Adithi Ramakrishnan | (TNS) The Dallas Morning News
In Star Wars, Luke Skywalker grows up on the hot desert planet of Tatooine. His family owns a moisture farm that uses so-called “vaporizers” to pull drinking water out of the air.
But while vaporizers are a sci-fi pipe dream, the technology that makes them work may be getting closer to reality.
Researchers from Xianming “Simon” Dai’s lab at the University of Texas at Dallas are developing technology that can pull water out of the air. They recently published an article in the journal Proceedings of the National Academy of Sciences presenting a more efficient method of water harvesting inspired by a carnivorous plant.
The technology still has a long way to go before it is ready for human use. However, researchers hope to one day develop a wearable device that would give people access to clean water when water is scarce.
“We try to get water anywhere, anytime, anywhere. That’s our goal,” said Dai, a UTD assistant professor of mechanical engineering.
combat water scarcityAccording to the US Drought Monitor, a partnership between the National Drought Mitigation Center, the US Department of Agriculture and the National Oceanic and Atmospheric Administration, 62% of Texas faced extreme drought in August.
Triple-digit temperatures, like those experienced by Dallas this summer, can exacerbate heat waves and droughts, and lead to water shortages.
Dai is interested in decentralized water distribution: getting people the water they need without the use of city-regulated water treatment plants and reservoirs. He has been involved in water harvesting for the past 10 years in hopes of improving access to clean water by harnessing a natural process called condensation.
When you take a cold glass of water outside on a hot day, tiny droplets of water can form on the rim of the glass. The warm water vapor in the air is attracted to the cold glass and cools or condenses into these droplets.
Dai and his lab wanted to use a similar approach to obtain water. If they could keep a surface cool and attract warm water vapor, they could condense the water into droplets and trap it.
nature as inspirationOne problem slowing current water harvesting technology is that once water droplets form on a surface, they have nowhere to go.
They accumulate on the surface and slow down the formation of new droplets. Dai and his lab developed a novel solution to this problem that collects water droplets much like the carnivorous pitcher plant devours insects.
The vase-shaped pitcher plant attracts its prey by secreting sweet nectar. When an insect lands on the slippery top edge of the plant, it falls into the “vase” where it is digested.
Dai and his lab created a similar “trap” for already formed water droplets by creating multiple T-shaped channels – smaller than a human hair in diameter – in their test water collection system, a rectangle of silicon about 2 centimeters wide.
During water absorption, the water droplets form at the very top of the T, which is coated with a slippery lubricant. Then the droplets slide from the T into channels where they are collected.
“If you can remove the droplet from the surface, you have more surface area for recondensation,” said Dylan Boylan, a Ph.D. in the second year. Student in Dai’s lab.
The laboratory’s water collection technique increased the water collection rate compared to a model without the T-shaped channels. According to Boylan, in humid conditions, their quilt could fill a glass of water in about seven minutes.
Put it on the scalesDai’s use of canals to obtain water more efficiently has not been thoroughly explored in existing research. There is still work to be done before its technology is commercially available.
Dai’s water harvesting system relies on keeping its surface cold to draw in warm water vapor for condensation. That takes energy — primarily to produce enough water to keep a family hydrated during a shortage. The technology also relies on steam being present in the air to create water from it, meaning it could be more difficult to work in hotter, drier climates.
Sameer Rao, an assistant professor at the University of Utah whose research interests include water harvesting and purification, said Dai’s research is an exciting advance in the field. He added that future research will be needed to see if this technology can be scaled up to address a problem as big as nationwide or global water scarcity.
“It’s promising,” said Rao, who was not involved in Dai’s study. “But I think questions like, ‘Is that promising if you make a million of these?’ is something worth exploring.”
Now that Dai’s lab has the basics of the technology, his team is working to figure out how to package it into something that’s scalable and affordable. Dai also sees applications for his work in systems like air conditioning, where extracting vapor from the air could help control a room’s humidity.
He said one of his favorite parts of researching water harvesting is using nature’s mysteries to improve human life. Nature has been collecting water for some time: the Namib desert beetle, native to southwest Africa, stays hydrated by having drops of water condense on its back, which drip into its mouth.
Dai and Boylan hope that one day people will benefit from this process. “When we see that nature can do that, we can take that idea and make it happen for ourselves,” Boylan said.
https://www.ocregister.com/2022/11/28/star-wars-to-science-researchers-harvest-water-from-air-to-address-shortages/ Researchers Harvest Water from Air to Fix Bottlenecks – Orange County Register