Extraction of water from the air may seem fantastic, but the technology is quite real and it could, in fact, become one of the most important innovations of the last few decades, since population growth, geopolitics, natural and anthropogenic changes in the environment contribute to a critical shortage of drinking water.

The problem is only getting worse: by 2050, 87 countries of the world will experience a shortage of drinking water. Air-to-air technology, also known as atmospheric water generator (AWG), is a technology that can efficiently condense water vapor from ambient, usually humid, air using a variety of methods.

How this is achieve is by technological processes, but most of them use the process of condensation and collection of water. There are other methods, including the use of dryers or pressure to achieve the same goal. These technologies work on the extraction of water from the air to obtain drinking water.

Illustration pixabay

Short story

Such technologies are critical in areas of the world where clean drinking water is scarce or difficult to obtain. While most AWG devices can only extract a small amount of drinking water, this is much better than no access to clean drinking water at all. However, the methods of extracting water from the air actually have a long history.

For example, the Incas collect rainwater and sent it to storage and distribution tanks using aqueducts. Another interesting historical example is a condensation well, design to collect water by condensing moisture from the air on the colder surface of the stones in the tower.

Another interesting example of water extraction from air was develop by Russian engineer Friedrich Siebold around 1900. Inspire by the mysterious piles of ancient stones near the ruin city of Feodosia, Siebold decide to test his hypothesis that these were ancient condensers of water from the air.

He found that each pile of ancient stones cover approximately 900 square meters. m. and was associate with the remains of terracotta pipes, which apparently led to wells and fountains in the ancient city. Siebold conclude that there must have been some ancient method of collecting water, and set about creating a modern example to test his hypothesis. Its construction was completed around 1912 and it was allegedly capable of producing around 360 liters of water per day, but no official reports are known.

Friedrich Siebold, photo kafanews

Modern developments

Many modern technologies in a wide variety of areas of human activity have been develop through observations of nature. Scientists, observing certain phenomena in nature, then create technologies with similar natural processes. For example, when it comes to extracting water from the air, the desert beetle Stenocara gracilipes, found in African deserts, has an effective mechanism for this seemingly impossible task.

These little bugs live in one of the driest areas on Earth – the Namib Desert, in southwestern Africa. In response to the extreme climate, these creatures have develop a strategy of extracting water from the air through an action call “fog bathing,” a behavior in which the beetle tilts its body toward the wind, allowing water droplets to condense from the fog onto its body.

Then, these drops flow down the shell of the beetle’s wing and are sent to its mouth. This strategy is incredibly effective and has pique the interest of scientists trying to find ways to provide clean water to people around the world who are experiencing water shortages. Studying the anatomy of the beetle down to the smallest detail, a team of scientists tried to reproduce the texture of its abdomen using 3D printing. They found that the fewer and more bumps, the better the surface absorbs moisture.

Scientists have found that the surface works best when condense water is quickly drained away, which, from the beetle’s point of view, is the most effective strategy for survival. If this technique can be replicate with technology and apply on an industrial scale, in theory, it could be use to create a highly efficient method of providing clean water to some water-stress countries around the world.

Stenocara gracilipes, photo by Yandex

Tsunami Products Technology

One of the interesting technologies being develop by the American company Tsunami Products is that the condensing unit works by drawing air “through a series of condensing coils”. The unit passes air and water through a series of special exhaust chambers, which have a number of functions that contribute to the further condensation of water. All liquid water is then filter for potential contaminants (such as pathogens, pollen, etc.) and then collect in a dedicate storage tank, ready for consumption or distribution.

The device works best in areas with high humidity such as fog or coastline and, depending on the size of the device, it is capable of producing between 900 and 8600 liters of water per day. Unfortunately, these devices are very expensive, ranging from $ 30,000 to $ 200,000, depending on their capacity. The device also uses a lot of power. However, when combine with a clean energy source such as solar panels, installation costs can be lower.

DARPA technology

Another interesting technique for extracting water from the air is being developed by the Defense Advanced Research Projects Agency (DARPA), which is suppose to provide 150 soldiers with clean water every day. This technology is base on small distribution systems that extract drinking water from the atmosphere for the drinking needs of soldiers and groups, even in extremely arid climates. DARPA technology is still under development.

Technology from Zurich

With the help of new technology, develop by researchers from the Swiss Higher Technical School of Zurich, it was possible to develop a water generator from the air, which can work autonomously at any time of the day. This technology uses a combination of special polymer and silver layers to give the glass special properties that cause water to condense out of the air.

