Indirect reversible air-conditioning circuit for a motor vehicle and corresponding operating method

文档序号：1617960 发布日期：2020-01-10 浏览：8次中文

阅读说明：本技术 用于机动车辆的间接可逆空调回路及相应的操作方法 (Indirect reversible air-conditioning circuit for a motor vehicle and corresponding operating method ) 是由 J.贝努阿里于 2018-03-30 设计创作，主要内容包括：本发明涉及一种用于机动车辆的间接空调回路(1),其包括：第一制冷剂回路(A),包括：压缩机(3),第一减压装置(7),第一热交换器(9),第二减压装置(11),第二热交换器(13),和用于绕过所述第二热交换器(13)的、包括第一截止阀(33)的第一管道(30)；第二传热流体回路(B)；第一双流体热交换器(5)；第一内部热交换器(19)；第二内部热交换器(19’)；和用于绕过第一减压装置(7)和所述第一热交换器(9)的第二管道(40),第二管道(40)包括第三减压装置(17),该第三减压装置布置在第二双流体热交换器(15)的上游,第二双流体热交换器(15)也联合地布置在次级热管理回路上。(The invention relates to an indirect air-conditioning circuit (1) for a motor vehicle, comprising: a first refrigerant circuit (A) comprising: -a compressor (3), -a first pressure reducing device (7), -a first heat exchanger (9), -a second pressure reducing device (11), -a second heat exchanger (13), and-a first conduit (30) comprising a first shut-off valve (33) for bypassing said second heat exchanger (13); a second heat transfer fluid circuit (B); a first two-fluid heat exchanger (5); a first internal heat exchanger (19); a second internal heat exchanger (19'); and a second conduit (40) for bypassing the first pressure reducing device (7) and said first heat exchanger (9), the second conduit (40) comprising a third pressure reducing device (17) arranged upstream of the second dual-fluid heat exchanger (15), the second dual-fluid heat exchanger (15) also being jointly arranged on the secondary thermal management circuit.)

1. An indirect air-conditioning circuit (1) for a motor vehicle, comprising:

a first refrigerant fluid circuit (A) in which a refrigerant fluid flows, the first refrigerant fluid circuit (A) comprising, in the direction of flow of the refrigerant fluid:

a compressor (3) for compressing the refrigerant,

a first two-fluid heat exchanger (5),

a first expansion device (7),

a first heat exchanger (9) intended to be crossed by an internal air flow (10) of the motor vehicle,

a second expansion device (11),

a second heat exchanger (13) intended to be crossed by an external air flow (200) of the motor vehicle, and

a first bypass conduit (30) of the second heat exchanger (13) comprising a first shut-off valve (33),

a second heat transfer fluid circuit (B) in which a heat transfer fluid flows, and

a first two-fluid heat exchanger (5) jointly arranged: on said first refrigerant fluid circuit (A) downstream of said compressor (3), between said compressor (3) and said first expansion device (7); and on the second heat transfer fluid circuit (B) so as to allow heat exchange between the first refrigerant fluid circuit (A) and the second heat transfer fluid circuit (B),

a first internal heat exchanger (19) allowing heat exchange between a high pressure refrigerant fluid at the outlet of the first two-fluid heat exchanger (5) and a low pressure refrigerant fluid at the outlet of the second heat exchanger (13) or of the first bypass duct (30),

a second internal heat exchanger (19') allowing heat exchange between a high pressure refrigerant fluid at the outlet of said first internal heat exchanger (19) and a low pressure refrigerant fluid flowing in said first bypass conduit (30),

a second bypass conduit (40) of the first expansion device (7) and of the first heat exchanger (9), the second bypass conduit (40) comprising a third expansion device (17) arranged upstream of a second dual fluid heat exchanger (15), the second dual fluid heat exchanger (15) also being jointly arranged on a secondary thermal management circuit.

2. Indirect reversible air conditioning circuit (1) as claimed in claim 1, characterized in that said second bypass duct (40) is connected on the one hand upstream of said first expansion device (7) and on the other hand upstream of said first shut-off valve (33) and of said second internal heat exchanger (19') to said first bypass duct (30).

3. Indirect reversible air conditioning circuit (1) as claimed in claim 1, characterized in that said second bypass duct (40) is connected on the one hand upstream of said first expansion device (7) and on the other hand upstream of said second internal heat exchanger (19) and of said first shut-off valve (33') to said first bypass duct (30).

4. Indirect reversible air conditioning circuit (1) as claimed in claim 1, characterized in that said second bypass duct (40) is connected on the one hand upstream of said first expansion device (7) and on the other hand downstream of the second expansion device (19') between said second expansion device (19') and said first internal heat exchanger (19).

5. Indirect reversible air conditioning circuit (1) as claimed in claim 1, characterized in that the first refrigerant fluid circuit (a) comprises a branch conduit (70), the branch conduit (70) being connected on the one hand to the first bypass conduit (30) upstream of the shut-off valve (33) of the second heat exchanger (19') and on the other hand to the third expansion device (17) upstream of the third expansion device (17) between the third expansion device (17) and the second shut-off valve (17), the branch conduit (70) comprising a third shut-off valve (74).

6. The indirect reversible air conditioning circuit (1) according to any of the preceding claims, characterized in that the second heat transfer fluid circuit (B) comprises:

said first two-fluid heat exchanger (5),

a first heat transfer fluid flow duct (50) comprising a third heat exchanger (54) for being crossed by an internal air flow 100 of the motor vehicle and connecting a first junction point (61) arranged downstream of the first dual-fluid heat exchanger (5) with a second junction point (62) arranged upstream of the first dual-fluid heat exchanger (5),

a second heat transfer fluid flow duct (60) comprising a fourth heat exchanger (64) for being crossed by an external air flow 200 of the motor vehicle and connecting a first junction point (61) arranged downstream of the first dual-fluid heat exchanger (5) with a second junction point (62) arranged upstream of the first dual-fluid heat exchanger (5), and

-a pump (18) arranged downstream or upstream of said first dual fluid heat exchanger (5), between said first junction point (61) and said second junction point (62).

7. An operating method for operating an indirect reversible air-conditioning circuit (1) according to claim 6 according to a parallel secondary cooling mode, wherein:

the refrigerant fluid flows into the compressor (3) where it enters at high pressure and flows in turn into the first dual-fluid heat exchanger (5), the first internal heat exchanger (19) and the second internal heat exchanger (19'):

a first portion of said refrigerant fluid enters said second bypass conduit (40), enters said third expansion device (17), at said third expansion device (17) said refrigerant fluid enters a low pressure, and then said low pressure refrigerant fluid flows into said second dual fluid heat exchanger (15) and then joins with the low pressure refrigerant fluid from said first heat exchanger (9) upstream of said first internal heat exchanger (19),

a second portion of said refrigerant fluid enters said first expansion device (7), where it becomes at low pressure, and then it flows in sequence into said first heat exchanger (9), into said first bypass conduit (30), into said second internal heat exchanger (19') at said first bypass conduit (30), then into said first internal heat exchanger (19), and then back to said compressor (3),

the heat transfer fluid at the outlet of the first dual fluid heat exchanger (5) flows into the fourth heat exchanger (64) of the second flow duct (50).

8. An operating method for operating an indirect reversible air-conditioning circuit (1) according to claim 6 according to a strict secondary cooling mode, wherein:

said refrigerant fluid flows into a compressor (3), where it is brought to a high pressure and flows in turn into said first dual fluid heat exchanger (5), said first internal heat exchanger (19), said second internal heat exchanger (19'), then it enters said second bypass conduit (40), enters said third expansion device (17), where it is brought to a low pressure, in said third expansion device (17), said low pressure refrigerant fluid then flows into said second dual fluid heat exchanger (15),

the heat transfer fluid at the outlet of the first dual fluid heat exchanger (5) flows into the fourth heat exchanger (64) of the second flow duct (50).

9. Operating method for operating an indirect reversible air conditioning circuit (1) according to claim 6 in combination with claims 3 to 5 according to a parallel secondary heat pump mode, wherein:

a first portion of said refrigerant fluid passes through said second bypass conduit (40) by passing through said third expansion device (17), where said refrigerant fluid enters a low pressure, passes through said second dual fluid heat exchanger (15), and then merges with the refrigerant fluid from said second heat exchanger upstream of said first internal heat exchanger (19),

a second portion of the refrigerant fluid passes through the first expansion device (7), where the refrigerant fluid becomes intermediate pressure, and then flows into the first heat exchanger (9), the second expansion device (11), where the refrigerant fluid becomes low pressure, and then flows into the second heat exchanger (13),

the low-pressure refrigerant fluid then passes through the first internal heat exchanger (19) and then returns to the compressor (3),

the heat transfer fluid at the outlet of the first two-fluid heat exchanger (5) flows only into the third heat exchanger (54) of the first flow duct (50).

