الفهرس Only 14 pages are availabe for public view
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Abstract
The thermal performance of a direct evaporative air cooler DEAC is analyzed numerically and experimentally. The effect of a wide variety of parameters, such as air velocity, water velocity, the inlet and outlet relative humidity on the thermal performance of the DEAC are investigated. A simple mathematical model for countercurrent evaporative cooler is presented. The model consists of ordinary differential equations, which describes the mass and heat exchange processes, in addition to the mass energy and momentum conservation laws. The model includes the necessary equations, which present the problem initial and boundary conditions. The model inputs include the inlet temperature and the mass flow rates of both air and water, and the relative humidity of air at its inlet. The effectivenss increases with increasing relative humidity at inlet, while it decreases with increasing air dry bulb and water temperatures at inlet as well as the water mass flow rate to the air mass flow rate ratio. Nusselt number and Sherwood number increase with increasing relative humidity at inlet, while they increase with decreasing air dry bulb and water temperatures at inlet as well as the water mass flow rate to air mass flow rate ratio. The predicted values for air and water exit properties, for given input conditions, agree well with experimental data obtained for direct evaporative cooler.