WO2023025902A1

WO2023025902A1 - Thermal conditioning system for a motor vehicle

Info

Publication number: WO2023025902A1
Application number: PCT/EP2022/073708
Authority: WO
Inventors: Mohamed Yahia; Stefan Karl; Bertrand Nicolas
Original assignee: Valeo Systemes Thermiques
Priority date: 2021-08-26
Filing date: 2022-08-25
Publication date: 2023-03-02
Also published as: FR3126346A1

Abstract

The invention relates to a thermal conditioning system (100) comprising: - a main coolant fluid loop (A) successively comprising: -- a compressor (2) comprising an outlet (4) and at least one inlet (3a); -- a first exchanger (21) configured to exchange heat with a first heat-transfer fluid (F1); -- a first expansion device (5); -- a second exchanger (22) configured to exchange heat with an element (30) of a motor vehicle powertrain; - a first bypass branch (B) comprising a third exchanger (23) configured to exchange heat with a second heat-transfer fluid (F2); - a second bypass branch (C) comprising a second expansion device (7); - an internal heat exchanger (8) arranged both on the main loop (A) downstream of the first heat exchanger (21) and on the second bypass branch (C) downstream of the second expansion device (7).

Description

HEAT CONDITIONING SYSTEM FOR MOTOR VEHICLE

Technical area

[1] The present invention relates to the field of thermal conditioning systems. Such systems can in particular be fitted to motor vehicles. These systems allow, for example, thermal regulation of various parts of the vehicle, such as the passenger compartment or an electrical energy storage battery, in the case where the vehicle is electrically powered. Heat exchanges are mainly managed by the compression and expansion of a refrigerant fluid circulating in a closed circuit in which several heat exchangers are arranged.

Prior technique

[2] It is well known to heat the passenger compartment of the vehicle by condensing a high-pressure refrigerant fluid in a heat exchanger through which flows an air supplying the passenger compartment. The refrigerant is then evaporated in an exchanger carrying out a heat exchange with an air flow outside the vehicle. A thermodynamic cycle is thus carried out, and the heat extracted from the flow of outside air contributes to the heating of the passenger compartment. The heat exchanger carrying out the heat exchange with the outside air is generally placed in the front face of the vehicle.

[3] It is also known, in the case of an electric propulsion vehicle, to recover at least part of the heat dissipated by a member of the electric powertrain, also called an electric traction chain. This member may for example be an electrical energy storage battery. To achieve this recovery of thermal energy, the coolant is evaporated in a heat exchanger thermally coupled with the component of the electric motor. The heat dissipated by this component, as well as the heat extracted from the flow of outside air, then both contribute to heating the passenger compartment, which improves the heating power obtained as well as its energy efficiency. [4] In certain applications, it is advantageous not to use a heat exchanger placed on the front face of the vehicle. In this case, the heating of the passenger compartment is ensured thanks to the energy recovered from the powertrain, as well as by the energy supplied to the refrigerant fluid during its passage at high pressure.

[5] Such a configuration simplifies the mechanical integration of the system but has several drawbacks. In order to provide enough heat output, the refrigerant flow rate must be high enough. Such a flow tends to generate high pressure drops, which degrades the thermodynamic performance. Moreover, in such a thermodynamic cycle, the evaporation of the refrigerant fluid thanks to the heat recovered from the powertrain is generally inefficient, because the evaporator receives refrigerant fluid comprising a high gaseous fraction, which means that the transfer heat is inefficient.

[6] An object of the invention is to provide a thermal conditioning system allowing energy recovery from an electric powertrain which has improved efficiency. The invention also relates to a method of operating such a thermal conditioning system.

Summary

[7] To this end, the present invention proposes a thermal conditioning system comprising a refrigerant circuit configured to circulate a refrigerant fluid, the refrigerant circuit comprising:

A main loop comprising successively, depending on the direction of circulation of the refrigerant fluid:

- A compression device comprising an outlet and at least a first coolant inlet,

- A first heat exchanger configured to exchange heat with a first heat transfer fluid,

- A first relaxation device,

- A second heat exchanger configured to exchange heat with an element of a traction chain of a motor vehicle,

A first branch branch connecting a first point of connection arranged on the main loop downstream of the outlet of the compression device and upstream of the first heat exchanger to a second connection point arranged on the main loop downstream of the first heat exchanger and upstream of the first expansion device, the first bypass branch comprising a third heat exchanger configured to exchange heat with a second heat transfer fluid,

A second bypass branch connecting a third connection point arranged on the main loop downstream of the first heat exchanger and upstream of the first expansion device to a fourth connection point arranged on the main loop downstream of the second heat exchanger and upstream of the outlet of the compression device, the second bypass branch comprising a second expansion device,

- an internal heat exchanger arranged jointly on the main loop downstream of the second connection point as well as the third connection point, and upstream of the first expansion device and on the second bypass branch downstream of the second expansion device.

[8] This circuit architecture makes it possible in particular to divide the flow of refrigerant fluid between a part circulating in the second bypass branch C and a part circulating in the main loop A. This division of the flow of refrigerant fluid takes place at the level of the third connection point. The refrigerant circulating in the second bypass branch circulates at low pressure in the second heat exchange section of the internal exchanger. The refrigerant circulating in the main loop circulates at high pressure in the first heat exchange section of the internal exchanger. The high-pressure refrigerant fluid thus transfers heat to the low-pressure refrigerant fluid. The enthalpy of the high-pressure refrigerant has therefore decreased at the outlet of the internal exchanger. This makes it possible in particular to improve the heat transfer within the second heat exchanger, when the latter operates as an evaporator. When the second heat exchanger is thermally coupled to a heat source from which it is desired to recover part of the dissipated energy, the efficiency of the heat transfer in this second exchanger is improved, which makes it possible to improve the efficiency of the energy recovery. [9] The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

[10] The element of the traction chain of the motor vehicle is an electrical energy storage battery.

[11] The element of the traction chain of the motor vehicle is an electronic module for controlling an electric motor, for example an electric traction motor of the vehicle.

[12] According to one embodiment of the thermal conditioning system, the latter comprises a third bypass branch connecting a fifth connection point arranged on the main loop downstream of the internal heat exchanger and upstream of the first expansion at a sixth connection point disposed on the main loop downstream of the second heat exchanger and upstream of the first inlet of the compression device, the third bypass branch successively comprising a third expansion device and a fourth heat exchanger configured to exchange heat with a flow of air inside the passenger compartment of the motor vehicle.

[13] According to one embodiment, the first heat transfer fluid is a flow of air inside the passenger compartment of the motor vehicle.

