Performance evaluation of a desiccant coated heat exchanger with two different desiccant materials

Abstract

In desiccant cooling systems, the desiccant material reduces the humidity in the process air by removing its moisture. The reduction of the temperature is achieved by heat exchangers, evaporative coolers or conventional cooling coils. These systems draw interest because they allow the use of low quality energy which can support sustainability through energy efficiency.The desiccant coated heat exchanger is a structure that allows the simultaneous removal of adsorption heat and dehumidification in a single element. This structure is a system element that can contribute extensively to the indoor air humidity control for new generation dehumidification in air conditioning systems. Besides, the dehumidification efficiency of this system has been found to be better than the conventional desiccant wheel. In this study, a desiccant coated small-scale heat exchanger is evaluated by simulation. Silica gel and aluminium fumarate are analysed as desiccant material coatings in this work. Simulations are performed according to two model configurations which are adiabatic and water-cooled cases respectively. Heat and mass transfer characteristics are determined for the two cases as well as the dehumidification and regeneration capacities. The performances of the two materials are compared based on the results of the simulations. Results of the study show the advantages of the water-cooled dehumidification over the adiabatic dehumidification and silica gel composite coating over aluminium fumarate coating.