FR3092162A1 - Motor vehicle air conditioning circuit and associated management method - Google Patents

Abstract

The present invention relates to an invertible air conditioning circuit (1) comprising: a main loop (A) comprising a compressor (3), a water condenser (5) connected jointly to an auxiliary circuit, a first expansion device (7) , an external evapo-condenser (9), a second expansion device (15), and an evaporator (17), a first bypass branch (B) comprising an internal condenser (13), said first bypass branch (B) connecting a first junction point (31) arranged downstream of the water condenser (5) to a second junction point (32) arranged upstream of the second expansion device (15), a second bypass branch (C) connecting a third junction point (33) arranged downstream of the external evapo-condenser (9) to a fourth junction point (34) arranged downstream of the evaporator (17), a third bypass branch (D) connecting a fifth junction point (35) disposed on the first branch branch (B) downstream of the conde internal nseur (13) at a sixth junction point (36) disposed downstream of the first junction point (31), a second expansion device (21) disposed on the first branch branch (B) downstream of the fifth point of junction (35). Abstract figure: [Fig. 1]

Description

Motor vehicle air conditioning circuit and associated management method

The invention relates to the field of motor vehicles and more particularly to a motor vehicle air conditioning circuit and its management method.

Current motor vehicles increasingly include an air conditioning circuit. Generally, in a "conventional" air conditioning circuit, a refrigerant fluid passes successively through a compressor, a first heat exchanger, called a condenser, placed in contact with an air flow outside the motor vehicle to release heat, a device expansion and a second heat exchanger, called evaporator, placed in contact with a flow of air inside the motor vehicle to cool it.

There are also more complex air conditioning circuit architectures which make it possible to obtain a reversible air conditioning circuit, i.e. it can use a heat pump operating mode in which it is able to absorb energy. calorific in the outside air at the level of the first heat exchanger, then called evapo-condenser, and restore it in the passenger compartment in particular by means of a third dedicated heat exchanger.

This is possible in particular by using a dedicated internal condenser placed in the internal air flow and making it possible to heat said internal air flow.

The air conditioning circuit thus comprises a particular architecture making it possible to choose in which heat exchanger the refrigerant fluid passes in order to define its mode of operation.

The air conditioning circuit can also be connected to an auxiliary circuit in which a heat transfer fluid circulates. This additional circuit can for example allow the thermal management of batteries and/or electric motors, in particular in the context of a hybrid or electric motor vehicle. The air conditioning circuit can thus be used, for example, to heat the heat transfer fluid via a dedicated two-fluid heat exchanger called a water condenser or to cool the heat transfer fluid via another two-fluid heat exchanger also called a cooler.

However, this kind of architectures are not always satisfactory because they do not allow operation according to all the operating modes requested by the manufacturers.

One of the aims of the present invention is therefore to at least partially remedy the drawbacks of the prior art and to propose an architecture allowing a multitude of operating modes in order to meet the requirements of manufacturers and the needs of users.

• une boucle principale comportant dans le sens de circulation du fluide réfrigérant, un compresseur, un condenseur d’eau relié conjointement à un circuit annexe dans lequel circule un fluide caloporteur, un premier dispositif de détente, un évapo-condenseur externe destiné à être traversé par un flux d’air externe, un deuxième dispositif de détente, et un évaporateur destiné à être traversé par un flux d’air interne,
• une première branche de dérivation comportant un condenseur interne destiné à être traversé par un flux d’air interne, ladite première branche de dérivation reliant un premier point de jonction disposé en aval du condenseur d’eau, entre ledit condenseur et le premier dispositif de détente, à un deuxième point de jonction disposé en amont du deuxième dispositif de détente, entre l’évapo-condenseur externe et ledit deuxième dispositif de détente,
• une deuxième branche de dérivation reliant un troisième point de jonction disposé en aval de l’évapo-condenseur externe, entre ledit évapo-condenseur externe et le deuxième point de jonction, à un quatrième point de jonction disposé en aval de l’évaporateur, entre ledit évaporateur et le compresseur,
• une troisième branche de dérivation reliant un cinquième point de jonction disposé sur la première branche de dérivation en aval du condenseur interne à un sixième point de jonction disposé en aval du premier point de jonction, entre ledit premier point de jonction et le premier dispositif de détente, et
• un deuxième dispositif de détente disposé sur la première branche de dérivation en aval du cinquième point de jonction entre ledit cinquième point de jonction et le deuxième point de jonction.

The present invention relates to a reversible air conditioning circuit in which a refrigerant fluid circulates and comprising:

• a main loop comprising, in the direction of circulation of the refrigerant fluid, a compressor, a water condenser jointly connected to an auxiliary circuit in which a heat transfer fluid circulates, a first expansion device, an external evapo-condenser intended to be crossed by an external air flow, a second expansion device, and an evaporator intended to be crossed by an internal air flow,
• a first bypass branch comprising an internal condenser intended to be crossed by an internal air flow, said first bypass branch connecting a first junction point arranged downstream of the water condenser, between said condenser and the first expansion device , at a second junction point arranged upstream of the second expansion device, between the external evapo-condenser and said second expansion device,
• a second bypass branch connecting a third junction point disposed downstream of the external evapo-condenser, between said external evapo-condenser and the second junction point, to a fourth junction point disposed downstream of the evaporator, between said evaporator and the compressor,
• a third bypass branch connecting a fifth junction point disposed on the first bypass branch downstream of the internal condenser to a sixth junction point disposed downstream of the first junction point, between said first junction point and the first expansion device , and
• a second expansion device disposed on the first bypass branch downstream of the fifth junction point between said fifth junction point and the second junction point.

According to one aspect of the invention, the main loop comprises an internal heat exchanger configured to allow heat exchanges between the refrigerant at different pressures, said internal heat exchanger being arranged on the one hand between the third and the second junction point and on the other hand between the fourth junction point and the compressor.

According to another aspect of the invention, the reversible air conditioning circuit is configured to operate according to a first heat pump mode in which the refrigerant fluid circulates successively in the compressor, the water condenser, the first bypass branch at the level of which the refrigerant transfers heat energy to the internal air flow via the internal condenser, the refrigerant then passes through the third bypass branch, the first expansion device at which the refrigerant undergoes a loss of pressure, the external evapo-condenser at the level of which the refrigerant fluid absorbs calorific energy from the external air flow, the refrigerant fluid then passes through the second bypass branch before joining the compressor.

According to another aspect of the invention, the reversible air conditioning circuit is configured to operate according to a second heat pump mode in which the refrigerant fluid circulates successively in the compressor, the water condenser at the level of which the refrigerant fluid yields calorific energy to the heat transfer fluid of the auxiliary circuit, the first expansion device at the level of which the refrigerant fluid undergoes a loss of pressure, the external evapo-condenser at the level of which the refrigerant fluid absorbs heat energy from the air flow external, the refrigerant then passes through the second bypass branch before reaching the compressor.

