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A Clever New Approach To Desalination
jbeaupre writes "The Economist reports on progress by a company called Saltworks on using saline gradients to do the heavy lifting of desalination. In essence, Saltworks uses solar energy or waste heat to concentrate sea water. They then use the ionic gradient between the concentrated brine and two sea-water streams to pull ions from from a 3rd sea-water stream. It appears to work with entropy by trading the reduced entropy of the desalinated water against the increased entropy of 'mixing' the brine and the other sea-water streams. The article only discusses Na and Cl, but even just removing these ions is a step in the right direction."
If they need entropy why don't they just use /dev/random rather than wasting valuable solar energy?
This could create greater access to fresh water. That could reduce the likelihood of a water based we're-all-going-to-die situation. What if we have to find some other end of the world catastrophe to whine about?
Thinking about desalination makes me remember that episode of "The Voyage the Mimi" in which they used the process to make drinking water:
http://video.google.com/videoplay?docid=-524069894840499801# (A/V's not synced)
Freedom is drinking a beer in the park when you're supposed to be at work.
Except for that last absurdly inaccurate statement (made me chuckle), this sounds really good. Not the fastest way to desalinate, so it would take an awful lot of these to meet demand (or one really gigantic one), but still this could be at least a partial solution.
Caveat Utilitor
anyone else think this looks suspiciously like: http://en.wikipedia.org/wiki/Perpetual_motion
Desalinization is most likely the wave of the future, given the rise in sea levels and melting ice. We might as well put the extra water to good use, rather than just let our low-lying lands drown.
...what all flora has been doing forever.
But it was kinda funny, right above the article title was a statement on how to filter firehose.
Restore the madness of youth's lechery
OK between this and the General Fusion guys http://www.generalfusion.com/ Canada has got water and energy completely licked. http://www.saltworkstech.com/ OK actually I'm still trying to run the numbers on the both of them (and waiting for some peer reviewed publications.)
1) use the sun to create sea salt.
2) sell it
3) buy fresh water.
Some drink at the fountain of knowledge. Others just gargle.
Comment removed based on user account deletion
Does the word "nigger" actually personally offend you? Or do you avoid it and frown on its use because you feel like you're supposed to? Real question, and maybe as an AC you can give a truly honest answer.
The word doesn't offend me. I avoid it because I realize that others may be offended by it, and I do not understand the complex history of its word. Besides, there are plenty of other ways to refer to other human beings besides the color of their skin. Consider their first and last name, for instance.
The key piece of the work is an ion bridge. This has to permit the travel of one kind of ion but not the other, i.e. Na+ or Cl-. Looks like this material could be expensive. It might plug up need to be periodically replaced. How expensive these are? How non toxic these are? What is needed to manufacture them? These are the questions we need to ask.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
Thank you for that link to General Confusion. Made my day. Check out the freshman T-rex with his lava lamp and the sordid diatripe:
http://www.generalfusion.com/fossil_fuel_crisis.php
The planet was covered with dense clouds and the atmosphere contained a high concentration of carbon dioxide, producing tropical conditions north of the 45th parallel. For example, many dinosaur fossils were excavated in Alberta, Canada. As the earth's crust cooled down, volcanic activity reduced.
Riddle of Burgess Shale's fossil-rich deposits solved
The site, close to the B.C.-Alberta border, is considered crucial to understanding the so-called Cambrian "explosion" of life - a time when the future Canadian land mass was drifting in tropical climes close to the Earth's equator.
In my historical atlas, the equator is considerably south of the 45th latitude. The dinosaur fossils in Alberta are equatorial in origin. But hey, if you can't get that right, no obstacle to solving the fusion problem. Like it's not a hard problem or anything. The typical Alberta fat cat oilman probably doesn't believe in plate tectonics to begin with. Just a bunch of mud we turn into money. Now they're all excited about version 2: just a bunch of water we turn into money.
BTW, the Royal Tyrrell Museum in the Alberta badlands is pretty kick-ass if you're into bones.
It does not, because thankfully I'm not one.
Sounds like Forward Osmosis.
This it by no means a new technology or method.
"The process begins by spraying seawater into a shallow, black-bottomed pond, where it absorbs heat from the atmosphere." ...
"All the rest of the energy has come free, via the air, from the sun."
I don't think solar radiation works the way The Economist thinks it does.
"The air" is cooling it off, not heating it. For that, you need something like a black-bottomed pond to absorb heat from solar radiation..
And we could freeze a bunch of it and ship it to the poles.
I prefer rogues to imbeciles because they sometimes take a rest.
From the way they describe it, it sounds a lot like Maxwell's Demon. Since there is energy going into the system, however, it's clearly not that.
Who cares?
Did you know conventional desal plants produce lots of concentrated brine? If they could stripe the ionic difference out of this wase product, they would.
Reverse osmosis has a special filter.
OK here we have something called a 'Bridge' - same thing.
Forward / Reverse - depends which side - blowing or sucking.
