🚀 go-pugleaf

Posted & Mailed

Thank you Robert
Most of what you say is correct - just a few points need comment
BUT you probably didn't see the original post - or maybe I was too subtle 
I only discussed this ultradeep water scenario to get the attention of some
'hard' scientists.

The important bit is in the PS...

> PS of course you could put the membrane only 500 or 1000 ft down and Pump the
> water up.
> Not quite so fancy (I love physics that looks like magic) But it would use
> only around 30% of the energy of conventional reverse osmosis plants (no need
> to compress the flow-by water) not to mention no containment pressure vessel
> and hence the membranes don't have to be so compact to be cramed into pressure
> vessels so they would be cheaper etc etc etc.

According to your calcs that '500 to 1000 ft' should be 350 metres (1200 ft approx)
But I think you may have over estimated the salt concentration at 35g/litre -
I thought it was more like 25g/litre

Anyway - put the membrane down there and you simply have to pump the water up
- just as if you had a fresh water well that deep.

Robert Virtue wrote:

> The system would work, if there is sufficient circulation (this is the energy input
> bit) at depth to remove bypass water (the bit left behind after RO). In other words
> the energy input is current flow which is ultimately solar and tidal. 

No No No - the increased density of the bypass water would cause its own
circulation - ultimately the energy imput to a perpetual system is the solar
and tidal remixing of the salt but there is no direct imput at the membrane

> It is not
> perpetual motion.  

Why do people keep mentioning this silly thing - everything is perpetual
motion and nothing is - it's simply an invalid concept - it valid only to a
vague fuzzy whoopieeee version of reality.

> However, given the maintenance requirements to prevent fouling of
> the membrane (11 km below surface kind of rules out snorkel, fins and a scrubbing
> brush) and the difficulty of initial installation, the scheme is not exactly
> practical.  Maybe you could use robots :-).  You also better hope the whole lot
> doesn't get wiped out by a turbidity current after an earthquake.  Don't forget the
> initial energy and financial input to manufacture the system.

If I WAS to design such a project I would not use conventional technology at
all - I would be looking at things like burying the deep imlet in a
semi-permeable rock that acts as the osmotic barrier (is this possible?) or
self-renewing biological membranes.  The pipe-line itself could be built for a
tiny fraction of conventional cost using electroaccretion...
 
Does anyone know if electroaccreated material (it's very much like sea shell)
can be made semi-permiable???
 
> Ultimately if your going to harness solar energy or tidal forces there are much more
> efficient (less inefficient?) ways of doing it.

Yep! - WET wings - the ultimate in wave energy - coming soon to a newsgroup
near you...

> Back to work
That WAS work - to the degree that you were thinking new thoughts

> Robert Virtue
> 
> By the way OSMOSIS is  what you get when you turn off the power at an RO plant :-)

And I always thought it was the work of the Radical Molar Equality Party
pressure group ;)

John Cook

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