Modeling of simultaneous heat and mass transfer within passive down-draft evaporative cooling (PDEC) towers with spray in FLUENT

PDEC applications have rarely been integrated in buildings despite the fact that some have achieved significant energy savings. However, efforts have not been appropriately made to find relevant solutions that overcome deficiencies of PDEC tower systems and to identify potential problems with PDEC towers. This study was thus designed to understand the fundamentals of the down-draft evaporative cooling process so that they will be considered as a viable solution for improving sustainability in buildings. Computational modeling using FLUENT has been performed to properly model the main physical phenomenon of simultaneous heat and mass transfer as well as turbulent flows. A computational model dealing with turbulence and wall-bounded flows has been developed and various case studies have been performed. As a result, the unique characteristics of air flows within PDEC towers were determined, and down-draft evaporative cooling processes in various situations were explained.

► A computational model with FLUENT including turbulence and wall-bounded flows has been developed.
► It found unique features of PDEC flows such as backflows.
► An impact of droplet sizes and air mass flow rate to the performance of a PDEC tower with spray system was investigated.
► The computational model and findings are expected to be a key solution that advances the performance.