FR3164145A1 - Automotive Vehicle Thermal Conditioning System - Google Patents

Abstract

The invention relates to a thermal conditioning system (100) for a motor vehicle, comprising a refrigerant circuit (10) including: - a main loop (A) comprising successively: - a compressor (7), - a first heat exchanger (1) thermally coupled to an interior airflow (Fi) to a passenger compartment of a motor vehicle, - a first expansion valve (21), - a second heat exchanger (2) thermally coupled to an exterior airflow (Fe) to the passenger compartment of the motor vehicle, - a second expansion valve (22), - a third heat exchanger (3), - a first branch (B) of the main loop (A), - a second branch (C) of the main loop (A), comprising a third expansion valve (23) and a fourth heat exchanger (4) configured to exchange heat with the interior airflow (Fi), - a third branch (D) connecting the second branch (C) to The main loop (A). Abstract figure: Figure 3

Description

Automotive Vehicle Thermal Conditioning System

The present invention relates to the field of thermal conditioning systems. Such systems can, for example, be used in motor vehicles. These systems ensure thermal regulation of various vehicle components, such as the passenger compartment or an electrical energy storage battery, when the vehicle is electrically powered. Heat exchange is managed primarily by the compression and expansion of a refrigerant circulating in a circuit containing several heat exchangers. A compressor forces the refrigerant into a high-pressure state, allowing its circulation within the circuit.

It is well known that the passenger compartment of an electric vehicle is heated by operating the climate control system in a mode known as a heat pump. In this mode, the heat from the condensation of a refrigerant fluid, which is circulated under high pressure, heats the passenger compartment. The heat required for the evaporation of the refrigerant is supplied by the air outside the vehicle, i.e., the ambient air.

It is also well known to cool the vehicle's passenger compartment by operating the climate control system in a mode called air conditioning, in which the heat from the condensation of the refrigerant is dissipated into the outside air, and the refrigerant is evaporated in a heat exchanger located inside the passenger compartment. Other operating modes are also possible, for example, to dehumidify the air inside the passenger compartment, or to recover some of the heat dissipated by the electric vehicle's operation, for example, by its batteries.

The refrigerant circuit includes a series of branch lines and shut-off valves that allow the refrigerant to be selectively routed through different sections of the circuit to achieve various operating modes. To improve the vehicle's energy efficiency, a wide range of operating modes is desirable, which can result in a more complex refrigerant circuit.

It is therefore desirable to have thermal conditioning systems with improved energy efficiency without increasing the complexity of the circuit.

Summary

To this end, a thermal conditioning system for motor vehicles is proposed, comprising a refrigerant circuit configured to circulate a refrigerant, the refrigerant circuit comprising:
- a main loop comprising successively, according to the direction of refrigerant flow:
-- a compressor,
-- a first heat exchanger thermally coupled to an airflow inside the passenger compartment of a motor vehicle,
-- a first regulator,
-- a second heat exchanger thermally coupled to an outside airflow into the passenger compartment of the motor vehicle,
-- a second regulator,
-- a third heat exchanger,
- a first branch connecting a first connection point located on the main loop downstream of the first expansion valve and upstream of the second heat exchanger to a second connection point located on the main loop downstream of the second heat exchanger and upstream of the third heat exchanger,
- a second branch connecting a third connection point located on the main loop downstream of the first exchanger and upstream of the second exchanger to a fourth connection point located on the main loop downstream of the third exchanger and upstream of the compressor, the second branch successively comprising a third expansion valve and a fourth heat exchanger configured to exchange heat with the indoor airflow,
- a third branch connecting a fifth connection point located on the second branch between the third connection point and the third regulator to a sixth connection point located on the main loop downstream of the second exchanger and upstream of the second regulator.

This refrigerant circuit architecture allows for numerous different operating modes. Furthermore, this architecture allows the refrigerant to flow through the second heat exchanger in opposite directions depending on whether it is operating as an evaporator or a condenser. This makes it possible to optimize the design of the second heat exchanger to achieve better heat exchange performance than when the flow direction remains the same for both condensation and evaporation modes.

The features listed in the following paragraphs can be implemented independently of each other or in any technically possible combination:

According to one aspect of the thermal conditioning system, the main loop includes a refrigerant fluid accumulation device located downstream of the third exchanger and upstream of a compressor inlet.

The refrigerant fluid accumulation device is located between the fourth connection point and the compressor inlet.

The portion of the main loop between the first connection point and the sixth connection point is devoid of a refrigerant accumulation device.

The refrigerant circuit includes a single refrigerant accumulation device.
The use of a single refrigerant accumulation device reduces the pressure drop in the circuit, particularly in operating modes where the second exchanger operates as a refrigerant evaporator.

According to one embodiment of the thermal conditioning system, the first expansion valve is jointly arranged on the main loop and on the second branch, and is configured to:
- expanding the refrigerant fluid coming from the first heat exchanger,
- selectively direct the expanded refrigerant either to the second exchanger or to the fifth connection point.

The third connection point is part of the first regulator.

A section of refrigerant flow through the first expansion valve can vary between a maximum opening position in which the refrigerant flows through the first expansion valve without undergoing expansion, and a minimum opening position.

A cross-section of the refrigerant flow through the first expansion valve can vary continuously between the maximum opening position and the minimum opening position.

According to one embodiment of the thermal conditioning system, the second expansion valve is jointly arranged on the main loop and on the first branch, and is configured to:
- either by expanding the refrigerant from the sixth connection point and directing the expanded refrigerant to the third heat exchanger, while simultaneously blocking the refrigerant flow in the first bypass branch,
- either allow refrigerant flow in the first branch of the bypass towards the third exchanger, while simultaneously blocking refrigerant flow between the sixth connection point and the third exchanger.

The second connection point is part of the second regulator.

A section of refrigerant flow through the second expansion valve can vary between a maximum opening position in which the refrigerant flows through the second expansion valve without undergoing expansion, and a minimum opening position.

A cross-section of the refrigerant flow through the second expansion valve can vary continuously between the maximum opening position and the minimum opening position.

The first exchanger is configured to operate as a high-pressure refrigerant condenser.

According to one embodiment, the first heat exchanger is configured to exchange heat with an internal airflow.

According to one embodiment, the first heat exchanger is configured to exchange heat with a heat transfer fluid circulating in a closed heat transfer fluid circuit, the heat transfer fluid circuit comprising a heat exchanger configured to exchange heat with an internal airflow.

The second exchanger is configured to operate selectively as a refrigerant fluid evaporator or as a refrigerant fluid condenser.

The third exchanger is configured to operate as a refrigerant fluid evaporator.

