A review on desiccant coated heat exchangers

Abstract

Fixed bed and rotatory desiccant systems have been widely studied and used for dehumidification; they suffer from decreasing sorption capacity as the desiccant's temperature increases due to the released heat of adsorption. Desiccant coated heat exchangers overcome this limitation. Such heat exchangers are able to deliver combined heat and mass transfer between the process air and the working fluid. The process air can be cooled and dehumidified simultaneously by pumping cooling water/refrigerant in the desiccant coated heat exchanger. The desiccant coated heat exchanger has to be heated cyclically to regenerate the desiccant material. This article presents a review on the studies conducted on air-to-liquid desiccant coated heat exchangers. It summarizes various modeling approaches used to simulate the performance of desiccant coated heat exchangers as well as the experimental studies conducted to validate these models. It also reviews the current and potential applications of these heat exchangers. Current work in this field consists of experiments conducted on desiccant coated heat exchangers as standalone equipment (i.e. component level) as well as an integrated component into cooling and dehumidification systems (system level). The integration of desiccant coated heat exchangers in such systems was found to improve the coefficient of performance, leading to energy savings.