Numerical Study on Performance of Solar Chimney for Building Ventilation

Abstract

Ventilation is air circulation inside a building. Two main approaches can be applied for building ventilation: (1) a fan is used to drive the airflow, and (2) natural convection due to temperature difference is used to drive the airflow. The cost of electricity on ventilation is significant, especially when it is considered together with space cooling. The second approach can take advantage of the renewable resource such as solar energy to lower energy cost. This paper presents a numerical model to investigate the solar chimney performance. Several configurations of solar chimney are examined in this study to predict the ventilation of the building. The commercial software package, Fluent, is adopted. The effect of solar chimney height, air gap width as well as the brick width is investigated. It is found that the flow rate increases by 100% as the chimney height increases from 1.5 to 3 m, while the air gap width has much smaller influence. It also shows that the solar chimney works for different seasons although the solar radiation changes significantly. In addition, using an unsteady state model, it can be observed that the chimney with 0.3 m thick brick wall can work the whole day even in the night. It is expected that this research can help design the solar chimney in a better way.Copyright © 2012 by ASME