Studying the performance of a pilot scale vacuum-based membrane dehumidifier

Research on vacuum-based membrane dehumidification (VMD) has gained significant traction due to it being an efficient isothermal and eco-friendly process. However, most research works are focused on studying well-defined lab-scale membrane dehumidifiers. Therefore, key results on larger-size membrane dehumidifiers are far and few. In this work, a large-scale pilot-scale vacuum membrane prototype is developed and tested for the purpose of achieving high-performing air dehumidification in tropical climate conditions. The membrane prototype comprises 78 m2 of a flat-sheet composite membrane which possesses a high water vapor permeance and selectivity. It is able to remove 25 kg/h of water vapor from input humid air with a dehumidification COP of 2. This COP is much higher than that of a conventional desiccant dehumidifier and reaches 85% of the theoretical COP limit of a single stage pumping vacuum membrane dehumidifier. It is expected that a dehumidification COP of up to 16 can be achieved when this membrane prototype is coupled with a pumping-condensing system with high operating efficacy. The developed VMD system has highly stable performance in 8-week operation test.