Abstract
An experimental study was conducted to evaluate the use of palm-based insulators for existing overhead water tanks in arid regions, where it becomes extremely hot during summer and fairly cold during winter. In summer, water temperature exceeds 40 A degrees C during daytime, whereas in winter it drops to as low as 10 A degrees C during night times and early mornings. The objectives of the study were: (1) to reduce the peak water temperatures to comfortable levels for safer domestic consumption during summer, and (2) to save excessive electric energy required to warm up the water during winter. Palm leaves and fronds were used to wrap a prototype tank; the water temperatures were measured continuously and compared to those in a reference unwrapped tank. The efficiency of the insulators was assessed based on the relative amplitude ratio of the water and ambient air temperatures, in addition to the time lag between the times of temperature extremes of air and water in the tanks. The results of the summer experiments indicate that the water temperature fluctuations in the palm-insulated tank are 75 % less than those in the reference tank. The time lag of the peak water temperatures in the palm-insulated tank was two to three times longer than that in the reference tank. Sprinkling of the palm leaves with small amounts of water resulted in reducing the peak water temperatures by 7 A degrees C compared to the reference tank. During winter, the results of the experiments indicate the estimated electric energy saved is on average 28 %.