FR3106151A1 - THERMOELECTRIC GENERATOR FOR PIPING AND INTENDED TO PARTICIPATE IN THE THERMAL INSULATION OF THE PIPELINE - Google Patents

Abstract

The pipeline thermoelectric generator (100) includes thermal insulator and thermoelectric modules (102). The thermoelectric generator (100) comprises a first ring (103) at least in part thermally conductive, the first ring (103) being intended to surround the pipe. The thermoelectric generator (100) comprises a second ring (104) at least in part thermally conductive, the second ring (104) surrounding the first ring (103). The thermal insulator connects the first ring (103) to the second ring (104). Each thermoelectric module (102) is placed in the thermal insulation. Each thermoelectric module (102) is thermally coupled to the first ring (103) and each thermoelectric module (102) is thermally coupled to the second ring (104). Figure to be published with the abstract: Fig. 2

Description

THERMOELECTRIC GENERATOR FOR PIPELINE AND INTENDED TO PARTICIPATE IN THE THERMAL INSULATION OF THE PIPELINE

Technical field of the invention

The technical field of the invention relates to the field of the recovery of energy, in particular electrical energy, by exploiting a thermoelectric effect from a pipe used to transport a fluid, for example a petroleum product such as oil or gas, and the environment outside the pipeline. More particularly, the invention relates to a thermoelectric generator for a pipe comprising a thermal insulator and thermoelectric modules.

State of the art

There are thermoelectric generators adapted to the recovery of energy on pipes, and possibly adapted to underwater applications to, for example, supply electric current to supply sensors positioned near a corresponding thermoelectric generator.

When a pipeline allows the transport of a fluid at a certain temperature, it is preferable to avoid transfers of thermal energy between the interior of the pipeline and the exterior of the pipeline. This is particularly true for applications for transporting petroleum products, for example petroleum, in subsea pipelines. Indeed, in this case, the oil circulating in the pipeline must remain hot, for example at a temperature of between 70°C and 80°C, to avoid the formation of clogs in the pipeline while the sea water surrounding the pipe can be at a much lower temperature, for example 4°C. For this, it is known to thermally insulate the pipes, but such thermal insulation is generally incompatible with the generation of electric current by thermoelectric effect using the temperature of the fluid and the temperature of the sea water.

The international patent application published under the number WO 2015/075426 A2 describes an electricity generation device for a pipeline intended to be placed on the seabed. Such an electricity generation device comprises a collar assembled to the pipe and on which is mounted a support of thermoelectric modules. A thermal insulation layer is formed on the collar at a distance from the pipe to limit heat loss to the environment outside the electricity generation device and to promote the supply of heat to the support of the thermoelectric modules. A drawback of this solution is that the thermoelectric modules are subjected to a temperature difference which is not optimized due to heat losses, between the collar and the thermoelectric modules, from the support to the external environment. This temperature difference corresponds in particular to a temperature difference on either side of each of the thermoelectric modules, the greater this temperature difference, the more the thermoelectric modules generate a significant electrical power.

French patent FR2758009 B1 describes an underwater thermoelectric generator with thermoelectric modules arranged in sleeves. The thermoelectric modules are here placed in basins machined directly in a pipe, this pipe being used for the circulation of petroleum products. The disadvantage of this solution is that it can only be implemented if a machined pipe is available. Such machining is expensive and can damage the pressure resistance of the pipeline. Furthermore, French patent FR2758009 B1 does not offer a satisfactory solution for thermally insulating the pipe because, although thermal insulation is provided, this thermal insulation is used to redirect the thermal flow towards the thermoelectric modules without specifically thermally insulating the channeling.

Object of the invention

The object of the invention is to promote the generation of electrical energy by a thermoelectric generator when it surrounds a pipeline transporting a fluid while allowing the thermoelectric generator to thermally insulate the pipeline locally at the place where it is fitted to this pipe.

To this end, the invention relates to a thermoelectric generator for a pipe, said thermoelectric generator comprising a thermal insulator and thermoelectric modules, this thermoelectric generator being characterized in that: the thermoelectric generator comprises a first ring that is at least partially thermally conductive , the first ring being intended to surround the pipe; the thermoelectric generator comprises a second ring which is at least partially thermally conductive, the second ring surrounding the first ring; the thermal insulator connects the first ring to the second ring; each thermoelectric module is placed in the thermal insulator; each thermoelectric module is thermally coupled to the first ring and each thermoelectric module is thermally coupled to the second ring.

Such a thermoelectric generator has the advantage, when associated with the pipeline it surrounds, of limiting heat loss from the pipeline by suitably thermally insulating it while allowing efficient production of electrical energy by thermoelectric effect.

The thermoelectric generator may further include one or more of the following features:
- the thermoelectric generator comprises thermal diffusers arranged in the thermal insulation, each thermoelectric module being thermally coupled to one of the first and second rings via one of the thermal diffusers;
- each heat diffuser comprises a first part adopting the shape of a truncated cone and a second part arranged in the continuity of the truncated end of the truncated cone, said second part extending from said first part so as to present a face of bonding to one of the thermoelectric modules, said bonding face having a surface of dimensions less than or equal to a surface of said thermoelectric module with which the bonding face is bonded;
- for each thermoelectric module, the thermal coupling of said thermoelectric module to the second ring is ensured via one of the thermal diffusers;
- for each thermoelectric module, the thermal coupling of said thermoelectric module to the first ring is ensured via one of the thermal diffusers;
- for each thermoelectric module, the thermal coupling of said thermoelectric module to the second ring is ensured via one of the thermal diffusers and the thermal coupling of said thermoelectric module to the first ring is ensured via another of the diffusers thermals;
- the thermoelectric generator is such that: the first ring comprises a plurality of first heat absorbers interconnected; the second ring has a plurality of interconnected second heat sinks; each thermoelectric module is thermally coupled, on the one hand, to one of the first thermal absorbers and, on the other hand, to one of the second thermal absorbers;
- the thermal insulation is formed by a thermally insulating material having a thermal conductivity of between 0.01 Wm ^-1 .K ^-1 and 0.2 Wm ^-1 .K ^-1 ;
- the thermal insulation has a compressive strength strictly greater than 50 MPa;
- the thermoelectric generator has a central axis surrounded by the thermal insulation, and each thermoelectric module has a thermal resistance greater than or equal to where N is the number of thermoelectric modules, R ₁ is the distance orthogonally separating the central axis from an internal face of the thermal insulator proximal to the central axis, R ₂ is the distance separating orthogonally the central axis from relative to a face of the thermal insulator distal from the central axis, λ is the thermal conductivity of the thermally insulating material of the thermal insulator, and H is the dimension of said thermoelectric module measured parallel to the central axis;
- The first ring has two opposite flanges, the two flanges being at a distance from the thermal insulation.

The invention also relates to an installation for the transport of a fluid, preferably petroleum, comprising a transport pipe, preferably underwater, of the fluid. This installation comprises at least one thermoelectric generator as described, said thermoelectric generator surrounding the pipe.

The installation may comprise a sheath configured to thermally insulate the pipeline and to generate electric current by thermoelectric effect, the sheath comprising a plurality of thermoelectric generators each surrounding the pipeline.

For example, the thermoelectric generators are arranged successively along the pipe and, for any pair of adjacent thermoelectric generators: the first rings of the thermoelectric generators of said pair may each comprise a flange; said flanges are connected; the sheath may comprise an annular thermally insulating member arranged between the thermoelectric generators of said pair, the thermally insulating member comprising an annular groove into which said collars are inserted.

For example, for any pair of adjacent thermoelectric generators, the sheath includes a clamp, said clamp clamping the thermally insulating member arranged between the thermoelectric generators of said pair of adjacent thermoelectric generators.

The invention also relates to an elementary device for the manufacture of a thermoelectric generator for a pipeline. This elementary device comprises: a first heat absorber configured to partially surround the pipe and preferably to cooperate with part of the pipe; a second heat absorber arranged at a distance from the first heat absorber; a thermally insulating element connecting the first thermal absorber to the second thermal absorber; at least one thermoelectric module arranged in the thermally insulating element between the first thermal absorber and the second thermal absorber, the thermoelectric module being thermally coupled to the first thermal absorber and thermally coupled to the second thermal absorber.

