Click on the images below to see videos of the stirling engine running
Robert Stirling's design and most of the following variants and copies had one fact in common: They were using combustible fuels because the stirling principle usually requires a high temperature difference for efficient operation.
The Stirling engine in front of you although, is working at a surprisingly low temperature difference. You will notice that this engine will even run when placed on a hot cup of coffee or a similar heat source, because it was optimized to work at low temperature differentials. Allow it's lower side to warm up a little bit and then carefully swing it's flywheel.
You will probably find many heat sources around your househould to operate this “High Tech” - stirling engine. It may even run from the heat of your hand if the difference to the ambient temperature is high enough. Also, it may run all day from the waste heat of a computer monitor or any other electrical device.
The motion process is reversible. If you place the engine on an ice cold surface, it will run backwards. It will also run backwards if you heat the upper plate.
It has been almost natural that optimizing this stirling machine has led to a very straight forward design. Should you want to explain the Stirling principle to someone else, this engine is probably suited better than any graphics, animations or descriptions found in literature, because the side wall of the housing is made from acrylic glass. Simply turn the flywheel in 90° steps and describe, what is happening in each step. Therefore this engine is not just decorative but a great educational item for physics, thermodynamics, mechanics and engineering.
Unfortunately Robert Stirling's idea never found a real application in technology yet, because steel quality improved quickly which made steam engines safe. With decreasing energy resources and increased environmental requirements there are several promising new applications arising for the Stirling engine today. Chances are good for a bright future for the ingenious idea of the reverend from Scotland.