WO2018002464A1

WO2018002464A1 - Air conditioning system and method for a compartment, in particular a motor vehicle passenger compartment

Info

Publication number: WO2018002464A1
Application number: PCT/FR2017/051423
Authority: WO
Inventors: Mohamed Yahia; Bertrand Nicolas; Laetitia Clemaron; Régine Haller; Jean-Luc Thuez; Jin-ming LIU
Original assignee: Valeo Systemes Thermiques
Priority date: 2016-06-30
Filing date: 2017-06-06
Publication date: 2018-01-04
Also published as: FR3053447B1; FR3053447A1

Abstract

The invention concerns an air conditioning system for a compartment, said system comprising: - an external heat exchanger (21) for carrying out an exchange of heat between a refrigerant and a flow of air (E) circulating outside the compartment, - first (6) and second (27) internal heat exchangers for carrying out an exchange of heat involving the refrigerant; said system being configured to function in an air conditioning mode in which it takes heat out of a flow of air (I) that is to be blown into the compartment, using said first and second internal heat exchangers (6, 27), and discharges the heat outside the compartment using the external heat exchanger (21).

Description

SYSTEM AND METHOD FOR AIR CONDITIONING FOR A COMPARTMENT, IN PARTICULAR A VEHICLE HABITACLE

The invention relates to a system and a method for conditioning a flow of air entering a compartment, for example a vehicle interior, including a system for ventilation, heating and / or air conditioning of the compartment.

Motor vehicles are commonly equipped with a ventilation system, heating and / or air conditioning to change the aerothermal parameters of the air contained inside the cabin of the vehicle. Such a modification is obtained from the delivery of a flow of air blown inside the passenger compartment. In the case of an electric or hybrid vehicle, whose propulsion is provided at least partially by an electric motor, such a system is necessarily adapted to the permanent absence (electric vehicle) or temporary (hybrid vehicle) hot source such as a thermal engine on this type of vehicles.

Such a system is expected to fulfill all or some of the following functions or modes:

- Cooling, also called air conditioning,

- Heater,

- Dehumidification, that is to say the cooling of the air drawn into the passenger compartment, whether in the cooling function or the heating function, so as to cause the condensation of part of the water vapor that it contains.

Such a system comprises in known manner an air conditioning unit usually housed under a dashboard of the vehicle.

The housing has a ventilation unit. He receives a flow of outside air and draws it for delivery inside the cockpit. Inside this housing are usually housed a first heat exchanger for cooling the air drawn to the passenger compartment of the vehicle and a second heat exchanger for heating the cabin. These different members are connected to each other and to another heat exchanger, said outside, located on the front of the vehicle to exchange heat with an outside air flow, a circuit of pipes in which a refrigerant circulates. This circuit further comprises a compressor, at least one expander capable of decompressing the fluid and means such as valves for differently orienting the fluid in the different pipes according to the mode of operation sought by the user.

This system can be used in cooling mode or heating mode. In cooling mode, the refrigerant is sent from the compressor to the external heat exchanger acting as a condenser where it is cooled by the outside air flow. Then, the refrigerant flows to a pressure reducer where it undergoes a lowering of its pressure before entering the first heat exchanger operating as an evaporator. The refrigerant passing through the evaporator is then heated by the flow of air entering the ventilation system, which is correlatively reflected by a cooling of this air flow in order to air condition the passenger compartment of the vehicle. The circuit being a closed loop, the refrigerant then returns to the compressor.

In heating mode, the refrigerant is sent from the compressor to the first and / or the second heat exchanger. At least one of these then behaves like condensers, in which the refrigerant is cooled by the air circulating in the ventilation system. This air is heated therefore in contact with the exchanger in question and thus brings calories to the passenger compartment of the vehicle. After passing through this exchanger, the refrigerant is expanded by a pressure regulator before reaching the external heat exchanger acting as an evaporator. It is then warmed by the outside air. The refrigerant then returns to the compressor.

However, in the known solutions, the operation in air conditioning mode is not optimal. An object of the present invention is to provide an air conditioning system which at least partially overcomes the aforementioned problems.

The invention relates in this sense to an air conditioning system for a compartment, said system comprising:

an external heat exchanger for exchanging heat between a refrigerant and a flow of air flowing outside the compartment,

first and second inner heat exchangers for performing heat exchange involving the refrigerant; said system being configured to operate in an air conditioning mode in which it draws heat from a flow of air to be blown into the compartment, using said first and second indoor heat exchangers and discharges it to the outside of the compartment using the outdoor heat exchanger.

Thanks to the invention, the two indoor heat exchangers are simultaneously operated, in cooling mode, to cool the flow of air flowing inside the compartment. The exchange surface is thus optimized, including in this mode, rather than leaving one of the two exchangers unused, as is the case in the systems of the state of the art.

Preferably, said system is configured to operate in the air conditioning mode to draw heat in the air flow to be blown into the compartment, optionally, using said first and / or second heat exchangers interiors.