• une première partie du fluide réfrigérant passe par la troisième branche de dérivation, le premier dispositif de détente au niveau duquel le fluide réfrigérant subit une perte de pression, l’évapo-condenseur externe au niveau duquel il absorbe de l’énergie calorifique du flux d’air externe, la deuxième branche de dérivation, et
• une deuxième partie du fluide réfrigérant passe par le troisième dispositif de détente au niveau duquel le fluide réfrigérant subit une première perte de pression et par le deuxième dispositif de détente au niveau duquel le fluide réfrigérant subit une deuxième perte de pression, le fluide réfrigérant passe ensuite par l’évaporateur au niveau duquel le fluide réfrigérant absorbe de l’énergie calorifique du flux d’air interne,

According to another aspect of the invention, the reversible air conditioning circuit is configured to operate according to a dehumidification mode in which the refrigerant fluid circulates successively in the compressor, the water condenser, the first bypass branch at which the refrigerant yields heat energy to the internal airflow via the internal condenser, the refrigerant then splits at the fifth junction point:

• a first part of the refrigerant fluid passes through the third bypass branch, the first expansion device at the level of which the refrigerant fluid undergoes a loss of pressure, the external evapo-condenser at the level of which it absorbs calorific energy from the flow of external air, the second bypass branch, and
• a second part of the refrigerant passes through the third expansion device at which the refrigerant undergoes a first pressure loss and through the second expansion device at which the refrigerant undergoes a second pressure loss, the refrigerant then passes by the evaporator at the level of which the refrigerant fluid absorbs heat energy from the internal air flow,

the two parts of the refrigerant fluid joining at the fourth junction point before returning to the compressor.

According to another aspect of the invention, the reversible air conditioning circuit further comprises a fourth bypass branch comprising, in the direction of circulation of the refrigerant fluid, a fourth expansion device and a cooler connected jointly to a circuit of a heat transfer fluid, said fourth branch branch connecting a seventh junction point disposed downstream of the second junction point, between said second junction point and the second expansion device to an eighth junction point disposed downstream of the evaporator, between said evaporator and the fourth junction point.

• en passant par le deuxième dispositif de détente, le fluide réfrigérant subit une deuxième perte de pression et l’évaporateur au niveau duquel le fluide réfrigérant absorbe de l’énergie calorifique du flux d’air interne, et
• en passant par le quatrième dispositif de détente, le fluide réfrigérant subit une deuxième perte de pression et le refroidisseur au niveau duquel le fluide réfrigérant absorbe de l’énergie calorifique du fluide caloporteur du circuit annexe,

According to another aspect of the invention, the reversible air conditioning circuit is configured to operate according to a first defrosting mode in which the refrigerant fluid circulates successively in the compressor, the water condenser at the level of which the refrigerant fluid yields calorific energy to the heat transfer fluid of the auxiliary circuit, the first expansion device at the level of which the refrigerant fluid undergoes a first loss of pressure, the external evapo-condenser at the level of which the refrigerant fluid gives up calorific energy in order to defrost, in output of the external evapo-condenser, the refrigerant passes through the seventh junction point before going as needed to the second expansion device and/or to the fourth bypass branch:

• passing through the second expansion device, the refrigerant undergoes a second loss of pressure and the evaporator at which the refrigerant absorbs heat energy from the internal air flow, and
• passing through the fourth expansion device, the refrigerant undergoes a second loss of pressure and the cooler at which the refrigerant absorbs calorific energy from the heat transfer fluid of the auxiliary circuit,

the refrigerant then goes to the compressor.

• en passant par le deuxième dispositif de détente, le fluide réfrigérant subit une deuxième perte de pression et l’évaporateur au niveau duquel le fluide réfrigérant absorbe de l’énergie calorifique du flux d’air interne, et
• en passant par le quatrième dispositif de détente, le fluide réfrigérant subit une deuxième perte de pression et le refroidisseur au niveau duquel le fluide réfrigérant absorbe de l’énergie calorifique du fluide caloporteur du circuit annexe,

According to another aspect of the invention, the reversible air conditioning circuit is configured to operate according to a second defrosting mode in which the refrigerant fluid circulates successively in the compressor, the water condenser at the level of which the refrigerant fluid yields calorific energy to the heat transfer fluid of the auxiliary circuit, the first bypass branch at the level of which the refrigerant fluid yields calorific energy to the internal air flow via the internal condenser, the first expansion device at the level of which the refrigerant fluid undergoes a first loss of pressure, the external evapo-condenser at the level of which the refrigerant fluid yields heat energy in order to defrost, at the outlet of the external evapo-condenser, the refrigerant fluid passes through the seventh junction point before d go as needed to the second expansion device and/or to the fourth bypass branch:

• passing through the second expansion device, the refrigerant undergoes a second loss of pressure and the evaporator at which the refrigerant absorbs heat energy from the internal air flow, and
• passing through the fourth expansion device, the refrigerant undergoes a second loss of pressure and the cooler at which the refrigerant absorbs calorific energy from the heat transfer fluid of the auxiliary circuit,

the refrigerant then goes to the compressor.

According to another aspect of the invention, at the level of the fifth junction point, part of the refrigerant fluid passes through the third expansion device at the level of which the refrigerant fluid undergoes a first loss of pressure and joins the refrigerant fluid coming from the evaporator-condenser at the level of the second junction point.

According to another aspect of the invention, the reversible air conditioning circuit is configured to operate according to a cold start mode in which the refrigerant fluid circulates successively in the compressor, the water condenser at the level of which the refrigerant fluid yields calorific energy to the heat transfer fluid of the auxiliary circuit, the first expansion device at the level of which the refrigerant fluid undergoes a loss of pressure, the external evapo-condenser that the refrigerant fluid passes through with little or no loss of calorific energy, the refrigerant fluid then passing through the fourth expansion device that the refrigerant fluid passes through without loss of pressure and the cooler at which the refrigerant fluid absorbs heat energy from the heat transfer fluid of the auxiliary circuit, the refrigerant fluid then joining the compressor.

Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawings, among which:

shows a schematic representation of a reversible air conditioning circuit,

shows a schematic representation of a reversible air conditioning circuit according to a first mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the first mode of operation of [Fig. 2a],

shows a schematic representation of a reversible air conditioning circuit according to a second mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the second operating mode of [Fig. 3a],

shows a schematic representation of a reversible air conditioning circuit according to a third mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the third operating mode of [Fig. 4a],

shows a schematic representation of a reversible air conditioning circuit according to a fourth mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the fourth operating mode of [Fig. 5a],

shows a schematic representation of a reversible air conditioning circuit according to a fifth mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the fifth operating mode of [Fig. 6a],

shows a schematic representation of a reversible air conditioning circuit according to a sixth mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the sixth operating mode of [Fig. 7a],

shows a schematic representation of a reversible air conditioning circuit according to a seventh mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the seventh operating mode of [Fig. 8a],

shows a schematic representation of a reversible air conditioning circuit according to an eighth mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the eighth operating mode of [Fig. 9a],

shows a schematic representation of a reversible air conditioning circuit according to a ninth mode of operation,

shows a schematic representation of a pressure/enthalpy diagram of the ninth operating mode of [Fig. 10a],

In the various figures, identical elements bear the same reference numbers.