According to one example of the implementation of the thermal conditioning system, the third exchanger is thermally coupled with an element of an electric powertrain of the vehicle.

The third exchanger is thermally coupled to an element of an electric powertrain of the vehicle via a heat transfer fluid circulating in a heat transfer fluid circuit.

According to one embodiment, the element of the vehicle's electric powertrain includes an electrical energy storage battery.

In one variant, or as a complement, the element of the vehicle's electric powertrain includes an electric vehicle traction motor.

Alternatively, or as a complement, the element of the vehicle's electric powertrain may include an electronic control unit for the vehicle's electric traction motor.

The heat transfer fluid circuit may include an electric heating device configured to heat the heat transfer fluid circulating in the circuit.

The fourth exchanger is configured to operate as a refrigerant fluid evaporator.

According to one embodiment of the thermal conditioning system, the main loop includes an internal heat exchanger configured to allow heat exchange between:
- the refrigerant circulating between the second heat exchanger and the second expansion valve, and
- the refrigerant fluid circulating downstream of the accumulation device and upstream of a compressor inlet.

The internal exchanger includes a first heat exchange section located on the main loop between the second exchanger and the second expansion valve, and a second heat exchange section located on the main loop downstream of the second accumulation device and upstream of the compressor inlet.

The first heat exchange section is located on the main loop downstream of the second exchanger and upstream of the sixth connection point.

The internal heat exchanger is configured to allow heat exchange between the refrigerant in the first heat exchange section and the refrigerant in the second heat exchange section.

According to an unshown variant, the internal heat exchanger is configured to allow heat exchange between:
- the refrigerant circulating in the main loop downstream of the sixth connection point and upstream of the second expansion valve, and
- the refrigerant circulating in the main loop downstream of the accumulation device and upstream of a compressor inlet.

According to another variant not shown, the internal exchanger is configured to allow heat exchange between:
- the refrigerant circulating in the third branch of the bypass between the sixth connection point and the fifth connection point, and
- the refrigerant circulating in the main loop downstream of the accumulation device and upstream of a compressor inlet.

According to yet another variant not shown, the internal exchanger is configured to allow heat exchange between:
- the refrigerant circulating in the second branch of the bypass downstream of the fifth connection point and upstream of the third expansion valve, and
- the refrigerant circulating in the main loop downstream of the accumulation device and upstream of a compressor inlet.

According to one embodiment of the thermal conditioning system, the second exchanger comprises a first heat exchange section and a second heat exchange section, and the first heat exchange section and the second heat exchange section are arranged one above the other.

According to one embodiment, the second exchanger includes a first refrigerant inlet/outlet and a second refrigerant inlet/outlet, and the first refrigerant inlet/outlet and the second refrigerant inlet/outlet are arranged on the same face of the second exchanger.

The first heat exchange section of the second exchanger includes, for example, two passes.

The second exchanger comprises a front face configured to receive the outside airflow and two side faces extending transversely to the front face.

The first refrigerant inlet/outlet and the second refrigerant inlet/outlet are located on the same side face of the second exchanger.

The invention also relates to a method of operating a thermal conditioning system as described above, in a first operating mode called " Cooling cabin and battery ".
In this first mode of operation:
- an initial flow of refrigerant circulates through the compression device where it passes under high pressure, and flows successively through the first heat exchanger without exchanging heat, through the first expansion valve without undergoing expansion, through the second heat exchanger, and is divided into:
-- a second flow of refrigerant circulating in the main loop, in the second expansion valve where it undergoes expansion and passes to a low pressure lower than the high pressure, then in the third heat exchanger where it evaporates,
-- a third flow of refrigerant circulating in the third bypass branch, then in the third expansion valve where it undergoes expansion and passes to low pressure, then in the fourth heat exchanger where it evaporates, and rejoins the refrigerant from the third heat exchanger,
The total flow formed circulates through the accumulation device and returns to the compressor.

In this first mode of operation:
- The refrigerant flow rate in the first branch of the bypass is zero.
- The refrigerant flow rate in the portion of the second branch of the bypass between the third connection point and the fifth connection point is zero.

The invention also relates to a method of operating a thermal conditioning system as described above, in a second operating mode called "heat pump and energy recovery ".
In this second mode of operation:
- a flow of refrigerant circulates in the compression device where it passes to high pressure, and circulates successively in the first exchanger where it gives up heat, in the first expansion valve where it undergoes expansion and passes to a low pressure lower than the high pressure, in the third bypass branch, in the second exchanger where it evaporates at least in part, in the first bypass branch, in the second expansion valve without undergoing expansion, in the third exchanger where it evaporates at least in part, then in the refrigerant accumulation device and returns to the compressor.

In this second mode of operation:
- The refrigerant flow rate in the second bypass branch is zero.
- The refrigerant flow rate in the portion of the main loop between the third connection point and the first connection point is zero.
- The refrigerant flow rate in the portion of the main loop between the sixth connection point and the second connection point is zero.

The invention also relates to a method of operating a thermal conditioning system as described above, in a third operating mode called " first dehumidification mode ".
In this third mode of operation:
- a flow of refrigerant circulates in the compression device where it passes to high pressure, and circulates successively in the first exchanger where it gives up heat, in the first expansion valve where it undergoes expansion and passes to an intermediate pressure lower than the high pressure, in the second exchanger, in the third bypass branch, in the third expansion valve where it undergoes expansion and passes to a low pressure lower than the intermediate pressure, in the fourth exchanger where it evaporates, then in the refrigerant accumulation device and returns to the compressor.

In this third mode of operation:
- The refrigerant flow rate in the first branch of the bypass is zero.
- The flow rate of refrigerant in the third exchanger is zero.
- The refrigerant flow rate in the portion of the main loop between the sixth connection point and the fourth connection point is zero.
- The refrigerant flow rate in the portion of the second branch of the bypass between the third connection point and the fifth connection point is zero.

The invention also relates to a method of operating a thermal conditioning system as described above, in a fourth operating mode called " second dehumidification mode " .
In this fourth mode of operation:
- a first flow of refrigerant circulates in the compression device where it passes through high pressure, and circulates successively in the first heat exchanger where it releases heat, in the first expansion valve without undergoing expansion, in the second bypass branch, and divides into:
-- a second flow of refrigerant circulating in the second bypass branch, successively in the third expansion valve where it undergoes expansion and passes to a low pressure lower than the high pressure, then in the fourth heat exchanger where it evaporates, and
-- a third flow of refrigerant circulating in the third bypass branch, then in the second expansion valve where it undergoes expansion and drops to low pressure, then in the third heat exchanger where it evaporates, and rejoins the refrigerant from the fourth heat exchanger,
The total flow formed circulates through the accumulation device and returns to the compressor.

