A Device That Can Pull Drinking Water From the Air Just Won the Latest XPrize (fastcompany.com) 359
Two years ago, XPrize, which creates challenges that pit the brightest minds against one another, announced that it would give any startup or company $1 million that can turn thin air into water. This month, it announced that the challenge has been concluded. From a report: A new device that sits inside a shipping container can use clean energy to almost instantly bring clean drinking water anywhere -- the rooftop of an apartment building in Nairobi, a disaster zone after a hurricane in Manila, a rural village in Zimbabwe -- by pulling water from the air. The design, from the Skysource/Skywater Alliance, just won $1.5 million in the Water Abundance XPrize. The competition, which launched in 2016, asked designers to build a device that could extract at least 2,000 liters of water a day from the atmosphere (enough for the daily needs of around 100 people), use clean energy, and cost no more than 2 cents a liter.
"We do a lot of first principles thinking at XPrize when we start designing these challenges," says Zenia Tata, who helped launch the prize and serves as chief impact officer of XPrize. Nearly 800 million people face water scarcity; other solutions, like desalination, are expensive. Freshwater is limited and exists in a closed system. But the atmosphere, the team realized, could be tapped as a resource. "At any given time, it holds 12 quadrillion gallons -- the number 12 with 19 zeros after it -- a very, very, big number," she says. The household needs for all 7 billion people on earth add up to only around 350 or 400 billion gallons. A handful of air-to-water devices already existed, but were fairly expensive to use. The new system, called WEDEW ("wood-to-energy deployed water") was created by combining two existing systems. One is a device called Skywater, a large box that mimics the way clouds are formed: It takes in warm air, which hits cold air and forms droplets of condensation that can be used as pure drinking water. The water is stored in a tank inside the shipping container, which can then be connected to a bottle refill station or a tap.
"We do a lot of first principles thinking at XPrize when we start designing these challenges," says Zenia Tata, who helped launch the prize and serves as chief impact officer of XPrize. Nearly 800 million people face water scarcity; other solutions, like desalination, are expensive. Freshwater is limited and exists in a closed system. But the atmosphere, the team realized, could be tapped as a resource. "At any given time, it holds 12 quadrillion gallons -- the number 12 with 19 zeros after it -- a very, very, big number," she says. The household needs for all 7 billion people on earth add up to only around 350 or 400 billion gallons. A handful of air-to-water devices already existed, but were fairly expensive to use. The new system, called WEDEW ("wood-to-energy deployed water") was created by combining two existing systems. One is a device called Skywater, a large box that mimics the way clouds are formed: It takes in warm air, which hits cold air and forms droplets of condensation that can be used as pure drinking water. The water is stored in a tank inside the shipping container, which can then be connected to a bottle refill station or a tap.
It's called a dehumidifier. (Score:5, Insightful)
It's called a dehumidifier.
Re:It's called a dehumidifier. (Score:5, Funny)
Or a windtrap, if used on Arrakis.
Re:It's called a dehumidifier. (Score:5, Funny)
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I think you should call child protection services.
Re:It's called a dehumidifier. (Score:4, Funny)
Can you speak to it?
Sir, my first job was programming binary loadlifters—very similar to your vaporators in most respects.
Dehumidifier scam (Score:3, Funny)
it's a new type of scam aimed at investors.
Let's call it "Dehumidifier as water supply investor scam"
or shorter : "Dehumidifier scam"
Re:Dehumidifier scam (Score:5, Funny)
It condenses money out of thin air!
=Smidge=
Re: Dehumidifier scam (Score:3)
It's a very old type of scam. I remember reading about "Krupec Pyramiden" (Google it) when I wasn't even a teen yet.
Even that I only know about because it was local, there are probably thousands like it. Extracting water from the air is a favourite of "inventors" who know too little physics to know how little they know. And also of scammers who do know, but won't give up the prospect of getting rich just because their idea didn't work.
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Not really that new of a scam, actually:
https://www.google.com/search?... [google.com]
Whatever you believe about crowdfunding, Triton and Fontus were straight-up scams from the start, backed by fancy kickstarter videos.
Anymore, the more polished a kickstarter video looks, the less likely I am to trust that the product is real.