10. An operating method for operating an indirect reversible air conditioning circuit (1) according to claim 6 in combination with claim 5 according to a strictly secondary heat pump mode, wherein:

said refrigerant fluid flowing into said compressor (3), said refrigerant fluid being at a high pressure in said compressor (3) and flowing in turn into said first dual fluid heat exchanger (5), said first internal heat exchanger (19), said second internal heat exchanger (19'), said first expansion device (7), at said first expansion device (7), said refrigerant fluid being at an intermediate pressure, said refrigerant fluid then flowing in turn into said first heat exchanger (9), said first bypass conduit (30), said branch conduit (70), said third expansion device (17), in said third expansion device (17), said refrigerant fluid being brought to a low pressure and then flowing into said second dual fluid heat exchanger (15), then the low pressure refrigerant fluid passing through said first internal heat exchanger (19) and then returning to said compressor (3),

the heat transfer fluid at the outlet of the first two-fluid heat exchanger (5) flows only into the third heat exchanger (54) of the first flow duct (50).

Technical Field

The present invention relates to the field of motor vehicles, and more particularly to a motor vehicle air conditioning circuit and method of operating the same.

Background

Current motor vehicles increasingly include air conditioning circuits. Typically, in a "conventional" air conditioning circuit, the refrigerant fluid enters sequentially: a compressor; a first heat exchanger, called condenser, placed in contact with the external air flow of the motor vehicle to release heat; an expansion device; and a second heat exchanger, called evaporator, placed in contact with the internal air flow of the motor vehicle to cool it.

There are also more complex air-conditioning circuit architectures which make it possible to obtain a reversible air-conditioning system, i.e. it can absorb the thermal energy in the outside air at a first heat exchanger, then called evaporative condenser, and then return the thermal energy to the interior of the vehicle, in particular through a dedicated third heat exchanger.

This may be achieved, in particular, by using an indirect air conditioning circuit. Indirect is here understood to mean that the air conditioning circuit comprises two flow circuits of two separate fluids, for example a refrigerant fluid and glycol water, in order to carry out various heat exchanges.

Thus, the air conditioning circuit comprises: a first refrigerant fluid circuit in which a refrigerant fluid flows; a second heat transfer fluid circuit in which a heat transfer fluid flows; and a two-fluid heat exchanger disposed in association on the first refrigerant fluid circuit and the second heat transfer fluid circuit to allow heat exchange between said circuits.

Such an air conditioning circuit makes it possible to be used according to different operating modes, however, as part of an electric or hybrid vehicle, the elements such as the battery and the electronic components are thermally managed by a secondary thermal management circuit. This configuration increases the production costs and the heat generated by these elements is lost, which could be reused for heating the interior of the vehicle and thus reduce the consumption of electrical energy in the heat pump mode of the air-conditioning circuit.

It is therefore an object of the present invention to at least partly overcome the drawbacks of the prior art and to provide an improved air conditioning circuit which also allows thermal management of elements such as batteries, electronic components and electric motors, in particular in electric or hybrid vehicles.

Disclosure of Invention

Accordingly, the present invention relates to an indirect air conditioning system for a motor vehicle, comprising:

a first refrigerant fluid circuit in which a refrigerant fluid flows, the first refrigerant fluid circuit comprising, in a flow direction of the refrigerant fluid:

a compressor for compressing the refrigerant to be compressed,

a first two-fluid heat exchanger having a first fluid flow path,

a first expansion device for expanding the air in the air conditioner,

a first heat exchanger for being traversed by an internal air flow of the motor vehicle,

a second expansion device for expanding the gas flow in the second expansion device,

a second heat exchanger for being crossed by an external air flow of the motor vehicle, an

A first bypass conduit of the second heat exchanger, including a first shut-off valve,

a second heat transfer fluid circuit in which a heat transfer fluid flows,

a first two-fluid heat exchanger arranged in combination: a first refrigerant fluid circuit downstream of the compressor between the compressor and the first expansion device; and a second heat transfer fluid circuit to allow heat exchange between the first refrigerant fluid circuit and the second heat transfer fluid circuit,

a first internal heat exchanger allowing heat exchange between a high pressure refrigerant fluid at the outlet of the first two-fluid heat exchanger and a low pressure refrigerant fluid at the outlet of the second heat exchanger or of the first bypass conduit,

a second internal heat exchanger allowing heat exchange between a high-pressure refrigerant fluid at an outlet of the first internal heat exchanger and a low-pressure refrigerant fluid flowing in the first bypass pipe,

a second bypass conduit of the first expansion device and the first heat exchanger, the second bypass conduit including a third expansion device disposed upstream of a second dual-fluid heat exchanger also disposed in combination on the secondary thermal management circuit.

According to one aspect of the present invention, the second bypass conduit is connected to the bypass conduit upstream of the first expansion device on the one hand, and upstream of the first shut-off valve and the second internal heat exchanger on the other hand.

According to a further aspect of the invention, the second bypass conduit is connected on the one hand upstream of the first expansion device and on the other hand upstream of the second heat exchanger and downstream of the first shut-off valve to the bypass conduit.

According to another aspect of the invention, a second bypass conduit is connected upstream of the first expansion device on the one hand and downstream of the second expansion device between said second expansion device and the first internal heat exchanger on the other hand.

According to another aspect of the invention, the first refrigerant fluid circuit comprises a branch conduit connected on the one hand to the first bypass conduit upstream of the shut-off valve of the second heat exchanger and on the other hand between said third expansion device and the second shut-off valve upstream of the third expansion device, said branch conduit comprising a third shut-off valve.

According to another aspect of the invention, the second heat transfer fluid circuit comprises:

a first two-fluid heat exchanger having a first fluid flow path,

a first heat transfer fluid flow duct comprising a third heat exchanger for being crossed by an external air flow of the motor vehicle and connecting a first junction point arranged downstream of the first dual-fluid heat exchanger and a second junction point arranged upstream of said first dual-fluid heat exchanger,

a second heat transfer fluid flow duct comprising a fourth heat exchanger intended to be crossed by the external air flow of the motor vehicle and connecting a first junction point arranged downstream of the first dual-fluid heat exchanger and a second junction point arranged upstream of said first dual-fluid heat exchanger, and

a pump disposed downstream or upstream of the first dual-fluid heat exchanger between the first junction point and the second junction point.

The invention also relates to an operating method for operating an indirect reversible air conditioning circuit according to a parallel secondary cooling mode, wherein:

a refrigerant fluid flows into the compressor, where the refrigerant fluid becomes high pressure and flows into the first dual fluid heat exchanger, the first inner heat exchanger, and the second inner heat exchanger in this order:

a first portion of the refrigerant fluid enters the second bypass line, enters a third expansion device where it becomes low pressure, then flows into the second dual fluid heat exchanger, and then merges with the low pressure refrigerant fluid from the first heat exchanger upstream of the first interior heat exchanger,

a second portion of the refrigerant fluid enters a first expansion device where it becomes at a low pressure, and then it flows in sequence into the first heat exchanger, a first bypass line where it flows into the second internal heat exchanger, then into the first internal heat exchanger, and then back to the compressor,

the heat transfer fluid at the outlet of the first dual fluid heat exchanger flows into the fourth heat exchanger of the second flow conduit.

The invention also relates to an operating method for operating an indirect reversible air conditioning circuit according to a strict secondary cooling mode, wherein:

the refrigerant fluid flows into the compressor where it becomes high pressure and flows sequentially into the first dual fluid heat exchanger, the first interior heat exchanger, the second interior heat exchanger, then the refrigerant fluid enters the second bypass conduit into the third expansion device where it becomes low pressure, which then flows into the second dual fluid heat exchanger,

the heat transfer fluid at the outlet of the first dual fluid heat exchanger flows into the fourth heat exchanger of the second flow conduit.

