On the solar reflectance angular dependence of opaque construction materials and impact on the energy balance of building components

The solar reflectance of the surfaces is a property that varies according to spectral and angular distribution of the incident solar radiation which in turn depends on orientation and latitude. In this paper, an optical characterization was conducted on some typical opaque building materials, generally used as roof covers: shingles, membranes, bricks and tiles. The measurements were carried out through an experimental factory equipped with a large integrating sphere which allows to measure the spectral reflectance at different incidence angles of the light beam on the sample. Thus it was possible to create a function that linked reflectance values with the incidence angle. The results obtained were included within a dynamic software in order to optimize the calculation of solar gains in the energy balance of a building.