🚀 go-pugleaf

John Cook wrote:
> 
> Hi - I posted this 10 days ago - zip response - does this mean it's True?

Well, yes and no.  If you can achieve steady state with it, it's
working off of some combination of solar, geothermal, and tidal
energy.  IOW, no violation of thermodynamics as we know it.
...
> > Imagine a long tube reaching from the surface to the bottom of the japan
> > trench.  It's bottom end is a reverse osmosis filter unit.  It is filled with
> > fresh water.
...
> > Such a device will sit there for'ever' emiting a fountain of fresh water.
> >
> > Kewl?
> >
> > I think the energy comes from slightly lowering the potential energy of the
> > salt in the ocean. Am I right about this?

Yes, you're correct.  Potential energy of the salt is the key
to understanding this.

> >
> > John Cook

As others have pointed out, the water near the inlet of the membrane
will become more and more salty; but with a current (perhaps induced
by your own, very efficient propellers) you could keep it going at
positive energy output for many, many years -- theoretically, until
the entire ocean at that depth reached a chemical potential that 
would prevent further flow.  At any point, the work you'll have
extracted from this system will never be more than the collective
loss of potential energy of the Na+ and Cl- ions that have moved 
downward in the sea.

It's exactly as if you'd found a pile of salt on a hill, put it on
a cart, and rolled it down the hill to generate energy.  No funny
business going on at all.

Of course, the ocean with its currents will actually help you, by
lifting the heavy brine back up and mixing it with the fresh water
that flows down from your fountain.  As long as your system does
not perturb these currents too much, you could reach steady state.
You would then be extracting energy from the currents, in effect.
(Off hand, I'd say you're better off doing it directly by sticking
a propeller into the current, but who knows...  at any rate, the
engineering of your device would be darn tricky.)

> John & Rhea Cook
> 'Words don't grow on trees, you know' Me
> 
> A Pox on Fascist software...