The invention also relates to an operating method for operating an indirect reversible air conditioning circuit according to a parallel secondary heat pump mode, wherein:

the refrigerant fluid flows into the compressor where it turns to a high pressure and flows sequentially into the first dual fluid heat exchanger, the first internal heat exchanger and the second internal heat exchanger:

a first portion of the refrigerant fluid passes through a second bypass conduit by passing through a third expansion device wherein the refrigerant fluid enters a low pressure, passes through a second dual fluid heat exchanger, and then merges with the refrigerant fluid from the second heat exchanger upstream of the first internal heat exchanger,

a second portion of the refrigerant fluid passes through a first expansion device where the refrigerant fluid becomes at an intermediate pressure and then flows sequentially into a first heat exchanger, a second expansion device where the refrigerant fluid becomes at a low pressure and then flows into a second heat exchanger,

the low pressure refrigerant fluid then passes through a first internal heat exchanger, then back to the compressor,

the heat transfer fluid at the outlet of the first dual fluid heat exchanger flows only into the third heat exchanger of the first flow conduit.

The invention also relates to an operating method for operating an indirect reversible air conditioning circuit according to a strict secondary heat pump mode, wherein:

the refrigerant fluid flows into the compressor where it is at a high pressure and flows sequentially into the first dual fluid heat exchanger, the first internal heat exchanger, the second internal heat exchanger, the first expansion device where it is at an intermediate pressure, the refrigerant fluid then flowing sequentially into the first heat exchanger, the first bypass conduit, the branch conduit, the third expansion device where it enters a low pressure and then flows into the second dual fluid heat exchanger, the low pressure refrigerant fluid then passing through the first internal heat exchanger and then returning to the compressor,

the heat transfer fluid at the outlet of the first dual fluid heat exchanger flows only into the third heat exchanger of the first flow conduit.

Drawings

Other characteristics and advantages of the invention will become clearer from reading the following description, given by way of illustrative and non-limiting example, with reference to the attached drawings, in which:

fig. 1 shows a schematic diagram of an indirect reversible air conditioning circuit according to a first embodiment;

FIG. 2 shows a schematic diagram of an indirect reversible air conditioning circuit according to a second embodiment;

FIG. 3 shows a schematic diagram of an indirect reversible air conditioning circuit according to a third embodiment;

FIG. 4 shows a schematic diagram of an indirect reversible air conditioning circuit according to a fourth embodiment;

FIG. 5 illustrates an expansion device according to an alternative embodiment;

FIG. 6 illustrates a schematic diagram of a second heat transfer fluid circuit of the indirect reversible air conditioning circuit of FIGS. 1-4 in accordance with an alternative embodiment;

fig. 7a shows the indirect reversible air conditioning circuit of fig. 1 to 3 according to a cooling mode;

FIG. 7b illustrates the indirect reversible air conditioning circuit of FIG. 4 according to a cooling mode;

FIG. 8a illustrates the indirect reversible air conditioning circuit of FIG. 1 according to a parallel secondary cooling mode;

FIG. 8b illustrates the indirect reversible air conditioning circuit of FIG. 2 according to a parallel secondary cooling mode;

FIG. 8c illustrates the indirect reversible air conditioning circuit of FIG. 3 according to a parallel secondary cooling mode;

FIG. 8d illustrates the indirect reversible air conditioning circuit of FIG. 4 according to a parallel secondary cooling mode;

FIG. 9a illustrates the indirect reversible air conditioning circuit of FIG. 1 according to a strict secondary cooling mode;

FIG. 9b illustrates the indirect reversible air conditioning circuit of FIG. 2 according to a strict secondary cooling mode;

FIG. 9c illustrates the indirect reversible air conditioning circuit of FIG. 3 according to a strict secondary cooling mode;

FIG. 9d illustrates the indirect reversible air conditioning circuit of FIG. 4 according to a strict secondary cooling mode;

fig. 10a shows the indirect reversible air conditioning circuit of fig. 1 to 3 according to a heat pump mode;

FIG. 10b illustrates the indirect reversible air conditioning circuit of FIG. 4 according to a heat pump mode;

FIG. 11a illustrates the indirect reversible air conditioning circuit of FIG. 2 according to a parallel secondary heat pump mode;

FIG. 11b illustrates the indirect reversible air conditioning circuit of FIG. 3 according to a parallel secondary heat pump mode;

FIG. 11c shows the indirect reversible air conditioning circuit of FIG. 4 according to a heat pump mode;

FIG. 12 illustrates the indirect reversible air conditioning circuit of FIG. 4 according to a strict secondary heat pump mode;

Detailed Description

Like elements in the various figures have like reference numerals.

The following are examples of embodiments. While the description refers to one or more embodiments, this does not necessarily mean that each reference refers to the same embodiment, or that the features only apply to a single embodiment. Individual features of different embodiments may also be combined or interchanged to provide further embodiments.

In this description, certain elements or parameters may be numbered, for example, a first element or a second element and a first parameter and a second parameter or a first criterion or a second criterion, etc. In this case, simple numbering is used to distinguish and name similar but not identical elements or parameters or standards. This numbering does not imply a priority of one element, parameter or criteria over another, and these designations may be readily interchanged without departing from the scope of the present description. Neither does the numbering imply a temporal order, such as for evaluating a particular criterion.

In the present description, the term "placed upstream" is understood to mean that an element is placed before another element with respect to the direction of flow of the fluid. Conversely, the term "placed downstream" is understood to mean that an element is placed behind another element with respect to the flow direction of the gas fluid.

Fig. 1 shows an indirect air conditioning circuit 1 for a motor vehicle. The indirect air conditioning circuit 1 mainly includes:

a first refrigerant fluid circuit A, in which a refrigerant fluid flows,

a second heat transfer fluid circuit B in which a heat transfer fluid flows, and

a first two-fluid heat exchanger 5, arranged both on the first refrigerant fluid circuit a and on the second heat transfer fluid circuit B, so as to allow heat exchange between said first refrigerant fluid circuit a and said second heat transfer fluid circuit B,

the first refrigerant fluid circuit a more specifically comprises, in the direction of flow of the refrigerant fluid:

o a compressor 3, a compressor control unit,

-a first dual fluid heat exchanger 5 disposed downstream of said compressor 3,

o a first expansion device 7 for expanding the gas flow,

a first heat exchanger 9 for being crossed by an internal air flow 10 of the motor vehicle,

o a second expansion device 11,

a second heat exchanger 13 for being exposed to an external air flow 200 of the motor vehicle, an

Omicron a first bypass conduit 30 of the second heat exchanger 13.

The first bypass duct 30 may more specifically connect the first connection point 31 and the second connection point 32.

The first connection point 31 is preferably arranged downstream of the first heat exchanger 9, in the flow direction of the refrigerant fluid, between said first heat exchanger 9 and the second heat exchanger 13. More specifically, as shown in fig. 1, the first connection point 31 is arranged between the first heat exchanger 9 and the second expansion device 11. However, it is fully conceivable that the first connection point 31 is provided between the second expansion means 11 and the second heat exchanger 13, as long as the refrigerant fluid can bypass said second expansion means 11 or pass the second expansion means 11 without experiencing any pressure loss.

The second connection point 32 is then preferably arranged downstream of the second heat exchanger 13, between said heat exchanger 13 and the compressor 3.

To control the passage or non-passage of refrigerant fluid in the first bypass conduit 30, the latter comprises a first shut-off valve 33. In order to exclude the refrigerant fluid from passing through the second heat exchanger 13, the second expansion device 11 may in particular have a shut-off function, i.e. it is able to prevent the flow of refrigerant fluid when it is closed. An alternative may be to have a shut-off valve between the second expansion means 11 and the first connection point 31.

Another alternative (not shown) may also have a three-way valve at the first connection point 31.

The first refrigerant fluid circuit a may further comprise a non-return valve 23, which non-return valve 23 is arranged downstream of the second heat exchanger 13, between said second heat exchanger 13 and the second connection point 32, to prevent the refrigerant fluid from the first bypass conduit 30 from flowing back towards the second heat exchanger 13.

A shut-off valve, a check valve, a three-way valve or an expansion device with a shut-off function is to be understood here as a mechanical or electromechanical element which can be controlled by an electronic control unit embedded in the motor vehicle.

