Design, development and performance evaluation of a miniature electrostatic precipitator in an indoor environment

Indoor air quality is a major concern in the modern environment. Although various pollutants coexist indoors, particulate matter (PM) is a major health concern. Even though different PM capture technologies are available in market as well as on lab scale, they pose several drawbacks. It was in this regard that electrostatic precipitator (ESP), a widely preferred technology for industrial application but has yet to be explored to that extent in indoor environments could provide multiple benefits in latter. Therefore, a miniature single-wire, single-stage and wire- plate square cross-sectional ESP was designed in laboratory and operated at optimal operating conditions based on theoretical calculations, experimental results as well as computational fluid dynamics (CFD) modelling to obtain maximised capture of PM. Results from study confirmed that designed ESP was capable of capturing various standard aerosols such as sodium chloride, ammonium chloride and magnesium chloride with a total removal efficiency of 99.94 %-99.97 % in wide PM sizes from 10 nm to 800 nm. To simulate performance in a real scenario, experiments were also performed with major indoor PM sources like incense sticks, candle burning and mosquito coils having different particle number distributions and achieved a total PM capture efficiency of 99.24, 99.99 and 99.97 % respectively. Designed ESP also removed ambient air as well as infiltrated PM from outdoors with a total efficiency of 97.87 % and 99.74 % respectively. Additionally, energy consumed/clean air delivery rate (CADR) (0.32 W/(m3/hr)) and emission of by-products like ultrafine particles as well as nitrogen dioxide were found to be comparatively lesser compared to commercial purifiers suggesting its possible applicability in scaling up as an indoor air purifier.