According to various additional features of the invention, which may be taken together or separately:

said system comprises a main supply branch, said system being configured to circulate said high-pressure refrigerant towards at least one of said first and / or second indoor heat exchangers, preferably said first heat exchanger interior, in said main power branch, in said air conditioning mode,

said main power supply branch comprises a first expander,

said system comprises at least one return branch, said system being configured to circulate said low pressure refrigerant from at least one of said first and / or second indoor heat exchangers in said return branch in said air conditioning mode; ,

said system further comprises a first intermediate branch connecting said first and second internal heat exchangers, said first intermediate branch being configured to be traversed in a first direction by the refrigerant, in said air-conditioning mode, from said first indoor exchanger to said second indoor exchanger, said first intermediate branch comprises a regulator, said intermediate,

said intermediate expander is a sealed pressure regulator,

said first intermediate branch further comprises a non-return valve, called an intermediate anti-return valve, configured to prevent a circulation of the refrigerant in said first intermediate branch in a direction opposite to the first direction,

said system furthermore comprises a so-called link branch, said link branch being configured to be traversed in a first direction by the refrigerant, in said air-conditioning mode, from said second internal exchanger to the return branch,

said link branch comprises a so-called connection valve, permitting or not, optionally, a circulation of the refrigerant in said connecting branch,

said connecting branch furthermore comprises a non-return valve, called a connection non-return valve, configured to prohibit a circulation of the refrigerant in said connection branch in a direction opposite to the first direction,

said first intermediate branch, said second internal heat exchanger and said connecting branch are connected in series, in this order, in a direction of circulation of the refrigerant in the air-conditioning mode, so as to form a bypass path,

said branching path is mounted in parallel with said return branch,

said system is further configured to operate in a heat pump mode in which it draws heat from the air outside the compartment using the external heat exchanger and discharges it into a flow. air to be blown into the compartment using at least one of the indoor heat exchangers, in particular using the first and second indoor heat exchangers,

said system comprises a second intermediate branch connecting said second indoor heat exchanger and said main supply branch, said second intermediate branch being configured to be traversed in a first direction by the refrigerant, in said heat pump mode, from said second exchanger to said main power branch,

the first expander is located on said main supply branch, between said second intermediate branch and said first heat exchanger so as to be traversed by said fluid both in said air conditioning mode and in said mode heat pump,

said system comprises another secondary supply branch, said system being configured to circulate said high-pressure refrigerant towards at least one of said first and / or second indoor heat exchangers, preferably said second heat exchanger, internal heat, in said secondary supply branch, in said air conditioning mode and / or heat pump,

said system is configured so that the flow direction of the refrigerant in the first indoor air-conditioning heat exchanger is unchanged, at least in said air conditioning mode and said heat pump mode,

said system is configured to operate, optionally, in said heat pump mode, in said cooling mode and in an additional heat recovery mode, in which it draws heat from the air flow to be blown inside the compartment using the first indoor heat exchanger and rejects it in the flow of air to be blown inside the compartment using the second indoor heat exchanger, said refrigerant bypassing said outdoor heat exchanger.

The invention also relates to an air conditioning unit comprising a first and a second indoor heat exchanger for performing a heat exchange involving a refrigerant, said unit being configured to operate in an air-conditioning mode from which it draws from the heat in the air stream I to be blown into the compartment, using said first and second indoor heat exchangers. Said unit has, for example, the branches mentioned above. It is intended to be used, in particular, in the system already described.

The invention also relates to an air conditioning method using the conditioning system described above, especially in heat pump mode and / or air conditioning mode. Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below as an indication in relation to drawings in which:

Figure 1 is a schematic illustration of an air conditioning system according to the present invention, used in cooling mode, without dehumidification, according to a first variant of operation,

FIG. 2 shows FIG. 1 in cooling mode, without dehumidification, according to a second variant of operation,

FIG. 3 shows FIG. 1, in cooling mode, without dehumidification, according to a third variant of operation,

Figure 4 shows Figure 1 in cooling mode, with dehumidification, Figure 5 shows Figure 1 in heat pump mode, without dehumidification, Figure 6 shows Figure 1 in heat pump mode, with dehumidification, Figure 7 shows FIG. 1 in heat recovery mode,

FIG. 8 is a schematic illustration of a part of an air conditioning system according to the present invention,

FIG. 9 is a schematic illustration of a first variant, according to the invention, of the air-conditioning system of FIG. 1,

FIG. 10 is a schematic illustration of a second variant, according to the invention, of the air-conditioning system of FIG.

In these different figures, identical elements are identified by the same references.

As illustrated in the various figures, the invention relates to an air conditioning system for a compartment, in particular a cabin of a motor vehicle. Said system comprises a closed circuit inside which a refrigerant circulates. The refrigerant is for example a supercritical fluid such as carbon dioxide referenced R-744. The refrigerant is for example still a subcritical fluid such as a fluorinated refrigerant referenced R-134a, or non-fluorinated referenced 1234yf.

