FLYWHEEL Energy Storage Systems

Discussion in 'Propulsion' started by brian eiland, Apr 21, 2010.

  1. brian eiland
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    brian eiland Senior Member

    I didn't claim it would be the perfect solution to our energy needs. Its just one small piece of the large problem...how do we STORE energy. You are correct it is not an energy producer, but neither is a chemical battery. Both of these devices must be RECHARGED. And in many cases you will find a big deteriotion in chemical batteries just left on their own...in fact most will discharge, some rather quickly. (and then how do you get them to restart?).

    It's not necessarily a flaw that they are a moving body. The space station is a moving body that must continue to rotate to maintain its artifical gravity. But its doing so in the vacuum of space and thus requires VERY little energy input to continue this rotation. Our flywheel operating in a total vacuum coulkd continue to spin much longer than most of the best batteries of today can hold their full charge.
     
  2. CDK
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    CDK retired engineer

    The term "crude" I used for the toy cars system.
    It is very inefficient because of the way it is produced: you have to put the toy down immediately, within a few seconds all energy is lost by friction.

    The advanced version with a vacuum chamber, carbon fiber etc. conserves the energy much better of course, but is expensive to produce, needs maintenance and has losses in the transmission but when storing and retrieving energy. In my opinion a direct driven electric motor/generator and large capacitor are cheaper, lighter and more efficient.

    Almost every IC engine has a flywheel and exerts forces when the vehicle changes direction, but the construction is sturdy enough. And it doesn't spin at 60 000 rpm.
     
  3. Luckless
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    Luckless Senior Member

    What space station currently rotates to maintain an artificial gravity environment?

    Flywheels are ill suited to mobile applications, as any force exerted on them depletes some of the energy stored in them. They're fine if you want to travel in a straight line, but haven't you ever seen the grade school science class experiment where you hold a modified bike wheel or similar with both hands by handles that let the wheel turn freely. Someone spins the wheel up, and you try to turn the wheel. You get a surprising level of resistance.

    As for chemical storage, well not all 'batteries' and methods of man made chemical storage discharge quickly. In fact many don't even carry a charge and are non-direct electrical systems, but we just don't see them that often.

    There are variants on the basic "Hydrogen Fuel Cell" concept, using man made chemicals as an 'energy storage' system. They're stored in tanks which can be sealed and isolated, and will retain their entire 'charge' for 1000+ years. Of course the drawback in a combustion or reaction system, as opposed to what we traditionally think of as a 'battery', because they require extra hardware to convert the stored energy to usable. They do however, usually have a far greater ratio of energy per-tank space than normal chemical batteries. That is part of the reason why massive ships are fueled by combustion based systems and not banks of batteries.
     
  4. daiquiri
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    daiquiri Engineering and Design

    Well, that's true for a simple flywheel, but if you put them in a cage connsisting of two freely-rotating concentric rings, or gimbals, with perpendicular axis of rotation, you get a gyroscope, which doesn't have such problems. In fact airplanes do have gyros for inertial navigation.
    I believe that's what Brian Eiland was referring to...
     
  5. mark775

    mark775 Guest

  6. Luckless
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    Luckless Senior Member

    Gimbals dampen the loss, but they don't eliminate it. Take a properly designed fuel container, then it doesn't care what way you move it, X amount will still provide X energy at the end of the day.
     
  7. CDK
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    CDK retired engineer

    Re posts 19, 20, 21:

    It was supposed to be a mechanical energy storing device.
    To be able to add energy or use it, the flywheel would have to be rigidly mounted and looses energy with every movement.

    Unless someone has a viable idea about a mechanical connection to a gimbal mounted wheel.......
     
  8. mark775

    mark775 Guest

    If it were only allowed to spin in a horizontal plane and possibly gimbal around a longitudinal axis and was used for energy storage as well as stabilization, I think we have something. I think that as long as it doesn't gimbal in one dimension, it can have a mechanical connection. Am I missing something?
     
  9. capt vimes
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    capt vimes Senior Member

    i fully agree with CDK on the effectiveness of a flywheel vs capacitors... the losses will be a great deal less with the capacitors then with the flywheel...

    besides - i do not see the advantages on a ship...
    for cars now it is an rather easy way to store braking energy for later acceleration...
    but on a vessel one has to burn diesel, suck electricity from batteries to spin up the drive and use it for what?
    like the capacitors (although the latest generations get better and better and some are capeable of storing energy even longer than modern batteries) this flywheels have a great loss of energy over time... one has to consume it rather soon... and still there is the question for what?

    if one finds a way to transfer the motion energy of the vessel from the waves (like all the rolling, yawing etc motions) to a flywheel, it would be some sort of alternative 'free' energy and a big win imo... otherwise it is nothing more but a energy transformation with big, big losses and not worth the hassel...

    for cars it is different since a part of the braking energy is captured instead of wasted completely by beeing transformed to 100% heat...
     
  10. Mr. Know-It-All
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    Mr. Know-It-All Junior Member

    It is possible to use magnetic fields to store/use energy from a flywheel. Electric motors work that way.

     
  11. FAST FRED
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    FAST FRED Senior Member

    The big advantage of the flywheel car is the ability of the individual wheel mounted regenerative breaking can input a huge percentage of the energy created quickly.

    A property not possible with batteries.

    Also the possibility of a pad supplied energy input.

    Drive over it , stop in the right spot and no connection is required to re power the flywheel.

    FF
     
  12. vendeep
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    vendeep New Member

    Its all about energy storage...

    Flywheel systems are in par with capacitors. They simply store energy.
    As few of the posts pointed out, these systems may not be appropriate for mobile applications. However, they can be useful in appropriate setting.

    Say, the Energy stored from the grid during off peak hours can be used to smooth out the demand spikes during the day. In this case, the system only needs to store energy for a few hrs/days, and with magnetic bearings and high vacuum the system can maintain efficiencies >95%. Same concept could be applied with renewable energy systems (solar, wind, geothermal, so on). When the renewable source is not available, the flywheel system can be used to supply power...

    Beacon recently completed a station in NY, and in the process of testing for full scale usage. Check it out. http://www.electroiq.com/index/blog...orage-trends/post987_5597105304657064739.html I think its just a matter of time when these systems will be used commercially.
     
    Last edited: Dec 28, 2010
  13. FAST FRED
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    FAST FRED Senior Member

    "Say, the Energy stored from the grid during off peak hours can be used to smooth out the demand spikes during the day."

    At last , were back in COAL powered cars,that are used as backup for peak air cond demand.

    FF
     
  14. RonL
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    RonL Junior Member

    I'm not sure I have ever seen a thought process or expeirments that work from the other end of our energy needs.
    Almost all storage is made too expensive or too dangerous because of the belief that we must have the total need stored in one charge or one container.

    What would be the slowest acceptable speed that anyone would live with, if the energy had to be used at the same rate of production ? the same as taking advantage of the wind.

    Using 10KW as an example, smaller boats would travel faster, what would be the largest boat, at the least acceptable speed that this amount of power would satisify ?

    Energy density is not the most important thing.

    If energy needed was almost free, how slow would anyone be willing to travel ?? anyone have thoughts along this line ?

    Ron
     

  15. Submarine Tom

    Submarine Tom Previous Member

    Thanks for asking RonL.

    I'd be willing to travel as slow as 1 1/2 knots but I'd have to be able to take my entire home with me.

    OR, in a sail boat I'd be happy with 5 knots... hey, wait a minute, that's already been done on solar energy alone. That's how a sailboat's powered right? By the sun making wind.

    -Tom
     
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