Shading

Shading causes less radiation to reach the collector surface. The positioning decision of the collector may be influenced by anything that can cause shade on the collector surface such as mountain ranges on the horizon, nearby or tall buildings, nearby trees (in particular when carrying leaves during winter), and nearby roof construction. Local fog conditions can also cause a loss in sunlight. Shading should be avoided during the peak sun hours of the day, 9 a.m.–3 p.m.

The loss of incoming radiation due to shading must be taken into account during simulations for calculating the prospective yield and usually involves mapping the obstacles on the horizon and sky in the face of the collector orientation (Figure 2.8).

Causes of shade such as fallen leaves and snow depend on location and climatic conditions and should also be considered.