Researchers from MIT and University of California Berkeley have been able to find water in the most unlikely spot: the desert air. It may seem like this is almost impossible, deserts are known for being the driest areas on Earth after all. But all air, even desert air, has some percentage of moisture in it. The research team has developed a system that can extract the moisture from dry desert air, which could be incredibly helpful for people living in desert areas where water is hard to find.
This extractor was proposed in 2016, but researchers have successfully field-tested the device in Tempe, Arizona. The air in Tempe is famously dry, so extracting water from this air was a feat. The success of the initial testing of the extractor proves that the new method can work, even though there is still a lot of work to be done.
There was a paper published last year on this research, which gathered a lot of attention, according to Evelyn Wang, Gail E. Kendall Professor in the Department of Mechanical Engineering and senior author of last year and this year’s paper.
"It got a lot of hype, and some criticism," said Wang, "All of the questions that were raised from last time were explicitly demonstrated in this paper. We've validated those points."
The extractor is made out of high surface materials called metal-organic frameworks (MOFs). MOFs can extract water from the air, even in the air where the humidity is as low as 10 percent. There are some extractors that can pull water from the air, but they require high humidity of 50 percent or more in fog and dew harvesting refrigeration systems. The goal for the new system is to fill a need for water in the driest areas of the world.
In order to test the extractor, a test device was put on the roof of Arizona State University in Tempe. The system was successful, producing a few millimeters of water.
“The team was field-testing in a place that's representative of these arid areas, and showed that we can actually harvest the water, even in subzero dewpoints," said Wang.
The test device was powered only by the sun. The researcher hopes that if the device is scaled up it could remain solar powered. They say that the output of a scaled-up device would potentially be equivalent to over a quarter-liter of water per kilogram of MOF. The output could be as high as three times of the current version.
The systems that require higher humidity also have pumps and compressors that can wear out easily over time. The newest system has no moving parts, therefore no wear and tear. It can run passively in areas with large amounts of sunlight.
The next steps for the researchers are to see if this system will work if it is scaled up and to attempt to boost the efficiency of the system. They want the system to be able to gather liters of water at a time.
The paper on this research was published in Science.