Pressure Harvesting - from ocean depths

Discussion in 'General Science & Technology' started by Quantum Quack, Mar 8, 2020.

  1. Xelasnave.1947 Valued Senior Member

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    8,502
    Hi Quantum Q
    Why don't you work on harvesting the pressure at sea level?
    It's enough to hold up a 30 inch pile of mercury.
    All that energy waiting to be harvested.
    I feel if you can appreciate the difficulty in harvesting pressure at sea level you will understand the difficulty with your idea.
    It's like the hydro idea of just pumping the water back up to the dam..sure that can be done but think of the energy to pump that water up... without doing the sums I think you would find you would be losing huge amounts of energy..although using renewable energy to pump the water up could be a way to store the alternative energy...but even then the system would be very inefficient. Think of how much energy to lift only a ton of water and relatively how little energy from that ton running a water wheel.
    Good luck in your search for energy solutions.
    Alex
     
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  3. Quantum Quack Life's a tease... Valued Senior Member

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    It is in the clever use of natural forces that may make the difference.
    Example:
    The Rance Tidal Power station in France....is a classic hydro system and to be honest not very clever IMO ( basic tidal Hydro) but it is effective in delivery of cost effective electricity and is very competitive with coal fired or nuclear.
    The local environmental problems though are not the best and ideal tidal/volume locations are not that easy to find. So it is limited in it's application. Be that as it may the Rance Power station is a successful project IMO.
    The same applies to typical hydro electric stations, where ideal locations are hard to find and their dependency on rivers running normally, filling the dam.

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    Pumped Hydro is a great idea when using off peak energy that would be wasted other wise but the initial infrastructure is extremely expensive.
    New designs in Hydro turbines have and will continue to improve the output of hydro systems.

    Basically we are getting more clever in how we approach these issues which is a great thing of course.
     
    Last edited: Mar 10, 2020
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  5. Quantum Quack Life's a tease... Valued Senior Member

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    another example yet to be fully employed IMO is the Capillary action of water. Which apparently utilizes the surface tension you refer to. (?)

    but low density energy sources are yet to be seriously considered.
     
    Last edited: Mar 10, 2020
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  7. Xelasnave.1947 Valued Senior Member

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    There was a tidal "power station" on the Hawksberry River just North of Sydney.

    I don't know if they turned a paddle wheel or employed turbines but it existed so long ago it was only a memory of old locals when I heard about it fifty years ago.

    As to pumping up to a dam I have been thinking of putting in my own system.

    Up North I only have solar, wind and deep cycle batteries or various petrol generators.

    I don't have my figures but the idea was to get around the high cost of batteries.

    The idea is that in the sunny times solar panels pump up water to a dam and when you need power from there run the water back to the bottom dam where you have a water wheel.

    I can't recall but it would be cheaper short term to go batteries...I worked out I could store in effect 10 kwts but it would take ages to get that much water up top...
    Not a problem as it would only be used after a couple days of cloud or if you got caught out with no petrol for the Genny. The idea becomes interesting when factoring in battery life as against pump life and panel life. However what I have found is even on overcast days the panels put out enough to keep the batteries topped up...and I am getting four more.

    I would like about $25000 of batteries so you can see why I think about the pump up idea. I even have a design for a home made battery using lead flashing and Epsom salts.

    I think about this stuff all the time..like generating H and O via electrolisis and running an appropriate motor...and all these ideas start from wondering how not to waste sunlight after the batteries are charged.
    Next thing to use the "spare" sunlight is to have it heat the hot water system via solar panels (electric not things with water)....I have that unit on order actually (unit and more panels $3000 to $4000 ..I can't remember as there are other items as well) .it will also use spare power from the Genny...you run the Genny to charge at say 400 watts but the Genny puts out 2000...with this unit wasted lower will heat water.
    Off grid you spend a lot of time thinking about both generation and storage of electricity.
    Alex
     
  8. Quantum Quack Life's a tease... Valued Senior Member

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    23,328
    Do you have a flowing river/stream near by?
     