The first refrigerant fluid circuit a also comprises a first Internal heat exchanger 19 (IHX), which first Internal heat exchanger 19 allows heat exchange between the high pressure refrigerant fluid at the outlet of the first two-fluid heat exchanger 5 and the low pressure refrigerant fluid at the outlet of the second heat exchanger 13 or of the first bypass conduit 30. The first internal heat exchanger 19 comprises in particular an inlet and an outlet for a low-pressure refrigerant fluid originating from the second connection point 32, and an inlet and an outlet for a high-pressure refrigerant originating from the first dual-fluid heat exchanger 5.

A high pressure refrigerant fluid is herein understood to mean a refrigerant fluid that has experienced a pressure increase at the compressor 3 and has not experienced a pressure loss due to one of the expansion devices. A low-pressure refrigerant fluid is understood herein to mean a refrigerant fluid that has undergone a pressure loss and has a pressure close to the pressure at the inlet of the compressor 3.

The first refrigerant fluid circuit a also comprises a second internal heat exchanger 19', which second internal heat exchanger 19' allows heat exchange between the high-pressure refrigerant fluid at the outlet of the first internal heat exchanger 19 and the low-pressure refrigerant fluid flowing in the first bypass conduit 30. This second internal heat exchanger 19' comprises, in particular, an inlet and an outlet for a low-pressure refrigerant fluid originating from the first connection point 31 and an inlet and an outlet for a high-pressure refrigerant fluid originating from the first internal heat exchanger 19. As shown in fig. 1, the second internal heat exchanger 19' may be arranged downstream of the first shut-off valve 33.

At least one of the first internal heat exchanger 19 or the second internal heat exchanger 19' may be a coaxial heat exchanger, i.e. comprising two coaxial tubes and exchanging heat between the two coaxial tubes.

Preferably, the first internal heat exchanger 19 may be a coaxial internal heat exchanger having a length in the range of 50 to 120mm, and the second internal heat exchanger 19' may be a coaxial internal heat exchanger having a length in the range of 200 to 700 mm.

The first refrigerant fluid circuit a may also comprise a desiccant cylinder 14, which desiccant cylinder 14 is arranged downstream of the first two-fluid heat exchanger 5, more precisely between said first two-fluid heat exchanger 5 and the first internal heat exchanger 19. Such desiccant cylinders, which are arranged on the high pressure side of the air-conditioning circuit, i.e. downstream of the two-fluid heat exchanger 5 and upstream of the expansion device, have a smaller space requirement and lower costs than other phase separation solutions, such as accumulators, which are to be arranged on the low pressure side of the air-conditioning circuit, i.e. upstream of the compressor 3, in particular upstream of the first internal heat exchanger 19.

The first expansion device 7 and the second expansion device 11 may be electronic expansion valves, i.e. the pressure of the refrigerant fluid at its outlet is controlled by an actuator which sets the opening area of the expansion devices and thus the pressure of the fluid at the outlet. Such an electronic expansion valve is particularly capable of allowing refrigerant fluid to pass therethrough without loss of pressure when the expansion device is fully open.

According to a preferred embodiment, the first expansion means 7 is an electronic expansion valve controllable by a control unit installed in the vehicle, and the second expansion means 11 is a thermostatic expansion valve.

The second expansion device 11 may in particular be a thermostatic expansion valve with a shut-off function. In this case, the first expansion means 7 and the second expansion means 11 can be bypassed by a branch conduit a', which in particular comprises a shut-off valve 25, as shown in fig. 5. The branch conduit a' allows refrigerant fluid to bypass the first expansion device 7 and the second expansion device 11 without experiencing pressure loss. Preferably, at least the second expansion means 11 is a thermostatic expansion valve comprising a branch conduit a'. The first expansion device 7 may also comprise a shut-off function or a shut-off valve downstream to prevent or not prevent the passage of refrigerant fluid.

The first refrigerant fluid circuit a further comprises a second bypass conduit 40 of the first expansion device 7 and of the first heat exchanger 9. The second bypass conduit 40 includes a third expansion device 17 disposed upstream of the second dual fluid heat exchanger 15. The second two-fluid heat exchanger 15 is also jointly arranged on the secondary thermal management circuit. The second thermal management circuit may more particularly be a circuit in which a heat transfer fluid flows and is connected to a cold plate or a heat exchanger in the battery and/or the electronic component.

The third expansion device 17 may also include a shut-off function to allow or disallow refrigerant fluid to pass through the second bypass conduit 40. An alternative is to have a shut-off valve in the second bypass conduit upstream of the third expansion device 17.

The second bypass conduit 40 is connected on the one hand upstream of the first expansion device 7. This connection is made between the second heat exchanger 19' and said first expansion means 7 at a third connection point 41 arranged upstream of the first expansion means 7.

On the other hand, according to the first embodiment shown in fig. 1, the second bypass conduit 40 is connected to the first bypass conduit 30 upstream of the first shut-off valve 33 and the second internal heat exchanger 19'. As shown in fig. 1, when the first cut-off valve 33 is arranged upstream of the second internal heat exchanger 19', the connection is made at a fourth connection point 42 arranged between the first cut-off valve 33 and the first connection point 33.

According to a second embodiment shown in fig. 2, the second bypass duct 40 is on the other hand connected to the first bypass duct 30 upstream of the second heat exchanger 19' and downstream of the first shut-off valve 33. As shown in fig. 2, when the first shut-off valve 33 is arranged upstream of the second internal heat exchanger 19', the fourth connection point 42 is then arranged between the first shut-off valve 33 and the second heat exchanger 19'.

Fig. 3 shows a third embodiment of the invention, in which a second bypass conduit 40 is connected upstream of the first expansion device 7 on the one hand, and downstream of the second expansion device 19 'on the other hand, between said second expansion device 19' and the first internal heat exchanger 19. The third connection point 41 is therefore also arranged upstream of the first expansion device 7, between the second heat exchanger 19' and said first expansion device 7.

In the example of fig. 3, the fourth connection point 42 is arranged downstream of the first bypass duct 30, between the second connection point 32 and the first internal heat exchanger 19. However, it is also fully conceivable for the fourth connection point 42 to be arranged on the first bypass duct 30 downstream of the first shut-off valve 33 and of the second internal heat exchanger 19'.

The fourth embodiment depicted in fig. 4 is identical to the embodiment in fig. 3, except that the first refrigerant fluid circuit a comprises a branch conduit 70 connected on the one hand to the first bypass conduit 30 upstream of the first shut-off valve 33 and of the second internal heat exchanger 19'. When the first shut-off valve 33 is arranged upstream of the second internal heat exchanger 19', as shown in fig. 4, the connection is made through a fifth connection point 71 arranged between the first shut-off valve 33 and the first connection point 33.

On the other hand, the branch conduit 70 is connected to the second bypass conduit 40 between the third expansion device 17 and the second shut-off valve 73, upstream of the third expansion device 17. The second shut-off valve 73 is arranged between the third connection point 41 and the third expansion device 17. The connection of the branch conduit 70 is made at a fifth connection point 72 arranged downstream of the second shut-off valve 73. The branch conduit 70 includes a third shut-off valve 74 to allow or disallow refrigerant fluid to pass therethrough.

The second heat transfer circuit B may in turn comprise:

the first two-fluid heat exchanger (5),

a first heat transfer fluid flow duct 50, which comprises a third heat exchanger 54 for being passed through by an internal air flow 100 of the motor vehicle, and connects a first junction 61 arranged downstream of the first dual-fluid heat exchanger 5 with a second junction 62 arranged upstream of said first dual-fluid heat exchanger 5,

a second heat transfer fluid flow duct 60 comprising a fourth heat exchanger 64 for passing an external air flow 200 of the motor vehicle and connecting a first junction 61 arranged downstream of the first dual fluid heat exchanger 5 with a second junction 62 arranged upstream of said first dual fluid heat exchanger 5, and

a pump 18, arranged downstream or upstream of the first dual fluid heat exchanger 5, between the first junction point 61 and the second junction point 62.

The indirectly reversible air-conditioning circuit 1 comprises, within the second heat transfer fluid circuit B, redirecting means for redirecting the heat transfer fluid originating from the first dual fluid heat exchanger 5 towards the first flow duct 50 and/or towards the second flow duct 60.

As shown in fig. 1 to 4, said redirection means for the heat transfer fluid originating from the first dual fluid heat exchanger 5 may in particular comprise a fourth shut-off valve 63 arranged on the second flow duct 60 to block or unblock the heat transfer fluid and prevent it from flowing in said second flow duct 60.

Indirect reversible air conditioning circuit 1 may also include a choke 310 for blocking the flow of internal air 100 through third heat exchanger 54.

