Effect of Heat Exchanger as a Pre Cooler on an Evaporative Cooling System

Abstract

This experiment was carried out to study the effect of a heat exchanger on the dry blub temperature drop and efficiency of the evaporative cooling systems. The experiment has been applied at ALkomor village out skirts of Wad Madni – Sudan in late January 2014 . The heat exchanger was made of copper tubes, arranged in arrays. The length, the height and the diameter of the tube are 55cm, 60cm, and 1 cm respectively. The distance between tubes is 4 cm, the number of the tubes is 15 and attached to the evaporative cooling system. The Distance between evaporative cooling system and heat exchanger is 20cm. Two evaporative cooling systems direct and combined have been used in this experiment. Dry blub temperature of both direct and combined evaporative cooling system were measured and tabulated. Efficiency and change in dry blub temperature in both devices were calculated. High drop in dry blub temperature was obtained in the combined evaporative cooling system as an effect of the heat exchanger and high efficiency compared to the direct evaporative cooling system. The efficiency of the combined evaporative cooling system was greater than that of the direct evaporative cooling system which were 69% and 40% respectively . The significant difference in the efficiencies between the combined and direct evaporative cooling system as a result of this study, the combined system is recommended for the arid and semi-arid regions .