Definition - What does Solar Reflectance mean?
Solar reflectance is the ability of a material to reflect, and not absorb, energy from the sun. Materials with low amounts of solar reflectance will become hot when placed in the sunlight because they absorb its energy. Materials with high amounts of reflectance will not absorb the sunlight and will direct the energy elsewhere.
A material's solar reflectance is an important consideration for the construction, coatings and solar energy industries.
Corrosionpedia explains Solar Reflectance
Solar reflectance is quantified by the solar reflective index (SRI), which uses a scale from 0 to around 100. The lower the number, the lower the amount of solar reflectance that a material has, and therefore it will absorb more solar energy. A pure black surface has a solar reflectance index around 0. A white surface is around 100. A mirrored surface could have a SRI rating of over 100.
Solar reflectance is a very important consideration for the construction industry. If a roof has a low amount of solar reflectance then it will absorb a lot of heat energy from the sun, which in turn makes it more difficult to cool the structure upon which the roof sits.
Knowledge of solar reflectance is also crucial for the energy industry. Solar panels need to absorb light energy; therefore a lower solar reflectance index rating is desired.
Organizations such as the ASTM define methods to determine a material's solar reflectance. Programs such as the Leadership in Energy and Environmental Design (LEED) award certifications for buildings that meet their solar reflectance criteria.