Perpetual Motion/Over Unity Devices

Discussion in 'General Science & Technology' started by Epitectus, Apr 19, 2000.

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  1. eddie23 information sponge Registered Senior Member

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    all machines are under unity
     
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  3. DRZion Theoretical Experimentalist Valued Senior Member

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    Okay, I got it. The volume of the water never changes, and the extra gravitational potential of the water in the tube is perfectly canceled out by a very slightly lowering sea level. No energy is created.

    However, this is a perpetual motion machine, one that will last until the ocean freezes or boils. Or, until we filter all the salt from the oceans.

    This is only one of the equations for work. There are others that rely on pressure, sunlight, wind, etc to turn a motor.

    What about a perfect carnot engine? 100% efficient and 100% reversible.
     
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  5. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    No, neither of these is correct.

    Consider the steady state with water flowing over the top of the floating tube, making power via the turbine. In this steady state the level of the sea is not falling, but is steady / constant also. Thus, you are getting energy output with no decrease in the gravitational potential of the sea.

    The carnott engine is reversible but not 100% efficient. The efficiency is (T-t)/T where T is the absolute temperature of the heat source and t is that of the colder heat sink.
     
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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    “… It is possible to levitate a rotating object with fixed magnets. The levitron is a commercial toy which exploits the effect. The spinning top can levitate delicately above a base with a careful arrangement of magnets so long as its rotation speed and height remains within certain limits. This solution is particularly clever because it only uses permanent magnets. Ceramic materials are used to prevent induced currents which would dissipate the rotational energy. …”
    From: http://www.hfml.ru.nl/levitation-possible.html
    The toy Levitron =

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    is not a violation of Earnshaw's Theorem as the magnets are spinning, not static.
    When the magnetically levitated storage system has zero energy and to get it strated spinning, some conventional ball (or roller) bearing must be used.

    Two common examples of dynamic stabalization against gravity of statically unstable conditions are an inverted broom on your finger tip or a Chinese lady with a spinning plate on top of a stick.

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    Each lady has 10 spinning plates in the air and there are at least seven ladies (only see some of the plates of the right and left most ladies). That is at least 70 plates simultaneously spinning on top of long sticks! The Chinese are amazing people with a long (more than ten times longer than the US) high level culture
     
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  8. DRZion Theoretical Experimentalist Valued Senior Member

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    Yes, a very good point. Using the proper engineering, it may be possible to make a bearing on this principle.

    There is a so called 'saddle point' in the force between two magnets.
    http://en.wikipedia.org/wiki/Saddle_point
    The levitron spins the saddle point and thus creates a permenant local minimum.

    Yes, this machine is driven by gravitation at the expense of heat. This machine harnesses pure heat without the need for temperature differences. It seems someone has beaten me to my perpetual motion machine.

    Gravitation is not the source of energy, it is merely the driving force. There is no need for any temperature difference.

    In the above example, is there a temperature difference? No. Is gravitational potential constant? Yes. Is this 100% efficient? I would say so.

    Epic.


    As a disclaimer, I will admit that it is only the illusion of perpetual motion. Sooner or later, the system will either freeze due to heat death of the universe, or boil due to an expanding sun.
     
  9. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    No that is not the correct answer either. If it were, it would work in a lake too. (that is hint.)
    Fountain can work in isothermal water, but probably is not as the deep ocean water is cold ~4 C. Thus if you want after this cold drinking water has turned the turbine generator it can be the heat sink for a low efficiency Ocean Thermal Power system too! (They are all low efficiency as the available temperature difference bwteen surface and deep water is small, 30C at best. So if surface were 300K the efficiency would be (300 - 270)/300 = 0.1 or 10% in but is nowhere on Earth's oceans is it that high.

    I have not thought much about the efficiency - but it is extremely low as you will see when you understand why it works.

    BTW look at post 44 again - I have added an amazing second photo why you were posting.
     
