Analysis and optimization of material physical characteristics for electrolytic air dehumidifier with a PEM

Abstract

Electrolytic dehumidification based on polymer electrolyte membrane (PEM) has the advantages of environment-friendly, compact structure and convenient operation. Thermal and economic performance of this dehumidifier are closely related to its material characteristics, while most previous studies focused on the effects of operation parameters. In this paper, using a 2-D steady-state model solved by the finite difference method, the influences of various material physical characteristics within the dehumidification module on dehumidification performance (dehumidification rate, operating current, mass transfer/electrical resistance and cost) have been investigated. Results showed that the CLA’s (anode catalyst layers) physical characteristics has great effect on the moisture removal rate, followed by PEM’s, and the smallest was DLA’s (anode diffusion layers). When the CLA tortuosity doubled, the removal rate enhanced by about 85%, while the rate changed hardly with the change of the DLC (cathode diffusion layers)and CLC (cathode catalyst layers). Furthermore, the mass transfer resistance changed significantly with the CLA material characteristics, while the electrical resistance mainly changed with the thickness of PEM. Then, optimization was conducted by the genetic algorithm (GA), to obtain optimal material parameters for optimized thermal and economic performance. It is found that the optimization of CLA materials is the key to improve the dehumidification rate, such as properly increasing the tortuosity or thickness and decreasing the porosity or pore diameter. The research provided a theoretical basis and practical guidelines for system optimization, which helps the research and engineering of electrolytic dehumidifier with a PEM.