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Hot air engine heated by magnifying glass instead of flame?
Posted: Sat Dec 19, 2020 3:34 pm
by Cavalier68
I have a hot air Stirling engine model with a flame that heats a glass cylinder. I tried focusing sunlight on the glass cylinder instead of a candle flame and the engine does not work that way. I think it would be interesting to get it working using the focused sunlight. Any helpful suggestions would be appreciated. Thanks.
Re: Hot air engine heated by magnifying glass instead of flame?
Posted: Mon Dec 21, 2020 11:46 am
by Bumpkin
Hi Cavalier68 Remember that solar heat needs a good absorber before it can then conduct to air. Some solar Stirling engines purposely have windows into an internal heater matrix. If your engine is only glass at the heated portion, maybe you could just blacken it. It would still be difficult to direct heat all around the glass tube like a flame does. Bumpkin
Re: Hot air engine heated by magnifying glass instead of flame?
Posted: Mon Dec 21, 2020 5:52 pm
by Tom Booth
It can work, but it seems a very big magnifying lense is needed in order to produce enough heat for that type of "high heat" Stirling:
https://youtu.be/CDCTANU8Tfk
On the other hand an LTD Stirling can operate with just direct sunlight without any magnification:
https://youtu.be/Q1SnG_1VMTM
Re: Hot air engine heated by magnifying glass instead of flame?
Posted: Tue Jan 26, 2021 8:09 pm
by Rob1962
Very interesting.Thank you for sharing.
Re: Hot air engine heated by magnifying glass instead of flame?
Posted: Tue Jan 26, 2021 8:09 pm
by Rob1962
Very interesting. Thank you for sharing.
Re: Hot air engine heated by magnifying glass instead of flame?
Posted: Sat Oct 09, 2021 3:34 am
by Nobody
Try directing the light to the top of the piston?
Re: Hot air engine heated by magnifying glass instead of flame?
Posted: Sat Oct 09, 2021 4:48 am
by airpower
Fresnel lenses can melt glass, steel and rocks, no candle flame will produce that kind of temperature.
https://youtu.be/xyCH2T5PWUc