Passive radiative cooling reduces rooftop heat accumulation by reflecting solar radiation and emitting thermal energy through the atmospheric infrared window.
SkyRad združuje visok odboj sončnega sevanja z oddajanjem toplote skozi atmosfersko okno 8–13 μm — območje valovnih dolžin, kjer lahko toplota uhaja proti hladnemu nebu.
The roof must do two things simultaneously: reflect incoming solar radiation and emit its own thermal energy in the mid-infrared band.
At specific infrared wavelengths, the atmosphere is relatively transparent. This allows thermal radiation from engineered surfaces to move outward rather than being trapped near the building.
Ordinary white coatings reflect visible light, but a radiative cooling surface must also emit strongly in the mid-infrared. The combination of reflectance and emissivity is what creates passive cooling potential.