Abstract: An air filtration system includable in and for HVAC equipment includes one or more intense field dielectric filter units and a field charging unit retained in a support structure or cabinet by a removable door which includes control circuitry and contactors engageable with corresponding contact members on a filter unit and the field charging unit for supplying high voltage DC potential to the respective units. Each filter unit includes a filter core comprising a stacked array of filter elements formed of dielectric sheets interconnected by elongated spaced apart ribs forming flow passages. The field charging unit and the filter units are removable from the support or cabinet for cleaning or replacement by opening or removing the door. An interlock switch and a field shorting mechanism are actuated during servicing or replacement of the system components.

Abstract: A centrifugal blower for a furnace, heat pump, or other type of air handling unit includes a heat-generating blower housing that heats the airflow as the air passes through the blower housing. In some cases, the housing is made of a thermosetting resin impregnated with graphite or co-molded with a graphite cloth. Heat is generated within the housing wall by applying voltage across the housing.