DE102020130196A1 - Refrigeration system for a motor vehicle with an additional heat exchanger as an undercooling section, motor vehicle with such a refrigeration system - Google Patents

Abstract

A refrigeration system (10) for a motor vehicle is described, the refrigeration system (10) comprising: a refrigerant compressor (12); a first, indirectly acting heat exchanger (18) which is arranged downstream of the refrigerant compressor (12) in relation to a flow direction of refrigerant and in which the condensation of refrigerant takes place; and at least one evaporator (22) with a valve device (AE2) assigned to the evaporator (22), in particular an assigned expansion valve. It is provided that at least one second, directly or indirectly acting heat exchanger (40) is arranged downstream of the first heat exchanger (18) with respect to the direction of flow of refrigerant in cooling mode of the refrigeration system (10), in which further cooling or supercooling of the refrigerant takes place.

Description

The invention relates to a refrigeration system for a motor vehicle, the refrigeration system comprising: a refrigerant compressor; a first, indirectly acting heat exchanger, which is arranged downstream of the refrigerant compressor in relation to a flow direction of refrigerant and in which cooling and/or condensation of refrigerant takes place; and at least one evaporator with a valve device assigned to the evaporator, in particular an assigned expansion valve.

From the DE 10 2012 212 227 A1 a refrigeration system of a motor vehicle is known with a heat transfer device which has a sub-cooling section arranged in front of an expansion device.

From the DE 10 2017 212 309 B3 a coolant circuit of a motor vehicle with at least two coolant circuits and a latent heat accumulator is known, the coolant circuit having a supercooling section. No refrigeration system or refrigerant circuit is described.

It has been shown that in refrigeration systems for electrically powered motor vehicles with an indirectly acting first heat exchanger, which can also be referred to as an external heat exchanger, a higher refrigerant mass flow and thus a higher flow rate at the refrigerant compressor is required for performance-optimized operation. Furthermore, an increased delivery volume at the refrigerant compressor can sometimes be heard acoustically in an interior of the vehicle (high compressor output), which is undesirable. Furthermore, such (indirect) systems usually work at higher pressure ratios, which in turn have an adverse effect on system efficiency.

The object on which the invention is based is seen as specifying a refrigeration system in which the efficiency of operation can be improved while maintaining the required system performance.

This object is achieved by a refrigeration system with the features of patent claim 1 and by a motor vehicle with such a refrigeration system. Advantageous configurations with expedient developments are specified in the dependent patent claims.

A refrigeration system for a motor vehicle is therefore proposed, the refrigeration system comprising: a refrigerant compressor; a first, indirectly acting heat exchanger, which is arranged downstream of the refrigerant compressor in relation to a flow direction of refrigerant and in which cooling and/or condensation of refrigerant takes place; and at least one evaporator with a valve device assigned to the evaporator, in particular an assigned expansion valve. It is provided that at least one second, directly or indirectly acting heat exchanger is arranged downstream of the first heat exchanger with respect to the direction of flow of refrigerant in cooling mode (AC mode) of the refrigeration system, in which further cooling/cooling or supercooling of the refrigerant takes place.

With regard to the mode of operation of the heat exchanger described here, it is pointed out that air, in particular ambient air, acts directly on a directly acting heat exchanger, ie direct heat transfer takes place between air and refrigerant. An indirectly acting heat exchanger has a coolant circuit, with the heat being transferred between coolant and refrigerant. The coolant can be cooled, for example, in a cooler contained in the coolant circuit and acted upon by (ambient) air.

The efficiency of the refrigeration system can be improved by integrating at least one second, directly or indirectly acting heat exchanger. The temperature level of the refrigerant can be lowered further as a result of the further cooling down/cooling down or supercooling, so that more heat can be absorbed elsewhere in the refrigerant circuit, for example in the evaporator. In other words, the second heat exchanger, which causes supercooling of the refrigerant, achieves an enthalpy gain, as a result of which a reduced refrigerant mass flow is required to achieve the same refrigeration capacity. Due to the design of the extended or additional cooling/cooling section or sub-cooling section as a directly or indirectly acting heat exchanger, the air acting on the heat exchanger or the coolant circulating in the heat exchanger can act as heat sinks that can effectively extract heat from the coolant.

