Numerical Simulation And Experimental Study On Thermal Channel Of Solar Induced Ventilation

Solar induced natural ventilation utilizes solar heat to heat up the air in thermal channel of building. It forms thermal pressure in internal and external building openings to induce air flow in thermal channel. Natural ventilation can improve indoor thermal environment and human body comfort, reduce building energy consumption. Research in this field has become a widespread concern. To sum up previous studies, solar radiation intensity was added to the model as the form of constant load. The effect of solar radiation, wind environment outdoor and other factors was neglected. Therefore it is necessary to study solar induced natural ventilation systemically.In this paper, on the basis of studies by the scholars at home and aboard, according to summer climate of hot summer and cold winter zone in China, natural ventilation of solar chimney, double glazed facades and Trombe wall in thermal channel is simulated by using FLUENT software and RNG k ?εmodel. The results show that: natural ventilation rate of thermal channel increases with solar radiation intensity. For thermal channel of solar induced ventilation, there are optimum thermal channel width and inlet-outlet vent height to achieve the best effect of natural ventilation. The thermal channel width of solar chimney is 0.1m～0.8m, the optimum width is 0.6m. The thermal channel width of double glazed facades and Trombe wall is 0.1m～0.8m, inlet and outlet vent height is 0.1m～0.7m, the optimum width and height are 0.2m～0.4m.Based on the results of numerical simulation, the experimental solar-induced natural ventilation house is designed and set up. Thermal channel of solar chimney and double glazed facades was studied under outdoor environment condition. The results show that: within the range of this experimental study, natural ventilation rate of thermal channel increases with solar radiation intensity, thermal channel width and inlet-outlet vent height respectively. When thermal channel width of solar chimney is 0.2m～0.7m, natural ventilation rate is 0.1kg/s～0.7kg/s; When thermal channel width of double glazed facades is 0.1m～0.7m, inlet-outlet vent height is0.1m～0.5m. natural ventilation rate is 0.05kg/s～0.4kg/s. For thermal channel of solar induced ventilation, there are optimum thermal channel width and inlet-outlet vent height to achieve the best effect of natural ventilation. Thermal channel width of solar chimney and double glazed facades is 0.1m～0.7m, the optimum width is 0.7m; inlet and outlet vent height of double glazed facades is 0.1m～0.5m, the optimum height is 0.5m. But air temperature is too high in thermal channel when thermal channel is less than 0.4m; this should be avoided in architectural design. By comparing the results of numerical simulation and experimental test, it is find out that the natural ventilation rate of experimental measurement in thermal channel is more than simulation results because of the effect of wind environment outdoor. Therefore, the effect of wind environment outdoor should be considered in architectural design of practical engineering.The results of this subject provide theoretical basis for the application of thermal channel of solar-induced natural ventilation in energy saving building, and it is very valuable design basis of architectural design.