Shades of Frank Herbert’s water traps from Dune. Scientists say they have found a way to draw water from humid air based entirely on thermal solar collectors and photovoltaic cells that makes the method completely sustainable. Ideal environments could be deserts and undeveloped or disaster areas without electricity.
Basically, it’s a recirculating still.
Researchers from the Fraunhofer Institute describe the process using a brine saline solution that absorbs moisture, runs down a tower-shaped unit as it absorbs water from the air. The enriched brine is sucked into a vacuum tank a few meters off the ground. 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. This effect is known from the mountains: as the atmospheric pressure there is lower than in the valley, water boils at temperatures distinctly below 100 degrees Celsius. The evaporated, non-saline water is condensed and runs down through a completely filled tube in a controlled manner. The gravity of this water column continuously produces the vacuum and so a vacuum pump is not needed. The reconcentrated brine runs down the tower surface again to absorb moisture from the air.”