[14] According to a variant, the first heat transfer fluid is a heat transfer liquid configured to exchange heat with a fifth heat exchanger, the fifth heat exchanger being configured to exchange heat with an interior air flow at the passenger compartment of the motor vehicle.

[15] According to one embodiment, the second heat transfer fluid is a flow of air outside the passenger compartment of the motor vehicle.

[16] Alternatively, the second heat transfer fluid is a heat transfer liquid configured to exchange heat with a sixth heat exchanger, the sixth heat exchanger being configured to exchange heat with an air flow outside the passenger compartment of the motor vehicle. [17] According to one embodiment of the thermal conditioning system, the fourth connection point is arranged upstream of the first coolant inlet of the compression device.

[18] According to another embodiment, the compression device comprises a second inlet for refrigerant fluid, and in which the fourth connection point is connected to the second inlet of the compression device.

[19] According to one embodiment of the thermal conditioning system, the latter comprises a fourth bypass branch connecting a seventh connection point arranged on the main loop downstream of the internal exchanger and upstream of the first expansion device to an eighth connection point disposed on the first branch branch between the third heat exchanger and the second connection point, the fourth branch branch comprising a fourth expansion device.

[20] The thermal conditioning system may further comprise a fifth branch branch connecting a ninth connection point arranged on the first branch branch between the first connection point and the third heat exchanger to a tenth connection point arranged on the main loop upstream of the first inlet of the compression device. The tenth connection point can be arranged on the main loop downstream of the fourth connection point and upstream of the first inlet of the compression device.

[21] The fifth branch branch includes a third shut-off valve.

[22] The fourth bypass branch and the fifth bypass branch may be present when the thermal conditioning system does not include a third bypass branch.

[23] When the third bypass branch is present, the seventh connection point is located on the main loop downstream of the internal exchanger and upstream of the fifth connection point.

[24] According to an alternative embodiment, the first heat exchanger comprises two heat exchange sections configured to be traversed in parallel by the refrigerant fluid. [25] According to one aspect of the thermal conditioning system, the main loop comprises a coolant accumulation device disposed downstream of the sixth connection point and upstream of the first inlet of the compression device.

[26] Alternatively or additionally, the main loop includes a coolant accumulation device disposed downstream of the first heat exchanger and upstream of the second connection point.

[27] The main loop has a first shut-off valve. The first shut-off valve is arranged between the first connection point and the first heat exchanger.

[28] The first branch branch has a second shut-off valve. The second shut-off valve is arranged between the first connection point and the third heat exchanger.

[29] The main loop includes a first non-return valve configured to block a flow of refrigerant fluid from the second connection point to the first heat exchanger.

[30] As a variant, the main loop comprises a shut-off valve configured to block a circulation of refrigerant fluid from the second connection point to the first heat exchanger.

[31] The first bypass branch includes a third non-return valve configured to block a flow of refrigerant fluid from the second connection point to the third heat exchanger. The third check valve is disposed between the third heat exchanger and the second connection point.

[32] As a variant, the first bypass branch comprises a shut-off valve configured to block a circulation of refrigerant fluid from the second connection point to the third heat exchanger.

[33] The third bypass branch comprises a second non-return valve configured to block a flow of refrigerant fluid from the sixth connection point to the fourth heat exchanger. The second check valve return is arranged between the fourth heat exchanger and the sixth connection point.

[34] As a variant, the third bypass branch comprises a shut-off valve configured to block a circulation of refrigerant fluid from the sixth connection point to the fourth heat exchanger.

[35] The fourth bypass branch comprises a fourth non-return valve configured to block a flow of refrigerant fluid from the eighth connection point to the seventh connection point.

[36] As a variant, the fourth bypass branch comprises a shut-off valve configured to block a circulation of refrigerant fluid from the eighth connection point to the seventh connection point.

[37] The invention also relates to a method of operating a thermal conditioning system as described above, in a so-called energy recovery mode, in which the refrigerant fluid circulates in the compression device where it passes to high pressure, and circulates successively in the first heat exchanger where it yields heat to the first heat transfer fluid, is divided between a first flow circulating in the second bypass branch and a second flow circulating in the main loop, the first flow circulates successively in the second expansion device where it passes at low pressure, in the internal heat exchanger where it receives heat from the second flow, and joins an inlet of the compression device, the second flow circulates successively in the heat exchanger internal where it yields heat to the first flow, in the first expansion device where it passes at low pressure, in the second sample heat sink where it absorbs heat, and joins the first inlet of the compression device.

[38] According to one embodiment, the first flow of coolant joins the main loop upstream of the first inlet of the compression device.

[39] According to another embodiment, the first coolant flow joins the second inlet of the compression device.

[40] According to one aspect of the operating method, a flow rate of the refrigerant at the outlet of the second expansion device is adjusted so that a superheat of the first flow of refrigerant at the outlet of the internal heat exchanger is between 5°C and 10°C.

[41] According to a variant implementation of the method, a flow rate of refrigerant fluid at the outlet of the second expansion device is adjusted so that overheating of the flow of refrigerant fluid circulating in the main loop downstream of the fourth point temperature is between 3°C and 10°C.

[42] The invention also relates to a method of operating a thermal conditioning system as described above, in a so-called heat pump and energy recovery mode, in which the refrigerant fluid circulates in the compression device where it passes at high pressure, and circulates successively in the first heat exchanger where it yields heat to the first heat transfer fluid, is divided between a first flow circulating in the second bypass branch and a second flow circulating in the main loop, the first flow successively circulates in the second expansion device where it passes at low pressure, in the internal heat exchanger where it receives heat from the second flow, joins the main loop and joins an inlet of the compression device, the second flow circulates successively in the internal heat exchanger where it yields heat to the first flow, is divided between a third flow circulating in the main loop and a fourth flow circulating in the fourth bypass branch, the third flow circulates in the first expansion device where it passes at low pressure, in the second heat exchanger where it absorbs heat, the fourth flow circulates in the fourth expansion device where it passes at low pressure, into the third heat exchanger where it absorbs heat from the second heat transfer fluid, and joins the main loop upstream of the first inlet of the compression device.

[43] This mode of operation improves the efficiency of the passenger compartment heating for the configurations of the thermal conditioning system in which the third heat exchanger is present.

