FR2990264A1

FR2990264A1 - INSTALLATION FOR HEATING, VENTILATION AND / OR AIR CONDITIONING WITH REDUCED CIRCULATING MASS.

Info

Publication number: FR2990264A1
Application number: FR1254111A
Authority: FR
Inventors: Mohamed Yahia
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2012-05-04
Filing date: 2012-05-04
Publication date: 2013-11-08
Anticipated expiration: 2032-05-04
Also published as: WO2013164439A1; FR2990264B1; EP2844934A1

Abstract

L'invention concerne une installation de chauffage, ventilation et/ou climatisation (1) comprenant une boucle de climatisation (8), à l'intérieur de laquelle circule un fluide réfrigérant, un premier circuit de fluide caloporteur (25), à l'intérieur duquel circule un fluide caloporteur, la boucle de climatisation (8) et le premier circuit de fluide caloporteur (25) étant interconnectés par l'intermédiaire d'au moins un deuxième échangeur de chaleur (24) comprenant un premier circuit (40), parcouru par le fluide réfrigérant et relié à la boucle de climatisation (8), et un deuxième circuit (41), parcouru par le fluide caloporteur et relié au premier circuit de fluide caloporteur (25), afin d'assurer un échange thermique entre le fluide réfrigérant et le fluide caloporteur. Selon la présente invention, la circulation du fluide réfrigérant dans le premier circuit (40) du deuxième échangeur de chaleur (24) est co-courante avec la circulation du fluide caloporteur dans le deuxième circuit (41) du deuxième échangeur de chaleur (24).The invention relates to a heating, ventilation and / or air conditioning system (1) comprising an air-conditioning loop (8), inside which a cooling fluid circulates, a first heat-transfer fluid circuit (25), to inside which circulates a coolant, the air conditioning loop (8) and the first coolant circuit (25) being interconnected via at least one second heat exchanger (24) comprising a first circuit (40), through the cooling fluid and connected to the air conditioning loop (8), and a second circuit (41), traversed by the coolant and connected to the first coolant circuit (25), to ensure a heat exchange between the refrigerant and the coolant. According to the present invention, the circulation of the refrigerant in the first circuit (40) of the second heat exchanger (24) is co-current with the circulation of the coolant in the second circuit (41) of the second heat exchanger (24) .

Description

Installation de chauffage, ventilation et/ou climatisation à masse circulante réduite. Le domaine technique de la présente invention est celui des installations de chauffage, ventilation et/ou climatisation utilisées pour conditionner un flux d'air diffusé dans un habitacle de véhicule automobile. Plus particulièrement, l'invention vise une installation de chauffage, ventilation et/ou climatisation comprenant au moins un circuit de fluide caloporteur et une boucle de climatisation, dans laquelle circule un fluide réfrigérant et susceptible au moins de fonctionner dans un mode de fonctionnement dit "refroidissement" et dans un mode de fonctionnement dit "chauffage" ou "pompe à chaleur". La boucle de climatisation comprend classiquement un compresseur, un échangeur de chaleur extérieur, apte à fonctionner en tant que condenseur ou refroidisseur de gaz ou en tant qu'évaporateur, un détendeur et un évaporateur parcourus par le fluide réfrigérant. L'évaporateur est logé dans un boîtier de l'installation de chauffage, ventilation et/ou climatisation généralement agencé dans l'habitacle du véhicule, afin de fournir un flux d'air intérieur à température désirée en fonction d'une demande de l'utilisateur du véhicule. L'échangeur de chaleur extérieur est classiquement installé en face avant du véhicule, afin d'être traversé par un flux d'air extérieur au véhicule. Par ailleurs, la boucle de climatisation peut être combinée à un circuit de fluide caloporteur formant une boucle intermédiaire, destinée à transporter les calories entre un échangeur de chaleur de type "fluide réfrigérant/fluide caloporteur" installé dans la boucle de climatisation et un échangeur de chaleur de type "fluide caloporteur/air" agencé dans le boîtier de l'installation de chauffage, ventilation et/ou climatisation. Heating, ventilation and / or air conditioning system with reduced circulating mass. The technical field of the present invention is that of heating, ventilation and / or air conditioning systems used to condition a flow of air diffused into a passenger compartment of a motor vehicle. More particularly, the invention relates to a heating, ventilation and / or air conditioning system comprising at least one coolant circuit and an air conditioning loop, in which a coolant circulates and can at least operate in a mode of operation called " cooling "and in an operating mode called" heating "or" heat pump ". The air conditioning loop conventionally comprises a compressor, an outdoor heat exchanger, able to function as a condenser or gas cooler or as an evaporator, a pressure reducer and an evaporator traversed by the refrigerant. The evaporator is housed in a housing of the heating, ventilation and / or air conditioning system generally arranged in the passenger compartment of the vehicle, in order to provide an interior air flow at the desired temperature according to a request from the vehicle user. The external heat exchanger is conventionally installed on the front of the vehicle, in order to be traversed by a flow of air outside the vehicle. Furthermore, the air conditioning loop can be combined with a heat transfer fluid circuit forming an intermediate loop, intended to transport the heat between a heat exchanger type "coolant / heat transfer fluid" installed in the air conditioning loop and a heat exchanger. heat of "heat transfer fluid / air" type arranged in the housing of the heating, ventilation and / or air conditioning system.

II est connu d'utiliser la boucle de climatisation dans un mode de fonctionnement dit "refroidissement" ou dans un mode de fonctionnement dit "chauffage". It is known to use the air conditioning loop in an operating mode called "cooling" or in a mode of operation called "heating".

