Nature Ventilation For Double-skin Fa Ade

In recent years, the architects have a great deal of interest in double-skin facades ( DSF ) due to the advantages claimed for this technology in terms of energy saving, aesthetic, daylight, protection from external noise. Comparing to the traditional glass curtain wall, the double-skin fa?ade is more suite for the change of the climate. It improves the natural ventilation utilized and the indoor thermal environment. This article study how natural ventilation can be utilized in the DSF and the room, 1) when there have no openings between DSF and the room, 2) when there have openings between DSF and room.Firstly, this paper takes the theoretical analysis method to analyses the flow action principle of DSF by the stack effect and the wind pressure, and has established the experience formula of ventilation rate for DSF by stack effect and the out-skin pressure of DSF by wind pressure. Then, experiments have been performed, to a new building with DSF in February and July in Chongqing, which is taken as project case. The results obtained from the experiments and analysis, indicate that there are some design problems for the DSF of the building in winter. At last, simulations have been performed, to the project case. CFD software is used to analyses the flow of the DSF and the room, the indoor air quality. Energyplus is used to analyses the energy consumption of the building without DSF and with DSF.The flow of the DSF is influenced by the outdoor wind direction distribution, outdoor wind speed, the opening of the DSF and the direction of the DSF. According the weather in Chongqing, as for the ventilaton, the best direction for the DSF is northwest. The DSF have good ability for reducing the indoor temperature and controling the indoor temperature, and it can control the indoor temperature to 25℃~30℃for the building with low internal heat, when the outdoor temperature is 37℃. Improving the speed of the flow is not only removing the heat gain of the DSF quickly, but also increase the solar radiation heat gain of the DSF, so that it can reduce the solar radiation heat gain of the room which with the DSF. The opening of the DSF influences the flow of the room and the DSF, but also the air quality of the room, when there have opeenings between DSF and room. The flow of the DSF can be improved by change the opening of the DSF, and the energy consumption of the building with DSF also can be reduced. The stack effect of the DSF and the energy consumption of the building are both influenced by the size of the openings between the DSF and the room.