CN109416206B

CN109416206B - Refrigerant circuit designed for thermal control of an energy source

Info

Publication number: CN109416206B
Application number: CN201780042929.2A
Authority: CN
Inventors: M.雅希亚; L.克莱马隆; R.哈勒; J-L.图茨; B.尼克拉斯; J-M.刘
Original assignee: Valeo Systemes Thermiques SAS
Current assignee: Valeo Systemes Thermiques SAS
Priority date: 2016-05-19
Filing date: 2017-04-07
Publication date: 2021-12-17
Anticipated expiration: 2037-04-07
Also published as: CN109416206A; FR3051546A1; WO2017198919A1; EP3458783A1

Abstract

The invention relates to a refrigerant circuit (19) in which a refrigerant can flow, the refrigerant circuit (1) comprising at least one first heat exchanger (6) and at least one second heat exchanger (9), characterized in that the refrigerant circuit (1) comprises a first branch (13) provided with a first expansion device (2), the first branch (13) comprising a branch point (16) common to the second branch (14) and the third branch (15), the second branch (14) is provided with a second expansion device (3) and a first heat exchanger (6), the second expansion means (3) being interposed between the branch point (16) and the first heat exchanger (6), the third branch (15) being provided with a second heat exchanger (9) and a first expansion member (12), the second heat exchanger (9) is interposed between the branch point (16) and the first expansion member (12). The invention can be applied to motor vehicles.

Description

Refrigerant circuit designed for thermal control of an energy source

Technical Field

The technical field of the invention is that of heating, ventilation and/or air-conditioning installations, in particular for the interior of motor vehicles. The object of the invention is a refrigerant circuit comprising a first heat exchanger and connected to a heat transfer liquid circuit by a second heat exchanger.

Background

Motor vehicles are generally equipped with a refrigerant circuit for varying the temperature of the air contained within the interior of the motor vehicle. Document US 2015/0121939 discloses a refrigerant circuit, in particular of the above type, comprising an accumulator downstream of two parallel circuit portions, comprising a first portion having a first valve, a first expansion device and a first heat exchanger; and a second section having a second valve, a second expansion device, and a second heat exchanger. In the operating mode, in which the first and second valves are opened simultaneously, the management of the mass flow in the first and second portions is irregular, which is unsatisfactory.

In fact, it is desirable to be able to control the pressure of the refrigerant in the first heat exchanger and in the second heat exchanger independently, the control of the refrigerant circuit of document US 2015/0121939 not being allowed.

Disclosure of Invention

The object of the present invention is to propose a refrigerant circuit which offers a satisfactory solution to the above-mentioned problems.

The object of the invention is a refrigerant circuit in which a refrigerant circulates, comprising at least one heat exchanger arranged to thermally treat a first air flow, and at least one second heat exchanger arranged to exchange heat with a heat transfer liquid circulating within a heat transfer liquid circuit comprising an energy source.

According to the invention, the refrigerant circuit through which the refrigerant can flow comprises at least one first heat exchanger and at least one second heat exchanger, characterized in that the refrigerant circuit comprises a first branch provided with a first expansion device, said first branch comprising a branch point common to a second branch provided with a second expansion device interposed between the branch point and the first heat exchanger and a third branch provided with a second heat exchanger interposed between the branch point and the first expansion member and a first expansion member.

Advantageously, the refrigerant circuit comprises at least one of the following features, alone or in combination:

the second expansion means comprise a second expansion member having a constant cross section;

the second expansion means comprise a first valve for controlling the refrigerant circulation in the second branch, said valve being interposed between the branch point and the second expansion member. Such first control valves are, for example, sealing valves, in particular proportional or switching valves;

the first expansion member is a valve for regulating the refrigerant flow;

the refrigerant circuit is advantageously provided with an accumulator;

-the accumulator is interposed between the first heat exchanger and a connection point common to the second branch and to the third branch;

alternatively, the accumulator is arranged downstream of the connection point common to the second branch and the third branch, in the direction of circulation of the refrigerant in the refrigerant circuit;

-the first heat exchanger is arranged to thermally treat the first air stream and the second heat exchanger is arranged to exchange heat with a heat transfer liquid circulating within a heat transfer liquid circuit comprising an energy source;

the third branch is provided with the first channel of the second heat exchanger.

The invention also relates to a thermodynamic circuit in which a refrigerant circulates. Such a thermodynamic circuit includes the refrigerant return described in this document.

Advantageously, the thermodynamic circuit comprises, alone or in combination, at least one of the following features:

the first flow line comprises successively a compressor, a first junction point, a second control valve, a second junction point, a third heat exchanger, a third junction point, a first check valve, a fourth junction point, a first passage of the fourth heat exchanger, a fifth junction point, a second check valve, a sixth junction point, a first branch, a branch point, a second branch, a connection point common to the second branch and the third branch, a third control valve, a seventh junction point and a second passage of the fourth heat exchanger for returning to the compressor;

-a second refrigerant flow line extending between the first junction point and the sixth junction point, the second flow line successively comprising a fifth heat exchanger and a fourth control valve from the first junction point towards the sixth junction point;

-a third refrigerant flow-through line extending between the second junction point and the seventh junction point and including a fifth control valve;

-a fourth flow-through line extending between the connection point and the fifth junction and comprising a third check valve;

-a fifth flow-through line extending between the third junction point and the fourth junction point and comprising a third expansion member.

It is another object of the present invention to provide an assembly formed by the thermodynamic circuit and the heat transfer liquid circuit described in this document, wherein the heat transfer liquid circuit comprises a first pipe with a pump, a second passage of a second heat exchanger and a three-way valve distributing the heat transfer liquid towards the second pipe or towards a third pipe, the second pipe being a pipe for bypassing the third pipe, the third pipe being arranged to exchange heat with an energy source.

Another object of the invention is a method for implementing such an assembly, wherein the compressor is operated so as to deliver refrigerant at high pressure.

Advantageously, the method is implemented by a plurality of operating modes comprising:

-a first mode, wherein the first expansion device allows expansion, the first expansion member is closed, the first control valve is open, the second control valve is open, the third control valve is open, the fourth control valve is closed, the fifth control valve is closed, the first check valve is open, the second check valve is open, the third check valve is closed, and the pump is stopped;

-a second mode, wherein the first expansion device allows expansion, the first expansion member is open, the first control valve is open, the second control valve is open, the third control valve is open, the fourth control valve is closed, the fifth control valve is closed, the first check valve is open, the second check valve is open, the third check valve is closed, and the pump is operating;

-a third mode, wherein the first expansion device allows expansion, the first expansion member is closed, the first control valve is open, the second control valve is open, the third control valve is open, the fourth control valve is open, the fifth control valve is closed, the first check valve is open, the second check valve is open, the third check valve is closed, and the pump is stopped;

-a fourth mode, wherein the first expansion device allows expansion, the first expansion member is closed, the first control valve is open, the second control valve is closed, the third control valve is closed, the fourth control valve is open, the fifth control valve is open, the first check valve is closed, the second check valve is closed, the third check valve is open, and the pump is stopped;

-a fifth mode, wherein the first expansion device allows expansion, the first expansion member is open, the first control valve is open, the second control valve is closed, the third control valve is closed, the fourth control valve is open, the fifth control valve is open, the first check valve is closed, the second check valve is closed, the third check valve is open, and the pump is operating;

-a sixth mode, wherein the first expansion device allows expansion, the first expansion member is open, the first control valve is closed, the second control valve is closed, the third control valve is open, the fourth control valve is open, the fifth control valve is closed, the first check valve is closed, the second check valve is closed, the third check valve is closed, and the pump is operated;

-a seventh mode, wherein the first expansion device allows expansion, the first expansion member is open, the first control valve is closed, the second control valve is open, the third control valve is open, the fourth control valve is open, the fifth control valve is closed, the first check valve is open, the second check valve is open, the third check valve is closed, and the pump is operated;

an eighth mode, wherein the first expansion device allows expansion, the first expansion member is open, the first control valve is closed, the second control valve is closed, the third control valve is closed, the fourth control valve is open, the fifth control valve is open, the first check valve is closed, the second check valve is closed, the third check valve is open, and the pump is operating.

