Friction heat generator

  1. Friction is phenomenon we try to avoid but it may be useful.
    Does anyone know about existing friction heat generators and what method they use ?
    Seemingly, solid matter does not suit as it pulverizes as well as wears out the generator parts. Probably, remains gas compression. There cannot be a liquid whose stirring can cause very high heat emission ?
    Last edited by a moderator: Mar 26, 2013
  2. jcsd
  3. russ_watters

    Staff: Mentor

    Yes, stirring a liquid produces heat. I did a project at a chocolate factory where the chocolate was stirred with 100kW mixers and the vats had to be water-cooled to keep from burning the chocolate.

    I'm not sure how this information could be useful though...
  4. I'm not sure why you would want a friction heat generator, you'd need to take power or fuel of some description, turn it into mechanical energy and then turn the energy into heat, and probably a lot of noise. Going power or fuel to heat direct is going to be more efficent and easier.
  5. AlephZero

    AlephZero 7,248
    Science Advisor
    Homework Helper

    That's a bit more impressive than wimpy "mechanical equivalent of heat" lab experiments like :biggrin:
  6. AlephZero

    AlephZero 7,248
    Science Advisor
    Homework Helper

    Friction heat generators do have some uses - for example

  7. I was thinking that wind or wave energy can be transformed directly to heat (where we need just the heat). Electricity generators utilising wind or wave energy are inevitably losing some of it on its transformations.
    Only the power you would need to add to the system were for the controls and to drive a circulation pump.
    One would need to find a most "efficient solution" having the highest heat generation while stirring, so to say, at the lowest viscosity.
    Last edited: Mar 24, 2013
  8. russ_watters

    Staff: Mentor

    1. Wind and wave energy is already directly converted to heat if we don't harness it to generate electricity.
    2. All friction based energy conversions are 100% efficient, so they are all the same as far as the output goes. The only difference is the complexity of the device, which no matter what, will be more complex (expensive) than a heating element.

    You're not looking for an overunity heating device, are you...?
  9. I was not wrongly thinking there could be found a substance in the process in qwestion in which output energy exceeded input one, but it looks like this.
  10. russ_watters

    Staff: Mentor

    You can never escape conservation of energy.
  11. Thank you for your answers ! Will now know how "Joule" and "Calorie" relation has been established, but most importantly for me - that any matter can be stirred with the same final result.
    Last edited: Mar 25, 2013
  12. jim hardy

    jim hardy 5,460
    Science Advisor
    Gold Member
    2014 Award

    A mechanical engineer will tell you that an ordinary pump slightly heats the fluid being pumped.
    That's why big pumps always have something to assure minimum flow, so they won't overheat.

    In our power plant we heat the reactor system to operating temperature (547°F) in a reasonable number of hours by simply running the main pumps. Ours total about 18,000 horsepower.

    Paddlewheel tests is I believe how the early scientists established the relation between work and heat.
    I'm an old guy who still uses 778 ft-lbs per BTU and 3412.7 BTU/KWH...

    old jim
  13. But, finally, to put an end to the thread, why would not it work : the conversion of the wind energy directly into heat ?
  14. russ_watters

    Staff: Mentor

    All wind energy not converted to electricity is directly converted to heat.
  15. jim hardy

    jim hardy 5,460
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    2014 Award

    A friend of mine wanted to do just that.
    His application was for cattle ranches in Western US where winters are cold and windy.
    The ponds and streams all freeze over in the bitter cold.
    His intent was to place a small windmill at watering troughs out in the pastures.
    They would drive a paddlewheel to warm the water, perhaps melting a spot in the ice big enough for the cattle to get a drink.

    I don't think he ever finished his idea.

    should work fine.
    But it'll have to have that certain "pizazz" if you want consumers to buy it.
    Maybe if you emblazon "914 Turbo" on the side.....

    old jim
  16. Melting a spot on a frozen pond in this way, Jim is, on my view, like scooping water with a sieve !
  17. NascentOxygen

    Staff: Mentor

    Didn't an early scientist measure the temperature increase after water had descended a high waterfall, to allow him to compare the increase in heat content with the loss of gravitational potential energy?
  18. And what heat, approximately, is generated when 1 kg of water falls from 1 m of height ?
  19. russ_watters

    Staff: Mentor

    I think it was Joule who did it...

    Do you know how to calculate the potential energy of an object...?
  20. NUCENG

    NUCENG 916
    Science Advisor

    Paddlewheelers weren't much good during winter due to ice. Running a paddlewheel adds a mechanical device capable of wear, blockage, and failure. An electric generator and heater powered from a windmill is more costly and also adds another energy conversion and inefficiency, but might be more reliable and efficient. A motorized pump is probably also more efficient in stirring up the water in a tank than a paddlewheel. Quantifying the differences in mechanical, and thermal, and conversion efficiencies would be interesting, but practtical design also includes cost, maintenance, and reliability.
  21. How about the running an air compressor, and somehow extracting the heat from the compressed air.
    Doubling the pressure of air also concentrates the heat.
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