A methodology for the calculation of solar gain in buildings through selective glazed surfaces for the application of building energy saving

A more accurate calculation methodology is proposed of the total solar energy transmittance g of glazed surfaces based upon the determination of solar factors in visible, infrared and ultraviolet bands. The method uses measured values of solar radiation and spectral optical properties of glazed surfaces calculated with the WIS code. This code implements the calculation procedure of optical parameters of EN 410 Specification, which uses a standard spectral distribution of global solar radiation. The investigation, referring to glazed surfaces with different optical properties, permits the highlighting of solar factor variability in the entire solar band and in the three bands which are characteristic of the spectrum, varying recorded solar energy, and the limits of the Standard procedure which assigns constant values to such coefficients. The results obtained are interesting, above all for the characterisation of glass with different optical properties in infrared and visible bands.