What if the heat emitted by the sun's rays could be reflected directly back into space by buildings?

The "cooling glass" is waterproof, and resistant to heat and water, ultraviolet rays and dirt, say its creators. It can be applied to a wide range of materials. Photo: AFP

What if the heat emitted by the sun’s rays could be reflected directly back into space? This is the idea behind the passive radiative cooling solution currently being tested by US researchers to reduce the use of air conditioning in buildings.

From cool roofs to solar paint, scientists are stepping up their efforts to develop materials designed to reduce the energy consumption of buildings. Researchers at the University of Maryland, in the United States, recently developed a solution based on “passive radiative cooling”. They developed a microporous coating in the form of a paint, composed of glass particles and aluminum oxide, designed to be applied to the walls or roofs of buildings, or even to road infrastructures.