Pollutant distribution study of the 2-fan enhanced displacement ventilation system in the tropics

Abstract

novel idea of bringing cooler air near the floor level upward via 2 fans mounted on both sides of a chair was developed to enhance the performance of the conventional displacement ventilation (DV) system in small spaces with low heat load and floor-to-ceiling height. The pollutant's transportation study was designed to investigate the impact of the use of fan on the vertical distribution of local pollutant within the breathing zone of the breathing thermal manikin in the room and the impact of different pollutant sources on the pollutant transportation. The impact of the airflow induced by the fans was studied by means of tracer gas technique. The tracer gas used in this study is sulfur hexafluoride, SF6. The concentration of SF6 in the breathing zone emitted by the plane and point sources are measured respectively. The results showed that the use of fans increased the concentration of pollutant around the manikin, thus reduced the air quality around the manikin when there are polluting source in front of the manikin at the desk in the room. The result also showed that the concentration of SF6 is affected by room air temperature. With the same discharge angle of fans or without fan, the concentration of pollutant increases with the increase of room air temperature. With the same emission rate of tracer gas from both the point and plane sources, the concentration of pollutant in the inhaled air is higher for the plane source than the point source.