Significance of parameters affecting the performance of a passive down-draft evaporative cooling (PDEC) tower with a spray system

PDEC towers with spray systems are known to achieve substantial energy savings. Various parameters such as the wet-bulb depression, the tower height, and the wind speed have been known to be key factors affecting the performance of the system. To date, the significance of these parameters and other important factors have not been adequately treated in the literature. There also has been a lack of models that can successfully investigate potential benefits of the system under various conditions where this particular system could be applicable. To address these critical issues, this study performed a parametric analysis by using a FLUENT model validated against experimental data. It demonstrated the significance of individual parameters including water droplet sizes. As a result, practical design guidelines for important system parameters were presented. A statistical analysis was then used to formulate analytic models that account for all of the relationships found in this study between the parameters and the supply air conditions of the system. Two regression equations were formulated for predicting supply air temperature and velocity.