Experimental analysis of water evaporation losses in cooling towers using filters

Abstract

Water evaporation losses in cooling towers account for considerable amount of fresh water consumption, which calls for proven and economically viable technologies to address this problem. The use of filters mounted on to top of the cooling tower as a technique to reduce the amount of water evaporation losses is one of the most promising solutions and thus has been investigated experimentally in this paper. The water evaporation losses have been quantified and analyzed using four types of filters and compared to the case without filter. The filters used are metal panel aluminum, glass fiber, pleated pre-filter, and fiber glass pocket filters. Each filter was mounted on the top of the tower and each experiment consisted of five tests with ten minutes time interval between tests. The results showed that using metal panel aluminum filter, the water evaporation losses are reduced by 17%, while using the pleated pre-filter the losses are reduced by 14.30%, using glass fiber and pocket filters saves up to 13% and 11.30%, respectively of the evaporation losses. The results are attributed to the ability of each filter type to absorb and condense water droplets and to porosity, permeability and the specific surface area of each filter. Moreover, a case study is performed to estimate the potential savings of water evaporation losses for an operational 7500 TR district cooling system. The results showed that large amount of water evaporation losses, up to 700 m3/day can be saved using metal panel aluminum filter.