Fluid circulation device, installation and method using such a device

Description

[0001] The invention relates to a fluid circulation device as well as an installation and a method using such a device.

[0002] The invention relates more particularly to a fluid circulation device, especially for a refrigerator or cryogenic liquefier, comprising a housing sealed against the outside of the device and containing an electrical machine such as an electric motor or an alternator, the device comprising a cycle gas circuit subjecting the cycle gas to a thermodynamic change between a minimum pressure and a maximum pressure when the device is in operation, the device comprising at least one cycle gas drive element in the circuit such as a compressor wheel, said drive element being rotationally coupled to the electrical machine,the device comprising an electrical junction box sealed against the outside of the device and through which passes electrical circuitry having a first end connected to the electrical machine and a second end connected to at least one electrical fitting opening outside the junction box and located outside the casing.

[0003] The invention relates in particular to a cooling system for an electrical junction box of an electric motor by a cycle gas flow.

[0004] It may indeed be necessary to cool the electrical supply enclosure (junction box) of an electric motor or turbomachine.

[0005] This junction box is often located away from the gas circulation or the water radiator cooling the central part of the engine or associated turbomachine.

[0006] In known solutions, this enclosure is cooled by natural convection, by conduction through the junction box walls. Furthermore, heat management is achieved by sizing the junction box and increasing its surface area with ambient temperature, as well as by increasing the diameter of the cables and the size of the electrical connectors or plugs. These measures increase the overall size of the junction box, its weight, its manufacturing cost, and the risk of leakage.

[0007] Furthermore, due to its ability to withstand pressure, the wall thickness of such a housing limits its cooling by conduction. JP H10 292948 A discloses a fluid circulation device comprising a housing sealed against the outside of the device and containing an electrical machine such as an electric motor, the device comprising a cycle gas circuit subjecting the cycle gas to a thermodynamic change between a minimum pressure and a maximum pressure when the device is in operation, the device comprising at least one cycle gas drive element in the circuit such as a compressor wheel, said drive element being rotationally coupled to the electrical machine, the device comprising a cycle gas supply line, the fluid circuit comprising a cycle gas return line having a first end communicating with the inside of the housing and a second end connected to the circuit.

[0008] One aim of the present invention is to overcome all or part of the disadvantages of the prior art noted above.

[0009] To this end, the device according to the invention, as defined in claim 1, comprises a pressurized cycle gas supply line having a first end connected to a portion of the circuit in which the cycle gas is at a pressure greater than the minimum pressure and a second end communicating with the inside of the junction box, the junction box comprising a communication passage with the inside of the housing, the fluid circuit comprising a cycle gas return line having a first end communicating with the inside of the housing and a second end connected to the circuit, the supply line, the passage and the return line being configured to take a fraction of the cycle gas flowing in the circuit to circulate it in the junction box in order to cool the latter before returning to the circuit.

[0010] Furthermore, embodiments of the invention may include one or more of the following characteristics: The first end of the supply line is connected to the circuit downstream of an outlet of a drive unit; the second end of the supply line opens into the housing and / or the junction box; the first end of the return line opens into the housing and / or the junction box; the second end of the return line is connected to the circuit upstream of an inlet of a drive unit; the device includes a flow control device for the fluid circulating in the supply line; the flow control device includes at least one of the following: a valve, a calibrated orifice; the fluid circuit includes a fluid flow cooling device such as a heat exchanger disposed between an outlet of the circulating unit and the first end of the bypass line; the passage and a first end of the return line are located at opposite ends of the junction box.The electrical circuitry that passes through the junction box includes a set of electrical cable(s), the passage including a communication opening between the inside of the junction box and the inside of the housing and through which the set of cable(s) extends, the device includes at least two separate housings each containing an electrical machine for driving respective drive elements, each electrical machine being provided with a respective electrical junction box communicating with the housing via a passage, the device including at least two pressurized cycle gas supply lines each comprising a first end connected to a portion of the circuit in which the cycle gas is at a pressure greater than the minimum pressure and a second end communicating with the inside of a corresponding junction box,the first end of a first supply line to the casing of a first electrical machine is connected to the fluid circuit downstream of the outlet of a first drive element, the device comprising a transfer line having a first end connected to the casing of the first electrical machine and a second end opening into the junction box of the second electrical machine, the device comprising a return line having a first end communicating with the second casing and a second end connected to the circuit, the first supply line, the transfer line, the passages and the return line being configured to take a fraction of the fluid flow in the fluid circuit to circulate it in series through the junction boxes in order to cool them before returning to the circuit,The device comprises two supply lines, the first ends of which are connected to the circuit and the second ends of which communicate in parallel respectively with the two junction boxes and / or with the two housings; the first ends of the two supply lines are connected to the same portion of the circuit.

