The Stirling's cycle and engines (motors or receptors) are known and exploited for a long time with several methods. Nevertheless, all these Stirling's engines are currently suffering from the following technical difficulties, harmful for their outputs or efficiencies :

-    Non-respect of the (P,V) diagram : mainly because the used kinematics don't achieve the isothermal, and especially isochoric stages.

-    The hot and cold zones of the engine are often in the same covering block, what entails, despite of isolating precautions, highly undesirable thermal transfers because they are directly going from the hot source to the cold source without making work the coolant fluid.

-    The regenerators, when they are used, are cumbersome, expensive, and often thermally inefficients: inertia of the heat exchanges with gas, thermal flights toward the outside. They also generate some losses by lamination of fluid.

-    The fluid is often sliding in alternative motions,sometimes blocked by valves (Ericsson's version) : yet an unidirectional out-flow without valves is preferable to limit the losses by lamination of fluid and to avoid to actuate some accessories.

-    The generated motion is generally an alternate translation ; one has to use kinematics provoking vibrations ou mechanical losses to have a continuous rotation, connected to an electrical generatoir with good output.

When they accumulate themselves, all these technical problems considerably decrease the output or the efficiency of the machine that become very lower to those of Carnot.


 

2.      To fight against the thermal losses

3.  To have a simple and efficient regenerator

4.      To make circulate the fluid in an unidirectional way

5.      To directly have a rotating motion without vibrations

6. To use materials and industrial solutions that have already given their proofs

7.  To be easy to maintain and recycle

Specifications' Overview of special Stirling's machines

 

Function n°	Criteria	Levels	Flexibility	Commentaries
1. To respect the (P,V) diagram	Follow an isothermal cold and hot stages, and isochoric Vmin and Vmax stages	relative gap = 5%	At least	This point is crucial to increase the produced energy at the same time as the thermodynamic output of the machine of Stirling.
2. To fight againts the thermal losses	To isolate the cold and hot zones To isolate the hot parts from the outside	/	/	It is about preventing the direct conduction of heat of the hot toward the cold zone and to block the radiative and conducto- convective losses of the regenerator.
3. To have a simple and efficient regenerator	Not to use grids	/	/	They are at the origin of losses of loads by lamination and their thermal inertia is ominous.
	The regenerating output RGN	RGN = 90%	Au moins	It is the only manner to stretch toward the ultimate limit of Carnot
4. To make circulate the fluid in an unidirectional way	Of preference with a continuous out-flow	/	/	It limits the losses of loads, suppress the need of valves and encourage the thermal exchanges. thermal study of the regenator (in French)
5. To directly have a rotating motion without vibrations	To use a directly rotary kinematics	mutual balancing between several machines	No more than 4 PRATL machines	Necessary for the connection of good output generators and the installation on solar parabolas.
6. To use materials and industrial solutions that have already given their proofs	steel, aluminium, usual materials Already working engines	/	/	In order to make use of the already acquired know-how.
7. To be easy to maitain and recycle	Standards replacement of components, usual recycling in the re-use of metal path.	/	/	It permits more reduced costs of  exploitation and less frequent breakdowns. It avoids the expensive and polluting extractions from ore.

            

Presentation

Stirling's cycles

State of the present art

Specifications

The SPRATL's answer

Technical details

Thermal study of the regenerator

Motors & Pumps

MPRBC Concept

Concept POGDC

Special STIRLING's engines

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