This low temperature Stirling engine is a cool little device. It’s a closed cycle engine, meaning that all the working gases that expand and make it work are contained inside the cylinder unlike combustion or steam engines that expel the gas after expanding. This efficient little engine runs on nothing more than a little bit of heat. Get the bottom plate a little warmer than the top one, set the flywheel in motion and it runs, keeping the flywheel turning as long as the temperature difference is there.
This particular one can run for up to 30 minutes just from the heat of a normal cup of coffee and can even run just from the heat of your hand. It’s no perpetual motion machine but it’s definitely interesting to watch and a sure conversation piece. This Stirling engine measures 120mm tall and retails for £99.95 (about $205).