The Water Abundance XPrize winner makes water from air
fastcompany.com
fastcompany.com
Or in other words, this thing only makes water when you probably don't need water.
Blow some nice 90 deg F 20% humid air past those coils, and you'll be blowing out a lot of 80 deg F 25% humid air out on the other side, getting bupkis for actual produced water, but sucking down plenty of juice. Slow down your intake fan to almost zero, and now your water produced goes up from zero, but the slowest of trickles.
Gotta love all that ozone generator carbon filter garbage on the business end. It's all just bells and whistles to put lipstick on a three-legged pig.
Living in California recently I constantly see the weather forecast claiming 70-90% humidity and yet the area is basically a dessert with almost no rain. I suppose there are many more areas in the world like that.
https://en.wikipedia.org/wiki/Sky_island
(This is also why people keep building houses in fire danger zones: the forests have a nice climate, but they burn. The flat areas don't burn, but they're inhospitable.)
The discussion was about how much work is actually required to condense the water vapor. The fact is that it is thermodynamically possible to MOVE more heat energy (Q) than work (W) applied. The efficiency of heat movement is dependent on temperature gradient but is more than 100% efficient. So as bizarre as this sounds it actually requires effectively zero work to condense water from the air at 100% humidity.
http://www.sfu.ca/~mbahrami/ENSC%20461/Notes/Refrigeration%2... http://hyperphysics.phy-astr.gsu.edu/hbase/Kinetic/watvap.ht... this shows that its quite large amount Efficiency fridge = 1 / ( Th / Tl - 1)
There is actually way more water in the air than 0.04 grams... i think this is because liters not m^3 for 1m^3 there is 30 grams at 30 degrees and 17.3 at 20 degrees. its at least ~15/10 - > 1.5 grams per Centigrade Say we do small diff of 4 degrees, 30 to 26. We gain 1.5 * 4 = 6 grams / m^3 To do this we need to cool 1m^3 water at 30 to 20. Now this is tricky because humidity but https://www.engineeringtoolbox.com/heating-humid-air-d_693.h... h = 1.01 (kJ/kg.oC) t + x [1.84 (kJ/kg.oC) t + 2502 (kJ/kg)] x is relative weight so its actually small like 0.03 so it changes the result very little h = 1.06 (kJ/kg.oC) t + x 2502 Kj/kg partial diff with t gives us 4.24kJ/kg change for cooling the air (sensible) partial diff with x gives us (0.006kg delta) 2500 - > 15kJ/kg for this 4 degree change for condensation with 6g/m^3 of water Since the cooling of air that didnt result in water is reclaimable energy lets ignore it Now efficiency of this heat transfer 1/ (303.15 / 299.15 - 1) = 75x heat transfer efficiency. Does this make sense? we know heat pumps are amazing :) so per gram its like 15kJ/6g = 2.5kJ/gram -> this is really expected as 2.3MJ/kg from original video!
However this heat (Q) is moved via work (W) at 75x rate This means to get 1kg (1L really) it only takes 30KJ So at 15watts (J/sec) -> 2000sec -> 33 min Perhaps this wont work because the MASSSIVE heat sink required :)
How much air needs to be moved? we get 6 grams for each meter cubed of air. Not great thats about 166m^3 of air that needs to filter. https://www.amazon.ca/Ultra-Strong-DC12V-Cooling-200CFM/dp/B... 200CFM -> 5.66 m^3/min 60 min/h = 339 ... this is double what we need. its about 1.6A 12v = 15 watt... but its more than we need. Half it?
Perhaps not! Thanks for running the numbers.
I have a unit in my garage that can actually produce water at less than 10% relative humidity, moves a lot more air so it has more chances to actually capture the water, and smokes these other units under price/performance, particularly when tested in a desert. It's not a dehumidifier-based system. It's also cheaper to build.
Email me for details.
> Thanks for reaching out. Mine uses a deliquescent salt, which requires no energy to absorb water from the air. It's pretty messy, but does the job. Getting the water back out is where the energy is required, and this is non-trivial, but still far better than those dehumidifier approaches, which are unfortunately the perpetual motion machines of our era.
Here is the entire email chain between myself and mchannon: https://go.eligrey.com/t/mchannon-email
I could post all the stuff publicly, but then I’d get more downvotes, because a lot of forum users enforce the norms they like.
I see the number of points in my posts like this one jockey up and down repeatedly, meaning equal double-digit numbers of readers approve and don’t. Being able to follow that history would prove fascinating, but it’s not a feature on HN.
I’ve even attracted a following of a couple of readers who downvote anything I post.
So it’s with the norm—enforcing downvoter in mind when I want to reach out.
Share away. I can’t even give my technology ideas away.
