A Survey On Tilting Solar Chimney’s Natural Ventilation Enhancement

Solar chimney is a dynamic structure which uses the radiation of solar energy: a pollution-free, nuisance less and most-clean energy that has been widely developed and applied, to strengthen its natural ventilation function. Solar chimney could be divided into 3 types: the Trombe wall type, the vertical type and the tilting type. The tilting type surpasses the other two types in terms of velocity filed and temperature field, and has bigger ventilation volume. Thus, it is regarded as a more ideal ventilation structure.Taking tilting solar chimney as the research objective, this paper makes theoretical analysis about the heat transferring process within the structure, derives from which the calculation formula and the influencing factors of the its ventilation volume.First of all, the ventilation volume is analyzed theoretically, and then it is compared with the result of the Mathur experiment, and the results show that, all other things being equal, under the same chimney sizes: H=3m, W=1m, D=0.5m, the ventilation volume of a tilting solar chimney could increase by up to 11.52% in comparison with that of a vertical solar chimney.And then, different factors that may impact the ventilation volume of tilting solar chimney are simulated with Airpark, and the result indicates that the ideal length of tilting solar chimney should be the one that suits both the size of the room and the cost, because its temperature and the air velocity grow along with its length increase. Usually, the ideal length is 3 meters in Xi’an. Also, the experiment shows that along with the depth increase, tilting solar chimney’s airflow speed increases first and then decreases until the length reaches 0.7m, therefore, the ideal depth of tilting solar chimney should be 0.7m. And in Xi’an area, the ideal dip angle should be 45°.Finally, after the best size of the tilting solar chimney is determined, the inside thermal comfort level of the tilting solar chimney room is testified by Airpark. The result of which reveals that the temperature of the office activity area maintains basically at 26℃ with the wind speed under 0.25-0.30m/s, the PMV ranges from-0.5 to 0.5 and the PPD is under 10%, which means that up to standard thermal comfort level has been achieved in general. The paper includes 71 graphs, 10 tables and refers to 55 books.