For example, the elementary device comprises a thermal diffuser extending in the thermally insulating element, the thermal coupling of the thermoelectric module to the first thermal absorber being ensured by means of the thermal diffuser, the thermoelectric module being in connection with the second absorber thermal.

For example, the elementary device comprises a thermal diffuser and an additional thermal diffuser each extending into the thermally insulating element, the thermal coupling of the thermoelectric module to the first thermal absorber being ensured via the additional thermal diffuser and the thermal coupling from the thermoelectric module to the second thermal absorber being provided via the thermal diffuser.

For example, the elementary device comprises a thermal diffuser extending in the thermally insulating element, the thermal coupling of the thermoelectric module to the second thermal absorber being ensured by means of the thermal diffuser, the thermoelectric module being in connection with the first absorber thermal.

Other advantages and features will become apparent from the detailed description that follows.

Brief description of the drawings

The invention will be better understood on reading the detailed description which follows, given solely by way of non-limiting example and made with reference to the appended drawings listed below.

FIG. 1 represents, according to a perspective view, a thermoelectric generator according to a particular embodiment of the invention.

FIG. 2 represents, according to a perspective view, the thermoelectric generator of FIG. 1 for which a thermal insulator has been removed in order to visualize the interior of this thermoelectric generator.

FIG. 3 illustrates the thermoelectric generator of FIG. 1 seen orthogonally to a central axis of the thermoelectric generator, this central axis being in particular locally collinear with an axis of a pipe when this thermoelectric generator surrounds the pipe.

FIG. 4 illustrates the thermoelectric generator of FIG. 3 for which the thermal insulation has been removed in order to visualize the interior of this thermoelectric generator.

Figure 5 illustrates a simplified sectional view of part of the thermoelectric generator according to section AA of Figure 3.

FIG. 6 illustrates, in a perspective view, a particular embodiment of an installation for transporting a fluid comprising a plurality of thermoelectric generators, for example of the type illustrated in FIG. 1.

Figure 7 illustrates a longitudinal sectional view of the installation shown in Figure 6.

FIG. 8 illustrates, in a view orthogonal to the central axis of the thermoelectric generator, a particular embodiment of the thermoelectric generator for which the thermal insulation has been removed in order to visualize the interior of this thermoelectric generator.

FIG. 9 illustrates, in a view orthogonal to the central axis of the thermoelectric generator, another particular embodiment of the thermoelectric generator for which the thermal insulation has been removed in order to visualize the interior of this thermoelectric generator.

Figure 10 illustrates, in a perspective view, an elementary device that can be used to form the thermoelectric generator in particular of the type of Figure 1.

FIG. 11 illustrates, in a perspective view, the elementary device of FIG. 10 without its thermally insulating element in order to view the interior of this elementary device.

In these figures, the same references are used to designate the same elements.

detailed description

The thermoelectric generator according to the present invention proposes a solution making it possible to thermally insulate a pipeline while allowing efficient generation of electrical energy, in particular by placing thermoelectric modules in a thermal insulator.

Preferably, this solution is very particularly interesting for an application on an underwater pipe making it possible to extract a fluid such as, for example, a petroleum product. Indeed, such a pipe is generally thermally insulated to avoid clogging or sedimentation of the fluid it transports in the event of a stoppage of the extraction of the fluid via this pipe. Placing the thermoelectric modules in the thermal insulation makes it possible to limit thermal leaks to the outside of the pipe, and to combine the function of thermal insulation and the function of thermoelectric generator which are generally contradictory. Indeed, the thermoelectric generator must guarantee a good heat exchange between the thermoelectric modules and two heat sources at different temperatures (because these thermoelectric modules exploit a temperature difference to generate electricity), while thermal insulation allows to limit as much as possible the exchange of heat between these two sources of heat which the fluid circulating in the pipe and, for example, the sea water forming the environment outside the pipe can form respectively.

In the present description, by “included between two values”, it is understood in particular that the two values limiting the corresponding range are included.

In the present description, by “one of the elements A and B”, it is understood the element A or the element B. Following this formulation “one of the elements A and B”, “the other of the elements A and B” corresponds to the element different from that previously chosen among element A and element B.

In the present description, by "based on", it is particularly understood "comprises at least a majority" or, if applicable, "consists of" in the sense that "an element based on a material" can be , if applicable, formed solely by this material.

In the present description, by "thermal coupling", it is preferably understood "thermally connected", that is to say that there is a link allowing a heat transfer in particular between two thermally coupled elements. For example, this link can be a link between the two thermally coupled elements, for example this link can be a contact between these two elements or a bonding of these two elements, or even a thermal paste (for example a silver paste) interposed between and in contact with these two elements. Alternatively, the link may include a third member, also called a thermal diffuser, interposed between the two thermally coupled elements to allow the transfer of thermal energy between these two elements via this third member.

Thermal energy is in particular heat.

In the present description, the “central axis” of a ring or a crown is in particular the axis which is surrounded by this ring or this crown and which passes through the center of this ring or this crown. Preferably, the ring or the crown has a profile in the shape of a circle and the center of this circle corresponds to the center of the ring or of the crown. Thus, the thickness of the ring or of the crown is in particular measured orthogonally to its central axis and the width, also called transverse dimension or axial dimension, of the ring or of the crown is in particular measured parallel to its central axis.

The invention relates to a thermoelectric generator 100 for pipe 1000, examples of embodiments of which are illustrated in particular in FIGS. 1 to 9. For example, pipe 1000 (visible only in FIGS. 6 and 7) is a steel pipe. Pipe 1000 is in particular a pipe for transporting a fluid. This thermoelectric generator 100 comprises the thermal insulation 101 (notably visible in Figures 1, 3, 5, 6 and 7) preferably configured to surround the pipe 1000. Preferably, the thermal insulation 101 is annular and preferably circular. In other words, the thermoelectric generator 100 may comprise a crown of thermally insulating material, this crown forming the thermal insulator 101, such a crown makes it possible to locally thermally insulate the pipe 1000 when the thermoelectric generator 100 is mounted therein as illustrated in FIGS. 6 and 7. Hereafter, "thermal insulator 101" preferably refers to the crown of thermally insulating material. The thermoelectric generator 100 comprises the thermoelectric modules 102 (visible in particular in FIGS. 2, 5, 7, 8, 9 and 11) each placed (that is to say arranged) in the thermal insulator 101. The thermoelectric generator 100 comprises a first ring 103 at least partially thermally conductive, the first ring 103 being intended to surround the pipe 1000 and preferably to be thermally coupled to the pipe 1000 to capture heat from the pipe 1000, in particular heat from the fluid circulating in this pipe 1000. For example, the thermal coupling of the first ring 103 to the pipe 1000 can be ensured by a contact of the first ring 103 with the pipe 1000. According to another example, the thermal coupling of the first ring 103 to the pipe 1000 can be ensured by the interposition of a thermally conductive adhesive, a thermal paste such as for example a silver paste, or a flexible graphite element (also called a flexible graphite pad), connecting the first ring 103 to the pipe 1000 and whose function is to optimize the heat exchange from the pipe 1000 to the first ring 103. The thermoelectric generator 100 comprises a second ring 104 at least partially thermally conductive. The second ring 104 surrounds the first ring 103. The thermal insulator 101 connects the first ring 103 to the second ring 104. According to another formulation, the thermal insulator 101 separates the first ring 103 from the second ring 104. Thus, the insulator 101 is preferably in contact with the first ring 103 and in contact with the second ring 104. Each thermoelectric module 102 is thermally coupled to the first ring 103. Each thermoelectric module 102 is thermally coupled to the second ring 104. In other words, the generator 100 thermoelectric is configured to subject each of the thermoelectric modules 102 to a temperature difference using two heat sources, located on either side of the thermal insulation 101, and using the first and second rings 103, 104 which capture thermal energy from these two heat sources. This has the advantage of combining the function of thermal insulation of the pipe 1000 and of current generation by thermoelectric effect in an effective manner while limiting the heat losses from the pipe 1000 to its external environment through the thermoelectric generator 100 since the thermoelectric modules 102 are placed in thermal insulation 101 and are preferably coated with thermal insulation 101.