Said system comprises an external heat exchanger 21 for exchanging heat between the refrigerant and a flow of air E flowing outside the compartment. Said external heat exchanger 21 is intended to be located, by example, in the front of a motor vehicle. As will be detailed below, it is intended to operate reversibly, either as an evaporator or as a condenser / gas cooler. The system further includes a first 6 and a second 27 indoor heat exchanger for performing heat exchange involving the refrigerant. The first indoor heat exchanger 6 is configured to allow an exchange of heat between said refrigerant and a flow of air I to be blown, or pulsed, inside the passenger compartment. The second exchanger 27 is here also configured to allow a heat exchange between said refrigerant and said air flow I to be blown inside the passenger compartment. As will be detailed below, said first 6 and second 27 indoor heat exchangers 6 are intended to operate reversibly, either as an evaporator or as a condenser / gas cooler. Said indoor heat exchangers 6, 27 are located inside a housing 8, called air conditioning, allowing the flow of air I to be blown into the passenger compartment. Said first indoor heat exchanger 6 is located upstream with respect to the second heat exchanger 27 in the direction of circulation of said air flow I to be blown inside the passenger compartment. Said housing 8 may comprise bypass ducts of the at least one indoor heat exchanger 6, 27, not shown, in particular the second heat exchanger 27.

Alternatively, not illustrated, said second indoor heat exchanger may be configured to allow heat exchange with a heat transfer fluid circulating in a circulation loop of said heat transfer fluid, said heat transfer fluid circulation loop comprising an additional heat exchanger allowing a heat exchange between said heat transfer fluid and said air flow I intended to be blown into the passenger compartment. Said additional heat exchanger is positioned in the air conditioning case in place of the second indoor heat exchanger.

Said system further comprises here a heat exchanger 24, said internal, and said system comprises a branch 25, said high pressure, and a branch 26, said low pressure, intended to pass through said internal exchanger. Said internal exchanger 24 is configured to allow heat exchange between said refrigerant circulating in said low pressure branch 26 and the refrigerant flowing in said high pressure branch 25. The system further comprises a compressor 20 for carrying the high pressure refrigerant, an accumulator 18 for storing the refrigerant, or even to effect a phase separation, and a first expansion member 2 associated with the first indoor heat exchanger 6, a second expansion member 23 associated with the heat exchanger 21 outside, and a third expansion member, in particular an expander 400, said intermediate, whose role will be detailed below. Inside said expansion members 2, 23, 400, the refrigerant is relieved, if necessary. Said first expansion member, said second expansion member and / or said intermediate expansion valve may be sealed expansion valves and act as a first control valve to allow or prevent the passage of refrigerant. They will also be fully open and not operate any relaxation.

The refrigerant circuit has a particular architecture to offer different modes of operation, as described below. More particularly, the refrigerant circuit comprises a plurality of circulation lines 28, 29, 30, 31, 32, 33, 34 through which the refrigerant circulates or does not circulate in the open or closed position of control valves 102, 103 , 104, 105, 106 or non-return valves 301, 302, 303, 304, 305, 306, 307, 308 that the circulation lines 28, 29, 30, 31, 32, 33, 34 comprise. These circulation lines 28, 29, 30, 31, 32, 33, 34 are connected to each other via a connection point 17 and junction points referenced 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 211.

The refrigerant circuit comprises in particular a first circulation line 28 which successively comprises the compressor 20, a first junction point 201, a second control valve 102, a second junction point 202, the external heat exchanger 21, a third junction point 203, a first non-return valve 301 allowing the refrigerant to pass only from the third junction point 203 to a fourth junction point 204 of said first flow line 28. Then, the first flow line 28 successively includes the high pressure branch 25, a fifth junction 205, a second check valve 302 allowing the passage of the refrigerant only fifth junction point 205 to a sixth junction point 206 of said first line of circulation 28. Following said sixth junction point 206, the first circulation line 28 comprises successively the first expansion member 2, the first indoor heat exchanger 6, a seventh junction point 207 and a connection point 17. Then, the first circulation line 28 comprises successively a third control valve 103, an eighth 208 and a ninth 209 junction points, the accumulator 18 and the low pressure branch 26 of the internal exchanger 24 to return to the compressor 20.

The refrigerant circuit also comprises a second refrigerant circulation line 29 which extends between the first junction point 201 and the sixth junction point 206. The second circulation line 29 comprises successively, from the first junction point 201 to the sixth junction point 206, a fourth check valve 104, a third check valve 303, a tenth junction point 210, the second inside heat exchanger 27, an eleventh junction point 211 and a fourth check valve. return 304.

The refrigerant circuit also comprises a third refrigerant circulation line 30 which extends between the second junction point 202 and the ninth junction point 209 and which comprises a fifth control valve 105, or even a non-return valve. passing through the second junction point 202 to the ninth junction point 209. We will return below to the role of this third circulation line 30.

The refrigerant circuit also comprises a fourth circulation line 31 which extends between the connection point 17 and the fifth junction point 205 and which comprises a fifth non-return valve 305 allowing the passage of the refrigerant only from the point of contact. link 17 to the fifth junction point 205.

The refrigerant circuit also comprises a fifth circulation line 32 which extends between the third junction point 203 and the fourth junction point 204 and which comprises the second expansion member 23. Said refrigerant circuit also comprises a sixth circulation line 33 extending between the seventh 207 and the eleventh 211 junction points. Said sixth circulation line 33 comprises in this order from the seventh junction point 208 to the eleventh junction point 211 the intermediate expansion valve 400 and a non-return valve 306, called intermediate non-return valve, configured to prohibit a circulation of the fluid refrigerant in said sixth circulation line 33 of the eleventh junction point 211 to the seventh junction point 207. Said system also comprises a seventh circulation line 34, extending between the tenth 210 and the eighth 208 junction points. Said seventh circulation line 34 comprises in this order from the tenth junction point 210 to the eighth junction point 208 a control valve 106, called a connecting valve, and a non-return valve 307, called a link non-return valve. configured to prohibit refrigerant flow in said seventh circulation line from said eighth junction point 208 to said tenth junction point 210.

