Drinking air.

It’s practically like the moisture farms in Star Wars. Scientific Blogging has this thing about how we could be getting drinking water from *humidity* and solar power:

“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 principle of the process is as follows: hygroscopic brine – saline solution which absorbs moisture – runs down a tower-shaped unit and absorbs water from the air. It is then sucked into a tank a few meters off the ground in which a vacuum prevails. Energy from solar collectors heats up the brine, which is diluted by the water it has absorbed. Because of the vacuum, the boiling point of the liquid is lower than it would be under normal atmospheric pressure.

Sun boils water, pure water distilled out, concentrated brine then pumped back to the top of the tower and the whole thing starts again.