In a configuration of use of the thermoelectric generator 100, the latter is mounted on the pipe 1000 then called pipe 1000 for transporting the fluid F (FIGS. 6 and 7) represented schematically by wavy arrows, this fluid F forming one of the two heat sources and the environment outside the pipe 1000 and located around the thermoelectric generator 100 forming the other of the two heat sources. Thus, the thermoelectric generator 100 can adopt the general shape of a crown.

In other words, the thermoelectric generator 100 is capable of supplying an electric current by Seebeck effect thanks to the thermoelectric modules 102 and to the temperature difference which exists between the two heat sources. The thermoelectric generator 100 is therefore configured, in the configuration of use, to subject each of the thermoelectric modules 102 to a temperature difference between a first temperature resulting from a thermal energy captured by the first ring 103 and a second temperature resulting from a thermal energy captured by the second ring 104. The thermal energy captured by the first ring 103 comes from the temperature of the fluid, then forming one of the heat sources, circulating in the pipe 1000 and the thermal energy captured by the second ring 104 comes from the external environment, then forming the other of the heat sources, to the pipe 1000 such as for example sea water. For this, each thermoelectric module 102 can comprise first and second faces opposite sides, the thermal coupling of each thermoelectric module 102 to the first ring 103 taking place via the first face of the thermoelectric module 102 and the thermal coupling of each thermoelectric module 102 to the second ring 104 taking place via the second face of the thermoelectric module 102 with a view to subjecting the thermoelectric module 102, between its first and second opposite faces, to a temperature difference allowing it to generate electricity in the configuration of use.

It follows from what has been described above that the function of the first ring 103 is to recover, in the configuration of use, thermal energy from the fluid flowing in the pipe 1000. This is why the first ring 103 is at least partially thermally conductive and is configured to surround pipe 1000 and to be thermally coupled to pipe 1000. Pipe 1000 is then thermally conductive to allow heat diffusion from the fluid to first ring 103.

It follows from what has been described above that the function of the second ring 104 is to recover, in the configuration of use, thermal energy from the environment external to the pipe 1000 such as, for example, the heat energy from sea water.

In this sense, the first and second rings 103, 104 are, for example, based on steel or aluminum. Of course, any other type of material suitable for carrying out the functions of the first and second rings 103, 104 can be used. As will be seen later, the first and second rings 103, 104 can each be formed by an assembly of parts, hereinafter called thermal absorbers 108, 109. Preferably, these heat absorbers 108, 109 are steel-based or aluminum-based and even more preferably made of steel or aluminum.

The first and second rings 103, 104 may comprise a material having a thermal conductivity strictly greater than 5 Wm ^-1 .K ^-1 . Preferably, the first and second rings 103, 104 are each based on a metallic material having a thermal conductivity of between 20 Wm ^-1 .K ^-1 and 400 Wm ^-1 .K ^-1 . Such thermal conductivities are suitable for capturing heat.

Preferably, the first and second rings 103, 104 are coaxial, this notably making it possible to homogenize the thickness of the thermal insulation 101 between these first and second rings 103, 104 with a view to ensuring suitable thermal insulation of the pipe. 1000.

Preferably, the thermal insulation 101 has an internal circumference and an external circumference separated by a maximum separation distance defining the thickness, called "maximum thickness", of the thermal insulation 101 separating the first ring 103 from the second ring 104 This maximum separation distance is in particular measured radially with respect to the first ring 103 and in particular, where appropriate, with respect to the longitudinal axis of the pipe 1000 surrounded by the thermoelectric generator 100.

Preferably, the first ring 103 is fixed, for example by gluing, to the thermal insulator 101 in particular to the internal circumference of the thermal insulator 101. The second ring 104 is preferably fixed, for example by gluing, to the insulator 101 in particular to the outer circumference of the thermal insulator 101. Thus, the thickness of the thermal insulator 101 can correspond to the distance radially separating the first ring 103 from the second ring 104. The bonding described in this paragraph can be ensured by the material of the thermal insulation 101.

When the thermal insulator 101 is attached to the first and second rings 103, 104, it ensures the bracing of the first and second rings 103, 104.

Preferably, the thermal insulator 101 is a solid material.

The thickness of the thermal insulation 101 is preferably between 7 mm and 21 cm. This is particularly suitable for suitably thermally insulating the pipe 1000, for example when this pipe 1000 has a diameter of between 10 cm and 60 cm, in particular when this pipe 1000 is intended to be placed at the level of a seabed. If the environment outside the pipe 1000 is the air, a lower thermal insulation of this pipe 1000 can be considered compared to the case where the environment outside the pipe 1000 is sea water.

According to a particular example where the fluid circulating in the pipe 1000 is a petroleum product and for which the pipe 1000 is submerged at the level of a seabed, the temperature difference between the two heat sources used with a view to supplying a current by Seebeck effect is that which exists between the temperature of the petroleum product (for example between 45° C. and 100° C.) and the temperature of the sea water at the level of the thermoelectric generator 100 which is of course strictly lower than the temperature of the petroleum product. This temperature of the sea water is, for example, between 0°C and 10°C, and in particular equal to 4°C.

It was mentioned above how to efficiently recover thermal energies on either side of the thermal insulation 101 using the first and second rings 103, 104. There is also a need to find an effective solution to diffuse thermal energies resulting from these recovered thermal energies, always with the least possible loss up to the thermoelectric modules 102 arranged in the thermal insulation 101 with a view to subjecting each of these thermoelectric modules 102 to a temperature difference allowing it to supply current in the configuration of use thermoelectric generator 100. To meet this need, the thermoelectric generator 100 can preferably include thermal diffusers 105a, 105b (for example visible in FIGS. 2, 4, 5, 7, 8, 9 and 11) arranged in the thermal insulation 101. Each module 102 thermoelectric is thermally coupled to one of the first and second rings 103, 104 via one of the thermal diffusers 105a, 105b which, if necessary, participates in forming the corresponding thermal coupling mentioned above. Preferably, the thermal diffusers 105a, 105b extend into the thermal insulation 101. Such thermal diffusers 105a, 105b have the advantage of making it possible to concentrate thermal energy towards the thermoelectric modules 102, in particular when they are placed at a distance from the corresponding first ring 103 and/or from the corresponding second ring 104.

Each thermoelectric module 102 being placed in the thermal insulation 101, it can be:
- in connection with one of the first and second rings 103, 104 and at a distance from the other of the first and second rings 103, 104 (FIGS. 2, 4 and 8), the connection being able to be ensured by a contact of the module 102 thermoelectric with the first or second ring 103, 104 concerned, or by a thermally conductive adhesive or by thermal paste such as silver paste connecting the thermoelectric module 102 to the first or second ring 103, 104 concerned, or
- At a distance from the first and second rings 103, 104 (Figure 9).
These possibilities are described below in three exemplary embodiments.

According to a first exemplary embodiment in particular as illustrated in a non-limiting manner in FIGS. 2, 4, 5, for each thermoelectric module 102, the thermal coupling of said thermoelectric module 102 to the second ring 104 is ensured via the one of the thermal diffusers 105a. In this case, each thermal diffuser 105a preferentially extends, in the thermal insulation 101, from the second ring 104 to come into contact with one of the corresponding thermoelectric modules 102. Preferably, the thermoelectric modules 102 are each connected to the first ring 103. In other words, preferably, for each thermoelectric module 102, the thermal coupling of said thermoelectric module 102 to the first ring 103 is such that said thermoelectric module 102 is connected with the first ring 103, this connection therefore ensures the thermal coupling. Thus, according to this example, each thermoelectric module 102 is closer to the first ring 103 than to the second ring 104. This first embodiment has the advantage of using thermoelectric modules 102 whose thickness is strictly less than that of the thermal insulation 101 so as to benefit from good thermal insulation of the pipe 1000 and facilitate the assembly of the 100 thermoelectric generator. Preferably, the thermal diffusers 105a here each extend radially from the second ring 104, in particular towards the center of the second ring 104. In FIGS. 2 and 4, the first embodiment is such that the thermoelectric generator 100 comprises so non-limiting six thermal diffusers 105a and six thermoelectric modules 102.

