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A Sound Way To Turn Heat Into Electricity

sciencedaily.com — University of Utah physicists developed small devices that turn heat into sound and then into electricity.

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  • silverchrysalis, on 10/11/2007, -0/+28didn't monsters, inc, kind of use this concept?

    • *jooloop*, on 10/11/2007, -0/+17Yea, minus the heat.
    • BeyondGoodNEvil, on 10/11/2007, -0/+4The sun is real hot, maybe we could use it somehow? We just need to have a plastic tube long enough.
    • b3mus3d, on 10/11/2007, -0/+7"The sun is real hot, maybe we could use it somehow"
      We already do. For like, everything.
    • BeyondGoodNEvil, on 10/11/2007, -0/+1We use it for like, everything... except detecting sarcasm. The sun, or at least its defenders, aren't very good at that.
  • zaibatsu, on 10/11/2007, -0/+1Great find!
    • Hello1024, on 10/11/2007, -1/+0Not so great when you consider the efficiency. It's not like microphones are great at converting sound to electricity, since they only output micro or miliwatts even for loud sounds. Pitzio crystals are slightly better, but still not great efficiency.

      The only thing going for this technology is there's no other efficient way to convert heat to electricity with no moving parts, so even a low efficiency device may compete with other methods (eg. a thermocouple).

      As soon as you need this on a medium or large scale, and moving parts are allowed, a conventional turbine system like is used in power stations becomes viable. I'm surprised we haven’t seen development of tiny turbines (where the whole thing is contained in something the size of a matchbox), which use other materials with different boiling points so they can work with smaller temperature differences (eg. from 65C to 20C in a laptop). I realise that there is someone’s law which says efficiency is proportional to temperature difference among other things for any heat engine.
    • BigT9010, on 10/11/2007, -0/+0In the most ideal engine case, that of a Carnot engine, the best obtainable efficiency in a reversible process is (Hot Temp - Cold Temp)/ Hot Temp
      so for 65C to 20C, which is 338K to 293K, the absolute best efficiency one could expect is about 13.3%. This low efficiency would be my guess why turbine systems just aren't worth the money in cases like this. If this sound intermediate could be cheaper and has anything close to this efficiency (lower actually, since 13.3% is very ideal), there could be many uses for this technology.
  • airwalkery2k, on 10/11/2007, -0/+16Perhaps my piping hot car after sitting in the sun can finally do something useful?
    • wushu18t, on 10/11/2007, -0/+1which means, phoenix, the next solution for power.
    • licoricewhip, on 10/11/2007, -0/+1Yeah, then the middle east would be the world's major exporter of electricity!
  • Spaceomega, on 10/11/2007, -7/+1Okay, it can't be just me to think this - at first I thought the picture was a "penis pump."

    Great to see new ways to get energy though : )
  • LeafsIn07, on 10/11/2007, -3/+22Sweet, I can use my MacBook to power a couple of city blocks.
  • oilcan, on 10/11/2007, -5/+4a 'sound' way to turn heat into electricity. cute play on words :P

  • palehorse864, on 10/11/2007, -2/+9This would be great for PC's. Cool your processor while you take all that waste heat and put it back into the system. Also, imagine this as an air conditioner. Take heat from your room and keep extra power in your house.
    • anonydigg, on 10/11/2007, -2/+190 degree minimum heat difference
    • CeeJayDK, on 10/11/2007, -0/+4@ anonydigg : If you had read the article you would have seen that they found a way to improve the device so it would work with a much smaller themal difference making, it possible "..to cool laptop computers and other electronics that emit relatively small amounts of waste heat"

      palehorse makes a good point and I think it would also work nicely in cars.
    • chrislewis, on 10/11/2007, -0/+1For us metric-users, this comes to 32 degrees.

      I know my pc runs at at least at 60 degrees.
    • quarsaw, on 10/11/2007, -0/+2@palehorse

      extracting work from something hotter than ambient and cooling something below ambient are two very different things.
  • cuoops, on 10/11/2007, -0/+3source - http://www.unews.utah.edu/p/?r=053007-1
  • phenolholic, on 10/11/2007, -1/+9nowhere does it give a conversion to quantity of heat -> amount of sound -> voltage
    i'm thinking the apparatus, although it looks like a bong (sorry, subliminal comment), is rather efficient at converting heat to sound. however, how much sound (say 1dB) is needed to produce 1 eV? 1 V? i'm thinking alot. similar to the perpetual machine. good start though.
    • danconia, on 10/11/2007, -0/+3From what I understand you need a HUGE amount of sound energy to make a decent power source. I didn't see any mention of this in the article (naturally). I remember hearing some ridiculous stat like all we say during our lives create enough power to drive a car like 50 feet or something stupid like that. Someone please correct me if I'm wrong, I'd love to see the actual statistic.
    • drmonkey, on 10/11/2007, -0/+2The article wasn’t very detailed,

