Research on the Effect of Wind Pressure Ventilation of Office Buildings
|Course||Heating,Gas Supply, Ventilation and Air Conditioning Engineering|
|Keywords||Office Building Wind Pressure driven Ventilation Ventilation Effect Mutizone Network Model CFD|
As a passive method in reducing building operation energy consumption and improving residential environment, natural ventilation not only can eliminate wast heat and moisture to meet human thermal comfort requirement, but also can provide with fresh air to satisfy psychological needs in communication with nature. According to dynamic difference, natural ventilation is divided into wind pressure driven ventilation and stack ventilation. Cross ventilation, which is commonly refered, is the process of air exchange across the interior of building driven by wind pressure. This paper studies the wind pressure ventilation effect of different layout forms of office building, and proposes the optimizing natural ventilation design scheme for different layout forms of office building, so as to realize the purpose of guiding for the architects’natural ventilation design.Based on the existing research results, this paper determines the index for the evaluation of air pressure ventilation effect from the aspects of natural ventilation rates and indoor air flow field. And among them, for the indoor air flow field, basen on human thermal comfort, this paper divides indoor wind speed into comfortable, acceptable and unacceptable division with the range of comfortable temperature for natural ventilation as follows: 1) Acceptable wind speed is 0.15m/s to 0.8m/s, while comfortable division is 0.15m/s to 0.5m/s; 2) Unacceptable wind speed is below 0.15m/s and above 0.8m/s. Then two methods for the evaluation of air pressure ventilation effect are studied in the paper. With the No.2 office building in one R&D center as research object, by analyzing indoor and outdoor wind speed variation law with time, this paper proposes the determination method for data sampling time of measured mean value, and finally forms the measuring method for evaluating wind pressure ventilation effect in office building. Meanwhile, basen on the mutizone network model and CFD method, the simulation method is also proposed in the paper. Furthermore, applied with the measuring and simulation method, this paper studies the air pressure ventilation of the 4th floor of No.2 office building in one R&D center. And with the comparation of measured and simulated value, the consistency of the two methods is verified. Finally, based on the typical layouts of office building in the common used standard Architectural design data set - Volume Four, from the aspects of air pressure ventilation, the layout of office building is classified renewedly in the paper. With the method of mutizone network model and CFD simulation, by the different wind of north-west, west-north-west, north-north-west and north, natural ventilation rate and indoor air flow field in the rooms of different layouts of office building are calculated seperatively. And the results are analyzed with the wind pressure effect evaluation index of natural ventilation rate and indoor air flow field. Then from the aspects of relative position between outdoor wind direction and indoors of the building, angle relationship between outdoor wind direction and normal direction of building, and relative position between the large bay and small bay office, this paper proposes the optimizing natural ventilation design scheme for different layout forms of office building, and guides for the architects’natural ventilation design.