The Gymnasium
Solar Stirling Engine

The inspiration for this engine is that a building roof that is 100 meters x 50 meters (5000sq M) recieves 5000kw/hr of solar energy. Even with quite low efficency of 10% that is still 500kw. This Solar Stirling engine runs very slowly, perhaps as slowly as 1 cycle per 3 minutes.

The pressure change can be used to pump water or drive a piston engine or maybe (considering the huge air volumes) a turbine.

The roof splits the cost with the engine, and most of the interior area inside the displacer is usable for other things/ so the added cost of adding the engine is low.

Also the waste heat is saved for heating the pool water.

The Displacer Cylinder Envelope (red/blue envelope) is made of a black stretch resistant membrane and is fully inflated to a much higher pressure that is outside so that the relatively small pressure changes from the engines cycles will not change its dimensions significantly.

The Displacer Envelope (white envelope) is also made of a stretch resistant membrane and is inflated much higher pressure than the displacer cylinder so there is no effect on its dimensions from the engines cycle.

Still Unclear?
Think of a mylar (non stretchy) balloon with a smaller balloon inside.
The big balloon is the cylinder and the smaller one is the displacer.
The Sun hits the top of the outer balloon and heats it and the air inside that touches it (pressure increase).
The smaller balloon (the inner envelope/displacer) is lifted until it displaces the air away from the top of the outer balloon to the cool (pool) side (pressure decrease).
Is that clearer?

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