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference is to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined and/or interchanged to provide other embodiments.

In the present description, it is possible to index certain elements or parameters, such as for example first element or second element as well as first parameter and second parameter or even first criterion and second criterion, etc. In this case, it is a simple indexing to differentiate and name elements or parameters or criteria that are close but not identical. This indexing does not imply a priority of one element, parameter or criterion over another and such denominations can easily be interchanged without departing from the scope of the present description. Nor does this indexing imply an order in time, for example, to assess such and such a criterion.

In the present description, “placed upstream” means that one element is placed before another with respect to the direction of circulation of a fluid. Conversely, “placed downstream” means that one element is placed after another in relation to the direction of fluid circulation.

The [Fig. 1] shows a reversible air conditioning circuit 1 in which a refrigerant fluid circulates and comprising a main loop A as well as three bypass branches B, C and D.

• un compresseur 3,
• un condenseur d’eau 5 relié conjointement à un circuit annexe dans lequel circule un fluide caloporteur,
• un premier dispositif de détente 7,
• un évapo-condenseur externe 9 destiné à être traversé par un flux d’air externe 100,
• un deuxième dispositif de détente 15, et
• un évaporateur 17 destiné à être traversé par un flux d’air interne 200.

The main loop A comprises, in the direction of circulation of the refrigerant fluid:

• a compressor 3,
• a water condenser 5 jointly connected to an auxiliary circuit in which a heat transfer fluid circulates,
• a first expansion device 7,
• an external evapo-condenser 9 intended to be crossed by an external air flow 100,
• a second expansion device 15, and
• an evaporator 17 intended to be crossed by an internal air flow 200.

This main loop A is an arbitrarily chosen loop in order to facilitate its description. This main loop A corresponds to the path of the coolant in a reference cooling mode described later in this description.

The first 7 and the second 15 expansion device may more particularly be expansion devices capable of allowing the passage of the refrigerant fluid without loss of pressure. The second expansion device 15 can also have a stop function and allow the blocking of the circulation of the refrigerant fluid.

By flow of external air 100 is meant more particularly a flow of air coming from outside the vehicle. The external evapo-condenser 9 can thus, for example, be arranged on the front face of the motor vehicle at the grille.

By internal air flow 200 is meant more particularly an air flow intended for the passenger compartment of a motor vehicle. The evaporator 17 can for example be arranged within a heating, ventilation and air conditioning (HVAC) device.

By ancillary circuit, we mean a circulation circuit in which a heat transfer fluid, for example water or glycol water circulates. This circuit may include different heat exchangers in order to allow thermal management, for example of batteries and/or electric motors, in particular in the context of a hybrid or electric motor vehicle.

The first bypass branch B connects a first junction point 31 to a second junction point 32. The first junction point 31 is arranged downstream of the water condenser 5, between the condenser 5 and the first expansion device 7. The second junction point 32 is, for its part, arranged upstream of the second expansion device 15, between the external evapo-condenser 9 and the second expansion device 15.

The first bypass branch B comprises in particular an internal condenser 13 intended to be crossed by the internal air flow 200. This internal condenser 13 can in particular be placed downstream of the evaporator 17 in the internal air flow 200.

The second branch C connects a third junction point 33 to a fourth junction point 34. The third junction point 33 is arranged downstream of the external evapo-condenser 9, between said external evapo-condenser 9 and the second junction point 32. The fourth junction point 34 is arranged downstream of the evaporator 17, between said evaporator 17 and the compressor 3.

The third bypass branch D connects a fifth junction point 35 to a sixth junction point 36. The fifth junction point 35 is arranged on the first bypass branch B, downstream of the internal condenser 13, between said internal condenser 13 and the second junction point 32. The sixth junction point 36 is, for its part, disposed downstream of the first junction point 31, between said first junction point 31 and the first expansion device 7.

Between the fifth 35 and the second 32 junction point, the second branch branch also comprises a third expansion device 21. This third expansion device 21 may in particular be a tube orifice placed so as to allow a reduction in the pressure of the fluid refrigerant coming from the internal condenser 13 and going to the second junction point 32.

In order to control and determine the path of the refrigerant fluid, the reversible air conditioning circuit 1 comprises various means for controlling the flow of refrigerant fluid.

In order to determine whether or not the refrigerant fluid circulates in the first bypass branch B, the reversible air conditioning circuit 1 can thus comprise a first shut-off valve 41 arranged on said first bypass branch B and a second shut-off valve 42 arranged on the main loop A, downstream of the first junction point 31, between said first junction point 31 and the sixth junction point 36.

The first bypass branch B may also include a non-return valve 44 arranged between the first shut-off valve 31 and the fifth junction point 35 in order to prevent the refrigerant fluid from rising from the second junction point 32 towards the first. junction point 31.

The second bypass branch C can also include a third shut-off valve 43 in order to allow or not the refrigerant fluid from the external evapo-condenser 9 to pass through it.

The main loop A can also include a non-return valve 45 arranged downstream of the external evapo-condenser 9 between the third junction point 33 and the fifth junction point 35 in order to prevent the refrigerant fluid from rising from the fifth junction point 35 to the third junction point 33.

The third bypass branch D may also include a non-return valve 46 in order to prevent the refrigerant fluid from rising from the sixth junction point 36 to the fifth junction point 35.

The reversible air conditioning circuit 1 may also comprise on the main loop A an internal heat exchanger 19. This internal heat exchanger 19 is in particular configured to allow heat exchanges between the refrigerant fluid at different pressures in different operating modes described later in this description. This internal heat exchanger 19 is more particularly arranged on the one hand between the third 33 and the second 32 junction point and on the other hand between the fourth junction point 34 and the compressor 3.

The reversible air conditioning circuit 1 may also include a refrigerant fluid accumulator 11, for example arranged upstream of the compressor 3. More specifically, this accumulator 11 may be arranged downstream of the fourth junction point 34 between said fourth junction point 34 and the internal heat exchanger 19.

The reversible air conditioning circuit 1 may further comprise a fourth bypass branch E. This fourth bypass branch E is connected parallel to the second expansion device 15 and to the evaporator 17 and connects a seventh junction point 37 to an eighth point junction 38. The seventh junction point 37 is arranged downstream of the second junction point 32, between said second junction point 32 and the second expansion device 15. The eighth junction point 38 is, for its part, arranged downstream of the evaporator 17, between said evaporator 17 and the fourth junction point 34.

