FR2991435A1 - HEATING, VENTILATION AND / OR AIR CONDITIONING INSTALLATION FOR MOTOR VEHICLE AND METHOD OF IMPLEMENTING SUCH INSTALLATION - Google Patents

Abstract

The invention relates to a heating, ventilation and / or air-conditioning installation (1) for a motor vehicle comprising: - an air-conditioning loop (3) inside which circulates a refrigerant fluid (FR) comprising a compressor (7), a external heat exchanger (9), an evaporator (11), and, - a secondary loop (5) inside which circulates a coolant (FC), the air conditioning loop (3) and the secondary loop (5). ) being in interaction via a bi-fluid heat exchanger (19). The air conditioning loop (3) comprises at least - a first switching member (15) arranged between the compressor (7) and the external heat exchanger (9) - a second switching member (15) arranged between the exchanger external heat source (9) and the bi-fluid heat exchanger (19), and - a third switching member (15) arranged between the compressor (7) and the bi-fluid heat exchanger (19). The present invention also relates to a method of implementing such a heating, ventilation and / or air conditioning system (1).

Description

Heating, ventilation and / or air-conditioning installation for a motor vehicle and method for implementing such an installation. The invention is specific to the field of heating, ventilation and / or air conditioning of a motor vehicle, including an electric or hybrid motor vehicle. The invention also relates to a method of implementing such a heating, ventilation and / or thermal air conditioning system according to various modes of operation.

A motor vehicle, particularly an electric or hybrid motor vehicle whose propulsion is at least partially provided by an electric motor, is commonly equipped with a heating, ventilation and / or air conditioning system to modify the aerothermal parameters of a passenger compartment of the vehicle. by delivering a flow of conditioned air inside the passenger compartment.

The heating, ventilation and / or thermal air conditioning installation may comprise an air conditioning loop, inside which a refrigerant circulates, and a secondary loop, inside which circulates a heat transfer fluid.

A bi-fluid heat exchanger is integrated in the air conditioning loop and the secondary loop, so that the coolant and the heat transfer fluid can exchange heat reciprocally.

In the traditional way, the air conditioning loop comprises a compressor, capable of compressing the refrigerant, at least one expansion member, adapted to allow expansion of the cooling fluid, an external heat exchanger, adapted to allow a heat exchange between the refrigerant and a flow of ambient air, such as a flow of air outside the vehicle, and an indoor heat exchanger, adapted to allow a heat exchange between the refrigerant and an indoor air flow, adapted to be broadcast inside the cabin. In addition, the air conditioning loop may include at least one control device, adapted to allow an arrangement of the heating, ventilation and / or air conditioning according to various modes of operation. Furthermore, the air-conditioning loop may also include a refrigerant accumulator, adapted to prevent an intake of refrigerant fluid in the liquid state inside the compressor. The secondary loop comprises a second indoor heat exchanger, capable of exchanging heat with the coolant, advantageously provided for heating the interior air flow intended to be diffused inside the passenger compartment. However, the use of such a heating, ventilation and / or air conditioning system alternately according to a so-called "heating" mode of operation, in which the interior air stream is reheated prior to the diffusion of the latter into the room. The passenger compartment of the vehicle, and according to a mode of operation called "air conditioning", in which the interior air flow is cooled prior to the diffusion of it in the passenger compartment, may prove ineffective. In addition, such heating, ventilation and / or air conditioning systems may pose risks of icing of the external heat exchanger, for example when switching between two modes of operation, in particular, in the event of a temperature of the heat flow. relatively low outside air or when it is desired to extract heat from the outside air flow. In addition, such heating, ventilation and / or air conditioning systems are not suitable for diffusing the interior air flow without fogging the windshield and / or the windows of the vehicle, for example when switching between two modes of operation. operation of the heating, ventilation and / or air conditioning system. Moreover, certain known heating, ventilation and / or air-conditioning installations make it possible to ensure the cooling of electrical equipment of the vehicle, such as a battery, a motor or an electronic power unit. However, such heating, ventilation and / or air conditioning systems may require a large number of components to perform such a cooling function of electrical equipment.

An object of the present invention is to provide a heating, ventilation and / or air conditioning system suitable for equipping an electric or hybrid motor vehicle, offering various modes of operation, in particular a mode of operation called "air conditioning" and at least one mode of operation. operation called "heat pump" or "heating". In addition, such a heating, ventilation and / or air conditioning system is arranged to allow a so-called "defrost" operating mode, and to allow a simple way of operating a "cooling component" mode.

Another object of the present invention is to propose a method of implementing such a heating, ventilation and / or air conditioning installation in order to configure the heating, ventilation and / or air-conditioning system according to various operating modes so as to simple. For this purpose, the subject of the invention is a heating, ventilation and / or air-conditioning installation for a motor vehicle comprising: an air conditioning loop inside which circulates a refrigerant fluid comprising a compressor, an external heat exchanger, capable of ensuring a heat exchange with an outside air flow, an evaporator, adapted to ensure a heat exchange with a cabin air flow intended to be diffused in a cabin of the vehicle and advantageously connected to the compressor, and a secondary loop inside which a heat transfer fluid circulates, the air conditioning loop and the secondary loop being in interaction via a bi-fluid heat exchanger, capable of ensuring a heat exchange between the fluid refrigerant and heat transfer fluid.

More particularly, the air conditioning circuit comprises at least - a first switching member arranged between the compressor and the external heat exchanger, - a second switching member arranged between the external heat exchanger and the two-way heat exchanger. fluid and - a third switching member arranged between the compressor and the bi-fluid heat exchanger.

Advantageously, the external heat exchanger and / or the bi-fluid heat exchanger are configured to function as a condenser or as an evaporator. In addition, the air-conditioning loop comprises: a first expansion element, interposed between the external heat exchanger and the second switching member, and / or a second expansion element, arranged upstream of the evaporator, according to the refrigerant circulation direction, and / or - a third expansion member, arranged downstream of the evaporator, in the refrigerant circulation direction. Advantageously, the air conditioning circuit comprises at least one bypass device arranged in parallel with the first detent member and / or in parallel with the second detent member and / or in parallel with the third detent member. Preferably, such a bypass device comprises a nonreturn valve. Furthermore, the air conditioning loop comprises an accumulator arranged upstream of the compressor, according to the refrigerant circulation direction.

