Slashdot Mirror
Creating Water from Thin Air
Iphtashu Fitz writes "In order to provide the U.S. Military with water in places like Iraq, the Defense Advanced Research Projects Agency gave millions of dollars in research funding to companies like LexCarb and Sciperio to try to extract water from the air. Amazingly, a company that DARPA didn't fund, Aqua Sciences, beat them all to the punch by developing a machine that can extract up to 600 gallons of water a day from thin air even in locations like arid deserts. The 20 foot machine does this without using or producing toxic materials or byproducts. The CEO of Aqua Sciences declined to elaborate on how the machine works, but said it is based on the natural process by which salt absorbs water."
I recall reading an article about ancient rock mounds, where the rocks were loosely lumped with plenty of space in between. Air filtered through and encountered the cool rock faces of the interior of the mound. Water condensed on the interior rock faces and trickled out the bottom. I'll see if I can find a link.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Sounds like they probably use a hydroscopic compound such as calcium chloride and then you some type of ion replacement to recover the water (precipitate calcium metal and some other non-soluable salt, such as Fe(III)Cl.
Cool! Amazing Toys.
Here we are, as promised. About a third of the way down the page. Ignore the Reichian weirdness, the wells were built near the ancient Byzantine city of Feodosiya. There were 13 large conical tumuli of stones, each about 10,000 feet square and 30-40 feet tall, on hilltops. Russian engineer Friedrich Zibold calculated they would each produce more than 500 gallons daily. These theories have been disputed by some archeologists (who don't seem to like it when engineers discover cool archeological stuff and make up theories about it) but the mounds do all have numerous terra-cotta pipes around the base, presumeably to collect the run off
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
this is coming from an australian company, seeing as australia is both the most arid continent and largest desert island in the world.
You shall know him by his Sig
It's pretty much a reusable desiccant - and in the best case (probably using reverse osmosis) the energy cost will be about an order of magnitude worse than desalinization plants. It even says in the article that the cost is 30 cents a gallon (which is probably highly optimistic and certainly cannot be verified without full disclosure from the company). At 30 cents a gallon (or perhaps 3 dollars a gallon when you're operating it in field conditions) you could forget about serving any sort of civilian market, and even for military use it would be quite expensive.
The DARPA funded companies did not have the same motivation as the other one. It is in their best interest to keep making slow progress and asking for more money everytime they have a little breakthrough. The successful company had no such money train. It was in their best interest to actually PRODUCE RESULTS in order to patent, market, and sell the technolohy. Funny how that works huh?
Finkployd
You recall incorrectly. Windtraps.
-Peter
The water will be consumed by soldiers who will breathe it out, sweat it out and urinate it out. The breath, sweat and urine will all evaporate the water back into the air. This is essentially a closed system with some losses which are overcome by adding energy into they system.
IANAL, but I play one on
1) Water from plants is always drinkable. I'm talking about water from the root system, not some stagnant water you could slurp out of a recess between branches. The easiest way is to take a large trash bag, grab a cluster of branches and put the bag around them (make sure the open end of the trash bag is tightly sealed to prevent air from going into the enclosed bunch). It forces the tree to "sweat" water from its root system. After about 24 hours you can slit the bottom of the bag and drain it into a nalgene bottle. You can only do one group of branches per 24 hour period, so you need to use different trees to gather water. I tried it out when I was in Eastern Oregon (which, for all intents and purposes, is an inland desert) and averaged about 1 liter of water per 24 hours. I had 6 trash bags that I normally have in my hiking ruck, so I could feasibly harvest 6 liters per day if I was SOL somewhere.
2) A cluster of birch trees usually means there's water underground.
3) Any multi-celled berry (ie: raspberry) is edible.
Anyway, I thought it was pretty cool shit, and informative. :)
I like big butts and I cannot lie.
That wouldn't work, sandtrout absorbs all water on the surface, that's why Fremen reservoirs were in rock caves, and why all their water came from the air. By the way, Arrakis wasn't all that dry, as Liet-Kynes remarks.