The fourth bypass branch E comprises, in the direction of circulation of the coolant fluid, a fourth expansion device 25 and a cooler 23 jointly connected to an auxiliary circuit in which a coolant fluid circulates. The fourth expansion device 25 may more particularly be an expansion device capable of allowing the passage of the refrigerant fluid without loss of pressure. The fourth expansion device 25 can also have a stop function and allow the blocking of the circulation of the refrigerant fluid.

The reversible air conditioning circuit 1 can in particular operate according to different operating modes illustrated in FIGS. 2a, 3a, 4a, 5a, 6a, 7a, 8a, 9a and 10a. In these figures, only the elements in which the heat transfer fluid circulates are shown. In addition, arrows indicate the direction of circulation of the heat transfer fluid.

a) First mode of cooling:

The reversible air conditioning circuit 1 can be configured to operate according to a first cooling mode illustrated in [Fig. 2a]. The [Fig. 2b] shows, for its part, a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

In this first mode of cooling, the refrigerant fluid first passes through compressor 3. At compressor 3, the refrigerant fluid undergoes an increase in its pressure and its enthalpy, as illustrated by curve 300 on the diagram of the [Fig. 2b].

The coolant then passes into the water condenser 5. If this water condenser 5 is in operation, that is to say that it is also crossed by the heat transfer fluid of the auxiliary circuit, the coolant can yield of calorific energy to the coolant, as illustrated by the curve 500 on the diagram of [FIG. 2b]. This can, for example, make it possible to heat the batteries and/or the electric motor in connection with the auxiliary circuit so that they reach an optimum operating temperature. If the water condenser 5 is stopped, that is to say that it is not crossed by the heat transfer fluid from the auxiliary circuit, the refrigerant fluid passes through it without loss of calorific energy to the heat transfer fluid. .

The refrigerant fluid then passes into the first expansion device 7 which it passes through without loss of pressure.

The refrigerant fluid then passes into the external evapo-condenser 9. At the level of the external evapo-condenser 9, the refrigerant fluid yields heat energy to the external air flow 100, as illustrated by the curve 900 on the diagram of [Fig. 2b].

The refrigerant fluid then passes into the second expansion device 15 at the level of which the refrigerant fluid undergoes a loss of pressure, as illustrated by the curve 150 in the diagram of [FIG. 2b].

The refrigerant fluid then passes through the evaporator 17. At the evaporator 17, the refrigerant fluid absorbs heat energy from the internal air flow 200, as illustrated by the curve 170 in the diagram of [Fig. 2b].

The refrigerant fluid then joins the compressor 3 passing in particular through the accumulator 11.

In this first mode of cooling, the presence of the internal heat exchanger 19 can make it possible to increase the coefficient of performance of the reversible air conditioning circuit 1. Indeed, as shown in [FIG. 2a] and curves 190a and 190b of the diagram of [Fig. 2b], the refrigerant fluid at the outlet of the external evapo-condenser 9 transfers part of its enthalpy and therefore of its calorific energy to the refrigerant fluid upstream of the compressor 3.

In order to allow this first mode of cooling, the first 41 and third 43 shut-off valves are closed. The second stop valve 42 is, for its part, open.

If the reversible air conditioning circuit 1 includes a fourth bypass branch E, the fourth expansion device 25 is then closed in order to prevent the circulation of the refrigerant within it.

This first mode of cooling makes it possible to cool the internal air flow 200 by absorbing heat energy at the level of the evaporator 17. This heat energy is transferred to the external air flow 100 at the level of the evapo-condenser external 9.

b) Second cooling world:

The reversible air conditioning circuit 1 can be configured to operate according to a second cooling mode illustrated in [Fig. 3a]. The [Fig. 3b] shows, for its part, a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

This second cooling mode is identical to the first cooling mode with the difference that the reversible air conditioning circuit 1 comprises a fourth bypass branch E inside which the refrigerant fluid circulates parallel to the evaporator 17.

Thus, at the outlet of the external evapo-condenser 9, the refrigerant fluid divides at the level of the seventh junction point 37.

A first part of the refrigerant fluid passes through the second expansion device 15 at the level of which the refrigerant fluid undergoes a loss of pressure, as illustrated on the curve 150 of the diagram of [FIG. 3b]. This first part of the refrigerant fluid then passes through the evaporator 17 at the level of which the refrigerant fluid absorbs calorific energy from the internal air flow 200, as illustrated by the curve 170 of the diagram of [Fig. 3b].

A second part of the refrigerant fluid passes through the fourth expansion device 25 at the level of which the refrigerant fluid undergoes a loss of pressure, as illustrated on the curve 250 of the diagram of [FIG. 3b]. This second part of the coolant fluid then passes through the cooler 23 at which the coolant fluid absorbs calorific energy from the heat transfer fluid of the auxiliary circuit, as illustrated by the curve 230 of the diagram of [Fig. 3b].

The two parts of the refrigerant fluid then join at the level of the eighth junction point 38 before returning to the compressor 3.

In order to allow this second mode of cooling, the first 41 and third 43 shut-off valves are closed. The second stop valve 42 is, for its part, open.

This second mode of cooling makes it possible to cool the internal air flow 200 at the level of the evaporator 17 but also the heat transfer fluid at the level of the cooler 23. The fact of cooling the heat transfer fluid of the annex circuit makes it possible, for example, to cool the batteries and/or the electric motor of a hybrid or electric vehicle.

c) First heat pump mode:

The reversible air conditioning circuit 1 can be configured to operate according to a first heat pump mode illustrated in [FIG. 4a]. The [Fig. 4b] shows, for its part, a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

In this first heat pump mode, the refrigerant fluid first passes through compressor 3. At compressor 3, the refrigerant fluid undergoes an increase in its pressure and its enthalpy, as illustrated by curve 300 on the diagram of the [Fig. 4b].

The coolant then passes into the water condenser 5. If this water condenser 5 is in operation, that is to say that it is also crossed by the heat transfer fluid of the auxiliary circuit, the coolant can yield of calorific energy to the coolant, as illustrated by the curve 500 on the diagram of [FIG. 4b]. This can, for example, make it possible to heat the batteries and/or the electric motor in connection with the auxiliary circuit so that they reach an optimum operating temperature. If the water condenser 5 is stopped, that is to say that it is not crossed by the heat transfer fluid from the auxiliary circuit, the refrigerant fluid passes through it without loss of calorific energy to the heat transfer fluid. .

The heat transfer fluid then passes into the first bypass branch B at which the refrigerant fluid yields calorific energy to the internal air flow 200 via the internal condenser 13, as illustrated by the curve 130 of the diagram of [Fig. . 4b].