Alternatively or in addition, the secondary loop comprises an indoor heat exchanger, able to ensure a heat exchange with a cabin air flow. According to such an arrangement, the evaporator is arranged upstream of the indoor heat exchanger, according to the direction of flow of the cabin air flow capable of being diffused into the passenger compartment of the vehicle.

In addition, an additional heat exchanger is arranged downstream of the indoor heat exchanger. According to another alternative embodiment, the secondary loop comprises an auxiliary heat exchanger, adapted to ensure a heat exchange between the coolant and a component embedded in the vehicle. Preferably, the air-conditioning loop comprises a fourth switching element, arranged upstream of the evaporator, preferably between the second switching member and the second expansion member, in the direction of circulation of refrigerant fluid. According to another alternative or complementary embodiment, the secondary loop comprises a heat storage device. The present invention also relates to a method for implementing a heating, ventilation and / or air conditioning system according to the above detailed characteristics comprising at least one step of arranging the first switching member, the second switching member. and the third switching member so that, from the compressor, the refrigerant circulates successively - in the external heat exchanger and then in the evaporator, in particular according to an operating mode called "air conditioning", and / or - in the bi-fluid heat exchanger and then in the external heat exchanger, in particular in a first operating mode called "heat pump" or "heating", and / or - in the bi-fluid heat exchanger then in the evaporator, in particular in a second operating mode called "heat pump" or "heating", and / or - in the external heat exchanger and then in the heat exchanger bi-fluid, according to a mode of operation called "defrosting", and / or - in the external heat exchanger and, on the one hand, in the bi-fluid heat exchanger and, on the other hand, in the evaporator, in particular according to a mode of operation called "cooling of a component", - in the bi-fluid heat exchanger and then, on the one hand, in the external heat exchanger and, on the other hand, in the evaporator, in particular according to a mode of operation known as "heat pump with double expansion".

In addition, the method of implementation may also comprise: a step of deactivating the secondary loop, or a step of activating the secondary loop.

Furthermore, the step of arranging the first switching member, the second switching member and the third switching member is such that, independently or in combination, the coolant does not circulate: in the heat exchanger, bi-fluid heat, and / or - in the evaporator, and / or - in the external heat exchanger. In addition, the step of arranging the first switching member, the second switching member and the third switching member is such that, at the outlet of the evaporator and / or at the outlet of the bifluid heat exchanger and / or at the outlet of the external heat exchanger, the coolant flows to the compressor. Of course, the various features, variations and / or embodiments of the present invention may be associated with each other in various combinations to the extent that they are not incompatible or exclusive of each other.

The present invention will be better understood and other characteristics and advantages will become apparent on reading the following detailed description comprising embodiments given by way of illustration with reference to the appended figures, presented by way of non-limiting examples, which may be used to complete the understanding of the present invention and the explanation of its implementation and, where appropriate, contribute to its definition, in which: - Figure 1 is a schematic representation of a heating, ventilation and / or air conditioning of a motor vehicle according to the present invention, - Figure 2 is a schematic representation of the heating, ventilation and / or air conditioning system of Figure 1 according to a mode of operation called "air conditioning", - Figure 3 is a schematic representation of the heating, ventilation and / or air conditioning system of FIG. of operation known as "heat pump" or "heating", - Figure 4 is a schematic representation of the heating, ventilation and / or air conditioning system of Figure 1 according to a second mode of operation called "heat pump" or "heating", - Figure 5 is a schematic representation of the heating, ventilation and / or air conditioning system of Figure 1 according to a mode of operation called "defrosting", - Figure 6 is a schematic representation of the heating, ventilation and / or air conditioning system of FIG. 1 according to an operating mode called "cooling of a component", - FIG. 7 is a schematic representation of the heating, ventilation and / or air conditioning system of FIG. 1 according to a mode of operation known as "heat pump with double expansion", and - Figure 8 is a schematic representation of an alternative embodiment of a heating, ventilation and / or clima according to the present invention.

It should be noted that, in the figures, the structural and / or functional elements common to the various embodiments may have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties.

Figure 1 is a schematic representation of a heating, ventilation and / or air conditioning system 1 of a motor vehicle according to the present invention.

Such a heating, ventilation and / or air conditioning system 1 makes it possible to modify the aerothermal parameters of a passenger compartment of a vehicle by diffusing a cabin air flow FH, or interior air flow, at a defined temperature inside. of the cockpit. For this purpose, the heating, ventilation and / or air conditioning system 1 may comprise a blower (not shown) for circulating the interior airflow FH from at least one air intake mouth to at least one mouth air diffusion in the passenger compartment. In particular, it may be a defrosting / defogging mouth capable of diffusing the cabin airflow FH to the windshield and / or windows of the vehicle. According to the present invention, the heating, ventilation and / or air-conditioning system 1 comprises an air-conditioning loop 3, in which a refrigerant fluid FR circulates, and a secondary loop 5, in which circulates an heat-transfer fluid FC, such as a mixture of water and glycol. According to the present invention, the terms "downstream", "upstream", "in series" and "in parallel" describe the position of one component relative to another, according to the direction of circulation of the refrigerant fluid FR in the loop of air conditioning 3 or 30 depending on the flow direction of the heat transfer fluid FC in the secondary loop 5.

In addition, according to the present invention, the terms "open" and "closed" describe the state of a component allowing, respectively, to allow and / or block a passage of refrigerant FR or heat transfer fluid FC.

According to the exemplary embodiment presented, the air-conditioning loop 3 comprises a compressor 7, an external heat exchanger 9, capable of ensuring a heat exchange with an outside air flow FE, an evaporator 11, capable of ensuring a heat exchange with the cabin air flow FH, at least a first expansion member 131 adapted to ensure a relaxation of the refrigerant fluid FR. Preferably, the air conditioning loop 3 comprises the first expansion member 131 and a second expansion member 132, adapted to provide a relaxation of the refrigerant fluid FR. In addition, the air conditioning loop 3 comprises at least a first switching member 151 for configuring the heating, ventilation and / or air conditioning system 1 according to different modes of operation. Preferably, the air conditioning loop 3 comprises the first switching member 151, a second switching member 152 and a third switching member 153, for configuring the heating, ventilation and / or air conditioning system 1 according to different modes of operation. Advantageously, the air conditioning loop 3 also comprises a fourth switching member 17. The various operating modes of the heating, ventilation and / or air conditioning system are, by way of example: a mode of operation known as "air conditioning ", able to cool the flow of cabin air FH diffused in the passenger compartment, - a first mode of operation called" heat pump "or" heating ", able to heat the interior airflow FH diffused into the passenger compartment - A second mode of operation called "heat pump" or "heating", able to dehumidify and then heat the flow of cabin air FH distributed in the passenger compartment, - a mode of operation called "defrosting", able to ensure a defrosting of the external heat exchanger 9, - an operating mode called "cooling of a component", able to cool, on the one hand, the interior air flow FH diffused into the passenger compartment and, on the other hand, part, a component arranged in the vehicle, and - a mode of operation called "heat pump with double expansion". The different modes of operation will be described in more detail later.