  9. Xelasnave.1947 Valued Senior Member

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    8,502
    I don't think I mentioned surface tension the mercury is held up by air pressure...
    Alex
     
  10. Xelasnave.1947 Valued Senior Member

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    8,502
    Yes but for hydro you need a big drop or a decent flow..the creeks and rivers with these places won't cut it. My biggest asset is a 60 mt hill behind the dam. There is no dam up top yet but I have room.
    Alex
     
  11. Q-reeus Banned Valued Senior Member

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    4,695
    QQ:
    Any ideal (dissipationless) closed path taken by an object in a Newtonian g = -Gr/r^3 gravitational field neither gains or loses net energy. That's because the g-field is defined as
    g = -∇φ, where φ is the Newtonian gravitational potential, itself given by
    φ = -G/r. So we have a completely conservative, spherically symmetric central force field, for which
    ∇ x -∇φ = 0. Zero curl. The latter is a fundamental mathematical fact and excludes any possibility of net gain or loss of energy over a closed path.
    If your siphon principle worked it would have to violate that indisputable mathematical relation.

    As others have pointed out, just stick say a plastic drinking straw in a glass of water. Obviously there is no siphon fountain to be had.
    Mathematically and physically impossible.
    QQ - it's always best to concede early on rather than doggedly dig in to the point of making it almost psychologically impossible to then retract.
    I note some members talked about 'doing the math' but none has been done here till now. Which isn't much but is adequate.
     
  12. Quantum Quack Life's a tease... Valued Senior Member

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    23,328
    I appreciate your concerns and help.
    Just be sure we are talking about the same thing...
    What do you mean by siphon principle and how does that relate to the issue of compressing air upon decending .....
    The idea of a siphon is, as you suggested absurd. I never suggested such a thing. I never suggested free energy either.
    So it takes multiple pages just to clear up the confusion i seem to have created.
     
  13. Q-reeus Banned Valued Senior Member

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    4,695
    What you in effect proposed in opening post - water gushing up out of a pipe spanning from at or above the surface to deep down in the depths. Bladders, pistons, hauled up/down using ropes, chains etc. cannot evade the fundamental limitations inherent in a completely conservative gravitational field. Disappointing but if it did work how long ago do you think that would have been realized and seized on?
     
  14. Quantum Quack Life's a tease... Valued Senior Member

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    23,328
    Have you explored the use of portable hydro systems designed for campers etc?
     
  15. Quantum Quack Life's a tease... Valued Senior Member

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    How on earth did you get that interpretation from the OP?
    If you don't mind explaining it....so i can do better next time i discuss alterative energy systems.
     
  16. Xelasnave.1947 Valued Senior Member

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    8,502
    No.
    I am not aware of such.
    Alex
     
  17. Q-reeus Banned Valued Senior Member

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    4,695
    It's really implied there. All that pressure 'for free' at the bottom - yet it lifts the level in a partially submerged pipe by 0 cm. The expected behavior of a conservative system. And btw I was somewhat hasty in #128 and neglected to include M - the central gravitating mass - in the 1st & 3rd line expressions there.

    Just remember gravity is the source of pressure, and gravity is a conservative field. No getting around that. Step back and get a bird's eye view of the total system. The only non-conservative forces in play are owing to dissipation. Hence lossy.
     
  18. Quantum Quack Life's a tease... Valued Senior Member

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    23,328
  19. Quantum Quack Life's a tease... Valued Senior Member

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    are you sure you are talking about the OP of this thread?
    no mention of free...
    no mention of siphoning...
    so I have no idea what you are on about...
    please explain...
     
  20. Q-reeus Banned Valued Senior Member

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    4,695
    Let's cut to the chase QQ. Seven pages.....
    Do you or do you not now accept your notion of energy harvesting of a hydrostatic pressure gradient is impossible? It's all covered in #128 with slight amendment as per #134.
     
  21. Quantum Quack Life's a tease... Valued Senior Member

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    23,328
    well it's like this... if you can make such silly claims about the thread OP with out explaining it then what's the point of answering your post. You'll only misinterpret it like you have already proved you are capable of doing...
    Until you acknowledge your confusion you'll just have to read the thread were it refers to pressurizing air as a VVSS descends and then allows air pressure to be exported to the surface...

    Do you deny that sinking a variable volume vessel can pressurize air that can be exported to the surface?
     
  22. Quantum Quack Life's a tease... Valued Senior Member

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    at the moment I am attempting to work out what 10 cubic meters of 350000 kPa air pressure provides in Joules...
    but my math skills are hopeless.
     
  23. Q-reeus Banned Valued Senior Member

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    4,695
    Of course not. But to what useful end? You've already had many inputs from others pointing out why that achieves nothing except to waste otherwise useful input energy. Owing to any number of dissipative processes - including the inherent losses whenever a finite-time compression-expansion cycle is done on a gas. Which can never be purely isothermal or purely adiabatic.

    But at rock bottom, what I wrote in #128/#134 is the inescapable fundamental prohibition against realizing your idea(s). Time to admit that, yes?
     

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