Device harvests water from air to end droughts

‘If you were cut off somewhere in the desert you could survive with this’

DROUGHTS could be consigned to history by a water harvester which can pull moisture out of the air using only the power of the sun.

The prototype designed by scientists at MIT and the University of California works even in desert conditions. The device could eventually provide households with all the drinkable water they need, by extracting dampness from the surrounding atmosphere.

The solar-powered harvester can provide 2.8 litres of water from the air over a 12-hour period in conditions as dry as the Mojave Desert, where the average humidity is around 20 per cent.

“This is a major breakthrough in the long-standing challenge of harvesting water from the air at low humidity,” said Prof Omar Yaghi, at UC Berkeley.

“One vision for the future is to have water off-grid, where you have a device at home running on ambient solar for delivering water that satisfies the needs of a household.”

The device is an open-air chamber containing a lattice-like structure made from zirconium metal and adipic acid sandwiched between a solar absorption panel and a condenser plate.

The zirconium and acid structure traps the water vapour then sunlight drives it towards the cooler condensing plate which returns the vapour to liquid so it can drip into a collector.

Two-thirds of the world’s population experience water shortages yet there is an estimated 13,000 trillion litres in the atmosphere.

The team is planning to improve the harvester so it can suck in much more air, and produce more water, but even the prototype is powerful enough to keep someone alive in a desert.

“We wanted to demonstrate that if you are cut off somewhere in the desert, you could survive because of this device,” said Prof Yaghi.

“A person needs about a Coke can of water per day. That is something one could collect in less than an hour with this system.”

The research was lished in the journal Science.