Stirling Engines- energy from hot air

Discussion in 'Designing, building, making and powering your life' started by Peter Clements, Mar 21, 2006.

  1. Peter Clements

    Peter Clements Junior Member

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    Following on from Bill Mollison’s interest in the trompe compressed air engine (air pressure created by falling water), here’s an interesting engine that converts temperature differentials into mechanical energy. Stirling engines can be found powering PV collectors that follow the sun, submarines, and yachts. It seems their only drawback is a slow start-up time, measured in minutes.

    The Stirling engine was invented by Robert Stirling, a minister of the Church of Scotland. He was worried for the well-being of his parishioners who often encountered or worked with steam engines. The boilers of steam engines of the day were known to explode and kill or maim those around the engines. Stirling went to work designing a safer engine, and in 1816, he received a patent for a new “air engine”. This new engine was much safer than the stream engine and produced more power than any steam engine of the day. Because of the nature of the engine, it could not explode.

    Animation of 2-cylinder Stirling Engine
    https://www.keveney.com/Vstirling.html

    An Australian company, Olds Engineering makes a small stirling engine for physics classes demonstrations etc…
    https://www.olds.com.au/stirling
     
  2. Richard on Maui

    Richard on Maui Junior Member

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    Saw one of these at an Aussie guys place at Auroville in southern India. He would use it to run a machine that mixed up the fermented mung beans and rice for their dosa's, a sort of pancake they eat for breakfast a lot over there. The fire to run the engine was also used to cook the dosas I think. I didn't actually see it running though.
     
  3. Peter Clements

    Peter Clements Junior Member

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    Auroville

    Richard, could you describe the town of Auroville? It sounds like a centre of alternative thinking which many of us permies gravitate towards.
     
  4. heuristics

    heuristics Junior Member

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    stirling engines

    What happens when petrol is not available?
    Article appears in Living Heritage March 2006 community newsletter (Eastbend Communications) – author credit to Graeme Quick, Australian Tractors, published by Rosenberg, 2006.

    The charcoal gas producers

    when petrol was too expensive in the Depression or severely rationed during WW2 then charcoal burners were used.
    Another name for this type of fuel production is producer gas generator.
    These date from 1600 in Europe and were used for lighting and cooking.
    The charcoal was produced by burning timber slowly in pits in the ground.
    After about a week the fire would go out and the logs that were completely charcoal would be broken up, gagged, and sold.
    Charcoal Road in South Maroota was a place where charcoal was made.

    Trucks and tractors were fitted with charcoal burners and the gas they produced would fuel the engine. During WW2 the government encouraged this type of fuel production because the raw materials were readily available. Other products such as wood, grain, dried manure could be used.

    The main disadvantages of these gas producers was reduced power, problems associated with poor charcoal quality, difficulty and time taken in starting and the bulkiness of the fuel.

    A producer gas generator was used to fuel the electricity supply to Windsor.
    Any engine could be fitted with a gas producer. Some operators mounted their burners on a trailer so it could be attacked to different vehicles.
    Producer gas was a vey cheap fule by proved to be very inconvenient to use.

    (and I know people here will raise lots of 'issues' with this technology)

    My point is that – along with the Sterling engine – “we” (as society at the mercy of Big Oil) have lost touch with lots of technologies that might have been developed if the oil companies hadn't offered “cheap” gasoline and acted in conspiracies to kill off other older and emerging alternatives.
    Once Peak Oil bites, more of these technologies will be dusted off and given another try – and adapted to “catchup” with the other technological advances that have been made.
     
  5. SueinWA

    SueinWA Junior Member

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  6. Mike_E_from_NZ

    Mike_E_from_NZ Junior Member

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  7. ho-hum

    ho-hum New Member

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    Heuristics,

    I learned to drive a truck at about 12 or 13 and the vehicle I learned in was a British truck called a Foden. The farmer [who has recently passed away] had 2 trucks that he had run on gas converters during the late 40 & 50s until petrol rationing stopped.

    From memory they were a cast iron box thing that sat on the bullbar. The one on the Foden was still attached and apparently would have worked. The farmer carted vegetables from near Mildura to Melbourne. On the return journey he carried second hand building supplies and built his house from scratch [including handmade bricks] with no drawn plans. He was a many talented man actually all of those old guys were. Nature and hard times made them that way.

    I have no idea of the efficiency of the method.

    My father in law worked cutting red gum sleepers, the offcuts were put on the riverbanks for the paddlesteamers. All of the rest of the wood was buried for charcoal. All done by hand and not much wasted.

    Cheers

    Floot
     

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