Drawings

Other features, details and advantages of the invention will become more apparent upon reading the description, which is given by way of illustration below, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a refrigerant circuit of the present invention;

FIG. 2 is a schematic diagram of a variation of the refrigerant circuit shown in FIG. 1;

FIG. 3 is a schematic diagram of a thermodynamic circuit including the refrigerant circuit shown in FIG. 1 connected to a heat transfer liquid circuit;

FIG. 4 is a schematic diagram of a thermodynamic circuit including the refrigerant circuit shown in FIG. 2, also connected to a heat transfer liquid circuit;

FIG. 5 is a schematic diagram of the thermal power circuit of FIG. 3 in a first mode of operation, referred to as an air conditioning mode;

FIG. 6 is a schematic diagram of the thermodynamic circuit shown in FIG. 3 in a second mode of operation, referred to as an energy source air conditioning and cooling mode;

FIG. 7 is a schematic view of the thermodynamic circuit shown in FIG. 3 in a third mode of operation, referred to as an air conditioning and window defogging mode;

FIG. 8 is a schematic diagram of the thermodynamic circuit shown in FIG. 3 in a fourth mode of operation, referred to as the heat pump mode;

FIG. 9 is a schematic diagram of the thermodynamic circuit shown in FIG. 3 in a fifth mode of operation, referred to as an energy source heat pump and heating mode;

FIG. 10 is a schematic diagram of the thermodynamic circuit shown in FIG. 3 in a sixth mode of operation, referred to as an energy source heat pump and cooling mode;

FIG. 11 is a schematic diagram of the thermodynamic circuit shown in FIG. 3 in a seventh mode of operation, referred to as an energy source cooling mode;

FIG. 12 is a schematic diagram of the thermodynamic circuit shown in FIG. 3 in an eighth mode of operation, referred to as an energy source heating mode;

FIG. 13 is a Morill diagram illustrating thermal performance of the thermal circuit shown in FIG. 3 used in accordance with the second mode of operation shown in FIG. 6.

Detailed Description

Motor vehicles are generally equipped with a thermodynamic circuit for changing the temperature of the air contained within the interior of the motor vehicle.

According to the invention, the thermodynamic circuit comprises a refrigerant circuit 1, such as the one illustrated by way of example in fig. 1 and 2.

The thermodynamic circuit is a closed loop circuit within which refrigerant circulates. The refrigerant is, for example, a supercritical fluid, such as carbon dioxide, labeled as R-744. The refrigerant is even, for example, a supercritical fluid, such as a fluorine-containing refrigerant labeled R-134a, or a non-fluorine-containing refrigerant known as 1234 yf. Such a fluid may circulate within the refrigerant circuit 1 shown in fig. 1 and 2.

In general, the refrigerant circuit 1 is able to allow and/or prevent the circulation of refrigerant in at least one branch circuit comprised in the refrigerant circuit 1. The refrigerant circuit 1 is also capable of allowing at least one expansion, preferably two expansions, of the refrigerant within the refrigerant circuit 1, the two expansions being subsequent to each other within the refrigerant circuit 1, i.e. in series.

The refrigerant circuit 1 is also able to allow heat to be exchanged between the refrigerant and at least one air flow passing through the heat exchanger before said at least one air flow is distributed within the interior of the motor vehicle. The refrigerant circuit 1 is also able to allow heat to be exchanged between the refrigerant and a heat transfer liquid circulating within a heat transfer liquid circuit arranged to vary the temperature of at least one heat source. The refrigerant circuit 1 is also capable of individually regulating the pressure of the refrigerant in the heat exchangers contained in the refrigerant circuit 1.

To this end, as can be seen in fig. 1 and 2, the refrigerant circuit 1 comprises at least one first expansion device 2 for causing a first pressure drop in the refrigerant. The first expansion device 2 is preferably an expansion device with a pressure control loop. As an example, the first expansion means 2 is an opening with a variable cross-section, an electronic pressure reducing valve or the like.

The refrigerant circuit 1 comprises at least one second expansion device 3 for causing a second pressure drop in the refrigerant. The second expansion device 3 is preferably an expansion device without a pressure control loop. As an example, the second expansion means 3 optionally comprises a first control valve 101 able to allow or prevent the circulation of the refrigerant passing therethrough; and a second expansion member 5 without a control loop, such as an expansion member with a constant cross section, also called an opening with a fixed capillary cross section or similar. The second expansion member 5 is configured to generate a constant and predetermined pressure drop.

The refrigerant circuit 1 further comprises at least one first heat exchanger 6 arranged to allow a first exchange of heat between the refrigerant and a first air stream 7. The first air flow 7 is preferably an air flow circulating inside the housing of the heating, ventilation and/or air-conditioning installation 8, so as to be distributed inside the interior of the motor vehicle, in order to vary the temperature of the air contained inside the motor vehicle interior.

The refrigerant circuit 1 further comprises at least one second heat exchanger 9 arranged to allow a second exchange of heat between the refrigerant and the heat transfer liquid. The second heat exchanger 9 comprises, for example, a first passage 10 in which the refrigerant circulates and a second passage 11 in which the heat transfer liquid circulates, the first passage 10 and the second passage 11 being mutually arranged to promote the heat exchange between the refrigerant and the heat transfer liquid.

Finally, the refrigerant circuit 1 comprises at least one first expansion member 12, which is able to control the flow and/or expansion of the refrigerant passing through the second heat exchanger 9, and which is able to adapt the pressure at the outlet of the second heat exchanger 9 according to the pressure of the refrigerant at the inlet of the first heat exchanger, as described later. The first expansion member 12 is also able to control the heat exchange between the first and

second channels

10, 11 and in turn the temperature of the heat transfer fluid circulating within the second channel 11.

The components of the refrigerant circuit 1 are placed one with respect to the other according to a specific arrangement within the refrigerant circuit. More particularly, the refrigerant circuit 1 comprises a first branch 13, on which the first expansion device 2 is arranged. The first branch 13 is divided into a second branch 14 and a third branch 15. The second branch 14 comprises the second expansion device 3 and the first heat exchanger 6, the second expansion member 5 being interposed between the first control valve 101 and the first heat exchanger 6. The third branch 15 comprises the second heat exchanger 9 and the first expansion member 12. Even more particularly, the refrigerant circuit 1 comprises a branch point 16, at which the first branch 13 is divided into a second branch 14 and a third branch 15, and a connection point 17, at which the second branch 14 and the third branch 15 merge. From the branch point 16 up to the connection point 17, the second branch 14 comprises successively the first control valve 101, the second expansion member 5 and the first heat exchanger 6. From the branch point 16 up to the connection point 17, the third branch 15 comprises the second heat exchanger 9 and the first expansion means 12.