As mentioned above, the refrigerant circuit is able to operate in various modes. More particularly, the refrigerant circuit is able to operate at least:

in a first mode, called air conditioning mode, in which the flow of air I is cooled prior to a delivery of the latter inside the passenger compartment of the motor vehicle, in other words, a mode in which the system draws the heat on the flow of air to be blown inside the compartment, using the first 6 or even the second 27, internal heat exchangers, and the rejects in the flow of air flowing to the outside of the compartment, using the external heat exchanger 21,

in a second mode, called heat pump or heating mode, in which the air flow I is heated before it is delivered inside the passenger compartment of the motor vehicle, in other words, a mode in which the system takes heat to the air, using the external heat exchanger 21, and reject it in a flow of air to be blown inside the compartment, using said second 27, see said first 6, indoor exchangers,

- in a third mode, called heat recovery mode in which it takes from the heat on the air flow intended to be blown inside the compartment using the first indoor heat exchanger 6 and rejects in the same air flow using the second indoor heat exchanger 27 The first and second modes are each available in a sub-mode with or without dehumidification. The air conditioning sub-mode without dehumidification is also available in different variants. These different modes, sub-modes and variants are illustrated in Figures 1 to 7, as detailed below. According to the invention, said system is configured to operate, in at least one of the variants of the cooling mode without dehumidification (FIG. 2), by taking heat from the air flow I to be blown inside the compartment, by means of said first and second indoor heat exchangers 6, 27, and rejecting it outside the compartment with the aid of the external heat exchanger 21. In this way, the use of the indoor heat exchangers, using them simultaneously for the same purpose, namely in an evaporator for cooling the air flow I to be blown inside the compartment.

For this purpose, as illustrated in FIG. 8, said system comprises, for example, a so-called main power branch 500, said system being configured to circulate said refrigerant in said main supply branch 500 to said first heat exchanger. indoor heat 6, in said air conditioning mode, this in all of its sub-modes and variants of operation. In the embodiment of FIGS. 1 to 7, said supply branch corresponds to the part of the first circulation line 28 situated between the fifth junction point 205 and the first indoor heat exchanger 6. Said main power supply branch 500 thus comprises the first expander 2 upstream of which, said refrigerant is at high pressure and downstream from which it passes at low pressure before entering said first internal exchanger 6, in all or part of the operating variants of the sub-mode of air conditioning without dehumidification and in the air conditioning sub-mode with dehumidification. It also includes the second non-return valve 302 for limiting the circulation of said refrigerant in the prescribed direction, namely to said first indoor heat exchanger 6. Said system further comprises at least one return branch 502, said system being configured to circulate said refrigerant in said return branch 502 from the first indoor heat exchanger 6, in all or part of the operating variants of the sub-mode of air conditioning without dehumidification and in the sub-mode of air conditioning with dehumidification. Said refrigerant is at low pressure in said return branch 502. In the embodiment of Figures 1 to 7, said return branch 502 corresponds to the portion of the first flow line 28 located between the first indoor heat exchanger 6 and the liaison point 17.

Said system further comprises a first intermediate branch 504 connecting said first and second inner heat exchangers 6, 27, said intermediate first branch 504 being configured to be traversed in a first direction by the refrigerant, namely from said first indoor exchanger 6 to said second indoor exchanger 27, this at least in said air conditioning mode. Said intermediate branch 504 may in particular have a common part with said return branch 502. In the embodiment of Figures 1 to 7, the first intermediate branch 504 comprises said sixth circulation line 33. Said first intermediate branch 504 thus comprises the intermediate pressure regulator 400, sealed, and the intermediate non-return valve 306, configured to prohibit a circulation of the refrigerant of the second internal exchanger 27 to the first internal exchanger 6 by said intermediate branch 504.