In this fourth mode of operation:
- The flow rate of refrigerant in the second exchanger is zero.
- The refrigerant flow rate in the portion of the main loop between the third connection point and the sixth connection point is zero.
- The refrigerant flow rate in the first branch of the bypass is zero.

The invention also relates to a method of operating a thermal conditioning system as described above, in a fifth operating mode called " third dehumidification mode ".
In this fifth mode of operation:
- a flow of refrigerant fluid circulates in the compression device where it passes to high pressure, and circulates successively in the first exchanger where it gives up heat, in the first expansion valve without undergoing expansion, then in the second bypass branch, successively in the third expansion valve where it undergoes expansion and passes to a low pressure lower than the high pressure, in the fourth exchanger where it evaporates, then in the accumulation device, and returns to the compressor.

In this fifth mode of operation:
- The flow rate of refrigerant in the second exchanger is zero.
- The flow rate of refrigerant in the third exchanger is zero.
- The refrigerant flow rate in the portion of the main loop between the third connection point and the fourth connection point is zero.
- The refrigerant flow rate in the first branch of the bypass is zero.
- The refrigerant flow rate in the third branch of the bypass is zero.

Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which:

FIG. 1 is a schematic view of one embodiment of the proposed thermal conditioning system,

FIG. 2 is a schematic view of a first variant of the implementation of the FIG. 1 ,

FIG. 3 is a schematic view of a second variant of the embodiment of the FIG. 1 ,

FIG. 4 is a schematic view of the thermal conditioning system of the FIG. 1 operating according to a first mode of operation, called passenger compartment and battery cooling mode,

FIG. 5 is a schematic view of the thermal conditioning system of the FIG. 1 operating according to a second mode of operation, known as heat pump and energy recovery mode,

FIG. 6 is a schematic view of the thermal conditioning system of the FIG. 1 operating according to a third mode of operation, known as the first dehumidification mode,

FIG. 7 is a schematic view of the thermal conditioning system of the FIG. 1 operating according to a fourth mode of operation, known as the second dehumidification mode,

FIG. 8 is a schematic view of the thermal conditioning system of the FIG. 1 operating according to a fifth mode of operation, known as the third dehumidification mode,

FIG. 9 is a schematic view detailing part of the proposed thermal conditioning system.

To facilitate the reading of the figures, the different elements are not necessarily drawn to scale. In these figures, identical elements have the same reference numbers. Some elements or parameters may be indexed, that is, designated, for example, as first element or second element, or first parameter and second parameter, etc. This indexing aims to differentiate between similar, but not identical, elements or parameters. This indexing does not imply any priority of one element or parameter over another, and the designations can be interchanged.

In the following description, the expression "a first element upstream of a second element" means that the first element is located before the second element relative to the direction of flow, or path, of a fluid. Similarly, the term "a first element downstream of a second element" means that the first element is located after the second element relative to the direction of flow, or path, of the fluid in question. In the case of a refrigerant circuit, the term "a first element upstream of a second element" means that the refrigerant flows successively through the first element, then the second element, without passing through the compression device. In other words, the refrigerant exits the compression device, possibly passes through one or more elements, then passes through the first element, then the second element, and then returns to the compression device, possibly after passing through other elements.

The expression "a second element is placed between a first element and a third element" means that the shortest path to go from the first element to the third element passes through the second element.

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

The thermal conditioning system 100 described below includes an electronic control unit (not shown) that receives information from various sensors, notably those measuring the characteristics of the refrigerant at different points in the circuit. The electronic control unit also receives commands from the vehicle occupants, such as the desired cabin temperature. It can also receive commands from other electronic subsystems, such as the battery management system. The electronic control unit implements control laws to operate the various actuators, ensuring that the thermal conditioning system 100 is controlled in a way that maintains the received commands.

A compression device 7 allows a refrigerant to circulate within a refrigerant circuit 10. The refrigerant circuit 10 forms a closed loop through which the refrigerant can circulate. The refrigerant circuit 10 is leak-proof when it is in its nominal operating condition, that is, without any faults or leaks. Each connection point of the circuit 10 allows the refrigerant to flow into one of the circuit sections that converge at that connection point. The distribution of the refrigerant between the circuit sections that converge at a connection point is achieved by opening or closing the shut-off valves, check valves, or expansion devices located on each of these sections. In other words, each connection point is a means of redirecting the refrigerant arriving at that connection point. Various shut-off valves and check valves thus allow the refrigerant to be selectively directed into the different branches of the refrigerant circuit, in order to ensure different modes of operation, as will be described later.

The refrigerant used by the refrigerant circuit 10 is a chemical refrigerant such as R1234yf or R134a. A natural refrigerant, such as R290 or R744, can also be used.

The heat transfer fluid circuit(s) also form one or more closed and sealed circuits in which a heat transfer fluid can circulate. The heat transfer fluid can exchange heat during its circulation.

The term "interior airflow Fi" refers to the airflow directed towards the passenger compartment of a motor vehicle. This interior airflow Fi may circulate within a heating, ventilation, and/or air conditioning (HVAC) system. This system is not shown in the various figures. A first fan-motor unit, also not shown, is located within the HVAC system to increase the flow rate of the interior airflow Fi if necessary.

The term "external airflow Fe" refers to airflow that is not directed into the vehicle's passenger compartment. In other words, this airflow Fe remains outside the vehicle's passenger compartment. A second fan motor unit, also not shown, can be activated to increase the external airflow Fe if necessary. The airflow provided by both the first and second fan motor units can be adjusted in real time according to heat exchange requirements, for example, by the electronic control unit of the climate control system 100.

The term "first exchanger" is equivalent to the term "first heat exchanger." Similarly, the term "internal exchanger" is equivalent to the term "internal heat exchanger." The term "storage device" is equivalent to the term "refrigerant storage device."

There FIG. 1 schematically represents a thermal conditioning system 100 for a motor vehicle.
The thermal conditioning system 100 includes a refrigerant circuit 10 configured to circulate a refrigerant.
The refrigerant circuit 10 comprises a main loop A consisting successively, according to the direction of refrigerant flow:
- a 7-inch compressor,
- a first heat exchanger 1 thermally coupled to an internal airflow Fi in the passenger compartment of a motor vehicle,
- a first regulator 21,
- a second heat exchanger 2 thermally coupled to an external airflow Fe to the passenger compartment of the motor vehicle,
- a second 22 regulator,
- a third heat exchanger 3.
The refrigerant fluid circuit 10 includes a first branch B connecting a first connection point 11 located on the main loop A downstream of the first expansion valve 21 and upstream of the second exchanger 2 to a second connection point 12 located on the main loop A downstream of the second heat exchanger 2 and upstream of the third exchanger 3.
The refrigerant circuit 10 includes a second branch C connecting a third connection point 13 located on the main loop A downstream of the first heat exchanger 1 and upstream of the second heat exchanger 2 to a fourth connection point 14 located on the main loop A downstream of the third heat exchanger 3 and upstream of the compressor 7. The second branch C includes successively a third expansion valve 23 and a fourth heat exchanger configured to exchange heat with the indoor airflow Fi.
The refrigerant circuit 10 includes a third branch D connecting a fifth connection point 15 located on the second branch C between the third connection point 13 and the third expansion valve 23 to a sixth connection point 16 located on the main loop A downstream of the second exchanger 2 and upstream of the second expansion valve 22.