I would never have guessed that he has a PhD in chemistry... he comes across as rather off his rocker
I think it's his rhetoric - there's some substantive argument under the surface but it gets washed out with all the aggression and rhetorical fallacies.... it's very schizophrenic...
His aggressive diatribe manner of speaking seems all too ubiquitous these days, as we find ourselves conducting the vast majority of our communications with the 'hivemind' on platforms where ability to attract attention wins out over quality discourse.
And it's just fucking impossible to have any real conversation in that context. There's no room to entertain subtleties, the higher-order structure of the subject, if you will.
For instance.... he makes it out like everyone involved in this prize is absolutely clueless about thermodynamics and that there are no conceivable advancements to be made for this particular scenario because thermodynamics.
Bullshit. There's plenty of innovation to be had. You can take advantage of daily temperature swings, use a ground-source heat pump... and almost certainly current humidifiers aren't operating at the thermodynamic limit; there's probably work to do in developing better materials, optimizing the design for efficiency, etc
I tried to find accurate information on the technology and how they differentiate from the regular old dehumidifier spiel when I first heard about the prize, even spending a few minutes on Google scholar searches for their contributors. It was all drowned out by marketing materials and fancy graphics.
On one side we have a person with a Youtube brand that lives off of these kinds of debunkings, including their over the top tone. On the other side we have multiple companies with a product and accompanying marketing budgets. Both clearly lacking in room for discussion and subtlety. Could the youtuber get their point accross more objectively and clear? Sure. Would somebody listen or even discover their argument? I kind of doubt that. Just like the product would not gain traction from scientific papers alone.
Trying to make my point clearer, I do not feel like that the Youtube person is solely at fault for a weirdly framed discussion here. If the XPrize winners have more innovation to show than combining two technologies that they seem to have used before they should clearly communicate that, including scientific analysis that are easy to discover. They got a prize for a product that claims to be better than competition with similar tech in a space that previously saw players that absolutely were pure snake-oil. Just put facts next to your pitch decks and fancy marketing materials people.
If anyone is informed about water, it would be great to get a little more context, for example what other solutions like desalinization and other dehumidifiers cost in energy and dollars. (Yes, obviously nothing is going to be as cheap as putting a pipe in a river.)
For example their FAQ says they use less than half the power of their competitors. That seems like a huge advance. And is $.02/liter amazing or just slightly better?
But look, our PMM is producing this many volts! And it works great on paper too!
I haven't seen any data or reports to show this competition actually tested built units and measured both their water output and energy consumed, and did so in a variety of climates. In areas where the mercury has gotten below freezing, for instance, there is no water in the air, and yet, we're supposed to believe these snake oil machines are producing 2000gal/day for $0.02 each, even there.
"If there is a frozen towel in the mountains, is there water in the air if there is no one there to measure the humidity it produces?"
Assuming there were millions of frozen wet towels in such conditions, any sublimated towel ice would rapidly drop back out of the air as frost.
https://www.businesswire.com/news/home/20170927005546/en/3-B...
From what I can glean online, the 150 gal/day unit costs $18k usd + $150-$300 in electricity a month if run 24/7 at $0.10Kwh. Ignoring electrical costs, it would take 1581 days to reach $0.02/liter. In that time you would use up $7.5-15k in electricity.
The best estimate I could find is that the average US household uses 240 gal a day.
A friend of mine had to drill a 980 ft well through bedrock. A well this deep requires a much stronger pump and more electricity. They are on their 2nd pump. I should ask them what that all cost.
> The cost per liter of water extraction will also be calculated based on a pro forma Bill of Materials and estimated NRE and tooling costs. A more detailed description of this calculation is provided in the Rules and Regulations. The Affordability Index must be less than $0.02 (two cents). No prize will be awarded to a Team that does not meet that criterion.
https://assets-us-01.kc-usercontent.com/5cb25086-82d2-4c89-9...
150 gallons could be quite a lot of fresh water for a small remote village that otherwise lacks a good fresh water source. Useful for drinking and cooking, but not used for bathing or irrigation. I assume the system could be powered by a reasonably sized solar array.
On the other hand, given the cost of this setup it would probably be a lot easier and cheaper to install water filters.
We are four people living in a house & garden in france and I used 70m3 (70000 liters) last year. That would be about 190L/d or 50gal/day, 5 times less. Where do you dump so much water in the US?
With 3 adults and 4 children in my house we used 4-6HCF per month with no garden (when we moved in the irrigation system used about 12HCF per month on its own, we landscaped the yard to eliminate the need for outside watering).
So the only "magic" they are doing is also capturing the water vapor from the generators combustion. While somewhat novel in combining it all, its all off the shelf tech.
