Humidification and filtration performance study using Luffa packing in a dual stage system

Abstract Cooling and humidification are commonly used in air conditioning systems, particularly for cooling applications. Evaporative cooling utilizes packing materials that retain water particles on their surface, increasing interaction with the incoming fluid stream. At the same time, filtration efficiently removes impurities from the water. This paper focuses on a novel approach where a grey water is used for humidification process with filtration using a naturally avaliable packing. It involves in designing a combined humidification and filtration unit, where grey water is filtered through a multi-stage filter to improve water quality. The water is then uniformly distributed over packing, while air moves in a counterflow arrangement to produce cold, humidified air. Luffa packing is used in this study, and its performance is compared to standard Celdek 7090 packing. Experiments were conducted at varying Reynolds numbers with a fixed water flow rate. Results showed that Celdek packing exhibited slightly higher humidification performance than Luffa packing, with a deviation of less than 20%. The dual-stage unit achieved an efficiency of 71.11%, a Coefficient of Performance (COP) of 1.16, rate of evaporation of 0.39 g/s, & pressure drop of 63.33 Pa. And the water flow rate of 2 LPM yielded optimum humidification values. Grey water filtration was performed both with and without activated charcoal, demonstrating the unit's efficient filtration capabilities.