Stirlingengineforum.com

Been picking away at this for a while now. It uses an unmodified 100ml glass syringe as the piston and cylinder. Displacement is adjustable from 50-100cc. All the black parts are 3d printed. The crank shaft and connecting rod are all on ball bearings.

The roughly 140cc displacer chamber is epoxy, with a hybrid epoxy/metal displacer. Performance of the chamber alone is only "ok". It achieves about 50% of PV=nRT with a "neutral" connected power piston. I have a new displacer in the works that will hopefully make this better. The chamber itself has great thermal performance. The bottleneck is creating a .5" thick displacer that can keep up.

I'll have more updates next month after some more parts come in for the updated displacer.

Front view of the mock assembled engine. Torch for scale. Detail of the crank, piston and spring dwell mechanism.

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Impressive build. Thanks.

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Thanks.

Unless my newest displacer has a significant performance boost, I can actually reach the same chamber performance by using a foil faced solid XPS foam displacer and much lower temperatures. That may prove to be the best option. Unfortunately that means the heat source must have much better temperature regulation to avoid melting.

If we can figure out a high temperature displacer that can hit 90% of PV=nRT like my small epoxy chamber, this engine will not even reach the zero point unless I add another power piston, which there are provisions for. For now the zero point will be with around a 60cc power piston.

I like what Tom is doing with high temperature displacer materials, but for this to work the displacer can't be porous, and needs to maintain complete flatness at all temperatures. It also must be rigid and lightweight. Most importantly, it must be able to maintain close to Th and Tc simultaneously on either side. Another important requirement, it must be totally dust free. I should give aircrete another go.

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https://timtinker.com/diy-refractory/

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