`Sunwash´

A Liquid Piston Sterling Engine powered by sunlight. Burghausen, Bavaria 2004. Height 3.00m.

Sunwash is a motor, that drives nothing but itself. It consists almost of nothing but liquid and air. The fuel is sunlight, directly turned into mechanic energy. A large amount of water rythmically swaying up and down gives the impression of an enormous potential of energy just idly playing with itself. There are no moving mechanical parts in the installation- only the solar collector shows that heat is taking its influence on the action. Hundred years ago the Stirling Engine was a well known technique, it was widly deployed and advanced in many ways. It is slightly less efficient compared with a petrol engine, yet it´s great advantage is that it can run at low temperatures by solar power.

As soon as the collector heats the air above the heat exchanger inside the glass casing the air pressure will rise. The water level starts to swing up and down gently. The air pressure pushes the liquid of the semicircular `displacer liquid column´ into the outer glasstube `working column`, the swingback caused by gravity eventually turnes the movements into a constant oscillation growing more and more powerful : 900 liters of silicone oil as a substute for water sway up and down in the sculpture and give the feeling of a very slow down beat rythm generated by nature.