According to a second exemplary embodiment in particular as illustrated in a non-limiting manner in FIG. 8, for each thermoelectric module 102, the thermal coupling of said thermoelectric module 102 to the first ring 103 is ensured via one of the diffusers 105a thermal. In this case, each thermal diffuser 105a preferentially extends, in the thermal insulator 101, from the first ring 103 to come into contact with one of the corresponding thermoelectric modules 102. Preferably, the thermoelectric modules 102 are each connected to the second ring 104. In other words, preferably, for each thermoelectric module 102, the thermal coupling of said thermoelectric module 102 to the second ring 104 is such that said thermoelectric module 102 is connected with the second ring 104, this connection thus ensuring the corresponding thermal coupling. This second embodiment is a functional alternative to the first embodiment. Preferably, the thermal diffusers 105a here each extend radially from the first ring 103, in particular towards a direction opposite to the center of the first ring 103. In FIG. 8, the second example embodiment is such that the thermoelectric generator 100 comprises non-limiting manner six thermal diffusers 105a and six thermoelectric modules 102.

According to a third exemplary embodiment such as for example illustrated in FIG. 9, the thermoelectric modules 102 are at a distance from the first and second rings 103, 104. In this case, for each thermoelectric module 102, the thermal coupling of said thermoelectric module 102 to the second ring 104 is ensured via one of the thermal diffusers 105a, preferably, said one of the thermal diffusers 105a extends, in the thermal insulation 101, in particular from the second ring 104 to come into contact with the module 102 thermoelectric. Furthermore, for each thermoelectric module 102, the thermal coupling of said thermoelectric module 102 to the first ring 103 is ensured via another of the thermal diffusers 105b, preferably this other of the thermal diffusers 105b extends, in the thermal insulation 101, in particular from the first ring 103 to come into contact with the module 102 thermoelectric. This third example embodiment is a functional alternative to the first and second example embodiments. Preferably, the thermal diffusers referenced 105a here each extend radially from the second ring 104, in particular towards the center of the second ring 104. Preferably, the thermal diffusers referenced 105b each extend here radially from the first ring 103, in particular towards a direction opposite to the center of the first ring 103. In FIG. 9, the third embodiment is such that the thermoelectric generator 100 comprises, in a non-limiting manner, twelve thermal diffusers 105a, 105b and six thermoelectric modules 102.

Preferably, for each thermal diffuser 105a, 105b in connection with one of the thermoelectric modules 102, this connection of the thermal diffuser 105a, 105b with the thermoelectric module 102 can:
- be a contact between the thermal diffuser 105a and the thermoelectric module 102, or
- preferably include, that is to say for example be provided by, a thermally conductive adhesive, or thermal paste such as silver paste, connecting the thermal diffuser 105a, 105b to the thermoelectric module 102 to improve the heat transfer between the thermoelectric module 102 and the heat diffuser 105a, 105b.

Preferably, each connection of one of the thermoelectric modules 102 with one of the rings, that is to say the first ring 103 or the second ring 104, can:
- be a contact between the corresponding ring and the thermoelectric module 102, or
- preferably include, that is to say for example be provided by, a thermally conductive adhesive, or thermal paste such as silver paste, connecting the thermoelectric module 102 to the corresponding ring to improve the thermal transfer between the thermoelectric module 102 and the corresponding ring.

In other words, a connection between two elements within the meaning of the present description can be ensured by a contact between these two elements or by a material such as a thermally conductive adhesive, or thermal paste such as silver paste, connecting these two elements.

Preferably, for each thermoelectric module 102 in connection with the first ring 103 or the second ring 104, this connection is made on a flat surface, or flat 123 (FIG. 2), of this first ring 103 or of this second ring 104.

Each thermal diffuser 105a, 105b can be based on a thermally conductive material such as, for example, steel or aluminum. In particular, each thermal diffuser 105a, 105b is made of steel or aluminum.

In particular, each thermal diffuser 105a, 105b can be made of a material having a thermal conductivity of between 20 Wm ^-1 ·K ^-1 and 400 Wm ^-1 ·K ^-1 .

Each thermal diffuser 105a, 105b can have, depending on its direction of extension between the first and second rings 103, 104, a dimension of between 5 mm and 19.5 cm. The preferred minimum dimension of 5 mm for each thermal diffuser 105a, 105b makes it possible to limit thermal leakage through the thermoelectric module 102 to which the thermal diffuser 105a, 105b is linked. The preferred maximum dimension of 19.5 cm for each thermal diffuser 105a, 105b makes it possible to ensure a sufficient supply of heat to the thermoelectric module 102 via the thermal diffuser 105a, 105b to which this thermoelectric module 102 is linked.

Preferably, each thermal diffuser 105a, 105b which extends from a ring chosen from one of the first and second rings 103, 104 can be a part independent of this ring and fixed to this ring, for example by screwing using screws. passing through this ring and screwed into the corresponding thermal diffuser. Even more preferentially, each thermal diffuser 105a, 105b which extends from one of the first and second rings 103, 104 can form a projection from the corresponding first ring 103 or the corresponding second ring 104. This projection can form, with a part (for example a thermal absorber as described below) of the corresponding first ring 103 or of the corresponding second ring 104, a one-piece piece: this allows better thermal conduction by eliminating the thermal contact resistance present in case of assembled independent parts. The elimination of the thermal contact resistance makes it possible to improve the temperature difference to which the thermoelectric modules 102 are subjected and therefore to improve the energy efficiency of the thermoelectric generator 100. Obtaining part of the first ring 103 or of the second ring 104 in one piece with one of the thermal diffusers can be achieved by casting or molding a corresponding one-piece part.

According to the examples represented in FIGS. 2, 4, 8 and 9, the thermoelectric modules 102 are six in number. Of course, this is not limiting in the sense that these thermoelectric modules 102 may be more or less numerous, in particular depending on their size, the size of the thermoelectric generator 100 and the diameter of the pipe 1000 on which the thermoelectric generator 100 is intended to be mounted. For example, the thermoelectric modules 102 are arranged in the thermoelectric generator 100 concentrically and at regular intervals.

Preferably, apart from the contribution of thermal energies to the thermoelectric modules 102, it is sought to limit the heat exchanges on either side of the thermal insulation 101 according to its thickness to limit the heat loss of the fluid circulating in the pipe 1000 in the configuration of use of the thermoelectric generator 100. In order to tend to limit such heat exchanges, the shape of the thermal diffusers 105a, 105b can be adapted to allow a satisfactory supply of thermal energy to the thermoelectric modules 102 while limiting, for each thermal diffuser 105a, 105b, the diffusion of this energy from the other side of the thermoelectric module 102 with which it is connected. To meet this need, each thermal diffuser 105a, 105b comprises, for example along its axis of extension (for example its longitudinal axis) between the first and second rings 103, 104, a first part 106 adopting the shape of a cone truncated and a second part 107 arranged in continuity with the truncated end of the truncated cone (FIGS. 2, 4 and 5). This second part 107 extending from the first part 106 so as to present a connecting face 107a (for example visible in FIG. 5) to one of the thermoelectric modules 102, said connecting face 107a presenting a surface of smaller dimensions or equal to a surface 102a of said thermoelectric module 102 with which the connecting face 107a is bonded. According to another formulation, each thermal diffuser 105a, 105b comprises a truncated cone delimiting its first part 106 in particular connected, if necessary, to the first ring 103 or to the second ring 104. This particular form of thermal diffusers 105a, 105b makes it possible to effectively concentrate thermal energy to the thermoelectric modules 102 while limiting the passage of this thermal energy to the other side of the thermoelectric modules 102.

Preferably, for each thermal diffuser 105a, 105b, the dimension of its second part 107 parallel to the axis of extension of said thermal diffuser 105a, 105b may be equal to 5 mm.

For example, the section of each thermal diffuser 105a, 105b at the truncated end of the truncated cone is of dimensions strictly greater than those of the face of the thermoelectric module 102 with which said thermal diffuser 105a, 105b is connected. In this case, for each thermal diffuser 105a, 105b, its second part 107 extends from its first part 106 to its connecting face 107a by progressively adapting its section so that the connecting face 107a of the second part 107 or as described above and linked to the corresponding thermoelectric module 102.