Regardless of the operating mode of the refrigerant circuit, the refrigerant passes through the first expansion device 2 and then flows from the branch point 16 up to the connection point 17. In other words, in the first circulation direction S of the refrigerant in the refrigerant circuit 1₁The branch point 16 is located upstream of the connection point 17.

These arrangements are such that, as the refrigerant flows within the refrigerant circuit 1, at least some of the refrigerant may undergo cascade-like expansion. Upstream of the first expansion device 2, the refrigerant is at a first pressure P₁. In the first expansion device 2, the refrigerant undergoes a first expansion, so that downstream of the first expansion device 2, the refrigerant is at a second pressure P₂The second pressure being lower than the first pressure P₁。

After having undergone a second expansion in the second expansion member 5, the refrigerant following the second branch 14 is at a third pressure P₃Third expansion pressure P₃At a second pressure P₂The following. Downstream of the first heat exchanger 6, the refrigerant is at a fourth pressure P₄。

Advantageously, it should be noted that the rotation speed of the compressor comprised in the thermodynamic circuit is controlled so as to supply the first heat exchanger 6 with a sufficient flow of refrigerant so as to deliver the first air flow 7 having the temperature requested by the user of the motor vehicle.

The refrigerant following the third branch 15 undergoes a flow rate change through the first expansion member 12. The refrigerant is thus at a fifth pressure P upstream of the second heat exchanger 9₅And a sixth pressure P at the outlet of the first expansion member 12₆。

Advantageously, it should be noted that the first expansion means 12 maintain the second heat exchanger 9 at the fifth pressure P₅For improved efficiency thereof, and the first expansion means 12 consolidates the second heat exchanger 9 at the fifth pressure P₅While compensating for the pressure drop achieved by the second expansion means 5. In other words, such an architecture allows to prevent the sixth pressure P₆Prevails in the second heat exchanger 9 and allows this sixth pressure P₆Is adjusted to a fourth pressure P₄。

According to the variant shown in fig. 2, in addition to the elements described above, the refrigerant circuit 1 comprises an accumulator 18 arranged on the second branch 14 between the first heat exchanger 6 and the connection point 17. In this case, the refrigerant is at a seventh pressure P at the outlet of the accumulator 18₇. Such an architecture allows the second heat exchanger 9 to be maintained at the fifth pressure P₅And allowing a sixth pressure P₆Is adjusted to a seventh pressure P₇. Such an architecture is advantageous if the first heat exchanger 6 is housed within the housing of the heating, ventilation and/or air bar installation 8, and if the thermodynamic circuit 19 comprises a heat exchanger housed in the front panel of the motor vehicle.

The refrigerant circuit 1 is advantageously adapted to the thermodynamic circuit 19 of the invention, as shown in fig. 3 to 12. Fig. 3 shows a thermodynamic circuit 19 of the invention including the refrigerant circuit 1 shown in fig. 1, while fig. 4 shows a thermodynamic circuit 19 of the invention including the refrigerant circuit 1 shown in fig. 2. Fig. 5 to 12 show various operating modes of the thermodynamic circuit 19, which can be applied to the refrigerant circuit 1 shown in fig. 1 or 2.

In fig. 3 and 4, in addition to the refrigerant circuit 1, the thermodynamic circuit 19 includes a compressor 20 for bringing the refrigerant to a high pressure HP. The thermodynamic circuit 19 also includes a third heat exchanger 21 arranged to allow heat exchange with a second airflow 22, such as an inside outside airflow. For this purpose, the third heat exchanger 21 is preferably arranged in the front panel of the motor vehicle. The thermodynamic circuit 19 includes a third expansion member 23 in which the refrigerant undergoes expansion. The thermodynamic circuit 19 includes a fourth heat exchanger 24 comprising a first passage 25 and a second passage 26 for refrigerant capable of exchanging heat with each other. The thermodynamic circuit 19 further comprises a fifth heat exchanger 27 arranged to exchange heat with the first air stream 7. This fifth heat exchanger 27 exchanges heat with the first air stream 7 after the heat exchange between the first heat exchanger 6 and the first air stream 7. In other words, the fifth heat exchanger 27 is preferably arranged downstream of the first heat exchanger 6 in the flow direction of the first air stream 7 within the housing of the heating, ventilation and/or air conditioning installation 8. The fifth heat exchanger 27 may be used as a heating radiator, and the first heat exchanger 6 may be used as an evaporator.

The thermal circuit 19 has a specific architecture for providing the various modes of operation, as described below. More particularly, the thermodynamic circuit 19 includes a plurality of

flow lines

28, 29, 30, 31, 32 that complete the third branch 15 through which refrigerant may or may not flow depending on the open or closed position of the

control valves

101, 102, 103, 104, 105 or

check valves

301, 302, 303 contained within the

flow lines

28, 29, 30, 31, 32 or the third branch 15. These flow-through

lines

28, 29, 30, 31, 32 and the third branch 15 are connected to each other by a branch point 16, a connection point 17,

junction points

201, 202, 203, 204, 205, 206, 207.

The thermodynamic circuit 19 includes a first flow line 28, the first flow line 28 successively including a compressor 20, a first junction point 201, a second control valve 102, a second junction point 202, a third heat exchanger 21, a third junction point 203, a first check valve 301 that allows refrigerant to pass only from the third junction point 203 toward a fourth junction point 204. The first flow-through line 28 then comprises, in succession, the first passage 25, the fifth junction point 205, the second check valve 302 which allows the refrigerant to pass only from the fifth junction point 205 towards the sixth junction point 206, which is joined to the first branch 13. The first flow-through line 28 then comprises successively the first expansion device 2, the branch point 16, the second branch 14 with the first control valve 101, the second expansion means 5, the first heat exchanger 6 and the connection point 17. The first flow-through line 28 then comprises, in succession, the third control valve 103, the seventh junction 207, the accumulator 18, the second passage 26 for return to the compressor 20.

The thermal circuit 19 also includes a second refrigerant flow line 29 extending between the first junction point 201 and a sixth junction point 206. From the first junction 201 towards the sixth junction 206, the second flow-through line 29 comprises successively the fifth heat exchanger 27 and the fourth control valve 104.

The thermal circuit 19 also includes a third refrigerant flow line 30 extending between the second junction point 202 and a seventh junction point 207 and including a fifth control valve 105.

The thermodynamic circuit 19 also includes a fourth flow line 31 extending between the connection point 17 and the fifth junction point 205 and including a third check valve 303, the check valve 303 allowing refrigerant to pass only from the connection point 17 toward the sixth junction point 206.

Finally, the thermal circuit 19 includes a fifth flow line 32 extending between the third junction 203 and the fourth junction 204 and including a fifth expansion member 23.

Furthermore, the second channel 11 of the second heat exchanger 9 is an integral part of the heat transfer liquid circuit 33. The heat transfer liquid is formed, for example, by a mixture of water and glycol, or the like. The heat transfer liquid circuit 33 includes a pump 34 for circulating the heat transfer liquid circuit 33. The pump 34 is mounted in a first conduit 35 contained in the heat transfer liquid circuit 33. The heat transfer liquid circuit 33 also comprises a three-way valve 36 which distributes the heat transfer liquid from the pump 34 towards a second conduit 37 or towards a third conduit 38. The third conduit 38 carries a heat transfer liquid for exchanging heat with a heat source 39, such as an electric heat source. According to the invention, the heat source may be formed by one or more batteries, and more particularly by a battery that powers an electric drive motor of the vehicle.

