Experimental study of a compact electrostatically assisted air coarse filter for efficient particle removal: Synergistic particle charging and filter polarizing

Publication date: Available online 2 March 2018
Source:Building and Environment
Author(s): Enze Tian, Jinhan Mo, Zhengwei Long, Haiyun Luo, Yinping Zhang
Efficient particle removal technology with minimal pressure drop is urgently needed for both air purification and energy conservation. We developed a compact Electrostatically Assisted Air (cEAA) coarse filter, whose particle removal performance is enhanced by the synergistic effect of a corona charging field and a polarizing field. We investigated the influences of charging voltage (U), polarizing distance (d pl ), effect of dielectric and geometric characteristics of the filter material on fraction filtration efficiency of PM0.01∼5, net ozone production, pressure drop and power dissipation of the cEAA coarse filter. Our experiments were performed in a ventilation duct using ambient air particulate matter. We found an optimal U between the corona charging onset voltage and the polarizing onset voltage that enhances particle filtration efficiency with nearly no net ozone production and low energy consumption. Single pass filtration efficiency for 0.3 μm particles increased from 4% to 69% with U varying from 0 to +9 kV (d pl  = 3.5 cm). We found that filter material of larger relative dielectric constant or larger tortuosity yields higher filtration efficiencies. During a 458-h long-term operating period, the single pass filtration efficiency of the cEAA coarse filter did not decrease but increased slightly, and the pressure drop grew from 14.3 Pa to 31.5 Pa. We present a design strategy for a cEAA coarse filter with less than 30 Pa pressure drop at 1 m/s air velocity.

Graphical abstract