Said system further comprises a branch 506, said link, said link branch 506 being configured to be traversed in a first direction by the refrigerant, namely from said second internal exchanger 27 to a return point of the refrigerant to low pressure, allowing in particular to direct said refrigerant to an inlet of the compressor 20, not visible in this figure, this at least in some of the variants of the air conditioning mode without dehumidification. Said connecting branch 506 may in particular be connected to the return branch 502. In the embodiment of FIGS. 1 to 7, said connecting branch 506 comprises the seventh circulation line 34. Said connecting branch thus comprises the valve of FIG. link 106, allowing or not, optionally, a circulation of the refrigerant in said connecting branch 506 and the connecting non-return valve 307, configured to prohibit a flow of refrigerant in said connecting branch 506 towards said second internal exchanger 27. Said system further comprises a second intermediate branch 508, connecting said second exchanger of inner heat 27 and said main supply branch 500, said second intermediate branch being configured to be traversed in a first direction by the refrigerant, at least in said heat pump mode, namely from said second exchanger 27 to said branch main supply 500. At one of its ends, said second intermediate branch 508 is here connected to the first intermediate branch 504, downstream of said intermediate expansion valve 400 and said intermediate non-return valve 306, according to the direction of circulation said refrigerant in said first intermediate branch. At the other of its ends, said second intermediate branch is connected to said main branch 500 between said second non-return valve 302 and said first expander 2. In the embodiment of FIGS. 1 to 7, said connecting branch 508 corresponds at the portion of the second circulation line 29 extending between the eleventh point of connection 211 and the sixth point of connection 206. Said connecting branch 508 thus comprises the fourth non-return valve 304. It is observed that the first expander 2 is located on said main power supply branch 500, between said second intermediate branch 508 and said first heat exchanger 6 so as to be traversed by said fluid both in said air conditioning mode and in said heat pump mode. Said system also comprises here another secondary supply branch 510, said system being configured to circulate said refrigerant to said second indoor heat exchanger 27, in said secondary supply branch 510, in said air conditioning mode and / or heat pump. Said fluid is at high pressure in said secondary supply branch 510. It comprises at least one non-return valve. Said second power supply branch 510 and said link branch 506 here comprise a common part, situated downstream of said non-return valve of said secondary supply branch 510, according to the direction of flow of the fluid in said supply branch. 510, and upstream of said connecting valve 106 and said link non-return valve 307, according to the fluid flow direction in said connecting branch 506. In the embodiment of FIGS. 1 to 7, said secondary supply branch 510 corresponds to the part of the second circulation line located between the first junction point 201 and the second heat exchanger 27. The non-return valve of said secondary supply branch 510 corresponds in this way to the third non-return valve 303.

It should be noted that the invention also relates to an air conditioning unit comprising a first 6 and said second 27 indoor heat exchangers, said unit being configured to operate in an air conditioning mode in which it takes heat in the flow of air I to be blown inside the compartment, using said first and second indoor heat exchangers 6, 27. Said unit has, for example, the configuration mentioned above in relation to Figure 8 It is intended to be used, in particular, in the system already described.

Various modes, sub-modes and variants of operation of said unit and of said system will now be illustrated in relation with FIGS. 1 to 7. By convention, in these figures, the circulation lines 28, 29, 30, 31, 32, 33, 34 through which no fluid flows are shown in broken lines, while the circulation lines 28, 29, 30, 31, 32, 33, 34 through which the refrigerant circulates are shown in solid lines.

In Figure 1, the refrigerant circuit is used in the first mode, called air conditioning, to cool the first air flow I prior to its delivery to the interior of the cabin, without dehumidification, this in a first variant of operation. In this configuration, the fourth control valve 104, the fifth control valve 105 and the connecting valve 106 are closed. The intermediate expansion valve 400 is also closed. Thus, the refrigerant borrows only the first line of circulation 28.

In other words, the refrigerant is compressed inside the compressor 20 to be brought to a high HP pressure, then flows to the first junction point 201, then passes through the second control valve 102 (open position), then circulates until second junction point 202, then circulates inside the external heat exchanger 21, operating in condenser / gas cooler, the refrigerant yielding calories to the external air flow E. Then, the refrigerant circulates until at the third junction point 203, then takes the first non-return valve 301, bypassing the second expansion member 23, then flows to the fourth junction point 204, then takes the high pressure branch 25 inside which the refrigerant transfers calories to the refrigerant present in the low pressure branch 26. Then, the refrigerant flows to the fifth point of junction 205, then takes the second non-return valve 302, then flows to the sixth point of junction 206 and through the first expansion member 2. Then, the refrigerant flows through the first indoor heat exchanger 6, operating as an evaporator, to cool dir the flow of air I intended to be blown inside the passenger compartment, then flows to the point of connection 17, passing through the seventh junction point 207, then passes through the third control valve 103 (position open), then flows to the ninth junction point 209, passing through the eighth junction point 208, then passes through the accumulator 18 inside which any liquid refrigerant residue is retained, then flows to the inside the low pressure branch 26 of the third heat exchanger 24 to return to the compressor 20. These arrangements are such that the refrigerant is at high pressure downstream of the compressor 20 to the first expansion member 2, and then at low pressure. downstream of said first expansion member 2 to the compressor 20.

In FIG. 2, the refrigerant circuit is used in the first mode, called air-conditioning, to cool the first air flow I before it is delivered inside the passenger compartment, without dehumidification, this in a second variant Operating. In this configuration, the fourth control valve 104 and the fifth control valve 105 are closed while the connecting valve 106 is open and the intermediate expansion valve 400 is open and active.

It is observed that said first intermediate branch, said second indoor heat exchanger and said link branch are connected in series, in this order, in the direction of circulation of the refrigerant. In this way they form a diversion route, here parallel mounting of said return branch. In other words, said circuit comprises a bypass path allowing the refrigerant to follow the same circuit when in the operating variant of FIG. 1, and also by paralleling in said bypass path, passing from the seventh connection point. 207 at the eighth point of connection 208 passing successively through the intermediate expansion valve 400, the intermediate check valve 306, the eleventh junction point 211, the second internal exchanger 27, the tenth junction point 210, the connecting valve 106 and the valve 307. As mentioned above, the two indoor heat exchangers 6, 27 then operates as an evaporator. As an alternative, the third control valve 103 may be closed so that the refrigerant circulates only in said bypass route.