[44] The invention also relates to a method of operating a thermal conditioning system as described above, in a mode said air conditioning, in which the refrigerant circulates in the compression device where it passes at high pressure, and circulates successively in the third heat exchanger where it yields heat to the second heat transfer fluid, is divided between a first flow circulating in the second bypass branch and a second flow circulating in the main loop, the first flow successively circulates in the second expansion device where it passes at low pressure, in the internal heat exchanger where it receives heat from the second flow, joins the main loop and joins an inlet of the compression device, the second flow circulates successively in the internal heat exchanger where it yields heat to the first flow, in the third expansion device where it passes at low pressure, in the fourth heat exchanger where it absorbs heat from the indoor airflow, and joins the main loop upstream of the first entry of the compression device.

[45] The internal heat exchanger here makes it possible to improve the cooling efficiency of the interior air flow in the fourth exchanger.

Brief description of the drawings

[46] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the appended drawings, in which:

[47] [Fig. 1] is a schematic view of a thermal conditioning system according to a first embodiment of the invention,

[48] [Fig. 2] is a schematic view of a thermal conditioning system according to a second embodiment of the invention,

[49] [Fig. 3] is a schematic view of a thermal conditioning system according to a third embodiment of the invention,

[50] [Fig. 4] is a schematic view of a thermal conditioning system according to a first variant of the third embodiment of the invention,

[51] [Fig. 5] is a schematic view of a thermal conditioning system according to a second variant of the third embodiment of the invention, [52] [Fig. 6] is a schematic view of a thermal conditioning system according to a third variant of the third embodiment of the invention,

[53] [Fig. 7] is a schematic view of the thermal conditioning system according to the third embodiment, operating according to a first mode of operation, called so-called energy recovery mode,

[54] [Fig. 8] is a schematic view of the thermal conditioning system according to the third embodiment, operating according to a second mode of operation, called heat pump and energy recovery,

[55] [Fig. 9] is a schematic view of the thermal conditioning system according to the third embodiment, operating according to a third operating mode, called said air conditioning mode,

[56] [Fig. 10] is a thermodynamic diagram illustrating the operation of the thermal conditioning system according to the first mode of operation, called so-called energy recovery mode.

Description of embodiments

[57] To make the figures easier to read, the various elements are not necessarily shown to scale. In these figures, identical elements bear the same references. Certain elements or parameters can be indexed, that is to say designated for example by first element or second element, or else first parameter and second parameter, etc. The purpose of this indexing is to differentiate between similar but not identical elements or parameters. This indexing does not imply a priority of one element or parameter over another and the denominations can be interchanged.

[58] In the following description, the term "a first element upstream of a second element" means that the first element is placed before the second element with respect to the direction of circulation, or course, of a fluid. Similarly, the term “a first element downstream of a second element” means that the first element is placed after the second element with respect to the direction of circulation, or travel, of the fluid in question. In the case of the refrigerant circuit, the term "a first element is upstream of a second element" means that the refrigerant successively passes through the first element, then the second element, bypassing the compression device. In other words, the refrigerant leaves the compression device, possibly passes through one or more elements, then passes through the first element, then the second element, then returns to the compression device, possibly after having passed through other elements.

[59] The term “a second element is placed between a first element and a third element” means that the shortest route to go from the first element to the third element passes through the second element.

[60] When it is specified that a subsystem comprises a given element, this does not exclude the presence of other elements in this subsystem.

[61] An electronic control unit, not shown in the figures, receives information from various sensors measuring in particular the characteristics of the refrigerant at various points in the circuit. The electronic control unit also receives instructions from the occupants of the vehicle, such as the desired temperature inside the passenger compartment. The electronic control unit implements control laws allowing the control of the various actuators, in order to ensure the control of the thermal conditioning system 100 so as to ensure the instructions received.

[62] Each of the expansion devices used can be an electronic expansion valve, a thermostatic expansion valve, or a calibrated orifice. In the case of an electronic expansion valve, the passage section allowing the refrigerant fluid to pass can be adjusted continuously between a closed position and a maximum open position. For this, the system control unit controls an electric motor which moves a mobile shutter controlling the section of passage offered to the refrigerant fluid.

[63] The compression device 2 can be an electric compressor, that is to say a compressor whose moving parts are driven by an electric motor. The compression device 2 comprises a suction side of the low pressure refrigerant fluid, also called inlet 3a of the compression device 2, and a discharge side of the high pressure refrigerant fluid, also called outlet 4 of the compression device 2. The moving parts compressor 2 internals pass the refrigerant from a low pressure on the inlet side 3a to a high pressure on the outlet side 4. After expansion in one or more expansion devices, the refrigerant fluid returns to the inlet 3a of the compressor 2 and begins a new thermodynamic cycle. According to another embodiment, the compression device 3 comprises two distinct inlets 3a, 3b and a single outlet 4. The second inlet 3b is at an intermediate pressure between the low pressure prevailing at the level of the first inlet 3a and the high pressure prevailing at the output 4. The compressor 2 can for example be a screw compressor. The first inlet 3a is located at one axial end of the screw, the outlet 4 is located at the opposite axial end, and the second inlet 3b is located axially between the first inlet 3a and the outlet 4.

[64] Each connection point allows the refrigerant to pass through one or other of the circuit portions joining at this connection point. The distribution of the refrigerant fluid between the portions of the circuit joining at a connection point is done by playing on the opening or closing of the shut-off valve, non-return valve or expansion device included on each of the branches. In other words, each connection point is a means of redirecting the refrigerant fluid arriving at this connection point.

[65] Shut-off valves and non-return valves thus make it possible to selectively direct the refrigerant fluid into the different branches of the refrigerant circuit, in order to ensure different modes of operation, as will be described later.

[66] The refrigerant used by the refrigerant circuit 1 is here a fluid such as R1234yf. Other refrigerants can also be used, such as R134a or R744, for example.

[67] Interior airflow Fi means an airflow intended for the passenger compartment of the motor vehicle. This interior air flow can circulate in a heating, ventilation and/or air conditioning installation, frequently designated by the English term “HVAC”, for “Heating, Ventilating and Air Conditioning”. This installation has not been shown in the various figures. A first motor-fan unit, not shown, is placed in the heating installation, ventilation and/or air conditioning in order to increase, if necessary, the flow rate of the interior air flow Fi.

[68] By exterior air flow Fe is meant an air flow that is not intended for the passenger compartment of the vehicle. In other words, this air flow Fe remains outside the passenger compartment of the vehicle. A second motor-fan unit, also not shown, can be activated in order to increase the flow rate of the outside air flow Fe if necessary. The air flow provided by the first as well as by the second motor-fan unit can be adjusted for example by the electronic control unit of the thermal conditioning system 100.

[69] There is shown in Figure 1 a thermal conditioning system 100 according to a first embodiment.