Preferably, the face of each thermoelectric module 102 in connection with one of the corresponding thermal diffusers 105a, 105b is in the form of a parallelogram. In this case, for each thermal diffuser 105a, 105, the second part 107 of this thermal diffuser 105a, 105b then comprises four bevels meeting to delimit the periphery of the connecting face 107a of this thermal diffuser 105a, 105b, preferably such so that the connecting face 107a connected to the corresponding thermoelectric module 102 is fully connected to the parallelogram-shaped face of this thermoelectric module 102. Furthermore, to optimize heat diffusion to the thermoelectric module 102 concerned, each connecting face 107a may have a surface area equal to the surface area of the parallelogram-shaped face of the thermoelectric module 102 with which this connecting face 107a is connected. . In other words, more generally, the second part 107 of each thermal diffuser 105a, 105b extends from the first part 106 of this thermal diffuser 105a, 105b by progressively adapting its section, taken orthogonally to the axis of extension of the thermal diffuser 105a, 105b between the first and second rings 103, 104, as far as the connecting face 107a of this thermal diffuser 105a, 105b, this connecting face 107a being integrally connected with the corresponding thermoelectric module 102.

Preferably, the thermal insulation 101 is formed by a thermally insulating material having a thermal conductivity of between 0.01 Wm ^-1 ·K ^-1 and 0.2 Wm ^-1 ·K ^-1 . This has the advantage of being very particularly suitable for ensuring suitable thermal insulation, preferably when the minimum thickness of the thermal insulation 101 between its internal circumference and its external circumference is between 7 mm and 21 cm.

Preferably, the material of thermal insulation 101 has a compressive strength strictly greater than 50 MPa and preferably less than or equal to 300 MPa. This allows it to be particularly suitable for submerged use of the 100 thermoelectric generator.

Preferably, the material forming the thermal insulator 101 may comprise a resin loaded with hollow balls. In other words, hollow balls can be dispersed in the resin which is then in the solid state to ensure the cohesion of the thermal insulator 101. For example, the resin can be an epoxy resin or a polyurethane resin. For example, the hollow balls can be glass balls, in particular silica balls. Such glass balls are particularly able to withstand the high pressures found in the seabed. According to another example, the hollow balls can be polymer balls able to deform according to the pressure, this being advantageous in underwater environments to absorb, that is to say resist, the isostatic pressure. Such hollow balls can each have: a diameter of between 1 μm and 100 μm, and a wall thickness separating the inside of the ball from the outside of the ball of between 200 nm and 5 μm. The polymer material may be polyimide, such as for example Kapton®, with a core-shell structure, the core of which is notably empty and the shell forms the wall of the corresponding ball.

It has been described previously that the aim is to limit the heat loss of the fluid circulating in the pipe 1000. For example, on an underwater production pipe making it possible to extract a petroleum product, the admissible heat loss (also called thermal reference) is between 80 W/m ² and 150 W/m ² on the average diameter of the pipe 1000 then made of steel. The average diameter corresponds to the average of the internal diameter of the pipe 1000 and the external diameter of the pipe 1000, such an average diameter is used as a reference value to give the reference heat loss of the pipe 1000. However, each thermoelectric module 102 present in the thermal insulation 101 locally forms a thermal bridge such that the thermal leaks are mostly localized in the thermoelectric modules 102. As a result, it is preferable for each thermoelectric module 102 to have a high thermal resistivity limiting thermal leakage through this thermoelectric module 102. To limit such thermal leaks through the thermoelectric modules 102, considering that the thermoelectric generator 100 has a central axis A1 (FIGS. 1 and 3), this central axis A1 of the thermoelectric generator 100 being surrounded by the thermal insulation 101, each thermoelectric module 102 has a thermal resistance greater than or equal to where N is the number of thermoelectric modules 102 of the thermoelectric generator 100, π is the number pi, R ₁ is the distance orthogonally separating the central axis A1 of the thermoelectric generator 100 with respect to an internal face 124 of the thermal insulation 101 ( represented by a dotted circle in FIG. 3 because it is not directly visible) proximal to the central axis A1 of the thermoelectric generator 100 (FIG. 3), R ₂ is the distance orthogonally separating the central axis A1 of the thermoelectric generator 100 with respect to a face 125 of the thermal insulator 101 distal from the central axis A1 of the thermoelectric generator 100 (FIG. 3), λ is the thermal conductivity of the thermally insulating material of, that is to say forming, the thermal insulator 101, H is the dimension of said thermoelectric module 102 (visible in FIG. 5) measured parallel to the central axis A1 of the thermoelectric generator 100, and ln is the natural logarithm. Preferably, the thermoelectric modules 102 each have a dimension H measured parallel to the central axis A1 of the thermoelectric generator 100 such that all the dimensions H have the same value. In other words, R ₁ represents in particular the internal radius of the thermal insulator 101 and R ₂ represents in particular the external radius of the thermal insulator 101. Preferably, in order to maximize the electrical power generated by the thermoelectric modules 102, the thermal resistance of each of the thermoelectric modules 102 will be the closest to, or even equal to, .

According to a particular embodiment making it possible to facilitate the assembly of the thermoelectric generator 100 to obtain the configuration of use, the first ring 103 can comprise a plurality of first absorbers 108 (for example 3 in number in FIGS. 1 to 4, 8 and 9 ) thermals linked together. According to this particular embodiment, the second ring 104 may comprise a plurality of second thermal absorbers 109 (for example 3 in number in FIGS. 1 to 4, 8 and 9) interconnected. In this case, each thermoelectric module 102 is thermally coupled, on the one hand, to one of the first thermal absorbers 108 so as to ensure the thermal coupling of this thermoelectric module 102 to the first ring 103 and, on the other hand, to one of the second thermal absorbers 109 so as to ensure the thermal coupling of this thermoelectric module 102 to the second ring 104, if necessary by connection with the corresponding thermal absorber or by means of a corresponding thermal diffuser. According to this particular embodiment, the thermoelectric generator 100 can be formed by assembling several elementary devices 110 each comprising a thermally insulating element 111, one of the first thermal absorbers 108 and one of the second thermal absorbers 109 separated by the thermally insulating element 111 forming, within the assembled thermoelectric generator 100, a portion of the thermal insulation 101 (FIGS. 1 to 4 and 8 to 11).

In particular, the cutting of the thermoelectric generator 100 into several elementary devices 110 facilitates the assembly of the thermoelectric generator 100 on the pipe 1000. where it should be located.

The function of the first and second thermal absorbers 108, 109 being to capture, that is to say harvest, heat, these first and second thermal absorbers 108, 109 are preferably each based on, or made of, material thermally conductive such as steel or aluminum. Preferably, each thermal absorber, whether it is one of the first thermal absorbers 108 or one of the second thermal absorbers 109, can be made of a material having a thermal conductivity of between 20 Wm ^-1 ·K ^-1 and 400 Wm ^-1 . K ^-1 to adequately perform its heat recovery function.

According to the particular embodiment described above, the first thermal absorbers 108 can be assembled two by two using one or more flanges and/or be fixed two by two by gluing to form the first ring 103. the same applies to the second thermal absorbers 109 which can be assembled in pairs using one or more flanges and/or be fixed in pairs by gluing to form the second ring 104. In this case, the assembly of the thermoelectric generator 100 can allow the thermoelectric generator 100 to be clamped directly to pipe 1000.

Thus, it is understood that each of the first thermal absorbers 108 preferably has a curved shape to form part of the first ring 103. Furthermore, each of the second thermal absorbers 109 preferably has a curved shape to form part of the second ring 104.

Within the thermoelectric generator 100, the assembly of the first thermal absorbers 108 can be such that the first ring 103 is entirely thermally conductive. The same goes for the assembly of the second thermal absorbers 109 which can form the second ring 104 which is entirely thermally conductive.

The elementary devices 110 can each form a quarter, a half or a third of the first ring 103, of the second ring 104 and of the thermal insulation 101. More generally, the elementary devices 110 can have dimensions such that each elementary device 110 comprises at least one thermoelectric module 102 and that the assembly of several of these elementary devices 110 can form the thermoelectric generator 100. Thus, each elementary device 110 can comprise between one thermoelectric module 102 and 50% of the thermoelectric modules 102 of the thermoelectric generator 100.

For example, each elementary device 110 can form from 1/5 to 1/10 of the thermoelectric generator 100.