The air conditioning loop 3 and the secondary loop 5 are interacting via a bi-fluid heat exchanger 19, adapted to ensure a heat exchange between the refrigerant fluid FR and the coolant FC. The secondary loop 5 comprises an inner heat exchanger 21, capable of providing a heat exchange with the cabin air flow FH diffused into the passenger compartment. In addition, the secondary loop 5 may comprise a pump, not shown, adapted to ensure the circulation of the heat transfer fluid FC in the secondary loop 5. In operation, the compressor 7 receives, as input, the refrigerant fluid FR in the state gaseous, low pressure and low temperature, as schematically illustrated by the acronym BP in the figures. The compressor 7 makes it possible to raise the pressure and the temperature of the refrigerating fluid FR, as schematically illustrated by the symbol HP in the figures. In addition, an accumulator 23 can be provided upstream of the compressor 7, making it possible to separate a gaseous phase and a liquid phase from the refrigerating fluid FR so as to avoid an intake of refrigerant fluid FR to the liquid state inside the compressor 7.

The external heat exchanger 9 is, for example, arranged at the front of the vehicle so as to be traversed by the outside air flow FE from the outside of the vehicle.

The outdoor heat exchanger 9 is able to function as a condenser or as an evaporator, depending on the operating mode of the heating, ventilation and / or air-conditioning system 1. As a condenser, the heat exchanger Outside heat 9 receives the refrigerant FR as a high temperature gas. The high temperature gas gives heat to the outside air flow FE, passing through the outdoor heat exchanger 9, which has the effect of heating the outside air flow FE. As an evaporator, the refrigerant FR evaporates in the outdoor heat exchanger 9. By evaporating, the refrigerant FR absorbs heat from the outside air flow FE, passing through the outdoor heat exchanger 9, which has the effect of cooling the outside air flow FE. According to the present invention, a first expansion member 131 is advantageously arranged in series with the external heat exchanger 9. More specifically, the first expansion member 131 is interposed between the external heat exchanger 9 and the second Furthermore, the second switching member 152 is connected to the bi-fluid heat exchanger 19. In particular, when the external heat exchanger 9 operates as an evaporator, the refrigerant FR is circulated in series in the first expansion member 131, so as to lower the pressure and the temperature of the refrigerant FR, then in the outdoor heat exchanger 9. In addition, there can be provided a bypass device 25 in parallel with the first expansion member 131, so as to form a bypass for deflecting the refrigerant fluid FR from the external heat exchanger 9 to the evaporator 11. Advantage Therefore, the bypass device 25 is able to allow or prohibit a circulation of the refrigerant fluid FR inside the first expansion member 131, to which it is assigned.

The bypass device 25 comprises, for example, a check valve allowing the circulation of the refrigerant fluid FR in one direction and prohibiting the circulation of the refrigerant fluid FR in the other direction.

In a variant, when the external heat exchanger 9 functions as a condenser, the refrigerant fluid FR flows in series in the external heat exchanger 9 and then in the first expansion member 131, so as to lower the pressure and the temperature FR refrigerant after condensation.

Alternatively or in addition, the bypass device 25 may comprise a two-way valve whose opening is controlled so that the refrigerant bypasses the first expansion member 131. The two-way valve can be arranged alone or in parallel check valve.

The refrigerating fluid FR evaporates in the evaporator 11. By evaporating, the refrigerating fluid FR absorbs the heat of the cabin air flow FH, able to be diffused into the passenger compartment, which has the effect of cooling the cabin airflow FH. According to the illustrated embodiment, a second expansion member 132 is arranged upstream of the evaporator 11. The expansion allows to lower the pressure and temperature of the refrigerant fluid FR. Advantageously, the second expansion member 132 is interposed between the second switching member 152 and the evaporator 11, in particular between the fourth switching member 17 and the evaporator 11.

The evaporator 11 is further connected to the compressor 7, optionally after passing through the accumulator 23. Thus, the refrigerant fluid FR at low pressure and low temperature, at the outlet of the evaporator 11, returns to the compressor 7 in order to start again. a thermodynamic cycle specific to the refrigerant fluid FR in the air conditioning loop 3.

Furthermore, the evaporator 11 is, according to the illustrated example, arranged upstream of the inner heat exchanger 21 of the secondary loop 5, according to the direction of flow of the interior airflow FH adapted to be diffused in the passenger compartment of the vehicle.

Such an arrangement is, in particular, of interest for dehumidifying the cabin air flow FH by cooling it by passing through the evaporator 11 before heating it by passing through the indoor heat exchanger 21. In addition, according to an alternative of embodiment not shown, it can provide a third expansion member arranged downstream of the evaporator 11 in the direction of flow of the refrigerant fluid FR. Thus, the refrigerating fluid FR at the outlet of the evaporator 11 undergoes a new expansion before returning to the compressor 7.

Of course, similarly to the arrangement of the first expansion member 131, it is possible to provide in parallel the second expansion member 132, possibly in parallel with the third expansion member, a bypass device comprising for example an anti-damper -return.

The air-conditioning loop 3 furthermore comprises a plurality of switching members, respectively the first switching member 151, the second switching member 152 and the third switching member 153, arranged so as to be able to configure the heating, ventilation and / or heating system. or air conditioning 1 between different modes of operation in a simple way. In particular, the first switching member 151, the second switching member 152 and the third switching member 153 are formed as three-way valves.