Installation from Zurich, photo 

The coatings are apply to glass, which is house in a special taper radiation shield that passively allows the glass to cool as much as 15 degrees Celsius below ambient temperature for any given region. This creates a temperature difference, which in turn causes condensation of water from the air, where moisture is trap under the cone.

To help with collecting water, the team also develop a special water-repellent coating on the underside of the glass that quickly promotes the formation of water balls, which can then drain and collect. According to the researchers, the whole process is energy-free and works great even during the day thanks to the radiation shield. Experimental studies have shown that the device can collect up to 53 ml of water per tenth of a square meter of glass surface per hour, under ideal conditions. Not bad.

Technology from Texas

Another interesting water-from-air generator was develop by researchers at the University of Texas at Austin. Base on the so-call “super sponge” principle, this machine uses solar energy to produce drinking water from the air. The device of the machine is a special hybrid hydrogel and gel-polymer material that holds liquid water very well.

Using this material, the machine can extract drinking water from the air. When the water needs to be drain from the gel, all you have to do is heat it up. “ We have develop a completely self-contain system in which all you have to do is leave the hydrogel outside and it will collect water ,” said Fei Zhao, research scientist and co-author of the study. “The collect water will remain in the hydrogel until you expose it to sunlight. After about five minutes in natural sunlight, the water will be release . ”

Illustration pixabay

Current design trials have produce about 50 liters of hydrogel per kilogram, which should be more than enough for most household applications. If commercially produced, this technology could be a game changer for many water-stress regions of the world, especially when combined with solar power. It can also be use to improve existing water harvesting methods, making them efficient and less energy intensive.

US Department of Energy Technology

Several years ago, the US Department of Energy’s Pacific Northwest National Laboratories (PNNL) introduce a new method for extracting water from the air. This new method, discover entirely by accident, uses carbon-based nanorods to adsorb water at low humidity. The rods also spontaneously remove about half of any trap water when the relative humidity exceeds 50-80%. The displacement of water is completely reversible and is explain by interfacial forces between the limit surfaces of the rod.

Surprisingly, the discovery came entirely by accident when chemist Satish Nune was studying nanorods with a vapor analyzer. He was surprised to find that the rods seemed to work contrary to other water receptors, as the rod assembly actually lost mass as external moisture increase. This was an obvious surprise, but closer examination reveal that this strange behavior was due to the variable distance between the rods.

When the humidity is low, the rods can maintain a relatively large distance between them, which allows water to adhere to them. However, as the humidity rises, the capillary action of the water brings the rods closer together, which, in turn, squeeze out and displace the water adher to the rod. Interestingly, a similar process was suppose back in the 1990s, but so far nothing has come of it. It is now hope that this strange can somehow be use on a large phenomenon scale to harvest water in arid desert regions.

Nanorods illustration PNNL

WEDEW technology

The technology develop by the American company WEDEW won the $ 1.75 million award in 2018 for the most realistic solution to the growing global water crisis. Their technology is capable of producing at least 2,000 liters of water from the atmosphere every day, all from organic waste. XPRIZE is sponsor by Indian TATA Group and Australian Aid Group.

House inside the shipping container, a condensation device for water from air is capable of creating and maintaining a humid environment inside the container, as well as generating clean drinking water using the Skywater device. The device not only produces drinking water, but also produces nutrient-rich waste such as charcoal, which can be use as a natural fertilizer for crops.

Fontes Aero technology

Another interesting AWG is a self-filling water bottle call Fontes Aero. Ideal for outdoor enthusiasts, these bottles fill up in less than an hour. The bottles were design by Austrian engineer Christoph Retesar. Unlike other solutions on this list, bottle technology is relatively simple and portable.

The bottle works by allowing moist air to enter the device, causing the air to be expose to so-call hydrophobic “teeth.” Resembling the bristles of a toothbrush, these “teeth” cause water vapor to condense from the air to form water droplets ready to be collect.

Fontus Airo bottle, photo by Fontus

The device is power by a rechargeable solar panel built into the bottle. According to the creator, the bottle is most effective at temperatures ranging from 30 degrees Celsius to 50 degrees Celsius and 80 to 90% humidity.

Fontus can produce approximately 0.5 liters of water per hour. Since its inception, the product has been release to the market for both cyclists and travelers. There are other technologies, but there is no point in considering them.

However, it should be note that the technology of extracting water from the air is a very real and very promising area of ​​technology that can provide clean water to many countries of the world. If warnings of an impending water crisis are warrant, technologies such as those describe above could prove critical to the survival of many millions of people around the world.