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New Solar-Powered Device Can Pull Water Straight From the Desert Air (sciencemag.org)
sciencehabit quotes a report from Science Magazine: You can't squeeze blood from a stone, but wringing water from the desert sky is now possible, thanks to a new spongelike device that uses sunlight to suck water vapor from air, even in low humidity. The device can produce nearly 3 liters of water per day, and researchers say future versions will be even better. That means homes in the driest parts of the world could soon have a solar-powered appliance capable of delivering all the water they need, offering relief to billions of people. To find an all-purpose solution, researchers led by Omar Yaghi, a chemist at the University of California, Berkeley, turned to a family of crystalline powders called metal organic frameworks, or MOFs. Yaghi developed the first MOFs -- porous crystals that form continuous 3D networks -- more than 20 years ago. The networks assemble in a Tinkertoy-like fashion from metal atoms that act as the hubs and sticklike organic compounds that link the hubs together. By choosing different metals and organics, chemists can dial in the properties of each MOF, controlling what gases bind to them, and how strongly they hold on. The system Wang and her students designed consists of a kilogram of dust-sized MOF crystals pressed into a thin sheet of porous copper metal. That sheet is placed between a solar absorber and a condenser plate and positioned inside a chamber. At night the chamber is opened, allowing ambient air to diffuse through the porous MOF and water molecules to stick to its interior surfaces, gathering in groups of eight to form tiny cubic droplets. In the morning, the chamber is closed, and sunlight entering through a window on top of the device then heats up the MOF, which liberates the water droplets and drives them -- as vapor -- toward the cooler condenser. The temperature difference, as well as the high humidity inside the chamber, causes the vapor to condense as liquid water, which drips into a collector. The findings were published in the journal Science.
Sounds a bit like a windtrap. Can sietchs and spice-harvesting be far off?
There have been a few, let's say, shady promises about extracting water from air, mostly coupled with crowdfunding campaigns (gee, why could that be?). Those that actually delivered a product were mostly ridiculous, provided you were not one of those duped into backing it. Then it was more a reason for anger and disappointment.
Most actually never delivered. Which reminds me, wasn't Fontus due to deliver right now in April? Any backers here, did they actually deliver? Because, let's put it careful, I'd really, really love to see that!
So don't get me wrong when I don't hold my breath. I have been promised easy water from thin air before. And what has been delivered so far, if anything, was ridiculous. Either it didn't work, didn't scale past proof-of-concept scale or only worked if the humidity was high enough that rain was more the rule than the exception, rendering a system that extracts water from the air redundant: A bucket would do.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Who on earth is so stupid to believe that "a billion" people live in "deserts"?
How about the United Nations? Strictly speaking it isn't all desert but apparently well north of a billion people live in water stressed parts of the world or areas threatened by desertification.
Nevertheless a device like this might be useful in all warm/humid areas.
Maybe. The real question is how much does it cost per unit of water generated. To be useful it would have to generate a rather sizeable amount of water even to just cover drinking and basic cleaning needs.
...that really is VAPOR ware. ;)
They are doing some sort of magic with exotic materials that concentrate water vapor in the air prior to the condensation.
> I assume the water it produces is akin to distilled water. Isn't that bad to drink?
Yes. A lot of the human digestive tract works by osmosis. Putting distilled water through it means it's going to reverse, and rather than your body absorbing a lot of important things, it's going to be dumping them - presumably into your stool.
I don't imagine hardening water to healthy levels will be all that difficult... the question is, can you make it inexpensive, robust, and foolproof enough for the type of applications this device (if it works and is practical) would see.
Continual consumption of distilled water is bad for your heart, nervous system, and immune system - but it takes fair while, and there are other ways to get minerals and other things you might normally get from water... mainly *eating* them. Still, it would be an additional concern that you otherwise wouldn't even have to think about.