According to the present invention, the first switching member 151 is arranged between the compressor 7 and the external heat exchanger 9. The first switching member 151 comprises a first channel and a second channel for the circulation of the refrigerant fluid FR, the first channel and the second channel being distinct. The first channel of the first switching member 151 is such that the refrigerant fluid FR flows from the compressor 7 to the external heat exchanger 9. The second channel of the first switching member 151 is such that the refrigerant fluid FR flows from the External heat exchanger 9 to the compressor 7. The second switching member 152 is arranged between the outdoor heat exchanger 9 and the bi-fluid heat exchanger 19. More specifically, the second switching member 152 is For example, inserted between the first expansion member 131 and the bi-fluid heat exchanger 19. The second switching member 152 comprises a first channel and a second channel for the circulation of the refrigerant fluid FR, the first channel and the second channel. channel being distinct. The first channel of the second switching member 152 is such that the refrigerant fluid FR flows from the bi-fluid heat exchanger 19 to the outdoor heat exchanger 9. The refrigerant fluid FR can also circulate in the first channel for the first time. external heat exchanger 9 to the bi-fluid heat exchanger 19. The second channel of the second switching member 153 is such that the refrigerating fluid FR flows from the bi-fluid heat exchanger 19 to the evaporator 11. The third switching member 153 is arranged between the compressor 7 and the bi-fluid heat exchanger 19. The third switching member 153 also comprises a first channel and a second channel for the circulation of the refrigerant fluid FR, the first channel and the second channel being distinct. The first channel of the third switching member 153 is such that the refrigerant fluid FR flows from the compressor 7 to the bifluid heat exchanger 19. The second channel of the third switching member 153 is such that the refrigerant fluid FR flows from the exchanger bi-fluid heat 19 to the compressor 7, optionally after passing through the accumulator 23.

The first switching member 151, the second switching member 152 and the third switching member 153 make it possible to implement or bypass the various elements constituting the heating, ventilation and / or air conditioning system 1 according to the defined operating mode. .

In addition, the air conditioning loop 3 comprises the fourth switching member 17, in particular a two-way valve 17, arranged upstream of the evaporator 11. The fourth switching member 17 is configured to allow or prohibit, in whole or in part, the circulation of the refrigerant fluid FR in the evaporator 11 according to the mode of operation.

Furthermore, similarly to the external heat exchanger 9, the bi-fluid heat exchanger 19 can work as a condenser or as an evaporator, depending on the operating mode of the heating installation , ventilation and / or air conditioning 1.

When the bi-fluid heat exchanger 19 operates as a condenser, the refrigerant fluid FR flows in the bi-fluid heat exchanger 19 in the form of hot gas which gives heat to the coolant FC. In this configuration, the secondary loop 5 then functions as a heating system. When the bi-fluid heat exchanger 19 operates as an evaporator, the cooling fluid FR, while evaporating, absorbs the heat of the coolant FC, which has the effect of cooling the coolant FC. In this configuration, the secondary loop 5 then functions as a cooling system.

Furthermore, an additional heat exchanger 27 may be arranged downstream of the indoor heat exchanger 21, in the direction of flow of the cabin airflow FH adapted to be diffused in the passenger compartment of the vehicle. The additional heat exchanger 27 may in particular be an electric resistance heating radiator, in particular with a positive temperature coefficient. The additional heat exchanger 27 may, for example, be implemented to compensate for a cooling of the cabin airflow FH.

Furthermore, according to an alternative embodiment, the secondary loop 5 may comprise an auxiliary heat exchanger 29, between the coolant FC and a component embedded in the vehicle, including an electrical component of the vehicle. The auxiliary heat exchanger 29 is connected to the bi-fluid heat exchanger 19.

Figure 6 shows more particularly the auxiliary heat exchanger 29 between the heat transfer fluid FC and a battery of the vehicle. Other electrical components are conceivable such as an electric motor or an electronic power unit. As will be described in more detail later, the heating, ventilation and / or air conditioning system 1 can be used to cool such an electrical component in the operating mode called "cooling a component". The various modes of operation of the heating, ventilation and / or air-conditioning system 1 are now described. More precisely, FIGS. 2 to 8 are diagrammatic representations of the heating, ventilation and / or air-conditioning installation 1 according to different respective modes of operation.

As a result, in the figures, it will be considered, by convention, that the dotted lines are used to define a part of the air conditioning loop 3 in which does not circulate the refrigerant FR or part of the secondary loop 5 in which ne circulates the heat transfer fluid FC, and the solid lines are used to define a part of the air conditioning loop 3 in which circulates the refrigerant fluid FR or part of the secondary loop 5 in which circulates the heat transfer fluid FC.

Figure 2 is a schematic representation of the heating, ventilation and / or air conditioning system of Figure 1 in the operating mode called "air conditioning". The so-called "air-conditioning" operating mode makes it possible to condition the flow of cabin air FH capable of being diffused into the passenger compartment of the vehicle in order to cool it down. For this purpose, the refrigerating fluid FR, at the outlet of the compressor 7, is first condensed in the external heat exchanger 9, functioning as a condenser, then undergoes expansion, in the second expansion member 132, before to pass in the evaporator 11, through which the air flow FH thus cooled. In the so-called "air-conditioning" operating mode, the first switching member 151, the second switching member 152, the third switching member 153 and the fourth switching member 17 are arranged so that the cooling fluid FR flows from the compressor 7 to the external heat exchanger 9, operating as a condenser, then deflecting the refrigerant FR towards the evaporator 11 and preventing access to the bi-fluid heat exchanger 19. the air conditioning loop 3 is configured so that: - the first channel of the first switching member 151 is opened and, preferably, the second channel of the first switching member 151 is closed, and - the first channel of the second switching member 151 is closed, switching 152 and the second channel of the second switching member 152 is closed, - the first channel of the third switching member 153 is closed, and the second channel of the third me switch member 153, and - the fourth switching member 17 is opened In addition, the bypass device 25 is opened in parallel with the first expansion member 131. In the operating mode called "air conditioning", the second switching member 152 and the bypass device 25 are arranged to prevent access to the bi-fluid heat exchanger 19 and so as to divert the refrigerant fluid FR to the second expansion member 132 and then in the evaporator 11. In the external heat exchanger 9, operating as a condenser, the refrigerating fluid FR, in the gaseous state at high pressure and at high temperature, gives heat to the outside air flow FE. Then at the passage of the refrigerant FR in the second expansion member 132, the pressure and the temperature of the refrigerant FR are lowered. During the passage through the evaporator 11, the refrigerating fluid FR, while evaporating, absorbs the heat of the airflow FH passing through the evaporator 11. The flow of cabin air FH passing through the evaporator 11 is thus cooled. In the so-called "air conditioning" operating mode, the secondary loop 5 is deactivated so that the heat transfer fluid FC does not circulate between the indoor heat exchanger 21 and the bi-fluid heat exchanger 19.

