AN ADVANCED SUPPLY AIR FILTRATION UNIT FOR FILTRATION OF BOTH PARTICLES AND GAS PHASE IMPURITIES

ABSTRACT

Quality of indoor air is affected by several factors, and to reach a satisfying level with respect to air pollutants all the components have to be considered; e.g. not only the particulate pollutants but also odours and harmful gases should be removed from the supply air. With respect to filtration, special attention should also be paid to the fine particles that have been proven to out-number the coarse particles in most environments. We have developed an advanced supply air filtration unit, and evaluated its performance in laboratory and field tests. The filter consists of an electrically enhanced particle filter and an adsorbent filter for gases. The filter has been designed for installation near supply air outlets. In the field tests the filtration efficiency for sub micron particles was over 95% during the whole lifetime of the filter. The removal efficiency of the gas filter for toluene was also high, over 95%. An important advantage is the high efficiency with a low pressure drop that allows the filter to be installed in existing HVAC systems without extensive modifications. With the aid of the filter, protection against harmful or hazardous air contaminants can be improved energy efficiently in specific rooms or areas of a building.