Stirling Engine

Discussion in 'Hobby Engineering' started by Mathuisella, Dec 28, 2012.

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  1. Mathuisella

    Mathuisella Member

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    Hey everyone, well i've wanted one for a while and i discovered 2x 2stroke 66cc engines in the back shed...

    so, i'm building a type A stirling engine.

    the plan:

    90 degree offset, welded together at the crank.

    one cylinder to sit inside a small steel box over a wood fire as the heat source... the other cylinder to be outside the box and with copper pipe wrapped between the fins cycling water to a radiator.


    from the output shaft i want a pulley type system with a small alternator to generate some power... to 12v car battery for storage and an inverter from 12 to 240v to power my laptop and i'll want to power the 12v pump as well to cycle the water through the cold cylinder and radiator...

    and i plan to run this on air and at 30-50 PSI to generate a nice amount of power.


    progress


    I've taken the 2 stroke engines apart and have everything laid out.

    Next step is to build the "case" to house the hot cylinder + fire which will also through a standoff will hold the engine.

    Will update in a week when i get back home
     
  2. GeeBee

    GeeBee Member

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    How are you planning to deal with the exhaust and intake ports in the barrel?

    Got plans to build a custom head for the hot side to increase heat exchange into the engine?
     
  3. Thomas505

    Thomas505 Member

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    I don't think a 2 stroke engine will be at all suitable for this - at the very least you will have to replace the piston rings. A stirling engine has VERY low power density (your proposed engine would be lucky to have > 100W I would bet) and friction is the ENEMY. The piston rings in a internal combustion engine are designed to seal very well where a stirling engine can tolerate "leakiness" in favour of lower sliding friction.

    Just my 2c - don't let me stop you trying :p but just keep this in mind :D.
     
  4. craz3d

    craz3d Member

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    so use old fucked rings? not too hard to find shitty ones.
     
  5. pipster11

    pipster11 Member

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    a guy at uni made a solar powered stirling engine for his final year thesis project
    one of the hardest parts was to work out how to test the power it was putting out because is was so little

    hopefully by using a heat source like a fire it'll improve that but he was using a parabolic mirror and it actually heated up really well

    good luck! im interested to see how this goes
     
  6. OP
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    Mathuisella

    Mathuisella Member

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    Thanks for the tips i planned to leave the existing rings in, but i would just take the rings out and see how it goes too, as it gets a really nice seal without the rings anyways

    no custom head, going to place the "hot" cylinder's head above a wood burning fire. Should be hot enough. and to see it i shall be using a spark plug to cap the end Also put cust out pieces of steel to seal up the intake and exhaust

    as above, ill test with and without rings.
    the sun gives approximately 1KW per square metre of direct sunlight, i think my wood burning heat source will be sufficient.
     
  7. Lasmi

    Lasmi Member

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    If you're burning wood why not just go steam?

    As for the stirling find someone who can do the numbers as I doubt it's going to be chugging along at all. You'll get a nice hot side but the cool side will then struggle to cool it sufficiently even with the additions. If you toned the hot side back enough, most of the way, then you just wouldn't have the power you'd need to move all that weight with that friction so I think you'll have to be much more creative with the cold side, which you can be if the engine is never going to go bang any more. I could be wrong but regardless gl and I look forward to seeing updates :thumbup:
     
  8. GeeBee

    GeeBee Member

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    The issues I can see with that is you will be heating the whole hot side and because of that you will be heating the cold side through conduction. You are going to need a serious cooling system to keep the cold side cold. It is also a lot of steel/aluminium to get the heat through and I think you may get power losses.

    Also uneven thermal expansion might play havoc with your seals and your pressurisation.

    Most of the alphas I have seen seem to have an elongated head on the hot side to which the heat is applied.

    http://www.youtube.com/watch?v=gB-OwTMzXhc

    Like that.

    Are you going to use a regenerator?
     
  9. ChiefBoss

    ChiefBoss Member

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    Are you offering your... services???
     
  10. eyeLikeCarrots

    eyeLikeCarrots Member

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    Math.... any chance of some pics ?

    (Carrots knows frack all about engines)
     
  11. rainwulf

    rainwulf Member

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    This engine wont make anywhere near the power you are thinking off.. your engine wont even turn because of the amount of friction.

    if you look at most stirling engines you are talking about graphite pistons and light weight crank shafts and stuff like that, the pistons often dont even touch the cylinder wall to reduce friction.
     
  12. OP
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    Mathuisella

    Mathuisella Member

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    I think you might be right.

    I have the parts still laid out on the glass table top out under the car port...

    and yesturday i found out i was offered the Uni course i wanted, so i'm moving house in 9 days.... unsure if i'll get it done, or if i should even spend the time.....but i'll MSpaint my idea



    Click to view full size!
     
  13. OP
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    Mathuisella

    Mathuisella Member

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    Close the thread/ delete thread please. I got rid of all my metal for the upcoming move.

    perhaps another day i'll make a stirling.
     
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