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B Is it possible to harvest energy from fluid buoyancy?

  1. May 30, 2017 #1
    So I've noticed my little sister's helium balloons floating at the ceiling. Made me wonder if someone could create a device that could harvest energy from this buoyancy. What if I tied a very long rope to a huge balloon filled with helium, and rolled the other end of the rope to a gear attached to a generator of sort. As the balloon goes up, the rope would rotate the gear, generating electricity. Would that work? more importantly, would it be efficient to make such a device?

    English isn't my first language, so I apologize in advance!
  2. jcsd
  3. May 30, 2017 #2
    But once the balloon is all the way up, then it stops.
  4. May 30, 2017 #3
    What if we made a device that automatically deflates the balloon when it reaches the top? The balloon drops to the ground, tie the rope again.
  5. May 30, 2017 #4


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    We do not discuss perpetual motion here. Not even to tell you why it cannot work.
  6. May 30, 2017 #5
    So, either you are compressing the helium at the top (which takes energy) to reuse it, or you are just letting the helium escape and filling it with new helium at the bottom. Well, you quickly run out of helium that way, and it costs too much to harvest new helium.
  7. May 30, 2017 #6


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    Staff: Mentor


    @Ahmad Esber -- Please follow the links in the quote below from the PF list of Banned Topics. They should help you understand why your idea will not work. Thread is closed.

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