Alternatively, the energy source 39 may be a mechanical heat source or other element of the motor vehicle that must be provided with a heat treatment during its operation. As an extension, the energy source 39 may be formed by a specific element of the refrigerant circuit loop dedicated to the thermal control of a specific zone of the motor vehicle, in particular the rear zone or the like.

The second duct 37 forms a passage for bypassing the third duct 38. The second and

third conduits

37, 38 meet at an attachment point 40. Along a second flow direction S of the heat transfer liquid in the first conduit 35₂The attachment point 40 is arranged upstream of the second channel 11 and the pump 34.

In fig. 4, the thermodynamic circuit 19 incorporates the refrigerant circuit 1 according to the variant of fig. 2, the accumulator 18 shown in fig. 3 being positioned on the third branch 15 between the first expansion means 12 and the connection point 17.

As previously mentioned, the thermodynamic circuit 19 is able to operate in various modes, through different embodiments of the first branch 13 and/or of the second branch 14 of the refrigerant circuit 1, according to the modes envisaged. More specifically, the thermodynamic circuit 19 may operate equally in the following modes:

in a first mode, called air-conditioning mode, in which the first air flow 7 is cooled before it is distributed inside the motor vehicle interior;

in a second mode, which is referred to as energy source 39 air conditioning and cooling mode, wherein the first air flow 7 is cooled before it is distributed inside the motor vehicle interior, and wherein the energy source 39 is cooled by the circulation of a heat transfer liquid;

in a third mode, called motor vehicle air conditioning and window defogging mode, in which the first air flow 7 is dried and then heated before it is distributed within the motor vehicle interior;

in a fourth mode, called heat pump or heating mode, in which the first air flow 7 is heated before it is distributed inside the motor vehicle interior;

in a fifth mode, which is called energy source 39 heat pump and heating mode, wherein the first air flow 7 is heated before it is distributed inside the motor vehicle interior, and wherein the energy source 39 is heated by the circulation of a heat transfer liquid;

in a sixth mode, which is referred to as energy source 39 heat pump and cooling mode, wherein the first air flow 7 is heated before it is distributed inside the motor vehicle interior, and wherein the energy source 39 is cooled by the circulation of the heat transfer liquid;

in a seventh operating mode, which is referred to as an energy source cooling mode, wherein the energy source 39 is cooled;

in an eighth operating mode, which is referred to as an energy source heating mode, wherein the energy source 39 is heated.

By convention, in fig. 5 to 12, the flow-through

lines

28, 29, 30, 31, 32, 33, the

branches

13, 14, 15 and the

conduits

35, 37, 38 are shown as dashed lines when no fluid or liquid is circulated therethrough, while the flow-through

lines

28, 29, 30, 31, 32, 33, the

branches

13, 14, 15 and the

conduits

35, 37, 38 are shown as continuous lines when a heat transfer liquid is circulated therethrough.

Also, by convention, in fig. 5-12, the flow-through

lines

28, 29, 30, 31, 32, 33, the

legs

13, 14, 15 and the

tubes

35, 37, 38 are shown by arrows, the tips of which indicate the direction of flow of the refrigerant or heat transfer liquid within the flow-through

lines

28, 29, 30, 31, 32, 33, the

legs

13, 14, 15 and the

tubes

35, 37, 38.

In fig. 5, the thermodynamic circuit 19 is used in a first mode, referred to as the air conditioning mode, to cool the first air stream 7 before it is distributed inside. In this configuration, the first expansion member 12, the fourth control valve 104, the fifth control valve 105, and the third check valve 303 are closed, and the pump 34 is stopped.

Thereby, the refrigerant follows only the first flow line 28. In other words, the refrigerant is compressed in the compressor 20 so as to be changed to a high pressure HP, then circulates until the first junction point 201, then passes through the second control valve 102 (open position), then circulates until the second junction point 202, and then circulates in the third heat exchanger 21 where the refrigerant circulatesHeat is generated 21 to the second air stream 22. Then, the refrigerant circulates up to the third joint point 203, then passes through the first check valve 301 by bypassing the third expansion member 23, then circulates up to the fourth joint point 204, and then follows the first passage 25, in which first passage 25 the refrigerant generates heat to the refrigerant existing in the second passage 26. The refrigerant then circulates up to the fifth junction point 205, then through the second check valve 302 (open position), then up to the sixth junction point 206 and along the first branch 13, then circulates inside the first expansion device 2, wherein it undergoes a first expansion and transitions from a high pressure HP to a first low pressure LP lower than the high pressure HP₁。

The first expansion device 2 is configured to reduce the high pressure HP and generate a first low pressure LP₁. Then, the refrigerant circulates up to the branch point 16, wherein the refrigerant follows the second branch 14, so as to pass through the first control valve 101 (open position) and the second expansion member 5, undergo a second expansion therein, and from the first low pressure LP₁Transition to lower than first low pressure LP₁Second low pressure LP of₂. The expansion member 5 is configured to adjust the second low pressure LP₂. The refrigerant then circulates in the first heat exchanger 6 to cool the first air stream 7, then up to the connection point 17, then through the third control valve 103 (open position), then up to the seventh junction point 207, then through the accumulator 18, where the liquid refrigerant remains in a viable reserve, then flows in the second channel 26 of the fourth heat exchanger 24 for return to the compressor 20.

These arrangements are such that the refrigerant is at a high pressure HP between the compressor 20 and the first expansion device 2, and such that the refrigerant is at a first low pressure LP between the first expansion device 2 and the second expansion member 5₁And such that the refrigerant is at a second low pressure LP between the second expansion member 5 and the compressor 20₂. The result is that in this configuration the refrigerant undergoes two expansions in succession.

In fig. 6, the thermodynamic circuit 19 is used in a second mode, referred to as the air conditioning mode, to cool the first air stream 7 before it is distributed inside, and at the same time cool the heat source 39. In this configuration, the fourth control valve 104, the fifth control valve 105, and the third check valve 303 are closed. In this configuration, pump 34 is in the operating mode so as to circulate the heat transfer liquid within heat transfer liquid circuit 33, and three-way valve 36 allows the circulation of refrigerant within third conduit 38 and prevents the circulation of refrigerant within second conduit 37.

The refrigerant thus follows the first flow line 28 and advantageously the third branch 15, with respect to the previously described modes. In other words, the refrigerant is compressed in the compressor 20 at a high pressure HP, then circulates up to the first junction point 201, then passes through the second control valve 102 (open position), then circulates up to the second junction point 202, and then circulates in the third heat exchanger 21, where it generates heat to the second air stream 22. Then, the refrigerant circulates up to the third joint point 203, then passes through the first check valve 301 by bypassing the third expansion member 23, then circulates up to the fourth joint point 204, and then follows the first passage 25, in which first passage 25 the refrigerant captures heat from the refrigerant present in the second passage 26. The refrigerant then circulates up to the fifth junction point 205, then through the second check valve 302 (open position), then up to the sixth junction point 206 and follows the first branch 13, then circulates inside the first expansion device 2, wherein it undergoes a first expansion and transitions from a high pressure HP to a first low pressure LP lower than the high pressure HP₁. The refrigerant then circulates up to the branch point 16, where it follows the second branch 14 and the third branch 15.

