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Desalination via ice

by Godspanther
Tags: desalination
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Godspanther
#1
Feb14-14, 05:55 PM
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Would it work/be practical to build a desalination system in a place that has high mountains near coastal areas? In places like the Atlas mountains of Africa and the Andes in Chile which are near coasts & deserts yet high enough to be snowcapped it may be ideal. Water could be brought to the top of the mountain via a close valved siphon system relying partially on solar powered pumps to move water from sealed tank to sealed tank each incrementally higher up the mountain. Once above the snowline the water would be allowed to freeze over, separating fresh from brine. The ice would be mechanically removed and sent down the mountain via chutes. The seperation tank would then be sealed and a valve opened allowing the brine to flow out into a closed system similar to that which raised the water up the mountain. The resulting vacuum would assist the solar powered inflow system.
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SteamKing
#2
Feb14-14, 07:33 PM
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That's a lot of heavy lifting to do for a drink of water. It would probably be cheaper to tow an iceberg from Antarctica north.

With solar energy, you can boil seawater at sea level and condense the vapor into fresh water, or make electric energy to drive a flash distillation or reverse osmosis plant.

http://en.wikipedia.org/wiki/Desalination

Water is rather a heavy fluid, and the less pumping and lifting you do, the cheaper it will be.
Godspanther
#3
Feb14-14, 08:09 PM
P: 20
Getting enough water pumped to complete the siphon effect would take some time and energy. Once the siphon was established however gravity and solar power would do all the work. After filling the tank one would close off the siphon valves & let the water freeze. Then the tank would have to be unsealed and the ice collected. Then comes the tricky part. The tanks would have to be resealed and enough air pumped out to maintain the siphon once the intake/outflow valves were reopened.

256bits
#4
Feb14-14, 08:31 PM
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Desalination via ice

That is an interesting idea, but to work a siphon one needs gravity and another feature that you have neglected - atmospheric pressure. The atmospheric presure will only push a column of water up to a height of 30 feet (10m ). At the top of the column the pressure is zero so no more "sucking" effect of a siphon can be had.
the siphon effect as you describe will work with only mountains that are only 30 feet high. So back to pumping....
SteamKing
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Feb14-14, 08:32 PM
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Siphons work on pressure differences. At sea level, the maximum differences in siphon levels are approximately 10 meters, and the higher up the mountain you go, the smaller the difference in level the siphon can have. All in all, a rather Rube Goldberg approach to desalinating water:

http://en.wikipedia.org/wiki/Rube_Goldberg

Some actual Rube Goldberg contraptions:

http://coolmaterial.com/roundup/rube-goldberg-machines/


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