1.3M views · Jul 1, 2023 · 40:14 · 5 HN recommenders · 8 mentions · discussed 2023–2026
NightHawkInLight shows how to make radiative sky cooling paint from grocery and hardware store materials, including a novel calcium carbonate microsphere synthesis. The paint can cool a surface below ambient air temperature in direct sunlight without electricity.
Why Hacker News points people here: It comes up whenever radiative cooling coatings are in the news, as a hands-on DIY guide that shows the approach working with household materials.
“Here is a frankly incredible video of how you could make such a paint”HN comment, 2023
“Here is a frankly incredible video of how you could make such a paint”
Incredible video on making such paint, impractical but interesting
Here is a frankly incredible video of how you could make such a paint if you were so inclined. I don't think it's very practical, but the video is very interesting anyways this video
“this video is a great guide”
Guide to making radiative cooling coatings from household materials
If you want to experiment with making your own radiative cooling coatings with easily available, safe materials and common household tools, this video is a great guide: this video
“you can already get decent results with a material that can be prepared at home”
Home-made cooling material that works decently
Weirdly, you can already get decent results with a material that can be prepared at home: this video It doesn't have all the properties necessary to call it paint, but apparently it does the job.
“You might like NightHawkInLight's videos on the topic”
DIY radiative cooling paint experiments
You might like NightHawkInLight's videos on the topic[0] and Tech Ingredients[1] - they've been working on making paint using this technology with an at-home DIY process and experimenting with it. [0] this video [1] link
“there are a couple good videos about it from NightHawkInLight”
One of a couple good videos on passive radiative cooling
It's a thing in from thousands of years ago link and today link for PDRC there are a couple good videos about it from NightHawkInLight link , this video and Tech Ingredients link link
“There's an interesting guide on how to make radiative cooling paint from common ingredients”
Guide to cooling paint from common ingredients with explanation
There's an interesting guide on how to make radiative cooling paint from common ingredients complete with an explanation why it works: this video The catch is that such paint is not particularly robust, much less weatherproof. Beats yogurt I guess, which tends to smell as it turns in sunlight. I have roof windows and was wondering how much I could gain from panels painted like that, but most likely as much as I would using the next best thing - a window sunshade, which I'm using already.
“Do it yourself”
DIY example of sub-ambient cooling surfaces
I want to point out that to optimize for temperature reduction, you want to minimize absorption while maximizing thermal radiation. This says you want the surface to be reflective at wavelengths below some cutoff, but perfectly emissive (that is, black) above that wavelength. (Actually it's a bit more complex, because the atmosphere emits IR in some bands.) Some work on surfaces of this kind have shown promising results, being able to fall below ambient temperature even in full sunlight. Do it yourself: this video
“made a video about a similar coating”
Similar coating using CaCO3
The youtuber NightHawkInLight made a video about a similar coating (he is using CaCO3 whereas this here is using Al2O3) this video It was also discussed here link Would be interesting to know how the performance compares.