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  10. DRZion Theoretical Experimentalist Valued Senior Member

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    Are you sure this would work? It seems that there must be a considerable pressure difference to drive reverse osmosis. Because fresh water is lighter than salt water, the pressure at the bottom of the osmotic tube is lowered. This lowered pressure continues the osmotic process, while freshwater escapes out the top of the tube, where it can drive a turbine. Is this correct???

    The same would happen in living cells, but they are closed. So, instead of letting water out they burst. In this situation, the fresh water escapes out the top. This is the basic principle behind the fresh/saltwater fountain. However, the thermodynamics and energetics of it are still tricking me..

    The point is- potential energy never changes for the ocean water. You said this yourself, and I can confirm it. BUT, work is still done? This would mean energy is created.
    As work is being done, the ocean would have to cool to offset the energy consumed through work. Potential energy never changes, but work goes on forever? This can't be right. Perhaps the physics of this fountain are more subtle than you first thought.
     
    Last edited: Jul 30, 2009
  11. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    yes it will work if the tube is long enough (assuming the ocean is deep enough). This observation of yours can be your second hint - think long and hard about that and how it must change.

    For late comers who also want to try to solve a good puzzle (as why sea water fountain is NOT and PM or OU device) see blue text at:

    http://www.sciforums.com/showpost.php?p=2326306&postcount=32
     
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  12. DRZion Theoretical Experimentalist Valued Senior Member

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    It does seem like it should. However if it does, it is definitely PM

    and maybe OU. . . but that's ridiculous.

    The water will keep rising in the tube until pressure at the membrane is at equilibrium from both sides. Since fresh water is less dense, the fresh water column will have to be taller than the salt water column at equilibrium. If the tube is cut so that equilibrium cannot be achieved, water will overflow and continue flowing towards the unreachable equilibrium.

    For this to not be OU the ocean water has to somehow get cooled. But, I have no idea how or where. This cooling must somehow be related to pressure (or height in other words).

    You can probably make this machine much more efficient using something other than seawater. . .

    Can we talk about the thermodynamics of it now????
     
    Last edited: Jul 31, 2009
  13. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    That is a nice concise explanation of how it works. (Better than mine!)

    No, the entire ocean can stay with exactly the temperature and distribution of temperature it has at the start. - Let's assume the tube walls are a good thermal conductor and with the very slow osmotic flow the water inside the tube at any depth is at the same temperature as the water outside. Or assume the entire ocean is at 70F and always remains at 70F. (Not true but if it were the fresh water still overflows the top, driving the turbine as falls back to sea level.)

    Lets give some time for others to figure out why it is neither PM nor OU. (The answer is not that sun dies and oceans freeze - it is more fundamental than that.) Think some more about my second hint especially.
     
  14. DRZion Theoretical Experimentalist Valued Senior Member

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    1,046
    Thank you.


    Then what you are proposing either is OU, or it does not work. Follow the logic.

    1. Temperature remains the same (you say). This means that thermal energy is constant.
    2. You are driving a turbine and thus doing work. This creates heat energy.
    3. This heat is over unity. It comes from no where.

    Surely, this isn't what you mean.


    So, the water has to cool if this isn't to break any laws of thermodynamics. Where does this water cool? And, better yet, how is the heat transformed into gravitational potential energy?

    The only idea I have is this -
    When you open a scuba diving pressure tank, gas escapes. When this gas escapes it expands, and for some reason it is cold even though the tank is at room temperature. I think this is due to the ideal gas law.

    So, I think that as the water passes through the membrane it expands (it must, that is how density is lowered). Due to this expansion it cools just like the gas escaping from the scuba tank. This colder water of course quickly equalizes with the surroundings. Nevertheless the ocean is cooled in proportion to the change in pressure, and it is the change in pressure that elevates the water column. The pressure is related to height of the tube, and overall it is the isentropic expansion of fresh water that produces the potential energy. The potential energy is then released as the water falls back into the ocean. The kinetic energy of the falling water is dissipated as heat back in the ocean, or is used to drive a turbine to produce work.