What I don't like is the lack of good hard numbers in its performance in a range of conditions as snake oil is extremely common in the water from air industry.
And, to be fair, maybe this thing makes sense after a hurricane. There's lots of "free" biomass laying around in an area of extraordinary transportation costs.
But it's obviously not a solution to the "water problem" in rural, impoverished areas. You'd need to include the price of a renewable forest or palm plantation (for coconut shells), or the huge solar array.
I imagine it doesn't look too similar to a Tatooine moisture farm.
Technical implementation is claimed to be 'adiabatic distillation' - not sure exactly what that means.
1. They’re in Hawaii. It’s a little humid there. So... yea. Dehumidifiers will collect quite a bit of water in a water abundant area.
2. The places that need clean water typically have low humidity as well. To pull water from air, there needs to be water in it.
Think of this as all those folks that claim they can run their car on water as a fuel. The thing they fail to mention was they were using a battery to split out the hydrogen from the water to use that as fuel. Which is not more efficient than just using the straight up battery.
This is a publicity stunt scam. A real shame too. That money would have been better spent on education or better water infrastructure in places of need.
So what you're saying is that they're efficient on an island miles from the the rainiest spot on the planet.
https://en.wikipedia.org/wiki/Mount_Waialeale#Climate_and_Ra...
Also, I was about to post a concern about distilled water possibly leaching nutrients from the body, but a quick google reveals the opposite may be true: https://www.nutriteam.com/distilledleach/
If you don't have drinking water, five to ten cents per day is a pretty good deal! It really doesn't matter that tap water somewhere else in the world is one cent.
Not a water expert, but here's where this reported price ranks from some googling:
Tap water in California: $.0005 / liter [1]
XPrize winner: $.02 / liter
Water truck delivery in CA: $.01 - $.05 / liter [2]
Desalination: $.05 - $.30 / liter [3]
Wholesale bottled water: $.30 / liter [4]
Walmart bottled water: $.68 / liter [5]
Tap water is awesome, btw. It's 100 times cheaper than all these options.
[1] $.002 per gallon from https://www.wsj.com/articles/my-california-water-is-an-undil...
[2] $200 for 5000 gallons to $500 for 2500 gallons for water truck delivery in California https://www.cnbc.com/2015/04/08/californias-four-year-drough...
[3] https://www.quora.com/How-much-does-a-water-desalination-pla...
[4] $1.22 per gallon from https://slate.com/business/2013/07/cost-of-bottled-water-vs-...
[5] $.02 per fl oz from https://www.walmart.com/tp/bottled-water
Not everywhere has tap water. Some places don't have an aquifer suitable for drilling a well. Other places don't even have a road network suitable for the delivery of water by truck in an economical manner (or at all).
Beyond that, drawing water from the air has benefit in that it does not negatively impact a local aquifer which might already be over-drawn. What is the additional economic benefit per liter of that? That could be subtracted from the $0.02 / liter cost if you care to look at more than just the immediate bottom line.
When I read through the article, I didn't see any links to potability test results. So there might be a purification step after this gasifier powered water generator to turn the output of this into truly potable water, so the cost won't really be below two cents per liter in the field. Purification itself is an energy-intensive endeavor, whether to create purification materials or straight use of energy in more active systems, and is why potable water is a rough order-of-magnitude proxy for energy.
Hilarious. If it was possible to recondense the evaporated water and somehow reject the heat to the air, there wouldn't be a cooling tower!
Thunderfoot is right, it's a scam: https://www.youtube.com/watch?v=e3s-xI895zc
https://cen.acs.org/environment/water/stripping-air-moisture...
See also comments on slashdot from someone claiming to be from All Power Labs, the gasifier supplier:
https://science.slashdot.org/story/18/10/22/079250/a-device-...
> In rural conditions Bio- Gasification has proved to be very productive and efficient in creating a micro-grid.
That from the FAQ here http://www.skysource.org/faq/.
https://motherboard.vice.com/en_us/article/mbddw8/artificial...
They are able to use the waste head and humidity in the exhaust to increase the amount of water extracted.
Even if that were part of the implementation, it'd likely be missing the point.
Verses plants and animals lived millennia ago, died, got compressed by huge geological forces and finally we come along and extract it and burn it.
In addition growing deciduous crops rather than annuals and good soil management practices and can help reduce or eliminate additional fertiliser requirement.
Edit: not a big Frank Herbert crowd I see.
I'm not endorsing it, just posting, i have not yet see the video.
Where did you find that? All I could find is "0.8-1.8kW/hr" for a machine with capacity with a capacity of "30gal/day". This is complete nonsense, "kW/hr" is neither energy nor power nor energy per volume of product. And if it's power, why does it vary?
