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2019-06-28. New solar technology could produce clean drinking water for millions in need.

posted Jun 30, 2019, 9:00 PM by Alan Gould
By Robert F. Service, Science Magazine. [https://www.sciencemag.org/news/2019/06/new-solar-technology-could-produce-clean-drinking-water-millions-need] For GSS Energy Use chapter 10. Excerpt: ...researchers have developed a new material that speeds the process of evaporation, enabling a small solar still to provide all the drinking water one family needs. If the technology proves cheap enough, it could provide millions of impoverished people access to clean drinking water. Today 783 million, or nearly one in 10, people around the world lack such access, according to UNICEF. These people spend a collective 200 million hours a day fetching water from distant sources. ...The traditional still is little more than a black-bottomed vessel filled with water and topped with clear glass or plastic. The black bottom absorbs sunlight, heating water so that it evaporates and leaves the contaminants behind. The water vapor then condenses on the clear covering and trickles into a collector. ...Operating at their theoretical best, such devices can only produce 1.6 L/h/m2. ...Guihua Yu, a materials scientist at the University of Texas in Austin, and colleagues recently reported a way around this limit. It involves hydrogels, polymer mixtures that form a 3D porous, water—absorbent network. ...Using this technology, Yu’s solar still produced 3.2 L/h/m2 of water, double the theoretical limit, his team reported last year in Nature Nanotechnology....