Field synergy analysis on heat and moisture transfer processes of desiccant coated heat exchanger

Abstract

The theoretical analysis of the field synergy is tried to apply to desiccant coated heat exchangers (DCHEs) to clarify its coupled heat and moisture transfer characteristics and the way to enhance the characteristics. In this paper, the heat and moisture transfer model of DFHE is established and verified by comparison with experimental data. Three field synergy angles between temperature gradient, velocity vectorand moisture gradient are introduced and calculated for different types of DFHEs with different air velocities. Through the analysis, the field synergy method is proved available for analysing the coupled heat and mass transfer process of DCHE. Different heat and mass transfer performance index of different structure sizes of DFHEs are analysed. By comparing the sensible heating capacity, dehumidification capacity, Re and field synergy angles of them, the optimization design direction of structure size is obtained. The DFHE with higher ratio between total transfer area and total volume is proved to display better performances. So by optimazing the types of DCHE, DMHE is introduced, and the superiority of DMHE is proved. And the reason why DMHE presents higher heat and mass transfer capacity is illustrated.