The refrigerant fluid then passes through the third bypass branch D, in order to join the first expansion device 7. At the level of the first expansion device 7, the refrigerant fluid undergoes a loss of pressure, as illustrated by the curve 700 of the flow diagram. the [Fig. 4b].

The refrigerant fluid then passes into the external evapo-condenser 9. At the level of the external evapo-condenser 9, the refrigerant fluid absorbs calorific energy from the external air flow 100, as illustrated by the curve 900 of the diagram of [Fig. 4b].

The refrigerant fluid then passes through the second bypass branch C before joining the compressor 3 passing in particular through the accumulator 11.

In this first heat pump mode, the presence of the internal heat exchanger 19 has no influence because it is crossed only by the refrigerant fluid coming from the external evapo-condenser 9.

In order to allow this first heat pump mode, the first 41 and third 43 shut-off valves are open. The second stop valve 42 is, for its part, closed.

The second expansion device 15 is closed in order to prevent the circulation of the refrigerant fluid in the evaporator 13.

If the reversible air conditioning circuit 1 includes a fourth bypass branch E, the fourth expansion device 25 is also closed in order to prevent the circulation of the refrigerant fluid within it.

This first heat pump mode makes it possible to heat the internal air flow 200 at the level of the internal condenser 13, as well as possibly the heat transfer fluid at the level of the water condenser 5, by drawing heat energy from the flow of heat. external air 100 at the level of the evapo-condenser 9.

d) Second heat pump mode:

The reversible air conditioning circuit 1 can be configured to operate according to a second heat pump mode illustrated in [FIG. 5a]. The [Fig. 5b] shows, for its part, a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

In this second heat pump mode, the refrigerant first passes through compressor 3. At compressor 3, the refrigerant undergoes an increase in its pressure and its enthalpy, as illustrated by curve 300 on the diagram of the [Fig. 5b].

The refrigerant fluid then passes into the water condenser 5 which is in operation, i.e. it is also crossed by the heat transfer fluid from the additional circuit. The refrigerant fluid then transfers heat energy to the heat transfer fluid, as illustrated by curve 500 in the diagram of [Fig. 5b].

The refrigerant fluid then passes through the first expansion device 7. At the level of the first expansion device 7, the refrigerant fluid undergoes a loss of pressure, as illustrated by the curve 700 of the diagram of [FIG. 5b].

The refrigerant fluid then passes into the external evapo-condenser 9. At the level of the external evapo-condenser 9, the refrigerant fluid absorbs calorific energy from the external air flow 100, as illustrated by the curve 900 of the diagram of [Fig. 5b].

The refrigerant fluid then passes through the second bypass branch C before joining the compressor 3 passing in particular through the accumulator 11.

In this second heat pump mode, the presence of the internal heat exchanger 19 has no influence because it is crossed only by the refrigerant fluid coming from the external evapo-condenser 9.

In order to allow this second heat pump mode, the second 42 and third 43 shut-off valves are open. The first stop valve 41 is, for its part, closed.

The second expansion device 15 is closed in order to prevent the circulation of the refrigerant fluid in the evaporator 13.

If the reversible air conditioning circuit 1 includes a fourth bypass branch E, the fourth expansion device 25 is also closed in order to prevent the circulation of the refrigerant fluid within it.

This second heat pump mode makes it possible to heat only the heat transfer fluid at the level of the water condenser 5 by drawing heat energy from the external air flow 100 at the level of the evapo-condenser 9.

e) Dehumidification mode:

The reversible air conditioning circuit 1 can be configured to operate according to a dehumidification mode illustrated in [FIG. 6a]. The [Fig. 6b] shows a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

In this dehumidification mode, the refrigerant first passes through compressor 3. At compressor 3, the refrigerant undergoes an increase in its pressure and its enthalpy, as illustrated by curve 300 on the diagram in [ Fig. 6b].

The coolant then passes into the water condenser 5. If this water condenser 5 is in operation, that is to say that it is also crossed by the heat transfer fluid of the auxiliary circuit, the coolant can yield of calorific energy to the coolant, as illustrated by the curve 500 on the diagram of [FIG. 6b]. This can, for example, make it possible to heat the batteries and/or the electric motor in connection with the auxiliary circuit so that they reach an optimum operating temperature. If the water condenser 5 is stopped, that is to say that it is not crossed by the heat transfer fluid from the auxiliary circuit, the refrigerant fluid passes through it without loss of calorific energy to the heat transfer fluid. .

The heat transfer fluid then passes into the first bypass branch B at which the refrigerant fluid yields calorific energy to the internal air flow 200 via the internal condenser 13, as illustrated by the curve 130 of the diagram of [Fig. . 6b].

The coolant then splits at the fifth junction point 35.

A first part of the refrigerant fluid passes through the third bypass branch D in order to reach the first expansion device 7. At the first expansion device 7, the refrigerant fluid undergoes a loss of pressure, as illustrated by the curve 700 of the flow diagram. Figure 6d.

The refrigerant fluid then passes into the external evapo-condenser 9 at the level of which it absorbs calorific energy from the external air flow 100, as illustrated by the curve 900 of the diagram of [Fig. 6b].

The refrigerant fluid then passes into the second bypass branch C.

A second part of the refrigerant fluid passes through the third expansion device 21 at the level of which it undergoes a first loss of pressure, as illustrated by the curve 210 of the diagram of [Fig. 6b].

The refrigerant fluid then passes into the second expansion device 15 at the level of which it undergoes a second loss of pressure, as illustrated by the curve 150 of the diagram of [FIG. 6b].

The refrigerant fluid then passes through the evaporator 17 at which the refrigerant fluid absorbs heat energy from the internal air flow 200, as illustrated by the curve 170 of the diagram of [Fig. 6b].

The two parts of the refrigerant fluid join at the level of the fourth junction point 34 before returning to the compressor 3 passing in particular through the accumulator 11.

In this mode of dehumidification, the presence of the third expansion device 21 allows the refrigerant fluid arriving at the level of the second 15 and fourth 25 expansion devices to be at an intermediate pressure, lower than the pressure at the outlet of the compressor 3. This thus allows to use, for example, second 15 and fourth 25 expansion devices having less resistance to pressure and therefore potentially less expensive.

In this dehumidification mode, the presence of the internal heat exchanger 19 has no effect because it is only crossed by the refrigerant coming from the fourth junction point 34.

In order to allow this mode of dehumidification, the first 41 and third 43 shut-off valves are opened. The second stop valve 42 is, for its part, closed. If the reversible air conditioning circuit 1 includes a fourth bypass branch E, the fourth expansion device 25 is also closed in order to prevent the circulation of the refrigerant fluid within it.