In particular, this embodiment makes it possible to limit the number of valves on the second heat transfer fluid circuit B, and therefore to limit the production costs.

According to an alternative embodiment shown in fig. 6, the redirection means of the heat transfer fluid originating from the first dual fluid heat exchanger 5 may comprise in particular:

a fourth shut-off valve 63 arranged on the second flow duct 60 to block or unblock the heat transfer fluid and prevent it from flowing in said second flow duct 60, an

A fifth shut-off valve 53 arranged on the first flow duct 50 so as to block or unblock the heat transfer fluid and prevent it from flowing in said first flow duct 50.

The second heat transfer fluid circuit B may also comprise an electric heating element 55 of the heat transfer fluid. The electric heating element 55 is arranged in particular downstream of the first dual-fluid heat exchanger 5 in the flow direction of the heat transfer fluid, between the first dual-fluid heat exchanger 5 and the first junction point 61.

The present invention also relates to an operating method for operating the indirect reversible air conditioning circuit 1 according to the different operating modes illustrated in figures 7a to 12. In these fig. 7a to 12, only the elements in which the refrigerant fluid and/or the heat transfer fluid flow are shown. The direction of flow of the refrigerant fluid and/or the heat transfer fluid is indicated by arrows.

Fig. 7a and 7b depict a cooling mode in which:

the refrigerant fluid flows into the compressor 3, where it is brought to a high pressure, and flows in sequence into the first two-fluid heat exchanger 5, the first internal heat exchanger 19, the second internal heat exchanger 19', the first expansion device 7, where it is brought to a low pressure 7, said low pressure refrigerant fluid then flows in sequence into the first heat exchanger 9, the first bypass conduit 30, where it enters the second internal heat exchanger 19', then the first internal heat exchanger 19, then back to the compressor 3,

the heat transfer fluid at the outlet of the first dual fluid heat exchanger 5 flows into the fourth heat exchanger 64 of the second flow conduit 60.

Fig. 7a shows this cooling mode when the indirect reversible air-conditioning circuit 1 is according to the first embodiment of fig. 1. However, when the indirect reversible air-conditioning circuit 1 is according to the second embodiment of fig. 2 or the third embodiment of fig. 3, the flow of refrigerant fluid is the same except for the position of the fourth connection point 42.

Fig. 7b then depicts this cooling mode when the indirect reversible air-conditioning circuit 1 is according to the fourth embodiment of fig. 4.

As shown in fig. 7a and 7b, a portion of the heat transfer fluid at the outlet of the first dual fluid heat exchanger 5 flows into the third heat exchanger 54 of the first flow duct 50, and another portion of the heat transfer fluid at the outlet of the first dual fluid heat exchanger 5 flows into the fourth heat exchanger 64 of the second flow duct 60. The choke 310 is closed to prevent the flow of the internal air 100 into the third heat exchanger 54.

The refrigerant fluid at the inlet of the compressor 3 is in the gaseous phase. The refrigerant fluid is compressed by entering the compressor 3. The refrigerant fluid is then said to be at a high pressure.

The high pressure refrigerant fluid passes through the first dual fluid heat exchanger 5 and experiences enthalpy loss as it enters the liquid phase and transfers enthalpy to the heat transfer fluid of the second heat transfer fluid circuit B. The high pressure refrigerant fluid then loses enthalpy while maintaining a constant pressure.

The high pressure refrigerant fluid then enters the first internal heat exchanger 19 before losing enthalpy. This enthalpy is transferred from the first bypass line 30 to the low pressure refrigerant fluid.

The high pressure refrigerant fluid then enters the second internal heat exchanger 19', where it again loses enthalpy. This enthalpy is transferred to the low pressure refrigerant fluid passing through the first bypass line 30.

As shown in fig. 7a, at the outlet of the second interior heat exchanger 19', since the third expansion device 17 is closed, the refrigerant fluid does not flow into the second bypass pipe 40.

As shown in fig. 7b, if the indirect reversible air conditioning circuit 1 is according to the fourth embodiment, the refrigerant fluid does not flow into the second bypass duct 40 since the second shut-off valve 73 is closed.

The high pressure refrigerant fluid then enters the first expansion device 7. The high pressure refrigerant fluid undergoes an isenthalpic pressure loss and enters a two-phase mixed state. The refrigerant fluid is now said to be at a low pressure.

The low pressure refrigerant fluid then enters the first heat exchanger 9 where it gains enthalpy by cooling the internal air flow 100. The refrigerant fluid returns to the gaseous state. At the outlet of the first heat exchanger 9, the refrigerant fluid is redirected towards a first bypass duct 30. In order to prevent refrigerant fluid from entering the second heat exchanger 13, the second expansion device 11 is closed.

As shown in fig. 7b, if the branch pipe 70 is present, the refrigerant fluid does not pass through the branch pipe 70 since the third shut-off valve 74 is closed.

The low pressure refrigerant fluid then enters the second interior heat exchanger 19', where it obtains enthalpy from the high pressure refrigerant fluid passing through the second interior heat exchanger 19'.

The low pressure refrigerant fluid then enters the first interior heat exchanger 19 where it again obtains enthalpy from the high pressure refrigerant fluid passing through the first interior heat exchanger 19. The low pressure refrigerant fluid then returns to the compressor 3.

This cooling mode is useful for cooling the inner bore airflow 100.

In this cooling mode, the two internal heat exchangers 19 and 19' are active and their roles are additive. The internal heat exchangers 19 and 19' are used one after the other so that the enthalpy of the refrigerant fluid at the inlet of the first expansion device 7 can be reduced. The refrigerant fluid in the liquid state at the outlet of the first two-fluid heat exchanger 5 is cooled by the gaseous refrigerant fluid at low pressure leaving the first heat exchanger 9. The enthalpy difference at the terminal ends of the first heat exchanger 9 is significantly increased, which allows to increase the cooling capacity available at said first heat exchanger 9 of the cooling air flow 100, which consequently results in an increase of the coefficient of performance (or COP).

In addition, the addition of enthalpy to the low-pressure refrigerant fluid at the first internal heat exchanger 19 and the second internal heat exchanger 19' makes it possible to limit the proportion of refrigerant fluid that is in the liquid phase before it enters the compressor 3, in particular when the air-conditioning circuit 1 comprises a desiccant cylinder 14 arranged downstream of the first dual-fluid heat exchanger 5.

At the second heat transfer fluid circuit B, the heat transfer fluid obtains enthalpy from the refrigerant fluid at the first dual fluid heat exchanger 5.

As shown in fig. 7a and 7b, a portion of the heat transfer fluid flows into the first flow conduit 50 and through the third heat exchanger 54. However, the heat transfer fluid does not lose enthalpy because the obstructions 310 are closed and block the internal airflow 100 such that the heat transfer fluid does not pass through the third heat exchanger 54.

Another portion of the heat transfer fluid flows into the second flow conduit 60 and through the fourth heat exchanger 64. The heat transfer fluid loses enthalpy at the heat exchanger 64 by releasing enthalpy into the outside air stream 200. The fourth shutoff valve 63 is opened to allow the heat transfer fluid to pass therethrough.

In order to not send the heat transfer fluid in exchange with the internal air flow 100 at the third heat exchanger 54, an alternative solution (not shown) provides the first flow duct 50 with a fifth shut-off valve 53 and closes it to prevent the heat transfer fluid from flowing into said first flow duct 50, as shown in fig. 6.

Fig. 8a and 8b depict a parallel secondary cooling mode, wherein:

the refrigerant fluid flows into the compressor 3 where it enters at high pressure and flows in turn into the first dual fluid heat exchanger 5, the first internal heat exchanger 19 and the second internal heat exchanger 19':

a first portion of the refrigerant fluid enters the second bypass line 40, enters the third expansion device 17, where it enters a low pressure, then it flows into the second dual fluid heat exchanger 15, then merges with the low pressure refrigerant fluid from the first heat exchanger 9 upstream of the first internal heat exchanger 19,

a second portion of the refrigerant fluid enters the first expansion device 7, where it turns to low pressure, and then it flows successively into the first heat exchanger 9, into the first bypass conduit 30, into the second internal heat exchanger 19' at this first bypass conduit 30, then into the first internal heat exchanger 19, and then back to the compressor 3,

the heat transfer fluid at the outlet of the first two-fluid heat exchanger 5 flows into the fourth heat exchanger 64 of the second flow duct 50.

