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Old 16-02-2010, 19:35   #106
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"up to 70% more energy out than is put in"

If that were true then there would be quite a call for them I should say.
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Old 16-02-2010, 22:27   #107
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Calling something fuelless (a questionable word to begin with) when clearly there is fuel involved should probably be a hint. Here's one sites comments on the legitamacy:
FuellessPower.com -- Creative Power & Research
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Old 18-02-2010, 17:09   #108
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Outside the box..

It sure is nice to read all the good posts!

Thinking outside the box is hard but even harder is finding the courage to expose yourself to the judgement of the the ones inside the box.

I belive there have to be more than a thousand ideas rejected for every usable one. I also belive that the more complex problems we try to solve the bigger the need for cooperation and thinking in a group.

I have to throw out two ideas that popped up as I ws reading your posts.

First what would the effect on the solar powered boiler be if we could lower the pressure considerly in the chamber with boiling water? Im thinking about the fact that water boils at lower temperatures when the pressure is lowered.

The second thought is perhaps a bit too far out of the box but..

Given the fact that Reverse Osmosis needs high pressure and it is due to this fact the energy consumption is high I could not help thinking about where we have high pressure that is totally "free of charge".
I do not do that much diving anymore but last time I did the pressure build up as i descended was pretty impressive.
Can we bring the membrane down where we have naturally pressurised salt water?
How do we get or keep the pressure differential needed for the water to be pushed through the membrane?

Il start thinking about it but Im sure the collective approach will give some new interesting angles.

Rgds

Kristian
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Old 18-02-2010, 20:05   #109
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The second thought is perhaps a bit too far out of the box but..

Given the fact that Reverse Osmosis needs high pressure and it is due to this fact the energy consumption is high I could not help thinking about where we have high pressure that is totally "free of charge".
I do not do that much diving anymore but last time I did the pressure build up as i descended was pretty impressive.
Can we bring the membrane down where we have naturally pressurised salt water?
How do we get or keep the pressure differential needed for the water to be pushed through the membrane?

Il start thinking about it but Im sure the collective approach will give some new interesting angles.

Rgds

Kristian
That'll work. Say, an outer bladder filled with (pre cleaned) saltwater, connected to an empty inner bladder via a membrane. Drop with your anchor to a few hundred feet, then windlass up some time later.

It might be impractical as far as
-might need lots of depth, won't work at an anchorage
-the inner bladder will have to be small enough to be weighed down by an anchor
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Old 18-02-2010, 20:41   #110
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The only way I can picture a pressure differencial is if the high pressure side of the membrane collapses and the other side doesn't but I'm not sure how that would work. Pumping up to the surface would negate any gains I would think - the lift would eat up any gain from the pressure.
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Old 18-02-2010, 20:58   #111
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That'll work.
It may work. But it will not save you any energy input. Pressure is a force. You need energy. I'd guess your windlass is where the energy will be dissipated in this idea when you need to lift the huge weight used to sink the air filled chamber.

A process like the Spectra uses is about the lowest possible energy method for desal. The best area for development is in alternative energy areas.

I just bought a boat with solar panels...I'm not impressed. Too little energy for the amount of fuss and hardware.
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Old 18-02-2010, 22:04   #112
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I don't understand the objections. If you simply dropped a semi-rigid balloon made of the membrane overboard, attached to an anchor, the pressure of the surrounding seawater will force water in. Water will flow in until the pressure equillibriates. Then you haul it up. The force required to haul up (essentially mgd when full) has nothing to do with the force or pressure (force per area) required to fill the balloon with freshwater.
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Old 18-02-2010, 22:26   #113
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Back of the envelope, you'll need a very long anchor rode. A typical seawater watermaker apparently uses 800psi. You'll need about 1800ft of line for that.
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Old 19-02-2010, 00:24   #114
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Semi-rigid and very strong at the same time. Also on the way back up the pressure inside will be pretty good ... no pump neccessary. :-)
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Old 19-02-2010, 13:15   #115
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Mechanical or hydraulical advantage

Hello again!

The bladder approach is actually one also I did think of today and the fact that pressure if used directly would need to be taken at a depth that is anything but practical.

