Passive daytime radiative cooling

Passive daytime radiative cooling (PDRC)—also called passive radiative cooling, daytime passive radiative cooling, radiative sky cooling, photonic radiative cooling, and terrestrial radiative cooling—is the use of surfaces that are highly reflective and have high thermal emissivity to reduce the temperature of a building or other object. It has been proposed as a method of reducing temperature increases caused by greenhouse gases by reducing the energy needed for air conditioning, reducing the urban heat island effect, and human body temperatures.

Source: Wikipedia — Passive daytime radiative cooling (CC BY-SA 4.0)