As shown in fig. 8a to 8c, a part of the heat transfer fluid at the outlet of the first two-fluid heat exchanger 5 flows into the third heat exchanger 54 of the first flow duct 50, and another part of the heat transfer fluid at the outlet of the first two-fluid heat exchanger 5 flows into the fourth heat exchanger 64 of the second flow duct 50. The choke 310 is closed to prevent the flow of the internal air 100 into the third heat exchanger 54.

Fig. 8a and 8b depict parallel secondary cooling modes when the indirect reversible air-conditioning circuit 1 is according to the first embodiment of fig. 1 and the second embodiment of fig. 2, respectively.

In both embodiments, the refrigerant fluid at the inlet of the compressor 3 is in the gaseous phase. The refrigerant fluid is compressed by entering the compressor 3. The refrigerant fluid is then said to be at high pressure at the outlet of the compressor 3.

The high pressure refrigerant fluid then enters the first internal heat exchanger 19 where it loses enthalpy. This enthalpy is transferred from the first bypass line 30 to the low pressure refrigerant fluid.

At the outlet of the second internal heat exchanger 19', as shown in fig. 8a and 8b, a first portion of the heat transfer fluid enters the second bypass duct 40 and a second portion of the refrigerant fluid is directed towards the first expansion device 7.

The low pressure refrigerant fluid then enters the second dual fluid heat exchanger 15 where it gains enthalpy by cooling the heat transfer fluid flowing in the secondary thermal management loop. The refrigerant fluid returns to the gaseous state. At the outlet of the second dual fluid heat exchanger 15, the refrigerant fluid merges with a first bypass conduit 30. In the first embodiment shown in fig. 8a, the refrigerant fluid merges with the first bypass conduit 30 upstream of the first shut-off valve 33 and of the second internal heat exchanger 19'. In the second embodiment shown in fig. 8b, the refrigerant fluid merges with the first bypass conduit 30 downstream of the first shut-off valve 33 and upstream of the second internal heat exchanger 19'.

A second portion of the high pressure refrigerant fluid enters the first expansion device 7. The high pressure refrigerant fluid undergoes an isenthalpic pressure loss and enters a two-phase mixed state. The refrigerant fluid is now said to be at a low pressure.

The low pressure refrigerant fluid from both the first heat exchanger 9 and the second bypass line 40 then enters the second interior heat exchanger 19 'where it obtains enthalpy from the high pressure refrigerant fluid passing through the second interior heat exchanger 19'.

This cooling mode is useful for cooling the internal airflow 100 and for cooling the heat transfer fluid of the secondary thermal management loop to cool components such as batteries and/or electronic components.

In this parallel secondary cooling mode for the first and second embodiments, both internal heat exchangers 19 and 19' act on both the refrigerant flow from the first heat exchanger 9 and the refrigerant flow through the second bypass line 40, and their effects are additive. The internal heat exchangers 19 and 19' are used one after the other so that the enthalpy of the refrigerant fluid at the inlet of the first expansion device 7 can be reduced. The refrigerant fluid in the liquid state at the outlet of the first two-fluid heat exchanger 5 is cooled by the gaseous refrigerant fluid at low pressure leaving the first heat exchanger 9 and the second two-fluid heat exchanger 15. The enthalpy difference at the terminals of the two heat exchangers is significantly increased, which allows to increase the cooling capacity available at both the first heat exchanger and said second two-fluid heat exchanger 15, which consequently results in an increase of the coefficient of performance (or COP).

Fig. 8c and 8d depict parallel secondary cooling modes when the indirect reversible air-conditioning circuit 1 is according to the third embodiment of fig. 3 and the fourth embodiment of fig. 4, respectively.

At the outlet of the second internal heat exchanger 19', as shown in fig. 8c and 8d, a first portion of the heat transfer fluid enters the second bypass duct 40 and a second portion of the refrigerant fluid is directed towards the first expansion device 7. According to the fourth embodiment shown in fig. 8d, since the second shut-off valve 73 is open, a first portion of the refrigerant fluid may enter the second bypass duct 40.

A first portion of the refrigerant fluid enters the third expansion device 17. The high pressure refrigerant fluid undergoes an isenthalpic pressure loss and enters a two-phase mixed state. The refrigerant fluid is now said to be at a low pressure. According to the fourth embodiment shown in fig. 8d, since the third shut-off valve 74 is closed, the first part of the refrigerant fluid does not enter the branch pipe 70.

The low pressure refrigerant fluid from the first heat exchanger 9 then enters the second interior heat exchanger 19', where the low pressure refrigerant fluid obtains enthalpy from the high pressure refrigerant fluid passing through the second interior heat exchanger 19'.

The low pressure refrigerant fluid from both the first heat exchanger 9 and the second bypass line 40 then enters the first interior heat exchanger 19 where it obtains enthalpy from the high pressure refrigerant fluid passing through the first interior heat exchanger 19. The low pressure refrigerant fluid then returns to the compressor 3.

In this parallel secondary cooling mode, the two internal heat exchangers 19 and 19' only act on the refrigerant fluid coming from the first heat exchanger 9, and their action is additive. The internal heat exchangers 19 and 19' are used one after the other so that the enthalpy of the refrigerant fluid at the inlet of the first expansion device 7 can be reduced. The refrigerant fluid in the liquid state at the outlet of the first two-fluid heat exchanger 5 is cooled by the gaseous refrigerant fluid at low pressure leaving the first heat exchanger 9. The enthalpy difference at the terminals of the first heat exchanger 9 is significantly increased, which allows to increase the cooling capacity available at said first heat exchanger 9, which consequently results in an increase of the coefficient of performance (or COP).

At the second heat transfer fluid circuit B, the heat transfer fluid obtains enthalpy from the refrigerant fluid at the first dual fluid heat exchanger 5.

As shown in fig. 8a and 8d, a portion of the heat transfer fluid flows into the first flow conduit 50 and through the third heat exchanger 54. However, the heat transfer fluid does not lose enthalpy because the obstructions 310 are closed and block the internal airflow 100 such that the heat transfer fluid does not pass through the third heat exchanger 54.

Fig. 9a and 9c depict a severe secondary cooling mode, wherein:

the refrigerant fluid flows into the compressor 3, where it becomes high pressure and flows in sequence into the first dual fluid heat exchanger 5, the first internal heat exchanger 19, the second internal heat exchanger 19', then the refrigerant fluid enters the second bypass conduit 40, enters the third expansion device 17, where it becomes low pressure, where it then flows into the second dual fluid heat exchanger 15,

the heat transfer fluid at the outlet of the first two-fluid heat exchanger 5 flows into the fourth heat exchanger 64 of the second flow duct 50.

Fig. 9a depicts this strict secondary cooling mode for the first embodiment of fig. 1. Fig. 9b depicts this strict secondary cooling mode for the second embodiment of fig. 2. Fig. 9c depicts this strict secondary cooling mode for the third embodiment of fig. 3. Fig. 9d depicts such a strict secondary cooling mode for the fourth embodiment of fig. 4.

This strict secondary cooling mode is the same as the parallel secondary cooling mode described above, except that the high pressure refrigerant fluid at the outlet of the second heat exchanger 19' flows only in the second bypass conduit 40 and does not pass through the first heat exchanger 9. For this purpose, the first expansion device 7 is closed.

Thus, this strict secondary cooling mode is very useful when it is only desired to cool the heat transfer fluid flowing in the secondary thermal management loop.

Fig. 10a and 10b depict a heat pump mode in which:

the refrigerant fluid flows into the compressor 3 where it becomes high pressure and flows sequentially into the first dual fluid heat exchanger 5, the first internal heat exchanger 19, the second internal heat exchanger 19', the first expansion device 7 where it becomes medium pressure, the medium pressure refrigerant fluid then flows sequentially into the first heat exchanger 9, the second expansion device 11 where it becomes low pressure, then into the second heat exchanger 13, then into the first internal heat exchanger 19, then back into the compressor 3,

the heat transfer fluid at the outlet of the first two-fluid heat exchanger 5 flows only into the third heat exchanger 54 of the first flow duct 50.

Medium pressure is understood here to mean the pressure between the low pressure of the refrigerant fluid when it enters the compressor 3 and the high pressure of the refrigerant fluid at the outlet of said compressor 3.

