Where Water Is Scarce, You Can Drink The Air!
In desert climates where the ground may be too dry for even a cactus to survive, researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) and their colleagues at Logos Innovationen have created a method for getting drinkable water from... the air!
Even in the heart of Israel's Negev Desert where there are no lakes, rivers, or ground water, there is an average daily humidity of 65 percent in the air. That translates into 11.5 milliliters of water per every cubic meter of air -- a little more than one-third of an ounce.
It doesn't sound like much, but there's a lot of air in the desert! The IGB technology uses hygroscopic brine, a saline solution that absorbs moisture from the air, which runs down a tower like structure until it is sucked into a vacuum tank a few feet off the ground. The tank, heated by solar energy and a vacuum process that enables boiling temperatures at below 100°, boils the brine, separating out the water. The brine continues its circuit of absorbing moisture from the air, while the clean water is sucked out of the tank by the gravity of a water tube. A vacuum pump is not needed to collect the water because the constant gravity of the water tube is used instead.
“The process we have developed is based exclusively on renewable energy sources such as thermal solar collectors and photovoltaic cells, which makes this method completely energy-autonomous. It will therefore function in regions where there is no electrical infrastructure,” says Siegfried Egner, head of department at the IGB.
“The concept is suitable for various sizes of installation. Single-person units and plants supplying water to entire hotels are conceivable,” says Egner.
Egner and his colleagues have tested their invention on a laboratory scale, and next, they intend to build a demonstration facility.