Alternatively, in particular when the elementary devices 110 are glued, in particular two by two, to assemble the thermoelectric generator 100, the glue used may be thermally insulating to avoid the formation of a thermal bridge connecting the first and second rings 103, 104 to the junction between two elementary devices 110. Thus, the first ring 103 can be partially thermally conductive, the thermal conduction of this first ring 103 is then interrupted locally in each bonding zone of two first adjacent thermal absorbers 108: the first ring 103 notably remains predominantly thermally conductive. Furthermore, the second ring 104 formed may be partially thermally conductive, the thermal conduction of this second ring 104 is then interrupted locally in each bonding zone of two adjacent second thermal absorbers 109: the second ring 104 notably remains predominantly thermally conductive.

Preferably, the glue used to glue the elementary devices 110 together is, in its solid bonding state, a material identical to the material of the thermally insulating elements 111. However, any other type of glue, for example a resin, making it possible to ensure the function of bonding the elementary devices 110 together, while avoiding the formation of thermal bridges connecting the first and second rings 103, 104, can be used. Bonding also has the advantage of avoiding the infiltration of sea water, for example, which could form a thermal bridge.

In this sense, it follows from what has been described above that the invention also relates to the elementary device 110, for example as seen in Figures 10 and 11, for the manufacture of the thermoelectric generator 100 for pipe 1000 in particular such as previously described, this elementary device 110 comprising: the first thermal absorber 108 configured to partially surround the pipe 1000 and preferably to cooperate (that is to say in particular come into contact) with a part of the pipe 1000; the second thermal absorber 109 arranged at a distance from the first thermal absorber 108; the thermally insulating element 111 connecting the first thermal absorber 108 to the second thermal absorber 109. Preferably, the first thermal absorber 108 is fixed by gluing to the thermally insulating element 111 and the second thermal absorber 109 is fixed by gluing to the thermally insulating element 111. Furthermore, the elementary device 110 comprises at least one thermoelectric module 102 arranged in the thermally insulating element 111 between the first thermal absorber 108 and the second thermal absorber 109, the thermoelectric module 102 being thermally coupled to the first absorber 108 and thermally coupled to the second thermal absorber 109 with a view to respectively performing the thermal coupling of the thermoelectric module 102 to the first ring 103 and the thermal coupling of the thermoelectric module 102 to the second ring 104. In the example represented in FIG. 11, the elementary device 110 comprises two modules 102 thermoelectrics, this number being able to be adapted according to the needs.

In general, the elementary device 110 is such that the first heat absorber 108 may comprise a convex face 108a oriented towards a concave face 109a of the second absorber 109 (FIG. 11). In particular, the thermally insulating element 111 connects the convex face 108a of the first thermal absorber 108 to the concave face 109a of the second thermal absorber 109.

For example, the thermally insulating element 111 of the elementary device 110 extends radially from the first thermal absorber 108, in particular from the convex face 108a of this first thermal absorber 108, to the second thermal absorber 109, in particular at its concave face 109a .

Of course, in relation to what has been described above, the elementary device 110 may comprise, in particular for each thermoelectric module 102:
- the thermal diffuser 105a extending in the thermally insulating element 111, the thermal coupling of the thermoelectric module 102 to the first thermal absorber 108 being ensured by means of the thermal diffuser 105a, the thermoelectric module 102 being in connection with the second absorber thermal 109 (Figure 8), this connection can be a contact between the thermoelectric module 102 and the second thermal absorber 109 or be ensured by glue, or an adhesive, thermally conductive, or thermal paste for example paste of silver, connecting the thermoelectric module 102 to the second thermal absorber 109,
- the thermal diffuser 105a and the additional thermal diffuser 105b each extending into the thermally insulating element 111, the thermal coupling of the thermoelectric module 102 to the first thermal absorber 108 being ensured by means of the additional thermal diffuser 105b and the thermal coupling from the thermoelectric module 102 to the second thermal absorber 109 being provided via the thermal diffuser 105a (FIG. 9), or
- the thermal diffuser 105a extending in the thermally insulating element 111, the thermal coupling of the thermoelectric module 102 to the second thermal absorber 109 being ensured by means of the thermal diffuser 105a, the thermoelectric module 102 being in connection with the first absorber 108 thermal, this connection can be a contact between the thermoelectric module 102 and the first thermal absorber 108 or be ensured by glue, or an adhesive, thermally conductive, or even thermal paste such as silver paste, connecting the thermoelectric module 102 to the first thermal absorber 108 (FIG. 11).

In general, the thermal coupling of each thermoelectric module 102 to, where appropriate, first ring 103, second ring 104, first absorber 108 or second absorber 109, ensured via the intermediary of the or one of the diffusers 105a, 105b corresponding thermal may be such that this thermal diffuser 105a, 105b is:
- on the one hand, in conjunction with this thermoelectric module 102 in the manner described above and
- on the other hand, in connection with, where appropriate, the first ring 103, the second ring 104, the first absorber 108 or the second absorber 109, for example by screwing, or alternatively in connection by continuity of material with at least a part of the corresponding first ring 103, second ring 104, first absorber 108 or second absorber 109 so as to form a corresponding one-piece piece.

Since the thermoelectric generator 100 is intended to be mounted on a pipe 1000, in particular around the latter, it may comprise, or be associated with, a clamping system, also called a flange. This clamping system is configured to fix the thermoelectric generator 100 to the pipe 1000. For example, the thermoelectric generator 100 can be clamped by bonding its elementary devices 110 together and/or by using one or more hollow members through which the pipe 1000 passes. Each hollow member can be a thermally insulating member 118 (FIGS. 6 and 7) as described below. Each hollow member can then cooperate with the thermoelectric generator 100, for example when the hollow member is tightened by a clamp 121 towards the pipe 1000 that this clamp 121 surrounds, so as to urge the thermoelectric generator 100 towards the pipe. 1000 to maintain the position of the thermoelectric generator 100 with respect to the pipe 1000. In other words, the thermoelectric generator 100 can be mounted on the pipe 1000 by any suitable clamping system allowing it to be maintained with respect to the pipe 1000.

Preferably, the first ring 103 comprises two opposite flanges 114, 115 (FIGS. 1 to 5). The height of each flange 114, 115, measured from the face of the first ring 103 in contact with the thermal insulation 101 and in particular orthogonal to the axis A1, can be between 5 mm and 10 mm. The width of each flange 114, 115, in particular measured parallel to the axis A1, can be between 5 mm and 10 mm. The two collars 114, 115 are opposite along the width, that is to say the transverse dimension, of the first ring 103. In particular, each collar 114, 115 extends from the face of the first ring 103 in contact with the thermal insulation 101 and each collar 114, 115 is at a distance from the thermal insulation 101, this distance can be between 2 cm and 7.5 cm. Thus, the first ring 103 is therefore wider than the second ring 104. Each collar 114, 115 facilitates the assembly of the elementary devices 110 to form the corresponding thermoelectric generator 100 and/or the assembly of two adjacent thermoelectric generators 100 in order to form a sheath as described below. The flanges 114, 115 can be used to clamp the first ring 103 with respect to the pipe 1000, in particular these flanges 114, 115 can each be inserted into a corresponding hollow member as described and tightened by a corresponding clamp 121. For example, two adjacent thermoelectric generators 100 can be assembled by an assembly device comprising a thermally insulating member 118, preferably in the shape of a crown, and a clamping collar 121 tightening the thermally insulating member 118 to stress the first two rings 103, preferably the first thermal absorbers 108, of these adjacent thermoelectric generators 100 towards, or against, the pipe 1000 with a view to maintaining the two thermoelectric generators 100 with respect to the pipe 1000 and, if necessary, maintaining the elementary devices 110 forming each of the thermoelectric generators between them.

Within the framework of the elementary device 110 making it possible to form the thermoelectric generator 100 with two flanges 114, 115, the first thermal absorber 108 comprises two side flanges 116, 117 (FIGS. 10 and 11) each located at a distance from the thermally insulating element 111 . Each lateral flange 116, 117 is intended to form a corresponding part respectively of the flange 114 and of the flange 115. In particular, each lateral flange 116, 117 extends radially from a face of the first thermal absorber 108 in contact with the element 111 thermally insulating.