This refrigerant circuit architecture allows for numerous different operating modes. Furthermore, this architecture allows the refrigerant to flow through the second heat exchanger 2 in opposite directions depending on whether this exchanger is operating as an evaporator or a condenser. This makes it possible to optimize the design of the second heat exchanger 2 to achieve better heat exchange performance than when the flow direction remains the same for both condensation and evaporation modes.

The main loop A includes a refrigerant fluid accumulation device 6 located downstream of the third exchanger 3 and upstream of an inlet 7a of the compressor 7.

More specifically, the refrigerant fluid accumulation device 6 is arranged between the fourth connection point 14 and the inlet 7a of the compressor 7.

The portion of the main loop A between the first connection point 11 and the sixth connection point 16 is devoid of a refrigerant fluid accumulation device 6.

The accumulation device 6 makes it possible to compensate for variations, depending on the operating mode used and the thermal operating conditions, in the mass of refrigerant circulating in the refrigerant circuit 10.
The accumulation device 6 is a refrigerant fluid accumulator.

According to the illustrated example, the refrigerant circuit 10 includes a single refrigerant accumulation device.
The use of a single refrigerant fluid storage device 6 reduces the pressure drop in the circuit, particularly in operating modes where the second exchanger 2 operates as a refrigerant fluid evaporator.

The first pressure regulator 21 is jointly arranged on the main loop A and on the second branch C, and is configured to:
- to expand the refrigerant fluid coming from the first heat exchanger 1,
- selectively direct the expanded refrigerant either to the second exchanger 2, or to the fifth connection point 15.

The third connection point 13 is part of the first regulator 21.

A section of the refrigerant fluid passing through the first expansion valve 21 can vary between a maximum opening position in which the refrigerant fluid passes through the first expansion valve 21 without undergoing expansion, and a minimum opening position.

A cross-section of the refrigerant fluid passing through the first expansion valve 21 can vary continuously between the maximum opening position and the minimum opening position.

The first regulator 21 is a three-way valve that can jointly provide controlled decompression.
The first expansion valve 21 includes a refrigerant inlet and two refrigerant outlets.
The first expansion valve 21 can supply expanded refrigerant at the first outlet or at the second outlet, simultaneously closing the other outlet.
Communication between the inlet and one of the outlets of the first regulator 21 is always maintained. The two outlets of the first regulator 21 cannot be simultaneously closed.
The expansion rate achieved at the outlet supplying the refrigerant can vary continuously, from zero expansion to maximum expansion.

The second regulator 22 is jointly connected to the main loop A and the first branch B, and is configured to:
- either expand the refrigerant fluid coming from the sixth connection point 16 and direct the expanded refrigerant fluid towards the third exchanger 3, while simultaneously blocking the circulation of refrigerant fluid in the first branch of the bypass B,
- either allow refrigerant flow in the first branch of bypass B towards the third exchanger 3, while jointly blocking refrigerant flow between the sixth connection point 16 and the third exchanger 3.

The second regulator 22 is a three-way valve that can jointly provide controlled decompression.

The second connection point 12 is part of the second regulator 22.

A section of the refrigerant fluid passing through the second expansion valve 22 can vary between a maximum opening position in which the refrigerant fluid passes through the second expansion valve 22 without undergoing expansion, and a minimum opening position.

A cross-section of the refrigerant fluid passing through the second expansion valve 22 can vary continuously between the maximum opening position and the minimum opening position.

The second expansion valve 22 is a three-way valve that can jointly provide controlled expansion of the refrigerant.
As with the first expansion valve 21, the second expansion valve 22 includes a refrigerant inlet and two refrigerant outlets.
The second expansion valve 22 can supply expanded refrigerant at the first outlet or at the second outlet, simultaneously closing the other outlet.

The second regulator 22, like the first regulator 21, includes for example a rotating movable obturator in the shape of a sphere having an internal recess forming an internal fluid circulation conduit.
The hollow comprises a first portion extending radially from the periphery of the sphere to the center of the sphere. The hollow comprises a second portion extending perpendicularly from the first portion. This second portion extends radially from the center of the sphere to the periphery of the sphere.
The second portion and the first portion are, for example, perpendicular.
The movable shutter is arranged in a body forming three refrigerant circulation channels. The movable shutter separates the different fluid circulation channels and can be moved by a control mechanism.
The movable shutter forms a fluid passage opening whose effective section is controlled by the angular position of the movable shutter.
The first expansion valve 21 and the second expansion valve 22 are electronic expansion valves. An electronic control module drives an electric motor that moves the movable damper, controlling the cross-sectional area of the refrigerant flow. This allows for real-time, closed-loop control of the damper's position.

Similarly, the third regulator 23 can be an electronic regulator. The third regulator 23 is a two-way type, meaning it has exactly one inlet and one outlet.
The minimum opening position of the third expansion valve 23 is a closed position, i.e. the third expansion valve 23 can interrupt the circulation of refrigerant fluid in the second branch of bypass C.

We will now describe the role of the different heat exchangers.

The first exchanger 1 is configured to operate as a high-pressure refrigerant condenser.

Thermal coupling between the first exchanger 1 and the indoor airflow Fi can be ensured in different ways.

According to the illustrated embodiment and its first variant, the first heat exchanger 1 is configured to exchange heat with an internal airflow Fi.
The thermal coupling is then said to be direct.
The first exchanger 1 thus allows the interior airflow Fi to be heated, and thus the passenger compartment of the vehicle.
The first heat exchanger 1 is located in the vehicle's heating, ventilation and/or air conditioning system.

According to the second variant, illustrated on the FIG. 3 , the first heat exchanger 1 is configured to exchange heat with a heat transfer fluid circulating in a closed heat transfer fluid circuit 30, the heat transfer fluid circuit 30 comprising a heat exchanger 1A configured to exchange heat with an internal airflow Fi.

