The invention is about a device (1) built with rotary annular trilobic piston engines, thanks to the bi-level with inegal volumes characteristics that they offer in their generic version ; one peripheral cover (CAR), one bi-arched core (NBA) one rotary annular trilobic piston (PRA) which turns and slides between the core (NBA) and the cover(CAR), as described in the demands PCT 03.3921, and INPI 07.5990 et 07.6157 set down by Pascal HA PHAM.



    With at least 2 rotary annular polylobic piston engines, and mainly trilobic (2,2F,2C), thermomechanical conversions of Stirling can occur with an high efficiency thanks to the qualities of these machines, exploited judiciously :
1.    The maximum and minimum volumes of the Stirling cycle are simply obtained by the volume of the rooms ot the external level which is bigger than the one of the internal level.
2.    The isothermal times of the cyle are a lot better respected thanks to the convection allowed by the displacements and transfers of
the coolant fluid inside one machine(2,2F,2C), at an homogeneous temperature.
3.    The isochoric times of the cycle are perfectly respected by connecting rooms of same nature and motion between the hot machines (2C)         and the cold machines (2F).
4.    One or several regenerator(RGN), placed between the machines(2,2F,2C), thanks to opposed and unidirectional fluxes of coolant fluid, bring an excellent internal recycling of heat between the isochoric cooling and heating of the Stirling's cycle.


    The device (1) can work with any type of hot source, notably :
-   the concentration of Sun's radiance, geothermal heats, exo-energetic chemical reactions (combustion of biomass, garbages,   
    hydrocarbons…), nuclear fissions or fusions…
-   industrial vestigial heat (oven, foundries, coolant fluids, dissipative effects in engines and facilities),

    and any type of cold source, notably:
-  ambiant air, lales, rivers, underground, ice/snow…)
- or resulting of an artificial cooling.

    The invention will integrate particulary well on « Hyperthermal fall of direct solar radiance (PHRSD) » designed by the company SYCOMOREEN (France) to develop solar electricity.



    The size of the devices(1), which are Stirling engines with rotary annular trilobic piston (SPRATL) can be very variable, starting from a few score of centimeters for a domestic use to finish to a few score of meters for industrial plants.
   
The SPRATL engines perfectly enroll in the current energetical stakes of Stirling engines, more precisely :

-    valorization of multiple sources of heat, often neglected (various organic garbage, biomass, geothermics.), very difficult by usual means,

-    raise of the helio-thermo-electric path in the setting of the solar concentrating power stations,


-    domestic or industrial cogénérations, that is to say the simultaneous production and the valorization of heat and electricity,

-   optimization of thermodynamic processes by recovering vestigial heats (with combined cycle, for example: power stations
     electric, cars.).

-    specific applications, for example the thermal energy of the seas, or the nuclear-powered ships where the cogénération and the absence of explosion in the machines of Stirling are appreciated.


The following abbreviations will be used :
-    « Tf » and « Tc » will be respectively the absolute temperature in Kelvin of the cold source and the hot source,
-    « SPRATL engine » will designate the Stirling engine with rotary annular trilobic piston in conformity with the invention (1).

    Numerous precisions will be brought in the following desciption, chronologically treating the themes : thermodynamic cycles of Stirling, state and limits of the present art, proposed solutions (recall of the features of the PRATL machines, clearing on their exploitation in cycle of Stirling, stake in series and parallel of several PRATL machines, conversion of the motion, precautions of thermal insulation, principle and advantages of the regenerator, stemming of the rooms, extension to rotary annular polylobic pistons), measurements and applications of the present invention.