Nanophotonic Radiative Sky Cooling

Passive daytime radiative cooling is one of the few climate technologies that produces cooling with no electricity, no compressor and no moving parts. A nanostructured coating is engineered at the scale of the infrared wavelength itself so that it reflects almost all incoming sunlight while radiating heat strongly and selectively through the one narrow band — 8 to 13 microns — where Earth's atmosphere is transparent enough to dump that heat directly into the ~3 K of outer space. This simulator models the coupled solar and thermal-infrared energy balance in real time: adjust the coating's solar reflectance and atmospheric-window emissivity, the ambient air temperature, and how strongly wind couples the surface back to the air, and watch the surface settle at its physically correct steady-state temperature — often several degrees below the surrounding air, in full daylight.