This dehumidification mode makes it possible in particular to dehumidify the internal air flow 200 by cooling it at the level of the evaporator 17 then by heating it at the level of the internal condenser 13. This dehumidification mode is particularly useful and effective for a temperature of outdoor air above 0°C.

f) First defrost mode:

The reversible air conditioning circuit 1 can be configured to operate according to a first defrosting mode illustrated in [FIG. 7a]. The [Fig. 7b] shows, for its part, a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

In this first defrosting mode, the refrigerant fluid first passes through compressor 3. At compressor 3, the refrigerant fluid undergoes an increase in its pressure and its enthalpy, as illustrated by curve 300 on the diagram of the [Fig. 7b].

The refrigerant fluid then passes into the water condenser 5 which is in operation, i.e. it is also crossed by the heat transfer fluid from the additional circuit. The refrigerant fluid then transfers heat energy to the heat transfer fluid, as illustrated by curve 500 in the diagram of [Fig. 7b].

The refrigerant fluid then passes through the first expansion device 7. At the level of the first expansion device 7, the refrigerant fluid undergoes a first loss of pressure, as illustrated by the curve 700 of the diagram of [FIG. 7b].

The refrigerant fluid then passes into the external evapo-condenser 9. At the level of the external evapo-condenser 9, the refrigerant fluid releases calorific energy from the external air flow 100, as illustrated by the curve 900 of the diagram of [Fig. 7b]. At the level of the external evapo-condenser 9, the external air flow 100 is more particularly stopped, that is to say that it does not cross said external evapo-condenser 9, for example by means of a device for front face shutter. Thus the calorific energy released at the level of the external evapo-condenser 9 is used to melt the frost present on this heat exchanger.

At the outlet of the external evapo-condenser 9, the refrigerant fluid passes through the seventh junction point 37 before going as needed to the second expansion device 15 and/or to the fourth bypass branch E.

Passing through the second expansion device 15, the refrigerant undergoes a second loss of pressure, as illustrated on the curve 150 of the diagram of [FIG. 7b]. The refrigerant fluid then passes through the evaporator 17 at the level of which it absorbs calorific energy from the internal air flow 200, as illustrated by the curve 170 of the diagram of [Fig. 7b].

Passing through the fourth expansion device 25, the refrigerant fluid also undergoes a second loss of pressure, as illustrated on the curve 250 of the diagram of [FIG. 7b]. The refrigerant then passes through the cooler 23 at which the refrigerant absorbs calorific energy from the heat transfer fluid of the auxiliary circuit, as illustrated by the curve 230 of the diagram of [Fig. 7b].

The refrigerant fluid then joins the compressor 3 passing in particular through the accumulator 11.

In this first defrosting mode, the presence of the internal heat exchanger 19 can make it possible to increase the coefficient of performance of the reversible air conditioning circuit 1. Indeed, as shown in [FIG. 7a] and curves 190a and 190b of the diagram of [Fig. 7b], the refrigerant fluid at the outlet of the external evapo-condenser 9 transfers part of its enthalpy and therefore of its calorific energy to the refrigerant fluid upstream of the compressor 3.

In order to allow this first defrosting mode, the first 41 and third 43 shut-off valves are closed. The second stop valve 42 is, for its part, open.

So that the refrigerant passes only through the evaporator 17, the fourth expansion device 25 is closed.

In order for the coolant to pass only through the fourth bypass branch E, the second expansion device 15 is closed.

This first defrosting mode makes it possible to defrost the frost formed at the level of the external evapo-condenser 9, for example during operation in heat pump mode, by absorbing calorific energy in the internal air flow 100 at the level of the evaporator 17 and/or by absorbing calorific energy from the coolant of the auxiliary circuit at the level of the cooler 23.

g) Second defrost mode:

The reversible air conditioning circuit 1 can be configured to operate according to a second defrosting mode illustrated in [FIG. 8a]. The [Fig. 8b] shows, for its part, a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

In this second defrosting mode, the refrigerant first passes through compressor 3. At compressor 3, the refrigerant undergoes an increase in its pressure and its enthalpy, as illustrated by curve 300 on the diagram of the [Fig. 8b].

The refrigerant fluid then passes into the water condenser 5 which is in operation, i.e. it is also crossed by the heat transfer fluid from the additional circuit. The refrigerant fluid then transfers heat energy to the heat transfer fluid, as illustrated by curve 500 in the diagram of [Fig. 8b].

The heat transfer fluid then passes into the first bypass branch B at which the refrigerant fluid yields calorific energy to the internal air flow 200 via the internal condenser 13, as illustrated by the curve 130 of the diagram of [Fig. . 8b].

The refrigerant fluid then passes through the third bypass branch D, in order to join the first expansion device 7. At the level of the first expansion device 7, the refrigerant fluid undergoes a loss of pressure, as illustrated by the curve 700 of the flow diagram. the [Fig. 8b].

The refrigerant fluid then passes into the external evapo-condenser 9. At the level of the external evapo-condenser 9, the refrigerant fluid releases calorific energy from the external air flow 100, as illustrated by the curve 900 of the diagram of [Fig. 8b]. At the level of the external evapo-condenser 9, the external air flow 100 is more particularly stopped, that is to say that it does not cross said external evapo-condenser 9, for example by means of a device for front face shutter. Thus the calorific energy released at the level of the external evapo-condenser 9 is used to melt the frost present on this heat exchanger.

At the outlet of the external evapo-condenser 9, the refrigerant passes through the seventh junction point 37 before going as needed to the second expansion device 15 and/or to the fourth bypass branch E.

Passing through the second expansion device 15, the refrigerant undergoes a second loss of pressure, as illustrated on the curve 150 of the diagram of [FIG. 8b]. The refrigerant fluid then passes through the evaporator 17 at the level of which it absorbs calorific energy from the internal air flow 200, as illustrated by the curve 170 of the diagram of [Fig. 8b].

Passing through the fourth expansion device 25, the refrigerant fluid also undergoes a second loss of pressure, as illustrated on the curve 250 of the diagram of [FIG. 8b]. The refrigerant fluid then passes through the cooler 23 at which the refrigerant fluid absorbs heat energy from the heat transfer fluid of the auxiliary circuit, as illustrated by the curve 230 of the diagram of [Fig. 8b].

The refrigerant fluid then joins the compressor 3 passing in particular through the accumulator 11.

In this first defrosting mode, the presence of the internal heat exchanger 19 can make it possible to increase the coefficient of performance of the reversible air conditioning circuit 1. Indeed, as shown in [FIG. 8a] and curves 190a and 190b of the diagram of [Fig. 8b], the refrigerant fluid at the outlet of the external evapo-condenser 9 transfers part of its enthalpy and therefore of its calorific energy to the refrigerant fluid upstream of the compressor 3.

In order to allow this first defrosting mode, the second 42 and third 43 shut-off valves are closed. The first shut-off valve 41 is, for its part, open.

