Performance characteristics of wet air-conditioning cooling coils with different fin patterns

Abstract

In the present study, the thermal performance and pressure drop characteristics of wet air-conditioning cooling coils are investigated under the hot arid climate of Cairo. The effect of fin patterns, fin pitch, and air velocity on the heat transfer performance of direct expansion cooling coils is presented. Five test specimens of cooling coils are tested involving flat, corrugated, and louvered fins. In addition, different fin pitches are considered for louvered-fin cooling coils. Reynolds number for the air side ranged from 65 to 1200, corresponding to face velocity of 0.43-6.65 m/s. Four methods of performance criteria are presented to interpret how different fin geometries of cooling coils could affect the overall performance of the air-conditioning unit. At a certain value of pressure drop of 50 Pa, the air heat transfer coefficient for louvered fins is higher than that of corrugated and flat fin cooling coils by 29.4% and 47%, respectively. The energy efficiency ratio for louvered fins is higher than that of corrugated and flat fin cooling coils by 9% and 17.4%. The air-conditioning system having a cooling coil with lower fin pitch and enhanced fin surfaces is more energy cost effective.