In the refrigeration system, the first indirectly acting heat exchanger can be connected to a first coolant circuit in which a first coolant circulates, and the second heat exchanger can be connected as an indirect heat exchanger to a second coolant circuit in which a second coolant circulates. The composition of the second coolant can correspond to that of the first coolant. In relation to the circuit, the second coolant can circulate independently of the first coolant. With other words The first and second coolants circulate in separate coolant circuits.

The refrigeration system can have at least one third heat exchanger, in particular a chiller, which in terms of flow is arranged parallel to or in series with the evaporator. In particular, the parallel arrangement in terms of flow technology offers flexible operating settings for the operation of the refrigeration system, because refrigerant can be routed through the evaporator and/or the third heat exchanger (chiller) as desired. The third heat exchanger can in particular be set up to dissipate waste heat from at least one electrical component of the motor vehicle, such as a high-voltage battery, by means of a coolant circuit, with the heated coolant being able to give off the heat in the third heat exchanger or chiller to the refrigerant to be evaporated.

In the refrigeration system, the second coolant circuit can be connected to the third heat exchanger, in particular a chiller. The second coolant circuit can be designed with the second heat exchanger and the third heat exchanger, in particular a chiller, in such a way that the second heat exchanger is charged with coolant that essentially has the lowest temperature in the second coolant circuit. In other words, the second heat exchanger, which is used for the supercooling of refrigerant, is the next component downstream of the third heat exchanger or chiller in the flow direction of the coolant. One can also say that the second heat exchanger is directly downstream of the third heat exchanger or chiller. In this way, it can be ensured that coolant with the lowest possible temperature is always present in the second heat exchanger, so that heat can be withdrawn from the coolant and this can be cooled off or supercooled.

The refrigeration system can have a bypass section in the refrigerant circuit, which is set up to bypass the second heat exchanger. As a result, a second heat exchanger to be used for cooling down/cooling down or subcooling of refrigerants can also be used in a refrigeration system with a heat pump function, with no subcooling taking place or being necessary in heat pump operation.

The bypass section can branch off between the first heat exchanger and the second heat exchanger and be connected to the refrigerant circuit downstream of the second heat exchanger in relation to the flow direction of refrigerant in cooling operation of the refrigeration system.

In addition, a shut-off device, in particular designed as a check valve, can be arranged downstream of the second heat exchanger and upstream of the connection of the bypass section to the refrigerant circuit. This can prevent refrigerant from flowing back if the refrigerant is to bypass the second heat exchanger.

A valve device, in particular a shut-off valve, can be arranged between the branch of the bypass section and the second heat exchanger, which is set up to release or prevent the flow of refrigerant through the second heat exchanger. Furthermore, the bypass section can have a bypass valve device, in particular a shut-off valve, which is set up to release or prevent the flow of refrigerant through the bypass section. By means of at least one of the aforementioned valve devices, it is possible to integrate the bypass section or the second heat exchanger into the refrigerant circuit or to exclude it from the flow of refrigerant. This supports the use or installation of a second heat exchanger for the subcooling of refrigerants in a refrigeration system with a heat pump function.

In a further embodiment of the bypass valve device as an infinitely variable valve, any intermediate position can be made possible in addition to the functional depiction of complete blocking or flow, which in turn can be used for extended heat management within the process control. Simultaneous flow through both refrigerant lines is made possible with different refrigerant distributions.

The second heat exchanger can be provided on the air side with a (continuously) closable cooling air inlet, which in turn can have a positive effect on said refrigerant distribution, especially at lower ambient temperatures.

A motor vehicle, in particular an at least partially electrically driven motor vehicle, can be equipped with a refrigeration system as described above. In an electric vehicle, the efficient operation of the refrigeration system with the integration of a second heat exchanger as a cooling/cooling section or supercooling section can lead to electricity savings, so that a greater range of the electric vehicle can be achieved.

