This water harvesting device has been field-tested in the Mohave Desert. The harvester produced seven-tenths of a liter per kilogram of absorber per day; that's about three cups of water. The harvester can run twenty-four hours per day, powered by solar panels and a battery.
Water Harvesting Inc., is now testing and will soon market a device the size of a microwave oven that can supply 7 to 10 liters of water per day: enough drinking and cooking water for two to three adults per day, based on recommendations from the National Academy of Sciences that men should consume 3.7 liters and women 2.7 liters of fluid per day.
An even larger version of the harvester, one the size of a small refrigerator, will provide 200 to 250 liters of water per day, enough for a household to drink, cook and shower. And in a couple of years, the company hopes to have a village-scale harvester that will produce 20,000 liters per day. All would run on power from solar panels and a battery or off the electrical grid.
The harvesterís secret ingredient is a type of MOF [metal-organic framework] invented by Yaghi and his UC Berkeley colleagues that easily and quickly takes up water from the air and just as readily disgorges it so the water can be collected. MOFs, which Yaghi has been developing since the mid-1990s, are so porous that a gram has a surface area equivalent a football field.
Fans of Star Wars of course recall the vaporators essential to farming the deserts of Tatooine:
For human purposes, however, the water of Tatooine was only marginally accessible. The atmosphere yielded its moisture with reluctance. It had to be coaxed down out of the hard blue sky -- coaxed, forced, yanked down to the parched surface.
Two figures whose concern was obtaining that moisture were standing on the slight rise of one of those inhospitable flats. One of the pair was stiff and metallic -- a sand pitted vaporator sunk securely through sand and into deeper rock. The figure next to it was a good deal more animated, though no less sun weathered.
Scroll down for more stories in the same category. (Story submitted 9/5/2019)