The thermal coupling is then said to be indirect.
The heat transfer fluid is, for example, a mixture of water and glycol.
A circulation pump, not shown, allows the heat transfer fluid to circulate in circuit 30.
In this case, it is the heat exchanger 1A, also known as the heater radiator, which is located in the vehicle's heating, ventilation and/or air conditioning system.

The second exchanger 2 is configured to operate selectively as a refrigerant fluid evaporator or as a refrigerant fluid condenser.
The second exchanger 2 can indeed, depending on the operating modes, receive high pressure and high temperature refrigerant, or low pressure refrigerant.
The second exchanger 2 is for example located in the front of the vehicle, in order to receive the outside airflow Fe.
The second interchanger 2 thus receives the airflow resulting from the advance of the vehicle, as well as the airflow created by the second motor-fan unit.

The third exchanger 3 is configured to operate as a refrigerant fluid evaporator.
The third exchanger 3 can receive low-pressure refrigerant.

According to the illustrated example, the third exchanger 3 is thermally coupled with an element 25 of an electric drive chain of the vehicle.

The third heat exchanger 3 is here thermally coupled with an element 25 of an electric drive chain of the vehicle via a heat transfer fluid circulating in a heat transfer fluid circuit 20.
Circuit 20 includes a circulation pump, not shown, which circulates the heat transfer fluid. The pump is, for example, an electrically controlled pump that can be selectively activated or deactivated.
The heat transfer fluid can be a mixture of water and glycol.

According to one embodiment, element 25 of the vehicle's electric drivetrain includes an electrical energy storage battery.
According to one variant, or in a complementary manner, element 25 of the vehicle's electric drive chain includes an electric vehicle traction motor.
Alternatively, or as a complement, element 25 of the vehicle's electric drive chain may include an electronic control unit for the vehicle's electric traction motor.

The heat transfer fluid circuit 20 may include an electric heating device, not shown in the figures. The electric heating device is configured to heat the heat transfer fluid circulating in the circuit.

The fourth exchanger 4 is configured to operate as a refrigerant fluid evaporator.
The fourth exchanger 4 can receive low-pressure refrigerant.
The fourth exchanger 4 thus allows the internal airflow Fi to be cooled, and therefore the passenger compartment of the vehicle.
The fourth heat exchanger 4, called the passenger compartment evaporator, is located in the vehicle's heating, ventilation and/or air conditioning system. The fourth heat exchanger 4 is located upstream of the first heat exchanger 1 according to the direction of the interior airflow Fi.

According to the first variant of the thermal conditioning system100, illustrated in the FIG. 2 The main loop A includes an internal heat exchanger 9 configured to allow heat exchange between:
- the refrigerant circulating between the second heat exchanger 2 and the second expansion valve 22, and
- the refrigerant fluid circulating downstream of the accumulation device 6 and upstream of an inlet 7a of the compressor 7.

The internal exchanger 9 includes a first heat exchange section 9a arranged on the main loop A between the second exchanger 2 and the second expansion valve 22, and a second heat exchange section 9b arranged on the main loop A downstream of the second storage device 6 and upstream of the inlet 7a of the compressor 7.

The first heat exchange section 9a is located on the main loop A downstream of the second exchanger 2 and upstream of the sixth connection point 16.

The internal heat exchanger 9 is configured to allow heat exchange between the refrigerant in the first heat exchange section 9a and the refrigerant in the second heat exchange section 9b.

The internal heat exchanger can be combined with the second variant, illustrated on the FIG. 3 .
The internal exchanger 9 allows the enthalpy variation during the thermodynamic cycle to be increased, and thus its efficiency.

According to an unshown variant, the internal heat exchanger 9 is configured to allow heat exchange between:
- the refrigerant circulating in the main loop A downstream of the sixth connection point 16 and upstream of the second expansion valve 22, and
- the refrigerant circulating in the main loop A downstream of the accumulation device 6 and upstream of an inlet 7a of the compressor 7.

According to another variant not shown, the internal exchanger 9 is configured to allow heat exchange between:
- the refrigerant circulating in the third branch of the bypass D between the sixth connection point 16 and the fifth connection point 15, and
- the refrigerant circulating in the main loop A downstream of the accumulation device 6 and upstream of an inlet 7a of the compressor 7.

According to yet another variant not shown, the internal exchanger 9 is configured to allow heat exchange between:
- the refrigerant circulating in the second branch of the bypass C downstream of the fifth connection point 15 and upstream of the third expansion valve 23, and
- the refrigerant circulating in the main loop A downstream of the accumulation device 6 and upstream of an inlet 7a of the compressor 7.

According to one embodiment of the thermal conditioning system 100, detailed schematically on the FIG. 9 , the second exchanger 2 includes a first heat exchange section 2A and a second heat exchange section 2B.
The first heat exchange section 2A and the second heat exchange section 2B are arranged one above the other.
It is understood that the first heat exchange section 2A and the second heat exchange section 2B are above each other when the second exchanger 2 is in nominal installation position.

The second heat exchanger 2 comprises a first refrigerant inlet/outlet 2-1 and a second refrigerant inlet/outlet 2-2. The first refrigerant inlet/outlet 2-1 and the second refrigerant inlet/outlet 2-2 are located on the same face F2 of the second heat exchanger 2.

The first heat exchange section 2A of the second exchanger 2 includes, for example, two passes.

The second exchanger 2 comprises a front face F1 configured to receive the outside air flow Fe and two side faces F2, F3 extending transversely to the front face.
The first refrigerant inlet/outlet 2-1 and the second refrigerant inlet/outlet 2-2 are arranged on the same side face F2 of the second exchanger 2.

Figures 4 to 8 illustrate the operation of the thermal conditioning system 100 of the FIG. 1 according to different operating modes.
In these figures, the portions of circuit 10 in which a flow of refrigerant fluid circulates are in thick solid line, while the portions in which the refrigerant fluid does not circulate are in thin dashed lines.
The different arrows indicate the direction of flow of the refrigerant fluid in the different portions of the refrigerant circuit 10.

In steady state, the time variation of the mass of refrigerant in a heat exchanger is zero, and the flow rate of refrigerant downstream of a heat exchanger is equal to the flow rate of refrigerant upstream of that heat exchanger.
Similarly, there is no accumulation of refrigerant in an expansion valve, and the flow rate of refrigerant downstream of an expansion valve is equal to the flow rate upstream of that expansion valve.

