Effect of Using Pad Manufactured from Agricultural Residues on the Performance of Evaporative Cooling System

The present study was carried out to investigate the performance criteria of rice straw (RS) and palm leaf fibers (PLF) as pad materials of a pad and fan evaporative cooling system. Pad thickness and pad face air velocity were taken into consideration. Reducing heat stress in terms of temperature reduction (T and ΔT), saturation efficiency (SE) of the pad and unit of the evaporative cooler performance (Unit ECP) were the main criteria to judge pad materials. The results revealed that: For both pad materials, the highest value of temperature reduction was achieved with 15 cm pad thickness and 0.5 m/s pad face air velocity; while the lowest value occurred with 3 cm pad thickness and 0.5 m/s pad face air velocity. The cooling effect for all rice straw treatments was higher than that for palm leaf fibers. It ranged from 5.67 °C (278.67 K) to 8.66 °C (281.66 K) for all rice straw treatments, while in palm leaf fiber treatments it ranged from 5.01(278.01 K) to 7.50 °C (280.50 K). The saturation efficiency decreased by increasing pad thickness for all pads made from palm leaf fibers. Two multiple regression equations were developed to describe the relationship between SE and pad face air velocity (V), pad thickness (d), outside air relative humidity (RHo) and outside air dry bulb-temperature. The highest and lowest mean unit evaporative coolers performance values (Unit ECP) were found for rice straw pad with 15 cm thickness, 1.05 m/s pad face air velocity and 3 cm pad thickness, 0.3 m/s pad face air velocity, respectively. Evaporative cooling pad material is a method to reduce heat stress in agricultural structures. Rice straw pad material is better than palm leaf fibers from the view point of cooling effect and saturation efficiency in most treatments