Cyclic operation of a membrane-based vacuum dehumidification system by finite selectivity of the membrane

Water vapor can be selectively separated from humid indoor air using membrane-based vacuum dehumidification (MVD). This non-vapor compression dehumidification system is an alternative to conventional air conditioning systems because water vapor separation through the membrane is an isothermal process. Some researchers have analyzed the dehumidification performance of MVD and proposed the most efficient structure for a membrane with infinite selectivity. In this study, finite selectivity was considered, and an additional vacuum pump was installed on the basic MVD structure. The cyclic operation performance of the revised MVD was calculated and optimized according to the vacuum compressor performance. Consequently, the cyclic average dehumidification COP was maximized on a specific compression ratio. The higher the water vapor selectivity, the higher the maximum values, and the lower the marginal compression ratio.