In FIG. 3, the refrigerant circuit is used in the first mode, called air-conditioning, to cool the first air flow I before it is delivered inside the passenger compartment, without dehumidification, this in a third variant Operating. In this configuration, the third control valve 103, the fourth control valve 104 and the fifth control valve 105 are closed while the connecting valve 106 is open and the intermediate expansion valve 400 is open and active. In this variant, the fluid flows as in the variant of Figure 2 except that the refrigerant passes only in said branch path. Moreover, said first expander 2 is completely open and not active. In other words, the refrigerant only undergoes expansion at the level of said intermediate holder 400 upstream of which it is at high pressure and downstream of which it is at low pressure. As a result, only the second indoor heat exchanger 27 operates as an evaporator while the first indoor heat exchanger 6 operates as a condenser / gas cooler.

In such a mode, said first indoor heat exchanger 6 is configured to be traversed by an additional external air flow E 'so that the exchange surface of said external heat exchanger 21 and of said first indoor heat exchanger 6 is add up. Only the second indoor heat exchanger 27 contributes to cooling said air flow I intended to be blown into the compartment. In Figure 4, the refrigerant circuit is used in the first mode, called air conditioning, to cool the first air flow 7 prior to its delivery to the interior of the cabin, with dehumidification. In such a mode, the first indoor heat exchanger 6 is set at a very low temperature by restricting the opening of the first expansion member 2; the air flow I is therefore very cooled and dehumidified but, in order not to cool the cabin too much, it is heated by the second indoor heat exchanger 27.

In this configuration, the fifth control valve 105 and the connecting valve 106 are closed and the intermediate expansion valve 400 is closed. This mode differs from that of FIG. 1 in that the refrigerant also impinges on the second circulation line 29, said fourth control valve 104 being in an open configuration. The refrigerant therefore passes through said second indoor heat exchanger 27, operating as a condenser / gas cooler, from the first junction point 201 and toward the sixth junction point 206.

In FIG. 5, the refrigerant circuit is used in the second mode, called the heat pump, in which the first air stream 7 is heated before it is delivered inside the passenger compartment of the motor vehicle, without dehumidification. In this configuration, the second control valve 102, the third control valve 103 and the connecting valve 106 are closed. The intermediate expansion valve 400 may be closed without this being necessary. Indeed, the pressure is higher in the intermediate branch 508 which is then at a higher pressure than in the return branch 502.

Thus, the refrigerant borrows the second circulation line 29, the third circulation line 30, the fourth circulation line 31, the fifth circulation line 32 and partially the first circulation line 28. In other words, the refrigerant is compressed inside the compressor 20 to be brought to a high pressure HP, then flows to the first point of junction 201. The refrigerant then borrows the second line of circulation 29 and passes through the fourth control valve 104 (position open) and the third non-return valve 303 before passing through the second indoor heat exchanger 27 inside which the refrigerant yields calories to the air flow I intended to be blown into the passenger compartment to warm the latter before it is delivered to the interior of the passenger compartment of the motor vehicle, said second indoor heat exchanger 27 operating as a condenser / gas cooler . Then, the refrigerant passes through the fourth non-return valve 304 to reach the sixth junction point 206. Then the refrigerant passes through the first expansion member 2 which is completely open so that no expansion occurs therein. Then the refrigerant circulates inside the first indoor heat exchanger 6, operating as a condenser / gas cooler, to ensure preheating of the air flow I to be blown into the passenger compartment. It continues to the point of connection 17. Then, the refrigerant borrows the fourth circulation line 31 and passes through the fifth non-return valve 305 to reach the fifth junction point 205. Then, the refrigerant borrows the high pressure branch 25 of the internal heat exchanger 24 inside which the refrigerant yields calories to the refrigerant present inside the low pressure branch 26. Then the refrigerant reaches the fourth junction point 204 and then passes through the second organ of relaxation 23 and then circulates inside the external heat exchanger 21, operating as an evaporator, the refrigerant capturing calories to the outside air flow E, in other words it heats up in contact with the outside air flow E. Then the refrigerant reaches the second junction point 202 to take the third circulation line 30 and pass through the fifth control valve 10 5 (open position) and join the ninth junction point 209 to take the first line of circulation 28. The refrigerant then passes through the accumulator 18 inside which any residual liquid refrigerant is retained, then flows to the interior of the low pressure branch 26 of the internal heat exchanger 24 to return to the compressor 20.

These arrangements are such that the refrigerant is at high pressure HP downstream of the compressor 20 to the second expansion member 23, then at low pressure downstream of said second expansion member 23 to the compressor 20.

Alternatively, the first expander 2 may be partially active to bring the refrigerant to an intermediate pressure between said first expander 2 and said second expander 23. In FIG. 6, the refrigerant circuit is used in the second mode, called the heat pump, in which the first air stream 7 is heated prior to its delivery inside the passenger compartment of the motor vehicle, with dehumidification.

In this mode, the circulation of the refrigerant is identical to that of FIG. 5. The difference in operation lies in the fully active configuration of the first expansion member 2, said second expansion member 23 then being able to be in an inactive configuration while passing through the refrigerant without subjecting it to further relaxation. In this way, the refrigerant is at high pressure downstream of the compressor 20 to the first expansion member 2, then at low pressure downstream of said first expansion member 2 to the compressor 20. Said first indoor exchanger 6 then operates in the evaporator and the second indoor heat exchanger 27 in condenser / gas cooler.

