High-albedo roof coatings for reducing building cooling needs

This chapter gives a critical analysis of high-albedo coatings for building applications, i.e., cool roofing systems. After a brief introduction concerning the threefold benefits of such applications, i.e., at building, urban, and global climate scale, specific characteristics of these coatings are discussed. The physical properties determining their cooling potential, i.e., solar reflectance, thermal emittance, and the final overall solar reflectance index, are presented. In Section 9.3, the thermal-energy behavior of a roof is assessed. Section 9.4 details the methodology for measuring solar reflectance and infrared emittance and references technical standards. In Section 9.5, the benefits of high-albedo coatings for roofs are presented. Section 9.6 concerns new scientific trends in high-albedo materials. Finally, aging and weathering phenomena are discussed. The analysis of these aspects is supported by experimental, analytic, and numerical data reported in the reference section.