In the motor vehicle, the second heat exchanger can be connected upstream of a cooler package of the motor vehicle as a directly acting heat exchanger based on an air flow. Alternatively can the second heat exchanger can be arranged as a directly acting heat exchanger in the area of an apron of the motor vehicle, in particular in a separately designed air duct. Furthermore, the second heat exchanger can be arranged or attached to the side and/or below a cooler or cooler package, which is usually arranged in the middle.

• 1 ein schematisches und vereinfachtes Schaltbild einer Kälteanlage für ein Kraftfahrzeug;
• 2 ein schematisches und vereinfachtes Schaltbild einer weiteren Kälteanlage für ein Kraftfahrzeug;
• 3 ein schematisches und vereinfachtes Schaltbild einer weiteren Kälteanlage für ein Kraftfahrzeug;
• 4 ein schematisches und vereinfachtes Schaltbild einer weiteren Kälteanlage für ein Kraftfahrzeug;
• 5 ein schematisches und vereinfachtes Schaltbild einer weiteren Kälteanlage für ein Kraftfahrzeug;
• 6 eine schematische und vereinfachte Darstellung eines Kraftfahrzeugs.

Further advantages and details of the invention result from the following description of embodiments with reference to the figures. It shows:

• 1 a schematic and simplified circuit diagram of a refrigeration system for a motor vehicle;
• 2 a schematic and simplified circuit diagram of another refrigeration system for a motor vehicle;
• 3 a schematic and simplified circuit diagram of another refrigeration system for a motor vehicle;
• 4 a schematic and simplified circuit diagram of another refrigeration system for a motor vehicle;
• 5 a schematic and simplified circuit diagram of another refrigeration system for a motor vehicle;
• 6 a schematic and simplified representation of a motor vehicle.

In 1 an embodiment of a refrigeration system 10 for a motor vehicle is shown schematically and in simplified form. The refrigeration system 10 includes a refrigerant circuit 11, which can be operated in a refrigeration system mode (also called AC mode for short). The refrigeration system 10 includes a refrigerant compressor 12, an indirectly acting first (external) heat exchanger 18 and a first evaporator 22. The first evaporator 22 is preceded by a first expansion element, in particular an expansion valve AE2.

The first heat exchanger 18 is connected to a coolant circuit 18.1 indicated here. In the first heat exchanger, heat is thus released from the heated and high-pressure refrigerant to the coolant in the coolant circuit 18.1. The coolant in the coolant circuit 18.1 can in turn be cooled by means of a cooler which is acted upon by air, for example, and which is not shown here.

The first heat exchanger 18 can be designed with a high-pressure-side refrigerant reservoir 19, also referred to as a collector, illustrated here as a rectangle. The collector 19 is provided on the outlet side on the first heat exchanger 18 in the refrigerant circuit 11 . Alternatively, a low-pressure-side refrigerant collector 24 (low-pressure accumulator) can be provided, which is shown in broken lines.

A second heat exchanger 40 is arranged downstream of the first heat exchanger 18, which acts or is used as a gas cooler or condenser (liquefier). The second heat exchanger 40 serves or is set up to bring about additional cooling/cooling or supercooling of the refrigerant. In the example of 1 the second heat exchanger 40 is designed as a directly acting heat exchanger, ie air, in particular ambient air UL, is applied directly to it in order to extract heat from the refrigerant. In other words, the second heat exchanger 40 forms an after-cooling or sub-cooling section in the refrigerant circuit 11.

2 shows a to 1 essentially the same structure refrigeration system 10, so that for components already described reference to the description of 1 can be taken. In contrast to the directly acting second heat exchanger 40 of 1 is the second heat exchanger 40a of 2 designed as an indirect heat exchanger. The second heat exchanger 40a is connected here to a coolant circuit 40.1. The coolant circuit 40.1 can also be referred to as the second coolant circuit 40.1 in relation to the entire refrigeration system 10, with the coolant circuit 18.1 assigned to the first heat exchanger 18 being able to be referred to as the first coolant circuit. The coolant circuit 40a of the second heat exchanger 40a can have, for example, a cooler (not shown here) that is acted upon by air, so that the coolant can be cooled. Alternatively, it is possible for the second coolant circuit 40.1 to be connected to a further component of the coolant circuit 11, in which the coolant can give off heat to the coolant.