There FIG. 4 diagrams a process of operation of a thermal conditioning system as described above, in a first mode of operation called " Cooling of passenger compartment and battery ".
In this first mode of operation:
- a first flow Qr1 of refrigerant circulates in the compression device 7 where it passes through high pressure, and circulates successively in the first exchanger 1 without exchanging heat, in the first expansion valve 21 without undergoing expansion, in the second exchanger 2, and divides into:
-- a second flow Qr2 of refrigerant circulating in the main loop A, in the second expansion valve 22 where it undergoes expansion and passes to a low pressure lower than the high pressure, then in the third heat exchanger 3 where it evaporates,
-- a third flow Qr3 of refrigerant circulating in the third branch of bypass D, then in the third expansion valve 23 where it undergoes expansion and passes to low pressure, then in the fourth exchanger 4 where it evaporates, and joins the refrigerant from the third exchanger 3.
The total flow formed circulates in the accumulation device 6 and returns to the compressor 7.

In this first mode of operation:
- The flow rate of refrigerant fluid in the first branch of bypass B is zero.
- The refrigerant flow rate in the portion of the second branch of the bypass C between the third connection point 13 and the fifth connection point 15 is zero.

The interior airflow Fi is cooled at the fourth heat exchanger 4 due to the evaporation of the refrigerant circulating in this heat exchanger. The vehicle's passenger compartment is thus cooled.
The heat transfer fluid in the heat transfer fluid circuit 20 is cooled at the third heat exchanger 3 due to the evaporation of the refrigerant circulating in this exchanger. The component 25 of the electric traction system is thus cooled.
The heat of desuperheating and condensation of the refrigerant discharged at high pressure by the compressor 7 is dissipated in the outside airflow Fe at the level of the second exchanger 2.
The second heat exchanger 2, which operates as a high-pressure refrigerant condenser, carries the refrigerant from the first inlet/outlet 2-1 to the second inlet/outlet 2-2. The direction of refrigerant flow in the second heat exchanger 2 is indicated by the symbol S1 on the FIG. 4 as well as on the FIG. 9 .
There is no heat exchange at the first heat exchanger 1, because the airflow over the first heat exchanger 1 is zero. Therefore, a movable flap, not shown, can close off the surface of the first heat exchanger 1.

The first expansion valve 21 directs the refrigerant from the first exchanger 1 to the second exchanger 2, and blocks the circulation of refrigerant to the second branch of the bypass C.
The second expansion valve 22 blocks circulation in the first branch of the bypass B, from the first connection point 11 to the second connection point 12. The second expansion valve 22 expands the refrigerant coming from the sixth connection point 16 and directs it to the third exchanger 3.
The refrigerant from the third exchanger 3 and the refrigerant from the fourth exchanger 4 meet at the fourth connection point 14.

There FIG. 5 diagram illustrates a process of operation of a thermal conditioning system as described previously, in a second mode of operation called " heat pump and energy recovery ".
In this second mode of operation:
- a flow Qr of refrigerant circulates in the compression device 7 where it passes to high pressure, and circulates successively in the first exchanger 1 where it gives up heat, in the first expansion valve 21 where it undergoes expansion and passes to a low pressure lower than the high pressure, in the third branch of bypass D, in the second exchanger 2 where it evaporates at least in part, in the first branch of bypass B, in the second expansion valve 22 without undergoing expansion, in the third exchanger 3 where it evaporates at least in part, then in the refrigerant accumulation device 6 and returns to the compressor 7.

In this second mode of operation:
- The flow rate of refrigerant fluid in the second branch of the bypass C is zero.
For this, the third regulator 23 is in the closed position.
The refrigerant flow rate in the fourth heat exchanger 4 is therefore zero. The fourth heat exchanger 4 is thermally inactive, meaning it does not perform any heat exchange.
- The refrigerant flow rate in the portion of the main loop A between the third connection point 13 and the first connection point 11 is zero.
The first expansion valve 21 expands the refrigerant from the first exchanger 1 and directs it to the second branch of the bypass C, while blocking circulation in the main loop A towards the first connection point 11.
- The refrigerant flow rate in the portion of the main loop A between the sixth connection point 16 and the second connection point 12 is zero.
The second expansion valve 22 blocks the circulation from the sixth connection point 16 to the second connection point 12, and directs the refrigerant from the first connection point 11 to the third exchanger 3.
At the sixth connection point 16, the refrigerant fluid from the third branch of the bypass D is directed to the second exchanger 2.

In this second operating mode, the interior airflow Fi is heated at the first heat exchanger 1 due to the desuperheating and condensation of the refrigerant circulating at high pressure in this heat exchanger. The vehicle's passenger compartment is thus heated.
The heat of vaporization of the refrigerant during the thermodynamic cycle is supplied partly by the outside air flow Fe at the level of the second exchanger 2 and partly by the heat transfer fluid of the circuit 20 at the level of the third exchanger 3. In other words, the heat losses of the element 25 of the traction chain, which are dissipated in the heat transfer fluid of the circuit 20, are at least partly recovered and contribute to the heating of the passenger compartment.

The second heat exchanger 2, which operates as an evaporator, carries the refrigerant from the second inlet/outlet 2-2 to the first inlet/outlet 2-1. The direction of refrigerant flow in the second heat exchanger 2 is indicated by the symbol S2 on the FIG. 4 and on the FIG. 9 .
In other words, the direction of circulation of the refrigerant fluid in the second exchanger 2 is reversed compared to the previous operating mode.
The efficiency of the second exchanger 2 can thus be optimized, because the compromises traditionally required between condenser operation and evaporator operation, according to a single direction of refrigerant flow, can be avoided here.

Similarly, the direction of refrigerant flow in the third branch D is reversed compared to the previous operating mode.
In steady state, the flow rate of refrigerant fluid is identical in the first exchanger 1, the second exchanger 2 and the third exchanger 3, which are traversed in series in that order.

There FIG. 6 diagrams a process of operation of a thermal conditioning system as described above, in a third mode of operation called " first mode of dehumidification ".
In this third mode of operation:
- a flow Qr of refrigerant circulates in the compression device 7 where it passes to high pressure, and circulates successively in the first exchanger 1 where it gives up heat, in the first expansion valve 21 where it undergoes expansion and passes to an intermediate pressure lower than the high pressure, in the second exchanger 2, in the third bypass branch D, in the third expansion valve 23 where it undergoes expansion and passes to a low pressure lower than the intermediate pressure, in the fourth exchanger 4 where it evaporates, then in the refrigerant accumulation device 6 and returns to the compressor 7.

In this third mode of operation:
- The flow rate of refrigerant fluid in the first branch of bypass B is zero.
- The flow rate of refrigerant fluid in the third exchanger 3 is zero.
The third exchanger 3 therefore does not perform heat exchange, that is to say it is thermally inactive.
- The refrigerant flow rate in the portion of the main loop A between the sixth connection point 16 and the fourth connection point 14 is zero.
- The flow rate of refrigerant fluid in the portion of the second branch of the bypass C between the third connection point 13 and the fifth connection point 15 is zero.

