Research On Thermal Multi-Channel Double-Skin Facade

In recent years, more and more attentions have been focused on double-skin facade because of some advantages such as lightness, smartness, briskness and fashion. Compared to the single glazing curtain wall, the double-skin facade has a good property in heat preservation in the winter. When the reasonable height of its opening and shading measures are designed, the double-skin facade also plays a very good effect in heat insulation in the summer. During the transitional season, the natural ventilation through the thermal channel can be adopted to save energy consumption.The three-dimensional CFD methods are employed to analyze the characteristics of multi-channel double-skin facade in the case of the Chengdu climate all year round. The 3-d computational fluid dynamics software was applied to establish the numerical simulation mode of natural ventilation through the thermal channel of double-skin facade under the action of solar radiation and the verification against a set of experiment in related literatures is presented. As a result, the simulated results and the experiment results have a good consistency. This indicates that the numerical methods adopted in this paper can be used to research the natural ventilation through the thermal channel of the double-skin facade.The effects of some factors such as channel height, opening height and channel width on natural ventilation characteristics through double-skin facade thermal channel were researched by 3-d simulation and orthogonal test in summer climate to get the optimization of the thermal channel. By means of the simulation results analysis, we can conclude that the natural ventilation volume from the thermal channel will be increased with the height of thermal channel increasing, but the rate of increase will be decreased in the simulation conditions of this paper. With the opening of inlet and outlet increasing, the ventilation volume of thermal channel will be increased and the average temperature of inner glass will be decreased. The maximum natural ventilation of thermal channel will be obtained when the width of channel is 0.4m. So in this paper, the thermal channel width of 0.4m will be adopted to research the characteristics of multi-channel double-skin facade under the transitional and winter season.According to the optimized results of the summer, the natural ventilation through thermal multi-channel was simulated under transitional season. By means of the comparison of natural ventilation under two difference double-skin facade ventilation modes, it was found that the impact of natural ventilation under the channel exhaust mode is better than the one under the channel inlet mode. Moreover, the better impact of natural ventilation will be achieved through setting up outlet opening location under the channel exhaust mode reasonably that is defined as B-type channel exhaust mode. Therefore, the B-type channel exhaust mode was used to research the characteristics of natural ventilation of multi-channel double-skin facade. In this paper, the natural ventilation conditions were simulated from single thermal channel to four layers thermal multi-channel. Finally, it is found that impact of natural ventilation will reach the best state when the three layers thermal multi-channel was adopted in the simulation conditions of this paper.With the fixed thermal channel width of 0.4m, the heat preservation performance of the thermal multi-channel double-skin facade is calculated and analyzed in winter season. The results show that the temperature of the thermal channel is significantly higher than the outdoor temperature. So the thermal channel plays a good role on the building heat preservation. However, the effect of layers of thermal multi-channel on the temperature at the channel is very small.Some useful conclusions related the thermal multi-channel double-skin facade have been achieved by means of the 3-d simulation researches in this paper. This study can provide some theoretical basis and references for the design of natural ventilation of the thermal multi-channel double-skin facade in engineering practice.