Diaphragm Stirling generator charging 12V battery.

[Junkie]

This is one of my stirling engines charging a 12V battery. The output is around 1 - 1.5 watts electrical.
The ouput is still low. around 100ma into a 12V battery.

It's made from the following:

Stainless steel cylinder approx 85 dia x 230mm.
Innertube rubber diaphragm.
Ball bearings throughout.
Stainless steel wire wool displacer (motorbike exhaust packing).
Air cored permanent magnet alternator using neo magnets, 10 coils.
Water cooling jacket.

Youtube video :
[youtube]http://www.youtube.com/watch?v=U9vPdcW_qTg[/youtube]

[fullofhotair]

that is one beautiful engine.I just cant believe how fast and powerful these homemade stirlings are becoming.The diaphram was a great leap forward.Could you please give the dimensions of the displacer?

[Ian S C]

Junkie, it will be interesting to see what the life of the diaphram is, rubber and heat don't go together to well, so it will pay to keep that end as cool as possible. Ian S C

[Jerry]

The thermal issues with diaphragms are something I've been researching lately. After seeing this video, I wonder if it's such an issue? I realize an inner tube may not survive long term, but a diaphragm made from appropriate materials could work fine, or so it appears. Ease of engineering/fabrication and replacement/alteration make diaphragms appealing to me.

[youtube]http://www.youtube.com/watch?v=PflY-AFp15c[/youtube]

[Ian S C]

Jerry, I like your last bit. I say that someone who has made no misstakes has'nt made anything, although I think it was edison that said he had not made any mistakes, it was just a stage of developement, well something like that.
I was just thinking of the use of inner tube rubber for diaphrams, If I want inner tube I just go round the corner, there's a tire repare shop and I can get as many as I need, and the thickness I want, ranging from car tires, to trucks, and earth moving machinery, or tractors, or I supply my own bicycle tubes, only thing isI have not made a diaphram motor yet, might be worth a go. Ian S C

[Ian S C]

Perhaps the diaphragm could be made of a fabric reinforced rubber like material. Might be worth looking at diaphragms from automotive fuel pumps, or gas regulators, and the like. My idea would be a fabric reinforced material pressed with concentric corrigations, to allow movement. Ian S C