Experimental and Numerical Studies of Solar Chimney for Ventilation in Low Energy Buildings

As an effective way to protect environment and save energy in buildings, passive ventilation method has generated intense interest for improving indoor thermal environment in recent years. Among these passive ventilation solutions, design of solar chimney in buildings is a promising approach for guiding natural ventilation orderly. Many studies about solar chimneys have mainly focused on achieving a better ventilation performance both experimentally and theoretically in ideal condition, whereas experimental studies are mainly focused on small-sized equipment. This research examines the performance of a full-scale solar chimney in a real building in East-ern China. The measured performance is compared with theoretical calculation and numerical simulation. In a solar chimney of 6.2m length, 2.8m width and 0.35m air gap, the experimental results show that air flow rate of 70.6 m3/h~1887.6 m3/h can be achieved during the daytime in the testing day. Comparing measured value with theoretical value, the flow rate is generally lower than the theoretical value. By data analysis, the suggested discharge coefficient Cd of solar energy in real engineering project is 0.51. With the use of this suggested value, the simulation results show that during the transition seasons (from April to October), solar chimney can be used for saving energy with an energy saving rate around 14.5% in Shanghai. It is shown solar chimney is an effective approach to save energy for residential buildings in transition seasons in hot summer and cold winter area in China.