Development of indirect evaporative cooler based on a finned heat pipe with a natural-fiber cooling pad

Evaporative cooler is one of the methods that have been used to keep buildings at a comfortable temperature since ancient times. This type of cooler is particularly suitable for hot and arid areas. This research examines the design and testing of an indirect evaporative cooler system utilizing heat pipes as heat exchangers and natural fibers as cooling pads. An experiment was performed on a laboratory scale with three different types of natural fiber cooling pad materials: pineapple leaf, ramie, and luffa fibers. The air temperatures to be conditioned was 40 °C, with three variations of the intake airflow velocities of 0.4, 1.1, and 1.8 m/s. According to the results of this experiment, an indirect evaporative cooler system utilizing pineapple leaf fiber as a cooling pad performs better than those employing luffa and ramie fibers as cooling pads. The maximum wet bulb effectiveness of the system using pineapple fiber was 85%, maximum dew point effectiveness was 65%, and maximum energy efficiency ratio was 52.5 Btu/W.As a passive heat exchanger, the performance of finned heat pipes is also investigated, with a maximum heat absorption of 527.6 W and a temperature reduction of 9.9 °C.