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Seebeck Devices

Discussion in 'Energy, Environment, and Policy' started by Johncarberry, Nov 20, 2014.

  1. Johncarberry

    Johncarberry New Member

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    A new technology in Seebeck Devices enabled by a recently developed insight into quantum size effects means we can expect new devices in the future to be able to harvest as much as 40% of waste heat as electricity. Given that the waste heat component of an engine is about 70%, this means new automotive engineering approaches could allow a very small internal combustion engine to generate enough electricity to charge film capacitors and batteries to double or triple MPG while providing electric car like acceleration with lighter weight, lower cost and far longer range. Is this something the Tesla community would find interesting? Is Tesla the most likely candidate to introduce such a breakthrough?
     
  2. Robert.Boston

    Robert.Boston Model S VIN P01536

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    Umm, do you have any links or more info? Extraordinary claims require extraordinary proof.

    Leaving that aside for a moment, I don't see how this applies to anything Tesla Motors is doing. It already has extremely high-efficiency motors with far less waste heat than is created by internal combustion engines. Assuming this technology could/will/does work, it would seem to fit better in vehicles with both an engine and a battery, e.g. the Chevy Volt, Toyota Prius, Ford C-Max Energi, etc.
     
  3. RichardC

    RichardC Cdn Sig & Solar Supporter

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    This would indeed be revolutionary (in the sense that it would seem to overturn basic laws of thermodynamics, which have to date been quite robust).
     
  4. Saghost

    Saghost Active Member

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    If such a device worked, you wouldn't want/need an ICE to begin with. You could burn the fuel more cleanly in a simple burner, and then use all of the heat to drive the electric converter - with greater efficiency than virtually every generator in existence, and almost no moving parts.

    However, I haven't seen anything to suggest such a device is possible, let alone buildable soon.
    Walter
     
  5. green1

    green1 Active Member

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    That's awfully harsh, the claim is recovering 40% of waste heat as electricity, and that ICE loses 70% of it's energy as heat instead of the desired motion. That would mean that you'd end up with an ICE with less waste heat, and more electricity. If the claims posted here are taken at face value, you'd extract an extra 28% of the energy from the fossil fuels (though you'd loose some in storage and motor losses too) done right it could increase the efficiency of an ICE vehicle from 30% to maybe about 50% While this wouldn't "triple the MPG" this would still be a major breakthrough. Nothing against the laws of thermodynamics here though.

    I know we get a lot of perpetual motion nuts presenting somewhat like this, but I think we may be a bit too sensitive to it, this one doesn't claim anything that violates any laws of physics just yet. That said, I'm a bit sceptical and would reserve judgement until more info is presented.

    Other posters are right though, it's pretty close to useless on a pure EV, look at the hybrid vehicles.
     
  6. AndreN

    AndreN Member

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    I just did a few Google searches for "seebeck device 40%" and "seebeck device breakthrough" covering the last month and found nothing except this forum page. The original poster needs to supply more information.

    Also note current thermoelectric generators are between 5% and 8% efficient (wikipedia). If someone built one that was 40% efficient, that would be a breakthrough, but that seems very unlikely.
     
  7. RichardC

    RichardC Cdn Sig & Solar Supporter

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    Green1, I have reviewed and debunked a number of such schemes over the years and know generally that the temperature differentials required to achieve that level of efficiency is not available from waste heat (which tends by definition to be low grade). The second law of thermodynamics is generally expressed as follows:

    In its application, the second law of thermodynamics limits the efficiency with which a heat engine can operate to the theoretical efficiency determined using Carnot's theorem, which may be summarized as follows:

    See: Carnot heat engine - Wikipedia, the free encyclopedia

    Thus the maximum theoretical efficiency is determined by the ratio (in degrees Kelvin) between the hot and cold reservoirs. Assuming a cold reservoir at an ambient temperature of 20 degrees C (approximately 293 degrees K or 68 degrees F) in order to achieve 40% efficiency the hot reservoir would have to provide energy at a temperature in excess of 216 degrees C (489 degrees K or 421 degree F). In practice, actually efficiency will be well below the maximum theoretical efficiency. In the case of non-ICE vehicles, it is not apparent from what source heat at such temperatures would be available? In the case of ICE vehicles, tests have demonstrated that the exhaust contains less than 30% of the input energy (see: http://ijeit.com/vol%202/Issue%2012/IJEIT1412201306_18.pdf) and any increase in the temperature of the engine block would serve to reduce the maximum possible efficiency of the ICE engine.
     