It is found that, advantageously, said system is configured so that a heat exchange takes place between said refrigerant and itself in said internal heat exchanger 24 in said heat pump mode, with or without dehumidification. This improves the performance of the device by allowing more efficient heating of the air flow I intended to be blown into the passenger compartment, without having to provide additional power to the compressor 20.

For this, said system comprises a branch, namely here said circulation line 30, intended to be traversed by said refrigerant in the heat pump mode, at the outlet of said external heat exchanger 21, according to the direction of circulation of said refrigerant in said heat pump mode. In addition, said branch 30, said return branch in heat pump mode, is connected to said low pressure branch 26 at a point, namely here the ninth junction point 209, located upstream of said internal heat exchanger 24, according to the flow direction of said refrigerant in said heat pump mode.

Note that said system is configured so that, in said heat pump mode, said high pressure branch 25 is connected downstream of the first indoor heat exchanger 6 and upstream of said outdoor heat exchanger 21, according to the direction of circulation of said refrigerant in said heat pump mode.

Furthermore, said system is configured so that, in said cooling mode, said high pressure branch 25 is connected downstream of said external heat exchanger 21 and upstream of the first indoor heat exchanger 6, according to the direction of flow of said refrigerant in said air conditioning mode.

It is also noted that said system comprises a branch intended to be traversed by said refrigerant in the air conditioning mode, at the outlet of the first indoor heat exchanger 6, according to the direction of circulation of said refrigerant in said air conditioning mode. Said branch 40, said return branch in cooling mode, is connected to a branch point, namely again said ninth junction point 209, common to said low pressure branch 26 and said return branch in heat pump mode .

In addition, said system is configured so that, in heat pump mode, said accumulator 18 is located downstream of said bypass point 209 and upstream of said internal heat exchanger 24, according to the direction of circulation of said refrigerant in said pump mode heat.

As in the illustrated embodiment, said circuit is advantageously configured to enable the direction of circulation of the refrigerant in the high pressure branch 25 of the internal exchanger 24 to be reversed, between the air conditioning mode and the heat pump mode.

In FIG. 7, the refrigerant circuit is used in the third heat recovery mode in which it allows, at least temporarily, to continue to supply heat to the passenger compartment via the second interior exchanger 27 while so that the latter produces more heat than the first indoor heat exchanger 6 produces cold, without using the external heat exchanger 21.

In other words, said system is configured to operate, optionally, in said air conditioning mode, in said heat pump mode and in said heat recovery mode. In the latter mode, it draws heat from the airflow to be blown into the compartment using the first indoor heat exchanger 6 and releases it into the air stream to be blown at the same time. interior of the compartment with the aid of the second indoor heat exchanger 27 while said refrigerant bypasses said outdoor heat exchanger 21.

In this configuration, the second control valve 102, the fifth control valve 105 and the connecting valve 106 are closed and the intermediate expansion valve 400 is closed.

Thus, the refrigerant borrows the second circulation line 29 and partially the first circulation line 28. In other words, the refrigerant is compressed inside the compressor 20 to be brought to a high pressure HP, and then flows until first connecting point 201. The refrigerant then borrows the second circulation line 29 and passes through the fourth control valve 104 and the third non-return valve 303 before passing through the second indoor heat exchanger 27 inside which the refrigerant yields calories to the flow of air I intended to be blown into the passenger compartment to warm the latter prior to delivery within the passenger compartment of the motor vehicle, the second indoor heat exchanger operating in condenser / cooled gas.

Then, the refrigerant passes through the fourth non-return valve 304 to reach the sixth junction point 206. Then the refrigerant passes through the first expansion member 2 in which it undergoes expansion. Then the refrigerant circulates inside the first indoor heat exchanger 6, operating as an evaporator, where it captures calories in the air flow I intended to be blown into the passenger compartment. Indeed, it then comes from the cabin which has previously been heated and which it is desired to maintain at least temporarily the heating, while external heat exchanger 21 is not requested. Such a case is encountered, for example, in the event of icing of said external heat exchanger 21, making said external heat exchanger 21 non-operative. The refrigerant continues to the point of connection 17. Then, the fluid passes through the third control valve 103 to continue along the first flow line 28. The refrigerant then passes through the accumulator 18 inside which a possible residue liquid refrigerant is retained, then circulates inside the low pressure branch 26 of the internal heat exchanger 24, without heat exchange with the high pressure branch 26, to return to the compressor 20.

It is observed that said circuit keeps the same direction of circulation of the refrigerant in the first indoor heat exchanger 6, in all operating modes mentioned.

FIG. 9 illustrates a circuit similar to that of FIGS. 1 to 7 and further comprising a fifth heat exchanger 500 in series between said first expander 2 and said first indoor heat exchanger 6, in particular so as to be traversed by said fluid refrigerant, according to the different modes of operation mentioned above. Said fifth heat exchanger 600 is intended, for example, for the thermal conditioning of an energy storage unit such as an electric battery, in particular a large battery or a battery pack, or by direct heat exchange. or via a circulation loop of a heat transfer fluid.

FIG. 10 illustrates a variant of FIG. 9 in which said system comprises an additional bypass line of the first expander 2 and said first indoor heat exchanger 6, for example again to allow the thermal conditioning of a storage unit such as an electric battery, in particular a large battery or a battery pack.