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It also captures the water gained by pyrolysis of wood. (CxHx + O2 -> H2O + CO2)
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Indeed. A lot of people don't like the YouTuber Thunderf00t, for good reason, but he's done some good videos debunking the concept. Starting with the WaterSeer [youtube.com], Zero Mass Water [youtube.com] and of course the self-filling waterbottle [youtube.com].
TL;DR: yes, it can be done. Yes, it's been done. But it's cheaper and easier to load a tank of water on a helicopter or truck and take it to where it needs to be.
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I watch his videos and agree with him most of the time. That said, he comes across as a bit of an asshole. Oddly, in videos where he has a talk with an ideological opponent, he's clearly not an asshole in one-on-one situations... these tend to be very civil affairs. But for a looooong time he was constantly clashing with creationists (among other religious people) and then feminists. Even if you agree with him, it was kind of repetitive, part of an echo chamber that I'm not really part of, and detracted fro
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Well, it depends on your political viewpoints, but he has a little something for everyone.
He's vocally atheist, which means his mere existence offends the invisible sky wizard worshippers.
He's especially critical of Islam, which enrages leftshits crying about muh Islamophobia.
He's anti-Brexit, which makes many a right-winger angrily slam their keyboards in their moms' basements.
He's anti-feminist and was involved in Gamergate, which caused many a hipster's manties to mysteriously twist.
He debunks scientific
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And now you see why right-wing, alt-right, and brexit people get so pissed off about him. He made the cardinal sin of not toeing the line on every single policy.
Personally, I ignore the political videos, they are not that interesting. I think he worked at an EU funded science lab in the past, so he has a vested interested for keeping the EU together.
Once politics is over, debunking bullshit is the next big youtube frontier.
Oh, and does a lot of debunking videos of Hyperloop, which is sure to piss off a huge
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Which century would that be?
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I do wish he'd stick to his field, though. He's a great debunker, as he knows how to use the laws of physics to utterly destroy a scam product - but when talking about politics, he's really no more of an expert on social issues than any random person grabbed off the street.
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It is actually why I stopped watching a lot of 'rat
Re: It's called a dehumidifier. (Score:2)
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I would be interested in learning what good reasons people don't like Thunderf00t for?
Because using zeroes for Os is cloying.
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A compression based dehumidifier is very inefficient. This system is pretty slick; they vaporize biomass (releasing the moisture content) and turn it to a charcoal for fertilizer, making the process carbon-negative, according to TFA.
The last part raises my eyebrows a bit-- they seem to claim they aren't releasing CO2, but it isn't clear where the actual energy input comes from (chemically). Presumably it is just a portion of the biomass that is burned.
or an airconditioer (Score:2)
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But it is carbon neutral. In fact burning oil is also carbon neutral. The universe is zero-sum.
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I'm on the gasifier team. Let me explain the claim (Score:5, Informative)
I'm on the gasifier team from All Power Labs, the company that provided the gasifier genset to the Skysource/Skywater Alliance. Bear with me as I correct some misconceptions here.
Firstly, I would like to make clear that we're not cutting down fresh trees to do this. It is not cost-effective nor sustainable to cut down fresh trees to gasify, especially when there is so much woody biomass waste. There are plenty of companies paying folks to get rid of their biomass waste, including wood chips and nut shells.
Secondly, a bit of nuance required. The machine is not "burning wood"; it is gasifying wood. Wood consists of roughly 80% volatiles, 20% fixed carbon. The gasifier pyrolyzes the wood, which produces tar gases (wood smoke); the tar gases are partially burned while thermally cracking the rest, and the combustion products are percolated through the charcoal. A portion of the charcoal is consumed via reduction reactions that convert the H2O and CO2 from burnning the tar gases into H2 and CO gas, which are then sent to power the engine. Essentially, the gasifier is burning the tar, and un-burning it with the char, then re-burning it in the engine. The heat that would otherwise be dissipated is being used to drive the CHP system.
See our explanation of how gasification works:
http://www.allpowerlabs.com/gasification-explained
Thirdly, the carbon-negative claim comes from the following accounting: the biomass waste almost entirely reverts to carbon dioxide via decomposition, but when run through gasification, a significant fraction of the fixed carbon portion is not consumed, and is pushed out of the gasifier as charcoal. Since charcoal is stable and does not revert to carbon dioxide without combustion, it is effectively removed from the carbon cycle.