[0011] The invention also relates to a refrigeration and / or liquefaction installation comprising a refrigerator having a working circuit of a cycle gas, said circuit comprising, arranged in series, at least one cycle gas compression stage, at least one cycle gas cooling element, at least one cycle gas expansion stage and at least one cycle gas heating element, the installation comprising a circulation device according to any one of the above or below characteristics in which the drive element comprises a compressor wheel forming a compression stage.

[0012] Depending on other possible characteristics: at least one cycle gas heating element includes a heat exchanger in heat exchange with an element to be cooled, for example a fluid stream, the cycle gas includes at least one of: nitrogen, helium, hydrogen, argon, neon.

[0013] The invention, as defined in claim 18, also relates to a method for cooling an electrical junction box of an electric motor of a circulation device conforming to any of the above or below characteristics or of a aforementioned installation, the method comprising a step of taking a fraction of the fluid flow in the fluid circuit and circulating this fraction of fluid in the junction box in order to cool the latter and then a step of returning this fraction of fluid to the fluid circuit. Depending on other possible characteristics:

[0014] The invention may also relate to any alternative device or method comprising any combination of the above or below features within the scope of the claims.

[0015] Other features and advantages will become apparent upon reading the description below, which refers to the figures in which: [ Fig.1 ] represents a schematic and partial view illustrating a first example of the possible structure and operation of a device according to the invention, [ Fig.2 ] represents a schematic and partial view illustrating a first example of the possible structure and operation of an installation according to the invention, [ Fig.3 ] represents a schematic and partial view illustrating a second example of the possible structure and operation of an installation according to the invention, [ Fig.4 ] represents a schematic and partial cross-sectional view illustrating a first example of a possible embodiment of a detail of the junction box of the device or installation according to the invention, [ Fig.5 ] represents a schematic and partial view illustrating a second example of the possible structure and operation of a device according to the invention, [ Fig.6 ] represents a schematic and partial cross-sectional view illustrating a second possible embodiment of a detail of the junction box of the device or installation according to the invention, [ Fig.7 ] represents a schematic and partial cross-sectional view illustrating a third possible embodiment of a detail of the junction box of the device or installation according to the invention, [ Fig.8 ] represents a schematic and partial view illustrating a third example of the possible structure and operation of an installation according to the invention.

[0016] The fluid circulation device 1 illustrated as an example in the [ Fig.1 It is preferably intended for use in a cryogenic refrigerator or liquefier using a cycle gas. Of course, it could be used in other devices such as a compression apparatus (in particular, a non-cryogenic compressor).

[0017] Device 1 comprises a housing 2 sealed against the outside of the device and containing an electric motor 3, at least one fluid drive element 4 such as a compressor wheel mounted on a shaft 20 driven in rotation by the electric motor 3 to form a compression stage for the cycle gas. Device 1 includes a cycle gas circuit 5 and includes a downstream portion connected to an outlet of the drive element 4 (for example, the outlet of the compression stage).

[0018] Device 1 includes a sealed electrical junction box 6, which is sealed against the outside of the device and through which electrical circuitry 8 passes. The junction box 6 is, for example, mounted on or integral with the housing 2. For example, the junction box 6 is a separate housing from the housing 2 and communicates with the housing 2 via one or more passages or openings. Similarly, at least a portion of the walls delimiting the junction box 8 may be common to and coincide with a portion of at least one wall delimiting the housing 2.

[0019] The electrical circuitry 8 has one end connected to the motor 3 (via a passage 9 through the housing 6 and casing 2 or other) and a second end connected to at least one electrical connector 7 opening outside the junction box 6. The electrical connector 7 is typically located outside the casing 2 (and the device 1 if applicable).

