Device pulls water from dry air, powered only by the sun

April 13, 2017, University of California - Berkeley
Water harvester built at MIT with MOFs from UC Berkeley. Using only sunlight, the harvester can pull liters of water from low-humidity air over a 12-hour period. Credit: MIT / laboratory of Evelyn Wang.

Imagine a future in which every home has an appliance that pulls all the water the household needs out of the air, even in dry or desert climates, using only the power of the sun.

That future may be around the corner, with the demonstration this week of a harvester that uses only ambient sunlight to pull liters of water out of the air each day in conditions as low as 20 percent humidity, a level common in arid areas.

The solar-powered harvester, reported in the journal Science, was constructed at the Massachusetts Institute of Technology using a special material - a metal-organic framework, or MOF - produced at the University of California, Berkeley.

"This is a major breakthrough in the long-standing challenge of harvesting water from the air at low humidity," said Omar Yaghi, one of two senior authors of the paper, who holds the James and Neeltje Tretter chair in chemistry at UC Berkeley and is a faculty scientist at Lawrence Berkeley National Laboratory. "There is no other way to do that right now, except by using extra energy. Your electric dehumidifier at home 'produces' very expensive water."

The prototype, under conditions of 20-30 percent humidity, was able to pull 2.8 liters (3 quarts) of water from the air over a 12-hour period, using one kilogram (2.2 pounds) of MOF. Rooftop tests at MIT confirmed that the device works in real-world conditions.

Omar Yaghi explains how to make a MOF and their tremendous ability to absorb gases and liquids, including water directly from low-humidity air. A MOF he synthesized was used by MIT engineers to construct a water harvester that sucks water from dry air and condenses it for drinking. Video by Roxanne Makasdjian and Stephen McNally, UC Berkeley. Harvester photos courtesy of MIT.

"One vision for the future is to have water off-grid, where you have a device at home running on ambient solar for delivering water that satisfies the needs of a household," said Yaghi, who is the founding director of the Berkeley Global Science Institute, a co-director of the Kavli Energy NanoSciences Institute and the California Research Alliance by BASF. "To me, that will be made possible because of this experiment. I call it personalized water."

Yaghi invented metal-organic frameworks more than 20 years ago, combining metals like magnesium or aluminum with organic molecules in a tinker-toy arrangement to create rigid, porous structures ideal for storing gases and liquids. Since then, more than 20,000 different MOFs have been created by researchers worldwide. Some hold chemicals such as hydrogen or methane: the chemical company BASF is testing one of Yaghi's MOFs in natural gas-fueled trucks, since MOF-filled tanks hold three times the methane that can be pumped under pressure into an empty tank.

Other MOFs are able to capture carbon dioxide from flue gases, catalyze the reaction of adsorbed chemicals or separate petrochemicals in processing plants.

In 2014, Yaghi and his UC Berkeley team synthesized a MOF - a combination of zirconium metal and adipic acid - that binds water vapor, and he suggested to Evelyn Wang, a mechanical engineer at MIT, that they join forces to turn the MOF into a water-collecting system.

A schematic of a metal-organic framework. The lines in the models are organic linkers, and the intersections are multi-metallic units. These are building blocks that Omar Yaghi stitches together into crystalline sponges using new reticular chemistry. The yellow balls represent the porous spaces that can fill up with water. The background image shows the many cyrstals of MOF that are combined in the water harvester. Credit: UC Berkeley and Berkeley Lab

The system Wang and her students designed consisted of more than two pounds of dust-sized MOF crystals compressed between a solar absorber and a condenser plate, placed inside a chamber open to the air. As ambient air diffuses through the porous MOF, water molecules preferentially attach to the interior surfaces. X-ray diffraction studies have shown that the water vapor molecules often gather in groups of eight to form cubes.

Sunlight entering through a window heats up the MOF and drives the bound water toward the condenser, which is at the temperature of the outside air. The vapor condenses as liquid water and drips into a collector.

"This work offers a new way to harvest water from air that does not require high relative humidity conditions and is much more energy efficient than other existing technologies," Wang said.

This proof of concept harvester leaves much room for improvement, Yaghi said. The current MOF can absorb only 20 percent of its weight in water, but other MOF materials could possibly absorb 40 percent or more. The material can also be tweaked to be more effective at higher or lower humidity levels.

"It's not just that we made a passive device that sits there collecting water; we have now laid both the experimental and theoretical foundations so that we can screen other MOFs, thousands of which could be made, to find even better materials," he said. "There is a lot of potential for scaling up the amount of water that is being harvested. It is just a matter of further engineering now."

Yaghi and his team are at work improving their MOFs, while Wang continues to improve the harvesting system to produce more water.

"To have water running all the time, you could design a system that absorbs the humidity during the night and evolves it during the day," he said. "Or design the solar collector to allow for this at a much faster rate, where more air is pushed in. We wanted to demonstrate that if you are cut off somewhere in the desert, you could survive because of this device. A person needs about a Coke can of water per day. That is something one could collect in less than an hour with this system."