    Remember, if there is no pressure difference at the membrane the system is at equilibrium. In this case no work can be done and there is no cooling.



    PS I realize it is kind of silly to think that a liquid will cool upon expansion. Or is it?? Not at all. If energy remains constant and a liquid expands, it must cool down.
     
    Last edited: Jul 31, 2009
  15. Steve100 O͓͍̯̬̯̙͈̟̥̳̩͒̆̿ͬ̑̀̓̿͋ͬ ̙̳ͅ ̫̪̳͔O Valued Senior Member

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    It gets slowed to a stop by the turbine (didn't really pay much attention to the question to be honest).
     
  16. DRZion Theoretical Experimentalist Valued Senior Member

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    The water gets slowed down by the turbine only because it is doing work. This doesn't change sea levels and the machine can continue running.
    The membrane is doing work too. The two cancel out. It works. If there would be no turbine, all the energy would be put back into the ocean as kinetic energy. With the turbine, some of the heat is lost as work and that is how the ocean cools.


    To be concise and rational-

    A pipe filled with freshwater, submerged into the sea, will have a growing pressure differential with its outsides.
    At one point this pressure will exceed the pressure required for reverse osmosis.
    Below this depth, an osmotic membrane should continuosly suck in water and pour it out the top.

    Its really hard to beat.


    As the water goes through the membrane, it will expand. And I do think it will in fact expand, and not just
    lose density.

    "Changes in hydrogen bond strength for water are interpreted in terms of electron delocalization involving
    cations, anions, and water. A perturbation molecular orbital (PMO) model gives a good account of the
    limiting slope of apparent water density. Model values for solution densities at low concentrations compare
    favorably with experimental results. Changes in the structural equilibrium for liquid water caused by the
    presence of ions will be reflected in changes in the free energy of solution for even the lowest concentration
    of ions."
    This is from a paper about salt water.

    The energetics work out I assume. Energy is not created, it is only transformed. This is something I refer to
    as 'Ambient Heat Conversion'. It seems to violate the second law, but I can assure you it does not. I have
    done A LOT of thinking about it over the past 2 years. It is essentially a perfect carnot engine. Reversible,
    100% efficient. No entropy done in the cycle (however, plenty of potential for entropy outside the cycle).
    No entropy done in the cycle means it will work in a closed system without violating any laws.
     
    Last edited: Aug 1, 2009
  17. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    To DRZion:

    I have tried to get you thinking more productively with a couple of hints. Your on the wrong track with thermodyanic thermal considerations although it is probably true that the H20 from great depth does expand and thus does work and thus does cool as it moves to the surface. However the total heat content of the ocean does not change as when it falls on top of all the other water in the ocean that water is compressed and heated in exact compensation. Let me try to prove this to you or at least make it very plausible:

    Image a square vertical tube with 1 cm^2 cross section a little more than 2.6m tall filled with 260 gm of water. I conceptually (only) divide it into 2600 thin horizontal layers, each 1mm tall, with names, A1 thru A100, B1 thru B100 …Z1 thru Z100, which is the bottom layer. There is also a top layer of air / water vapor called A0, which has the same mass as all the other layers. (The top of the tube is rigidly closed so that the actual air pressure does enter into our discussion.) Thus on top of layer z100, there are 2600 layers with total weight of 260 gm.

    Now tiny valves exist at bottom of layer Z100 and at the top of layer A0 which allow me to first take “one layer’s worth” or 0.1gm of water from Z100 and then add it back into the air layer A0 via a syringe. When I take water, I let the 260gm/ cm^2 pressure on top of layer Z100 push the plunger of the syringe – I.e. that water, like the water passing thru the osmotic membrane, does work, expands and cools as still within the syringe, it comes to the zero pressure at the top of layer A0.

