Numerical analysis on heat and mass transfer of the planar membrane dehumidifier

The ambient air with the excessive moisture needs to be dehumidified for a comfortable environment using air conditioning. The planar membrane-based dehumidifier (PMD) is a potential technology to remove moisture in humid air. The performance of PMDs with different operating conditions is evaluated via numerical simulations with focuses on influences of the flow channel geometry, i.e. aspect ratio (AR) of width over height, on the dehumidification performance firstly. The result discloses channels with AR = 2 have the best coefficient of performance (COP). Thus, three-dimensional dehumidifiers are simulated to further understand the physical mechanism of air dehumidification. Finally, an in-depth parametric analysis is carried out with emphasis on the influence of governing parameters on PMD performances, such as dehumidification rate (DR), dew point approach temperature (DPAT), pressure drop (ΔP), and COP. The results show that enhancing mass flow rates leads to an ascending tendency of DR, DPAT, and ΔP, but a descending tendency of COP. Increasing the inlet temperature of dry side results in the reduction of both DR and DPAT, but the increase in ΔP, resulting in the deterioration of the COP. Additionally, the counterflow PMD always has better dehumidification performance than parallel one for various governing parameters.