I have been thinking of if it is possible to increase the pressure say in the same way our hydraulic brakes work in our cars. It is really the same principle as we use to master our mainsheet only that the mechanical advantage is used the hydraulic way.
Perhaps is it this way possible to achive the small 1000 Psi needed at a far smaller depth of 5-10 meters..Im drawing and drawing perhaps there is a way of doing this at least from a theoretical point.

The thought of low pressure and boiling water at say 50 degrees celsius does not seem to attract much attention.
I do not know but my initial idea is that perhaps it is possible to drive a vaccum pump via a solar panel and this way keep a controlled constant low pressure inside a waterfilled chamber that is heated by the sun. The vaccum pump does of course suck water vapour out that does condensate back to water in lets say the cooler parts in the bilge.

What do you say about it possible?

Rgds

Kristian
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Old 19-02-2010, 14:29   #116
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I don't understand the objections. If you simply dropped a semi-rigid balloon made of the membrane overboard, attached to an anchor, the pressure of the surrounding seawater will force water in. Water will flow in until the pressure equillibriates. Then you haul it up. The force required to haul up (essentially mgd when full) has nothing to do with the force or pressure (force per area) required to fill the balloon with freshwater.
It's not just objections, it's physical laws. As said early in this thread it takes a certain irreducible amount of energy to separate salt from water. Lowering pressure takes energy and also raises the amount of energy it takes to boil water. For the diving bell RO idea you will spend the energy in hoisting the very heavy iron ball back to the surface. Although it is an elegant solution the universe will not allow you to dodge the energy tax.
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Old 19-02-2010, 15:15   #117
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Energy tax?

Living a rather long life in one of the places where taxation is an art I do know a lot about taxes but sure have missed ( so far) the universal energy tax!

I might be in a total missunderstanding here but separating salt from water does not need any specific energy input that has to be used like the one when separating water into H2 and O2.
The salt is in solution in the water and I belive the most obvious proof for this not having anything to do with adding or subtracting energy is that the act of pouring salt into potable water does nothing in terms of energy levels...

Next thing I do have to object to is that lowering pressure increases the energy needed to boil water. The energy to increase the temperture 1 degree celsius of a given amount of water is the same no matter of the pressure, The energy to get the Water to transform into vapour is also the same irrespective of pressure.

The difference is that you do not have to add as much energy before the boiling takes place at a lower temperature and you do not transfer that much energy to for instance the bilge when the water condensates back to water.

The point is doing the process at much lower temperatures.

The procedure of getting a low pressure situation of course costs energy but the total energy amount will be lower.

Think the opposit , pressure cooking boils your potatoes faster and cheaper. Why?

Due higher boiling temperature at higher pressure!

I have to confess that when beeing a young hotshot fighter pilot I tried to push the envelope an climbed way higher than the max allowed service ceiling.
I got a seriouse reprimand due the fact I did not wear a pressure suit and if my small positive cabin pressure had failed I might have had problems due bubbles forming in the blood. The same thing as you have a problem with when diving and ascending too fast.

The " diving bell " analogy I can see but I do not think it has to be a diving bell sort of device nor am I convinced that you have to go that deep.

Rgds

Kristian
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Old 19-02-2010, 15:41   #118
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It's not just objections, it's physical laws. As said early in this thread it takes a certain irreducible amount of energy to separate salt from water. Lowering pressure takes energy and also raises the amount of energy it takes to boil water. For the diving bell RO idea you will spend the energy in hoisting the very heavy iron ball back to the surface. Although it is an elegant solution the universe will not allow you to dodge the energy tax.
It's true that you expend energy to bring the bell back up. That energy is ~mgd with d=depth. That energy is unrelated to the energy required to fill the bell. For example, imagine instead the bell were lowered to a much shallower depth. The energy to hoist back aboard is still mgd, but d is now much smaller. The bell will still fill, even under lower pressure, it will simply take longer for the water to seep in (the water will have a Maxwellian velocity distrbution, and the high velocity tail will still drip through).
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Old 19-02-2010, 16:13   #119
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Flotation bags on the bell would lift it effortlessly
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Old 19-02-2010, 17:17   #120
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The bell is presumably empty at the surface and at atmospheric pressure. It will take a significant amount of ballast to sink it. That ballast must be lifted back to the surface after the bell is filled with fresh water. Very heavy. Compute the energy. I bet it's similar to that of a watermaker pump.
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