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Machine Condenses Drinking Water Out of Thin Air
Posted by
timothy
on Sun Nov 23, 2008 03:18 PM
from the LED-bulbs-or-klieg-light-specials? dept.
from the LED-bulbs-or-klieg-light-specials? dept.
longacre writes "A new $1,200 machine that uses the same amount of power as three light bulbs promises to condense drinkable water out of the air. On display at Wired Magazine's annual tech showcase, the WaterMill 'looks like a giant golf ball that has been chopped in half: it is about 3ft in diameter, made of white plastic, and is attached to the wall. It works by drawing air through filters to remove dust and particles, then cooling it to just below the temperature at which dew forms. The condensed water is passed through a self-sterilising chamber that uses microbe-busting UV light to eradicate any possibility of Legionnaires' disease or other infections. Finally, it is filtered and passed through a pipe to the owner's fridge or kitchen tap.'"
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Amazing! They've invented... (Score:5, Funny)
...the dehumidifier!
Re:Amazing! They've invented... (Score:5, Funny)
No, it's called a Vaporator, and it was invented by George Lucas in the 70's: http://upload.wikimedia.org/wikipedia/en/8/83/Luke-Treadwell_close_large.jpg [wikimedia.org]
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Re:Amazing! They've invented... (Score:5, Funny)
Now all we need is a droid that understands the binary language of moisture vaporators.
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Re:Amazing! They've invented... (Score:5, Funny)
Yes, but to compensate he added muppets.
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Re:Amazing! They've invented... (Score:5, Funny)
...the dehumidifier!
Don't be a smartass. It's a dehumdifier with a filter. Big difference.
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Re:Amazing! They've invented... (Score:5, Informative)
Don't forget the sanitizing UV light...
I remember instructions on how to make something like this in the scouts - it involved a sheet of plastic and some rocks.
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Re:Amazing! They've invented... (Score:5, Insightful)
My dehumidifier in my basement also uses "the electricity of about three light bulbs". The article claimed "$0.3 per litre". Lets run the numbers.
"Three light bulbs" is journalistic code for 300 watts. My electricity costs about 8 cents per kWh. $0.3 per liter implies it uses 3.75 kWh per liter. At 300 watts, it takes 12.5 hours to generate a liter of water. Or rephrased, it could fill a 2 liter soda bottle in about a day.
However, my $200 Chinese dehumidifier purchased at home depot, using the same electricity, easily fills its multigallon bucket in a day, at least during summer months. To help any NASA scientists here, multiple gallons is quite a bit more than two liters.
So, why does this greenwashing gadget cost five times as much as my dehumidifier but only produces about half the output? Surely it can't be continuously dumping 150 watts of UV sterilization light. Maybe those are metric kilowatt-hours as opposed to imperial kilowatt-hours.
The last line is also funny "reduces it from mid-afternoon when a blazing sun dries the air." The only way to dry air is rain, snow, mixing with drier air, dew, and frost. I am a firm believer in the conservation of mass, In a closed system if you evaporate a gallon at midnight I think it will still be there at noon. So, where, pray tell, does the water in the air go when the sun strikes it? Into a cave like a vampire? Outer space? Surely the "blazing sun" isn't visible from underneath a thunderstorm. I think in their inept little journalist way they are trying to say the device becomes vastly less efficient as the relative humidity falls. That would be no big deal, except that where ever there is high humidity, there is probably open water, and its usually cheaper to filter and desalinate open water than to dehumidify it. There is a certain perfection in a device that only works where you don't need it and can't work where you would otherwise need it the most.
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Seems kind of silly (Score:5, Funny)
They would get much better results using one of these things in thick, humid air rather than insisting on using thin air.
Who spends $1200 for a pimped dehumidifier... (Score:5, Funny)
Re:Who spends $1200 for a pimped dehumidifier... (Score:5, Interesting)
"public water authority"?
Ah... you must live in a large built-up area where water comes out of a big pipe provided by a municipality of some sort.
I'm on a dug well with extremely hard water and a tendency to go dry during droughts. Between the filters, UV treatment, water softener, RO filter system, pumps, cisterns, etc... there's probably $5000 for all the bits and parts of my water system. I've spent $1200 on far dumber things than drinking water. For someone with, say, a sulphur problem... $1200 would be darn cheap.
c.
