Haze particles removal and thermally induced membrane dehumidification system

Air conditioning systems consume a large portion of energy to remove the latent heat of moisture to reach the indoor comfort level in Southeast Asia due to the high relative humidity. The worsening air pollution causes significant health concerns in recent years. Therefore, an efficient strategy to simultaneously remove both haze particles and excess humidity is very important, particularly for large buildings. In this study, a thermally induced membrane dehumidification system was established by using waste energy to create a partial pressure difference of water vapor across the membrane to reduce the excess humidity. A pilot scale system test showed that the removal of water vapor was a function of hot plate temperature and up to 12.4% of water vapor could be effectively removed by using a merely 0.55 m2 polytetrafluoroethylene - polydimethylsiloxane (PTFE-PDMS) flat membrane with the aid of an air blower at a pressure of 8.54 mbar. As a result, the inlet air with a water vapor concentration of 24.3 ± 0.5 g/m3 dropped to 21.3 ± 0.5 g/m3 after the dehumidification. The calculated energy saving in this dehumidification process was about 10.8% with ΔE = 93.0 kJ/h. In addition, the newly developed stacked polypropylene - polydimethylsiloxane (PP-PDMS) filter showed the particle removal efficiency up to 98.2% with a very minimal pressure loss of 0.18 mbar.