Thus, the cabin air flow FH adapted to be diffused into the passenger compartment through the evaporator 11, then optionally the indoor heat exchanger 21 downstream of the evaporator 11, does not undergo additional heat exchange.

By reaching the passenger compartment of the vehicle, for example under the action of a blower not shown, the cooled cabin air flow FH reduces the air temperature of the passenger compartment.

The refrigerant FR, at the outlet of the evaporator 11, then returns to the compressor 7, to start a cycle again. The refrigerating fluid FR may, beforehand, undergo a new expansion, for example, when a third expansion element is arranged downstream of the evaporator 11.

In addition, the accumulator 23, possibly arranged upstream of the compressor 7, makes it possible to avoid the admission of refrigerant fluid FR in the liquid state into the compressor 7. The compressor 7 thus receives, on admission, the refrigerant fluid FR in the gaseous state under low pressure and low temperature.

Figure 3 is a schematic representation of the heating, ventilation and / or air conditioning system of Figure 1 according to the first mode of operation called "heat pump" or "heating". In the first mode of operation known as "heat pump" or "heating", the refrigerating fluid FR at the outlet of the compressor 7 exchanges heat with the coolant FC in the bi-fluid heat exchanger 19, before undergoing a expansion, in the first expansion member 131, and pass into the outdoor heat exchanger 9, operating as an evaporator.

In the first mode of operation known as "heat pump", the first switching member 151, the second switching member 152, the third switching member 153 and the fourth switching member 17 are arranged so that the refrigerating fluid FR circulates. from the compressor 7 to the bi-fluid heat exchanger 19, then to the outdoor heat exchanger 9, operating as an evaporator, passing via the first expansion member 131, then to the compressor 7, passing possibly by the accumulator 23. In particular, the air conditioning loop 3 is configured so that: - the second channel of the first switching member 151 is opened, and, preferably, the first channel of the first switching member 151 is closed, the first channel of the second switching member 152 is opened, and, preferably, the second channel of the second switching member 152 is closed; the first channel of the third opening is opened; me switch member 153, and, preferably, the second channel of the third switching member 153 is closed, and - the fourth switching member 17 is closed. The bi-fluid heat exchanger 19, operating as a condenser, receives Thus, at the inlet, on the one hand, the refrigerating fluid FR in the form of hot gas, and, on the other hand, the coolant FC. The coolant FR transfers heat to the heat transfer fluid FC which circulates in the indoor heat exchanger 21. In the first mode of operation known as "heat pump", the secondary loop 5 is activated so that the coolant FC circulates in the secondary loop 5 between the indoor heat exchanger 21 and the bi-fluid heat exchanger 19, so as to allow a heat exchange between the refrigerant FR and the coolant FC. Thus, the secondary loop 5 draws heat from the air conditioning loop 3, via the bi-fluid heat exchanger 19, and then transfers the heat drawn to the interior air flow FH via of the indoor heat exchanger 21. The cabin air flow FH through the indoor heat exchanger 21, is heated and can warm the vehicle interior. After the exchange of heat with the coolant FC, the coolant FR undergoes a relaxation, passing through the first expansion member 131, lowering the pressure and the temperature, before evaporating in the external heat exchanger 9, operating as an evaporator. The refrigerant fluid FR, in the gaseous state and at low pressure and low temperature, then returns to the compressor 7 to start a cycle again.

Moreover, the first mode of operation known as "heat pump" is a heating mode in which the cabin air flow FH is heated by the indoor heat exchanger 21 of the secondary loop 5. We therefore speak of indirect heating, because the heating of the cabin air flow FH is carried out via the coolant FC and not directly by the refrigerant FR. When the heat transfer fluid FC consists mainly of water, it is called heating mode on "water". In addition, for the first mode of operation known as "heat pump", the cabin air flow FH is, advantageously, a fresh air flow coming from outside the vehicle, as opposed to the use of a stream of recycled air from the passenger compartment. Figure 4 is a schematic representation of the heating, ventilation and / or air conditioning system of Figure 1 according to the second mode of operation called "heat pump" or "heating". The second mode of operation known as "heat pump" differs from the first mode of operation known as "heat pump" previously described by the fact that the cabin airflow FH to the passenger compartment is dehumidified before crossing the indoor heat exchanger 21 for heating the cabin.

To do this, the refrigerating fluid FR at the outlet of the compressor 7 circulates in series in the bi-fluid heat exchanger 19 and then in the evaporator 11. In the second operating mode, called "heat pump", the first member 151, the second switching member 152, the third switching member 153 and the fourth switching member 17 are arranged so that the refrigerant fluid FR flows from the compressor 7 to the bi-fluid heat exchanger 19, then to the evaporator 11 by undergoing a prior expansion, through the second expansion member 132, and then returns to the compressor 7. In particular, the air conditioning loop 3 is configured so that: - the first channel of the first is closed switching member 151 and closing the second channel of the first switching member 151, - opening the second channel of the second switching member 152 and, preferably, closing the first can 1a of the second switching member 152, opening the first channel of the third switching member 153, and preferably closing the second channel of the third switching member 153, and opening the fourth switching member 17. in the second so-called "heat pump" operating mode, the secondary loop 5 is activated so that the coolant FC circulates in the secondary loop 5 between the indoor heat exchanger 21 and the two-way heat exchanger. fluid 19. Thus, the refrigerant fluid FR, at high pressure and at high temperature, at the outlet of the compressor 7 enters the bi-fluid heat exchanger 19, operating as a condenser, and gives up heat to the coolant FC, for heating the cabin airflow FH adapted to be diffused in the cabin at the crossing of the indoor heat exchanger 21.

