Artist’s rendition of Fraunhofer’s method of converting
humidity to water. Image sourced from Fraunhofer

Research scientists at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart are working in conjunction with the company Logos Innovation to develop the method of obtaining drinking water from air humidity.

The process is based on renewable solar energy sources and is completely energy autonomous, allowing it to function in regions where there is no electrical infrastructure.

The process uses a hygroscopic brine-saline solution that absorbs moisture. The solution runs down a tower-shaped unit absorbing water as it goes. It is then sucked into a tank a few meters off the ground in which a vacuum prevails.

Energy from solar collectors is brought into play on the brine in the vacuum, heating it, and diluting it of the water it has absorbed via evaporation. The evaporated, non-saline water is condensed and runs down through a completely filled tube in a controlled manner. The reconcentrated brine then runs down the tower surface again to re-absorb more moisture from the air and repeat the cycle.

Prototypes have been built for both system components – air moisture absorption and vacuum evaporation – and the research scientists have already tested their interplay on a laboratory scale. In a further step, the researchers intend to develop a demonstration facility.


-  Katrice R. Jalbuena

Sources:

¹ http://www.fraunhofer.de/EN/press/pi/2009/06/ResearchNews062009Topic2.jsp
² http://www.fraunhofer.de/EN/