ozcad wrote:Newfie said:Unless you know of some other technology.
Nope. I got nuffin else. Sorry.
My main thrust was about the doubtful wisdom of burning FF's followed by multiple energy transformations to get a bit of mechanical work done when you could directly harness the mechanical energy of waves, which, I hear, are often close to water. Near-zero GHG emissions to run.
The high water pressure is a worry, the head of water required to raise water over intermediate terrain to get it inland is directly added to the filter pressure differential.
We could use one pump for filtering, the LOW pressure output of which is fed into a secondary delivery pump. All wave-powered.
This would reduce the danger of having extremely high pressures throughout a large scale delivery network. All of the above is still required if FF's are used to power things anyway.
Suggestions invited.
There is a low tech energy solution not unlike your suggestion. Simply place a pipeline out to sea going down the continental slope until the bottom has the needed pressure gradient. Then place a reverse osmosis filter system on the deep intake end and flush the pipeline by pumping water out of the shore end and dumping the water into the sea. As the sea water in the pipe is removed you create a partial vacuum that will draw fresh water through the filters on the deep end. After a few days of pumping the water in the pipe will be pure fresh water. You then back flush the system for a half hour or so with fresh water to clear the filters on the deep end of accumulated gunk. After that you pump fresh water out at the shore and every week or so back flush to clear the filters. every few months you shut valves and replace the filters on the deep end being careful not to contaminate the fresh water already in the pipeline. For this system you don't need a super powerful pump, by removing water from the inside of the pipeline you create a pressure gradient that causes water to seep in through the filters at the deep end.