Shading of faqade solar collectors has been investigated for two basic block of flats types usual in urban housing estates: row buildings and tower buildings. Shading analysis has been performed in simulation software ESP-r, which allows energy balances including the shading by surrounding objects (isotropic radiation model used). Climatic database for Prague (Czech Republic) in the form of test reference year has been used as a source of solar irradiation data. Albedo of the terrain surface has been considered 0.2. Annual solar irradiation qs [kWh/m2.a] of south oriented faqade located at shaded object has been obtained from simulations in dependence on distance and height of surrounding shading objects. Annual solar irradiation of faqade without any shading (maximum value) is qs = 749 kWh/m2.a for given climatic database.

For the row building, the building with the same ground plan (length 50 m, width 10 m) has been considered as the shading object. Distance as [m] and height of shading building hs [m] with respect to height of shaded building h [m] were the variables. Simulation analysis has been performed with distance range from 3 to 50 m and buildings height range from 3 to 24 m (eight floor building). Geometry and parameters for the row building case are outlined in Fig. 2 (left).

Three shading objects with identical ground plan (20 x 20 m) as the shaded one have been considered in the tower building case. Height of both shaded and shading buildings has been used equal and varied from 3 to 24 m. Distance as of shading objects from shaded one and mutual distance between shading objects bs were the variables and both ranged from 3 to 50 m. Geometry and parameters for the tower building case are outlined in Fig. 2 (right).

1.1. Results

Shading of row building in housing estate has been modelled for large number of relationships between shaded and shading buildings in distance and height values. Annual irradiation levels incident on the south facade qs [kWh/m2] dependent on ratio of shaded building height h and its distance as from shading building with the height hs have been obtained. Three sets of results represent different height ratio hs/h between shading and shaded building. Fig. 3 (left) shows the dependence of facade irradiation qs and its percentual reduction on h/as ratio for different height parameter hs/h (values 0.5; 1.0; 2.0). It is evident that influence of shading can be neglected for low values of h/as < 0.5, eventually for low values of hs/h < 0.5.

Shading of tower building in the housing estate has been modelled in similar way to row building case. The ratio between shading and shaded building hs/h =1 has been considered. Besides the influence of distance as between shading buildings and shaded building the influence of mutual distance bs between shading buildings has been investigated. Three sets of results have been obtained for different distance bs values (3; 10; 50 m). Curves qs = f (h/as) are shown in Fig. 3 (right) together with percentual reduction figures. Similar to row building case, influence of shading can be neglected for low values of h/as < 0.5. Shape of curves for different distance bs values are not changing significantly.