  8. Johan

    Johan Took a TSLA bear test. Came back negative.

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    Interesting idea johncarberry. As always the question arises: how many alternators would one need?
     
  9. green1

    green1 Active Member

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    Why are you looking only at the exhaust? ICE vehicles also have waste heat in the radiator (it's sole purpose) and engine block.

    I agree this isn't a likely sounding breakthrough. but I disagree that it violates any laws of thermodynamics. The efficiency gains being claimed are a little unreasonable, however they are not an order of magnitude out or any such thing. The calculation I did based soley on the numbers by the original poster would imply something on the neighbourhood of 28% gain in efficiency, and while current devices are only at about 5%, several published papers already feel that 15% or so is quite achievable. That puts 28% in to the realm of highly unlikely, but not impossible.
     
  10. RichardC

    RichardC Cdn Sig & Solar Supporter

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    Green1, I agree that it is theoretically possible, but seems well beyond extremely unlikely in practice. Our current ICE powerplants represent a century of efforts to improve the performance parameters of the technology, and the Carnot theorem teaches us that attempts to extract more (higher grade) energy from the engine block or engine cooling system would reduce the efficiency of the initial combustion process, and therefore be robbing Peter to pay Paul.

    For example, assuming a 60 degree C difference were to be achievable between the engine block / cooling system (which would likely be very difficult to achieve in practice with meanigful energy flows), the maximum possible Carnot efficiency would be under 17 percent (only a fraction of which would be actually achievable in practice). Any attempt to increase that temperature difference (with a view to increasing the efficiency of the secondary process) would by definition reduce the maximum theoretical Carnot efficiency of the original combustion process. If you spend some time working through different temperature scenarios, and then look at the delta between the theoretical and actually achievable efficiencies the challenge will become clearer.

    Hence my initial response with respect to the challenges which would be posed to such a technology by the laws of thermodynamics. All of that being said, I would be absolutely delighted to see possible gains (which clearly are achievable), but would be more than surprised to see a new technology which could convert 40% of the waste energy into usable electrical power.
     
  11. Raffy.Roma

    Raffy.Roma Active Member

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    #11 Raffy.Roma, Nov 22, 2014
    Last edited: Nov 22, 2014
    Of course the second principle of thermodynamics would always be respected for ICE. Maybe they have found a way to use the wasted heat involved in the combustion. But I agree with Robert. If you want to get maximum efficiency it's better to jump the second principle of thermodynamics applying to all combustions and use electric engines.

    This way you will also have no CO2 emissions which is MUCH better for the environment.
     
  12. green1

    green1 Active Member

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    I think we all agree this is an extremely unlikely breakthrough. I just wanted to point out that it doesn't fundamentally require breaking the laws of thermodynamics as posted earlier. We are right to be extremely sceptical of such claims, but we also need to make sure that our BS detectors aren't so sensitive that someday we block out perfectly legitimate stuff too.

    Of course this particular one is also completely irrelevant to EVs anyway, because the amount of waste heat is so small as to not be worth harvesting even at much higher efficiencies.
     
  13. Johan

    Johan Took a TSLA bear test. Came back negative.

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    ... Also breakthroughs in important fields of science and technology extremely rarely come out of nowhere but rather from gradual, sometimes continuous, evolution and improvements of known concepts or technologies. It's especially rare that they come in the form of a post on a car enthusiast forum by a person who joined that forum the same hour the post was made :)
     
  14. green1

    green1 Active Member

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    While true, we aren't always up to date on every possible technology coming down the pipe. I have been blindsided in the past by some pretty promising stuff in fields that I thought I did a really good job of keeping up on.

