4 ms·
If the goal is to keep buildings cool you don't want your paint to be as reflective as possible in the whole solar spectrum. You want it to have a low reflectiv
by the8472 6y ago
If the goal is to keep buildings cool you don't want your paint to be as reflective as possible in the whole solar spectrum. You want it to have a low reflectivity (thus high absorption/emissivity) in the infrared window[0] where you'll emit more into space than you'll absorb and high reflectivity in the rest of the spectrum.
[0] https://en.wikipedia.org/wiki/Infrared_window https://en.wikipedia.org/wiki/Infrared_window
- com2kid 6y agoBetter article over at https://phys.org/news/2021-04-whitest-hereand-coolest-literally.html https://phys.org/news/2021-04-whitest-hereand-coolest-litera... says that lots of energy saving paints already reflect tons of IR, a large portion of their (incremental!) improvement over previous paints in this area is specifically because they expanded the range of wavelengths that are reflected.
- the8472 6y agoAh, great. Paper with an emissivity graph: https://arxiv.org/abs/2011.01161 https://arxiv.org/abs/2011.01161 Without that you can't really judge the news article.
- ping_pong 6y agoIt won't get reflected back into space. It will get reflected back to us because of the Greenhouse effect, and it will just keep warming us up. We need to have solar panels to convert that into electrical energy.
- citrin_ru 6y agoGreenhouse effect reflects back to us a small fraction of energy, most of reflected light will go into space.