Increase of energy efficiency ratio of a direct evaporative cooler by dynamic behavior with energy and exergy analysis

Abstract

The present research is about increasing the energy efficiency ratio (EER) in current direct evaporative coolers (DEC) in Iran. Increasing the cooling load and reducing the electrical energy consumption simultaneously (increasing the energy efficiency ratio (EER)) in DEC are the main goals of manufacturers and consumers of this device. When the circulation water pump runs continuously (static state), the circulation water rate is about 1.89 to 2.90 times of the amounts recommended in the reasonable standards. In order to adjust the circulation water rate to the recommended amount by standards, the present study has utilized repetitive cyclic scheduling programs to reduce the circulation rate to the optimal amount, (by turning the circulation pump on and off by dynamic pattern operation). In other words, the circulation pump stays on only for a certain period of a working cycle, and then the pump stays off for the rest of it. The cooling load and EER were measured based on ASHRAE 133 (2015). The results indicated that the cooling load in the dynamic state increased by 5.03 and 6.18 percent compared to the static state at low and high fan speeds, respectively. Moreover, in comparison with the static state, the amount of electrical energy consumed (kW-hr) in the dynamic state decreased by 8.8 and 4.2 percent at low and high fan speeds, respectively. Finally, the coefficient of performance (COP or EER) of the DEC in the dynamic state is increased by 15.16 and 10.78 in comparison with the static state at low and high fan speeds, respectively.

Energy and exergy analysis of a downstream single-row air washer at different droplet diameters for air cooling application

“…9 Omidi et al used energy analysis and exergy analysis to improve the energy efficiency ratio of direct evaporative cooling systems. 10 Santos et al used numerical simulation to study the changes in energy and exergy during the evaporative cooling process of the air washer. They found that the inlet air's optimal temperature and humidity parameters do not match the optimal thermodynamic performance of the equipment.…”

Experimental investigation of air cooler using local palm tree waste

“…Several investigations have been carried out by different researchers to improve the performance of the EC system. The major factors that significantly affect the performance of the EC system are air flow rate, condition of ambient air like dry bulb temperature, humidity, etc., the water flow rate through the cooling pads, thickness, density, and material of cooling pads [ 8 , 9 , 10 , 11 , 12 , 13 ]. The selection of the wet media pad material depends on many factors such as safety, cost, availability, effectiveness, and application [ 14 ].…”