[70] To this end, the thermal conditioning system 100 comprises a circuit 1 of refrigerant fluid configured to circulate a refrigerant fluid, the circuit 1 of refrigerant fluid comprising:

A main loop A comprising successively, depending on the direction of circulation of the refrigerant fluid:

-- A compression device 2 comprising an outlet 4 and at least a first inlet 3a of refrigerant fluid,

- A first heat exchanger 21 configured to exchange heat with a first heat transfer fluid F1,

-- A first expansion device 5,

-- A second heat exchanger 22 configured to exchange heat with an element 30 of a traction chain of a motor vehicle,

A first bypass branch B connecting a first connection point 11 disposed on the main loop A downstream of the outlet 4 of the compression device 2 and upstream of the first heat exchanger 21 to a second connection point 12 disposed on the main loop A downstream of the first heat exchanger 21 and upstream of the first expansion device 5, the first bypass branch B comprising a third heat exchanger 23 configured to exchange heat with a second heat transfer fluid F2,

A second bypass branch C connecting a third connection point 13 arranged on the main loop A downstream of the first exchanger heat exchanger 21 and upstream of the first expansion device 5 to a fourth connection point 14, 14' arranged on the main loop A downstream of the second heat exchanger 22 and upstream of the outlet 4 of the compression device 2, the second branch C comprising a second expansion device

7,

- an internal heat exchanger 8 arranged jointly on the main loop A downstream of the second connection point 12 as well as the third connection point 13, and upstream of the first expansion device 5 and on the second bypass branch C downstream of the second expansion device 7.

[71] This circuit architecture makes it possible in particular to divide the flow of refrigerant fluid between a part circulating in the second bypass branch C and a part circulating in the main loop A. This division of the flow of refrigerant fluid takes place at the level of the third connection point 13. The refrigerant fluid circulating in the second bypass branch C circulates at low pressure in the second heat exchange section 10 of the internal exchanger

8. The refrigerant fluid circulating in the main loop A circulates at high pressure in the first heat exchange section 9 of the internal exchanger 8. The high pressure refrigerant fluid thus gives up heat to the low pressure refrigerant fluid. The enthalpy of the high-pressure refrigerant fluid has therefore decreased at the outlet of the internal exchanger 8. This makes it possible in particular to improve the heat transfer within the second heat exchanger 22, when the latter operates as an evaporator. When the second heat exchanger 22 is thermally coupled to a heat source from which it is desired to recover part of the dissipated energy, the efficiency of the heat transfer in the second exchanger 22 is improved, which makes it possible to improve the efficiency energy recovery.

[72] The internal heat exchanger 8 comprises a first heat exchange section 9 arranged on a portion of the main loop A arranged downstream of the second connection point 12 as well as downstream of the third connection point 13, and also arranged upstream of the first expansion device 5. The internal heat exchanger 8 comprises a second heat exchange section 10 arranged the second bypass branch C downstream of the second expansion device 7 and upstream of the fourth connection point 14. The internal heat exchanger 8 is configured to allow heat exchange between the refrigerant fluid in the first heat exchange section 9 and the refrigerant fluid in the second heat exchange section 10. The internal heat exchanger 8 is thus configured to allow heat exchange between the low-pressure refrigerant fluid at the outlet of the second expansion device 7 and the high-pressure refrigerant fluid circulating in the main loop downstream of the second connection point 12 as well as the third connection point 13. The second heat exchange section 10 is arranged on the second bypass branch C downstream of the second expansion device 7 and upstream of the fourth connection point 14. The second expansion device 7 can for example be a thermostatic expansion valve . In other words, this expansion device may be devoid of an electrical control member.

[73] In the example of Figure 1, the third connection point 13 coincides with the second connection point 12. In the example of Figure 2, the third connection point 13 can be arranged on the main loop A downstream of the second connection point 12 and upstream of the internal exchanger 8. Upstream of the first heat exchange section 9. According to a variant not shown, the third connection point 13 can be arranged on the main loop A upstream of the second connection point 12 and downstream of the first heat exchanger 21 . It is thus understood that the third connection point 13 is downstream of the outlet 21b of the first heat exchanger 21 .

[74] This circuit architecture makes it possible in particular to divide the flow of refrigerant fluid between a part circulating in the second bypass branch C and a part circulating in the main loop A. This division of the flow of refrigerant fluid takes place at the level of the third connection point 13. The refrigerant fluid circulating in the second bypass branch C circulates at low pressure in the second heat exchange section 10 of the internal exchanger 8. The refrigerant fluid circulating in the main loop A circulates at high pressure in the first heat exchange section 9 of the internal exchanger 8. The high-pressure refrigerant fluid thus transfers heat to the low-pressure refrigerant fluid. The enthalpy of the high pressure refrigerant fluid has therefore decreased at the outlet of the internal exchanger 8. This makes it possible in particular to improve the heat transfer within the second heat exchanger 22, when the latter operates as an evaporator. When the second heat exchanger 22 is thermally coupled to a heat source from which it is desired to recover part of the dissipated energy, the efficiency of the heat transfer in the second exchanger 22 is improved, which makes it possible to improve the efficiency energy recovery.

[75] Element 30 of the motor vehicle traction chain is here an electrical energy storage battery. The element 30 of the traction chain of the motor vehicle can also be an electronic module for controlling an electric motor, for example an electric traction motor of the vehicle. In normal operation, the electrical power supplied by the element 30 of the transmission chain dissipates heat in the refrigerant fluid when the latter passes through the second heat exchanger 22. The heat losses of the element 30 can thus be recovered, at least in part. The element 30 of the traction chain is thermally coupled to the second exchanger 22 by a heat transfer liquid circulating in a circuit 40. As before, the heat transfer liquid is a mixture of glycol water. A circulation pump, not shown, circulates the heat transfer liquid in the circuit 40. The energy dissipated by the element 30 is transferred to the heat transfer liquid. The heat transfer liquid of the circuit 40 exchanges heat with the refrigerant fluid of the second heat exchanger 22.

[76] According to one embodiment of the thermal conditioning system, the latter comprises a third bypass branch D connecting a fifth connection point 15 arranged on the main loop A downstream of the internal heat exchanger 8 and upstream from the first expansion device 5 to a sixth connection point 16 arranged on the main loop A downstream from the second heat exchanger 22 and upstream from the first inlet 3a of the compression device 2, the third bypass branch D successively comprising a third expansion device 6 and a fourth heat exchanger 24 configured to exchange heat with an air flow Fi inside the passenger compartment of the motor vehicle. [77] The fifth connection point 15 is arranged on the main loop A downstream of the first heat exchange section 9 of the internal exchanger 8.