As a result, the refrigerating fluid FR undergoes expansion through the second expansion member 132 which lowers the pressure and the refrigerant temperature FR, before passing into the evaporator 11. The refrigerant FR evaporates while absorbing the heat the cabin airflow FH that passes through it. The refrigerant fluid FR can then return to the compressor 7 to start a cycle again. The cabin air flow FH, passing through the evaporator 11, is thus cooled and dehumidified before passing through the indoor heat exchanger 21, to be heated prior to being diffused into the passenger compartment. In addition, for the second mode of operation known as "heat pump" described, advantageously, the interior air flow FH is a recycled air stream, that is to say the air flow of the passenger compartment circulating again in the heating, ventilation and / or air-conditioning installation 1. FIG. 5 is a schematic representation of the heating, ventilation and / or air-conditioning installation of FIG. 1 according to the operating mode referred to as "defrosting" ". For this purpose, the refrigerating fluid FR, at the outlet of the compressor 7, passes through the external heat exchanger 9, functioning as a condenser, before passing into the bi-fluid heat exchanger 19, operating as evaporator. In the so-called "defrost" operating mode, the first switching member 151, the second switching member 152, the third switching member 153 and the fourth switching member 17 are arranged so that the cooling fluid FR flows from the compressor 7 to the outdoor heat exchanger 9, operating as a condenser, then to the bi-fluid heat exchanger 19, operating as an evaporator, while access to the evaporator 11 is prohibited, and finally returns to the compressor 7. In particular, the air conditioning loop 3 is configured so that: - the first channel of the first switching member 151 is opened and, preferably, the second channel of the first switching member 151 is closed; opening the first channel of the second switching member 152, and, preferably, closing the second channel of the second switching member 152, - opening the second channel of the third o switching member 153 and, preferably, the first channel of the third switching member 153 is closed, and - the fourth switching member 17 is closed.

In the so-called "defrosting" operating mode, the secondary loop 5 is activated so that the coolant FC circulates in the secondary loop 5 between the indoor heat exchanger 21 and the bi-fluid heat exchanger 19, to ensure a heat exchange between the heat transfer fluid FC and the refrigerant fluid FR in the bi-fluid heat exchanger 19, operating as an evaporator, so as to cool the coolant FC. Thus, by circulating in the external heat exchanger 9, functioning as a condenser, the refrigerant fluid FR, in the gaseous state at high pressure and at high temperature, gives heat to the external air flow FE. Then at the passage of the refrigerant fluid FR in the first expansion member 131, the pressure and the temperature of the refrigerant fluid FR are lowered before circulating in the bi-fluid heat exchanger 19, operating as an evaporator.

During the passage of the refrigerant fluid FR in the bi-fluid heat exchanger 19, operating as an evaporator, the cooling fluid FR evaporating absorbs the heat of the coolant FC. Thus, the calories are drawn from the heat transfer fluid FC, comprising for example a mixture of water and glycol.

The heat transfer fluid FC thus cooled returns to the indoor heat exchanger 21. The interior airflow FH capable of being diffused into the passenger compartment passing through the indoor heat exchanger 21 is thus cooled. In the operating mode known as "defrosting", it is advantageous to use the additional heat exchanger 27, for example an electric resistance heating radiator, in particular with a positive temperature coefficient, arranged downstream of the indoor heat exchanger. 21, so as to compensate for the discomfort generated by the cooling of the heat transfer fluid FC and / or the passage of the evaporator 11 and / or the indoor heat exchanger 21 and to heat the cabin air flow FH fit to be broadcast in the cockpit. Furthermore, according to an alternative embodiment not shown, it is possible to have in the secondary loop 5, an auxiliary heat exchanger 29 to ensure a heat exchange between the heat transfer fluid FC and a vehicle component, such as a battery for example. The auxiliary heat exchanger 29 is, according to this alternative, connected to the bi-fluid heat exchanger 19. Preferably, but not exclusively, the indoor heat exchanger 21 is no longer biased.

Thus, the heat transfer fluid FC circulating between the auxiliary heat exchanger 29 and the bi-fluid heat exchanger 19 is cooled by heat exchange with the refrigerant fluid FR in the bi-fluid heat exchanger 19. The heat transfer fluid FC cooled allows to cool the vehicle component.

In such a configuration, the so-called "defrosting" operating mode is also an operating mode called "cooling a component".

In addition, for the operating mode called "defrosting", the cabin airflow FH is advantageously a recycled air stream coming from the passenger compartment, as opposed to the use of an air flow. charges from outside the vehicle.

Figure 6 is a schematic representation of the heating, ventilation and / or air conditioning system of Figure 1 according to the operating mode called "cooling a component". Preferably, the operating mode called "cooling a component" is done without using a conventional conditioning function, for example air conditioning. As detailed above, the component may for example be a battery or any other component of the vehicle requiring to be cooled.

In the operating mode known as "cooling a component", the air conditioning loop 3 is similarly configured to the so-called "air conditioning" operating mode so that the refrigerant FR, at the outlet of the compressor 7, is firstly condensed in the outdoor heat exchanger 9, then undergone before passing into the evaporator 11.

However, in the so-called "cooling of a component" operating mode, at the outlet of the external heat exchanger 9, the refrigerant fluid FR also circulates towards the bi-fluid heat exchanger 19, operating as evaporator, for a heat exchange between the refrigerant fluid FR and the coolant FC, so as to cool the coolant FC and therefore the vehicle component, including the battery. Advantageously, in the operating mode called "cooling of a component", the indoor heat exchanger 21 is not stressed. Nevertheless, it is conceivable that the indoor heat exchanger 21 is arranged in parallel or in series with the auxiliary heat exchanger 29, able to cool the vehicle component.

In the operating mode called "cooling of a component", the first switching member 151, the second switching member 152, the third switching member 153 and the fourth switching member 17 are arranged so that the cooling fluid FR flows from the compressor 7 to the external heat exchanger 9, operating as a condenser, then to the first expansion member 131, then to the bi-fluid heat exchanger 19, and to the second expansion member 132, then to the evaporator 11, and finally back to the compressor 7.

In particular, the air conditioning loop 3 is configured so that: - the first channel of the first switching member 151 is opened and, preferably, the second channel of the first switching member 151 is closed, - the first channel of the second channel is opened; switching member 152, and, preferably, the first channel of the second switching member 152 is closed, - opening the second channel of the third switching member 153 and, preferably, closing the first channel of the third switching member 153, and the fourth switching member 17 is opened. In addition, the bypass device 25 is opened in parallel with the first expansion member 131.

In the operating mode called "cooling of a component", the secondary loop 5 is activated so that the coolant FC circulates in the secondary loop 5 between the auxiliary heat exchanger 29 and the bi-fluid heat exchanger 19, so that a heat exchange between the heat transfer fluid FC and the refrigerant FR occurs in the bi-fluid heat exchanger 19, operating as an evaporator, so as to cool the coolant FC.