Explore further: Researcher discusses capturing carbon in the presence of water with MOFs and COFs

More information: "Water harvesting from air with metal-organic frameworks powered by natural sunlight," Science, science.sciencemag.org/lookup/ … 1126/science.aam8743

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betterexists
Apr 13, 2017
This comment has been removed by a moderator.
betterexists
not rated yet Apr 13, 2017
SAUDI ARABIA, DUBAI etc., NEED IT RIGHT AWAY !

MATTER OF LIFE & DEATH There !
TheGhostofOtto1923
1.7 / 5 (11) Apr 13, 2017
This will make dr mills suncell totally self-sufficient and with unlimited range as it only needs water to operate.
PTTG
4.6 / 5 (10) Apr 13, 2017
The suncell is a hoax. Ever notice how it's been "six months from sale" for a decade?
betterexists
not rated yet Apr 13, 2017
dustywells
1 / 5 (5) Apr 13, 2017
What happens to the heat entrained in the water vapor? This invention potentially may be more threat to the climate than fossil fuels.
antialias_physorg
5 / 5 (10) Apr 13, 2017
What happens to the heat entrained in the water vapor? This invention potentially may be more threat to the climate than fossil fuels.

Erm ...whut?

1) You have no clue how fossil fuels affect the climate so why do you post?
2) see 1)

(Note that water vapor is also a - albeit much less critical - greenhouse gas. So taking it from the atmosphere can only help with this particular issue)
dustywells
4 / 5 (4) Apr 13, 2017
Erm ...whut?
Water vapor carries the heat that caused the evaporation of water. Condensation releases that heat.

antialias_physorg
4.6 / 5 (9) Apr 13, 2017
Water vapor is a greenhouse gas because it reflects infrared light. Note that a lot of the energy of the light that reaches the Earth's surface (visible and UV) is emitted back as infrared. Water vapor (much like CO2) acts like a blanket by keeping this heat trapped. This is FAR more critical in upping the Earth's energy balance than conversion of water vapor to water (which, in any case, is transformed back into water vapor when you sweat/breathe it out)
TheGhostofOtto1923
2.5 / 5 (8) Apr 13, 2017
The suncell is a hoax. Ever notice how it's been "six months from sale" for a decade?
So... hot fusion is a hoax as well? The cure for cancer is also a hoax? Peace in our time is similarly a hoax? Was the hubble a hoax because it took longer than it was supposed to?

Is anything which takes longer than initially projected a hoax to you simply because you cant hold your water?

I dont think thats a very good indicator of what is a hoax and what is not. How about you?
gkam
2.5 / 5 (11) Apr 13, 2017

We have something real here, not vaporware in the old sense.

The other stuff is science fiction until proven otherwise.
cgsperling
Apr 13, 2017
This comment has been removed by a moderator.
betterexists
not rated yet Apr 13, 2017
Take California Solar for example; California's Solar installations have started feeding so much power into the grid that they have driven wholesale electricity prices at times as low as zero — or even below zero. Solar energy has supplied 40% of California's power needs for the first time at midday on March 11. Total solar capacity in California (for both small scale and utility scale) grew from less then 1 gw in 2007 to nearly 14gw by the end of LAST year.
michael_frishberg
2.6 / 5 (5) Apr 13, 2017
This type device has substantial unintended consequences, too bad it doesn't generate contraception at the same time.
ddaye
5 / 5 (1) Apr 13, 2017
Seems like it might also have applications for keeping interior spaces at specific humidity levels. I could really use a device for this for spaces between the size of picnic coolers and small closets.
sascoflame
1.7 / 5 (6) Apr 14, 2017
This device violates the conservation of energy. It takes 2260000 Joules to convert 1 kg of liquid water at 100 ºC at one atmosphere to 1 kg of water gas. So it takes 2260000 Joules to convert 1 kg of water gas to 1 kg of liquid water at 100 ºC. A kg of water is a liter of water. .627778 Kilowatt Hours (kWh).
Caliban
3 / 5 (4) Apr 14, 2017
We'll have to wait for them to get back to us on what cost scale up to realistic levels of household water supply will cost.

For a typical single family home in the developed world, one would expect it will be a while...
nrauhauser
4 / 5 (4) Apr 14, 2017
SAUDI ARABIA, DUBAI etc., NEED IT RIGHT AWAY !


Nothing is going to fix the problems in the Persian Gulf. Kuwait, Saudi Arabia, Bahrain, Qatar and U.A.E. are desalination dependent to the point salt levels in the PG are up 25% in a couple decades. The presence of fossil fuels permitted growth of a population far beyond regional carrying capacity and they've now hit a hard local limit with fresh water. What is happening in Yemen right now is going to happen to the whole Gulf eventually, and it will be beyond ugly.
jimbo92107
5 / 5 (3) Apr 14, 2017
What a great product for camping or survival!
TheGhostofOtto1923
4.5 / 5 (8) Apr 14, 2017
This device violates the conservation of energy
-So youre saying that catalysts violate the conservation of energy?
jonesdave
3.7 / 5 (6) Apr 14, 2017
The suncell is a hoax. Ever notice how it's been "six months from sale" for a decade?


