UT Austin
A prototype developed by the University of Texas transforms ordinary fabric into a portable moisture capture system, capable of producing up to 900 milliliters of drinking water per day in external tests.
Most devices capable of extracting water from the air have one characteristic in common: stands still. A new water-harvesting jacket breaks this logic, by remove moisture from the air while the person walks.
The usual water collection system is a box on a roofa panel in a backyard or a damp container in a corner — equipment that is installed and works in the same place. This one has no box or panel. Just dress him up.
The fabric captures moisture from the air as the wearer moves, in a type of water collection that, until now, required a stand-alone machine.
Behind the innovation, which was presented in a recently published in the magazine Science Advancesare engineers from the University of Texas at Austin (UT Austin), led by professor Guihua Yuwho has been working on this problem for several years.
The usual water collection approach keeps the material sitting in one place. Yu’s team wanted the opposite: a water fountain that moved with you.
But, as they would say there next to Austin, in Houston: “we have a problem“: small samples can capture water very effectively. But when they are scaled up to the scale of a real deviceperformance drops abruptly.
Volume is the enemy. A large block of the material captures a lot of vapor on the outer surface, but then has difficulty transporting this water to the interior. Doubling the size never doubles the capture.
Other teams of researchers have sought to achieve this goal through different routes, including a recent one that integrated fibers capable of capturing moisture in fabric. But taking these gains to a truly usable scale has been a recurring obstacle.
The group of Yu concentrated in the fiber itself. Ordinary spun fibers form a kind of outer layer sealed around a tight core, which slows down both the capture of vapor and its passage to the interior.
The new design opens this outer layer and creates branching channels inside, to draw water faster. And it worked: In tests, the best fibers absorbed more than their own weight in water in about 20 minutes.
The basis of the system is a hydrogela soft gel that absorbs water. It is made from material of plant origin and combined with lithium chloride, a salt that removes moisture from the air.
UT Austin
Speed was the real advancementsays the team: water passed through the fabric faster than was possible in previous designs.
The design maintained performance in larger dimensionsprecisely the point where previous materials had failed. A sample measuring about 20 centimeters on a side retained 3/4 of the capture capacity of a sample the size of a fingernail — a performance three to ten times higherr to that of previous materials on this scale, and was obtained with conventional equipment.
The coat has four collection units — two larger and two smaller panels, distributed across the front and back.
When a unit has absorbed the maximum amount of moisture, it is removed and placed in a collapsible collector. A small heater forces the trapped water to come out again in the form of steam. This vapor cools, turns into liquid and flows into a channel, where it accumulates as drinking water.
The cycle works on a simple rhythm of absorption and heating. No fixed plumbing.
Lab numbers are one thing. The real conditions are different. The researchers tested the coat abroadin Austin and two locations in China, including a dry and remote areafar from any tap.
In these locations, the coat produced between 400 and 900 milliliters of water drinkable per day, depending on humidity. That is, one to two bottles, obtained only from air.
The water came out clear. It contained only trace amounts of lithium and met World Health Organization standards for drinking water—the kind of water that could be collected and drunk at the moment.
Clothing is just the beginning. The same fabric can be integrated into backpacks, tents and emergency shelters, transforming common equipment into a discreet form of reinforce water supply.
This result in the desert suggests where this technology could be most useful. It should work better in many of the driest regions and with the highest water pressure in the world, where it is difficult to build pipes and reservoirs.
What the jacket demonstrates is simple: a material capable of trapping moisture can be woven into a breathable, wearable garment while maintaining the ability to produce drinking water on the scale of an actual garment.
