The fire-extinguisher stirling engine

[Stan]

Construction doesn’t come any easier than this.

[openspaceman]

I think this is based on a 60s Harwell design that was originally proposed to run off the heat from decaying radioactive fuel and subsequently taken up in the 80s to use a propane flame and run a light on a buoy.

IIRC that vibrated 2mm at about 400Hz around a phosphor bronze diaphragm and had a conversion of 10% of the heat energy to electricity. It ran for 20,000 hours with only servicing (to top up the helium working gas pressure) every six months.

I don't know why it was not developed further nor what happened to the firm that made a few.

Apart from the constant hum two of them would keep my house warm and fill the electricity gap between November and March.

Mass produced they could be affordable to replace every 2 1/2 years.

[openspaceman]

https://en.wikipedia.org/wiki/Thermomec ... _generator

I mis remembered a couple of things, it operated at 110Hz and only needed sevicing every 2 1/2 years. There is some ambiguity about sizing, I thought 4-500We