He's been trotting this scam around for the best part of 2 decades! It's utter lunacy. It relies on hydrogen having quantum states below the ground state!!! Nobody has ever seen this, and it violates everything we know about physics. It will never go anywhere, and has been trashed in the scientific literature.
The reason he is always just a little while from having a commercial product is so that he can keep the investors stumping up the money.
You can see some of the criticism documented here: http://everything...t_Power/
There is a long running thread at ISF, here: http://www.intern...t=315572

TheGhostofOtto1923
3.7 / 5 (3) Apr 14, 2017
Hey dave
The reason he is always just a little while from having a commercial product is so that he can keep the investors stumping up the money
No he is much closer this time.
You can see some of the criticism documented here: http://everything...t_Power/
Youve posted this site before and youve been told that the latest info is almost 10 years old. Is that how old your opinion is?
There is a long running thread at ISF, here: http://www.intern...t=315572
The latest info on this site is 6 years old. I tried accessing earlier pages and got this:

"Reason: service unavailable helper='Webblocker server is not available' details='Porn Blocker and Security'"

-You do understand what the term 'credible source' means?

Why dont you stop posting the same old obsolete shit and research some new criticisms? Theyre readily available you know.
dustywells
5 / 5 (4) Apr 14, 2017
This device violates the conservation of energy.
No, it doesn't. It releases the heat energy into the atmosphere.
Dug
4.5 / 5 (2) Apr 14, 2017
The planet 's surface coverage 71% water. It isn't like there will ever be a planetary shortage, it's just not in the right places and forms. Primary human concern is that much of the planetary water is neither drinkable or usable for most agriculture within current energy conversion paradigms.

There are some very efficient solar stills designs around now - at least for scaled use and are far simpler and more sustainable technologically and material wise than is required for the sophisticated metallurgy technology for the device described above - and it is available now. I recently read about a French design that uses the weight of the water to pull a vacuum in a large evaporation chamber increasing the vaporization and condensation efficiencies significantly. Service fill water and freshwater movement to storage can be pumped used existing solar/battery energy.

Additionally, the articles note of a person needing a coke can of water a day - strains credulity under most cases.
Captain Stumpy
3 / 5 (2) Apr 14, 2017
@p511859
Looks like we have some good Thunderf00t material here.
i sent him a copy of the study
this seems slightly different with different materials but i doubt the whole "liters a day" or whole house water needs claim without a sizable piece of equipment
from the study
Therefore, to predict the prototype water harvesting potential under equilibrium conditions, we extended the desorption time for the simulation, results of which match the prediction from the isotherm (~0.3 L kg–1, shown in the upper abscissa of Fig. 4C). In order to fully utilize the steep step of water uptake in the MOF-801 isotherm, a temperature difference of ~45°C between the condenser and the layer is necessary to achieve desorption at 10% RH
Captain Stumpy
3.7 / 5 (3) Apr 14, 2017
Additionally, the articles note of a person needing a coke can of water a day - strains credulity under most cases.
@dug
i am with you on that, but i think they meant this strictly for a survival under extreme conditions example
i still disagree with it as you would require a mite more in desert heat conditions - but if you could keep yourself out of the direct sunlight and cool, i think this could work
There are some very efficient solar stills designs around now
absolutely

i think something like the Desolenator would be a better investment of time and energy considering ... but that is because most people have at least a brackish supply of water
I recently read about a French design
if you can find a link, i would appreciate it
thanks
sascoflame
not rated yet Apr 17, 2017
The editors of Science X Phiys.org should be removed for publishing a scam. https://www.youtu...p;t=757s
derphys
5 / 5 (1) Apr 17, 2017
Using any thing like LiCl, or others, which absorbs water vapor even in very dry air and cycling to release water by heating in the sun, even slightly concentrated, and condensing water in the cold of the night, quite cold in arid country, kept in a heavy mass of earth protected from the sun of the day, you make liquid water, with an efficiency useful..
You cool in the night the ground with the infrared send to the arid sky and you absorb the few air water vapor in LiCl and in the day the sun heat this LiCl to extract water vapor which is condensed in the cold ground protected from sun of the day.
This works and is not a scam to obtain water using basic physical laws using sun heat, around 100W/daym2 maximum, over day and night. with the efficiency of a typical simple heat sun collector.
derphys
5 / 5 (1) Apr 17, 2017
Any system of this kind, using anything absorbing water ( Licl or other salt or metal organic framework, zeolite, .... ) need a hot source with sun and a cold source which can be obtained in the night which cools strongly in arid contries sending infrared light to the open sky.
Thus carefuly made this is not a scam, using the cool of the night, kept from night to day, in some isolated mass of earth ( several cubic meters ) as well the heat of the sun of the day kept in another isolated mass of earth.
dustywells
5 / 5 (1) Apr 18, 2017
About 3 liters per day, maybe a little more in summer, is not a lot of water for most westerners.
"There is a lot of potential for scaling up the amount of water that is being harvested... ...Wang continues to improve the harvesting system to produce more water."

It all depends on what you read into the article.
murraylo9
5 / 5 (1) Apr 20, 2017
The suncell is a hoax. Ever notice how it's been "six months from sale" for a decade?

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