[78] In the example illustrated in Figures 1 to 4, the first heat transfer fluid F1 is an air flow Fi inside the passenger compartment of the motor vehicle.

[79] According to a variant illustrated in Figure 5, the first heat transfer fluid F1 is a heat transfer liquid configured to exchange heat with a fifth heat exchanger 25, the fifth heat exchanger 25 being configured to exchange heat with a air flow Fi inside the passenger compartment of the motor vehicle. The heat transfer liquid circulates in a circuit 33 under the action of a pump 35. The heat transfer liquid is for example a mixture of water and glycol.

[80] In the example illustrated in Figures 1 to 4, the second heat transfer fluid F2 is a flow of air Fe outside the passenger compartment of the motor vehicle.

[81] According to a variant illustrated in Figure 6, the second heat transfer fluid F2 is a heat transfer liquid configured to exchange heat with a sixth heat exchanger 26, the sixth heat exchanger 26 being configured to exchange heat with a air flow Fe outside the passenger compartment of the motor vehicle. The heat transfer liquid F2 likewise circulates in a circuit 34. As before, the heat transfer liquid can be a mixture of water and glycol. A pump 36 ensures the circulation of the heat transfer liquid in the circuit 34. The circuit 34 is in the example illustrated independent of the circuit 33, that is to say that the two circuits cannot be placed in fluid communication. It is also possible for circuit 33 and circuit 34 to be interconnected. The choice of the second heat transfer fluid F2 is independent of the choice of the first heat transfer fluid F1. Circuit 33 is independent of circuit 40. Similarly, circuit 34 is independent of circuit 40.

[82] According to a first embodiment of the thermal conditioning system 100, illustrated in Figure 1, the fourth connection point 14 is arranged upstream of the first refrigerant inlet 3a of the compression device 2. The compression device 2 here comprises a single input 3a and a single output 4. [83] According to a second embodiment, illustrated in Figure 2, the compression device 2 has a second inlet 3b of refrigerant fluid, and the fourth connection point 14 is connected to the second inlet 3b of the compression device 2. The second coolant inlet 3b is separate from the first coolant fluid inlet 3a. The refrigerant is at low pressure at the first inlet 3a. The refrigerant fluid is at high pressure at outlet 4. At second inlet 3b, the refrigerant fluid is at an intermediate pressure between low pressure and high pressure. The compression device 2 here comprises two inputs 3a, 3b and a single output 4.

[84] The fourth connection point 14 can coincide with the second input 3b of the compression device 2. The fourth connection point 14 can also be connected to the second input 3b of the compression device 2 by a circuit portion having exactly one inlet and exactly one refrigerant outlet. In other words, the fourth connection point 14 can be connected to the second inlet 3b of the compression device 2 by a tubular portion, as is the case in the example illustrated.

[85] Figure 3 depicts a third embodiment. In this embodiment, the thermal conditioning system 100 comprises a fourth bypass branch E connecting a seventh connection point 17 disposed on the main loop A downstream of the internal exchanger 8 and upstream of the first expansion device 5 to an eighth connection point 18 disposed on the first branch B between the third heat exchanger 23 and the second connection point 12. The fourth branch E includes a fourth expansion device 28. In the example shown here, the thermal conditioning system 100 comprises a third bypass branch D defining a fifth connection point 15 and a sixth connection point 16. The seventh connection point 17 is thus arranged on the main loop A downstream of the internal exchanger 8 and upstream of the fifth connection point 15.

[86] The thermal conditioning system 100 also includes a fifth bypass branch F connecting a ninth connection point 19 arranged on the first bypass branch B between the first connection point 11 and the third heat exchanger 23 to a tenth connection point 20 arranged on the main loop A upstream of the first inlet 3a of the compression device 2. More specifically, the tenth connection point 20 is here arranged on the main loop A downstream from the fourth connection point 14 and upstream from the first inlet 3a of the compression device 2. The fourth bypass branch E and the fifth bypass branch F allow operation of the system according to a so-called heat pump mode.

[87] The tenth connection point 20 is arranged on the main loop A between the fourth connection point 14 and the first input 3a of the compression device 2. The tenth connection point 20 can be confused with the fourth connection point 14 .

[88] According to an alternative embodiment, illustrated in Figure 4, the first heat exchanger 21 comprises two heat exchange sections 31, 32 configured to be traversed in parallel by the refrigerant. The pressure drop generated by the first heat exchanger 21 can thus be minimized, since each heat exchange section 31, 32 is traversed by a fraction of the total flow. The two heat exchange sections 31, 32 are configured to exchange heat with the first heat transfer fluid F1. More specifically, in the example illustrated the two heat exchange sections 31, 32 are configured to exchange heat with the interior air flow Fi.

[89] The main refrigerant loop A comprises a refrigerant fluid accumulation device 29 disposed downstream of the sixth connection point 16 and upstream of the first inlet 3a of the compression device 2.

[90] The refrigerant fluid accumulation device 29 is arranged upstream of the fourth connection point 14. In other words, in a configuration with a compressor comprising a single inlet, the accumulation device 29 is arranged on the circuit portion between the sixth connection point 16 and the fourth connection point 14. When the fifth branch F is present, the storage device 29 is arranged upstream of the tenth connection point 20. [91] According to the embodiment illustrated in Figure 5, a coolant accumulation device 29 'is disposed downstream of the first heat exchanger 21, and upstream of the second connection point 12. The first heat transfer fluid F1 is in this case a heat transfer liquid. The refrigerant fluid accumulation device 29' is a dehydrating bottle. In the example of FIG. 5, the system 100 has two separate refrigerant fluid accumulation devices 29, 29'. It is also possible to have a single refrigerant fluid accumulation device, which is then the dehydrating bottle 29' placed downstream of the first heat exchanger 21 .

[92] Refrigerant circuit 1 includes several shut-off valves. Each shut-off valve makes it possible to selectively authorize or prohibit the circulation of refrigerant fluid through the valve. Various modes of operation can thus be ensured. Each stop valve is controlled for example by the electronic control unit of the thermal conditioning system 100. The main loop A comprises a first stop valve 41 . The first shut-off valve 41 is arranged between the first connection point 11 and the first heat exchanger 21. The first bypass branch B comprises a second shut-off valve 42. The second shut-off valve 42 is arranged between the first connection point 11 and the third heat exchanger 23. The fifth bypass branch F comprises a third valve stop 43. This stop valve 43 makes it possible to selectively interrupt the circulation of refrigerant fluid in the branch F.

