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Is friction an efficient heat source?

  1. Aug 22, 2014 #1
    Hi all, first post on PF!
    I was just wondering if a motor that is specifically designed to generate the most friction possible would be useful for heating purposes. If it's just wishful thinking, feel free to say so and explain why.
  2. jcsd
  3. Aug 22, 2014 #2


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    Staff: Mentor

    Welcome to the PF.

    I would think that wear and tear on the friction surfaces would be an issue. Also getting the heat to whatever you want to heat up. What are your thoughts so far about those issues?
  4. Aug 22, 2014 #3


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    It would likely wear itself out quickly ... not a good idea
  5. Aug 22, 2014 #4
    The object I want to make is a self heating blanket (no electricity either-probably using an alternate energy source). Ideally the heat source would all be inside the blanket layers and the motor well shielded from the soft layers through a material that's durable and resists wear and tear yet is still porous to heat. Well, I need to do more materials research...
    Thanks for your insight though!
    Last edited: Aug 22, 2014
  6. Aug 22, 2014 #5


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    The practical problem would be spreading the heat from a local area to where you want it.

    Friction can easily generate very high local temperatures, e.g. melting synthetic fiber ropes such as climbing ropes by rubbing against metal, or even melting metals like aluminum and titanium in metal-to-metal friction.
  7. Aug 22, 2014 #6


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    How would you spin the motor without electricity?
  8. Aug 22, 2014 #7


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    Staff: Mentor

    Friction is 100% efficient at producing heat, but it isn't necessarily an easy or practical thing to use, but there are ways to do it:

    You could, for example, get a large pot of water or a more viscous liquid (honey?) and use a big beater to stir it. That would eliminate potential wear issues from normal kinetic friction.
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