Engine That Uses Ice For "Fuel"

[mklotz]

In your engine, a gamma type Stirling, the displacer is driven off the crankshaft which is in turn powered by the power piston.

A later step in the evolution of the Stirling engine was the Ringbom engine. Here the displacer isn't mechanically connected in any way to the power piston; it's completely free-wheeling and activated only by the internal gas flow in the engine.

The video below shows a Ringbom I built. The displacer is housed inside the structure with the brass cylinder on top and the hot end on the bottom being heated by an alcohol lamp. As the engine runs, it bounces up and down on its own.

The brass cylinder is actually a water jacket surrounding the cold end of the displacer chamber. A small pump on the top of the frame circulates water from the reservoir into the jacket to keep the cold end of the displacer chamber cold.

It's a non-trivial engine to scratch build but, with its infernal noise, a real attention getter at exhibitions. I prefer the elegant, noiseless motion of alpha and gamma Stirlings.