[0020] As illustrated, the electrical circuitry 8 which passes through the junction box 6 may include a set of electrical cable(s). These cables may be connected to at least one fitting 7, for example of the male type, which is mounted and protrudes, for example, on a wall or cover which seals the box 6 (for example, via a screw or stud fixing assembly and a sealing system, see [ Fig.4 For example, the fitting(s) 7 are surrounded by a protective wall. The fitting 7 thus forms an electrical junction which is external to the device 1 and in particular at ambient temperature, while the inside of the junction box 6 contains an atmosphere protected from the outside, for example a gaseous volume of determined composition and pressure.

[0021] Circuit 5 includes a supply line 15 comprising a first end connected to a portion of circuit 5 in which the working gas is not at its minimum pressure in circuit 5 (typically downstream of a compression stage) and a second end opening into the junction box 6.

[0022] The junction box 6 further includes at least one communication passage 9 with the interior of the engine casing 2. Where applicable, all or part of the electrical circuitry (cables, etc.) may pass through this passage 9 as shown schematically in the [ Fig.4 ].

[0023] Circuit 5 includes a return line 25 having a first end communicating with the interior of the housing 2 and a second end connected to circuit 5, in a portion of the circuit where the working gas is not at its maximum pressure, in particular at a pressure equal to or greater than the minimum pressure, for example upstream of the compression member 4. The supply line 15, the passage 9, and the return line 25 are thus configured to draw a fraction of the pressurized working gas flow in circuit 5 and circulate it through the junction box 6 to cool it before returning to circuit 5.

[0024] This allows the electrical supply enclosure (junction box 6) of an engine 3 or a turbomachine, for example, to be cooled using a flow of pressurized cycle gas circulating through the hermetic (or semi-hermetic) part of a junction box 6. This fluid flow can be achieved by supplying and extracting gas (or liquid) through pipes, machined cavities, and / or cable passages, for example.

[0025] In particular, as illustrated in the [ Fig.4 ], passage 9 may include a communication opening between the inside of the junction box 6 and the inside of the housing 2 and through which the cable assembly(ies) passes.

[0026] Preferably, passage 9 and the first end of the return line 25 which opens into the junction box 6 are located at opposite ends of the junction box 6 to promote efficient mixing and cooling by the cycle fluid flow.

[0027] The driving of this cooling fluid flow can be achieved by a dynamic pressure drop between the injection and discharge point of the engine or the pipes connecting to it.

[0028] As illustrated, preferably, the circuit 5 may include a flow control device 11 for the fluid circulating in the bypass line 15, for example a valve, a calibrated orifice, or any other suitable device (e.g., a pilot-operated valve). The flow control device 11 may be located on the supply line 15.

[0029] As illustrated, the circuit 5 may advantageously include a fluid flow cooling device 12, such as a heat exchanger, preferably located between the circulation device 4 (compression stage) and the first end of the supply line 15. This cooling device 12 may be a cooling heat exchanger conventionally located at the outlet of a compression stage to cool the compressed cycle gas flow (by exchanging heat with a heat transfer fluid, such as water or another fluid, for example).

[0030] The fluid circulation device 1 illustrated as an example in the [ Fig.1 ] is a motor-turbo compressor comprising a compression wheel and a turbine 16 mounted on the shaft 20 of the motor 3. Of course, this is only a non-limiting example because the invention could be applied to a simple motor-compressor (motor driving one or more compression wheels) or any other arrangement (one or more compression wheels and one or more turbines).

[0031] There [ Fig.2 ] describes an example of implementation in a refrigerator or liquefier producing cooling power by subjecting a cycle gas to a thermodynamic cycle in a working circuit.

[0032] The working circuit 5 may include, arranged in series, at least one cycle gas compression stage 4, at least one cycle gas cooling device 12, 14 (e.g., heat exchanger(s)), at least one cycle gas expansion stage 16 (e.g., turbine(s) or valve(s)), and at least one cycle gas heating device 17, 14 (e.g., heat exchanger(s)). The compression device 4 (at least one stage) may include a circulation device 1 of the aforementioned type.

[0033] A cycle gas cooling heat exchanger 12 at the outlet of the compression stage can ensure the cooling of the cycle gas which will be used to cool the junction box 6.

[0034] The cooling and heating of the cycle gas can be ensured by at least one counter-current heat exchanger 14 receiving a flow of cycle gas at different temperatures within the cycle. At its coldest end in the cycle, the cycle gas can be heated by releasing its cooling capacity through heat exchange with a component to be cooled in a heat exchanger 17 (e.g., a flow 13 of the fluid to be cooled or liquefied).

