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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.
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.
So, they hooked a solar cell to a thermoelectric cooling cell. Its the same tech as those USB refrigerators. You can build a basic a basic unit for $30-40.
You say things that offend me and I can deal with it. Can you?
A human only needs around 1l of water a day to survive.
You will respirate and pee away well more than 1 liter per day under normal circumstances even if you aren't in a desert and are doing nothing active. Water requirements can easily exceed that substantially if you are sweating significantly or if it is very hot.
From the first Google search result: "The relative humidity in the Sahara Desert is 25%"
Along with this result: http://www.engineeringtoolbox.com/water-vapor-air-d_854.html - suggests that there is actually MORE TOTAL WATER in the air over the Sahara Desert than there is in the air in most of the continental US at any time of the year.
https://www.youtube.com/watch?...
If solar panel lifetime is shorter than 15-20 years like you say, why do solar manufacturers offer warrantees for 25 years or more? For example, here is LG's warranty page for their solar panels, they guarantee that their panels will produce at least 80.2% of their rated output at the end of the 25th year. Panel lifetimes are certainly better than the "few years" that you claim.
Enigma
Im averaging 14kw per day from a 2kw system with micro inverters. Thats averaging around 1kw. Your system must suck bad.