Solar-powered device pulls drinking water straight out of thin air People living in arid, drought-ridden areas may soon be able to get water str...

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Solar-powered device pulls drinking water straight out of thin air People living in arid, drought-ridden areas may soon be able to get water straight from a source that is all around them - the air, US researchers say. Scientists have developed a box that can convert low-humidity air into water, producing several litres every 12 hours, they wrote in the journal Science. "It takes water from the air and it captures it," said Evelyn Wang, a mechanical engineer at the Massachusetts Institute of Technology (MIT) and co-author of the paper. The technology could be "really great for remote areas where there"s really limited infrastructure", she said. The system, which is still in the prototype phase, uses a material that resembles powdery sand to trap air in its tiny pores. When heated by the sun or another source, water molecules in the trapped air are released and condensed, essentially "pulling" the water out of the air, the scientists said. A recent test on a roof at MIT confirmed that the system can produce about a glass of water every hour in 20 to 30 per cent humidity. Companies such as Water-Gen and EcoloBlue already produce atmospheric water-generation units that create water from air. What is special about this new prototype, though, is that it can cultivate water in low-humidity environments using no energy, Wang said. "It doesn't have to be this complicated system that requires some kind refrigeration cycle," she said in an interview with the Thomson Reuters Foundation. An estimated one-third of the world"s population lives in areas with low relative humidity, the scientists said. Areas going through droughts often experience dry air, but Wang said the new product could still help them get access to water. "Now we can get to regions that really are pretty dry, arid regions," she said. "We can provide them with a device, and they can use it pretty simply." The technology opens the door for what co-author Omar Yaghi called "personalised water". Yaghi, a chemistry professor at the University of California, Berkeley, envisions a future where the water is produced off-grid for individual homes and possibly farms using the device. "This application extends beyond drinking water and household purposes, off grid. It opens the way for use of [the technology] to water large regions as in agriculture." In the next few years, Wang said, the developers hope to find a way to reproduce the devices on a large scale and eventually create a formal product. The resulting device, she believes, will be relatively affordable and accessible. Thomson Reuters Foundation As published in the Sydney Morning Herald April 17, 2017 http://www.smh.com.au/environment/solar-powered-device-pulls-drinking-water-straight-out-of-thin-air-20170417-gvm0x4.html

3 Comments

  1. Sir:

    Water from Air systems have been around in one form or another for at least 25 years.

    They work really well in areas where you do not have  a need for them.

    Why ? Because high humidity normally goes with rain.

    If an area is suffering drought and the humidity is low or very low, then these units are pretty well useless....they cost so much to run and produce not really enough water for the amount of energy expended.

    Solar panels, as they are currently produced, do not really make the amounts of energy needed for an extremely large system that would be needed to make adequate water for just a few people.

    Dr. E. Hugh Pettman

     

  2. Dear Mr. Phukan,

       

        If we check the psychrometric charts, we will find that 1 kg of air at 35 C, and 50% humidity carries 18 gm of water. If we succeed to cool this air to 10 C, then we will be able to condense 10 gm of out of the 18 gm. 1 kg of air at 35 C occupies a volume of 870 Liter (0.87 m3). The specific heat for air is 1.01 KJ/Kg K, which means the heat needed to be extracted from air = 1.01 X (35 - 10) = 25.25 KJ/kg.

        Let us consider the low average daily consumption per person to be 240 Lit/day = 10 Lit/hr. If 10 Lit/ 10 gm = 1000, then you need to circulate 1000 kg of air/hr, that is you need to cool 870 m3 of air by 25 C in 1 hr. Your heat load will be 25250 KJ/hr /0.5 (Efficiency) = 14 KW, and your mechanical load will be 870 m3 of air/hr = 1 KW, then your needed electrical supply is equal to 15 KWhr, which will need 90 - 100 m2 of solar panels to generate 10 lit/hr of water to cover the restricted water needs of one person????

          I do not want to comment????

  3. Sounds too good to be true? if water could be harvested in arid regions, why are those regions arid?