A Window-Sized Water Harvester That Works Everywhere
A Window-Sized Water Harvester That Works Everywhere
A device built by MIT researchers extracts water from the air in Death Valley, California, using solar power and biomaterials.
Access to clean, safe drinking water remains a pressing issue for billions of people worldwide. According to global estimates, approximately 2.2 billion individuals live without reliable access to safe water.
Even in the United States, a country with vast infrastructure, over 46 million people face water insecurity—either lacking indoor plumbing altogether or relying on water sources that are unsafe for consumption. Climate change, population growth, and pollution continue to strain existing water systems, and traditional sources like lakes, rivers, and reservoirs are no longer sufficient to meet growing demands.
In response to widespread water insecurity, engineers at the Massachusetts Institute of Technology (MIT) are exploring an unconventional yet abundant source of water: the air around us.
The atmosphere contains an immense quantity of water in the form of vapor—estimated to be several billion gallons globally. Though invisible, this vapor presents a significant opportunity. If captured and condensed efficiently, it could offer a new, decentralized supply of drinking water, especially in regions with limited access to surface or groundwater sources.
With this resource in mind, the team developed a water harvester using specific substances to successfully remove water from air that is suitable to drink.
The technology behind the prototype equipment focuses on a hydrogel-based water harvester that overcomes a common issue in similar systems: salt contamination. Hydrogel is a water-attracting polymer that can absorb and retain large amounts of water—sometimes up to hundreds of times its dry weight—without dissolving.
Traditional hydrogels often incorporate salts such as lithium chloride to enhance water absorption. However, these salts are capable of leaching out during collection, resulting in water that requires additional purification.
An up-close look at the hydrogel material that swells to absorb water from the air. Image: Zhao Lab
The team added glycerol, a colorless and water-soluble compound, to the hydrogel formula, stabilizing the salt and preventing crystallization or leakage during water collection. The gel’s microstructure also eliminates nanoscale pores, reducing further salt release.
As a result of the glycerol and hydrogel combination, the collected water had salt levels well below drinking water safety standards and significantly lower than those found in earlier hydrogel designs.
Beyond composition, the team redesigned the gel’s shape to boost efficiency. Rather than a flat sheet, they molded the gel into a pattern of small domes, such as bubble wrap, which increased surface area and enhanced the material’s ability to absorb water vapor from the air.
To harness this potential, an MIT research team has designed an innovative device capable of extracting moisture from the air. Known as an atmospheric water harvester, this system captures water vapor and converts it into liquid water using energy-efficient techniques. The team’s testing has shown that the device can operate effectively across a broad range of humidity levels—including in arid, desert-like conditions where conventional methods fail.
Researchers (from left to right), Shucong Li, “Will” Chang Liu, and Xiao-Yun Yan, with two atmospheric water harvesters. Image: Zhao Lab
Xuanhe Zhao is the Uncas and Helen Whitaker Professor of Mechanical Engineering at MIT, and leads the interdisciplinary research group behind the atmospheric water harvester at Zhao Lab.
Zhao states the researchers were challenged to achieve a low-cost, scalable, easy-to-use, and easy-to-maintain system, where major applications are available for resource-limited, off-grid regions.
“Our lab is studying soft materials, including hydrogels,” explains Zhao. “We understand that certain hydrogels containing salts can absorb a substantial amount of water from air. Therefore, we decided to harness the hydrogel systems to address the water harvesting challenge.”
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The technology represents a promising step forward in the effort to secure sustainable and accessible water supplies. By tapping into atmospheric moisture, MIT’s approach offers a scalable solution for communities facing water scarcity, potentially transforming how drinking water is sourced in the face of environmental and infrastructural challenges.
The current design is an early-stage prototype with significant room for improvement. Future enhancements may include using multiple panels and developing a more advanced version of the material to boost its performance.
Xuanhe Zhao, Professor of Mechanical Engineering at MIT. Image: Zhao Lab
Zhao added that the water harvester they developed is usable in areas with limited resources—places where even solar panels are hard to come by. He noted that this marks an important step in proving the technology could be scaled up. The hope is that others can expand on the design, either by enlarging the system or creating multiple units, to help provide clean drinking water and make a meaningful difference in people's lives.