Claims

REVENDICATIONS1. In the operating mode called "cooling", CLAIMS1. In the operating mode called "cooling", the refrigerant is circulated by the compressor and is sent to the external heat exchanger, in which it is cooled by heat exchange with the outside air flow. As a result, the coolant flows to the expander, in which it undergoes a lowering of pressure, before entering the heat exchanger type "coolant / coolant". The refrigerant fluid passing through the heat exchanger of the "coolant / heat transfer fluid" type is then heated by the heat transfer fluid circulating in the heat transfer fluid circuit, which results in a cooling of the coolant and, correspondingly, by cooling. of the interior air flow in order to cool the passenger compartment of the vehicle. The air conditioning loop being a closed circuit, the refrigerant then returns to the compressor. In the so-called "heating" operating mode, the fluid is circulated by the compressor and then sent to the "coolant / heat transfer fluid" type heat exchanger. The refrigerant flowing through the heat exchanger of the "coolant / heat transfer fluid" type is then cooled by the heat transfer fluid circulating in the heat transfer fluid circuit, which results in a heating of the coolant and, correspondingly, by cooling. of the interior air flow in order to warm the passenger compartment of the vehicle. As a result, the coolant flows to the expander, in which it undergoes a lowering of pressure, before entering the external heat exchanger. The air conditioning loop being a closed circuit, the refrigerant then returns to the compressor. In the so-called "cooling" mode of operation, the "refrigerant / heat transfer fluid" type heat exchanger behaves as an evaporator, cooling the heat transfer fluid sent to the "heat transfer fluid / air" type heat exchanger. arranged in the housing of the heating, ventilation and / or air conditioning system. In the so-called "heating" mode of operation, the "refrigerant / heat transfer fluid" type heat exchanger behaves like a condenser, by heating the heat transfer fluid sent to the "heat transfer fluid / air" heat exchanger arranged in the housing of the heating, ventilation and / or air conditioning system. The amount of refrigerant contained in the air conditioning loop is influenced by the operating mode called "cooling" and the operating mode called "heating", as well as by the internal volume of each of the constituent components of the air conditioning loop. In the operating mode called "heating", the average density of the refrigerant flowing through the heat exchanger of "coolant / heat transfer fluid" type is high, which results in a large circulating mass inside the -this. To reduce such a circulating mass, it may be envisaged to reduce the internal volume of the heat exchanger type "coolant / coolant". Such a reduction in the internal volume is then accompanied by an increase in the pressure losses, refrigerant side, resulting in a reduction in heat exchange performance between the coolant and the coolant within the heat exchanger. heat of type "coolant / coolant". To counteract such a drop in performance, the air-conditioning loop specialist has general knowledge that it is necessary to organize the circulation of the refrigerant fluid with respect to the circulation of the heat transfer fluid so that they can be countercurrent inside the heat exchanger type "coolant / coolant". The subject of the invention is therefore a heating, ventilation and / or air-conditioning installation comprising an air-conditioning loop, inside which a coolant circulates and a first heat-transfer fluid circuit, inside which a heat transfer fluid circulates. . Furthermore, the air conditioning loop and the first heat transfer fluid circuit are interconnected via at least one heat exchanger, called second heat exchanger, comprising a first circuit, traversed by the refrigerant and connected to the loop. declimatization, and a second circuit, traversed by the coolant and connected to the first coolant circuit, to ensure a heat exchange between the coolant and the heat transfer fluid. The heating, ventilation and / or air conditioning system is thus arranged so that the refrigerant can capture or deliver heat to the heat transfer fluid via the second heat exchanger. More particularly, according to the present invention, the circulation of the refrigerant in the first circuit of the second heat exchanger is co-current with the circulation of the coolant in the second circuit of the second heat exchanger. The invention proposes a heating, ventilation and / or air-conditioning installation comprising an air-conditioning loop and a heat-transfer fluid circuit, the arrangement of which goes against the common arrangements provided by the air-conditioning loop specialist, by choosing a circulation at co-current of the coolant and heat transfer fluid inside the heat exchanger disposed in the air conditioning loop and the coolant circuit, that is to say the second heat exchanger. In addition, according to the present invention, the heat transfer fluid circuit is arranged to flood the second heat exchanger when the heating, ventilation and / or air conditioning system is used in the so-called "cooling" operating mode. Advantageously, the air conditioning circuit comprises a means for fixing the refrigerant fluid, in particular configured so that the refrigerant fluid is less than 80% at the outlet of the first circuit of the second heat exchanger, especially when the refrigerant collects refrigerant. heat of the heat transfer fluid through the second heat exchanger, that is to say when the heating, ventilation and / or air conditioning system is configured in the operating mode called "cooling". It is thus understood that the present invention proposes to circulate the coolant and heat transfer fluid in the same direction inside the second heat exchanger, and set the title of the refrigerant at the outlet of the second heat exchanger. The evaporation phase is thus completed by another component of the air conditioning loop, which significantly reduces the volume of the portion of the second heat exchanger traversed by the refrigerant. Advantageously, the air conditioning loop comprises at least one compressor, an expansion member, said first expansion member, a coolant storage device and at least one internal heat exchanger, able to achieve a heat exchange between an upper part. pressure of the air conditioning loop between the compressor and the first expansion member and a low pressure portion of the air conditioning loop between the first expansion member and the compressor. In addition, advantageously, the internal heat exchanger comprises the storage device. According to a first exemplary embodiment, the means for fixing the title of the refrigerant fluid is integrated with the storage device. Preferably, such a means for fixing the refrigerant fluid's titer is formed by a device for collecting the refrigerant fluid in the liquid state contained in the storage device. According to the first exemplary embodiment, the means for fixing the refrigerant fluid titer is configured so that the titer of the coolant in a portion of the internal heat exchanger traversed by the refrigerant fluid at low pressure increases from 80%. According to a second exemplary embodiment, the means for fixing the refrigerant fluid's titre is integrated into the internal heat exchanger comprising a first portion traversed by the high-pressure refrigerant fluid and a second portion traversed by the low-pressure refrigerant fluid, the second portion. According to the second exemplary embodiment, the second portion of the internal heat exchanger is formed by a first sub-portion and a second sub-portion, separated by the storage device. Preferably, the internal heat exchanger, the storage device and the second heat exchanger are integral with each other so as to form a unitary module. Advantageously, the unitary module comprises at most four passages through which the refrigerant enters or leaves the unitary module. Advantageously, the unitary module comprises a single heat transfer fluid inlet and a single heat transfer fluid outlet. Finally, note that the use of a supercritical refrigerant fluid, such as carbon dioxide, is particularly advantageous for the heating, ventilation and / or air conditioning system according to the present invention. According to an additional feature of the present invention, the second heat exchanger is configured to generate a pressure drop in the first circuit of at least two bars. Such a configuration makes it possible to lower the temperature of the cooling fluid as it passes through the first circuit of the second heat exchanger. This maintains a good level of thermal performance in the operating mode called "cooling". Preferably, the first circuit of the second heat exchanger has a volume less than or equal to 7. 