It follows from all that has been described above that the invention also relates to an installation 2000 for the transport of the fluid (FIGS. 6 and 7), preferably petroleum, comprising the pipe 1000 for transport, preferably under navy, fluid. This installation 2000 comprises at least one thermoelectric generator 100 as described preferably mounted on the pipe 1000. In particular, the thermoelectric generator 100 surrounds the pipe 1000 preferably around the longitudinal axis of the pipe 1000. For example, the thermoelectric generator 100 forms a sleeve whose first ring 103 is crossed by the pipe 1000. Thus, the generation of current by the thermoelectric generator 100 can be ensured using a diffusion of a first thermal energy, from the fluid transported in the pipe 1000, to the thermoelectric modules 102 and a diffusion of a second thermal energy, from the environment outside the pipe 1000 and the thermoelectric generator 100, to the thermoelectric modules 102. The advantage of such an installation 2000 is that it ensures, in addition to the transport of the fluid, an efficient current generation while limiting the heat losses, through the thermoelectric generator 100, of the fluid during its passage in the pipe 1000 .

To meet a need to increase the electrical power generated and to improve the thermal insulation of the pipe 1000, it is preferred that the installation include a sheath 2001. This sheath 2001 is configured to thermally insulate the pipe 1000 and to generate electric current by thermoelectric effect. To perform these functions of thermal insulation and current generation, the sheath 2001 comprises a plurality of thermoelectric generators 100 as described each surrounding the pipe 1000 and preferably interconnected, for example in the manner illustrated in Figures 6 and 7 where are represented five thermoelectric generators 100 placed end to end to form the sheath 2001. Thus, the thermoelectric modules 102 of the thermoelectric generators of the sheath 2001 each participate in the generation of the electric current by the sheath 2001, and the thermal insulators 101 of the thermoelectric generators 100 of the sheath 2001 participate in thermally insulating the pipe 1000 in particular with respect to the environment in which it is placed. In this case, the thermoelectric modules 102 of the various thermoelectric generators 100 can all be electrically connected in series to add the voltages generated and collect all of the electrical power generated. To make such an electrical connection in series, it is possible to use suitable electrical connectors connecting the thermoelectric modules 102 of the same thermoelectric generator to each other and, if necessary, electrically connecting in series the thermoelectric modules 102 of the thermoelectric generators 100 . Of course, in the context of an underwater application, care must be taken to protect the electrical connectors from the marine environment, for example by coating them in a waterproof resin during or after the assembly of the elementary devices 110 and/or 100 thermoelectric generators to be electrically connected together.

Preferably, the sheath 2001 is such that thermoelectric generators 100 are arranged successively along the pipe 1000 and that for any pair of adjacent thermoelectric generators 100a, 100b (FIGS. 6 and 7):
- the first rings 103a, 103b of the thermoelectric generators 100a, 100b of said pair of adjacent thermoelectric generators 100a, 100b each comprise a collar 114a, 115b, preferably forming a lateral end of the corresponding ring 103a, 103b and extending radially compared to pipe 1000,
- said flanges 114a, 115b are connected for example by gluing together or by contact with each other,
- the sheath 2001 comprises the thermally insulating member 118, in particular annular, arranged between the thermoelectric generators 100a, 100b of said pair of adjacent thermoelectric generators 100a, 100b, the thermally insulating member 118 comprising an annular groove 119, in particular located at the circumference internal part of the thermally insulating member 118, into which said collars 114a, 115b are inserted.
In other words, the thermally insulating member 118 straddles the first rings 103a, 103b of two thermoelectric generators 100a, 100b which it connects and comes in particular into contact with, or is glued to, the thermal insulators 101a, 101b of these two generators 100a , 100b adjacent thermoelectrics in order to form a continuous thermal insulation of the pipe 1000 over the entire length of the sheath 2001. The bonding of the thermally insulating member 118 to the thermal insulators 101a, 101b of these two adjacent thermoelectric generators 100a, 100b is preferred to avoid infiltration, for example of water, and to generate a thermal leak or corrosion. Such bonding may be identical to that assembling the elementary devices 110 of a same thermoelectric generator 100. Thus, the role of the flanges 114a, 115b is to allow assembly, in cooperation with the thermally insulating member 118, ensuring continuity of the thermal insulation of the sheath 2001 between the two adjacent thermoelectric generators 100a, 100b.

Preferably, for any pair of adjacent thermoelectric generators 100a, 100b (FIGS. 6 and 7), the sheath 2001 comprises a clamping collar 121, said clamping collar 121 enclosing the thermally insulating member 118, in particular at its outer circumference, arranged between the thermoelectric generators 100a, 100b of said pair of adjacent thermoelectric generators 100a, 100b. In particular, the clamping collar 121 surrounds the thermally insulating member 118 and the pipe 1000. This has the advantage that the clamping collar 121 encloses the corresponding thermally insulating member 118 in such a way that this results in the maintenance of the generators 100a, 100b adjacent thermoelectrics of the corresponding couple between them and preferably with respect to the pipe 1000.

The thermally insulating member 118 can be formed in several parts assembled together, for example by gluing and/or by the corresponding clamp 118, these parts possibly being two, three or four in number. The thermally insulating member 118 may include a cavity in which the clamp 121 mentioned above is inserted.

Preferably, the thermally insulating member 118 is based on, or is formed by, the same material as that of the thermal insulator 101. The thermally insulating member 118 can therefore have the same characteristics as the thermal insulator 101.

The thickness of each thermally insulating member 118 around the pipe 1000 can be between 7 mm and 240 mm in order to ensure satisfactory thermal insulation avoiding the formation of a thermal bridge and in order to participate in tightening, towards the pipe 1000, adjacent thermoelectric generators 100a, 100b which it connects. The thermally insulating member 118 can extend as far as the second rings 104 of the adjacent thermoelectric generators 100a, 100b which it connects.

For example, the thickness of each thermally insulating member 118 is such that this thermally insulating member 118 has an outer diameter corresponding to the outer diameter of the thermoelectric generators 100 to facilitate the formation of the sheath 2001 and the handling of this sheath 2001.

It follows from what has been described above that the use of elementary devices 110 is very particularly advantageous because their assembly, in particular with the aid of thermally insulating members 118 effectively makes it possible to surround the pipe 1000 to insulate it thermally from its external environment.

Preferably, it is sought to limit the effective exchange surface between the two heat sources in order to limit the effects of thermal bridges, for this this effective exchange surface is preferably between 0.2% and 5% of the surface of the sheath 2001 in connection with, that is to say the surface of the sheath 2001 oriented towards and opposite, the pipe 1000. The effective exchange surface is defined as being the sum of the surfaces of the modules 102 thermoelectric in connection with the heat diffusers 105a, 105b, or in connection with the heat diffusers 105a and the first or second ring 103, 104, of an installation as described.

The installation 2000 may comprise one or more electronic devices 2002 (FIGS. 6 and 7), such as a sensor or an actuator, electrically powered by the thermoelectric generator(s) 100 assembled to form the sheath 2001. Thus, the recovery of energy using one or more thermoelectric generators 100 can be based on the conversion of waste heat between the fluid and, where appropriate, sea water to make the electronic device(s) 2002 autonomous: this presents the advantage of not having to pull, for example from the surface of the sea, electrical supply cables of the electronic device(s) 2002 which can be placed at depths which can reach 2000 m.

For example, the thermoelectric generator 100 forms a crown having: an internal circumference for example of diameter between 10 cm and 60 cm, depending on the diameter of the pipe 1000 on which it is mounted or must be mounted, an external circumference of diameter included between 11.7 cm and 87 cm. The transverse dimension of the second ring 104 can be between 5 cm and 14 cm. The transverse dimension of the thermal insulator 101, measured parallel to the transverse dimension of the first ring 103, can be between 5 cm and 14 cm. The transverse dimension of the first ring 103 can be between 10 cm and 22 cm. The height of each of the thermoelectric modules 102, measured radially to the first ring 103, can be between 2 mm and 15 mm. The thickness of each of the first and second rings 103, 104 can be adapted to ensure good resistance to compression, in particular with respect to the underwater environment, for example this thickness can be between 5 mm and 30 mm.