[0035] The invention can be applied to a device (refrigerator or other) comprising several motors 3, each having an electrical junction box 6. All or some of the motors may include a respective cooling system of the type described above. Alternatively, or in combination, motors may share or pool all or part of the cooling system described above.

[0036] In the non-limiting example of the [ Fig.3 The refrigeration / liquefaction installation 10 comprises two motors 3 and the two corresponding junction boxes 6 are cooled by the same cycle gas flow. The device includes in this example an expansion stage (a turbine 16).

[0037] More specifically, each motor 3 is equipped with a respective electrical junction box 6 communicating with the corresponding housing 2 via a passage 9. The supply line 15 includes a first end connected to the circuit 5, for example at a portion downstream of the drive element 4 of a first motor 3 (for example at the outlet of the second cycle gas compression stage).

[0038] Device 1 includes a transfer line 35 having a first end connected to the casing 2 of the first motor 3 and a second end opening into the junction box 6 of the second motor 3 (of the first compression stage upstream in the cycle gas working circuit). As illustrated, the transfer line 35 preferably includes a cycle fluid flow cooling element 13 such as a heat exchanger cooled by a heat transfer fluid (water, air, or other) to cool the cycle gas before it cools the second junction box 6.

[0039] The return line 25 comprises a first end communicating with the interior of the crankcase 2 of the second engine 3 and a second end connected to a portion of the fluid circuit 5, for example upstream of the first compression stage. As shown schematically in dashed lines, the return line 25 may optionally include a cooling device 25 for the cycle gas flow (heat exchanger or other) before its reinjection upstream of a compression stage.

[0040] Thus, the supply line 15, the transfer line 35, the passages 9 and the return line 25 allow a fraction of the compressed cycle gas to be taken and circulated in series through the junction boxes 6 in order to cool them before returning to the circuit 5.

[0041] The example of the [ Fig.3 ] has two series compression stages of cycle gases, each with a cooling exchanger 12 at the outlet of each compression stage. Similarly, the illustrated device has a single expansion stage (a turbine 16).

[0042] Of course, the invention can be applied to any other type of installation architecture and in particular any type of cryogenic refrigerator or liquefier (typically bringing a working gas to a temperature below -150°C) with one or more compression and expansion stages with a different number of motors.

[0043] The variant of the [ Fig.8 ] differs from that of the [ Fig.3 ] only in that the first end of the supply line 15 is connected between the two compressors 4 in series, for example downstream of the cooling exchanger 12.

[0044] Furthermore, the invention can be applied to a device 1 in which the motor 3 (or at least one of the motors) is replaced by any other electrical machine, for example, an alternator. In this case, the drive element 4 may include a turbine. The turbine(s) 16 may be provided for recovering mechanical work intended to produce electrical power.

[0045] Similarly, the first end of the supply pipe can be connected downstream of another component of the circuit 5, in particular downstream of a component 4 different from that driven or coupled to the electrical machine 3 whose junction box 6 must be cooled.

[0046] Typically, the first end of the supply line(s) 15 is preferably connected to a point in the circuit where the cycle gas pressure is higher than the lowest cycle gas pressure in the circuit 5. This is because the cycle gas undergoes a thermodynamic transformation in the circuit 5 (specifically, a compression / expansion cycle) between at least two states at low (minimum) and high (maximum) pressures. The cycle gas drawn from the circuit 5 to cool at least one junction box 6 is preferably at a pressure higher than its minimum pressure in the circuit 5.

[0047] For example, this cycle gas is taken from circuit 5 downstream of at least one of the compressors 4 of circuit 5.

[0048] For example, this cycle gas is taken downstream of the compressor 4, which is rotationally coupled to the shaft of the motor 3, whose junction box 6 must be cooled. However, this first end of the supply line 15 can be connected to the outlet of another compressor 4 (or other component 4) coupled to another motor 3 or electrical machine of the device 1.

[0049] Similarly, the second end of the return line 25 is preferably connected to a portion of the circuit in which the cycle gas pressure is relatively low (below the maximum pressure), for example to the inlet of one of the compressors 4. For example, the return line 25 is connected to the inlet of the compressor 4 coupled (driven) by the motor 4 whose junction box 6 is cooled by the cycle gas.

[0050] In the variant illustrated in the [ Fig.5 ], the device includes two motors 3 each driving a compressor 4. One of the motors 3 is also coupled to a turbine 16 via the same shaft driving the compressor.