In this third operating mode, the indoor airflow Fi is cooled at the fourth heat exchanger 4 by the evaporation of the low-pressure refrigerant, and heated at the first heat exchanger 1 by the desuperheating and condensation of the high-pressure refrigerant. The indoor airflow Fi is thus dehumidified.
The intermediate pressure refrigerant gives up heat to the outside airflow Fe at the level of the second exchanger 2.
The heat of condensation of the refrigerant is thus dissipated partly in the indoor airflow Fi at the level of the first exchanger 1 and partly in the outdoor airflow Fe at the level of the second exchanger 2.
Controlling the expansion rate achieved by the first expansion valve 21 and the expansion rate achieved by the third exchanger 3 allows adjusting the distribution of the thermal power dissipated at the level of the second exchanger 2 and the thermal power dissipated at the level of the fourth exchanger 4.
The first interchange 1, the second interchange 2 and the fourth interchange 4 are traversed in series in that order.
In steady state, the refrigerant flow rate is the same in the fourth exchanger 4, in the first exchanger 1 and in the second exchanger 2.

The second heat exchanger 2, which operates as an intermediate-pressure refrigerant condenser, is traversed by the refrigerant in the direction from the first inlet/outlet 2-1 to the second inlet/outlet 2-2, as indicated on the FIG. 6 by the sign S1.

There FIG. 7 diagrams a process of operation of a thermal conditioning system as described above, in a fourth mode of operation called " second mode of dehumidification ".
In this fourth mode of operation:
- a first flow Qr1 of refrigerant fluid circulates in the compression device 7 where it passes through high pressure, and circulates successively in the first exchanger 1 where it releases heat, in the first expansion valve 21 without undergoing expansion, in the second bypass branch C, and divides into:
-- a second flow Qr2 of refrigerant circulating in the second branch of the bypass C, successively in the third expansion valve 23 where it undergoes expansion and passes to a low pressure lower than the high pressure, then in the fourth heat exchanger 4 where it evaporates, and
-- a third flow Qr3 of refrigerant circulating in the third branch of bypass D, then in the second expansion valve 22 where it undergoes expansion and passes to low pressure, then in the third exchanger 3 where it evaporates, and joins the refrigerant from the fourth exchanger 4.
The total flow formed circulates in the accumulation device 6 and returns to the compressor 7.

In this fourth mode of operation:
- The flow rate of refrigerant fluid in the second exchanger 2 is zero.
- The refrigerant flow rate in the portion of the main loop A between the third connection point 13 and the sixth connection point 16 is zero.
- The flow rate of refrigerant fluid in the first branch of bypass B is zero.
The first expansion valve 21 directs the refrigerant from the first heat exchanger 1 to the second branch line C, without expanding it. The first expansion valve 21 also blocks circulation in the main loop A to the first connection point 11.
The second expansion valve 22 expands the refrigerant fluid coming from the third branch branch D and then from the sixth connection point 16, and directs it to the third exchanger 3. The circulation from the first connection point 11 to the second connection point 12 is jointly blocked.

In this fourth operating mode, the indoor airflow Fi is cooled at the fourth heat exchanger 4 by the evaporation of the low-pressure refrigerant, and heated at the first heat exchanger 1 by the desuperheating and condensation of the high-pressure refrigerant. The indoor airflow Fi is thus dehumidified.
The heat of condensation of the high-pressure refrigerant is dissipated into the internal airflow Fi at the level of the first exchanger 1.
The heat required for the evaporation of the low-pressure refrigerant is supplied partly by the internal airflow Fi at the level of the fourth exchanger 4, and partly by the heat transfer fluid of the circuit 20 at the level of the third exchanger 3.
The low-pressure refrigerant circulates in parallel in the third exchanger 3 and in the fourth exchanger 4.
The high-pressure refrigerant flow rate in the first exchanger 1 is greater than the low-pressure refrigerant flow rate in the third exchanger 3.
The second exchanger 2 is thermally inactive.

There FIG. 8 diagrams a process of operation of a thermal conditioning system as described above, in a fifth mode of operation called " third mode of dehumidification ".
In this fifth mode of operation:
- a flow Qr of refrigerant fluid circulates in the compression device 7 where it passes to high pressure, and circulates successively in the first exchanger 1 where it gives up heat, in the first expansion valve 21 without undergoing expansion, then in the second bypass branch C, successively in the third expansion valve 23 where it undergoes expansion and passes to a low pressure lower than the high pressure, in the fourth exchanger 4 where it evaporates, then in the accumulation device 6, and returns to the compressor 7.

In this fifth mode of operation:
- The flow rate of refrigerant fluid in the second exchanger 2 is zero.
- The flow rate of refrigerant fluid in the third exchanger 3 is zero.
- The refrigerant flow rate in the portion of the main loop A between the third connection point 13 and the fourth connection point 14 is zero.
- The flow rate of refrigerant fluid in the first branch of bypass B is zero.
- The refrigerant flow rate in the third branch of the bypass D is zero.

In this fifth operating mode, the indoor airflow Fi is cooled at the fourth heat exchanger 4 by the evaporation of the low-pressure refrigerant, and heated at the first heat exchanger 1 by the desuperheating and condensation of the high-pressure refrigerant. The indoor airflow Fi is thus dehumidified.
The heat from desuperheating and condensation of the refrigerant is dissipated into the internal airflow Fi at the level of the first exchanger 1.
The heat required for the evaporation of the low-pressure refrigerant is also supplied by the internal airflow Fi at the level of the fourth exchanger 4.
In steady state, the flow rate of high-pressure refrigerant in the first exchanger 1 is equal to the flow rate of low-pressure refrigerant in the fourth exchanger 4.
The second exchanger 2 and the third exchanger 3 are thermally inactive.

