The arid desert landscape of Death Valley is not the obvious place to find water. Yet it’s here, in one of the planet’s hottest and driest places, that Massachusetts Institute of Technology engineers decided to test new technology to pull drinking water from an unconventional source: the air.
Their water harvesting device is a window-sized panel made with absorbent material called “hydrogel,” which has been infused with salt, folded up like origami and enclosed in glass.
The material, which looks like black bubble wrap, absorbs water vapor directly from the air, swelling up as it does so, then shrinking again as the water evaporates. The water condenses on the glass and flows down a tube to emerge as fresh, drinkable water. No power is needed, just heat from the sun.
The device doesn’t produce a huge amount of water from the bone-dry air — around two-thirds of a cup a day — but the ultimate aim is to supply a household with drinking water even in arid deserts, said Xuanhe Zhao, a mechanical engineering professor at MIT.
Water scarcity is a huge global issue. More than 2 billion people lack access to safe drinking water, a situation set to worsen due to climate change, which fuels longer and more severe drought. As reservoirs shrink, groundwater dries up and rainy seasons become more erratic, some believe one answer to this crisis lies in the reservoirs of moisture in our skies.
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