A portion of the refrigerant along the second branch 14 passes through the first control valve 101 (open position) and the second expansion member 5, where it undergoes a second expansion and comes from the first low pressure LP₁Transition to lower than first low pressure LP₁Second low pressure LP of₂. The second expansion member 5 is configured to regulate the second low pressure LP₂. The refrigerant then circulates inside the first heat exchanger 6 in order to cool the first air flow 7, and then up to the connection point 17.

A portion of the refrigerant along the third branch 15 is inThe first passage 10 of the second heat exchanger 9 circulates so as to capture heat from the heat transfer liquid present in the second passage 11, then passes through the first expansion member 12 (open position) which maintains the second heat exchanger 9 at the second low pressure LP₂. The first expansion member 12 regulates the flow and pressure downstream of the first heat exchanger 6 and the second heat exchanger 9. The refrigerant then rejoins the connection point 17. The refrigerant then passes through the third control valve 103 (open position) and then circulates until the seventh junction point 207 and then through the accumulator 18, where a viable reserve of liquid refrigerant remains, and the refrigerant in the vapor phase circulates in the second passage 26 of the fourth heat exchanger 24 for return to the compressor 20.

These arrangements are such that the refrigerant is at a high pressure HP between the compressor 20 and the first expansion device 2, and such that the refrigerant is at a first low pressure LP between the first expansion device 2 and the second expansion member 5, and between the first expansion device 2 and the first expansion member 12₁And such that the refrigerant is at a second low pressure LP between the second expansion member 5 and the compressor 20, and between the first expansion member 12 and the compressor 20₂。

Furthermore, in the case where the pump 34 is operated and the three-way valve 36 is configured to allow the heat transfer fluid to circulate only within the first and

third conduits

35, 38, the heat transfer liquid picks up heat in the vicinity of the energy source 39 in order to generate it to the refrigerant in the vicinity of the second heat exchanger 9.

The result is that in this configuration the refrigerant undergoes two successive expansions in order to optimally cool the first air stream 7, and the refrigerant flow in the second heat exchanger 9 is regulated.

In fig. 7, the thermodynamic circuit 19 is used in a third mode, referred to as motor vehicle air conditioning and window defogging mode, in which the first airflow 7 is dried and then heated before it is distributed within the motor vehicle interior. In this configuration, the first expansion member 12, the fifth control valve 105, and the third check valve 303 are closed, and the pump 34 is stopped.

Thereby, the fluid follows the first and second flow-through

lines

28, 29. In other words, the refrigerant is compressed in the compressor 20 to become a high pressure HP, and then circulated up to the first junction point 201. A portion of the refrigerant follows the second flow line 29 and another portion of the refrigerant continues to circulate in the first flow line 28. This latter portion passes through the second control valve 102 (open position) and then circulates up to the second junction point 202 and then circulates in the third heat exchanger 21, where the refrigerant generates heat to the second air stream 22. Then, this portion of the refrigerant circulates up to the third joint point 203, then passes through the first check valve 301 by bypassing the third expansion member 23, then circulates up to the fourth joint point 204, and then follows the first passage 25, within which first passage 25, this portion of the refrigerant generates heat to the refrigerant present in the second passage 26. The refrigerant then circulates up to a fifth junction point 205, then through a second check valve 302 (open position), then up to a sixth junction point 206, where the portion of refrigerant rejoins another portion. This latter portion coming from the first junction 201 circulates inside the fifth heat exchanger 27 in order to heat the first air flow 7 (said first air flow 7 is cooled and advantageously dried during its previous passage through the first heat exchanger 6) and then passes through the fourth control valve 104 (open position) before rejoining the sixth junction 206.

The refrigerant also circulates in the first branch 13 and then in the first expansion device 2, where it undergoes a first expansion and passes from the high pressure HP to a first low pressure LP lower than the high pressure HP₁. Then, the refrigerant circulates up to the branch point 16, wherein the refrigerant follows the second branch 14, so as to pass through the first control valve 101 (open position) and the second expansion member 5, undergo a second expansion therein, and from the first low pressure LP₁Transition to lower than first low pressure LP₁Second low pressure LP of₂Then circulates in the first heat exchanger 6 in order to cool and dry the first air flow 7, then circulates up to the connection point 17, then passes through the third control valve 103 (open position), then circulates up to the seventh junction point 207, then passes through the accumulator 18, in which the liquid refrigerant remains in a viable reserve, then in the second heat exchanger 24 of the fourth heat exchanger 24Flow within the passage 26 is for return to the compressor 20.

These arrangements are such that the refrigerant is at a high pressure HP between the compressor 20 and the first expansion device 2, and between the compressor 20 and the sixth junction 206, and such that the refrigerant is at a first low pressure LP between the first expansion device 2 and the second expansion member 5₁And such that the refrigerant is at a second low pressure LP between the second expansion member 5 and the compressor 20₂。

The end result is that in this configuration the refrigerant undergoes two expansions in succession in order to cool and dry the first air stream 7, wherein the first heat exchanger 6 acts as an evaporator with walls on which the moisture carried by the first air stream 7 condenses, the first dried air stream 7 then being heated as it passes through the fifth heat exchanger 27, which acts as a cooler for the refrigerant.

In fig. 8, the thermodynamic circuit 19 is used in a fourth mode, called heat pump mode, in which the first air flow 7 is heated before it is distributed inside the motor vehicle. In this configuration, the first expansion member 12, the second control valve 102, the third control valve 103, and the first check valve 301 are closed, and the pump 34 is stopped.

The refrigerant thus follows the second flow line 29, the third flow line 30, the fourth flow line 31, the fifth flow line 32, and partly the first flow line 28. In other words, the refrigerant is compressed in the compressor 20 to become a high pressure HP, and then circulated up to the first junction point 201. The refrigerant then follows the second flow line 29 and passes through the fifth heat exchanger 27, in which it generates heat to the first air flow 7, in order to heat said flow before it is distributed in the interior of the motor vehicle.

The refrigerant then passes through the fourth control valve 104 (open position) to reach the sixth junction point 206. Then, the refrigerant follows the first branch 13 and then circulates in the first expansion device 2, and the first expansion device 2 is fully opened so that no expansion occurs therein. The refrigerant then flows through to the branch point 16, where it is cooledThe agent follows the second branch 14 so that, through the first control valve 101 (open position) and the second expansion member 5, the refrigerant undergoes a first expansion therein and passes from the high pressure HP to a first low pressure LP lower than the high pressure HP₁And then circulates inside the first heat exchanger 6 in order to cool and dry the first air flow 7, and then circulates up to the connection point 17. The refrigerant then follows the fourth flow line 31 and passes through the third check valve 303 (open position) to reach the fifth junction point 205. The refrigerant then follows the first pass 25 of the fourth heat exchanger 24, where it generates heat to the refrigerant present in the second pass 26. The refrigerant then reaches the fourth junction point 204 and then passes through the third expansion member 23, where it undergoes a second expansion and from the first low pressure LP₁Transition to lower than first low pressure LP₁Second low pressure LP of₂And then circulates in the third heat exchanger 21, where the refrigerant captures heat from the second air stream 22, in other words, it heats up in contact with the second air stream 22. The refrigerant then reaches the second junction 202 so as to follow the third flow line 30 and passes through the fifth control valve 105 (open position) and rejoins the seventh junction 207 so as to follow the first flow line 28. The refrigerant then passes through the accumulator 18, where a viable reserve of liquid refrigerant is maintained, and then circulates in the second pass 26 of the fourth heat exchanger 24 for return to the compressor 20.

