Exergy analysis of indirect direct Evaporative cooling system

Abstract

The present research work is focused on the energy and exergy analysis of an newlineindirect-direct evaporative cooling system. To achieve the goal an experimental newlinesetup is designed, fabricated and tested. An analytical model of the evaporative newlinecooling system is used to systematically verify the literature and experimental newlinedata. Energy analysis of the system is conducted on the basis of the heat and newlinemass transfer. In the direct stage of the system, wetted media pads of different newlinethickness are tested at a range of face velocities under changing atmospheric newlineconditions. Variations of important variables like wet-bulb saturation newlineeffectiveness, the number of transfer units, Nusselts number, heat transfer newlinecoefficient, cooling capacity, the coefficient of performance and water newlineconsumption in all stages of the system are analyzed. Furthermore, exergy newlineanalysis of the system is conducted for the different stages of an evaporative newlinecooling system to investigate the variations in thermal exergy, chemical exergy, newlinetotal inlet exergy, total outlet exergy and exergy efficiency, irreversibility, newlineentropy generation and sustainability index. newlineEnergy analysis of two-stage indirect-direct evaporative cooling system reveals newlinethat the wet-bulb saturation effectiveness of the system increases with the newlineincrease in thickness of cooling pads of the direct stage and decreasing the newlinechannel width of the indirect stage. Higher temperature drop is observed at high newlinewet-bulb depression, in the direct as well as indirect stages of the system. newlinev newlineConsumption of water by the IDEC increases with the increase of primary air newlinevelocity and thickness of pads. newlineExergy analysis reveals that the selection of dead-state for the calculation of the newlineexergy of moist air is very important. With the change in dead-state analysis of newlineevaporative cooling system drastically changes. Exergy efficiency of the newlineindirect-direct evaporative cooling system depends on the total output exergy of newlineair, exergy transfer associated with heat transfer in the indirect stage, and newlineincrease in humid