      No mention of watts to watts conversion efficiency,
    • Manhigh, on 10/11/2007, -0/+1Exactly. I doubt this thing has the efficiency of, say, a Stirling engine yet.
  • shoota, on 10/11/2007, -4/+2finally we can turn this global warming business into a way to produce power.
  • Nocterminus, on 10/11/2007, -0/+2This really has the potential to be significant if it can prove to convert heat energy to electrical efficiently . I've worked with piezo electric acoustic drivers for MSL sound systems and they have amazing properties. It's basically a pressure sensitive crystal.
  • phenolholic, on 10/11/2007, -1/+5also, this project seems to be focused on the heat -> sound pathway, (similar to the mechanics of a pressure cooker), but it didnt really focus on the sound -> electricity pathway. it seems like it just disregarded that part to a piezoelectric transducer which converts pressure (from sound) to an electrical potential. if such things already exist, then why isnt it employed in todays electronics? forget the heat -> sound pathway, although such pathway would increase sound, in turn increasing electricity, but why isnt there piezoelectric transducers covering my cpu fan? why even convert it to sound? why not just use pyroelectric transducers (devices that create electrical potential when heat is applied)
  • HappyScrappy, on 10/11/2007, -3/+2I dunno. They said you need as "little as" 90F. A 90F difference is on the border between waste-grade heat and quality heat. I'm afraid this won't be terribly useful for converting waste heat into electricity.
  • Illuminati, on 10/11/2007, -0/+1fascinating idea
  • GreySpec, on 10/11/2007, -0/+2Yes, they have been perfecting this technology for about 20 years... The only difference is that they have optimized the resonators to generate much louder frequencies, whereby increasing electrical generation. It is still years away from replacing current PV cell or any similar technology. It will be interesting to see how this research progresses in the near future!
  • BrianNowhere, on 10/11/2007, -1/+6Why not convert sound straight into electricity and skip the heat part? We could power the world with old Black Sabbath and Zeppelin records.
  • RProgrammer, on 10/11/2007, -0/+3They also said that the pressure of the gas is inversely related to the required temperature difference.
    So with more pressure, you can decrease the difference from 90F. But you're right, it is somewhat odd that they would site 90F as "a little", maybe previous devices required far more impractical differences..
  • oepapel, on 10/11/2007, -1/+7It seems like the heat -> sound is the central part of the research. They just slap on a piezo device at the end.

    I have a really hard time believing that going from heat -> sound -> electricity is more efficient than heat -> electricity. Especially since they mentioned that a byproduct of the process was high frequency noise. That tells you right there that the energy transfer from sound -> electricity is really really low.

    Why not use thermocouples again? The article really missed the most obvious question...
  • b33x, on 10/11/2007, -0/+0sounds cool!

    now i can use my body heat to charge my ipod, or mobile phones, or some led torch light!
    it also can maximize the solar power, not only light can be covert to power, even heat!
  • Ruckgesicht, on 10/11/2007, -0/+2So that's how they did it in Dune.
  • 89vision, on 10/11/2007, -0/+2Wow! I took a physics of audio and visual from this guy a couple years ago. He's pretty eccentric and it was definitely one of the more interesting classes I took in college.
  • AlexApetrei, on 10/11/2007, -1/+1interesting stuff, i never really like PV, the efficiency never seams to be worth the investment, maybe with this stuff we could get a little closer ...

    ... still , why not just heat into electricity straight, no sound ?
  • bobotheking, on 10/11/2007, -0/+2Why not use a Stirling engine?

    http://en.wikipedia.org/wiki/Stirling_engine
    • DrDragun, on 10/11/2007, -1/+4Based on the pic, that should be renamed ***** 'n balls engine
    • Valleye, on 10/11/2007, -0/+1Stirling engine will lose efficiency over time as the piston wears. The tolerance required to build it are higher than this application too.

      All FTA.
    • Manhigh, on 10/11/2007, -0/+3Yeah, but if they start out with an efficiency, or output, significantly higher than this method, does that matter? This is great and I hope it scales well, but that's yet to be proven.
  • NoobSaibot, on 10/11/2007, -2/+0hmm, I wonder if they could use this technology to create a portable, electronic weed vaporizer.... :-D
  • JohnnyXmas, on 10/11/2007, -3/+1@BrianNowhere:

    "Why not convert sound straight into electricity and skip the heat part?"

    NOOO!!!! That would allow people to finally justify their STUPID ***** RINGTONES! I guarantee you there would be WAY more shootings on public transportation due to some jackass "charging his phone" by playing the intro to Zepp's "Immigrant Song" over, and over, and over, and over. . .


    "AhhhAHahhhhhhhAAAAHHHhhh. . .AhhhAHahhhhhhhAAAAHHHhhh. . .AhhhAHahhhhhhhAAAAHHHhhh. . .AhhhAHahhhhhhhAAAAHHHhhh"


    "B L A M!!"
  • Hello1024, on 10/11/2007, -0/+0Why won't my comments submit!!!

    EDIT: anyoine else finding they can't reply to any thread - only make a new one?
  • fatfishy, on 10/11/2007, -0/+1Some nice diagrams of Dr. Orest Symko work at his university page:

    http://www.physics.utah.edu/~woolf/acoustics/bio.html
  • gedw99, on 10/11/2007, -0/+2There are 6 devices i know of in the world that convert heat to electricity.

    Most are nano based and the best i know of converts at a 70% of carnot efficiency. This means that you can produce huga amounts of electricity just from normal water based solar collectors ( which are cheap).
    This IS disruptive technology and will be a game changer.

    Solar cells are not going ot be able to compete att all.

    Honda and Intel have already signed contracts to use these heat chip. Honda will be using them to convert heat in the exhaust into elec.
    Intel will be using them to cool laptops and add to battery power.

    AT work, I have one on the bench hooked up to a thermal heat pump at the moment and it very easy to setup.

    This stuff is a the game changer in my opinion.



  • leffunov, on 10/11/2007, -0/+1God damn it!! I knew someone would steal my idea!!
  • permagenix, on 10/11/2007, -0/+0GEDW99:
    Can you please provide links to the 6 devices you mention? Especially interested in e-gen from water-based solar collectors.

    Thanks
    • stu93, on 11/13/2007, -0/+0By the summer of 2008 my solar heated home will have too much hot water. How can I get some details on converting to electricity?
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