Thus, the refrigerant fluid FR, at high pressure and at high temperature, at the outlet of the compressor 7 enters the external heat exchanger 9, functioning as a condenser, so that the refrigerating fluid FR transfers heat to the flow outside air FE. Then, the refrigerating fluid FR, at the outlet of the external heat exchanger 9, undergoes a relaxation, through the first expansion member 131, which lowers the pressure and the temperature of the refrigerating fluid FR before passing into the exchanger bi-fluid heat 19, operating as an evaporator, so that the refrigerant FR absorbs the heat of the coolant FC. The cooled FC heat transfer fluid circulates in the auxiliary heat exchanger 29 so as to cool the component of the vehicle, the battery for example. In addition, the refrigerating fluid FR at the outlet of the external heat exchanger 9 also undergoes expansion, through the second expansion member 132, before passing into the evaporator 11, where the cooling fluid FR evaporates. absorbs the heat of the air flow FH through the evaporator 11. The flow of cabin air FH able to be diffused into the passenger compartment passing through the evaporator 11 is thus cooled. Then, the refrigerant fluid FR, on the one hand, at the outlet of the bi-fluid heat exchanger 19, and, on the other hand, at the outlet of the evaporator 11, can return to the compressor 7 to restart a cycle . FIG. 7 is a diagrammatic representation of the heating, ventilation and / or air conditioning system of FIG. 1 according to the so-called "double-expansion heat pump" operating mode. In the so-called "double-expansion heat pump" operating mode, the first switching member 151, the second switching member 152, the third switching member 153 and the fourth switching member 17 are arranged so that the fluid FR refrigerant flows from the compressor 7 to the bi-fluid heat exchanger 19, then to the external heat exchanger 9 passing through the first expansion member 131, the outdoor heat exchanger 9 functioning as evaporator, and to the evaporator 11 passing through the second expansion member 132 and finally to the compressor 7. In particular, the air conditioning loop 3 is configured so that: - the second channel of the first switching member is opened 151 and, preferably, the first channel of the first switching member 151 is closed, the first channel of the second switching member 152 is opened and, preferably, the opening is closed. second channel of the second switching member 152, the first channel of the third switching member 153 is opened, and, preferably, the second third switching channel 153 is closed, and the fourth switching member 17 is opened.

In addition, the bypass device 25 is opened in parallel with the first expansion element 131. In the so-called "double-expansion heat pump" operating mode, the secondary loop 5 is activated so that the heat transfer fluid FC circulates in the secondary loop 5 between the indoor heat exchanger 21 and the bi-fluid heat exchanger 19, operating as a condenser, so as to allow a heat exchange between the refrigerant FR and the heat transfer fluid FC.

Such an arrangement therefore makes it possible to implement two detents in series. The external heat exchanger 9, downstream of the first expansion member 131, and the evaporator 11, downstream of the second expansion member 132, therefore work at different pressure levels. Thus, the refrigerant fluid FR, at high pressure and at high temperature from the compressor 7, yields, in the bi-fluid heat exchanger 19, heat to the coolant FC, for heating the air flow cabin FH adapted to be diffused in the passenger compartment through the indoor heat exchanger 21. As a result, the refrigerant FR then undergoes a first expansion through the first expansion member 131 which lowers the temperature and the pressure of the fluid FR refrigerant, then, on the one hand, the refrigerant fluid FR enters the external heat exchanger 9, in order to undergo evaporation, and, secondly, the refrigerant undergoes a second expansion through the second organ of detent 132 which further decreases the pressure and the temperature of the refrigerant FR, before passing through the evaporator 11. The refrigerant FR, leaving the evaporator 11, can then return to the 7 to start a cycle again. The flow of cabin air FH through the evaporator 11 is cooled and dehumidified before passing through the indoor heat exchanger 21, to be heated, before being diffused into the passenger compartment. Figure 8 is a schematic representation of an alternative embodiment of the heating, ventilation and / or air conditioning system 1 according to the present invention. The alternative embodiment of the heating, ventilation and / or air conditioning system 1 of FIG. 8 differs from the various operating modes described above in that the secondary loop 5 comprises a heat storage device 30 advantageously disposed between the bi-fluid heat exchanger 19 and the indoor heat exchanger 21.

Preferably, the heat storage device 30 allows cold storage to be restored later or to serve as a thermal lever for the operation of the air conditioning loop 3. Alternatively, the heat storage device 30 allows storage of hot .

It is therefore understood that the arrangement and the control, simultaneous and / or alternative, of the first switching member 151, the second switching member 152, the third switching member 153 and the fourth switching member 17 makes it easy to change the mode. operating the air conditioning loop 3, using fewer components than in known arrangements of the state of the art. Throughout the description of the present invention in connection with Figures 1 to 8, the first detent 131, the bypass device 25 and / or the second switching member 152 have been described as components of the loop 3 separate air conditioning. However, alternatively, the first expansion member 131, the bypass device 25 and / or the second switching member 152 may be combined in a single detent / bypass member to form an integrated system.

Similarly, the second expansion member 132 and the fourth switching member 17 have been described as components of the air conditioning loop 3 separate. However, alternatively, the second expansion member 132 and the fourth switching member 17 may be combined in a single expansion / switching member to form an integrated system. Of course, the invention is not limited to the embodiments described above and provided solely by way of example. It encompasses various modifications, alternative forms and other variants that may be envisaged by a person skilled in the art within the context of the present invention and in particular any combination of the different modes of operation described above,

Claims (29)