5 10-5 m3. Thus, an advantage of the present invention lies in the ability to limit the circulating coolant mass in the air conditioning loop, while maintaining a high level of performance, in the operating mode called "cooling" as in the operating mode says "heating". 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 presentation of its realization and, where appropriate, contribute to its definition, in which: - Figure 1 is a schematic view of a heating, ventilation and / or according to the present invention, in a mode of operation called "heating", - Figure 2 is a schematic view of the heating, ventilation and / or air conditioning system of Figure 1, in a mode of operation called "cooling" FIG. 3 is a Mollier diagram illustrating the thermodynamic cycle operated by the present invention in the operating mode called " Figure 4 is a diagrammatic view of an exemplary embodiment of a means for fixing the refrigerant capacity in the heating, ventilation and / or air conditioning system according to the present invention, and FIG. is a schematic view of another embodiment of the means for fixing the refrigerant capacity in the heating, ventilation and / or air conditioning system according to the present invention. It should be noted that, in the figures, the structural and / or functional elements 30 common to the various embodiments may have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional and material properties. According to the present invention, the terms "downstream" and "upstream" describe the position of one component relative to another, according to the refrigerant circulation direction in an air conditioning loop according to the present invention or in the direction of circulation. of coolant in a coolant circuit. 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 coolant passage or heat transfer fluid. FIGS. 1 and 2 are schematic views of a heating, ventilation and / or air-conditioning installation 1 of a passenger compartment of a motor vehicle according to the present invention, respectively, in a so-called "heating" mode of operation and in a operation called "cooling". The heating, ventilation and / or air conditioning installation 1 comprises a heating, ventilation and / or air conditioning system 2, intended to modify the aerothermal parameters of the passenger compartment of the vehicle. Such a modification of the aerothermal parameters is obtained from the diffusion of at least one pulsed interior air flow 3 inside the passenger compartment. For this purpose, the heating, ventilation and / or air conditioning system 2 comprises a housing 4, preferably made of plastic, housing a blower 5, or motor-fan unit 5, intended to circulate the interior air flow 3 from at least one air intake opening 6 to at least one air diffusion mouth 7 arranged in the housing 4. Such a heating, ventilation and / or air conditioning system 2 is, for example, housed under a dashboard of the vehicle and channels the circulation of the interior air flow 3. The heating, ventilation and / or air-conditioning installation 1 also comprises an air-conditioning loop 8 inside which circulates a refrigerant fluid, capable of supplying or removing calories, in order to allow the heat or the cooling of the flow of indoor air 3. The heating, ventilation and / or air conditioning system 1 also comprises at least one first heat transfer fluid circuit 25 and / or at least one second heat transfer fluid circuit 36. In the case where the cooling fluid provides calories to the first heat transfer fluid circuit 25 and / or the second heat transfer fluid circuit 36, it is considered that the heating, ventilation and / or air conditioning system 1 operates in the operating mode. says "heating". In the case where the refrigerant captures or takes heat from the first heat transfer fluid circuit 25, it is considered that the heating, ventilation and / or air conditioning system 1 operates in the so-called "cooling" mode of operation. To do this, the air conditioning loop 8 comprises a plurality of heat exchangers between the refrigerant and, on the one hand, a flow of air, and, on the other hand, the coolant, for example water added with glycol, circulating in one or more separate heat transfer fluid circuits, in particular the first heat transfer fluid circuit 25 and the second heat transfer fluid circuit 36. Preferably, the coolant is of the type of a super-critical fluid, such as carbon dioxide, also known as R744. It can also be a subcritical fluid, such as a hydrofluorocarbon, in particular the refrigerant known under the name R134a, or a coolant with low environmental pollution, particularly the refrigerant known under the name R1234yf. The air conditioning loop 8 comprises a compressor 9, able to compress the refrigerant in the gaseous state. The air conditioning loop 8 also comprises a first heat exchanger 10, in particular a gas cooler 10 or a condenser 10, the function of which is to ensure a heat exchange with a view to directly or indirectly influencing the temperature of the air flow. interior 3, intended to be broadcast in the passenger compartment. According to the example illustrated in FIG. 1, the heating, ventilation and / or air-conditioning system 1 also comprises the second heat-transfer fluid circuit 36, through which a heat transfer fluid, similar to or distinct from the heat transfer fluid circulating in the first cooling circuit, passes. heat transfer fluid 25. The function of the second heat transfer fluid circuit 36 is, in particular, to perform all or part of the heating function of the indoor air flow 3 in the so-called "heating" operating mode. The first heat exchanger 10 makes it possible to ensure a heat exchange between the refrigerant and the coolant circulating in the second heat transfer fluid circuit 36. Preferably, the first heat exchanger 10 is installed directly downstream of the compressor 9, according to the direction of circulation of the refrigerant in the air conditioning loop 8. In such an arrangement, the first heat exchanger 10 is a heat exchanger of the "coolant / heat transfer fluid" type. The second heat transfer fluid circuit 36 also comprises a second secondary heat exchanger 38. The function of the second secondary heat exchanger 38 is to ensure a heat exchange between the inner air flow 3 and the heat transfer medium secondary heat exchanger 38 circulating in the second coolant circuit 36. In such an arrangement, the second secondary heat exchanger 38 is a heat exchanger of the "coolant / air" type. Advantageously, the second secondary heat exchanger 38 is arranged in the housing 4 of the heating, ventilation and / or air conditioning system 1, and is traversed by the interior air flow 3. The coolant circulating in the second coolant circuit 36 is set in motion by a pump 39, said second pump 39, advantageously driven by an electric motor. According to a variant of the heating, ventilation and / or air conditioning system 1 not shown, the first heat exchanger 10 carries out a direct heat exchange between the refrigerant and the internal air flow 3, the first heat exchanger 10 comprising a bundle of tubes in which the cooling fluid circulates and outside of which circulates the internal air flow 3. In such an arrangement, the first heat exchanger 10 is a heat exchanger of the "refrigerant / air" type and is advantageously arranged in the casing 4 of the heating, ventilation