Claims (13)

Thermal conditioning system (100) for a motor vehicle, comprising a refrigerant circuit (10) configured to circulate a refrigerant, the refrigerant circuit (10) comprising:
- a main loop (A) comprising successively, according to the direction of refrigerant flow:
-- a compressor (7),
-- a first heat exchanger (1) thermally coupled to an interior airflow (Fi) in the passenger compartment of a motor vehicle,
-- a first regulator (21),
-- a second heat exchanger (2) thermally coupled to an outside airflow (Fe) to the passenger compartment of the motor vehicle,
-- a second regulator (22),
-- a third heat exchanger (3),
- a first branch branch (B) connecting a first connection point (11) located on the main loop (A) downstream of the first expansion valve (21) and upstream of the second exchanger (2) to a second connection point (12) located on the main loop (A) downstream of the second heat exchanger (2) and upstream of the third exchanger (3),
- a second branch branch (C) connecting a third connection point (13) located on the main loop (A) downstream of the first exchanger (1) and upstream of the second exchanger (2) to a fourth connection point (14) located on the main loop (A) downstream of the third exchanger (3) and upstream of the compressor (7), the second branch branch (C) comprising successively a third expansion valve (23) and a fourth heat exchanger configured to exchange heat with the indoor airflow (Fi),
- a third branch branch (D) connecting a fifth connection point (15) located on the second branch branch (C) between the third connection point (13) and the third regulator (23) to a sixth connection point (16) located on the main loop (A) downstream of the second exchanger (2) and upstream of the second regulator (22). Thermal conditioning system (100) according to claim 1, in which the main loop (A) includes a refrigerant fluid accumulation device (6) disposed downstream of the third exchanger (3) and upstream of an inlet (7a) of the compressor (7). Thermal conditioning system (100) according to claim 1 or 2, wherein the first expansion valve (21) is arranged jointly on the main loop (A) and on the second bypass branch (C), and is configured to:
- expanding the refrigerant fluid coming from the first heat exchanger (1),
- selectively direct the expanded refrigerant either to the second exchanger (2), or to the fifth connection point (15). Thermal conditioning system (100) according to any one of the preceding claims, wherein the second expansion valve (22) is jointly arranged on the main loop (A) and on the first bypass branch (B), and is configured to:
- either expand the refrigerant fluid coming from the sixth connection point (16) and direct the expanded refrigerant fluid towards the third exchanger (3), while simultaneously blocking the circulation of refrigerant fluid in the first bypass branch (B),
- either allow refrigerant flow in the first branch of bypass (B) towards the third exchanger (3), while jointly blocking refrigerant flow between the sixth connection point (16) and the third exchanger (3). Thermal conditioning system (100) according to any one of the preceding claims, wherein the third exchanger (3) is thermally coupled with an element (25) of an electric drive chain of the vehicle. Thermal conditioning system (100) according to any one of the preceding claims, wherein the main loop (A) comprises an internal heat exchanger (9) configured to permit heat exchange between:
- the refrigerant circulating between the second heat exchanger (2) and the second expansion valve (22), and
- the refrigerant fluid circulating downstream of the accumulation device (6) and upstream of an inlet (7a) of the compressor (7). Thermal conditioning system (100) according to any one of the preceding claims, wherein the second exchanger (2) comprises a first heat exchange section (2A) and a second heat exchange section (2B), and wherein the first heat exchange section (2A) and the second heat exchange section (2B) are arranged one above the other. Thermal conditioning system (100) according to any one of the preceding claims, wherein the second exchanger (2) comprises a first refrigerant inlet/outlet (2-1) and a second refrigerant inlet/outlet (2-2), and wherein the first refrigerant inlet/outlet (2-1) and the second refrigerant inlet/outlet (2-2) are arranged on the same face (F2) of the second exchanger (2). Method of operating a thermal conditioning system according to any one of claims 1 to 8, in a first operating mode called " Cooling of passenger compartment and battery " in which:
- a first flow (Qr1) of refrigerant fluid circulates in the compression device (7) where it passes through high pressure, and circulates successively in the first exchanger (1) without exchanging heat, in the first expansion valve (21) without undergoing expansion, in the second exchanger (2), and divides into:
-- a second flow (Qr2) of refrigerant circulating in the main loop (A), in the second expansion valve (22) where it undergoes expansion and passes to a low pressure lower than the high pressure, then in the third heat exchanger (3) where it evaporates,
-- a third flow (Qr3) of refrigerant circulating in the third bypass branch (D), then in the third expansion valve (23) where it undergoes expansion and passes to low pressure, then in the fourth exchanger (4) where it evaporates, and rejoins the refrigerant from the third exchanger (3),
The total flow formed circulates in the accumulation device (6) and returns to the compressor (7). Method of operating a thermal conditioning system according to any one of claims 1 to 8, in a second operating mode called " Heat pump and energy recovery " in which:
- a flow (Qr) of refrigerant fluid circulates in the compression device (7) where it passes to high pressure, and circulates successively in the first exchanger (1) where it gives up heat, in the first expansion valve (21) where it undergoes expansion and passes to a low pressure lower than the high pressure, in the third bypass branch (D), in the second exchanger (2) where it evaporates at least in part, in the first bypass branch (B), in the second expansion valve (22) without undergoing expansion, in the third exchanger (3) where it evaporates at least in part, then in the refrigerant fluid accumulation device (6) and returns to the compressor (7). Method of operating a thermal conditioning system according to any one of claims 1 to 8, in a third operating mode called " first dehumidification mode " in which:
- a flow (Qr) of refrigerant fluid circulates in the compression device (7) where it passes to high pressure, and circulates successively in the first exchanger (1) where it gives up heat, in the first expansion valve (21) where it undergoes expansion and passes to an intermediate pressure lower than the high pressure, in the second exchanger (2), in the third bypass branch (D), in the third expansion valve (23) where it undergoes expansion and passes to a low pressure lower than the intermediate pressure, in the fourth exchanger (4) where it evaporates, then in the refrigerant fluid accumulation device (6) and returns to the compressor (7). Method of operating a thermal conditioning system according to any one of claims 1 to 8, in a fourth operating mode called " second dehumidification mode " in which:
- a first flow (Qr1) of refrigerant fluid circulates in the compression device (7) where it passes through high pressure, and circulates successively in the first exchanger (1) where it releases heat, in the first expansion valve (21) without undergoing expansion, in the second bypass branch (C), and divides into:
-- a second flow (Qr2) of refrigerant circulating in the second bypass branch (C), successively in the third expansion valve (23) where it undergoes expansion and passes to a low pressure lower than the high pressure, then in the fourth heat exchanger (4) where it evaporates, and
-- a third flow (Qr3) of refrigerant circulating in the third bypass branch (D), then in the second expansion valve (22) where it undergoes expansion and passes to low pressure, then in the third exchanger (3) where it evaporates, and joins the refrigerant from the fourth exchanger (4),
The total flow formed circulates in the accumulation device (6) and returns to the compressor (7). Method of operating a thermal conditioning system according to any one of claims 1 to 8, in a fifth operating mode called " third dehumidification mode " in which:
- a flow (Qr) of refrigerant fluid circulates in the compression device (7) where it passes to high pressure, and circulates successively in the first exchanger (1) where it gives up heat, in the first expansion valve (21) without undergoing expansion, then in the second bypass branch (C), successively in the third expansion valve (23) where it undergoes expansion and passes to a low pressure lower than the high pressure, in the fourth exchanger (4) where it evaporates, then in the accumulation device (6), and returns to the compressor (7).