REVENDICATIONS1. Heating, ventilation and / or air-conditioning installation (1) for a motor vehicle comprising: - an air conditioning loop (3) inside which a refrigerant (FR) circulates comprising a compressor (7), an external heat exchanger ( 9), adapted to ensure a heat exchange with an outside air flow (FE), an evaporator (11), adapted to ensure a heat exchange with a cabin air flow (FH) intended to be broadcast in a cabin of the vehicle, and, - a secondary loop (5) inside which circulates a coolant (FC), the air conditioning loop (3) and the secondary loop (5) interacting through a bi-fluid heat exchanger (19), adapted to ensure a heat exchange between the refrigerant fluid (FR) and the coolant (FC), characterized in that the air conditioning loop (3) comprises at least - a first switching member (151) arranged between the compressor (7) and the external heat exchanger (9), - a second switching member (152) arranged between the external heat exchanger (9) and the bi-fluid heat exchanger (19), and - a third switching (153) arranged between the compressor (7) and the bi-fluid heat exchanger (19). Heating, ventilation and / or air conditioning system (1) according to claim 1, in which the outer heat exchanger (9) and / or the bi-fluid heat exchanger (19) are configured to operate in accordance with the present invention. as a condenser or as an evaporator. Heating, ventilation and / or air conditioning system (1) according to any one of the preceding claims, wherein the evaporator (11) is connected to the compressor (7). 4. Heating, ventilation and / or air conditioning system (1) according to any one of the preceding claims, wherein the air conditioning loop (3) comprises an expansion member, said first expansion member (134 interposed between the exchanger external heat source (9) and the second switching member (152). 5. Heating, ventilation and / or air conditioning system (1) according to any one of the preceding claims, wherein the air conditioning loop (3) comprises an expansion member, said second expansion member (132), arranged upstream. of the evaporator (11). 6. Heating, ventilation and / or air conditioning system (1) according to any preceding claim, wherein the air conditioning loop (3) comprises an expansion member, said third expansion member, arranged downstream of the evaporator (11). Heating, ventilation and / or air conditioning system (1) according to any one of claims 4 to 6, wherein the air conditioning circuit comprises at least one bypass device (25) arranged in parallel with the expansion device. . Heating, ventilation and / or air conditioning system (1) according to claim 7, wherein the bypass device (25) comprises a non-return valve. 9. Heating, ventilation and / or air conditioning system (1) according to any one of the preceding claims, wherein the air conditioning loop (3) comprises an accumulator (23) arranged upstream of the compressor (7). Heating, ventilation and / or air-conditioning installation (1) according to any one of the preceding claims, in which the secondary loop (5) comprises an internal heat exchanger (21), able to ensure a heat exchange with the interior airflow (FH). 11. Heating, ventilation and / or air conditioning system (1) according to claim 10, wherein the evaporator (11) is arranged upstream of the indoor heat exchanger (21). Heating, ventilation and / or air conditioning system (1) according to claim 10 or 11, wherein an additional heat exchanger (27) is arranged downstream of the indoor heat exchanger (21). Heating, ventilation and / or air conditioning system (1) according to any one of the preceding claims, in which the secondary loop (5) comprises an auxiliary heat exchanger (29) capable of ensuring a heat exchange between the coolant (FC) and a component embedded in the vehicle. Heating, ventilation and / or air conditioning system (1) according to one of the preceding claims, in which the air-conditioning loop (3) comprises a fourth switching element (17) arranged upstream of the evaporator ( 11). 15. Heating, ventilation and / or air conditioning system (1) according to any one of the preceding claims, wherein the secondary loop (5) comprises a heat storage device (30). 16. A method of implementing a heating, ventilation and / or air conditioning system (1) according to any one of claims 1 to 15, characterized in that it comprises at least one step of arranging the first member switching device (154) of the second switching member (152) and the third switching member (153) so that, from the compressor (7), the cooling fluid (FR) flows successively in the external heat exchanger (9). ) and then in the evaporator (11). 17. A method of implementing a heating, ventilation and / or air conditioning system (1) according to any one of claims 1 to 15, characterized in that it comprises at least one stage of arrangement of the first member. switching device (154) of the second switching element (152) and the third switching element (153) so that, from the compressor (7), the cooling fluid (FR) flows successively in the bi-fluid heat exchanger (19) then in the outdoor heat exchanger (9). 18. A method of implementing a heating, ventilation and / or air conditioning system (1) according to any one of claims 1 to 15, characterized in that it comprises at least one step of arranging the first member switching device (154) of the second switching element (152) and the third switching element (153) so that, from the compressor (7), the cooling fluid (FR) flows successively in the bi-fluid heat exchanger (19) then in the evaporator (11). 19. A method of implementing a heating, ventilation and / or air conditioning system (1) according to any one of claims 1 to 15, characterized in that it comprises at least one step of arranging the first member switching device (154) of the second switching member (152) and the third switching member (153) so that, from the compressor (7), the cooling fluid (FR) flows successively in the external heat exchanger (9). ) and then in the bifluid heat exchanger (19). 20. A method of implementing a heating, ventilation and / or air conditioning system (1) according to any one of claims 1 to 15, characterized in that it comprises at least one stage of arrangement of the first member. switching device (154) of the second switching member (152) and the third switching member (153) so that, from the compressor (7), the cooling fluid (FR) flows successively in the external heat exchanger (9). and then, on the one hand, in the bi-fluid heat exchanger (19) and, on the other hand, in the evaporator (11). 21. A method of implementing a heating, ventilation and / or air conditioning system (1) according to any one of claims 1 to 15, characterized in that it comprises at least one stage of arrangement of the first member. switching device (154) of the second switching element (152) and the third switching element (153) so that, from the compressor (7), the cooling fluid (FR) flows successively in the bi-fluid heat exchanger (19) then, on the one hand, in the external heat exchanger (9) and on the other hand, in the evaporator (11). 22. Method of implementation according to any one of claims 16 to 21, characterized in that it comprises a step of deactivating the secondary loop (5). 23. Method of implementation according to any one of claims 16 to 21, characterized in that it comprises a step of activating the secondary loop (5). 24. The method of implementation according to claim 16, wherein the step of arranging the first switching member (151), the second switching member (152) and the third switching member (153) is such that the refrigerant (FR) does not circulate in the bi-fluid heat exchanger (19). 25. The method of implementation according to claim 17 or 19, wherein the step of arranging the first switching member (151), the second switching member (152) and the third switching member (153) is such that the refrigerant (FR) does not circulate in the evaporator (11). 26. The method of implementation according to claim 18, wherein the step of arranging the first switching member (151), the second switching member (152) and the third switching member (153) is such that the refrigerant (FR) does not circulate in the outdoor heat exchanger (9). 27. The method of implementation according to any one of claims 16, 18, 20 and 21, wherein the step of arranging the first switching member (151), the second switching member (152) and the third switching member (153) is such that, at the outlet of the evaporator (11), the refrigerant (FR) flows to the compressor (7). 28. The method of implementation according to claim 19 or 20, wherein the step of arranging the first switching member (151), the second switching member (152) and the third switching member (153) is such that at the outlet of the bi-fluid heat exchanger (19), the refrigerant (FR) flows to the compressor (7). 29. The method of implementation according to claim 17 or 21, wherein the step of arranging the first switching member (151), the second switching member (152) and the third switching member (153) is such that at the outlet of the external heat exchanger (9), the refrigerant (FR) flows towards the compressor (7).