I'm going to read it as 1.8kW, with a capacity of 30 US gallons (113l) per day. My dehumidifier from the hardware store consumes 0.2kW at a capacity of 10l per day. They are 15% more productive... hardly a quantum leap.
It varies, as does output, because (as the numbers mention) this all varies wildly by atmospheric temperature and humidity.
(By the way, running the numbers I'm seeing it as 62.77L/kW vs. 50L/kW, which is a 25% improvement, though at much larger scale.)
So when they write kW/hr, they mean kWh/h, which is kW, because they expect readers to be confused. But if that's the power of the machine, it shouldn't vary. Just like my car produces 70kW, not "7-70kW/hr depending on road conditions". This machine would run a max power all the time, wouldn't it?
> 25% improvement
Serves me right for trying to compute in my head. Qualitatively, it makes no difference, though: they claim a 100% improved efficiency over the competition, and they are nowhere close. The 25% difference may indeed be purely to scale; bigger machines (whether from this company or the hardware store) tend to be more efficient.
Chilling below the dew point doesn't add much, if any, performance.
(And yeah, that kW = kW-h convention hurts my brain.)
Power consumption doesn't depend on humidity. Capacity does. So if they quoted "0.8-1.8kWh/l", that would make sense (but be ridiculously low). If they quoted 1.8kW and 40-100l/d, that would make sense, too. But 30gal/d and 0.8-1.8kW implies that the machine throttles the compressor in order not to exceed the advertised capacity, which it doesn't reach under real world conditions anyway.
They are in Hawaii. An outdoor dehumidifier will work great in a water abundant area. How well do you think a dehumidifier will work in a low humidity area? The places that need water the most. It’s not making water, it’s pulling out the humidity.
This is such a scam.
I feel like I’m taking crazy pills. All these “smart” folks gave up 1.5mil and there are tech folks here nodding their heads because it’s xprize. Y’all turned off your thinking just because it’s xprize.
Say you want to help 3rd world poor and it gives you magic armor from logic apparently.
http://www.cais-soas.com/CAIS/Architecture/wind.htm
https://www.ancient-origins.net/ancient-technology/sophistic...
https://www.smithsonianmag.com/innovation/this-tower-pulls-d...
https://en.m.wikipedia.org/wiki/Air_well_(condenser)
It also seems to be able to pull a lot more water than a normal dehumifiier? "Skywater machines are ranging from Skywater 30 (up to 30 gallons of water each day) to Skywater 300 (up to 300 gallons of water a day)."
You are right we should be more skeptical though. Like how much energy does this thing use?
https://www.fastcompany.com/90253718/a-device-that-can-pull-...
https://en.m.wikipedia.org/wiki/Windcatcher
There's a similar type of building which uses temperature difference to generate condensation within a building, creating a pool of water. The name escapes me at the moment.
Vancouver Condo
https://motherboard.vice.com/en_us/article/mbddw8/artificial...
"easily deployable high-volume water generator that can be used in any climate, meeting the competition parameters of extracting a minimum of 2,000 liters of water per day from the atmosphere using 100 percent renewable energy, at a cost of no more than two cents per liter."
In fact, isn't there a big, natural dehumidifier in the center of Maui?
The ignorance in your comment is truly astounding.
"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something."
They also ask you not to snark. Could you please review https://news.ycombinator.com/newsguidelines.html and follow the rules when posting here?
Now, you might actually mean that, but it might be more useful to explicitly spell it out in that case.
You know, there are places where water falls out of the air on its own, and if you don't spoil the hell out of the landscape you can even drink it. Give it a rest, humans.
Nobody subscribes to any quaint notions anymore such as "Extracting water from air is known as rain, and it's free," or "There are already too many humans, living in too many inhospitable places, enabled by technology," or even something as simple as "Hey I can keep two contradictory ideas in my head at the same time like 'I work on technology' yet 'Technology always has a downside'?"
There's an old apocryphal saying along the lines of (please say this in the stereotyped voice of Tonto or any Native American portrayed by Hollywood): Red man build small fire, keep warm. White man build big fire, keep warm by chopping wood.
Just thought I'd throw that in, since it's roughly analogous.
The human population needs to be cut back to within a sensible ecological planetary carrying-capacity, not be further propped up by ever-more exotic tech. The cutback will happen regardless, when these technologies inevitably fail or lead to worse problems that feed back on each other. But it's still frustrating that everybody wants to just rush headlong into the brick wall instead of hitting the brakes, and that anybody who has any foresight is automatically some Luddite or old-timer. Like people fresh-out-the-womb are the smartest ones, and the unquestioning belief in tech is anything but gullibility! Give me your money then!