    Until that “syringe water” has been injected to become the new layer A1, the air layer, A0 essentially doubles it volume and also cools. “Essentially” as the bottom layer has only 2599.9gm/cm^2 pressure on it and also ever so slightly expands also. Note also that each of the layers remaining in the tube falls essentially 1mm So the total work done (falling water column and push on the syringe) is just what is needed to lift the syringe water back to the top and inject it. I.e. as should be obvious when the original conditions are restored, so is the gravitational potential. New layer A1 is cooler as you noted but you failed to note (in the ocean case) that all the other layers have been compressed (For example, the new A2 was the old A1.) – are under 0.1gm/cm^2 more pressure than they had before 0.1gm of “syringe water" was removed. This compression both heats them and the colder new A1 is slightly more dense than the original A1 so it has fallen in the gravity field just enough to compensate for the “essentially” I mentioned earlier. When thermal conduction within the tube has restored all layers to the same temperature it is the originally temperature and everything is exactly as it was.

    Summary:
    No net work has been done and no temperature change has occurred. The conditions are exactly restored. The ocean case however does do net work and everything is not just as it was. (That change you need to think about - what is different? It was your hint 2 or 3, recall?)

    In the ocean case, the wind and ocean currents due to the non-uniform solar heating (gulf stream etc.) and some surprisingly due to fish and jelly fish swimming do this restoration of prior thermal conditions. They partially (or totally?) undo the the change the system is making.

    Now for your new (third?) hint: This work producing system is NOT some thermal engine. Stop trying to understand it that way. It is much more like a system getting energy from coal to do work. Where did the coal get its energy from? This system is using the same type of stored energy as the coal energy system is. It would eventually stop as it is making that energy less available to itself*, much like burning coal is making stored energy less available. It would eventually stop, except for the sun, the wind and the swimming fish. I.e. it is not a PM machine. Perhaps with this hint you will understand to that it is very far from an OU device also. – It has terrible efficiency as the sun, wind and swimming fish do exist!

    -------------------
    *But ironically it is making the energy MORE available to longer tubes and other systems which can tap into this same stored energy, if it were not for those swimming fish and wind.
     
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  18. DRZion Theoretical Experimentalist Valued Senior Member

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    Yup, in the ocean the water is injected above the A0 layer. This potential energy has to come from somewhere. It could either be chemical, mechanical, or gravitational potential energy. I think it is in fact the stored mechanical energy.

    Not totally, because work has been extracted from the system.

    Coal got some of its energy from the sun, but it also got some of it's energy from the earth. Its kind of a composite material. What kind of stored energy do you mean? Its certainly not chemical, like coal.



    I did some extra investigating-

    http://true-random.com/homepage/projects/diffusion_machine/
    http://www.lhup.edu/~dsimanek/museum/osmosis.htm
     
  19. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Your first ref may be correct but it is not a clear presentation and I only skimmed it. The second is wrong badly wrong as he ignored the density difference between sea and fresh water (after many had pointed that out he said it was only 2.5% (not very important) It will work, but requires a tube much longer than he even dreamed of. He also says 20 atmosphere differential to drive reverse osmosis, Perhaps that is correct so I will use it and fact that column ~30 feet deep of fresh water has one atmosphere at the bottom.

    If the top of the tube is tiny amount above the sea surface and filled with fresh water then 30 feet down it out side in the sea the pressure is 1.025Atm. for a pressure difference of 0.025Atm. According to him we need to had a differential of 20Atm. So 30(20/ 0.025) = 24,000 foot tube is required to develop the 20Atm pressure differential needed for reverse osmosis. Roughly 4.5 miles long I don't know if the deepest ocean trenches are that deep or not, but the system is so far from economical it really does not matter.

    ---------------
    I will not have internet access tomorrow and no one else is actively interested so will tell part of the answer now. There is a huge amount of energy stored in strong brine. I.e. it took the sunshine millions of years on the entire ocean to evaporate the volume of the ocean many times over making million os year of rain, which fell on the rocks and carried the various dissolvable minerals to the sea, making it more salty as time past.