Furthermore, we specifically save the charcoal for use as biochar. We send the char through the compost so it can absorb nitrates and phosphates and other nutrients that tend to leach out of compost as leachate. This also fills the char with compost microbes, and conditions the surface to have a humus like quality, which enhances the cation exchange capacity and water holding capacity of soil that is amended with this material. The effect that biochar has on soil parks even more carbon in the soil for the long term. Humified biochar (co-composted biochar) dramatically stimulates the release of plant root exudates (roughly 10 units of exudates per unit of black carbon—humus or humified biochar) and holds on to these exudates for resident microbes to use. These root exudates then stimulate a dramatic increase in soil fungal mycelia (also roughly 10x). This is sometimes referred to as the carbon multiplier effect: 1 unit of black carbon supports 10 units of green carbon (plant exudates) on an ongoing basis, which stimulates the growth of 10 units of white carbon (fungal mycelia).
Fungal mycelia contain a lot of glomalin, a glycoprotein that is a significant carbon sink. Glomalin remains in soil for an estimated 50-60 years.
See this piece from the USDA on Glomalin as a carbon sink:
https://www.ars.usda.gov/news-events/news/research-news/2008/glomalin-is-key-to-locking-up-soil-carbon/
See this piece on how biochar stimulates arbuscular mycorrhyzae (soil fungi symbiotic with plant roots, exchanging phosphorous for plant exudates):
https://www.sciencedirect.com/science/article/abs/pii/S0038071714002211
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Re:It's called a dehumidifier. (Score:5, Interesting)
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The trees don't have to start out dead - cutting them down will kill them quite effectively as well. So long as new trees grow to take the old one's place, and more-than-none of the carbon in the original trees is turned into biochar, the overall process is carbon-negative (assuming no fossil fuels are used in the cutting and transportation process - otherwise you need to increase the amount of biochar produced to offset that).
It also doesn't have to be trees - any woody, or even just hot-enough-burning bi
Wrong explanation. (I'm on the gasifier team) (Score:5, Informative)
The carbon-negative claim is based upon the supposition that in its deployment, the magic water box would occasionally be near a forest with abundant dead trees that are at risk of spontaneous atmospheric carbon liberation.
(Disclosure: I am part of the team that provided the biomass gasifier.)
This is an incorrect claim. The carbon negative claim comes from the fact that the process of gasification produces charcoal as a byproduct, and charcoal does not revert to carbon dioxide without combustion (somewhat simplified but sufficient summary), whereas the biomass nearly entirely reverts to carbon dioxide in the course of decomposition. The more thorough explanation is that the charcoal has a labile (biodegradable) fraction and a recalcitrant fraction. The labile fraction takes years if not decades to decompose, and the recalcitrant fraction essentially doesn't participate in the carbon cycle.
See this on the processes of gasification:
http://www.allpowerlabs.com/gasification-explained
The charcoal is sent through the compost and used as biochar. When used in this way, it enriches the soil for the long term and results in several effects which cause the soil to take up more carbon—firstly, by increasing the soil's capacity to hold on to plant root exudates while stimulating the production of these exudates, and secondly, because the plant exudates stimulate the growth of fungal mycelia.
Fungal mycelia contain a glycoprotein called glomalin, which has a long soil lifetime—roughly 50 years. In this way, the production of charcoal and its use as biochar actually takes carbon out of the carbon cycle and parks it in the soil. Soil fungal glomalin is one of the potential carbon draw-down solutions seriously being considered to draw down carbon dioxide levels from the atmosphere.
See this about glomalin as a carbon sink:
https://www.nature.com/articles/s41598-017-12731-7
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Hookers and Blow it is then.
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FTA:
When the gassifier is filled with wood chips, coconut shells, or whatever biomass is locally available, a process calls pyrolysis vaporizes that material. That makes the system hot and humid, the ideal environment to run the air-to-water machine. As it generates power, it also produces biochar, a charcoal that can be added to soil to store carbon and help plants grow.
Re:It's called a dehumidifier. (Score:5, Insightful)
The growing plants also need water ...
If there is sufficient groundwater to allow renewable forestry resources to grow, there is sufficient ground water for a pump ... which isn't that much work to install with the amount of equipment you can fit in a shipping container.
