The Applicability Of Ventilation Methods Of The New Ventilation Window In Different Residential Building Space

China had frequently experienced heavy hazy weather in recent years. The concentration of PM2.5 in the air exceeded the standard badly, that harmed to the environment and people’s health. However, the governance of outdoor environment haze cannot be accomplished overnight, and reducing indoor haze and improving indoor air quality are extremely urgent.Residential buildings in China depend on the natural ventilation of opening windows or doors to exchange indoor and outdoor air, but the supply air volume is difficult to control and it is not suitable to open windows for ventilation in hazy weather. Air purification and ventilations are effective approaches for improving indoor air quality. It has been founded that ventilation windows have a great potential for improving indoor air quality. The new ventilation windows proposed in this paper can supply purified fresh air indoor and discharge dirty air outdoor by mechanical supply and exhaust air without opening the window, which can solve the ventilation problem in hazy weather commendably.In this paper, the applicability of ventilation methods of the ventilation window in the residential building space were studied. According to the different combinations of the supply and exhaust air, the ventilation methods of the ventilation window can be divided into ventilation window with air supply only, both-way ventilation window with both air supply and exhaust, and air supply window with exhaust device. Firstly, the improvement of indoor PM2.5 and CO2 concentration with downside air supply of the air supply window and the influence of thermal comfort near the air supply window under different outdoor temperatures were studied through experiments in this paper, and then the applicable properties of the air supply window were obtained, which provided experimental basis for development simulation research of the applicability of ventilation methods of the ventilation window in residential building space. The simulation optimized the supply air methods of the ventilation window and had developing research on the impact of the up air supply, downside air supply, and side air supply of the air supply window; and the downside air supply with downside exhaust, side air supply with side air exhaust and downside air supply with up air exhaust of the both-way ventilation window on improving of indoor air quality. And the air supply window with exhaust device were studied too. By analyzing the indoor air flow field and PM2.5 and CO2 concentration field of nine ventilation methods, the most applicable ventilation method was found in different width and depth of the room.The experimental results indicated that compared with the air supply window off, running the air supply window can effectively improve indoor air quality by decreasing PM2.5concentration of 31%~34% and CO2 concentration of 9%~125%, and the air supply window with air exhaust is better than the way that air supply only. Study on the indoor thermal environment with the air supply window operating indicated that compared with the air supply window off, operating at high grade of the air supply window promoted the air mixture near the window and improved the thermal stratification. Therefore, the supply air volume of the air supply window should be bigger than 25 m3/h.The simulation development research shown that PM2.5 concentration decayed fast in0~60min, reduced more than 33%; And the decays slower in 60~120min. The indoor pollutant concentration exceeded standard seriously without ventilation. The indoor PM2.5concentration decayed at least 46% after running the ventilation windows for 120 mins, and was lower than the secondary standard limit; Compared with that without ventilation,indoor CO2 concentration was reduced 129% at least, which is about 1000 ppm of the prescribed standard. Along the width direction of the room near the ventilation window, the airflow of downside air supply was limited by the interior wall of the room obviously while spreading around, and the improvement effect of indoor air quality was the best. While the depth of the room is less than 3.6m, the air supply window can effectively reduce the pollutant concentration to the standard requirements, and the average concentration of the most unfavorable indoor ventilation area is the lowest with downside air supply of the air supply window. In area where the depth of the room is bigger than 3.6m, after operating the ventilation window 60 mins, PM2.5 concentration in breathing area exceeds the secondary standard and exhausting devices should be combined to increased airflow range. Compared with air supply window, both-way ventilation window has a better effect on improving air quality in area where room depth is bigger than 3.6m, but the air inlet and outlet should not be at the same height to prevent air short circuit. Downside air supply with up air exhaust way should be used and the air inlet height should satisfy that the supply air can reach breathing directly. When the depth of the room is less than 5.7m, downside air supply with opposite up air exhaust method is a proper way, but considering its high cost and the design and installation are difficulty, therefore, when the depth of the room is between 3.6m~5.4m,both-way ventilation window with down air supply with down air exhaust is suggested;When the depth of the room is bigger than 4.5m, downside air supply with opposite up air exhaust method is the optimal way.