Exergy Analysis of Evaporative Cooling for Optimum Energy Consumption in Diverse Climate Conditions

Authors

1 M.Sc., School of Aerospace and Mechanical Engineering, University of Oklahoma, Norman, OK, USA

2 M. Sc., Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran

Abstract

In this paper, exergy of conditioned air, exergy efficiency, irreversibility, and entropy generation of common models of evaporative cooling have been investigated in five cities of Iran. Direct evaporative cooling (DEC), indirect evaporative cooling (IEC), and two-stage IEC/DEC as the most popular methods of cooling have been modeled. Atmospheric conditions are considered as the dead state of each city. Exergy analyses of conditioned air are based on the output results of the theoretical modeling of evaporative cooling. Moreover, exergy balances of three cooling methods are derived. Thus, exergy destruction, reversible work, and entropy generatiom are calculated according to the exergy balances. The results obtained reveal that Bam, which is a hot city with medium relative humidity (24%RH), has the best exergy efficiency of direct evaporative cooling. The highest exergy efficiency of two-stage indirect/direct evaporative cooling belongs to Kerman. Kerman with the lowest dry-bulb temperature has medium relative humidity (24%RH). In addition, total output exergy of air in Yazd is more than other cities. Yazd is a hot-dried city with rather low relative humidity (19.5%RH).

Keywords