3 shows a refrigeration system 10, which basically represents an AC function (interior cooling/dehumidification via the evaporator 22 and high-voltage component cooling via the chiller 28) and is expanded to include a heat pump function by expanding the circuitry in the area surrounding the second heat exchanger. The refrigeration system has in addition to the from the 1 and 2 known components a third heat exchanger, in particular chiller 28. The evaporator 22 is associated with an air conditioning device 32 for the interior air conditioning of the motor vehicle, which also applies to the examples of 1 and 2 is applicable. The third heat exchanger 28 is part of a cooling device, not shown, of an electrical drive or storage unit unit of the motor vehicle, in particular the chiller 28 can be used to cool a battery and/or an electric motor. The cooling device is in the 3 represented in simplified form by coolant lines 28.2, in which a coolant, for example a water-glycol mixture, can circulate between the chiller 28 and the electrical component to be cooled.

The evaporator 22 is in all examples 1 until 3 shown as an example as a front evaporator for a vehicle. The evaporator 22 is also representative of other evaporators possible in a vehicle, such as rear evaporators, which can be arranged parallel to one another in terms of flow. In other words, the refrigeration system 10 thus comprises at least one evaporator 22 (provided for the interior air conditioning).

The refrigeration system can optionally have an internal heat exchanger 20 in the 1 until 3 is shown in dashed lines.

The second heat exchanger can be used in a refrigeration system 10 according to FIG 3 as a direct heat exchanger 40 ( 1 ) or as an indirect heat exchanger 40a ( 2 ) to be executed. A bypass section 42 is arranged in the refrigerant circuit 11 so that the cooling off/cooling off or supercooling function can be bypassed if required, in particular when the refrigeration system 10 is in heat pump operation.

The bypass section 42 can, for example, branch off upstream of the second heat exchanger 40, for example at a branch Ab4. At a branch Ab9, the bypass section 42 can again open into the refrigerant circuit 11 or be connected to it. The branch Ab9 is arranged downstream of the second heat exchanger 40 or 40a.

A valve device, in particular a shut-off valve A6, can be arranged between the branch Ab4 and the second heat exchanger 40. A bypass valve device, in particular a bypass shut-off valve A7, can be arranged in the bypass section 42 downstream of the branch Ab4. The flow of refrigerant through the second heat exchanger 40, 40a or the bypass section 42 can be made possible or prevented or (more generally speaking) optionally adjusted by means of the shut-off valves A6, A7. In order to prevent refrigerant from flowing back into the second heat exchanger 40, 40a, a further shut-off valve, designed here as a check valve R6, can be arranged downstream of this and upstream of the branch Ab9. The check valves A6 and A7 can also be combined to form a combination valve, for example a 3-2-way valve.

In a further embodiment, the valve devices A6 and A7 can be designed as a continuously adjustable valve. In this way, in addition to the functional representation of complete blocking or flow, any intermediate positions can also be made possible, which in turn can be used for extended heat management within the process control. Simultaneous flow through both refrigerant lines is made possible with different refrigerant distributions. The second heat exchanger 40 can be provided on the air side with a (continuously) closable or adjustable cooling air inlet 41, which in turn can have a positive effect on the refrigerant distribution, especially at lower ambient temperatures. In this case, a combination of the infinitely variable valves A6 and A7 would correspond to a rotary slide concept, for example.