Re:It's called a dehumidifier. (Score:5, Interesting)
True enough, assuming someone competent enough to dig/drill the well is present. Although I can't speak to people everywhere, it seems like most USian folks displaced by natural disaster seem to sit around and wait for someone to deliver salvation in frustration-free packaging.
This system can also be deployed to regions without plentiful carbon rich dead fall and powered by solar collectors and batteries.
Re:It's called a dehumidifier. (Score:5, Insightful)
More a matter of "those types are the ones who make the news."
Re:It's called a dehumidifier. (Score:5, Insightful)
Be fair: Anyone who has lived their life in the urban or suburban region of a modern industrialized country is going to be in the same situation, and for most it is the appropriate action to take. They can know with confidence that, while things are looking pretty bad right now, there's a concerted rescue effort underway and help will arrive long before they have to resort to eating the family dog.
So it doesn't pull water from the air. (Score:3)
It burns the hydrogen out of timber, and then condenses some of the water released. I mean, interesting concept, but it doesn't really fill the brief.
That said, actually filling the brief is probably impossible. To fulfill the brief, you'd have to, some way, get rid of the 5GJ of latent heat energy per day - in addition to the energy you add to run your equipment. That's 58kW, constantly.
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It burns the hydrogen out of timber, and then condenses some of the water released. I mean, interesting concept, but it doesn't really fill the brief.
That said, actually filling the brief is probably impossible. To fulfill the brief, you'd have to, some way, get rid of the 5GJ of latent heat energy per day - in addition to the energy you add to run your equipment. That's 58kW, constantly.
Amazing isn't it? The whole concept belongs on Youtube with the perpetual motion and the "heat your house with 2 tea candles and a clay flowerpot" videos.
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So it doesn't "pull water out of the air" ... at least not until the water from burning the biomass is released into the air.
Comment removed (Score:5, Informative)
Re:Waiting for Dave's rant on this (Score:5, Informative)
Thundef00t has also shit all over various dehumidifier scams in youtube rants. Water from thin air is not feasible in the locations where it is needed. Arid regions have, wait-for-it, not enough water in the air.
Re:Waiting for Dave's rant on this (Score:4, Interesting)
If only there was a device that could--can't think of a good new verb for it--lets say, "move" water from places we do have, and then it could travel through some kind of cylindrical containing device that held the water molecules in, and pushed this liquid medium through the hollow cylinder to the place where its needed.
How do they move oil? I can't think of it. But it's like, they send oil thousands of miles.
Too bad I'm pretty sure it only works for oil and not for water because nobody makes any goddamn money from saving lives.
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People need a lot less oil than they need water. Transporting water by pipe quickly becomes infeasible.
Re: Waiting for Dave's rant on this (Score:5, Funny)
I don't know, it's how I get most of mine.
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People need a lot less oil than they need water.
That's true. I don't *need* any oil, but I like to keep some in my car at all times.
Transporting water by pipe quickly becomes infeasible.
Most every building I've ever been in has water piped in. So, it's somewhat feasible.
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And as usual, especially for Dave Jones, both have been debunked. Seriously, apart from Batterizer I don't think Jones has ever once been right in one of his debunking rants.
In this case they are applying the wrong test to the device. If you read TFA you can see that it needs a lot of energy to work, which they suggest supplying via a biomass generator or solar+battery. As such it's not designed to run continuously or even be particularly efficient, it's just designed to supply emergency water for a short p
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Seriously, apart from Batterizer I don't think Jones has ever once been right in one of his debunking rants.
What else has he been wrong about?
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He did a video about the solar cycle way prototype in Europe. He failed to consider the costs of installing and maintaining a normal cycle way, and then a year later the numbers released for it debunked his pessimistic estimates. His speculation about the surface durability were proven unfounded too.
The biggest issue of course is that he was looking at a prototype, considering the cost of prototype parts and deployment, so even if his guesses had been right his point would have been irrelevant.
I'm not sayin
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The multimeters thing is interesting, considering how bad his own ones are. Poor quality manufacturing combined with design flaws does not make a good product.
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Arid regions have, wait-for-it, not enough water in the air.
Not all regions where water is required are arid. There are many reasons people could be in need of water, not the least of which being a contaminated local supply.
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Thundef00t has also shit all over various dehumidifier scams in youtube rants.
