Experimental study of the prediction of the ventilation flow rate through solar chimney with large gap-to-height ratios

Abstract

In this study, experiment was carried out with a solar chimney model with large gap-to-height ratios between 0.2 and 0.6. The experimental results show that the existing prediction method available in the literature overpredicts the airflow rate for chimney geometry investigated in this work, especially for vertical solar chimney with large gap-to-height ratios. An improved prediction method, which takes into account the variation of pressure loss coefficient for different flow conditions at the chimney outlet, is presented and compared with the experimental results obtained in this work and available in the literature. It is shown that the improved prediction method are in better agreement with the experiment results than the existing prediction method available in the literature for both narrow and wide chimneys. On the other hand, it is also found that the temperature and velocity distribution of air and airflow rate in chimney are highly dependent on heat flux and chimney gap. Experimental results show that an optimum gap-to-height ratio that maximizes the airflow rate in chimney is around the gap-to-height ratio of 0.5.