When the refrigeration system 10 is in heat pump operation, the refrigerant can flow from the refrigerant compressor 12 through the first indirectly acting heat exchanger 18 . The refrigerant is then passed through the bypass section 42 with the bypass shut-off valve A7 open and the shut-off valve A6 closed. From the bypass section 42, the refrigerant in the refrigerant circuit 11 reaches a branch Ab1. Thereafter, depending on the setting of associated expansion valves AE1 or AE2, the refrigerant flows completely or as a partial mass flow into the third heat exchanger or chiller 28 and/or the evaporator 22. The third heat exchanger or chiller can be used as a water heat pump evaporator in order to the coolant circuit 28.2 to absorb heat from the high-voltage components, in particular the electric machine, which is used for heating the cabin air flow. If, for example, the coolant in the coolant circuit is to be heated in order to bring the high-voltage battery to an optimal operating temperature, for example at or shortly after a system start of the refrigeration system 10 when the vehicle is started or at low outside temperatures, for example less than 5°C, the Heat generated via the compressor 12 can be conveyed directly to the chiller 28 without prior delivery at the first heat exchanger 18 . Depending on whether the battery heating process takes place via a right-handed or left-handed triangular process, the chiller 28 can be followed by another expansion element, if necessary, in particular between the chiller 28 and the branch Ab2.

Furthermore, a triangular process with standing water in the chiller 28 can be mapped, so that only the drive power of the compressor 12 that has been converted into heat is transferred to the first heat exchanger trager is delivered, which in turn is connected via a system-side interconnection, not shown, to an interior heat exchanger, in turn positioned within the air conditioning unit 32, for heating the cabin supply air flow.

4 shows a to 3 Similar representation of the refrigeration system 10. This example makes it clear that the second coolant circuit 40.1 can be connected to the coolant circuit 28.2 of the chiller 28. In other words, the chiller 28 and the second (indirect) heat exchanger 40a are integrated in the same coolant circuit 40.1/28.2. In such a configuration, the second heat exchanger 40a is arranged in the coolant circuit 40.1/28.2 in such a way that it is arranged essentially directly after the chiller 28. As a result, coolant is always provided at the second heat exchanger 40a at the lowest possible temperature, in particular the lowest temperature within the coolant circuit. After the coolant has flowed through the second heat exchanger 40a, it reaches the (high-voltage) battery 44 to be cooled before the coolant in the chiller 28 gives off heat to the coolant in the coolant circuit 11 again. Alternatively, a modified connection in the manner of the second heat exchanger 40a to the chiller 28 and then to the high-voltage component 44 is also conceivable.

It is generally pointed out that in the case of an indirect heat exchanger 40a, different coolants can be used, such as, for example, a water-glycol mixture, an oil or another liquid or liquid composition suitable as a coolant.

5 shows an example of a somewhat more complex refrigeration system 10, which has the second, directly or indirectly acting heat exchanger 40 or 40a and the bypass section 42. The refrigeration system 10 also has, in particular, an extended heat pump function and a reheat function. In addition or in addition to the configuration according to the 1 until 4 a check valve A4 is arranged downstream of the compressor 12 . An expansion valve AE2 is provided upstream of the evaporator 22 .

As part of the description of 5 the section from the compressor 12 to the external heat exchanger 18, to the internal heat exchanger 20 and to the evaporator 22 is referred to as the primary line 14 in the entire refrigerant circuit 11 of the refrigeration system 10.

The refrigeration system 10 further includes a heating register 26 (also referred to as a heating condenser or heating gas cooler). A shut-off valve A3 is arranged upstream of the heating register 26 . A shut-off valve A1 is arranged downstream of the heating register 26 . Furthermore, an expansion valve AE4 is arranged downstream of the heating register 26 .

As part of the description of 5 the section from the compressor 12 to the heating register 26, to the expansion valve AE4 and to a branch Ab2 is referred to as the secondary line 16 in the entire refrigerant circuit of the refrigeration system 10. The secondary branch 16 includes a heating branch 16.1, which extends from the shut-off valve A3 via the heating register 26 to the shut-off valve A1. Secondary line 16 also includes an after-heating branch or reheat branch 16.2, which can be fluidly connected to heating register 26 upstream and to external heat exchanger 18 downstream. The secondary line 16 or the reheat branch 16.2 opens into the primary line 14 at a branching point Ab2.