and / or air conditioning system 1, and is traversed by the interior air flow 3. The air-conditioning loop 8, as shown in FIGS. 1 and 2, also comprises at least one first switching means 11, in particular a first four-way valve 11, and at least one second switching means 12, in particular one second four-way valve 12, allowing the heating, ventilation and / or air conditioning system 1 to operate according to various operating modes, in particular at least in the so-called "cooling" mode of operation and in the so-called operating mode " heater". To do this, the first switching means 11 and the second switching means 12 are connected to each other in order to define four circulation branches in each of which the refrigerant fluid is able to circulate. Preferably, with respect to the compressor 9 and in the direction of circulation of the refrigerant in the air conditioning loop 8, the second switching means 12 is disposed downstream of the first switching means 11. Thus arranged, the air conditioning loop 8 comprises a first circulation branch I, a second circulation branch II, a third circulation branch III and a fourth circulation branch IV, respectively arranged between the first switching means 11 and the second means switching 12. According to the present invention, the first branch of circulation I of the air conditioning loop 8 comprises a first heat exchanger 13, or external heat exchanger 13. Advantageously, the external heat exchanger 13 is located at a front face of the vehicle to be traversed by an outside air flow 14, intended not to be diffused into the passenger compartment of the vehicle. Preferably, the refrigerant circulates in the external heat exchanger 13, while the outside air flow 14 is set in motion by at least one motor-fan unit 35, for example two motor-fan units 35. Thus, in the so-called "cooling" mode of operation, the cooling fluid is cooled by the outside air flow 14 and, in the so-called "heating" operating mode, the cooling fluid is heated by the outside air flow 14 . The air conditioning loop 8 also includes an internal heat exchanger 17. The internal heat exchanger 17 comprises a first portion 32 and a second portion 33 independent and respectively traversed by the coolant at different states. More specifically, the internal heat exchanger 17 is able to achieve a heat exchange between a high pressure portion of the air conditioning loop 8 located between the compressor 9 and a first expansion member 18, and a low pressure portion of the air conditioning loop 8 located between the first expansion member 18 and the compressor 9. Preferably, the air conditioning loop 8 comprises the first expansion member 18 and a second expansion member 23. Advantageously, in the operating mode called "heating", the first expansion member 18 is active, the second expansion member 23 being preferably inactive. In the so-called "cooling" mode of operation, the second expansion member 23 is active, the first expansion member 18 being preferably inactive. The term "active" defines the configuration of the relaxation member in question in which an expansion of the refrigerant is ensured. Furthermore, the term "inactive" defines the configuration of the relaxation member in question in which no relaxation of the coolant is ensured. Preferably, the internal heat exchanger 17 is configured to achieve a heat exchange performance between the first portion 32 and the second portion 33 greater than 80%, especially greater than 87%, in particular greater than 95%. According to the present invention, the second circulation branch II of the air conditioning loop 8 comprises the first portion 32 of the internal heat exchanger 17 and the first expansion member 18. Preferably, the first portion 32 of the internal heat exchanger 17 is arranged upstream of the first expansion member 18. According to the present invention, the third circulation branch III of the air conditioning loop 8 comprises the second portion 33 of the internal heat exchanger 17, the compressor 9 and the first heat exchanger 10. Preferably, the second portion 33 of the internal heat exchanger 17 is arranged upstream of the compressor 9. In addition, the compressor 9 is arranged upstream of the first heat exchanger 10. The first heat exchanger 10 is intended to directly or indirectly heat the interior air flow 3 adapted to be diffused in the passenger compartment of the vehicle. Finally, according to the present invention, the fourth circulation branch IV of the air conditioning loop 8 comprises the second expansion member 23 and a second heat exchanger 24 whose function is to provide a heat exchange to influence directly or indirectly the temperature of the interior air flow 3, intended to be distributed in the passenger compartment. Preferably, the second relaxation member 23 is arranged upstream of the second heat exchanger 24. The second heat exchanger 24 makes it possible to ensure a heat exchange between the refrigerant and the coolant circulating in the first heat transfer fluid circuit 25. In such an arrangement, the second heat exchanger 24 is a heat exchanger of the "coolant / heat transfer fluid" type. Advantageously, the second heat exchanger 24 is arranged in the housing 4 of the heating, ventilation and / or air conditioning system 1, and is traversed by the interior air flow 3. According to an exemplary embodiment, the first heat transfer fluid circuit 25 is distinct from the second heat transfer fluid circuit 36, in that the respective heat transfer fluids do not mix. As an exemplary embodiment, the second heat exchanger 24 is installed, in the air conditioning loop 8, downstream of the first heat exchanger 10, in the direction of circulation of the refrigerant in the third branch of circulation III of the air conditioning loop 8 and the fourth branch of circulation IV of the air conditioning loop 8. In addition, preferably, the fourth circulation branch IV of the air conditioning loop 8 also comprises a storage device 34 for defining a refrigerant reservoir flowing in the air conditioning loop 8. Preferably, the storage device 34 is arranged downstream of the second heat exchanger 24. According to an exemplary embodiment, the refrigerant storage device 34 is an accumulator constituting a reserve of coolant in the liquid state. According to the present invention, the second heat exchanger 24 comprises a first circuit 40 and a second circuit 41, respectively traversed by the refrigerant circulating in the air conditioning loop 8 and by the coolant circulating in the first heat transfer fluid circuit 25. By way of example, the first circuit 40 and the second circuit 41 of the second heat exchanger 24 are delimited by tubes, preferably made by plates joined to each other, in which a plurality of fluid circulation channels is formed. refrigerant and heat transfer fluid. One part of the plurality of circulation channels forms the first circuit 40 and the other part of the plurality of circulation channels forms the second circuit 41, the circulation channels forming the first circuit 40 being alternated with the circulation channels forming the second circuit 41. Thus, the first circuit 40 thermally exchanges with the second circuit 41 of the second heat exchanger 24. According to an advantageous embodiment of the present invention, the heating, ventilation and / or air conditioning installation 1 is organized so that the circulation of the refrigerant in the first circuit 40 of the second heat exchanger 24 is co-current with the circulation of the fluid. coolant in the second circuit 41 of the second heat exchanger 24. The term "co-current" means that the refrigerant and the coolant circulate in an identical direction through the first circuit 40 of the second heat exchanger 24 and the second circuit 41 of the second heat exchanger 24. According to the present invention, the air conditioning loop 8 comprises a means for fixing the refrigerant fluid titer, adapted to be configured so that the refrigerant titer is less than 80% at the outlet of the first circuit 40 of the second heat exchanger 24, when the refrigerating fluid captures heat transfer medium calories through