An experimental investigation was conducted to determine the effect of row spacing between horizontal enhanced tubes on average condensation heat transfer coefficients. A test chamber was constructed to condense Refrigerant-113 on the shell side of a vertical bank of four horizontal tubes. The surface geometries included two sizes of smooth tubes and three types of enhanced tubes (GEWA-SC, GEWA-TW, and GEWA-TWX). The effects of inlet water temperature and flow rate are reported. The experimental data and observations of the condensation process showed that the condensation process showed that the condensation phenomenon is affected by the condensate-removal mechanism. The drainage mechanism is controlled by gravity and surface tension. The condensation heat transfer coefficient was very sensitive to tube spacing and water flow rate and temperature.

KEYWORDS: condensation, R113, refrigerants, experiment, tubes, horizontal, spacing, heat transfer coefficient, climate chambers, geometry, heat flow, performance, Reynolds numbers, comparing, shell and tube heat exchangers, heat exchangers.