Optimization of the hygrothermal performance of novel metal-organic framework (MOF) based humidity pump: A CFD approach

Solid desiccant humidity pump is an emerging device that enables moisture transport through the inverse gradient of vapor concentration, featuring refrigerant-free, no moveable parts and compact structure. However, traditional materials (e.g. silica gel and zeolite) have made this device less competent due to the poor sorption performance and strict regeneration conditions. In this respect, metal-organic frameworks, representing the cutting edge of the available porous materials, are expected to upgrade the performance of this device. In this study, the optimization of a novel MOF-based humidity pump (MOF-HP) was carried out. We used the CFD method to analyze the hygrothermal performance of a MOF-HP. The model built up the relationship among humid air, desiccant, and heat sink and then coupled the subdomains of the fluid flow, heat transfer, and specie transport. The model of MOF-HP under different operation conditions was validated by experimental tests. Based on the measured results, the discrepancies were maintained under 15%. A parametric optimization was subsequently carried out to enhance the hygrothermal performance of MOF-HP. This dimensional analysis provides some guidelines for MOF-HP design with the most suitable geometry. The optimized configuration is estimated to have a 1.59 times improvement in moisture removal capacity over the original design.