    As an aside, long before man knew about fusion energy they knew the sun was releasing a lot every year. Where it came from was a problem. One way to estimate how long it had been shining was to measure the salt content of major rivers and their flow to estimate how long rain had been falling to make the current salinity of the oceans. (Much more than the 6000 year of the Bible was the not very popular answer.)

    a salt flat (no water now) is a huge store of solar energy - Mankind has yet to lean how to economically use it. Oil is sometimes found in salt domes not full of salt anymore due to ground water flows, I think, If they were filled with salt, instead of oil the stored energy would be greater! It is sort of like nuclear energy - for long time man did not know how to get access to this stored energy. That is the current state of the chemically stored energy in concentrated brine or a salt flat.

    If we ignore the continuing action of the sun, especially its indirect action called wind, then as the sea fountain runs the top layers of the ocean become fresh and the bottom more salty (assume no wind or fish mixing.) that is the center of gravity of the ocean is being lowered even thought the level of the ocean is not changing (much). This is where most of the energy would come from, I think, in the no wind or fish case. Likewise in this no mixing case, any given length tube will cease to function as the salt concentration at the bottom increases. The more concentrated is the brine the more the higher the pressure difference required is to get reverse osmosis flow.

    In reverse osmosis you are not using the energy stored in the brine, but adding to it. To tap that energy you need to dilute (undo the suns concentration) the brine. I'll quite now but just mention that with string fresh water pan and strong brine pan you can make a salt powered motor. A huge fortunate awaits anyone who can discover how to make a practical, economical salt powered motor. The energy stored in salt of the earth is I am nearly sure at least an order of magnitude than stored in oil, possibly several orders of magnitude greater! We just to not know how to economically tap into it.
     
  20. DRZion Theoretical Experimentalist Valued Senior Member

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    :bugeye:

    Wow. That is quite the extended and far-reaching analysis. It is true, in a closed system the fresh water would form a layer on top of the salt water, until the salt water was too concentrated to undergo osmosis.
    [edit]: not necessarily however, because brine is hygroscopic. Adding water molecules to the system won't necessarily create a layer, rather the water molecules will get drawn into the brine. I still think that such a system might possibly work when it is closed off with no external energy.


    The diffusion machine at the bottom of the first link seems to avoid this problem of water layering... It also takes into account the density differences of the gas produced by gravity.
    http://true-random.com/homepage/proj...usion_machine/
    I have actually tried building a perpetual motion machine something like it this summer

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    For some reason, most people don't like the idea that Kinetic energy can be constant over long periods of time. In our everyday life, we observe that kinetic energy halts to a stop. That is why people oppose perpetual motion machines.
    A system with constant energy, what difference is it whether the energy is kinetic, thermal, electric, chemical? Its still energy!
    If you look in the sky, there is some kind of perpetual motion out there! The planets keep orbiting the sun, so much kinetic energy that it is hard to imagine.
     
    Last edited: Aug 3, 2009
  21. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Yes: "brine is hygroscopic. Adding water molecules to the system won't necessarily create a layer, rather the water molecules will get drawn into the brine." But "drawn into" is not the best way to look at this - tends to be misleading.

    In the sea with a fresh water layer on top, there is a difusion gradient. Not many Na+ or Cl- ions going donward as they are far fewer there than in the sea water below. Eventually, if not for the reverse osmotic fountain, diffusion will mix and to make the concetraions NEARLY equal, but the action of gravity will keep the bottom always slightly more salty. BTW, Einstein got his Nobel Prize for something very much like this AND the photo electric effect.

    He modeled the vertical distribution of uniform size Brownian motion spheres. After a few years of hard work, some French scientists comnfimed that distribution - Einstein's model assumed that atoms were real - at least half of scientistis had strong doubts that was true but almost all accepted atoms as facts after Einstein's "atoms dependent" model was confirmed.
    It was sort of a "tipping point" for the atomic theory.