[93] The refrigerant circuit 1 also includes several check valves. A non-return valve is a passive component, i.e. operating without electrical control. The main loop A comprises a first non-return valve 51 configured to block a circulation of refrigerant fluid from the second connection point 12 to the first heat exchanger 21. The first non-return valve 51 is placed between the first heat exchanger 21 and the second connection point 12. The first non-return valve 51 is configured to block a circulation of refrigerant fluid from the second connection point 12 to the outlet 21b of the first heat exchanger 21 .

[94] According to a variant not shown, the main loop A comprises a shut-off valve configured to block a circulation of refrigerant fluid from the second connection point 12 to the first heat exchanger 21. The shut-off valve is thus used instead of the non-return valve.

[95] The first bypass branch B has a third non-return valve

53 configured to block a circulation of refrigerant fluid from the second connection point 12 to the third heat exchanger 23. The third non-return valve 53 is arranged between the third heat exchanger 23 and the second connection point 12. The third non-return valve 53 is configured to block a flow of refrigerant fluid from the second connection point 12 to the first connection point 11.

[96] As before, according to a variant not shown, the first bypass branch B comprises a shut-off valve configured to block a circulation of refrigerant fluid from the second connection point 12 to the third heat exchanger 23.

[97] The third bypass branch D includes a second check valve 52 configured to block a flow of refrigerant fluid from the sixth connection point 16 to the fourth heat exchanger 24. The second check valve 52 is arranged between the fourth heat exchanger 24 and the sixth connection point 16. The second non-return valve 52 is configured to block a circulation of refrigerant fluid from the sixth connection point 16 to the outlet 24b of the fourth heat exchanger 24. Similarly , according to a variant not shown, the third bypass branch D comprises a shut-off valve configured to block a circulation of refrigerant fluid from the sixth connection point 16 to the fourth heat exchanger 24.

[98] The fourth bypass branch E includes a fourth non-return valve

54 configured to block a circulation of refrigerant fluid from the eighth connection point 18 to the seventh connection point 17. As before, the fourth bypass branch E may include a shut-off valve configured to block a circulation of refrigerant fluid from the eighth connection point 18 to the seventh connection point 17.

[99] Figures 7 to 9 schematically illustrate several modes of operation of a thermal conditioning system 100 as described previously, in particular in FIG. 3. In these figures, the portions of refrigerant circuit 1 in which refrigerant fluid circulates are shown in thick lines. The portions of circuit 1 in which the refrigerant fluid does not circulate are shown in dotted lines. The element 30 of the traction chain is here an electrical energy storage battery, which supplies the electric motor ensuring the traction of the vehicle. The battery 30 thus tends to dissipate heat when the vehicle is moving.

[100] Figure 7 schematically describes a method of operating a thermal conditioning system 100, in a so-called energy recovery mode. In this so-called energy recovery operating mode, the refrigerant circulates in the compression device 2 where it passes at high pressure, and successively circulates in the first heat exchanger 21 where it transfers heat to the first heat transfer fluid F1 , is divided between a first flow Q1 circulating in the second bypass branch C and a second flow Q2 circulating in the main loop A, the first flow Q1 circulates successively in the second expansion device

7 where it passes at low pressure, in the internal heat exchanger 8 where it receives heat from the second flow Q2, and joins an inlet 3a, 3b of the compression device 2, the second flow Q2 circulates successively in the exchanger internal heat

8 where it transfers heat to the first flow Q1, in the first expansion device 5 where it passes at low pressure, in the second heat exchanger 22 where it absorbs heat, and joins the first inlet 3a of the compression device 2.

[101] Figure 10 is a pressure diagram, enthalpy of the refrigerant during the thermodynamic cycle carried out in so-called energy recovery mode. The line designated by the sign S corresponds to the saturation curve of the refrigerant fluid used in circuit 1 . Point A3a illustrates the state of the low-pressure refrigerant fluid at the inlet 3a of compressor 2, and point A4 illustrates the state of the high-pressure refrigerant fluid at the outlet 4 of compressor 2. Point A3 illustrates the state of the flow Q of high-pressure refrigerant fluid at the outlet of the first exchanger 3. Point A4 illustrates the state of the low-pressure refrigerant fluid in outlet of the first expansion device 4. Point A13 illustrates the state of the flow of refrigerant Q at the level of the third connection point 13. At this point, the flow Q is divided between a flow Q1 and a flow Q2. Point A7 illustrates the state of the flow Q1 at the outlet of the second regulator 7, that is to say at low pressure. Point A14 illustrates the state of the flow Q1 at the level of the fourth connection point 14, in other words after heat exchange in the internal exchanger 8. At the level of point A14, the flow Q1 is overheated, that is to say at a temperature above the saturation temperature corresponding to the pressure of point A14. Point A15 illustrates the state of flow Q2 at the level of the fifth connection point 15, that is to say after heat exchange in the internal exchanger 8. Point A5 corresponds to the state of flow Q2 at the outlet of the first expansion valve 5. The point A16 corresponds to the state of the flow Q2 at the level of the sixth connection point 16. The refrigerant fluid is mainly in gaseous form, with a liquid fraction. The flow Q2 and the flow Q1 meet at the level of the fourth connection point 14 then the total flow Q of refrigerant fluid joins the inlet 3a of the compressor 2. The point A3a illustrates the state of the mixing point between the flow Q1 and the flow Q2. The second flow Q2 of refrigerant fluid, which is at high pressure when it passes through the internal heat exchanger 8, transfers heat to the first flow of refrigerant fluid Q1, which is at low pressure when it passes through the exchanger internal 8. The heat exchange in the internal exchanger 8 is quantified by the enthalpy difference between point A7 and point A14 on the one hand, and by the enthalpy difference between point A13 and point A15 on the other hand. The second flow Q2 is therefore cooled, which causes the liquid fraction of the second flow of refrigerant Q2 to increase. The heat exchange carried out in the second heat exchanger 22, after expansion in the first expansion device 5, is thus improved. Indeed, the second heat exchanger 22 then operates as an evaporator, and the heat transfer in this evaporator is improved when the liquid fraction of the refrigerant fluid increases. The quantity of energy recovered from the battery 30 at the level of the second heat exchanger 22 is thus increased. The thermal power that it is possible to dissipate in the interior air flow Fi in order to heat the passenger compartment is increased. The heating of the passenger compartment of the vehicle from the energy recovered from the traction chain is improved. In this operating mode, the refrigerant fluid does not circulate in the third heat exchanger. heat 23. This mode of operation is therefore particularly suited to the configurations of the thermal conditioning system 100 in which the third exchanger 23 is not present. The heating of the passenger compartment is carried out from the energy given to the refrigerant fluid by the compression device 2 and from the energy recovered from the traction chain.