These arrangements are such that the refrigerant is at a high pressure HP between the compressor 20 and the second expansion member 5, and such that the refrigerant is at a first low pressure LP between the second expansion member 5 and the third expansion member 23₁And such that the refrigerant is at a second low pressure LP between the third expansion member 23 and the compressor 20₂。

The end result is that, in this configuration, the refrigerant output from the compressor 2 heats the first air stream 7 within the fifth heat exchanger 27 and then undergoes two expansions, including the first expansion within the second expansion member 5, in succession, to ensure that the pressure remains below a certain critical value within the first heat exchanger 6, which acts as an evaporator with walls on which the moisture carried by the first air stream 7 condenses, the first dried air stream 7 then being heated as it passes through the fifth heat exchanger 27.

In fig. 9, the thermodynamic circuit 19 is used in a fifth mode, referred to as the energy source 39 heat pump and heating mode, wherein the first air stream 7 is heated before it is distributed within the motor vehicle interior, and wherein the energy source 39 is heated by circulation of a heat transfer liquid. In this configuration, the first expansion member 12 is opened to provide the refrigerant flow in the second heat exchanger 9, while the second control valve 102, the third control valve 103, and the first check valve 301 are closed. The pump 34 is operating and the three-way valve 36 allows the heat transfer liquid to circulate between the first conduit 35 and the third conduit 38 and prevents such circulation within the second conduit 37.

The refrigerant thus follows the second flow line 29, the third flow line 30, the fourth flow line 31, the fifth flow line 32, and advantageously the third branch 15, and partly the first flow line 28. In other words, the refrigerant is compressed in the compressor 20 to become a high pressure HP, and then circulated up to the first junction point 201. The refrigerant then follows the second flow line 29 and passes through the fifth heat exchanger 27, in which it generates heat to the first air flow 7 in order to heat said flow before it is distributed in the interior of the motor vehicle. The refrigerant then passes through the fourth control valve 104 (open position) to reach the sixth junction point 206. The refrigerant then follows the first branch 13 and then circulates inside the first expansion device 2, which is fully open so that no expansion takes place therein. The refrigerant then circulates up to the branch point 16, where a part of the refrigerant follows the second branch 14 and another part of the refrigerant follows the third branch 15.

A portion of the refrigerant following the second branch 14 passes through the first control valve 101 (open position) and the second expansion member 5, in which it undergoes a first expansion and transitions from a high pressure HP to a first low pressure LP lower than the high pressure HP₁And then circulates inside the first heat exchanger 6 in order to cool and dry the first air flow 7, and then circulates up to the connection point 17.

A portion of the refrigerant following the third branch 15 circulates inside the first passage 10 of the second heat exchanger 9, so as to generate heat to the heat transfer liquid present inside the second passage 11, and then passes through the first expansion member 12 (open position). The first expansion member 12 regulates the flow and pressure downstream of the first heat exchanger 6 and the second heat exchanger 9. This portion of the refrigerant then rejoins the connection point 17. The refrigerant then follows the fourth flow line 31 and passes through the third check valve 303 (open position) to reach the fifth junction point 205. The refrigerant then follows the first pass 25 of the fourth heat exchanger 24, where it generates heat to the refrigerant present in the second pass 26. The refrigerant then reaches the fourth junction point 204 and then passes through the third expansion member 23, where it undergoes a second expansion and from the first low pressure LP₁Transition to lower than first low pressure LP₁Second low pressure LP of₂And then circulates within third heat exchanger 21 where the refrigerant extracts heat from second air stream 22. The refrigerant then reaches the second junction 202 so as to follow the third flow line 30 and passes through the fifth control valve 105 (open position) and rejoins the seventh junction 207 so as to follow the first flow line 28. The refrigerant then passes through the accumulator 18, where a viable reserve of liquid refrigerant is maintained, and then circulates in the second pass 26 of the fourth heat exchanger 24 for return to the compressor 20.

These arrangements are such that the refrigerant is at a high pressure HP between the compressor 20 and the second expansion member 5, and between the compressor 2 and the first expansion member 12, and such that the refrigerant is at a first low pressure LP between the second expansion member 5 and the third expansion member 23, and between the first expansion device 12 and the first expansion member 23₁And such that the refrigerant is at a second low pressure LP between the third expansion member 23 and the compressor 20₂。

The end result is that, in this configuration, the refrigerant output from the compressor 2 heats the first air stream 7 inside the fifth heat exchanger 27 and at the same time heats the heat transfer liquid, so as to eventually heat the energy source 39 and either undergo expansion in the second expansion means 5 or adjust the flow rate through the first expansion means 12, in particular to ensure that the pressure remains below a certain threshold in the first heat exchanger 6, which acts as an evaporator with walls on which the moisture carried by the first air stream 7 condenses, the first dried air stream 7 then being heated as it passes through the fifth heat exchanger 27.

In fig. 10, the thermodynamic circuit 19 is used in a sixth mode, referred to as energy source 39 heat pump and cooling mode, in which the first air flow 7 is heated before it is distributed within the motor vehicle interior, and in which the energy source 39 is cooled by the circulation of the heat transfer liquid. In this configuration, the first expansion member 12 is fully open, while the first control valve 101, the second control valve 102, the fifth control valve 105, the first check valve 301 and the second check valve 302 are closed, and the pump 34 is operated, the three-way valve 36 allowing the passage of the heat transfer liquid between the first conduit 35 and the third conduit 38 and preventing such passage within the second conduit 37.

The refrigerant thus follows the portions of the second flow line 29, the fourth flow line 30, and advantageously the third branch 15, as well as the first flow line 28. In other words, the refrigerant is compressed in the compressor 20 to become a high pressure HP, and then circulated up to the first junction point 201. The refrigerant then follows the second flow line 29 and passes through the fifth heat exchanger 27, in which it generates heat to the first air flow 7 in order to heat said flow before it is distributed in the interior of the motor vehicle. The refrigerant then passes through the fourth control valve 104 (open position) to reach the sixth junction point 206. The refrigerant then follows the first branch 13 and then circulates inside the first expansion device 2, where it undergoes, according to the operating mode, the only expansion that it undergoes in the thermodynamic circuit 19.

Thereby, the refrigerant transitions from a high pressure HP to a low pressure LP within the first expansion device 2. The refrigerant then circulates up to the branch point 16, where it follows the third branch 15. The refrigerant circulates in the first passage 10 of the second heat exchanger 9 so as to capture the heat in the heat transfer liquid present in the second passage 11, and then passes through the first expansion member 12, which is in the fully open position. The refrigerant then rejoins the connection point 17. The refrigerant then follows the first flow line 28, passes through the third control valve 103 (open position), then through the accumulator 18, where the liquid refrigerant remains in a viable reserve, and then circulates in the second passage 26 of the fourth heat exchanger 24 for return to the compressor 20.

These arrangements are such that the refrigerant is at a high pressure HP between the compressor 20 and the first expansion device 2, and such that the refrigerant is at a low pressure LP between the first expansion device 2 and the compressor 20.

The end result is that, in this configuration, the refrigerant output from the compressor 2 heats the first air stream 7 passing through the fifth heat exchanger 27 and cools the heat transfer liquid to ultimately cool the energy source 39.