The refrigeration system 10 of 5 can be operated in different modes, which are briefly described below.

In AC operation of the refrigerant circuit 11, the refrigerant compressed to high pressure flows from the refrigerant compressor 12 with the shut-off valve A4 open into the outer heat exchanger 18. From there it flows to the second heat exchanger 40/ 40a for further cooling or subcooling of the refrigerant which is downstream subsequent high-pressure section of the internal heat exchanger 20 and the fully open expansion valve AE3. The refrigerant can flow to the expansion valve AE2 and into the interior evaporator 22 via a branch point Ab1 (evaporator section 22.1). In parallel or alternatively, the refrigerant can flow into the chiller 28 (chiller section 28.1) via a branch point Ab4 and the expansion valve AE1. The refrigerant flows from the evaporator 22 and/or the chiller 28 on the low-pressure side into the collector 24 and through the low-pressure section of the internal heat exchanger 20 back to the compressor 12. For the example of the refrigeration system 10 of FIG 5 a refrigerant collector 24 on the low-pressure side is provided, which is why the collector 19 on the high-pressure side is shown in dashed lines

In AC operation, the heating branch 16.1 or the secondary line 16 is shut off by means of the shut-off valve A3, so that hot refrigerant cannot flow through the heating register 26. To retrieve refrigerant from the inactive heating branch 16.1, the shut-off element A5, which is designed as a shut-off valve, can be opened so that the refrigerant can flow in the direction of the collector 24 via the shut-off element A5 and the non-return valve R2, with the shut-off element A2 being closed at the same time.

In AC operation, refrigerant flows through the second heat exchanger 40, 40a as a cooling/cooling or supercooling section, as already mentioned above for the examples in FIG 1 until 4 has been described. In particular, the shut-off valve A6 is open and the bypass shut-off valve A7 is closed.

In the heating mode of the refrigerant circuit 11, the shut-off valve A4 is closed and the shut-off valve A3 is opened, so that hot refrigerant can flow into the heating branch 16.1.

In order to carry out the heating function by means of the chiller 28 in order to implement water heat pump operation, the refrigerant compressed by means of the refrigerant compressor 12 flows into the heating register 26 via the open shut-off valve A3. At the heating register 26, heat is given off to a supply air flow L guided into the vehicle interior. The refrigerant then flows via the open shut-off valve A1 and the branch point Ab1. It is expanded by means of the expansion valve AE1 in the chiller 28 to absorb waste heat from the electrical and/or electronic components arranged in a coolant circuit 28.2. With this heating function, the expansion valves AE3 and AE4 are closed, the shut-off valve A5 is closed and the shut-off valve A2 is open. In this case, via the shut-off valve A2 during water heat pump operation, refrigerant that has been removed can be sucked out of a bidirectional branch 14.1 or the primary line 14 and fed to the collector 24 via the check valve R2.

To carry out the heating function for the interior of the motor vehicle by means of the first (outer) heat exchanger 18 as a heat pump evaporator, the refrigerant compressed by means of the refrigerant compressor 12 flows via the open shut-off valve A3 to release heat to an inlet air flow L into the heating register 26. It is then discharged via the open check valve A1 relaxed by means of the expansion valve AE3 in the outer heat exchanger 18 for absorbing heat from the ambient air. The refrigerant then flows via a heat pump return branch 15 to the collector 24 and back to the refrigerant compressor 12. The expansion valves AE1, AE2 and AE4 remain closed, as does the shut-off valve A5.

As can be seen from the presentation of 5 results, the refrigerant is passed through the bypass section 42 in this heating function with the first heat exchanger 18 as a heat pump evaporator. The bypass shut-off valve A7 is open and the shut-off valve A6 is closed. A backflow of refrigerant into the second heat exchanger 40, 40a is prevented by the check valve R6.

