Pre-cooling with Munters media to improve the performance of Natural Draft Dry Cooling Towers

This paper presents a simulation study on pre-cooling of inlet air using Munters media to enhance the performance of a Natural Draft Dry Cooling Tower (NDDCT) on hot and dry days. The ambient humidity was kept constant at 30% while the ambient temperature ranged from 10 degrees to 50 degrees C during simulation. Three Munters media (CELdek7060, CELdek7090 and CELdek5090), each with three thicknesses, were employed to pre-cool the tower inlet air. Results show that NDDCT can benefit from pre-cooling with wetted media when the ambient air is hot and dry. The trade-off between the air pressure drop across the media and the benefit of evaporative pre-cooling of the inlet air was also examined. It was found that there is a critical ambient temperature below which pre-cooling application does not benefit NDDCT performance. The value of this critical temperature is a function of the tower design and the selection of wetted media. Amongst the studied media, only the pre-cooling with 0.10 m and 0.15 m CELdek7060 is to be useful in the studied case. The dependence of heat rejection improvement of the proposed tower on medium thickness is weak. Besides, thicker medium does not necessarily bring more benefit. (C) 2013 Elsevier Ltd. All rights reserved.