In FIG. 11, the thermodynamic circuit 19 is used in a seventh mode, referred to as the energy source 39 cooling mode. In this configuration, the first control valve 101, the fourth control valve 104, the fifth control valve 105, and the third check valve 303 are closed. In this configuration, pump 34 is in the operating mode so as to circulate the heat transfer liquid within heat transfer liquid circuit 33, and three-way valve 36 allows the circulation of the heat transfer liquid within third conduit 38 and prevents the circulation of refrigerant within second conduit 37.

The refrigerant thus partially follows the first flow line 28 and, advantageously, the third branch 15. In other words, the refrigerant is compressed in the compressor 20 at a high pressure HP, then circulates up to the first junction point 201, then passes through the second control valve 102 (open position), then circulates up to the second junction point 202, and then circulates in the third heat exchanger 21, where it generates heat to the second air stream 22. The refrigerant then circulates up to the third junction point 203, then passes through the first check valve 301 due to bypassing the third expansion member 23, then circulates up to the fourth junction point 204, and then follows the first passage 25, in which first passage 25 the refrigerant generates heat to the refrigerant present in the second passage 26. The refrigerant then circulates up to the fifth junction point 205, then through the second check valve 302 (open position), then up to the sixth junction point 206 and follows the first branch 13, then inside the first expansion device 2, where it undergoes the only expansion that it undergoes inside the thermodynamic circuit 19, according to this mode of operation. Thereby, the refrigerant transitions from a high pressure HP to a low pressure LP below the high pressure HP. The refrigerant then circulates up to the branch point 16, where it follows the third branch 15. The refrigerant circulates in the first channel 10 of the second heat exchanger 9 so as to capture the heat in the heat transfer liquid present in the second channel 11, then passes through the first expansion member 12, which is arranged in the fully open position and in which the refrigerant does not undergo any pressure drop. The refrigerant then rejoins the connection point 17. The refrigerant then passes through the third control valve 103 (open position) and then circulates until the seventh junction point 207 and then through the accumulator 18, where the liquid refrigerant remains in a viable reserve, and then circulates in the second passage 26 of the fourth heat exchanger 24 for return to the compressor 20.

third conduits

35, 38, the heat transfer fluid picks up heat in the vicinity of the energy source 39 in order to generate it to the refrigerant in the vicinity of the second heat exchanger 9.

As a result, in this configuration, the refrigerant undergoes a single expansion to optimally cool the energy source 39.

In fig. 12, the thermodynamic circuit 19 is used in an eighth mode, referred to as the energy source 39 heating mode, in which the energy source 39 is heated by the circulation of the heat transfer liquid. In this configuration, the first expansion member 12 is fully opened so that the refrigerant does not undergo any pressure drop or flow rate reduction, while the first control valve 101, the second control valve 102, the electric control valve 103, and the first check valve 301 and the second check valve 302 are closed. The pump 34 is operating and the three-way valve 36 allows the heat transfer liquid to circulate between the first conduit 35 and the third conduit 38 and prevents such circulation within the second conduit 37.

The refrigerant thus follows the second flow line 29, the third flow line 30, the fourth flow line 31, the fifth flow line 32, and advantageously the third branch 15, and partly the first flow line 28. In other words, the refrigerant is compressed in the compressor 20 to become a high pressure HP, and then circulated up to the first junction point 201. The refrigerant then follows the second flow line 29 and passes through the fifth heat exchanger 27, in which it generates heat to the first air flow 7 in order to heat said flow before it is distributed in the interior of the motor vehicle.

According to a variant, no first air stream 7 circulates inside the shell of the heating, ventilation and/or air-conditioning installation 8, so that the refrigerant does not generate any heat inside the fifth heat exchanger 27. The refrigerant then passes through the fourth control valve 104 (open position) to reach the sixth junction point 206. The refrigerant then follows the first branch 13 and then circulates inside the first expansion device 2, which is fully open so that no expansion takes place therein. The refrigerant then circulates up to the branch point 16, where it follows the third branch 15. The refrigerant circulates in the first channel 10 of the second heat exchanger 9 so as to generate heat to the heat transfer liquid present in the second channel 11, and then passes through the first expansion member 12, which is arranged in the fully open position and in which no pressure drop occurs. The refrigerant then rejoins the connection point 17. The refrigerant then follows the fourth flow line 31 and passes through the third check valve 303 (open position) to reach the fifth junction point 205. The refrigerant then follows the first pass 25 of the fourth heat exchanger 24, where it generates heat to the refrigerant present in the second pass 26. The refrigerant then reaches the fourth junction point 204 and then passes through the third expansion member 23 where, depending on the mode of operation, the refrigerant undergoes the only expansion that the refrigerant undergoes in the thermodynamic circuit 19. The refrigerant thus transitions from a high pressure HP to a low pressure LP lower than the high pressure HP and then circulates within the third heat exchanger 21, where it captures heat from the second air stream 22. The refrigerant then reaches the second junction 202 so as to follow the third flow line 30 and passes through the fifth control valve 105 (open position) and rejoins the seventh junction 207 so as to follow the first flow line 28. The refrigerant then passes through the accumulator 18, where a viable reserve of liquid refrigerant is maintained, and then circulates in the second pass 26 of the fourth heat exchanger 24 for return to the compressor 20.

These arrangements are such that the refrigerant is at a high pressure HP between the compressor 20 and the third expansion member 23, and such that the refrigerant is at a low pressure LP between the third expansion member 23 and the compressor 20.

The end result is that, in this configuration, the refrigerant output from the compressor 2 quickly and efficiently heats the heat transfer liquid to ultimately heat the energy source 39 and undergoes only one expansion within the third expansion member 23.

From all of these arrangements, the thermodynamic circuit 19 of the present invention connected to the heat transfer liquid circuit 33 can be thermally controlled in an efficient manner. More particularly, such an arrangement of the thermodynamic circuit 19 allows control of the first heat exchanger 6, the first expansion device 2 and the first expansion means 12, based on a coordinated control of the first heat exchanger 6 and the second heat exchanger 9, in particular when said two exchangers are implemented.

Such an arrangement of the thermodynamic circuit 19 allows a smooth, unobstructed transition of the mass flow between the second branch 14 and the third branch 15, the third heat exchanger 21 acting equally as an evaporator or condenser. Even more particularly, the first thermal expansion means 2 can be optimized for the high pressure HP of the supercritical or subcritical refrigerant by controlling the mass flow, the expansion being a result of the control of the mass flow. The division into two branches at the branching point 16 for the second branch 14 allows the pressure at the first heat exchanger 6 to be reduced by the second expansion means 3 upstream of the first heat exchanger 6, the pressure of the refrigerant prevailing in the first heat exchanger 6 being lower than the pressure of the refrigerant prevailing in the second heat exchanger 9. With the third branch passage 15, the division into two at the branch point 16 allows the refrigerant flow rate to be controlled through the first expansion member 12.

From all these arrangements, optimizing the high pressure HP also allows the coefficient of performance (COP) of the thermodynamic circuit 19 to be optimized. Thus, when an optimized high pressure is reached, the consumption of the compressor 2 is minimal for a given temperature set point set within the interior of the motor vehicle.

The temperature of the first air stream 7 is controlled by the mass flow of refrigerant, which remains dependent on the rotational speed of the compressor 2. The second expansion member 5 is arranged such that the evaporation temperature is generated at a lower pressure than that for cooling the heat transfer liquid. . In either of the above "heat pump" modes, the exchanger may also prevent excessive pressure from being experienced within the first heat exchanger 6 when the second expansion member 5 is used as a gas condenser or cooler.