Yeah, but he's not a credible source, and Dave is.
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Those 'water from thin air' systems do work, it's the cost and power consumption that's a problem. The one that is supposed to fill a bottle of water in a couple of hours from a tiny 5W solar panel, for example.
There's no reason why you couldn't set up a big system with 20 kW of solar and get useful amounts of water out of it, the problem is feasibility. It's usually cheaper to put a tank of water on a truck.
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It's usually cheaper to put a tank of water on a truck.
This is exactly the point. Nobody is saying that dehumidifiers don't work. They are saying there is no way to use them as a water supply in any way close to being economical. Anyone that claims otherwise failed basic science class or is lying to you.
Physics, it works! (Score:5, Informative)
So a fairly large 4x4 meter solar panel (that would cost around $5000 to install) will produce around 50 liters of water per day (that's an optimistic estimate), or around 18 tons of water per year. If usable life of the device is 10 years then we're looking at about 200 tons for about $5000, or 4 cents per kg.
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Condensing water produces heat energy. It's why your can of ice cold beer warms up. Water in the air condenses on the can, adding energy to the can and warming up the beer. So you don't need to produce the latent heat energy of evaporation, you just need a means to dissipate it to maintain the temperature of the chilled condensing surface.
To dissipate the energy that's absorbed, all you need is a heat pump (and a suffic
The other half of the technology (Score:5, Informative)
It's an old idea (Score:5, Informative)
Nothing new here folks.
Commercial Atmospheric water generators have been around for a long time
see https://en.wikipedia.org/wiki/... [wikipedia.org]
The military routinely use them in desert areas.
They do take a fair amount of energy to run, but not as bad as you might think if transverse flow heat ex changers are used to recover lost heat (and cold).
quadrillion? (Score:2)
Umm, a quadrillion has 15 zeroes, not 19.
If Zenia Tata doesn't even know that all those *illion numbers are multiples of three zeroes, should she really be "chief impact officer" of the x-Prizes?
This again? (Score:2)
Don't we already have enough scam artists peddling this? Elementary physics will tell you that it doesn't work. Pulling water out of air works. Yes. But you need to "harvest" a LOT of air and dehumidify it. There's even already machines that do that. They are called dehumidifiers, aptly named. And that takes a LOT of energy. If you plan to do this by solar power, be prepared to drop some pretty penny (and dedicate some real estate) to collecting that energy.
This is only feasible in areas where water is scar
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That's what the last paragraph was supposed to say. It's only useful in deserts and other areas where you don't have easy access to drinking water, and there, the air contains little water.
And yes, the hygiene aspect is another thing that wasn't even touched yet.
'Clean energy' (Score:2)
"From a report: A new device that sits inside a shipping container can use clean energy to almost instantly bring clean drinking water anywhere"
In Maine, at least, some legislation was enacted to discourage using wood in a variety of systems to heat homes. IT seems that some of those were pretty dirty. Gasifiers were pretty large scale, and usually used a lot of otherwise unused biomass. And were, as mentioned elsewhere, mot often located where the biomass was. One I knew of was located at the chip and lumb
Now all they need is a water transportation system (Score:2)
Thunderf00t is going to lose his shit (Score:2)
https://www.youtube.com/watch?... [youtube.com]
Mars? (Score:2)
I have that already (Score:3)
It's my air conditioner.
Will they work on Mars? (Score:2)
There is water in the Martian atmosphere [wikipedia.org] so can we send some of these to Mars now, and have them build a store of drinking water for us when we get there?
Re:Some quick sums (Score:5, Interesting)
That's not infeasible. It's just incredibly inefficient, that's all.
1500 times 67.6 cu m is just over 100,000 cubic metres.
I just pulled up a building-site fan - Clarke CAM110 30â Drum Electric Fan (110V) - 350W
Max air flow 200m3/min.
So it would take 500 minutes to pull through that much air, which is just 8 1/3 hours. So just a bog-standard, low-power building-site fan on the side, ducted to pull fresh air in, circulate it through the system, and then blow it out, would be able to do three times that in a day. I'm sure a lower power solution would exist to do just what the system can take and no more.
Take into account the halved humidity and it's still viable.