[102] According to the example of Figure 7, the first flow of refrigerant Q1 joins the main loop A upstream of the first inlet 3a of the compression device 2.

[103] According to another embodiment, not shown, the compressor 2 may be a compressor comprising two separate inputs 3a, 3b, and an output. The first flow of refrigerant Q1 joins the second inlet 3b of the compression device 2. In other words, the first flow of refrigerant joins the inlet of the compressor 2 which is at an intermediate pressure between the low pressure prevailing at the level of the first inlet 3a and the high pressure prevailing at the outlet 4. The principle of operation according to this so-called energy recovery mode remains unchanged.

[104] To ensure this mode of operation, the first valve 41 is open and allows circulation of refrigerant fluid, the second shut-off valve 42 and the third shut-off valve 43 are both closed and block the passage of fluid refrigerant. The first expansion valve 5 as well as the second expansion valve 7 are at least partially open, so as to allow circulation of refrigerant fluid. The third expansion device 6 and the fourth expansion device 28 are both in the closed position so as to block the circulation of refrigerant fluid.

[105] According to one aspect of the method of operation, a flow rate of refrigerant at the outlet of the second expansion device 7 is adjusted so that overheating of the first flow Q1 of refrigerant at the outlet of the internal heat exchanger 8 is between 5°C and 10°C.

[106] Overheating means the difference between the actual temperature of the refrigerant, which is at a given pressure, and the condensation temperature of the refrigerant corresponding to this given pressure. zero overheating corresponds to saturated steam. When the superheat is positive, the refrigerant is entirely in vapor form.

[107] The first flow of refrigerant Q1, in the form of superheated vapor, joins the second flow of refrigerant Q2 which includes a fraction in liquid form. The liquid fraction of the mixture obtained is thus lower than that of the second flow rate Q2 of refrigerant fluid. The quantity of liquid refrigerant capable of reaching the first inlet of the compressor 3a is thus reduced. The amount of energy recovered at the level of the second heat exchanger 22 is thus optimized while optimizing the operation of the compression device 2.

[108] According to a variant implementation of the method, a flow rate of refrigerant fluid at the outlet of the second expansion device 7 is adjusted so that overheating of the flow rate of refrigerant fluid circulating in the main loop A downstream of the fourth connection point 14 is between 3°C and 10°C.

[109] The fourth connection point 14 is the point where the first flow Q1 and the second flow Q2 meet, before joining the inlet 3a of the compression device 2. The refrigerant flowing in the main loop portion A included between the fourth connection point 14 and the inlet 3a of the compression device 2 is in the gaseous state, since the refrigerant fluid is overheated. The pressure drop in this portion of the circuit is thus lower than when a fraction of the refrigerant fluid is in the liquid state. Thus, the control of the level of expansion ensured by the second expansion device 7 makes it possible to reduce the pressure drop in the refrigerant circuit 1 . The coefficient of performance of the thermal conditioning system 100 is thus improved.

[110] Figure 8 illustrates the operation of the thermal conditioning system 100 according to another mode of operation. According to this method of operation in a so-called heat pump and energy recovery mode, the refrigerant fluid circulates in the compression device 2 where it passes at high pressure, and successively circulates in the first heat exchanger 21 where it yields heat to the first heat transfer fluid F1, is divided between a first flow Q1 circulating in the second bypass branch C and a second flow Q2 circulating in the main loop A, the first flow Q1 circulates successively in the second expansion device 7 where it passes at low pressure, into the internal heat exchanger 8 where it receives heat from the second flow Q2, joins the main loop A and joins an inlet 3a, 3b of the compression device 2, the second flow Q2 circulates successively in the internal heat exchanger

8 where it yields heat to the first flow Q1, is divided between a third flow Q3 circulating in the main loop A and a fourth flow Q4 circulating in the fourth bypass branch E, the third flow Q3 circulates in the first expansion device 5 where it passes at low pressure, in the second heat exchanger 22 where it absorbs heat, the fourth flow Q4 circulates in the fourth expansion device 28 where it passes at low pressure, in the third heat exchanger 23 where it absorbs heat from the second heat transfer fluid F2, and joins the main loop A upstream of the first inlet 3a of the compression device 2.

[111] This mode of operation differs from the previous mode of operation in that part of the flow of refrigerant fluid, designated by Q4, circulates in the third heat exchanger 23. The flow Q4 is expanded at low pressure in the fourth expansion valve 28. The heat necessary for the evaporation of the refrigerant fluid in the third heat exchanger 23 is provided by the second heat transfer fluid F2. The second heat transfer fluid can be a heat transfer fluid circulating in a closed circuit, as is the case in the variant illustrated in FIG. 6. In the example illustrated in FIGS. 7 to 9, the second heat transfer fluid F2 is the flow of outdoor air Fe. In this mode of operation, the heat recovered from the coil 30 and the heat recovered from the outdoor air flow Fe both contribute to dissipating heat in the indoor air flow Fi at the level of the first exchanger heat 21 . The distribution of the flow Q2 between the flow Q3 and the flow Q4 is achieved by adjusting the passage section of the first regulator 5 and that of the fourth regulator 28.

[112] This mode of operation makes it possible to improve the efficiency of the heating of the passenger compartment for the configurations of the thermal conditioning system in which the third heat exchanger 23 is present. [113] Figure 9 illustrates the operation of the thermal conditioning system 100 according to a third mode of operation. According to this mode of operation of the thermal conditioning system 100, called air conditioning mode, the refrigerant circulates in the compression device 2 where it passes at high pressure, and circulates successively in the third heat exchanger 23 where it yields heat. to the second heat transfer fluid F2, is divided between a first flow Q1 circulating in the second bypass branch C and a second flow Q2 circulating in the main loop A, the first flow Q1 circulates successively in the second expansion device

7 where it passes at low pressure, into the internal heat exchanger 8 where it receives heat from the second flow Q2, joins the main loop A and joins an inlet 3a, 3b of the compression device 2, the second flow Q2 circulates successively in the internal heat exchanger

8 where it yields heat to the first flow Q1, in the third expansion device 6 where it passes at low pressure, in the fourth heat exchanger 24 where it absorbs heat from the internal air flow Fi, and joins the main loop A upstream of the first input 3a of the compression device 2.

[114] As before, the second heat transfer fluid F2 is the external air flow Fe. The second heat transfer fluid F2 can also be a heat transfer fluid circulating in a closed circuit. In this mode of operation, the third heat exchanger 23 operates as a condenser. The fourth heat exchanger 24 operates as an evaporator. The internal heat exchanger 8 here makes it possible to improve the efficiency of the cooling of the internal air flow Fi in the fourth exchanger 24.