    I'm not saying to believe every random poster that walks in. Just that we should think critically instead of just having the knee-jerk reactions. Remember, it's not the messenger that counts, it's the message. Science isn't a democracy, and real breakthroughs happen against common knowledge from time to time. Evaluate the claims, and treat them with whatever amount of scepticism is appropriate.

    I guess my problem here isn't that people don't believe the original poster (as I said, I don't either) it was the claim of violating the laws of thermodynamics. That's a specific claim, and one not warranted in this case. We all are so on guard for the usual perpetual motion scams that walk in that we lump everyone in to the same pot, and I don't think it's always fully justified. I see a difference between impossible and improbable, and I think it is an important distinction. (the former requires no further investigation because we know the answer already, the latter requires proof, and if shown, can be believed)
     
  15. RichardC

    RichardC Cdn Sig & Solar Supporter

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    Peace Green1 - I plead guilty to having made a somewhat flippant remark (which, I note, stopped well short of claiming outright that there was a violation of the laws of thermodynamics), in response to what appeared to me to be an overheated puff piece (e.g., "recently developed insight into quantum size effects ... to double or triple MPG ... with lighter weight, lower cost and far longer range"), which provided zero technical or engineering content, and also seemed to be completely inapplicable to Tesla cars (which produce no waste heat worthy of mention).

    By way of background, as an angel investor in a number of cleantech startups, I had recently been approached to invest in a seemingly similar project seeking to convert waste heat into electricity which, upon closer investigation, would have violated the second law of thermodynamics. Since I know that the maximum theoretical Carnot efficiency of the principal waste heat removal system on ICEs is around 17%, and I have subsequently determined that the current state of the art in thermoelectric generation achieves only about one sixth (or less) of its maximum theoretical Carnot efficiency, there would seem to be roughly an order of magnitude difference between that which was being claimed in the puff piece and that which is currently achievable. Even this level of efficiency would likely result in substantial parasitic losses in order to dissipate the heat from the cool side of the junction with sufficient effectiveness, which would thereby further reduce the net energy efficiency.

    Notwithstanding the foregoing explanation, I agree generally with the tenor of your remarks and hope to see greater use be made of thermoelectric generating devices (even if they don't double or triple MPG).

    The following are links to some articles on thermoelectric energy generation (which is a very interesting area of technological development):
    http://en.wikipedia.org/wiki/Thermoelectric_materials
    http://en.wikipedia.org/wiki/Thermoelectric_effect
    http://searchnetworking.techtarget.com/definition/Seebeck-effect
    http://www.customthermoelectric.com/powergen.html
    http://large.stanford.edu/courses/2010/ph240/weisse1/
    http://www.digikey.ca/en/articles/techzone/2014/apr/thermoelectric-energy-generation-takes-flight-for-aircraft-and-spacecraft-monitoring
    http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=9&cad=rja&uact=8&ved=0CFEQFjAI&url=http%3A%2F%2Fwww.komatsu.com%2FCompanyInfo%2Fprofile%2Freport%2Fpdf%2F152-05_E.pdf&ei=4FpxVICdOIXHsQTS34GwBQ&usg=AFQjCNE8iiyqCprH6dvkbTlJZBYbHzcR7A&bvm=bv.80185997,d.eXY
    http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=10&cad=rja&uact=8&ved=0CFoQFjAJ&url=http%3A%2F%2Fwww.icrepq.com%2Ficrepq%252714%2F227.14-Junior.pdf&ei=4FpxVICdOIXHsQTS34GwBQ&usg=AFQjCNF7lTwc1MShZYSF7-6Z0bimfPYzUA&bvm=bv.80185997,d.eXY
    https://www.linkedin.com/company/seebeck-technology-inc-
    https://www.facebook.com/SeebeckTechnologyInc
    http://seebecktech.com/
     

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