The Earth’s atmosphere contains enormous amounts of water. Being able to efficiently and economically extract some of it to provide drinking water would be extremely beneficial to the billions of people across the globe who face chronic water shortages.
There are existing technologies for atmospheric water harvesting – or AWH. But there are downsides associated with size, cost, and efficiency. A new device developed by mechanical engineering researchers at the University of Utah has the potential to provide a new drinking water source in arid places.
The device is a compact, rapid-cycling, fuel-fired AWH device. It relies on adsorbent materials that draw water molecules out of non-humid air and then applies heat to release those molecules into liquid form.
Hygroscopic materials are those that have an affinity for water and soak it up at every opportunity. Such materials are used, for example, in disposable diapers. The Utah device makes use of metal organic frameworks, which have enormous amounts of surface area on the molecular scale.
The initial work on the Utah device targeted a small compact water generation unit for soldiers in the field. Instead of lugging around a large canteen filled with water, the small unit can produce water on demand. The prototype was able to produce 5 liters of water per day per kilogram of adsorbent material. Within three days in the field, the system outperforms packing water. The heat required to precipitate the liquid water was provided by a standard-issue Army camping stove.
Non-military needs are the ultimate application for the device. The researchers have applied for a patent for what they hope will be a potential solution to a persistent global problem.
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Producing water out of thin air
Photo, posted August 9, 2012, courtesy of Enid Martindale via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
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