A photographic method to estimate the shading effect of obstructions

A new, simplified photographic method is proposed to estimate the shading effects of obstructions. In spite of the complex mathematical background of the new tool, its practical application is very simple, and only requires the measurements of three angles for each photograph. The proposed method is particularly useful for overcoming the difficulties caused by the need to accurately describe surrounding objects to estimate shading effects. The new method uses the information contained in a picture and allows one to draw daily solar paths directly on the photograph. The procedure is useful to verify the suitability of a generic site for solar exploitation; its main benefit is the simplicity of use and the transparency of the obtained results. This simple method is also particularly suitable to evaluate the technical feasibility of small solar equipment, which would not require complex software to define the daily solar path.

► The solar direct-normal component affected by obstructions was estimated.
► The procedure is able to automatically draw the sun’s paths on a photograph.
► The measurements of three angles for each photograph is required.
► The method overcomes the difficulties caused by the need to draw obstructions.