This device may pull water out of thin air, but not as well as we hoped

The March/April 2017 issue of Popular Science was all about water. We covered the gamut, from how much of this essential liquid goes into the foods you eat, to what happens when you don't get enough of it, and how, in some areas, water is running out. That's why we were drawn to a simple and inexpensive invention called WaterSeer, which aims to pull moisture from the air without using any electricity, to provide clean drinking water to those in need.



Unfortunately, it's not likely that WaterSeer could pull 11 to 14 gallons of water out of the air per day, as its makers claim. And there are a few other problems with it as well.

It won't work in arid regions
WaterSeer is supposed to work by blowing air into an underground chamber. During the daytime, ground temperatures are lower than in the air, and because cool air can hold less water than warm air, the idea is that water vapor will condense on the cool sides of the chamber, clean and ready for drinking.

Vici Labs, the makers of WaterSeer, estimate that the device can harvest 11 gallons of water a day from semi-arid air. But the problem is that the drier the air is, the lower its dew point—the temperature needed to condense water out of it.

"In most of the areas that are being underserved by water resources, the dew points are very, very low," says thermodynamicist Kenneth Kroenlein. Ground temperatures two meters below the surface (the depth currently proposed for WaterSeer) aren't likely to stay low enough to make that condensation happen.

"It's very unlikely that you're going to be able to use condensation to pull water out of the air in dry places," says Kroenlein.

However, the device may have some success in humid areas. And although it may seem counterintuitive, water scarcity strikes even in places with lots of moisture in the air.

As opposed to physical water scarcity, which occurs in dry regions, economic scarcity can occur in regions where water may be abundant but infrastructure to deliver clean water is lacking. In Mozambique, for example, millions of people don't have access to clean drinking water. Many families—particularly women and children—have to walk for an hour or more to collect water, and unsafe water kills about 55 of the country's children a day.


Read more at: https://www.popsci.com/this-device-may-pull-water-out-thin-air-but-not-as-well-as-we-hoped#page-2

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