There is now described a particular embodiment for which the pipe 1000 has an outside diameter of 220 mm. According to this particular example, the thermoelectric generator 100 is such that: the thickness of the thermal insulation 101 between the first and second rings 103, 104 is 95 mm; the thermoelectric generator 100 comprises six thermoelectric modules; the thermoelectric generator 100 has a maximum dimension, parallel to the longitudinal axis of the pipeline, of 20 cm. According to this particular example, the thermoelectric modules 102 are of the type, that is to say they comprise bismuth and antimony telluride conventionally used for operating temperatures between 0° C. and 200° C., of course, other materials forming part of the composition of the thermoelectric modules 102 can also be used, such as lead telluride, silicides, skutterudites or perovskites. According to this particular example, each thermoelectric module 102 comprises 34 legs made of thermoelectric material electrically connected in series and thermally in parallel, each leg having a height of 7 mm and a section of 2 mm by 2 mm orthogonal to its height. Of course, the dimensions of the thermoelectric modules are adapted to the particular example according to the electrical generation constraints and the thermal insulation constraints of the pipe: these thermoelectric modules can therefore be adapted according to the needs. According to this particular example, the thermal insulator 101 comprises an epoxy resin. This particular example made it possible to generate an electrical power of 500 mW per thermoelectric generator 100 for an external heat source temperature in contact with the second ring 104 of 4° C. and for a temperature of the fluid transported by the pipe of 70° C. Thus, by forming a sheath comprising ten thermoelectric generators 100 according to this particular example as represented in FIGS. 6 and 7, it is possible to generate an electrical power of 5 W by connecting in series all the thermoelectric modules 102 of these generators 100 thermoelectrics.

The present invention finds an industrial application in the field of current generation, preferably for powering autonomous electronic devices, such as one or more sensors and/or one or more actuators, from a pipeline 1000 for transporting fluid. In particular, the pipeline 1000 can be a pipeline, preferably for underwater production, that is to say a pipeline for oil extraction such as, for example, oil or gas extraction.

Claims (15)

Thermoelectric generator (100) for a pipe (1000), said thermoelectric generator (100) comprising a thermal insulator (101) and thermoelectric modules (102), characterized in that:

• the thermoelectric generator (100) comprises a first ring (103) at least partially thermally conductive, the first ring (103) being intended to surround the pipe (1000),
• the thermoelectric generator (100) comprises a second ring (104) at least partially thermally conductive, the second ring (104) surrounding the first ring (103),
• the thermal insulator (101) connects the first ring (103) to the second ring (104),
• each thermoelectric module (102) is placed in the thermal insulation (101),
• each thermoelectric module (102) is thermally coupled to the first ring (103) and each thermoelectric module (102) is thermally coupled to the second ring (104).

Thermoelectric generator (100) according to Claim 1, characterized in that it comprises thermal diffusers (105a, 105b) arranged in the thermal insulation (101), each thermoelectric module (102) being thermally coupled to one of the first and second rings (103, 104) through one of the thermal diffusers (105a, 105b). Thermoelectric generator (100) according to the preceding claim, characterized in that each thermal diffuser (105a, 105b) comprises:

• a first part (106) adopting the shape of a truncated cone,
• a second part (107) arranged in continuity with the truncated end of the truncated cone,

said second part (107) extending from said first part (106) so as to present a face (107a) for connection to one of the thermoelectric modules (102), said face (107a) for connection presenting a surface of dimensions less than or equal to a surface of said thermoelectric module (102) with which the connecting face (107a) is bonded. Thermoelectric generator (100) according to any one of Claims 2 to 3, characterized in that, for each thermoelectric module (102):

• the thermal coupling of said thermoelectric module (102) to the second ring (104) is ensured via one of the thermal diffusers (105a), or
• the thermal coupling of said thermoelectric module (102) to the first ring (103) is ensured via one of the thermal diffusers (105a), or
• the thermal coupling of said thermoelectric module (102) to the second ring (104) is ensured via one of the thermal diffusers (105a) and the thermal coupling of said thermoelectric module (102) to the first ring (103) is ensured by through another of the thermal diffusers (105b).

Thermoelectric generator (100) according to any one of the preceding claims, characterized in that:

• the first ring (103) includes a plurality of interconnected first thermal absorbers (108),
• the second ring (104) comprises a plurality of second heat absorbers (109) interconnected,
• each thermoelectric module (102) is thermally coupled, on the one hand, to one of the first thermal absorbers (108) and, on the other hand, to one of the second thermal absorbers (109).

Thermoelectric generator (100) according to any one of the preceding claims, characterized in that the thermal insulation (101) is formed by a thermally insulating material having a thermal conductivity of between 0.01 Wm ^-1 .K ^-1 and 0 .2 Wm ^-1 .K ^-1 . Thermoelectric generator (100) according to any one of the preceding claims, characterized in that the thermal insulation (101) has a compressive strength strictly greater than 50 MPa. Thermoelectric generator (100) according to any one of the preceding claims, characterized in that it has a central axis (A1) surrounded by the thermal insulation (101), and in that each thermoelectric module (102) has a resistance thermal greater than or equal to where N is the number of thermoelectric modules (102), R ₁ is the distance orthogonally separating the central axis (A1) with respect to an internal face (124) of the thermal insulator (101) proximal to the central axis ( A1), R ₂ is the distance orthogonally separating the central axis (A1) with respect to a face (125) of the thermal insulation (101) distal to the central axis, λ is the thermal conductivity of the thermally insulating material of the thermal insulator (101), and H is the dimension of said thermoelectric module (102) measured parallel to the central axis (A1). Thermoelectric generator (100) according to any one of the preceding claims, characterized in that the first ring (103) comprises two opposite flanges (114, 115), the two flanges (114, 115) being at a distance from the thermal insulation (101). Installation (2000) for transporting a fluid, preferably petroleum, comprising a pipeline (1000) for transporting the fluid, preferably underwater, characterized in that it comprises at least one thermoelectric generator (100) according to any preceding claim, said thermoelectric generator (100) surrounding the pipe (1000). Installation (2000) according to the preceding claim, characterized in that it comprises a sheath (2001) configured to thermally insulate the pipe (1000) and to generate electric current by thermoelectric effect, the sheath (2001) comprising a plurality of generators (100) thermoelectric each surrounding the pipe (1000). Installation (2000) according to the preceding claim, characterized in that the thermoelectric generators (100) are arranged successively along the pipe (1000), and in that, for any pair of adjacent thermoelectric generators (100a, 100b):

• the first rings (103a, 103b) of the thermoelectric generators (100a, 100b) of said pair each comprise a flange (114a, 115b),
• said flanges (114a, 115b) are connected,
• the sheath (2001) comprises an annular thermally insulating member (118) arranged between the thermoelectric generators (100a, 100b) of said pair, the thermally insulating member (118) comprising an annular groove (119) in which said flanges (114a) are inserted , 115b).

Installation (2000) according to the preceding claim, characterized in that, for any pair of adjacent thermoelectric generators (100a, 100b), the sheath (2001) comprises a clamping collar (121), the said clamping collar (121) clamping the thermally insulating member (118) arranged between the thermoelectric generators (100a, 100b) of said pair of adjacent thermoelectric generators (100a, 100b). Elementary device (110) for manufacturing a thermoelectric generator (100) for a pipe (1000), characterized in that it comprises:

• a first heat absorber (108) configured to partially surround the pipe (1000) and preferably to cooperate with part of the pipe (1000),
• a second thermal absorber (109) arranged at a distance from the first thermal absorber (108),
• a thermally insulating element (111) connecting the first thermal absorber (108) to the second thermal absorber (109),
• at least one thermoelectric module (102) arranged in the thermally insulating element (111) between the first thermal absorber (108) and the second thermal absorber (109), the thermoelectric module (102) being thermally coupled to the first absorber (108) thermal and thermally coupled to the second thermal absorber (109).

Elementary device (110) according to the preceding claim, characterized in that it comprises:

• a thermal diffuser (105a) extending in the thermally insulating element (111), the thermal coupling of the thermoelectric module (102) to the first thermal absorber (108) being ensured via the intermediary of the thermal diffuser (105a), the module (102) being connected to the second thermal absorber (109), or

• a thermal diffuser (105a) and an additional thermal diffuser (105b) each extending in the thermally insulating element (111), the thermal coupling of the thermoelectric module (102) to the first thermal absorber (108) being provided by the intermediary of the additional thermal diffuser (105b) and the thermal coupling of the thermoelectric module (102) to the second thermal absorber (109) being ensured via the thermal diffuser (105a), or
• a thermal diffuser (105a) extending in the thermally insulating element (111), the thermal coupling of the thermoelectric module (102) to the second thermal absorber (109) being ensured via the intermediary of the thermal diffuser (105a), the module (102) thermoelectric being in connection with the first absorber (108) heat.