The high pressure refrigerant fluid then enters the first internal heat exchanger 19 before losing enthalpy. This enthalpy is transferred to the low pressure refrigerant fluid originating from the second heat exchanger 13.

The high pressure refrigerant fluid then enters the second interior heat exchanger 19 'where it does not lose enthalpy because no refrigerant fluid flows into the second interior heat exchanger 19'.

As shown in fig. 10a, at the outlet of the second interior heat exchanger 19', since the third expansion device 17 is closed, the refrigerant fluid does not flow into the second bypass pipe 40.

As shown in fig. 10b, if the indirect reversible air conditioning circuit 1 is according to the fourth embodiment, the refrigerant fluid does not flow into the second bypass duct 40 since the second shut-off valve 73 is closed.

The high pressure refrigerant fluid then enters the first expansion device 7. The refrigerant fluid experiences a first isenthalpic pressure loss, which brings the refrigerant fluid into a two-phase mixed state. The refrigerant fluid is now at an intermediate pressure.

The refrigerant fluid then passes through the first heat exchanger 9 where it loses enthalpy by heating the internal air flow 100.

At the outlet of the first heat exchanger 9, the refrigerant fluid is redirected towards the second heat exchanger 13. For this purpose, the first shut-off valve 33 of the first bypass is closed. Before reaching the second heat exchanger 13, the refrigerant fluid enters the first expansion device 11, where it undergoes a second isenthalpic pressure loss. The refrigerant fluid is now at a low pressure.

As shown in fig. 10b, if the branch pipe 70 is present, the medium pressure refrigerant fluid does not pass through the branch pipe 70 since the third shut-off valve 74 is closed.

In this heat pump mode, only the first internal heat exchanger 19 is active. Since the enthalpy of the low pressure refrigerant fluid at the inlet of the compressor 3 is greater, the enthalpy of the high pressure refrigerant fluid at the outlet of the compressor 3 will also be greater than the enthalpy of the refrigerant fluid when there is no internal heat exchanger.

In addition, the addition of enthalpy to the low-pressure refrigerant fluid at the first internal heat exchanger 19 makes it possible to limit the proportion of refrigerant fluid that is in the liquid phase before it enters the compressor 3, in particular when the air-conditioning circuit 1 comprises a desiccant cylinder 14 arranged downstream of the first dual-fluid heat exchanger 5. Since the length of the first internal heat exchanger 19 is in the range of 50 to 120mm, its effect is limited. This dimension makes it possible to limit the heat exchange between the high pressure refrigerant fluid and the low pressure refrigerant fluid, and therefore the enthalpy of exchange makes it possible to limit the proportion of refrigerant fluid in the liquid phase before entering the compressor 3, without compromising the efficiency of the heat pump mode. In fact, the purpose of this heat pump mode is to release as much enthalpy as possible into the internal air flow 100 in order to heat it at the first heat exchanger 9. In the heat pump mode, the enthalpy comes from the outside air flow 200 via the second heat exchanger 13.

At the second heat transfer fluid circuit B, the heat transfer fluid obtains enthalpy from the refrigerant fluid at the first dual fluid heat exchanger 5.

As shown in fig. 10a and 10b, the heat transfer fluid flows into the first flow conduit 50 and through the third heat exchanger 54. The heat transfer fluid loses enthalpy when heating the internal air flow 100. For this purpose, the damper door 310 is opened and/or the fifth shut-off valve 53 is opened. The fourth shut-off valve 63 is closed to prevent the heat transfer fluid from entering the second flow duct 60.

This heat pump mode is useful for heating the internal air stream 100 at both the first heat exchanger 9 and the third heat exchanger 54 by absorbing the enthalpy of the external air stream 200 of the second heat exchanger 13.

Additionally, the electrical heating element 55 may be in operation to provide an additional supply of thermal energy to the heat transfer fluid to heat the internal air flow 100.

11 a-11 c depict a parallel secondary heat pump mode, wherein:

a first portion of the refrigerant fluid passes through the second bypass line 40 by passing through the third expansion device 17 where, in the third expansion device 17, the refrigerant fluid enters a low pressure, passes through the second dual fluid heat exchanger 15, and then joins the refrigerant fluid from the second heat exchanger upstream of the first internal heat exchanger 19,

a second portion of the refrigerant fluid passes through the first expansion device 7 where the refrigerant fluid becomes at an intermediate pressure, then the refrigerant fluid flows in sequence into the first heat exchanger 9, the second expansion device 11, where the refrigerant fluid becomes at a low pressure, then into the second heat exchanger 13,

the low-pressure refrigerant fluid then passes through a first internal heat exchanger (19) and then returns to the compressor (3),

the heat transfer fluid at the outlet of the first two-fluid heat exchanger (5) flows only into the third heat exchanger (54) of the first flow duct (50).

This parallel secondary heat pump mode is only possible if the medium pressure refrigerant fluid at the outlet of the first heat exchanger 9 does not pass through the first bypass conduit 30 but through the second expansion device 11 and the second heat exchanger 13. Therefore, it is only possible if the first shut-off valve 33 is closed. In addition, it is necessary to allow a portion of the high pressure refrigerant fluid to pass through the second bypass line 40 and join the low pressure refrigerant fluid from the second heat exchanger 13. However, this is not possible in the case of the first embodiment, in which the second connection point 42 of the first bypass duct 40 is located upstream of the first shut-off valve 33. Thus, only the second, third and fourth embodiments may achieve this parallel secondary heat pump mode.

Fig. 11a shows such a secondary heat pump mode when the indirect reversible air conditioning circuit 1 is according to the second embodiment of fig. 2.

Fig. 11b shows the secondary heat pump mode when the indirect reversible air-conditioning circuit 1 is according to the third embodiment of fig. 3.

Fig. 11c shows the secondary heat pump mode when the indirect reversible air-conditioning circuit 1 is according to the fourth embodiment of fig. 4.

The high pressure refrigerant fluid then enters the first internal heat exchanger 19 before losing enthalpy. The enthalpy is transferred to the low pressure refrigerant fluid originating from the second heat exchanger 13 and the second bypass line 40.

The high pressure refrigerant fluid then enters the second internal heat exchanger 19.

As shown in fig. 11a, when the indirect reversible air conditioning circuit 1 is an indirect reversible air conditioning circuit according to the second embodiment, because the second connection point 42 of the second bypass duct 40 is located on the first bypass duct 30 upstream of the second internal heat exchanger 19', the high pressure refrigerant fluid exchanges enthalpy with the low pressure refrigerant fluid from the second bypass duct 40.

As shown in fig. 11b and 11c, when the indirect reversible air conditioning circuit 1 is according to the third or fourth embodiment, since the second connection point 42 of the second bypass duct 40 is downstream of the second internal heat exchanger 19', the high pressure refrigerant fluid does not lose enthalpy because no refrigerant fluid flows into said second internal heat exchanger 19'.

A first portion of the refrigerant fluid enters the third expansion device 17. The high pressure refrigerant fluid undergoes an isenthalpic pressure loss and enters a two-phase mixed state. The refrigerant fluid is now said to be at a low pressure. When the indirect reversible air-conditioning circuit 1 is according to the fourth embodiment, the second shut-off valve 73 is open as shown in fig. 11 c.

According to a second embodiment, shown in fig. 11a, at the outlet of the second dual-fluid heat exchanger 15, the refrigerant fluid merges with the first bypass conduit 30 downstream of the first shut-off valve 33 and upstream of the second internal heat exchanger 19'. According to the third and fourth embodiments, the refrigerant fluid merges downstream of the second internal heat exchanger 19' with the first bypass conduit 30.

A second portion of the high pressure refrigerant fluid then enters the first expansion device 7. The refrigerant fluid experiences a first isenthalpic pressure loss, which brings the refrigerant fluid into a two-phase mixed state. The refrigerant fluid is now at an intermediate pressure.

The refrigerant fluid then passes through the first heat exchanger 9 where it loses enthalpy by heating the internal air flow 100.

At the outlet of the first heat exchanger 9, the refrigerant fluid is redirected towards the second heat exchanger 13. For this reason, the first shut valve 33 of the first bypass pipe 30 is closed. Before reaching the second heat exchanger 13, the refrigerant fluid enters the first expansion device 11, where it undergoes a second isenthalpic pressure loss. The refrigerant fluid is now at a low pressure.

As shown in fig. 11c, if the branch pipe 70 is present, the medium pressure refrigerant fluid does not pass through the branch pipe 70 since the third shut-off valve 74 is closed.

