Toward energy saving and high efficiency through an optimized use of a PET coarse filter: The development of a new electrostatically assisted air filter

摘要

Efficient particle removal technology with minimal pressure drop is urgently needed for both air purification and energy conservation. Compact electrostatically assisted air (cEAA) coarse filters can significantly enhance the filtration efficiency of low-efficiency filters without increasing the pressure drop, thus greatly reducing the energy consumption of ventilation fans. In this study, we developed a new structure for an electrostatically assisted air (EM) filter, in which the corona charging and polarizing fields were separated and independently controlled. We experimentally evaluated the influencing factors on both single pass filtration efficiency and energy consumption of 6 EM PET coarse fibrous filters: charging field intensity (E-c), polarizing field intensity (4), and PET filters' characteristics. The EAA filter device increased the single pass filtration efficiency for 0.3-0.5 mu m particles of a PET coarse filter from 0.4% (E-c = E-p =0) to 57.0% (E-c = 5.9 kV/cm, E-p = 0) by particle charging, and then up to 99.0% (E-c = 5.9 kV/cm, E-p = 12.5 kV/cm) by filter polarizing. Increasing E-p enhanced filtration efficiency and reduced power dissipation of EM filters at the same time. Although all filters are made of PET, several filter characteristics - including thickness, filling power, electrostatic half period, morphology and fiber diameter - strongly influence filtration efficiency. We compared the six EM PET filters to traditional filters reported in the literature, and found that to have a more than 90% filtration efficiency for PM0.3-0.5, commercial filters (91.0%) need total power use per unit area (P-t) of at least 327W/m(2), while filters described in the literature (94.1%) need at least Pt = 76W/m(2), and EM PET coarse filters (93.2%) need at least P-t = 39W/m(2). This study gives an understanding of the importance of media optimizing for EM coarse filtration to achieve energy saving and high efficiency. (C) 2019 Elsevier B.V. All rights reserved.