the second heat exchanger 24, that is to say when the heating, ventilation and / or air conditioning system 1 is used in the operating mode said " cooling". The title corresponds to the proportion by mass taken by the cooling fluid in the gaseous state in the mixing zone. The title therefore corresponds to the ratio of the mass of the cooling fluid in the gaseous state to the total mass of the refrigerant. With reference to FIG. 5, the title of the refrigerant at a given point, for example at a point G, is defined in relation to the enthalpy h, of the point under consideration, of the saturated vapor enthalpy h 'and of the enthalpy of liquid saturating son, at the pressure of the point considered. Thus, the title of the refrigerant at a given point is determined by the relation: ## EQU1 ## For example, at point G, the title of the refrigerant is about 0.75, or 75%. The means for fixing the refrigerant capacity may in particular take two embodiments which will be detailed with reference to FIGS. 4 and 5. The second heat exchanger 24 is configured to generate a pressure drop in the first circuit 40. Such a pressure drop is, for example, in the case of carbon dioxide, at least two bars, especially for a refrigerant flow rate of 150 kg / h and an evaporation temperature of 0 ° C., when the pressure of the refrigerant at the outlet of the first circuit 40 is equal to 35 bars. Such a pressure drop is thus operated on the refrigerant side. According to an exemplary embodiment, such a pressure drop is obtained by a volume of the first circuit 40 of the second heat exchanger 24, advantageously less than or equal to 7. 5 10-5 m3. The components of the air conditioning loop 8 described above are connected to each other via tubes, pipes or the like able to channel the refrigerant between the various components of the air conditioning loop 8. The first heat transfer fluid circuit 25 comprises the second heat exchanger 24, a first secondary heat exchanger 28 and a pump 29, called the first pump 29, intended to circulate the heat transfer fluid in the first heat transfer fluid circuit 25. The first secondary heat exchanger 28 is arranged to ensure a heat exchange between the coolant of the first coolant circuit 25 and the interior air flow 3 flowing in the housing 4 of the heating, ventilation and / or air conditioning system. 1. According to an exemplary embodiment, the first secondary heat exchanger 28 is a heat exchanger comprising a bundle of tubes in which circulates the heat transfer fluid of the first coolant circuit 25 and outside of which circulates the interior air flow 3 . The first secondary heat exchanger 28 is arranged in the housing 4 of the heating, ventilation and / or air conditioning system 1 in order to be traversed by the interior air flow 3. Preferably, the first secondary heat exchanger 28 is arranged upstream of the second secondary heat exchanger 38, in the direction of circulation of the interior air flow 3 in the housing 4 of the heating, ventilation and / or air conditioning system 1 . The housing 4 of the heating, ventilation and / or air-conditioning system 1 comprises at least one mixing flap 30 installed between the first secondary heat exchanger 28 and the second secondary heat exchanger 38 and capable of assuming a first position in which the mixing flap 30 constrains the interior air flow 3 through the second secondary heat exchanger 38, and a second position in which the mixing flap 30 prohibits the passage of the interior air flow 3 in the second secondary heat exchanger 38 and constrains the interior air flow 3 to bypass the second secondary heat exchanger 38. The mixing flap 30 is also able to take any intermediate positions between the first position and the second position in order to ensure a proportionate mixing of the interior air flow 3 having passed through the second secondary heat exchanger 38 and the flow of air. indoor air 3 having bypassed the second secondary heat exchanger 38. FIG. 1 shows the heating, ventilation and / or air-conditioning system 1 in the so-called "heating" operating mode which makes it possible to provide a heating function for the interior air flow 3 intended to be diffused in the passenger compartment of the vehicle . Such a configuration is, in particular, used during low temperatures, for example in winter. In the so-called "heating" mode of operation, the air conditioning loop 8 is configured so that the refrigerant is compressed and circulated by the compressor 9, then passes through the first heat exchanger 10, in which the refrigerant gives way. heat transfer fluid circulating in the second coolant circuit 36. In the so-called "heating" operating mode, the first switching means 11 is configured to put in communication: the second circulation branch II with the first circulation branch I, and the third circulation branch III with the fourth branch of circulation IV. Moreover, in the so-called "heating" operating mode, the second switching means 12 is configured to put in communication: the first circulation branch I with the third circulation branch III, and the fourth circulation IV with the second branch of circulation II. As a result, in such an arrangement, the refrigerant passes through the first switching means 11 and passes into the second expansion member 23 without undergoing pressure reduction. To do this, advantageously, the second expansion member 23 is fully open and passes the refrigerant without restriction. Alternatively, according to an embodiment not shown, it can be provided a bypass line comprising a control valve (not shown) allowing the refrigerant to bypass the second expansion member 23. The refrigerant fluid, at high pressure and at high temperature, then passes through the first circuit 40 of the second heat exchanger 24, the calories present in the refrigerant being transferred to the coolant circulating in the first heat transfer fluid circuit 25 by heat exchange. between the first circuit 40 and the second circuit 41 of the second heat exchanger 24. After passing through the second heat exchanger 24, the refrigerant enters the storage device 34. According to an alternative embodiment of the present invention, the means for fixing the cooling fluid titer is integrated with the storage device 34. The refrigerant then flows into the second switching means 12. As a result, the cooling fluid enters the internal heat exchanger 17, in particular the first portion 32 of the internal heat exchanger 17 forming a high pressure internal circuit of the internal heat exchanger 17, in which the fluid circulates. high pressure and high temperature refrigerant. According to another embodiment of the present invention, the means for fixing the cooling fluid titer is integrated with the internal heat exchanger 17, the second portion 33 of the internal heat exchanger 17 being formed by two separate sub-circuits. by the storage device 34. After the internal heat exchanger 17, the refrigerant passes through the first expansion member 18. The first expansion member 18 ensures a relaxation of the refrigerant fluid, generating a lowering of the pressure of the refrigerant. As a result, the refrigerant flows through the first switching means 11 and to the first heat exchanger 13. In the first heat exchanger 13, the refrigerant, expanded exchange with the flow of outside air 14, resulting in a temperature rise of the refrigerant. In the so-called "heating" operating mode, the outdoor exchanger 13 behaves like an evaporator. As a result, the coolant passes through the second switching means 12 and enters the second portion 33 of the internal heat exchanger 17, forming a low pressure internal circuit of the internal heat exchanger 17, in which the fluid circulates. refrigerant at low pressure and low temperature. As the air-conditioning loop 8 is a closed circuit, the refrigerant terminates its cycle on reaching the inlet of the compressor 9. In the so-called "heating" operating mode, the first heat transfer fluid circuit 25 is active for heating the passenger compartment of the vehicle. In addition or alternatively, the second heat transfer fluid circuit 36 is active to ensure the