[0051] Typically, each motor 3 can include a stator 32 and a rotor 31 coupled to a rotating shaft carrying the wheels (compressor(s) 4 and turbine(s) 16).

[0052] In this example, two supply lines 15 have a first end (common in this example) connected downstream of the first of two compressors 4 in series, for example, downstream of a compressed cycle gas cooling heat exchanger 12. The second ends of the two supply lines 15 are connected in parallel to the two casings 2, respectively. The pressurized cycle gas then flows into the junction boxes 6 via passages 9 and exits the box 6 and the casing 2 via return lines 25. The two return lines 25 can be reconnected to the inlet of the same compressor 4, for example, to the first of the two compressors in series. Thus, the pressurized cycle gas used for cooling the junction box 6 can first pass through the corresponding casing 2 before passing through the junction box 6.

[0053] As illustrated, the device 1 may further include a line 21 diverting a portion of this pressurized cycle gas to a labyrinth system 18 at the bearings of the motor shaft 3. Typically, this labyrinth system 18 is designed to separate the gaseous atmosphere in the crankcase 2 from the outside. That is, a line 21 can be connected in parallel to the supply line 15 to a labyrinth (or any bearing system). This line 21 (like the supply line 15) preferably includes a valve system 22 allowing independent opening or closing as required.

[0054] There [ Fig.6 This illustrates that the second end of the supply line 15 can open into the housing 2 and the junction box 6. A majority of the flow (for example, approximately 90% of the flow) supplies the housing 2 for cooling; the remainder of the flow supplies the interior of the junction box 6. The cycle gas flow that cools the junction box 6 returns to the housing 2 via a portion of the return line 25, which can contain the electrical cables (forming passage 9). The cooling cycle gas flows are symbolized by curved arrows.

[0055] In the implementation of the [ Fig.7], the second end of the supply line 15 opens into the crankcase 2, the cycle gas flow then passes into the junction box 6 via at least one passage 9 and then returns to the volume 2 of the crankcase 2. Thus, the injected cycle gas first passes into the engine crankcase 2 and then reaches the junction box 6 by passing for example through the same place as the electrical cables.

[0056] Thus, the pressurized cycle gas can be taken from the first end of at least one supply line 15 to any suitable location in the circuit 5 to be brought into a junction box 6 directly or via a casing 2 or other.

[0057] The invention makes it possible to provide compact junction boxes while ensuring efficient cooling of the latter.

[0058] In applications using frequencies of 100 Hz or higher, electric currents flow preferentially along the surface of conductive materials. The device is particularly well-suited for cooling components with such skin effects by reducing surface temperature.

[0059] In the example shown, only one electrical connection 7 is shown, but the invention could be applied to junction boxes 6 comprising several connections or spark plugs depending on the number of phases of the electric motor and the number of connections or spark plugs required to supply the electric motor.

[0060] The cooling efficiency also allows for a reduction in the cross-section of cables and other electrical components in the junction box 6.

[0061] The invention thus allows for an improvement in the thermal behavior and pressure resistance of the electrical junction to a motor.

Claims

1. A fluid circulation device, particularly for a refrigerator or cryogenic liquefier, comprising a casing (2) sealed with respect to the outside of the device (1) and containing an electric machine (3) such as an electric motor or an alternator, the device (1) comprising a cycle gas circuit (5) subjecting the cycle gas to a thermodynamic change between a minimum pressure and a maximum pressure when the device is in operation, the device comprising at least one means (4) for driving the cycle gas in the circuit (3) such as a compressor wheel, said drive means (4) being rotationally coupled to the electric machine (3), the device (1) comprising an electrical junction box (6) sealed with respect to the outside of the device and in which passes an electrical circuitry (8) having a first end connected to the electric machine (3) and a second end connected to at least one electrical connector (7) opening to the outside of the junction box (6) and located outside the casing (2), the device (1) comprising a supply line (15) for pressurized cycle gas comprising a first end connected to a portion of the circuit (5) in which the cycle gas is at a pressure higher than the minimum pressure and a second end communicating with the interior of the junction box (6), the junction box (6) comprising a communication passage (9) with the interior of the casing (2), the fluid circuit (5) comprising a return line (25) for the cycle gas comprising a first end communicating with the interior of the casing (2) and a second end connected to the circuit (5), the supply line (15), the passage (9) and the return line (25) being configured to withdraw a fraction of the cycle gas flowing in the circuit (5) to circulate it in the junction box (6) in order to cool the latter before returning to the circuit (5).

