Solar collector angle optimization for maximum air flow rate in the solar chimney

Abstract

The solar chimney and the solar collector are two important components in solar energy engineering. Solar collector is mainly used to gather solar energy. Correspondingly, the angle at which the solar collector receives the maximum solar radiation is its core parameter. While for the solar chimney, solar radiation is absorbed by the air inside the solar collector to generate air flow into the chimney. Thus, there is a solar collector tilted angle at which the airflow inside the chimney reaches the maximum. There are many reports on the maximum solar radiation (MSR) in the solar collector. However, there are few studies on the maximum air flow (MAF) in the solar chimney. In this study, a mathematical model is first established for the solar chimney system. Then, an experimental setup is established to evaluate the MAF angle for the solar chimney. The solar chimneys under MSR and MAF angles are finally analyzed and compared. The results mainly show that in solar collector system with MAF angle, with the collector angle increasing, although the air temperature rise decreases gradually at the collector outlet, the air flow rate generally decreases after a long-term increase. And taking the solar radiation at Lanzhou City as a case study, the MAF angle was 60°, whereas the MSR angle was 30°.