The question is really whether or not after pumping 100,000 cubic metres of outside air through it the water is contaminated with all kinds of crap, not to mention having to clean and change filters constantly. That kind of fan would build up a layer of dust-strands, hairs, etc. with in days even in a relatively clean air, then you're blowing that through a system trying to collect water from it, and having to filter it. Things like airborne dust etc. are going to need lots of filters in the path of both the air, and the water collection.
That's not to say it's completely ridiculous. It would, indeed, be able to make water out of thin air. I would just posit that it's probably easier and cheaper to ship a few bottles, or dig a well.
Especially if you consider that to be self-powered, it probably needs an entire roof of solar - anywhere people are desperate for water, shipping an entire container of very expensive (and valuable, which is different) electronics and metals out there probably is going to be subject to short-sighted selfishness, otherwise known as theft. Solar panels and refrigeration equipment like that is going to be worth a fortune in such a place.
Though it could probably "profit" after a number of years of flawless operation without maintenance costs, I could easily imagine that production costs, transport, maintenance, etc. would make it less viable than just shipping some Evian or a well-borer.
And it has zero value in any place that's not literally desert... nobody's going to buy an incredibly expensive box in order to get a few thousand litres out of it if there's a river even within a hundred miles. Thus the market is really quite tiny.
It's the kind of thing you'll see in a science museum in 50 years, just sitting them offering a free cup of water to visitors.
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It's worse than that even. A lot of desert regions are a desert for reasons i.e. there is no moisture at all including the air. I happen to live in a desert humidity can typically be 10 to 15 percent. So at what point is the device not economical i.e. it actually is less expensive and more efficient to just haul some water in on a truck?
I personally am glad to see the technology developed and do think it could be useful in some emergency situations. But it would be interesting to understand the economics an
Re:Some quick sums (Score:5, Interesting)
"The 378L/day one (at 50% RH) needs 4.2kW"
The bigger ones have 30KW diesel generators in them.
This isn't "water for free, forever", this is "a pittance of water at ongoing costs, fuelled by oil or wood or similar burning".
Sure, you can slap some solar panels and maybe you'd get your 4.2KW out of them... but then the purchase cost is going to be prohibitive and the running costs are going to be non-zero even then (water tanks and solar aren't the kind of things you can just leave unmaintained in a desert forever). It also makes it a target ripe for theft.
I would hazard that if you put a 30KW diesel generator, plus fuel, or 4KW of solar panels, etc. in a place where people can't afford/obtain water, it won't be long before bits "go missing" and end up on the black market in exchange for... well... some water, eventually, most likely.
Re:Some quick sums (Score:4, Interesting)
From their own FAQ:
What happens when thereâ(TM)s low humidity in the air?
When the humidity is low, all air to water machines are challenged. Skywater machines are not designed for dry or cold climates and are not marketed there.
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From their own FAQ:
What happens when thereâ(TM)s low humidity in the air? When the humidity is low, all air to water machines are challenged. Skywater machines are not designed for dry or cold climates and are not marketed there.
And that is actually the real problem -- low humidity air. If the area has abundance of water in the air, it implies that plants/trees in the area shouldn't die by drought. The only thing it may solve is certain contamination (which does not happen in the air, e.g. heavy metal) could be eliminated. However, this invention doesn't really solve the main issue but rather an add-on as another commercial product.
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Self sustaining? How much wood grows in an area with a recurring water shortage?
Re:Some quick sums (Score:5, Interesting)
Have a look at their web site: https://islandsky.com/products... [islandsky.com]
They have a range of these things and seem to be selling a reasonable number. Most are much smaller than required for the X Prize. So they stuck a few of them in a shipping container, and added a biomass generator to meet the carbon neutral / low running cost requirements.
You need a lot of energy for those things. The 378L/day one (at 50% RH) needs 4.2kW. They claim that biofuel gassifiers are already in use in India.
It's marginal but interesting. Their use case if where there is local water available but over-use is causing problems like acute droughts.
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The system pulls the moisture out of the biomass, in addition from what it gets in the air.
As for the complexity, if you ever get the chance go to an air separation plant. Atmospheric air in (plus a few megawatts of electricity), oxygen, nitrogen, argon, water, and some nasties out. Filtering the air is the easy part. The problem is that straight dehumidification via compression and refrigeration is thermodynamically inefficient.