Yeap, I love Dune. My dream is to get a stillsuit and move to the desert (ok, some huge worms roaming around would be cool, too).
A solar still produces water in the desert and uses no external energy source other than sunlight (there is plent of that in the desert)
Did you read the article at all? The company was awarded the contract. The machine works. DARPA just never funded their research.
It sounds more like they created a substance that uses intermolecular forces to have a high attraction to water (like salt or any other desiccant). The secret is making it so that under a specific condition these water molecules can be released again (heat, pressure, etc). Then possibly combined it with standard evaporation methods through compression and cooling (standard dehumidifier).
So in all they probably just found, or dynamically adjust, the 'sweet spot' between the two methods to produce the most amount of water with the least power.
Two things.
1: Water does have a shelf life, which is why if you're storing it for long periods you have to add stabilizers.
2: The bottles can leach into the water over time, and some plastic bottles are set up so that they will begin to bio-degrade in a couple years, hence the date stamped on each bottle when you buy them.
My mom says I'm cool.
Pheonix has an average daily humidity of about 55% IIRC
You don't RC, it's more like 3%. Its 20% right now and they're predicting rain, which they usually don't get a whole lot of.
The humidity is so low they don't use standard air conditioners there; they have "swamp coolers" which work by evaporating a stream of water. Very cheap and efficient where there's practically no humidity at all. At 50% humidity one wouldn't work.
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
It's only an issue if water is permanently removed from the environment, which it generally won't be. Water was in the air and in a few hours, it is back again.
This is actually much better than trucking in water from afar or pulling it out of deep wells. In that case, you are altering the environment. Water not previously in the environment is being added.
Yeah, that's why it's more likely to be the result of "wind setdown" and the resulting bore when the wind failed. The water being pushed back to expose a path would have been a reasonably common event. If you were a local, you'd know it would be a dangerous path to use, but if you were desperate to escape it might have seemed worth the risk.
There's some interesting theories, including this one, here. http://www.europhysicsnews.com/full/33/article6.pd f#search=%22part%20the%20seas%20moses%20science%22
"I've got more toys than Teruhisa Kitahara."
All roads, of course, led to Trantor (Rome). I don't think that Asimov hid his borrowing from history - note that any author generally freely borrows from history, past or present (reality). Borrowing so heavily from another author's works, on the other hand, is another matter IMHO.
That might have been the cover story, but I seem to remember at some point it being revealed to be a puppeteer machination.
I have here a copy of a book entitled "The Inventions of Daedalus", which reprints the column of the same name by David E. H. Jones from New Scientist magazine. This column would propose unusual inventions, generally based upon sound scientific principles and seeming entirely reasonable except for their total absurdity. Previous proposals include a scheme for slaughter-free meat production by harvesting reptile tails which then regenerate; a weapon called "Shattergas" causing sudden and catastrophic corrosion of militarily important metals and plastics; and an addictive birth control pill which the user would never forget to take.
Anyway, it includes a column dated May 25, 1978 entitled "The Desert Waterer" in which "Daedalus" proposes just such a device, whereby moisture is collected from the air by means of a hygroscopic liquid. The water can then be extruded through a semi-permeable membrane if the liquid is under sufficient pressure. This can be accomplished simply by placing the liquid in a tall column; moisture enters at the top and the hydrostatic pressure at the bottom allows recovery. Daedalus then considers some convenient liquids for the purpose. Sulfuric acid is readily available in industrial quantities but would need a column 2400 meters high, which is somewhat awkward. Invert sugar syrup has a higher molecular weight and would require a column merely 720 meters high, as well as being nontoxic, and even edible in case of an emergency. Best of all, he says, is a product called "Carbowax", for which a column of only 50 meters would suffice.
The firm in charge of this present project has a suspiciously similar name, so perhaps they have just created a better Carbowax.
Daedalus, in the book, cites a number of cases where an invention from the column has become the subject of serious research. So this is just one more example...