complementary heating of the passenger compartment of the vehicle. For this purpose, the coolant of the first coolant circuit 25 is circulated by the first pump 29 and the calories present in the coolant coolant are then transferred to the heat transfer fluid of the first coolant circuit 25 by means of the exchange. heat produced in the second heat exchanger 24. The first pump 29 being activated, the coolant transfers the calories to the first secondary heat exchanger 28, which is then transferred to the interior air stream 3. Preferably, the upstream arrangement of the first secondary heat exchanger 28 with respect to the second secondary heat exchanger 38, the first secondary heat exchanger 28, coupled to the second heat exchanger 24, performs a preheating function of the indoor air flow. 3, a set temperature of the inner air flow 3 that can be reached by heat exchange between the preheated inner air flow 3 and the second secondary heat exchanger 38. FIG. 2 shows the heating, ventilation and / or air-conditioning system 1 in the so-called "cooling" operating mode that makes it possible to provide a cooling function for the interior air flow 3 intended to be diffused in the passenger compartment of the vehicle . Such a configuration is, in particular, used at high temperatures, for example in summer. In the operating mode called "cooling", the second heat transfer fluid circuit 36 is not active, the second pump 39 being stopped. In the operating mode called "cooling", the air conditioning loop 8 is configured so that the refrigerant is compressed and circulated by the compressor 9, then passes through the first heat exchanger 10 without heat exchange with the heat transfer fluid of the second coolant circuit 36. Alternatively, such an absence of heat exchange can also be achieved by means of a bypass line (not shown) of the first heat exchanger 10 of the refrigerant side. In the so-called "cooling" mode of operation, the first switching means 11 is configured to put in communication: the third circulation branch III with the first circulation branch I, and the second circulation branch with the second circulation branch. fourth branch of circulation IV. Furthermore, in the so-called "cooling" mode of operation, the second switching means 12 is configured to put in communication: - the first branch of circulation I with the second branch of circulation II, and - the fourth branch of circulation IV with the third branch of circulation III. In such an arrangement, the refrigerant passes through the first switching means 11. As a result, the refrigerant fluid, at high pressure and at high temperature, passes through the first heat exchanger 13 in which the cooling fluid condenses, the refrigerant then being cooled by the outside air flow 14. The refrigerant then flows into the second switching means 12. As a result, the coolant enters the first portion 32 of the internal heat exchanger 17, forming a high pressure internal circuit of the internal heat exchanger 17, in which the high-pressure refrigerant circulates and at high temperature. As a result, the refrigerant fluid passes through the first expansion member 18 without undergoing a lowering of pressure. To do this, advantageously, the first expansion member 18 is fully open and lets the refrigerant fluid without restriction. Alternatively, according to an embodiment not shown, it can be provided a bypass line comprising a control valve (not shown) allowing the refrigerant to bypass the first expansion member 18. The refrigerant then passes into the first switching means 11. As a result, the coolant enters the second expansion member 23. The second expansion member 23 serves to relax the refrigerant fluid, generating a lowering of the refrigerant pressure. As a result, the coolant, at low pressure, passes through the second heat exchanger 24. After having traversed the second heat exchanger 24, the refrigerant passes through the storage device 34, in which the coolant in the liquid state can be stored. At the outlet of the storage device 34, the refrigerant passes through the second switching means 12 before passing through the second portion 33 of the internal heat exchanger 17, forming a low pressure internal circuit of the internal heat exchanger 17, in which circulates the refrigerant fluid at low pressure and at low temperature. As the air-conditioning loop 8 is a closed circuit, the refrigerant terminates its cycle on reaching the inlet of the compressor 9. In the operating mode called "cooling", the first heat transfer fluid circuit 25 is active to ensure cooling of the passenger compartment of the vehicle. For this purpose, the coolant of the first heat transfer fluid circuit 25 is circulated by the first pump 29 and the calories present in the coolant are then transferred to the heat transfer fluid in the first heat transfer fluid circuit 25 by means of the heat transfer fluid. heat exchange carried out in the second heat exchanger 24. The first pump 29 being activated, the coolant transfers the calories to the first heat exchanger 28 in which they are transferred to the inner air stream 3. According to an advantageous embodiment of the present invention, the heating, ventilation and / or air conditioning installation 1 is organized so that the circulation of the refrigerant in the first circuit 40 of the second heat exchanger 24 is co-current with the circulation of the fluid. coolant in the second circuit 41 of the second heat exchanger 24. The term "co-current" means that the refrigerant and the coolant circulate in an identical direction through the first circuit 40 of the second heat exchanger 24 and the second circuit 41 of the second heat exchanger 24. The arrangement of the co-current circulation in the second heat exchanger 24 makes it possible to release the coolant from the second circuit 41 of the second heat exchanger 24 to a temperature close to, or even lower than, that of the refrigerant measured at entry of the first circuit 40 of the second heat exchanger 24, since the vaporization of the refrigerant during the passage of the first volume 40 of the second heat exchanger 24 causes a lowering of the temperature. The means for fixing the refrigerant fluid title prevents the refrigerating fluid from totally vaporizing at the heart of the first circuit 40 of the second heat exchanger 24. Thus, the second heat exchanger 24 is "flooded" by the refrigerant fluid, since a part of the refrigerant fluid in the liquid state is found at the outlet of the first portion 40 of the second heat exchanger 24. Figure 3 is a Mollier diagram illustrating the thermodynamic cycle operated by the present invention in the operating mode called "cooling", the air conditioning loop 8 being traversed by carbon dioxide. It presents the steps of the thermodynamic cycle operating in the air conditioning loop 8 when it is in the operating mode mode called "cooling", as shown in FIG. The thermodynamic cycle starts at the input of the compressor 9, illustrated by the point A. The compressor 9 raises the pressure and the temperature of the refrigerant until reaching point B. The coolant is then cooled through the outer heat exchanger 13 to reach the point C. As a result, the coolant undergoes a heat exchange inside the first portion 32 of the internal heat exchanger 17. Such a heat exchange is materialized by the segment between the point C and a point E corresponding to the outlet of the first portion 32 of the internal heat exchanger 17. More particularly, Figure 3 shows a point D, located between point C and point E. The point D corresponds to a particular point in relation to the second embodiment of the means for fixing the refrigerant capacity, as illustrated in FIG. 5, providing that the means for fixing the refrigerant titre take the form of the first portion 33 of the internal heat exchanger 17 comprising two sub-circuits separated by the storage device 34. The point D therefore corresponds to the state of the refrigerant at the inlet of the storage device 34, as arranged according to the second embodiment of the means for fixing the refrigerant capacity. The refrigerant is then expanded in the second