    As H2O has both H are on the same side of the O (105 degree angle between) it is intrinsically an electric dipole. (This makes them hook up so cold water especially is really a mix of nH20 chains and other 3D structures, which are thermally breaking up and reforming. ( n is a temperature dependent set of small integers) When you add an ion these H20 diploes tend to cluster around it so the effective mass of the typically nH2O can be slightly increased. Thus to throw such a cluster, perhaps often only ClHHO- (note I put both HH quasi protons, next to the Cl-) up thru the water /air interface, is harder to do. Hence salt water has an higher boiling point.

    Thus once the Cl- is in with lots of nH2O s the idea of "holding" is OK, but there is not much if any "drawing down" of either ion.
     
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  22. DRZion Theoretical Experimentalist Valued Senior Member

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    I realized this is necessary in order to keep conservation of energy intact in this scenario that I have mentioned earlier in this thread.

    If the whole chamber is of uniform temperature and pressure, then any water condensing at the top will have gained gravitational potential energy. There is absolutely no source for this energy, and so it seems like it has been created.

    However if you assume that there is a pressure difference, the difference in energy can be explained through condensation/evaporation. At lower pressures, less energy is released due to condensation/evaporation. So, a little bit more energy is picked up at the bottom of the chamber than is deposited at the top; this energy difference cancels out the gravitational potential. Energy is not created, it only changes forms.

    In a closed system, a box three feet cubed, thermal energy will be constant for ever. No one doubts that. However, kinetic energy cannot be constant? What makes thermal energy different and special?
     
    Last edited: Aug 5, 2009
  23. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    No. There are several sources of the energy when there is net flow from the bottom to the top of H2O molecules. One source, which gets the process started, is the energy stored in the salt when the sun evaporated the water from it to make salt crystals. (I am not sure, but suspect that as the salt disolves it too will cool so part of the energy driving the process is the heat of binding being removed from the salt.)

    You need to clearly distinguish between the initial conditions when this chemical stored energy is being used and the final steady state conditions when the vertical flow of H2O molecules is zero. Initially the hydroscopic properties of the salt will remove H2O from the moist water vapor at the top. Then the water in the tank at the bottom will evaporate more H2O molecules and cool, so in addition to the chemical binding energy of the salt crystal, thermal energy is being removed at the bottom.

    Eventually the colder bottom water will have the rate of H2O molecules leaving it equal to the rate water vapor molecules are entering the water in the bottom tank - I.e. the level of the water in the bottom tank will cease to drop. That was a gravitational energy loss, which also helps drive the system. Likewise, the rate at which H2O molecules are escaping the "grasp" of the salt solution in the tray at the top will equal the rate at which the H2O molecules in the slight less dense (due to gravity) vapor (moist air) at the top are being captured by the salt water solution in the top tray. I.e. eventually at every station from the water surface at bottom to the surface of the salt water in the tray at the top, the net flow of H2O molecules is zero.

    All the mass of H2O that was lifted against gravity is a gain of mgh in its potential energy, but the thermal energy in the water (and even the moist air above it) is reduced to achieve part of this gravitational gain. The remaining part comes from the solar energy stored in the dry salt crystal you initially charged the system with.

    If after equilibrium is established you were to open the well insulated system and restore the initial conditions for a second run to the steady state, you will need to heat the salt solution with more energy than the gravitation energy it produced in the first cycle to get the dry salt crystals back again. You will also need o re-warm the bottom water etc.

    As you should expect - this system requires net input of thermal energy to close the cycle as you are converting thermal energy into gain of gravitational energy, not very efficiently at that.

    It is really not differ than burning some wood in a boiler to produce work. The sun supplied the energy to grow the tree. In this case, if you get your salt from a salt deposit, the sun was the source of the energy for the first cycle. You will burn natural gas, or nuclear fuel, to reproduce the starting conditions for the second and subsequent cycles.

    Unfortunately, there is no free (energy) lunch. Most of it, including nuclear, came from some sun or gravitational collapse and mankind is helping nature degrade it into heat.
     
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