Claims

28 Claims

[Claim 1] Thermal conditioning system (100) comprising a circuit (1) of refrigerant fluid configured to circulate a refrigerant fluid, the circuit (1) of refrigerant fluid comprising:

A main loop (A) successively comprising, depending on the direction of circulation of the refrigerant fluid:

-- A compression device (2) comprising an outlet (4) and at least a first inlet (3a) for refrigerant fluid,

-- A first heat exchanger (21) configured to exchange heat with a first heat transfer fluid (F1),

-- A first expansion device (5)

-- A second heat exchanger (22) configured to exchange heat with an element (30) of a traction chain of a motor vehicle,

A first bypass branch (B) connecting a first connection point (1 1) arranged on the main loop (A) downstream of the outlet (4) of the compression device (2) and upstream of the first heat exchanger ( 21) to a second connection point (12) disposed on the main loop (A) downstream of the first heat exchanger (21) and upstream of the first expansion device (5), the first bypass branch (B) comprising a third heat exchanger (23) configured to exchange heat with a second heat transfer fluid (F2),

A second bypass branch (C) connecting a third connection point (13) arranged on the main loop (A) downstream of the first heat exchanger (21) and upstream of the first expansion device (5) to a fourth point connection (14, 14') arranged on the main loop (A) downstream of the second heat exchanger (22) and upstream of the outlet (4) of the compression device (2), the second bypass branch (C ) comprising a second expansion device (7),

- an internal heat exchanger (8) arranged jointly on the main loop (A) downstream of the second connection point (12) as well as the third connection point (13), and upstream of the first expansion device (5) and on the second bypass branch (C) downstream of the second expansion device (7). [Claim 2] Thermal conditioning system according to claim 1, comprising a third bypass branch (D) connecting a fifth connection point (15) arranged on the main loop (A) downstream of the internal heat exchanger (8 ) and upstream of the first expansion device (5) at a sixth connection point (16) arranged on the main loop (A) downstream of the second heat exchanger (22) and upstream of the first inlet (3a) of the compression device

(2), the third bypass branch (D) successively comprising a third expansion device (6) and a fourth heat exchanger (24) configured to exchange heat with an air flow (Fi) inside the passenger compartment of the motor vehicle.

[Claim 3] Thermal conditioning system according to claim 1 or 2, in which the first heat transfer fluid (F1) is an air flow (Fi) inside the passenger compartment of the motor vehicle, and in which the second heat transfer fluid ( F2) is an air flow (Fe) outside the passenger compartment of the motor vehicle.

[Claim 4] Thermal conditioning system according to one of the preceding claims, in which the fourth connection point (14) is arranged upstream of the first refrigerant fluid inlet (3a) of the compression device (2).

[Claim 5] Thermal conditioning system according to one of Claims 1 to 3, in which the compression device (2) comprises a second inlet (3b) for refrigerant fluid, and in which the fourth connection point (14) is connected to the second input (3b) of the compression device (2).

[Claim 6] Thermal conditioning system according to one of the preceding claims, comprising a fourth bypass branch (E) connecting a seventh connection point (17) arranged on the main loop (A) downstream of the internal exchanger ( 8) and upstream of the first expansion device (5) at an eighth connection point (18) arranged on the first branch branch (B) between the third heat exchanger (23) and the second connection point (12) , the fourth bypass branch (E) comprising a fourth expansion device (28), the thermal conditioning system comprising a fifth branch branch (F) connecting a ninth connection point (19) disposed on the first branch branch (B) between the first connection point (1 1) and the third heat exchanger ( 23) to a tenth connection point (20) arranged on the main loop (A) upstream of the first inlet (3a) of the compression device (2).

[Claim 7] Method of operating a thermal conditioning system (100) according to one of Claims 1 to 6, in a so-called energy recovery mode, in which the refrigerant fluid circulates in the compression device (2 ) where it passes at high pressure, and circulates successively in the first heat exchanger (21) where it yields heat to the first heat transfer fluid (F1), is divided between a first flow (Q1) circulating in the second bypass branch (C) and a second flow (Q2) circulating in the main loop (A), the first flow (Q1) circulates successively in the second expansion device

(7) where it passes at low pressure, into the internal heat exchanger (8) where it receives heat from the second flow (Q2), and joins an inlet (3a, 3b) of the compression device (2), the second flow (Q2) circulates successively in the internal heat exchanger

(8) where it yields heat to the first flow (Q1), in the first expansion device (5) where it passes at low pressure, in the second heat exchanger (22) where it absorbs heat, and joins the first input (3a) of the compression device (2).

[Claim 8] Operating method according to claim 7, in which a flow rate of the refrigerant fluid at the outlet of the second expansion device (7) is adjusted so that superheating of the first flow rate (Q1) of refrigerant fluid at the outlet of the internal heat exchanger (8) is less than 10°C, preferably between 5°C and 10°C.

[Claim 9] Operating method according to claim 7, in which a flow rate of the refrigerant fluid at the outlet of the second expansion device (7) is adjusted so that superheating of the flow of refrigerant fluid circulating in the main loop (A) downstream of the fourth connection point (14) is less than 10°C, preferably between 3°C and 10°C.

[Claim 10] Method of operating a thermal conditioning system (100) according to claim 6, in a so-called heat pump and energy recovery mode, in which the refrigerant fluid circulates in the compression device (2) where it passes at high pressure, and circulates successively in the first heat exchanger (21) where it yields heat to the first heat transfer fluid (F1), is divided between a first flow (Q1) circulating in the second bypass branch (C ) and a second flow (Q2) circulating in the main loop (A), the first flow (Q1) circulates successively in the second expansion device

(7) where it passes at low pressure, into the internal heat exchanger (8) where it receives heat from the second flow (Q2), joins the main loop (A) and joins an inlet (3a, 3b) of the compression device (2), the second flow (Q2) circulates successively in the internal heat exchanger

(8) where it yields heat to the first flow (Q1), splits between a third flow (Q3) circulating in the main loop (A) and a fourth flow (Q4) circulating in the fourth bypass branch (E) , the third flow (Q3) circulates in the first expansion device (5) where it passes at low pressure, in the second heat exchanger (22) where it absorbs heat, the fourth flow (Q4) circulates in the fourth expansion device (28) where it passes at low pressure, into the third heat exchanger (23) where it absorbs heat from the second heat transfer fluid (F2), and joins the main loop (A) upstream of the first inlet (3a) of the compression device (2).