The Solar Stirling engine runs on direct sunlight! Depending upon the sun's incident angle, the engine typically runs at 70rpm ++ up. All the moving parts are visible. The engine show the conversion of light into mechanical movement.
The top & bottom plate is made from acrylic ,allowing sunlight or the light from a lamp to heat up the black upper side of the displacer piston. Therefore the internal air is heated to allow the engine to work according to the Stirling principle.
The low temperature-differential (ltd) Stirling engine will actually run on the heat of your hand in at cool enviroment !