Dust loading performance of a non-electret HVAC filter module in the presence of an external electric field

An electret filter composed of electrically charged fibers exhibits high efficiency, while maintaining a low pressure drop. Therefore, the electret filter is used in heating, ventilation, and air-conditioning (HVAC) systems. However, charges on the fiber can be shielded or neutralized by collected dust particles, degrading the collection efficiency of the electret filter. Alternatively, non-electret (mechanical) filters can also be used in HVAC systems. In this study, an external electric field of 5 kV/cm was applied to a non-electret filter module used in HVAC systems to investigate the effect of dust loading on filtration performance. The pressure drop with dust loading less increased in the presence of the electric field than in the absence of the electric field, resulting in a higher dust holding capacity of the filter module. The electric field significantly affected not only the pressure drop but also the collection efficiency. The initial collection efficiency of the filter module was increased by the electric field. In addition, the electric field continuously increased the collection efficiency of the HVAC filter module under dust loading.