Said additional circulation line is located between a twelfth 212 and a thirteenth 213 junction points of said refrigerant circulation circuit. Said twelfth junction point 212 is located between said junction point 206 and said first expander 2. Said thirteenth junction point 213 is located between said first indoor heat exchanger 6 and said seventh junction point 207.

Said additional circulation line comprises in this order, between said twelfth junction point 212 and said thirteenth junction point 213 a fourth expander 602, preferably sealed, and a fifth heat exchanger 604, for heat exchange with said energy reserve unit. Said additional circulation line may be active in at least some of the modes of operation mentioned above, according to the thermal regulation needs of the energy reserve unit.

It can be observed that in the various embodiments illustrated, the system is configured to be used, optionally, in different modes, sub-modes and variants of operation, among which the configuration in which, according to the invention, it takes from the heat in the air flow I to be blown inside the compartment, using said first and second indoor heat exchangers 6, 27, and rejects it outside the compartment, using the external heat exchanger 21, this configuration corresponding to the sub-mode without dehumidification air conditioning mode, and this in a particular variant. According to a simplified version, said configuration is the only possible, in air conditioning mode. Alternatively, said configuration is the only possible in the sub-mode of air conditioning, without dehumidification. According to another variant not illustrated, said system comprises a bypass branch of said internal exchanger at said high pressure branch 25. This makes it possible to reduce the pressure losses in said internal exchanger when heat exchange at said heat exchanger internal 24 is not desired.

Claims

An air conditioning system for a compartment, said system comprising:

an external heat exchanger (21) for exchanging heat between a refrigerant and a flow of air (E) circulating outside the compartment,

- a first (6) and a second (27) inner heat exchanger for performing a heat exchange involving the refrigerant;

said system being configured to operate in an air conditioning mode in which it draws heat from a flow of air (I) to be blown into the compartment, using said first and second indoor heat exchangers ( 6, 27) and discharges it outside the compartment by means of the external heat exchanger (21).

The system of claim 1 wherein said system comprises:

at least one main supply branch (500), said system being configured to circulate said high pressure refrigerant to at least one of said first (6) and / or second (27) indoor heat exchangers in said main power supply branch (500), in said air conditioning mode, and / or

at least one return branch (502), said system being configured to circulate said low pressure refrigerant from at least one of said first (6) and / or second (27) indoor heat exchangers in said branch of return (502) in said air conditioning mode.

3. System according to the preceding claim wherein said system further comprises a first intermediate branch (504) connecting said first (6) and second (27) inner heat exchangers, said first intermediate branch (504) being configured to be traversed according to a first direction by the refrigerant, in said air conditioning mode, from said first indoor heat exchanger (6) to said second indoor heat exchanger (27).

4. System according to the preceding claim wherein said first intermediate branch (504) comprises an expander (400), said intermediate.

5. System according to the preceding claim wherein said intermediate expander (400) is a sealed pressure reducer.

6. System according to any one of claims 3 to 5 wherein said first intermediate branch further comprises a non-return valve (306), said intermediate anti-return valve, configured to prohibit a flow of refrigerant in said first branch intermediate (504) in a direction opposite to the first sense.

7. System according to any one of claims 3 to 6 wherein said system further comprises a branch (506), said link, said link branch (506) being configured to be traversed in a first direction by the fluid refrigerant, in said air conditioning mode, from said second indoor heat exchanger (27).

8. System according to the preceding claim wherein said link branch

(506) comprises a valve (106), said connecting, optionally allowing or not a flow of refrigerant in said connecting branch (506).

9. System according to any one of claims 7 or 8 wherein said connecting branch (506) further comprises a non-return valve (307), said connecting non-return valve, configured to prohibit a flow of refrigerant in said link branch (506) in a direction opposite to the first direction.

The system according to any one of claims 7 to 9 wherein said first intermediate branch (504), said second indoor heat exchanger (27) and said link branch (506) are connected in series, in that order, according to a direction of circulation of the refrigerant in the air conditioning mode, so as to form a bypass route.

11. System according to the preceding claim wherein said branch path is connected in parallel with said return branch (502).

The system of any one of claims 2 to 11 wherein said system is further configured to operate in a heat pump mode in which it draws heat from the air outside the compartment to the heat pump. using the external heat exchanger (21) and reject it in a flow of air (I) to be blown to inside the compartment using the first (6) and second (27) indoor heat exchangers.

The system of claim 12 wherein said system comprises at least one other secondary supply branch (510) for circulating the high pressure refrigerant to at least one of said first and second heat exchangers in the world heat pump.

The system of any one of claims 12 or 13 including a second intermediate branch (508) connecting said second (27) indoor heat exchanger and said main power branch (500), said second intermediate branch (508) being configured to be traversed in a first direction by the refrigerant, in said heat pump mode, from said second heat exchanger (27) to said main supply branch (500).

15. System according to the preceding claim wherein a first expander (2) is located on said main supply branch (500) between said second intermediate branch (508) and said first heat exchanger (6) so as to be traversed by said fluid as well in said air conditioning mode as in said heat pump mode.

16. A method of air conditioning using the air conditioning system according to any one of the preceding claims.