Effects of the geometrical and operational parameters and alternative outer cover materials on the performance of solar chimney used for natural ventilation

Abstract

The purpose of this paper is to investigate the performance of solar chimney used for natural ventilation of closed enclosure in order to save energy. To achieve this purpose, a mathematical model simulating the performance of solar chimney was developed. The geometrical and operational parameters were considered. These parameters include: incident solar radiation, wind speed, ambient temperature and the dimensions of the solar chimney height, gap and width. Moreover, different chimney cover material were examined. A computer program was developed to solve the governing energy and conservation equations simultaneously. The model results were compared with available published data. There was a good agreement between the present results and the published data.The present study considered the performance of a solar chimney under specified meteorological conditions at Cairo. The results showed that the air change rate per hour (ACH) was significantly depended on the wind speed as well as the dimensions (height, gap and width). The chimney gap, wind speed influenced largely the air flow rate. The effect of chimney height was not significant enough to be cost effective. The results showed that the air change rate per hour (ACH) throughout the year was more than the desired ventilation standards in enclosure space. Using materials other than glass to construct the outside cover of the chimney achieved a higher flow rate than the standards air change rate per hour (ACH). In addition, both the reduction in construction cost and safety are achieved.