expansion member 23 to reach the point F corresponding to the state of the refrigerant at the outlet of the second expansion member 23 after the expansion of the refrigerant. As a result, the refrigerant passes through the first portion 40 of the second heat exchanger 24 to reach the point G. The thermodynamic cycle ends to return to the point A, the portion between the point G and the point A corresponding to a circulation of the refrigerant in the second portion 33 of the internal heat exchanger 17. It can be seen on the Mollier diagram according to FIG. 3 that the point G is placed on a particular isotitre, for example 0.75. Such a point G is obtained by means of fixing the title of the refrigerant whose purpose is to impose a titre of less than 80% at the output of the first circuit 40 of the second heat exchanger 24. This means that the coolant is not completely vaporized inside the second heat exchanger 24. The additional vaporization is then carried out in the second portion 33 of the internal heat exchanger 17, this complement of vaporization corresponding to the phase of the thermodynamic cycle between the points G and a point H corresponding to the output of the corresponding to the outlet of the first portion 32 of the internal heat exchanger 17. It is therefore understood that part of the internal heat exchanger 17 functions as an evaporator, this being made possible in particular by the use of an internal heat exchanger 17 whose thermal efficiency is at least equal to 80%, advantageously at least 87%, especially equal to 95%. This organization makes it possible to reduce the internal volume of the second heat exchanger 24, side of the cooling fluid, without impairing the thermal performance of the second heat exchanger 24, especially in the operating mode called "cooling", but also in the operating mode. of operation said "heating". FIG. 4 is a schematic view of an exemplary embodiment of a means for fixing the refrigerant capacity in the heating, ventilation and / or air conditioning system 1 according to a first embodiment, in which the fixing means the title of the refrigerant is placed at the outlet of the first circuit 40 of the second heat exchanger 24. According to the first embodiment, the means for fixing the title of the refrigerant fluid is an integral part of the storage device 34. The means for fixing the refrigerant fluid's titer is then configured so that coolant in the liquid state leaves the storage device 34, in a determined proportion. For this purpose, the storage device 34 comprises an inlet pipe 43 channeling the refrigerant fluid from the first circuit 40 of the second heat exchanger 24. At this stage, the refrigerant fluid is in a two-phase state, comprising, for example, 80% of refrigerant fluid in the gaseous state and 20% of refrigerant in the liquid state. The storage device 34 also comprises a chamber 44 at the bottom of which the coolant in the liquid state accumulates. The storage device 34 also comprises an outlet pipe 45, advantageously having a "U" shape, so as to predominantly take the cooling fluid in the gaseous state. Nevertheless, the outlet duct 45 comprises a sensing device 42 forming an exemplary embodiment of the means for fixing the title of the refrigerant fluid. The capture device 42 takes, for example, the shape of an opening 46 formed in the outlet pipe 45, in a zone of the outlet pipe 45 immersed in the coolant in the liquid state. Preferably, the opening 46 is, for example, located at the low point of the bend formed by the outlet pipe 45. According to the present invention, the opening 46 has a coolant passage section in the liquid state, for example, between 1 mm 2 and 6 mm 2. According to the first embodiment of the title fixing means, part of the second portion 33 of the internal heat exchanger 17 is dedicated to the implementation of the end of the evaporation, so as to bring the title of the refrigerant from 80% to 100%, corresponding to a totally gaseous state. FIG. 5 is a schematic view of a second exemplary embodiment of the means for fixing the refrigerant capacity in the heating, ventilation and / or air conditioning system 1 according to the present invention in which the means for fixing the fluid's title refrigerant is disposed at the outlet of the first circuit 40 of the second heat exchanger 24. According to the second exemplary embodiment, the means for fixing the refrigerant fluid titer is integrated with the internal heat exchanger 17, in particular in the second portion 33 subjected to the refrigerant fluid at low pressure and low temperature. Such an internal heat exchanger 17 thus comprises the first portion 32 traversed by the refrigerant fluid and arranged in the high pressure portion of the air conditioning loop 8, and the second portion 33 traversed by the refrigerant fluid and arranged in the low pressure portion of the air conditioning loop 8. According to the second exemplary embodiment of the means for fixing the title of the refrigerant, the second portion 33 of the internal heat exchanger 17 is formed by two sub-portions separated by the storage device 34. Thus, a first sub-portion 47 receives the refrigerant from the first circuit 40 of the second heat exchanger 24, which is also traversed by the coolant of the first coolant circuit 25. The first sub-portion 47 is connected to the storage device 34, connected to a second sub-portion 48 of the second portion 33 of the internal heat exchanger 17. The first sub-portion 47 thus carries out the complementary evaporation between a titre of 80% and a titre of 100%, by heat exchange with the first portion 32 of the internal heat exchanger 17. According to an alternative embodiment, the internal heat exchanger 17, the storage device 34 and the heat exchanger 24 are integral with each other so as to form a unitary module 100, forming a single module 100 facilitating the integration of such a module in the motor vehicle. Such a unitary module 100 is characterized in that the number of coolant inlet and outlet is reduced. In a particular example, the unitary module 100 comprises four passages 49 through which the refrigerant enters or leaves the unitary module 100. Two passages 49 are connected to the first portion 32 of the internal heat exchanger 17, a third passage 49 is connected to the input of the first circuit 40 of the second heat exchanger 24 and the fourth passage 49 communicates with the output of the second sub-portion 48 of the second portion 33 of the internal heat exchanger 17. Alternatively or additionally, the unitary module 100 may further comprise a single heat transfer fluid inlet 50 and a single heat transfer fluid outlet 51, these being arranged so that the circulation of the cooling fluid and the circulation of the heat transfer fluid are co- current, that is to say that the coolant and the heat transfer fluid circulate in the same direction of circulation inside the second heat exchanger 24. 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 considered by those skilled in the art in the context of the present invention and in particular any combination of the different modes of operation described above, which can be taken separately or in combination. 2 9902 64 Claims 1. Heating, ventilation and / or air-conditioning installation (1) comprising an air-conditioning loop (8), inside which a cooling fluid circulates, a first heat-transfer fluid circuit (25), inside which circulates a heat transfer fluid, the air conditioning loop (8) and the first coolant circuit (25) being interconnected via at least one heat exchanger (24), or second heat exchanger (24), comprising a first circuit (40), traversed by the refrigerant fluid and connected to the air conditioning loop (8), and a second circuit (41), traversed by the coolant and connected to the first coolant circuit (25), so as to to ensure a heat exchange between the refrigerant and the heat transfer fluid, characterized in that the circulation of the refrigerant in the first circuit (40) of the second heat exchanger (24) is co-current with the circulation of the fluid ca the carrier in the second circuit (41) of the second heat exchanger (24). 20

