Abstract
The performance of one-stage direct evaporative cooler (DEC) and two-stage indirect-direct evaporative cooler (IEC-DEC) in the environment of Saudi Arabia is assessed experimentally. The wet pad used in direct evaporative coolers is one of the main parts affecting the output of an evaporative cooler. In this study, three combinations of pad materials: a combination of aspen fiber and corrugated cellulose (Case-I), corrugated cellulose (Case-II), and aspen fiber (Case-III) were focused as a wet media for water evaporation and the performance of these pad materials was analyzed in detail. The main design parameter considered is the water flow rate in the designing of both coolers. During the testing of both coolers the ambient temperature in the range from 28 degrees C to 42 degrees C and relative humidity lower than 65% were considered to cool the working air. The air temperature and relative humidity were measured and the effectiveness of the coolers was determined. The results obtained show that effectiveness of the IEC-DEC system is in range of 95-110%, while that of DEC amounts to 85-93%. As an overall the IEC-DEC system with pad material of Case-I showed a comparatively better performance.