2. The device according to claim 1, wherein the first end of the supply line (15) is connected to the circuit (5) downstream of an outlet of a drive means (4).

3. The device according to claim 1 or 2, wherein the second end of the supply line (15) opens into the casing (2) and / or into the junction box (6).

4. The device according to any one of claims 1 to 3, wherein the first end of the return line (25) opens into the casing (2) and / or into the junction box (6).

5. The device according to any one of claims 1 to 4, wherein the second end of the return line (25) is connected to the circuit (5) upstream of an inlet of a drive means (4).

6. The device according to any one of claims 1 to 5, comprising a member (11) for regulating the flow of the fluid circulating in the supply line (15).

7. The device according to claim 6, wherein the flow regulating member (11) comprises at least one of: a valve, a calibrated orifice.

8. The device according to any one of claims 1 to 7, wherein the fluid circuit (5) comprises a member (12) for cooling the fluid flow such as a heat exchanger disposed between an outlet of the circulation means (4) and the first end of the branch line (15).

9. The device according to any one of claims 1 to 8, wherein the passage (9) and a first end of the return line (25) are located at opposite ends of the junction box (6).

10. The device according to any one of claims 1 to 9, wherein the electrical circuitry (8) which passes through the junction box (6) comprises a set of electrical cable(s) and wherein the passage (9) comprises a communication orifice between the interior of the junction box (6) and the interior of the casing (2) and through which the set of cable(s) extends.

11. The device according to any one of claims 1 to 10, comprising at least two distinct casings (2) each containing an electric machine (3) for driving respective drive means (4), each electric machine (3) being provided with a respective electrical junction box (6) communicating with the casing (2) via a passage (9), the device comprising at least two supply lines (15) for pressurized cycle gas, each comprising a first end connected to a portion of the circuit (5) in which the cycle gas is at a pressure higher than the minimum pressure and a second end communicating with the interior of a corresponding junction box (6).

12. The device according to claim 11, wherein the first end of a first supply line (15) to the casing of a first electric machine (3) is connected to the fluid circuit (5) downstream of the outlet of a first drive means (4), the device comprising a transfer line (35) having a first end connected to the casing (2) of the first electric machine (3) and a second end opening into the junction box (6) of the second electric machine (3), the device (1) comprising a return line (25) comprising a first end communicating with the second casing (2) and a second end connected to the circuit (5), the first supply line (15), the transfer line (35), the passages (9) and the return line (25) being configured to withdraw a fraction of the fluid flow flowing in the fluid circuit (5) to circulate it in series in the junction boxes (6) in order to cool them before returning to the circuit (5).

13. The device according to claim 11, comprising two supply lines (15) having first ends connected to the circuit (3) and second ends communicating in parallel respectively with the two junction boxes (6) and / or with the two casings (2).

14. The device according to claim 13, wherein the first ends of the two supply lines (15) are connected to a same portion of the circuit (3).

15. An installation (10) for refrigeration and / or liquefaction comprising a refrigerator having a working circuit (5) of a cycle gas, said circuit comprising, arranged in series, at least one compression stage (4) of the cycle gas, at least one cooling member (12, 14) for the cycle gas, at least one expansion stage (16) of the cycle gas and at least one reheating member (17, 14) for the cycle gas, comprising a circulation device (1) according to any one of claims 1 to 14, wherein the drive means (4) comprises a compressor wheel forming a compression stage.

16. The installation according to claim 15, wherein the at least one reheating member for the cycle gas comprises a heat exchanger (17) in thermal exchange with an element (19) to be cooled, for example a fluid flow.

17. The installation according to claim 15 or 16, wherein the cycle gas comprises at least one of: nitrogen, helium, hydrogen, argon, neon.

18. A method for cooling an electrical junction box (6) of an electric motor (2) of a circulation device according to any one of claims 1 to 14 or an installation according to any one of claims 15 to 17, comprising a step of withdrawing a fraction of the fluid flow flowing in the fluid circuit (5) and of circulating this fraction of fluid in the junction box (6) in order to cool the latter, then a step of returning this fraction of fluid to the fluid circuit (5).