So that the refrigerant passes only through the evaporator 17, the fourth expansion device 25 is closed.

In order for the coolant to pass only through the fourth bypass branch E, the second expansion device 15 is closed.

In this second defrosting mode, the third expansion device 21 is preferably capable of being closed so as not to allow the refrigerant fluid to circulate between the fifth 35 and the second 32 junction point.

This second defrosting mode makes it possible to defrost the frost formed at the level of the external evapo-condenser 9, for example during operation in heat pump mode, by absorbing calorific energy in the internal air flow 100 at the level of the evaporator 17 and/or by absorbing calorific energy from the heat transfer fluid of the auxiliary circuit at the level of the cooler 23. In addition, this second defrosting mode makes it possible to limit the arrival of a flow of air internal 200 cold in the passenger compartment and also to dehumidify it in a certain way. Indeed, the internal air flow 200 is initially cooled at the level of the evaporator 17 then heated at the level of the internal condenser 13.

h) Third defrost mode

The reversible air conditioning circuit 1 can be configured to operate according to a third defrosting mode illustrated in [FIG. 9a]. The [Fig. 9b] shows, for its part, a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

This third defrosting mode is identical to the second defrosting mode described above except that at the level of the fifth junction point 35, part of the refrigerant fluid passes through the third expansion device 21. At the level of the third expansion 21 the refrigerant undergoes a first loss of pressure and joins the refrigerant from the evapo-condenser 9 at the second junction point 32.

In this third mode of defrosting, the third expansion device 21 is preferably a tube orifice calibrated to allow a loss of pressure of the refrigerant fluid of the order of that applied by the first expansion device 7.

i) Cold start mode:

The reversible air conditioning circuit 1 can be configured to operate according to a cold start mode illustrated in [FIG. 10a]. The [Fig. 10b] shows, for its part, a pressure (expressed in Pascal Pa) / enthalpy (expressed in kJ/kg) diagram of the evolution of the pressure and the enthalpy of the refrigerant fluid during its circulation and when it crosses different elements.

In this cold start mode, the refrigerant first passes through compressor 3. At compressor 3, the refrigerant undergoes an increase in its pressure and its enthalpy, as illustrated by curve 300 on the the [Fig. 10b].

The refrigerant fluid then passes into the water condenser 5 which is in operation, i.e. it is also crossed by the heat transfer fluid from the additional circuit. The refrigerant fluid then transfers heat energy to the heat transfer fluid, as illustrated by curve 500 in the diagram of [Fig. 10b].

The refrigerant fluid then passes through the first expansion device 7. At the level of the first expansion device 7, the refrigerant fluid undergoes a loss of pressure, as illustrated by the curve 700 of the diagram of [FIG. 10b].

The refrigerant fluid then passes into the external evapo-condenser 9. At the external evapo-condenser 9, the refrigerant fluid loses little or no heat energy from the external air flow 100, as illustrated by the curve 900 of the diagram of [Fig. 10b]. Indeed, the external air flow 100 is stopped, that is to say that it does not cross the external evapo-condenser 9, for example by means of a front face closing device.

The refrigerant fluid then passes into the fourth bypass branch E and passes through the fourth expansion device 25 which it passes through without loss of pressure.

The refrigerant fluid then passes through cooler 23. At this cooler 23, the refrigerant fluid absorbs heat energy from the heat transfer fluid of the auxiliary circuit, as illustrated by curve 230 of the diagram of [Fig. 10b].

The refrigerant fluid then goes to compressor 3.

In this cold start mode, the presence of the internal heat exchanger 19 has no effect because the refrigerant fluid passing through said internal heat exchanger 19 at the outlet of the external evapo-condenser 9 and the refrigerant fluid arriving at the compressor 3 have a relatively identical pressure preventing exchanges of enthalpy from one to the other.

In order to allow this cold start mode, the first 41 and third 43 shut-off valves are closed. The second stop valve 42 is, for its part, open.

In order for the coolant to pass through the fourth bypass branch E, the second expansion device 15 is closed.

This cold start mode makes it possible during a cold start of the motor vehicle, that is to say in which all the elements and fluids of the motor vehicle are at a temperature close to or equal to the ambient temperature, to quickly increase the pressure of the refrigerant in order to subsequently switch to a cooling mode.

This cold start mode also makes it possible to limit the pressure within the internal condenser 13 by a phenomenon of suction of the refrigerant fluid illustrated by the arrows in [Fig. 8a]. This thus makes it possible to limit the pressure within this internal condenser 13 during the cooling mode following this cold start mode.

Indeed, for a refrigerant of chemical or organic type such as R134a, in a cooling mode, the high pressure is of the order of 5 to 26 bar. By high pressure is meant here the pressure of the refrigerant fluid downstream of the compressor 3, between said compressor 3 and the second 15 and/or fourth 25 expansion device at the level of which it undergoes a loss of pressure. The low pressure is, for its part, of the order of 3 to 4 bar. By low pressure is meant here the pressure upstream of the compressor 3, between the second 15 and/or fourth 25 expansion device and said compressor 3. The pressure within the internal condenser 13 is, for its part, limited between 2 and 5 bar.

Indeed, for an inorganic type refrigerant fluid such as R744, in a cooling mode, the high pressure is of the order of 50 to 130 bar. The low pressure is, for its part, of the order of 35 to 55 bar. The pressure within the internal condenser 13 is, for its part, limited between 25 and 35 bar.

Thus, it is clear that the reversible air conditioning circuit 1 according to the invention by virtue of its architecture allows operation according to a multitude of operating modes which can be in accordance with the requirements of the manufacturers and the needs of the users.

Claims (10)

Reversible air conditioning circuit (1) in which a refrigerant fluid circulates and comprising:

• a main loop (A) comprising, in the direction of circulation of the refrigerant fluid, a compressor (3), a water condenser (5) jointly connected to an auxiliary circuit in which a heat transfer fluid circulates, a first expansion device (7 ), an external evapo-condenser (9) intended to be crossed by an external air flow (100), a second expansion device (15), and an evaporator (17) intended to be crossed by an air flow internal (200),
• a first bypass branch (B) comprising an internal condenser (13) intended to be crossed by an internal air flow (200), said first bypass branch (B) connecting a first junction point (31) arranged downstream of the water condenser (5), between said condenser (5) and the first expansion device (7), at a second junction point (32) arranged upstream of the second expansion device (15), between the evaporator -external condenser (9) and said second expansion device (15),
• a second bypass branch (C) connecting a third junction point (33) disposed downstream of the external evapo-condenser (9), between said external evapo-condenser (9) and the second junction point (32), at a fourth junction point (34) disposed downstream of the evaporator (17), between said evaporator (17) and the compressor (3),
• a third branch branch (D) connecting a fifth junction point (35) disposed on the first branch branch (B) downstream of the internal condenser (13) to a sixth junction point (36) disposed downstream of the first branch junction (31), between said first junction point (31) and the first expansion device (7), and
• a second expansion device (21) disposed on the first branch branch (B) downstream of the fifth junction point (35) between said fifth junction point (35) and the second junction point (32).

