerant enhanced surface tubing

Abstract

The results of an experimental study on the heat transfer characteristics of two-phase flow condensation of some azeotropic refrigerant mixtures, proposed as alternatives to R-22, on air/refrigerant horizontal enhanced surface tubing are presented. The condensation data indicated that the heat transfer coefficient of the blend R-408A has the highest heat transfer rate among the blends under investigation. The condensation data also showed that R-507 and R-404A have similar heat transfer rates to that of R-22 when plotted against the refrigerant mass flow rate. It can also be observed that, as the mass flux increases, the heat transfer coefficient increases. Correlations were proposed to predict the heat transfer characteristics such as average heat transfer coefficients as well as pressure drops of alternatives to R-22 such as R-507, R-404A, R-407C and R-408A, as well as R-410A in two-phase flow condensation inside enhanced surface tubing. In addition, proposed correlations were found to fairly predict the two-phase flow heat transfer condensation data. Copyright © 2000 John Wiley & Sons, Ltd.