Study on the Degree and Mechanism of Solar Shading Impacts from Rooftop Structures in the Solar Collector Layout Area

The authors defined four physical quantities’ shading rates, namely the time integral of insolation area, the direct solar radiation, the diffuse solar radiation, and the incident solar radiation. Taking a practical project’s roof in western Sichuan as an object, this paper studied shading rates from roof structures on the solar collector layout area in the heating season and quantified shading impacts from different time dimensions. The results show that shading rates are maximum in the coldest month, December, and that is smaller in the early and late of the heating season. In December, shading rates of the time integral of insolation area and the incident solar radiation are 53% and 30%, respectively, which indicate that shading effects of roof structures cannot be ignored in the heating system design. The research results are of great reference value for the installation optimization of collectors and the reasonable matching of the heating system.