Looking ahead, the vision involves deploying compact, vertically oriented arrays that take up minimal space. These could be installed in groups to continuously harvest water, potentially serving individual households in areas with limited access to clean water. Further field testing in underserved regions is already being planned.
Jim Romeo is a technology writer in Chesapeake, Va.
Even in the United States, a country with vast infrastructure, over 46 million people face water insecurity—either lacking indoor plumbing altogether or relying on water sources that are unsafe for consumption. Climate change, population growth, and pollution continue to strain existing water systems, and traditional sources like lakes, rivers, and reservoirs are no longer sufficient to meet growing demands.
Solutions for sustainable water
In response to widespread water insecurity, engineers at the Massachusetts Institute of Technology (MIT) are exploring an unconventional yet abundant source of water: the air around us.
The atmosphere contains an immense quantity of water in the form of vapor—estimated to be several billion gallons globally. Though invisible, this vapor presents a significant opportunity. If captured and condensed efficiently, it could offer a new, decentralized supply of drinking water, especially in regions with limited access to surface or groundwater sources.
With this resource in mind, the team developed a water harvester using specific substances to successfully remove water from air that is suitable to drink.
Harvesting water in the desert—how does it work?
The technology behind the prototype equipment focuses on a hydrogel-based water harvester that overcomes a common issue in similar systems: salt contamination. Hydrogel is a water-attracting polymer that can absorb and retain large amounts of water—sometimes up to hundreds of times its dry weight—without dissolving.
Traditional hydrogels often incorporate salts such as lithium chloride to enhance water absorption. However, these salts are capable of leaching out during collection, resulting in water that requires additional purification.
An up-close look at the hydrogel material that swells to absorb water from the air. Image: Zhao Lab
As a result of the glycerol and hydrogel combination, the collected water had salt levels well below drinking water safety standards and significantly lower than those found in earlier hydrogel designs.
Beyond composition, the team redesigned the gel’s shape to boost efficiency. Rather than a flat sheet, they molded the gel into a pattern of small domes, such as bubble wrap, which increased surface area and enhanced the material’s ability to absorb water vapor from the air.
A low-cost, scalable system
To harness this potential, an MIT research team has designed an innovative device capable of extracting moisture from the air. Known as an atmospheric water harvester, this system captures water vapor and converts it into liquid water using energy-efficient techniques. The team’s testing has shown that the device can operate effectively across a broad range of humidity levels—including in arid, desert-like conditions where conventional methods fail.
Researchers (from left to right), Shucong Li, “Will” Chang Liu, and Xiao-Yun Yan, with two atmospheric water harvesters. Image: Zhao Lab
Zhao states the researchers were challenged to achieve a low-cost, scalable, easy-to-use, and easy-to-maintain system, where major applications are available for resource-limited, off-grid regions.
“Our lab is studying soft materials, including hydrogels,” explains Zhao. “We understand that certain hydrogels containing salts can absorb a substantial amount of water from air. Therefore, we decided to harness the hydrogel systems to address the water harvesting challenge.”
Discover the Benefits of ASME Membership
The technology represents a promising step forward in the effort to secure sustainable and accessible water supplies. By tapping into atmospheric moisture, MIT’s approach offers a scalable solution for communities facing water scarcity, potentially transforming how drinking water is sourced in the face of environmental and infrastructural challenges.
Work in progress
The current design is an early-stage prototype with significant room for improvement. Future enhancements may include using multiple panels and developing a more advanced version of the material to boost its performance.
Xuanhe Zhao, Professor of Mechanical Engineering at MIT. Image: Zhao Lab
Looking ahead, the vision involves deploying compact, vertically oriented arrays that take up minimal space. These could be installed in groups to continuously harvest water, potentially serving individual households in areas with limited access to clean water. Further field testing in underserved regions is already being planned.
Jim Romeo is a technology writer in Chesapeake, Va.
A device built by MIT researchers extracts water from the air in Death Valley, California, using solar power and biomaterials.
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