Novel Models to Estimate In‐Plane Solar Radiation and Optimize Multi‐Row Solar Panels Deployment Under Shading Conditions

ABSTRACT

Methods to evaluate global radiation on the front side of the second row of a solar energy utilization system, accounting for direct shading and view factor masking effects, are developed. First, the atmospheric transmissivity is used for weather type classification to decouple cloud shading and adjacent array shading. Second, based on solar geometry under direct sunlight, the front side of the second row and the ground gap between adjoining rows may be divided into unshaded entirely or partially shaded (sunlit and shadowed areas), and partially or totally shaded. Hay's anisotropic model is applied to estimate diffuse radiation in unshaded areas under partly cloudy and clear conditions, while the isotropic model is used for shaded areas and overcast conditions. Third, the total radiation on the ground gap and the reflected radiation from the rear side of the first row are corrected by view factors, and the direct, diffuse reflected components are added up for that on the second row. Finally, the proposed models are compared with four existing models. Moreover, the relationship between annual incident radiation on the second row and installation parameters such as tilt angle and space factor, is also discussed to maximize the regionally effective incident radiation. Under overcast conditions, the sky factor is not more than 1.1, horizontally positioned solar panels are optimal. When a space factor ranges from 1.2 to 1.5, the annual optimal tilt angle is approximately 10°. When a space factor exceeds 2.0, the shading and masking effects become inconspicuous, and the optimal tilt angle is around 20°, consistent with that of a single row.