2. Installation according to claim 1, wherein the air conditioning loop (8) comprises means for fixing the title of the refrigerant.

3. Installation according to claim 1 or 2, wherein the air conditioning loop (8) comprises at least one compressor (9), a first expansion member (18), a refrigerant storage device (34) and at least one less an internal heat exchanger (17), able to achieve a heat exchange between a high pressure portion of the air conditioning loop (8), located between the compressor (9) and the first expansion member (18), and a lower part air conditioning loop pressure (8), located between the first expansion member 30 (18) and the compressor (9).

4. Installation according to claims 2 and 3, wherein the means for fixing the title of the refrigerant is integrated in the storage device (34).

5. Installation according to claim 4, wherein the means for fixing the title of the refrigerant is formed by a sensor (42) of the coolant in the liquid state contained in the storage device (34).

6. Installation according to claims 2 and 3, wherein the means of fixing the title of the refrigerant is integrated with the internal heat exchanger (17) comprising a first portion (32) traversed by the refrigerant and arranged in the part high pressure of the air conditioning loop (8), and a second portion (33) traversed by the refrigerant fluid and arranged in the low pressure portion of the air conditioning loop (8).

7. Installation according to claim 6, wherein the second portion (33) of the internal heat exchanger (17) is formed by a first sub-portion (47) and a second sub-portion (48), separated by the storage device (34).

8. Installation according to claim 7, wherein the internal heat exchanger (17), the storage device (34) and the second heat exchanger (24) are integral with each other so as to form a unitary module ( 100).

9. Installation according to claim 8, wherein the unitary module (100) comprises at most four passages (49) through which the coolant enters or leaves the unitary module (100).

10. Installation according to claim 8 or 9, wherein the unitary module (100) comprises a single inlet (50) of coolant and a single outlet (51) of heat transfer fluid.

11. Installation according to any one of the preceding claims, whereinthe coolant is carbon dioxide.

12. Installation according to any one of the preceding claims, wherein the second heat exchanger (24) is configured to generate a pressure drop in the first circuit (40) of at least two bars.

13. Installation according to any one of the preceding claims, wherein the first circuit (40) of the second heat exchanger (24) has a volume less than or equal to 7.5 10-5 m3.10.