The low pressure refrigerant fluid then passes through the second heat exchanger 13 where it gains enthalpy by absorbing enthalpy from the outside air stream 200 in the second heat exchanger 9. The refrigerant fluid then returns to the gaseous state. At the outlet of the second heat exchanger 13, the refrigerant fluid is recombined by the refrigerant fluid having passed through the second bypass conduit 40.

In this parallel secondary heat pump mode, in the second embodiment, the first internal heat exchanger 19 and the second internal heat exchanger 19' are active.

For the third and fourth embodiments, only the first internal heat exchanger 19 is active. Since the enthalpy of the low pressure refrigerant fluid at the inlet of the compressor 3 is greater, the enthalpy of the high pressure refrigerant fluid at the outlet of the compressor 3 will also be greater than the enthalpy of the refrigerant fluid when there is no internal heat exchanger.

In addition, the addition of enthalpy to the low-pressure refrigerant fluid at the first internal heat exchanger 19 makes it possible to limit the proportion of refrigerant fluid that is in the liquid phase before it enters the compressor 3, in particular when the air-conditioning circuit 1 comprises a desiccant cylinder 14 arranged downstream of the first dual-fluid heat exchanger 5. Since the length of the first internal heat exchanger 19 is in the range of 50 to 120mm, its effect is limited. This dimension makes it possible to limit the heat exchange between the high pressure refrigerant fluid and the low pressure refrigerant fluid, and therefore the enthalpy of exchange makes it possible to limit the proportion of refrigerant fluid in the liquid phase before it enters the compressor 3, without compromising the efficiency of the parallel secondary heat pump mode. In fact, the purpose of this parallel secondary heat pump mode is to release as much enthalpy as possible into the internal air flow 100 in order to heat it at the first heat exchanger 9. In the parallel secondary heat pump mode, the enthalpy is from the outside air stream 200 via the second heat exchanger 13 and from the secondary thermal management circuit via the second dual fluid heat exchanger 15.

At the second heat transfer fluid circuit B, the heat transfer fluid obtains enthalpy from the refrigerant fluid at the first dual fluid heat exchanger 5.

As shown in fig. 11a to 11c, the heat transfer fluid flows into the first flow duct 50 and passes through the third heat exchanger 54. The heat transfer fluid loses enthalpy when heating the internal air flow 100. For this purpose, the damper door 310 is opened and/or the fifth shut-off valve 53 is opened. The fourth shut-off valve 63 is closed to prevent the heat transfer fluid from entering the second flow duct 60.

This parallel secondary heat pump mode is useful for heating the internal air stream 100 at both the first heat exchanger 9 and the third heat exchanger 54 by absorbing the enthalpy of the external air stream 200 at the second heat exchanger 13, and also absorbing the enthalpy of the secondary thermal management circuit at the second dual fluid heat exchanger 15.

Additionally, the electrical heating element 55 may be in operation to provide an additional supply of thermal energy to the heat transfer fluid to heat the internal air flow 100.

Preferably, for this parallel secondary heat pump mode, the first portion of the refrigerant fluid passing through the second bypass conduit 40 has a greater mass flow than the second portion of the refrigerant fluid passing through the first heat exchanger 9.

Fig. 12 depicts a strict secondary heat pump mode, wherein:

the refrigerant fluid flows into the compressor 3, where it is brought to a high pressure in the compressor 3 and flows in turn into the first two-fluid heat exchanger 5, the first internal heat exchanger 19, the second internal heat exchanger 19', the first expansion device 7, where the refrigerant fluid is brought to an intermediate pressure in the first expansion device 7, the refrigerant fluid then flows in turn into the first heat exchanger 9, the first bypass conduit 30, the branch conduit 70, the third expansion device 17, where the refrigerant fluid is brought to a low pressure in the third expansion device 17 and then flows into the second two-fluid heat exchanger 15, the low pressure refrigerant fluid then passes through the first internal heat exchanger 19 and then returns to the compressor 3,

the heat transfer fluid at the outlet of the first two-fluid heat exchanger 5 flows only into the third heat exchanger 54 of the first flow duct 50.

The high pressure refrigerant fluid then enters the second interior heat exchanger 19', where the refrigerant fluid does not lose enthalpy because the second connection point 42 of the second bypass tube 40 is downstream of the second interior heat exchanger 19', and no refrigerant fluid flows into the second interior heat exchanger 19 '.

The high pressure refrigerant fluid enters the first expansion device 7. The refrigerant fluid experiences a first isenthalpic pressure loss, which brings the refrigerant fluid into a two-phase mixed state. The refrigerant fluid is now at an intermediate pressure. Since the second shut-off valve 73 is closed, the high-pressure refrigerant fluid does not enter the second bypass duct 40 at the outlet of the second interior heat exchanger 19'.

The refrigerant fluid then passes through the first heat exchanger 9 where it loses enthalpy by heating the internal air flow 100.

At the outlet of the first heat exchanger 9, the medium-pressure refrigerant fluid is redirected towards the branch conduit 70. For this purpose, the first shut-off valve 33 of the first bypass conduit 30 and the second expansion device 11 are closed. The third stop valve 74 is opened again.

The medium pressure refrigerant fluid then enters the third expansion device 17. The refrigerant fluid then undergoes a second isenthalpic pressure loss. The refrigerant fluid is now said to be at a low pressure.

In this strict secondary heat pump mode, only the first internal heat exchanger 19 is active. Since the enthalpy of the low pressure refrigerant fluid at the inlet of the compressor 3 is greater, the enthalpy of the high pressure refrigerant fluid at the outlet of the compressor 3 will also be greater than the enthalpy of the refrigerant fluid when there is no internal heat exchanger.

In addition, the addition of enthalpy to the low-pressure refrigerant fluid at the first internal heat exchanger 19 makes it possible to limit the proportion of refrigerant fluid in the liquid phase before it enters the compressor 3, in particular when the air-conditioning circuit 1 comprises a desiccant cylinder 14 arranged downstream of the first dual-fluid heat exchanger 5. Since the length of the first internal heat exchanger 19 is in the range of 50 to 120mm, its effect is limited. This dimension makes it possible to limit the heat exchange between the high pressure refrigerant fluid and the low pressure refrigerant fluid, and therefore the enthalpy of exchange makes it possible to limit the proportion of refrigerant fluid in the liquid phase before it enters the compressor 3, without compromising the efficiency of the strict secondary heat pump mode. In fact, the purpose of this strict secondary heat pump mode is to release as much enthalpy as possible into the internal air flow 100 in order to heat it at the first heat exchanger 9. In this severe secondary heat pump mode, the enthalpy comes from the secondary thermal management loop through the second dual fluid heat exchanger 15.

At the second heat transfer fluid circuit B, the heat transfer fluid obtains enthalpy from the refrigerant fluid at the first dual fluid heat exchanger 5.

As shown in fig. 12, the heat transfer fluid flows into the first flow duct 50 and passes through the third heat exchanger 54. The heat transfer fluid loses enthalpy when heating the internal air flow 100. For this purpose, the damper door 310 is opened and/or the fifth shut-off valve 53 is opened. The fourth shut-off valve 63 is closed to prevent the heat transfer fluid from entering the second flow duct 60.

This strict secondary heat pump mode is useful for heating the internal air stream 100 at both the first heat exchanger 9 and the third heat exchanger 54 by absorbing enthalpy from the external air stream 200 at the second heat exchanger 15.

Additionally, the electrical heating element 55 may be in operation to provide an additional supply of thermal energy to the heat transfer fluid to heat the internal air flow 100.

This architecture of the indirect reversible air conditioning circuit 1 is also envisaged for other modes of operation, such as defrosting, drying or heating modes.

It is therefore evident that, by virtue of its architecture and the presence of the two internal heat exchangers 19 and 19', the air-conditioning circuit 1 allows to operate in a cooling mode with improved cooling performance and COP, and in a heat pump mode, in which its efficiency is hardly reduced by the action of the internal heat exchangers. In addition, the presence of the second bypass circuit 40 makes it possible to cool elements such as batteries and/or electronic components present in the secondary thermal management circuit not only during various cooling modes but also during a heat pump mode in which the thermal energy released by the secondary thermal management circuit makes it possible to heat the internal air flow 100, thus contributing to heating the interior of the car.

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Indirect reversible air-conditioning circuit for a motor vehicle and corresponding operating method

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