You can flow water over such filters, BUT miserable output - you need pressure and emergy - lots of it to get water.
I think you can make a salt/brine battery from the ponds - but back of envelope calculations would reveal minimal energy contribution at end of day.
Isn't this a large-scale demonstration of the same principle used in home reverse-osmosis systems? It sure sounds familiar.
... is if it would be possible to combine solar-thermal power generation with desalination.
Build Fresnel-lens solar concentrators and stick them near a source of seawater. Boil the water using the sunlight, and use it as the working fluid in an ordinary steam-turbine-type power generator. But instead of recycling the same water once the steam recondenses, realize that you've just made a giant distiller: drink the water and use "new" seawater.
So I read the thing.
The process concentrates sea water to brine by an evaporation method. So why waste this low grade stream it is still has high in moisture content. There is already a condenser in this system. I'm thinking this can somehow boost output of clean water.
Does the word "nigger" actually personally offend you? Or do you avoid it and frown on its use because you feel like you're supposed to? Real question, and maybe as an AC you can give a truly honest answer.
The word doesn't offend me. I avoid it because I realize that others may be offended by it, and I do not understand the complex history of its word. Besides, there are plenty of other ways to refer to other human beings besides the color of their skin. Consider their first and last name, for instance.
It's also,important to remember that it does not have to denote a race or skin color. I tend to evaluate people based on their actions, and I have learned that the epithet could be applied to many of the people that post flamebait as AC. You are what you do, this is your hood, and your question is just some more mostly worthless graffiti. I say mostly worthless because it DOES show YOUR true color, no matter your race.
Too bad salt water has a higher boiling point... it's easier to use a closed loop with pure water.
The winter in Poland is already plenty cold enough...
:-P
Cheers,
"What in the name of Fats Waller is that?"
"A four-foot prune."
This idea of ion bridges has been around a long time. The application here is basically misrepresented. All it is doing is replacing a small amount of commercial electric power with solar-generated potentials. But the process isn't feasible when run on commercial power, even if the power is free, so replacing the commercial power with solar (the germ of the "idea" here) is just disguising the dead horse. Reminds me of the algae gambit: the solar constant crossed by photosynthesis is dismal, so no biofuel (corn ethanol, biodiesel, etc) can possibly be effective, but if you photosynthesize with algae, the very irony of pond scum making something useful is enough to make you (briefly) forget physical limits. Notional fantasies vs genuine engineering.
Just like it takes energy to desalinate water the opposite is also true: energy can be produced from salinating water.
See http://en.wikipedia.org/wiki/Osmotic_power
What this system does is to concentrate seawater by evaporation and then use the salinity gradient between that concentrated brine and normal seawater to produce energy. This energy is then used to desalinate another stream of seawater. In principle, there is no reason to use this energy specifically for desalination. It could also be fed to the grid.
Is there anything inherently more efficient in using energy derived from osmotic power for desalination compared to using electricity from any other source? The answer to this question will probably determine whether this process can have any real benefits over the alternatives.
One potential advantage is that this system uses only ion flows and not electron flows. AFAIU, using electricity would have resulted in unwanted electrolysis byproducts which this system elegantly avoids. There is also no need for any power conversion circuits, wires, etc.
Stop worrying about the risks of nuclear power and start worrying about the risks of not using nuclear power.
Ice displaces water, which will just make the sea level even higher, you bloody fool !
I've long wondered about a few things when it comes to desalination, desert areas etc.
If it's cheap to make water with this process and remove the salt - would it be a good idea to create a huge bunch of these machines in desert-areas, pumping desalinated water into fields to promote vegetation to grow, fighting back the desert? I would think this wouldn't require the water to be further cleaned, after removing the salts..
Am I completely off my rockers, or is it a maybe-sort-of workable idea?
"Rune Kristian Viken" - http://www.nwo.no - arca
The source of the energy to evaporate the water is irrelevant, solar works just as well for either process. Assuming an essentially unlimited supply of seawater for cooling to the distillation step, I don't see how they can make enough concentrated brine to filter the seawater more cheaply.
I think the answer is cost. Near where I live a company makes table salt. They have acres and acres of these shallow ponds, and when the tide comes in they open the valves, filling up the ponds. Then they close the valves and wait for a few days for it all to dry into this muddy slush that gets scooped up by heavy machinery and, I hope, purified.
Aside from the land itself the entire operation is so cheap it's almost free. Sure, you could somehow trap that water vapor and cool it enough to change it back to a liquid, but the increase in cost would be enormous on a percentage basis.
Well... Then we'll stack it up on the continents!
Semi-automatic amateur armchair Australian philosopher; conjecture ready at any moment...
i'm curious about your sig - what does it mean? I can't quite figure it out...
(1.21 gigawatts) / (88 miles per hour) = 30 757 874 newtons
Not an expert, but from what I've seen (on shows like World's Toughest Fixes, etc.), modern steam turbines are very sensitive to impurities. Even the size of water droplets matters. Running seawater vapor through one would probably not work without a redesign.