This article on the Eco-Intel website investigates a white reflective roof that can significantly reduce the cooling load placed on a commercial building by reducing the solar-heat gain. When a thin-film amorphous-silicon photovoltaic system is installed on such a roof, 85 percent or more of the roof surface may be covered with a product that can have a lower solar reflectance, or SR, than the roof surface. Using United Solar Ovonic’s UNI-SOLAR product as an example, the rated SR coefficient is 0.26. The lower reflectance value results in a higher solar-heat gain and creates a “penalty” in the cooling load of an otherwise cooler roof. However, the PV system is itself converting solar energy into electricity. Read full article