Study on the dehumidification performance of vacuum membrane-based dehumidification modules with convex membrane characteristics

Abstract

Vacuum membrane-based dehumidification technology is one of the key technologies of the next-generation air conditioning system. This work proposes a method for actively constructing convex vacuum membrane-based dehumidification modules by internal fins. A numerical model of internal finned vacuum membrane-based dehumidification is developed and validated experimentally. The dehumidifying and flowing characteristics of two different convex vacuum membrane-based dehumidification modules with internal spiral fins and internal straight fins are comparatively studied. Moreover, the mechanism behind the different dehumidification phenomena is revealed by the concentration and velocity fields. In addition, the effect of the characteristic angle of fins and twist number on the performance of dehumidifying and flowing are analyzed. The results show that the dehumidification performance of the internal spiral finned vacuum membrane-based dehumidification module is weaker than that of the internal straight finned vacuum membrane-based dehumidification module, and the flowing resistance of the internal spiral finned vacuum membrane-based dehumidification module is higher than that of the internal straight finned vacuum membrane-based dehumidification module. Apart from this, the internal spiral finned vacuum membrane-based dehumidification modules cause the direction of moist air to change in some regions, which lead to single-peaked, bimodal, or multi-peaked distribution of humidity ratio under different characteristic angle. Considering the dehumidification effect and flow resistance, the straight finned vacuum membrane-based dehumidification module is more recommended as a vacuum membrane-based dehumidification module with convex membrane characteristics in engineering. This work can provide a reference for the diversified development and some new insights into the mass transfer of vacuum membrane dehumidification modules.