Beautiful "Coffee Engine" with Black Base

Even if you understand how it works there is still magic in this small, beautiful and incredibly efficient Stirling engine. It is driven by the difference of temperature between the top and bottom of the base which is made of black powder-coated steel. The mechanics of the model motor are so sensitively designed that they work with minimal energy input. The warmth of a human hand from below or sunlight from above are sufficient to keep the flywheel going. A clever triangular joint connects the two engine pistons and pleases the ears with its gentle metallic clicking.

This Stirling engine is also called a coffee engine because when placed on a warm (not hot!) cup of coffee it transforms its warmth into motion. Any other mild heat sources such as an Internet router or the warm light of a table lamp are also suitable. The engine also works with a source of coldness, such as a cup filled with ice cubes.

The engine is made locally in Germany and consists of 95 percent self-produced parts. In principle, a Stirling engine works by means of two pistons which are located in cylinders of different temperature and connected to the flywheel. Air can flow back and forth between the cylinders. In the colder cylinder, the air contracts and sucks the piston inwards. As a result, the piston pushes the cold air over into the warm cylinder where it heats up, expands and pushes the warm piston outwards. Together they move the flywheel which will now turn over its vertex and reverse the kinetic energy. With its momentum the flywheel pushes the warm piston back into the warm cylinder and pulls the cold piston out of the cold cylinder. As a result, the air flows back from the warm cylinder into the cold one. It contracts - and the cycle begins again.

NOTES:

The engine is built for maximum efficiency and taking advantage of the smallest differences in temperature. It is NOT built for heat sources over 75º Celsius, which means neither boiling water nor any kind of flames should be applied.

The engine is being set in motion by turning the flywheel once. Then the engine runs by itself.

The golden color parts are raw polished brass. They will darken over time and develop a beautiful authentic patina. This is not a defect and does not affect the functionality. The onset of patina can be removed by polishing if desired.

With long and frequent use of the engine, it will eventually be necessary to clean moving parts such as ball bearings, cylinders, pistons and spindle. Instructions for this are included.