Application of indirect evaporative cooling to variable domestic cooling load

Abstract The present study has been conducted into the application of the indirect evaporative cooling in fulfillment of the variable cooling load of a typical Iraqi dwelling. A two story house located in Baghdad was the object of the study. The application was evaluated through a systematic simulation, along with a comparison between two arrangements of an indirect-direct evaporative cooling system. The simulation involved the operation of the cooling system under four operating modes for variable ambient temperature and cooling load conditions during the summer season. The concept of variable air volume (VAV) was employed as a control strategy over the day by changing the supply air flow rate through a variable speed fan according to the variation in the cooling load. Hourly computerized calculations were programmed for the variable cooling load using the transfer function method (TFM) over 24 hour daily cycles. The simulation of the system included variation in the effectiveness of the plate heat exchanger employed for the indirect evaporative cooling stage and its effect upon the variation in the air flow rate. The results showed that indirect evaporative cooling would result in a comfortable indoor condition for most periods of system operation. Also, the results have shown that the coefficient of performance tends to be very high because the system consumes only fan and water pumping power.