Explain the principle behind a cool roof

The principle of cool roof is to reflect the maximum sunlight and absorb less heat.

Explanation:

A cool roof is designed to reflect the maximum sunlight so that less heat will be absorbed as compared to the standard roof through which it makes the roof cool. They are prepared by the use of higher reflective paints or a sheet covering or the reflective tiles and shingles. Standard roof can go up to 150 degree Fahrenheit or even higher in summer season. It has higher thermal emittance.