- - - - - - - - - Why create a new Stirling engine? - - - - - - - - -

LOW TEMPERATURE STIRLING ENGINE

You can easily find this Stirling engine working with a low temperature difference between the hot and cold source.

It is presented the operation of this engine.

The hot source is located in the lower part and the cold source is in the upper part.

(A hot source can be hot water in a cup and the cold source the ambient air.)

A driving piston provides driving torque via a crank rod system

A displacement piston is driven by a system of connecting rods and cranks. The two crank systems are offset by 90 degrees.

For 90 degrees (1/4 turn), when point A moves to point B, the piston moves almost nothing.

When point B moves toward point C, the piston moves a long distance.

The gas is in contact with the cold source. The driving piston will move down to compress the gas. The displacement piston hardly moves at all.

The driving piston does not move. The displacement piston will move up to transfer the gas downwards.

The gas that has been compressed, undergoes a rise in temperature.

The displacement piston does not move.The gas has been compressed and subjected to a rise in temperature.

It's at maximum pressure. This pressure allows the driving piston to be pushed to drive.

The driving piston does not move.the displacement piston will move down to transfer the gas upwards to cool it down.

Regenerator

One solution to create a regenerator for this type of engine is to force the gas to go through the displacement piston.

The piston is hollow and contains steel wool.

The steel wool recovers heat during the cooling process of the gas and restores this heat during the heating process.

Analysis

The gas is permanently in contact with the hot and cold source. The heat transfer times only take place during a quarter of a revolution of the engine.

In order for the regenerator to be efficient, a body with low thermal inertia and large exchange surfaces is required so that it can absorb the heat immediately and release it later. These constraints create a dead volume that hinders the engine's performance.

Patent-protected two-stroke Stirling engine : Ref. I.N.P.I. : FR1915384 - For more information, please contact the association: execo@caramail.com