CH-24-C096 - Modeling and Simulation of a Desiccant Coated Kirigami-Based Heat Exchanger

Desiccant materials absorb water vapor directly from the air without the need to sensibly cool the air below its dewpoint temperature. This provides promising applications in the heating, ventilation, and air-conditioning (HVAC) to reduce energy consumption required for the air dehumidification process. Desiccant coated heat exchangers (DCHX) integrate desiccant materials onto heat exchangers as a compact implementation of desiccant dehumidification into HVAC systems. Compared with other methods of implementation, DCHXs offer better moisture absorption/desorption kinetics due to the active cooling/heating to the desiccant during the alternating dehumidification and regeneration processes. On the other hand, the coupled heat mass transfer with the absorption/desorption on DCHXs poses a challenging problem of a simulation model capable of describing the simultaneous processes for performance prediction, design, and control optimization. This paper describes the development of a model for a DCHX by combining a physics-based model of a hygroscopic hydrogel with a model of a water-cooled coil unit. The model is used to predict the dehumidification and regeneration performance of both a single-DCHX and a dual-DCHX operation of drying air. The model is also used to investigate the effects of key operation parameters including air flow rate and inlet air humidity.