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Re:Who spends $1200 for a pimped dehumidifier... (Score:5, Insightful)
> I imagine the target market is people who live off the grid...
Such people usually use a clever invention called a well.
> ...a backup in case the grid fails.
It comes with a hand crank?
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Dune (Score:5, Interesting)
I'm surprised no one has mentioned Dune or its wind traps yet.
Or that no one has mentioned another story on slashdot [slashdot.org] about extracting water from wind, even if the other one used a windmill to do so.
Re:Or Star Wars (Score:5, Funny)
I don't know - coming to slashdot and getting you're/your wrong... *sigh*
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Just Vaporware (Score:5, Funny)
Re:Just Vaporware (Score:5, Funny)
Solid liquid, eh? Exactly what phases of matter do you have over there?
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The balance may remain.. (Score:5, Interesting)
Hmm. (Score:5, Funny)
This is great! (Score:5, Funny)
Both of them.
Snake Oil (Score:5, Insightful)
It really pisses me off that even supposedly "quality" newspapers like the Guardian just reprint some PR's press releases with marginal editing rather than doing even the most basic of reasarch or even, god forbid, any thinking.
TFA answers none of the pertinent questions about this device. But reading between the lines and doing a little thinking it's pretty easy to determine this device is going to be useless as anything but a gimmik.
Firstly, how much power does it use? "Three lightbulbs" says TFA, now as far as I'm aware the lightbulb is not a standard measurement for power consumption. But let's be generous and assume they're taling about standard 60-80W bulbs, that about 200W, give or take.
How much water does it produce? The article doesn't say, their website claims "up to" 12L per day, which I'd imagine is operating under optimium conditions (i.e hot air at close to 100% humidity). That's actually not a lot of water, and i'd imagine operating in any real conditions you could halve or quater that amount.
So adding up the numbers, that's 4.8kWh of electicty to produce about 6L of water. Or 800kwh/m^3. This is a ridiculously, hideously energy intensive way to make water, even desalination, which is seen as ecologically unfreindly, uses about 3kwh/m^3, or is about 250 times more efficient.
TFA also states this device is useless below 30% humidity, which removes the last reason one might consider using it, providing water where no other method is possible.
My point in all this is that doing about 2 minutes thinking, and exactly one google search, I have been able to determine that this thing is anything but ecologically friendly, and anything but economic. The journo writing this article for the Guardian, which for those of you who don't know it prides itself on being a "green" newspaper, couldn't even be bothered to do that and reprinted some PR's words wholesale, giving people the impression that what is in fact a toy for rich consumers who want to feel good about being "green" is some kind of ecological miracle device.
It should be a source of lasting shame to any newspaper to allow their editorial content to be used by some idiot for marketing purposes, sadly it's all too common and nobody even seems to notice the extent to which PR is taking over journalism.
Incomplete information (Score:5, Insightful)
OK, it uses the same amount of power as three light bulbs when it's operating, but how long does it take to generate a liter of water? Without this, the "three light bulbs" is meaningless.
Re:Send this to the third world (Score:5, Insightful)
At 600 watt-hours per liter, you're going to be losing more energy to sweat and breathing than you could possibly get close to generating by hand.
Parent
Re:Send this to the third world (Score:5, Insightful)
Yeah, this is ONLY 200 times less efficient than desalinization.
Criminy.
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Re:Send this to the third world (Score:5, Insightful)
this should be sent to countries where drought is a problem.
If drought is a problem I suspect there isn't going to be a whole lot of humid air to extract water from. "The mill ceases to be effective below about 30 per cent relative humidity levels,"
And after cranking that thing to produce 300W (about three light bulbs, and I'm guessing it means old-style, power inefficient, ones), you're going to need more than a glass of water.
And that's before we even consider the price tag.
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Re:Send this to the third world (Score:5, Funny)
> And after cranking that thing to produce 300W (about three light bulbs, and I'm guessing
> it means old-style, power inefficient, ones), you're going to need more than a glass of
> water.
But you may sweat enough to drive the humidity up to 30% so that the thing will begin to work.
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Re:Hmmmm. The arid west (Score:5, Funny)
Fixed that for you.
Parent