Reversible air conditioning circuit (1) according to the preceding claim, characterized in that the main loop (A) comprises an internal heat exchanger (19) configured to allow heat exchanges between the refrigerant fluid at different pressures, said heat exchanger internal heat (19) being arranged on the one hand between the third (33) and the second (32) junction point and on the other hand between the fourth junction point (34) and the compressor (3). Reversible air conditioning circuit (1) according to one of Claims 1 or 2, characterized in that it is configured to operate according to a first heat pump mode in which the refrigerant fluid circulates successively in the compressor (3), the condenser of water (5), the first bypass branch (B) at which the refrigerant fluid transfers heat energy to the internal air flow (200) via the internal condenser (13), the refrigerant fluid then passes by the third bypass branch (D), the first expansion device (7) at the level of which the refrigerant fluid undergoes a loss of pressure, the external evapo-condenser (9) at the level of which the refrigerant fluid absorbs energy calorific value of the external air flow (100), the refrigerant fluid then passes through the second bypass branch (C) before joining the compressor (3). Reversible air conditioning circuit (1) according to one of Claims 1 or 2, characterized in that it is configured to operate according to a second heat pump mode in which the refrigerant fluid circulates successively in the compressor (3), the condenser of water (5) at the level of which the refrigerating fluid yields calorific energy to the heat transfer fluid of the auxiliary circuit, the first expansion device (7) at the level of which the refrigerating fluid undergoes a pressure loss, the evapo-condenser (9) at which the refrigerant fluid absorbs calorific energy from the external air flow (100), the refrigerant fluid then passes through the second bypass branch (C) before joining the compressor (3). Reversible air conditioning circuit (1) according to one of Claims 1 or 2, characterized in that it is configured to operate according to a dehumidification mode in which the refrigerant fluid circulates successively in the compressor (3), the condenser water (5), the first bypass branch (B) at which the refrigerant fluid transfers heat energy to the internal air flow (200) via the internal condenser (13), the refrigerant fluid then divides at the level of the fifth junction point (35):

• a first part of the refrigerant fluid passes through the third bypass branch (D), the first expansion device (7) at the level of which the refrigerant fluid undergoes a loss of pressure, the external evapo-condenser (9) at the level of which it absorbs heat energy from the external airflow (100), the second bypass branch (C), and
• a second part of the refrigerant passes through the third expansion device (21) at which the refrigerant undergoes a first pressure loss and through the second expansion device (15) at which the refrigerant undergoes a second pressure loss , the refrigerant fluid then passes through the evaporator (17) at which the refrigerant fluid absorbs heat energy from the internal air flow (200),

the two parts of the refrigerant fluid joining at the fourth junction point (34) before returning to the compressor (3). Reversible air conditioning circuit (1) according to one of the preceding claims, characterized in that it further comprises a fourth bypass branch (E) comprising, in the direction of circulation of the refrigerant fluid, a fourth expansion device (25) and a cooler (23) jointly connected to a heat transfer fluid circuit, said fourth branch (E) connecting a seventh junction point (37) arranged downstream of the second junction point (32), between said second junction point junction (32) and the second expansion device (15) at an eighth junction point (38) disposed downstream of the evaporator (17), between said evaporator (17) and the fourth junction point (34). Reversible air conditioning circuit (1) according to Claim 6, characterized in that it is configured to operate according to a first defrosting mode in which the refrigerant fluid circulates successively in the compressor (3), the water condenser (5) at the level of which the refrigerant fluid yields calorific energy to the heat transfer fluid of the auxiliary circuit, the first expansion device (7) at the level of which the refrigerant fluid undergoes a first loss of pressure, the external evapo-condenser (9) at the level at which the refrigerant fluid yields calorific energy in order to defrost, at the outlet of the external evapo-condenser (9), the refrigerant fluid passes through the seventh junction point (37) before going as required to the second expansion device (15) and/or to the fourth bypass branch (E):

• passing through the second expansion device (15), the refrigerant undergoes a second loss of pressure and the evaporator (17) at which the refrigerant absorbs heat energy from the internal air flow (200), and
• passing through the fourth expansion device (25), the refrigerant undergoes a second loss of pressure and the cooler (23) at which the refrigerant absorbs calorific energy from the heat transfer fluid of the auxiliary circuit,

the refrigerant fluid then joins the compressor (3). Reversible air conditioning circuit (1) according to Claim 6, characterized in that it is configured to operate according to a second defrosting mode in which the refrigerant fluid circulates successively in the compressor (3), the water condenser (5) at the level of which the refrigerant fluid yields heat energy to the heat transfer fluid of the auxiliary circuit, the first bypass branch (B) at the level of which the refrigerant fluid yields heat energy to the internal air flow (200) via the internal condenser (13), the first expansion device (7) at the level of which the refrigerant fluid undergoes a first loss of pressure, the external evapo-condenser (9) at the level of which the refrigerant fluid yields calorific energy in order to defrost, at the outlet of the external evapo-condenser (9), the refrigerant fluid passes through the seventh junction point (37) before going as needed to the second expansion device (15) and/or to the fourth branch of derivation (E):

• passing through the second expansion device (15), the refrigerant undergoes a second loss of pressure and the evaporator (17) at which the refrigerant absorbs heat energy from the internal air flow (200), and
• passing through the fourth expansion device (25), the refrigerant undergoes a second loss of pressure and the cooler (23) at which the refrigerant absorbs calorific energy from the heat transfer fluid of the auxiliary circuit,

the refrigerant fluid then joins the compressor (3). Reversible air conditioning circuit (1) according to the preceding claim, characterized in that at the level of the fifth junction point (35), part of the refrigerant fluid passes through the third expansion device (21) at the level of which the refrigerant fluid undergoes a first loss of pressure and joins the refrigerant from the evapo-condenser (9) at the second junction point (32). Reversible air conditioning circuit (1) according to Claim 6, characterized in that it is configured to operate according to a cold start mode in which the refrigerant fluid circulates successively in the compressor (3), the water condenser (5 ) at the level of which the refrigerant fluid yields heat energy to the heat transfer fluid of the auxiliary circuit, the first expansion device (7) at the level of which the refrigerant fluid undergoes a pressure loss, the external evapo-condenser (9) that the refrigerant passes through with little or no loss of heat energy, the refrigerant then passes through the fourth expansion device (25) through which the refrigerant passes without loss of pressure and the cooler (23) at which the refrigerant absorbs heat energy from the heat transfer fluid of the auxiliary circuit, the refrigerant fluid then joining the compressor (3).