Laboratory scale characterization of cool roof paints: Comparison among different artificial radiation sources

A series of cool coatings realized with three pigments displaying YIn0.9Mn0.1O3-ZnO stoichiometry and different colors (Ochre, Cyan Blue, and Deep Blue) was deposited on AA5005 aluminum substrate. Coatings were investigated by vis/NIR spectrophotometry. The color was evaluated according to CIE-1976L*a*b* method. The innovative approach of this study aims to compare the effectiveness of three different radiation sources (incandescent infrared emitting lamp, tungsten halogen one, and xenon arc one) to properly assess the thermal reflective performance of cool roof coatings. These thermal evaluations were compared with the performances obtained by natural sunlight exposition. In this way was individuated the best sun simulator in terms of temperature and spectral emission, matching NIR reflectance response of the investigated cool roof materials. Considering these two last points the best solar simulator results the xenon arc lamp. Using this radiation source the Deep Blue coating is the best performing coating, as cool surface coating; the other two coatings show promising results.