A PERFORMANCE STUDY OF DEHUMIDIFICATION IN AN EVAPORATIVE COOLING SYSTEM USING THERMOSYPHON HEAT PIPES

Abstract

This study investigates the performance enhancement of an evaporative cooling system by integrating thermosyphon heat pipes to improve dehumidification efficiency in hot and humid climates. The experimental setup comprised a thermally insulated cubic test chamber (100 × 100 × 100 cm³) fitted with a cellulose-based cooling pad, axial flow fans, and five copper heat pipes (9.5 mm in diameter and 40 cm in length) charged with R-134a refrigerant. The heat pipes were positioned upstream of the cooling pad to passively extract latent heat and reduce moisture content in the incoming air prior to evaporative cooling. Experiments were conducted under two levels of natural solar radiation, averaging approximately 600 W/m² and 750 W/m², respectively, recorded using a pyranometer at 30-minute intervals. Measured parameters included dry-bulb temperature and relative humidity, collected using calibrated K-type thermocouples and digital hygrometers. The results indicate that the heat pipe system effectively reduced the relative humidity of supply air by approximately 6% to 10%, with maximum reductions reaching 12.5% under high solar intensity. This pre-conditioning process not only lowered the latent cooling load but also enhanced overall cooling performance. While the dry-bulb temperature increased slightly, thermal comfort improved significantly. The findings highlight the potential of this passive hybrid approach to enhance indoor environmental quality and energy efficiency in tropical buildings. Future work should focus on airflow optimization and the use of alternative refrigerants to refine system applicability in real-world scenarios.