Re:Some quick sums (Score:5, Informative)
100 % humidity means 30 grams (0.03l) of water per cubic meter. Today in the UK we are at 70%, so lets say theres 20g on a bright autumn morning.
You'd be lucky, 100% humidity is only 30 grams at 30 degrees C [engineeringtoolbox.com]. At 10 degrees, more typical for a UK autumn morning it is less than 10g per litre. I Nairobi it is 20 degrees C now so your figure is closer there (17g/m^3 100% humidity).
Re:Some quick sums (Score:5, Insightful)
Water content depends on the temperature too, so you only get 30 g per m^3 at 30 deg and 1 atm. If the temperature is lower you get less. So your estimate of 20 g in the UK is most likely too high (unless it was 30 deg near you). Yesterday it was 18 deg and 64% RH at my local RAF base, which gives only 10 g/m^3.
Anyway, take Nairobi, today it'll be 24 deg and 38% RH, which gives 9 g/m^3, in the evening it'll be 18 deg and 72% RH, which gives 11 g/m^3 (about the same which makes sense). So the volume flow through the container will need to be 200,000 m^3 per day, which is about 3,000 cycles per day. To be fair, while that sounds like a lot, 200,000 m^3 per day is only 2.3 m^3/s. To put that into perspective that's 1 m/s airflow through a 1.5 x 1.5 metre aperture.
The other thing to look at is the power consumption - a portable "industrial" dehumidifier extracts 70 litres / day, consuming 1.35 kW - that is 0.466 kWh / litre. We'll be generous and assume this device is twice as efficient, so that gives us 466 kWh to provide 2,000 litres of water, which is just under 20 kW power consumption.
The numbers don't sound altogether unreasonable. Unlike so of the other water out of air "solutions" - *cough* WaterSeer - they're not assuming they can do it passively, so that's a start...
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That 2 cents per liter is cheap, no?
No, not cheap at all, for water.
For comparison desalinization technology currently produces water for 0.2 cents per liter. This water-from-the-air process produces water at the cost of $20,000 per acre-foot, to use the U.S. unit of measurement for water systems. Not sure what water at this price is good for. Nearly everywhere, no matter how far inland, desalinizing seawater and pumping it to them would be much cheaper.
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I believe the water cannot be drunk without adding some minerals.
Of course it can, though you do need trace minerals somewhere in your diet!
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As long as you eat something during the day, you should be okay. And if you don't have food, you have a bigger problem than lack of minerals.
Re: Demineralized water ? (Score:3)
I believe the water cannot be drunk without adding some minerals.
That's an old urban legend which has gotten more and more silly with each retelling. No, there's nothing wrong with drinking distilled water. You get a lot more minerals via the food you eat than from the water you drink.
Re: It'll never fly (Score:2)
Hard to believe that there are enough idiots on Slashdot for this to get nodded to +1.
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>> It'll never fly
A flying dehumidifier
Now that's a good concept !!
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It's been done before:
https://en.wikipedia.org/wiki/... [wikipedia.org]
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The problem is, water by dehumidifier is expensive, power-wise and doesn't really produce drinkable water.
Open up a dehumidifier sometime. Look at all the crap built up in there.
That's all particulate matter falling out of the air during the dehumidification process.
You REALLY don't wanna drink that stuff.
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Small devices for extracting drinking water from the air already exist, but they are fairly expensive to run. This devices presumably changes that, if the resulting water really only costs $0.02/l
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You don't seem to understand. Ambient air is DIRTY.
The cost of regular filter replacement ALONE will drive the price point of the water up beyond the requisite level.
Re:It'll never fly (Score:5, Insightful)
In addition, filtering the water is a very simple thing to do.
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The choice is not between no water and the dehumidifier water, it is between dehumidifier water and some more cost effective way of delivering water.
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You're only seeing the macro level stuff.
The other stuff in there makes that water VERY unhealthy to drink.
Cloth filter (Score:3)
Is it the sort of matter that four layers of sari cloth [wikipedia.org] can filter out?
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That'll get all the larger particulates out.
The smaller stuff? Probably not.
And the cost of regular filter replacement drives the costs up.
Re: It'll never fly (Score:2)
Not actually true (not even close) but they do apparently have a 27% obesity rate, which is more than I would have thought. Definitely the idea that they're "starving" is blatant nonsense.
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But get burned to death.
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