From all these arrangements, it follows that the first expansion member 12 is not only able to maintain an intermediate pressure within the second heat exchanger 9, in particular due to the control of the mass flow, which itself controls the superheating at the output of the second heat exchanger 9 in order to reach the required temperature of the energy source 39, but is also able to coordinate the refrigerant pressures at the outputs of the first and

second heat exchangers

6, 9.

It is also necessary to limit the refrigerant pressure at the output of the second heat exchanger 9, since even in the presence of the first expansion member 12, in any "air-conditioning" operating mode of the first air flow 7, the pressure of the refrigerant at the output of the second heat exchanger 9 must not exceed the optimal high pressure required for the temperature of the first heat exchanger 6.

From all these arrangements, it is also possible for the thermodynamic circuit 19 to provide the functions of the various modes, based on the following behaviour of the first heat exchanger 6 and the second heat exchanger 9 (as described in the following tables):

fig. 13 shows a mollier diagram of the thermal performance of the refrigerant circuit 1 as shown in fig. 2 and operating according to the second mode shown in fig. 6, referred to as energy source 39 air conditioning and cooling mode, in which the first air stream 7 is cooled before it is distributed within the interior of the motor vehicle, and in which the energy source 39 is cooled by the circulation of a heat transfer liquid. For the purposes of example, the refrigerant is supercritical, particularly carbon dioxide.

The section AB represents the second low pressure LP of the refrigerant achieved by the compressor 20₂Until compression of the high pressure HP, during which the pressure and enthalpy of the refrigerant increase. Segment BC represents the constant pressure cooling of the successive refrigerant in the third heat exchanger 21 and then in the fourth heat exchanger 24. Section CD represents the first isenthalpic expansion effected in the first expansion device 2, in which the refrigerant transitions from a high pressure HP to a first low pressure LP₁. The section DE indicates a second isenthalpic expansion carried out in the second expansion device 5, in which the refrigerant is brought from the first low pressure LP₁Transition to second Low pressure LP₂. Section EF represents the isobaric cooling of the refrigerant in the first heat exchanger 6. Section DH represents isobaric cooling of the refrigerant in the second heat exchanger 9. The segment HF represents the isenthalpic expansion accomplished within the first expansion member 12. The section FA particularly represents the heating of the refrigerant in the third heat exchanger 21.

Claims

1. A refrigerant circuit (1) in which a refrigerant can flow, the refrigerant circuit (1) comprising at least one first heat exchanger (6) and at least one second heat exchanger (9), characterized in that said refrigerant circuit (1) comprises a first branch (13) provided with a first expansion device (2), the first branch (13) comprising a branch point (16) common to the second branch (14) and the third branch (15), the second branch (14) is provided with a second expansion device (3) and a first heat exchanger (6), the second expansion means (3) being interposed between the branch point (16) and the first heat exchanger (6), the third branch (15) being provided with a second heat exchanger (9) and a first expansion member (12), the second heat exchanger (9) being interposed between the branch point (16) and the first expansion means (12);

wherein the refrigerant transitions from a high pressure to a first low pressure within the first expansion device (2); the first low pressure is lower than the high pressure;

wherein refrigerant transitions from the first low pressure to a second low pressure within the second expansion device (3); the second low pressure is lower than the first low pressure; the second expansion device (3) is arranged upstream of the first heat exchanger (6).

2. Refrigerant circuit (1) as claimed in claim 1, wherein the second expansion means (3) comprise a second expansion member (5) having a constant cross section.

3. Refrigerant circuit (2) as claimed in claim 2, wherein the second expansion means (3) comprise a first valve (101) for controlling the refrigerant flow in the second branch (14), said first valve being interposed between the branch point (16) and the second expansion member (5).

4. Refrigerant circuit (1) according to any of the preceding claims, wherein the first expansion member (12) is a valve for regulating the refrigerant flow.

5. Refrigerant circuit (1) according to claim 1, wherein the refrigerant circuit (1) is provided with an accumulator (18), said accumulator (18) being interposed, in the direction of circulation of the refrigerant within the refrigerant circuit (1), between the first heat exchanger (6) and the connection point (17) common to the second branch (14) and the third branch (15), or being arranged downstream of the connection point (17) common to the second branch (14) and the third branch (15).

6. Refrigerant circuit (1) according to claim 1, wherein the first heat exchanger (6) is arranged to thermally treat the first air flow and the second heat exchanger (9) is arranged to exchange heat with a heat transfer liquid circulating within a heat transfer liquid circuit (33) comprising an energy source (39).

7. Refrigerant circuit (1) according to claim 1, wherein the third branch (15) is provided with the first passage (10) of the second heat exchanger (9).

8. A thermodynamic circuit (19) comprising a refrigerant circuit (1) according to any one of the preceding claims, wherein the first flow-through line (28) comprises successively a compressor (20), a first junction point (201), a second control valve (102), a second junction point (202), a third heat exchanger (21), a third junction point (203), a first check valve (301), a fourth junction point (204), a first passage (25) of the fourth heat exchanger (24), a fifth junction point (205), a second check valve (302), a sixth junction point (206), a first branch (13), a branch point (16), a second branch (14), a connection point (17) common to the second branch (14) and the third branch (15), a third control valve (103), a seventh junction point (207) and a second passage (26) for returning to the fourth heat exchanger (24) of the compressor (20).

9. The thermodynamic circuit (19) according to claim 8, comprising a second refrigerant flow line (29) extending between the first junction point (201) and the sixth junction point (206), the second refrigerant flow line (29) comprising successively the fifth heat exchanger (27) and the fourth control valve (104) from the first junction point (201) towards the sixth junction point (206).

10. The thermodynamic circuit (19) according to any one of claims 8 to 9, comprising a third refrigerant flow line (30), the third refrigerant flow line (30) extending between the second junction point (202) and the seventh junction point (207) and comprising a fifth control valve (105).

11. The thermodynamic circuit (19) according to claim 8, comprising a fourth flow line (31), said fourth flow line (31) extending between the connection point (17) and the fifth junction point (205) and comprising a third check valve (303).

12. The thermodynamic circuit (19) according to claim 8, comprising a fifth flow line (32), the fifth flow line (32) extending between a third junction point (203) and a fourth junction point (204) and comprising a third expansion member (23).

13. An assembly (19, 33) formed by a thermodynamic circuit (19) according to any one of claims 8 to 12 and a heat transfer liquid circuit (33), wherein the heat transfer liquid circuit (33) comprises a first conduit (35) with a pump (34), a second passage (11) of the second heat exchanger (9) and a three-way valve (36) distributing the heat transfer liquid towards the second conduit (37) or towards a third conduit (38), the second conduit (37) being a conduit for bypassing the third conduit (38), the third conduit (38) being arranged to exchange heat with an energy source (39).

14. A method for implementing an assembly (19, 33) according to claim 13, wherein the compressor (20) is operated so as to deliver refrigerant at High Pressure (HP).

15. A method according to claim 14, the method being implemented in a first mode, wherein the first expansion device (2) allows expansion, the first expansion member (12) is closed, the first control valve (101) is open, the second control valve (102) is open, the third control valve (103) is open, the fourth control valve (104) is closed, the fifth control valve (105) is closed, the first check valve (301) is open, the second check valve (302) is open, the third check valve (303) is closed, and the pump (34) is stopped.