Study Of The Indoor Concentration Distribution And Change With The Natural Ventilation By A Heat Source

Natural ventilation technology is a important role to improvement the building energy conservation and indoor air quality and the indoor heat source has a significant impact on the natural ventilation air , so the research on indoor pollutant concentration distribution and change is very urgent and significative.The paper first simulates the concentration distribution in a room being initial contamination and a room being well-distributed pollutant sources and a room be subjected to the outdoor contaminate with natural ventilation by heat source. The results indicate that the concentration distribution in a room being initial contamination is stratification.The concentration distribution in a room being well-distributed pollutant source and a room be subjected to the outdoor contaminate is that the concentration is higher with the heat source than other area of the room. The results also show that higher heat source temperature, the lower indoor average concentration and more uniform to indoor concentration horizontal distribution.At the same times, the paper established a dilution ventilation equationquation base on the thermal natural ventilation through uses existing mathematical model base on thermal natural ventilation. According to the solution of the equation by set a non-dimensional time , it can see that the outdoor concentrations, indoor pollutants, as well as the the window area must meet certain conditions in order to make indoor concentrations to meet attenuation or the different levels of attenuation. The impacts of the heat radiation on the attenuation of indoor concentration are not sufficient while dimensionless area of the window and the height of lower window are more obvious to affect the attenuation of indoor lower region concentration. The displacement ventilation effect more pronounced to the high room as well as the room smaller the window area when stratification height greater than the height of active region.