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Heat > Sound > Electricity

  • 07-06-2007 7:05am
    #1
    silverharp
    Registered Users, Registered Users 2 Posts: 18,854 ✭✭✭✭


    16:14 06 June 2007
    * NewScientist.com news service
    * Michael Reilly

    New ways of turning heat into sound waves - and then into electricity - may be the next step toward a practical new source of alternative energy.
    [more]

    http://www.newscientisttech.com/article.ns?id=dn12000&feedId=online-news_rss20

    A belief in gender identity involves a level of faith as there is nothing tangible to prove its existence which, as something divorced from the physical body, is similar to the idea of a soul. - Colette Colfer



Comments

  • #2
    Mellor
    Registered Users, Registered Users 2 Posts: 40,220 ✭✭✭✭Mellor


    It won't really be an alternative source, just a clean up. It would be used to pick up waste heat from generators/engines etc.
    Say an engine worked at 50% efficiency, half the energy went to heat and half to usable power. By combining one of the smaller heat engines into the arrangement some of the waste heat could be picked up to improve total efficiency. Really tiny models might be able to work from sun heat.


  • #3
    Gurgle
    Closed Accounts Posts: 5,058 ✭✭✭Gurgle


    silverharp wrote:
    16:14 06 June 2007
    * NewScientist.com news service
    * Michael Reilly

    New ways of turning heat into sound waves - and then into electricity - may be the next step toward a practical new source of alternative energy.
    [more]

    http://www.newscientisttech.com/article.ns?id=dn12000&feedId=online-news_rss20
    Nice idea, but I can't see it ever working out as a practical energy supply.

    Piezoelectric actuators are expensive little gadgets. Whether minaturized or meso-scale, it would cost a fortune to build a convertor that generates a significant amount of power.

    Vibrate a piezoelectric actuator at its resonance frequency for even a few hours and it breaks. I'm sure they can improve this with the right materials but I can't see them achieving a convertor that will work for years.

    + This isn't alternative energy, you still have to generate the heat.

    Theres a reason the internal combustion engine has lasted for over 100 years.


  • #4
    Capt'n Midnight
    Moderators, Recreation & Hobbies Moderators, Science, Health & Environment Moderators, Technology & Internet Moderators Posts: 94,272 Mod ✭✭✭✭Capt'n Midnight


    Gurgle wrote:
    Theres a reason the internal combustion engine has lasted for over 100 years.
    They are cheap, and the fuel distribution system is in place. But diesels have beaten petrol engines on fuel efficiency for 100 years. But they cost more initially and aren't as responsive.

    as for extra power from heat recovery - in WWII B29's got up to 20% of their power from turbines in the exhaust stream - only starting to happen on cars.
    http://en.wikipedia.org/wiki/Wright_R-3350
    the Turbo-Compound system was developed in order to deliver better "gas milage". In these versions of the engine, three separate power recovery turbines were attached to the exhaust piping of each group of 6 cylinders, using the power not to deliver additional boost as in a normal turbocharger, but geared directly to the engine crankshaft by fluid drives in order to deliver more power. This recovered about 20% of the heat of the exhaust, (something around 500 hp) which would otherwise be wasted. This is not without cost, however, for those devices are also nicknamed "Parts Recovery Turbines" (and worse), and were another source of failures.


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