Roof paint blocks 97% of sunlight and pulls water from the air: Researchers created a nano-engineered polymer coating that not only reflects up to 97% of the sun’s rays, but also passively collects water, generating as much as 390 mL of water per square meter and indoors up to 6 °C (~11 °F) cooler.
https://newatlas.com/materials/roof-paint-blocks-sunlight-collects-water/
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**This roof paint blocks 97% of sunlight and pulls water from the air**
A roof paint that can cool your home and pull fresh water straight out of the air? It’s within reach, as scientists scale up production of a new kind of paint-like coating that shields roofing from the sun’s rays and harvests dew from its surface.
**Researchers at the University of Sydney and commercial start-up Dewpoint Innovations have created a nano-engineered polymer coating that not only reflects up to 97% of the sun’s rays, but also passively collects water. In tests, it was able to keep indoors up to 6 °C (~11 °F) cooler than the air outside**.
That temperature differential results in water vapor condensing on the surface – like the fogging on a cold mirror – producing a steady trickle of droplets.
In trials on the roof of the Sydney Nanoscience Hub, the coating captured dew more than 30% of the year, **generating as much as 390 mL of water per square meter (roughly 13 fluid ounces per 10.8 square feet) daily**. This might not sound like a lot, but a 12-sq-m (about 129-sq-ft) section of treated roof could produce around 4.7 L (around 1.25 US gallons) of water per day under optimal conditions.
For those interested, here’s the link to the peer reviewed journal article:
https://advanced.onlinelibrary.wiley.com/doi/10.1002/adfm.202519108
Ok, so there are two requirements.
> 1. coatings is reported with ultra-high total solar reflectance (96%) and emittance (95% in the atmospheric window), which can passively cool 6°C below ambient temperature when exposed to the sky, even under direct sun.
This means there is no haze, or cloud cover. This is because to reach this extremaly high emittance, you need to “emit” to space. And clouds, water vapour etc will reabsorb and reflect energy.
> 2. which can passively cool 6°C below ambient temperature when exposed to the sky, even under direct sun. When the coating cools below the dew point, it harvests water from the atmosphere through condensation of droplets.
It looks interesting but on the other hand – hot, high humidity areas often have enough water 😉
Does it come with some type of “dirt” remover as well? Seems like pollution would accumulate on the surface as well.