Performance Evaluation of Electrostatically Augmented Air Filters Coupled with a Corona Precharger

Abstract

An experimental study of electrostatically augmented air (EAA) lters coupled with a corona precharger has been conducted using Arizona road dusts and tobacco smoke. The measurements of lter ef ciency and pressure drop across the EAA lter have been made using an ASHRAE 52.1-1992 lter test system and an opacity meter to measure the particle concentration upstream and downstream of the test lter. The two-stage EAA lter unit consists of the positive corona precharger upstream of a lter, to precharge particles with the electrical strength of 4.7 kV/cm, and an electri ed lter collector, which has folded media with meshy metal separators, in the upstream and downstream side gaps. DC voltage of + 1,000 V (1.4 kV/cm) is applied between the upstream and downstream separators to produce an electric eld between the separators and media as well as across the media in a polarity so that most of the precharged particulates are collected on the upstream lter collector. A conventional lter was measured and had 70.0% ef ciency with dusts of 1.96 ¹m in mass median diameter and 2.5 m/s face velocity, while the EAA lter had 92.9% ef ciency. An electrical effect on the EAA lter was evaluated to both improve the lter ef ciency and reduce the pressure drop across the lter. Also, the performance evaluation of the EAA lter using an air handling chamber system in occupied space was investigated with tobacco smoke particles.

Removal of PM2.5 entering through the ventilation duct in an automobile using a carbon fiber ionizer-assisted cabin air filter

“…One example of a traditional particle charging system is that of corona discharge (Qi, Chen, & Pui, 2007;Unger, Boulaud, & Borra, 2004). To investigate this system, Lee et al (2001) carried out an experimental study involving electret filters coupled with a corona pre-charger.…”

Al-Coated Conductive Fiber Filters for High-Efficiency Electrostatic Filtration: Effects of Electrical and Fiber Structural Properties

“…Numerous electrostatic filtration characteristics regarding particle penetration, particle loading behavior, and the effects of the physical and electrical properties of the particles, for instance, have been analyzed 11 – 13 . However, these studies focused mainly on nonconductive filters electrostatically reinforced by charge injection 23 , 24 and/or by the polarization of filter fibers under external electric fields 25 – 27 . Although there have been several conductive filters consisting of a stainless steel (SUS) mesh 28 and silver nanowire percolation network 29 , the effects of the electrical and structural properties of conductive filter media have yet to be examined with regard to the electrostatic filtration performance capabilities.…”

Application of corona discharge-generated air ions for filtration of aerosolized virus and inactivation of filtered virus

“…A charged particle in such a nonuniform electric field experiences a force, in addition to the force exerted by the externally applied field (Wang, 2011). Lee, Kim, Shin, Lee, Ku, and Shin (2011) evaluated the performance of a two-stage electrostatically augmented air filter consisting of a positive corona precharger located upstream of the filter and an electrified filter collector coupled with an external electrical field. Kim, Sioutas, and Chang (2000) utilized a stainless-steel fibrous filter as the ground electrode of a point-toplate electrostatic precipitator so that the particle-laden flow passed through the filter.…”