Water-harvesting device to gather 10 gallons of water an hour from air

Women
carry jerry cans of water from shallow wells dug from the sand
along the Shabelle River bed, which is dry due to drought in
Somalia’s Shabelle region.
Thomson
Reuters

• A team of researchers at the University of Akron is
  developing a device that can harvest
  drinking water from thin air.
• The device uses nanoscale polymers to capture
  condensation and it could be battery-powered, according to the
  researchers.
• The team is now looking for funding to develop a
  working prototype of the
  water harvester. 
• “Every human should be entitled to fresh water,” Dr.
  Josh Wong, the lead researcher on the project
  said. 

---

A team of scientists at the University of Akron in Ohio is
working to solve one of the most pressing issues humanity

will face in the future: access to fresh, clean drinking
water.

To do that, the team is developing a prototype water harvester
that can essentially produce up to 10 gallons per hour of
drinking water from thin air. 

“Every human should be entitled to fresh water,” Dr. Josh Wong, a
professor of mechanical engineering at the University of Akron,
told Business Insider. “Not just the 0.1%”

That notion spurred Wong — an expert in polymers — to work on a
water harvester prototype that can be cheaply and effectively
used in regions where water is scarce.

A
mockup of the water harvester, which could be a wearable
backpack.
Courtesy of Dr. Josh Wong/
University of Akron

The amount of water vapor present in the atmosphere is referred
to as humidity. In tropical regions with high relative humidity
— the percentage of water vapor in the air as a
function of the temperature — it’s pretty easy to use devices
called fog catchers to turn that water vapor into drinkable
water.

But in drier places like
California or the Andes, fog catchers are rendered
“ineffective,” according to Wong. And, though countries like
Israel have been experimenting with desalination, Wong said the
process is too expensive to be deployed at scale, particularly as
water shortages become more acute in poorer regions as the world
warms as a result of
climate change. 

To develop a water harvester, the team took inspiration from both
biology and history.

“The atmosphere is one of the most abundant sources of water we
have. Just look at your local weather forecast or the hurricane

bearing down on Hawaii,” Wong said. “We haven’t fully
explored it.”

Wong pointed out that indigenous communities in the Andes
mountains — high altitude deserts where it rains infrequently —
have used techniques to capture atmospheric water for centuries.
Historically, these communities would collect dew inside pits
located in the desert. In the morning, they’d collect the dew and
channel it into large cisterns, providing them with fresh
drinking water. 

The Namib Desert Beetle also served as an inspiration. These
beetles, which live in some of the driest deserts on Earth, have
bodies that are adapted for water collection. To drink, they
simply climb up to the highest point — say, a sand dune — and
point their abdomens towards the wind.

The wind, which blows off the ocean and carries water particles,
condenses on their bodies. They have special grooves to channel
the condensation into their mouths. 

Wong and his team set out to “miniaturize,” the process of
harvesting atmospheric water using electrospun polymers. 

Electrospinning can produce polymers as small as a few tens of
nanometers across, which means that a huge surface area can be
packed into a really small space. That makes the
nanoscale-polymers super-efficient at collecting water, even in
arid environments. The device, which could be powered by a
lithium-ion battery, would also be able to filter water because
the surface of the material would slough off any microbes or
bacteria present in the water vapor. 

While that may seem complicated, Wong said it’s not much
different than how people in the Andes, and Namib beetles collect
water — it’s just at a much smaller scale.

To illustrate the example, Wong said it’s similar to wearing
eyeglasses in the summer heat. When you step into an
air-conditioned room from outside on a hot, humid summer day,
your glasses will likely fog up. That fog can be collected at a
nano-scale.

While other researchers have worked on
developing water harvesters, Wong said his concept would be
smaller and cheaper, and therefore the easiest to scale than
other research-stage water harvester prototypes. It could take
the form of a backpack, or even be placed onto a rolling train
where the water could be collected and delivered to communities.

He presented his findings at a meeting of the
American Chemical Society earlier this week, and his
team is seeking funding to develop a working prototype for the
project.

“Many people will suffer from water shortages around the world in
the coming years,” Wong said. “We’re hoping we can address this
problem.”