If the check valve R6 is exchanged for a shut-off valve (not shown), the second heat exchanger 28 can also be integrated in heat pump operation with the opposite flow to AC operation and thereby absorb heat directly from the ambient air. Otherwise, as described, heat is or can be absorbed via the first heat exchanger 18 indirectly via the ambient air or via other components that introduce heat into the coolant circuit 18.1.

An indirect delta connection can be implemented in that, when the shut-off valve A1 is open, the refrigerant compressed by the refrigerant compressor 12 is expanded by means of the expansion valve AE1 into the chiller 28, with no mass flow being generated at the same time on the coolant side, i.e. in the coolant circuit 28.2, i.e. the as Coolant fluid used, such as water or water-glycol mixture, remains on the coolant side of the chiller 28 or the chiller 28 is not actively flowed through by coolant. The expansion valves AE2, AE3 and AE4 remain closed with this switching variant.

In an after-heating or reheat operation, the supply air flow L fed into the vehicle interior is first cooled by means of the evaporator 22 and thus dehumidified. With the heat transferred to the refrigerant by evaporation and dehumidification and the heat supplied to the refrigerant via the compressor 12, the supply air flow L can be completely or at least partially reheated by means of the heating register 26.

For this purpose, the refrigeration system 10, in particular the air conditioning unit 32, between the evaporator 22 and the heating register 26 has adjustable, in particular controllable and pivotable, temperature flaps, which are not shown here in detail.

It is noted that in the 1 until 5 several temperature and/or pressure sensors ptX (X=number) are shown, these serving in particular to be able to detect corresponding temperature and/or pressure values that can be taken into account during operation of the refrigeration system 10 . It is pointed out that the location and/or the number of such sensors can also vary, and here in the 1 until 5 is shown purely as an example.

6 shows a motor vehicle 50 in a schematic and simplified representation, which can have a refrigeration system 10 as described above. The refrigeration system 10 is in the 6 only shown as a simplified dashed rectangle. The directly acting second heat exchanger 40 described above for an example of the refrigeration system 10 can be arranged in such a vehicle 50 in the area of an apron 52 . The apron 52 designates a component which is arranged in the front area or side area of the motor vehicle 50 and is visible from the outside. The second heat exchanger 40 can in particular be arranged behind or in such an apron 52 so that the second heat exchanger 40 is not visible from the outside or is attached to the vehicle 50 so that it is difficult to see. The two dashed rectangles 40 shown purely by way of example and illustratively show possible positions of a second heat exchanger 40, for example at the front of the vehicle 50, for example in the area of a conventional cooler 54 or cooler pack 54, or on the side or at the front of the vehicle 50, for example in the area of air intakes 56 and a fender 58.

The refrigeration system presented here in various examples with a first (external), indirectly acting heat exchanger 18 has the second heat exchanger 40, 40a for further cooling/cooling or Refrigerant subcooling. Optionally, for a refrigeration system 10 with heat pump function ( 3 until 5 ) A bypass section 42 may be arranged so that the second heat exchanger 40, 40a can be bypassed depending on a selected operating state of the refrigeration system 10 or the flow of refrigerant can be prevented or deactivated.

As can be seen from the various examples, the implementation or integration of at least one second heat exchanger 40, 40a is generally conceivable for all refrigerants or all refrigeration circuit variants. The described structure of the refrigeration system 10 can be used for both subcritical and supercritical refrigerants or processes. Furthermore, as described above, it is possible on the one hand to implement this design for systems with a refrigerant reservoir 19 arranged on the high-pressure side and thus to achieve real supercooling of the refrigerant circulating in the system. On the other hand, however, systems with refrigerant reservoirs 24 arranged on the low-pressure side can also benefit from a downstream heat exchanger 40, 40a, which ultimately enables the refrigerant to cool down further and thus allows the overall process to work more efficiently.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102012212227 A1 [0002]
• DE 102017212309 B3 [0003]

Claims (12)

Refrigeration system (10) for a motor vehicle, the refrigeration system (10) comprising: a refrigerant compressor (12); a first, indirectly acting heat exchanger (18) which is arranged downstream of the refrigerant compressor (12) in relation to a flow direction of refrigerant and in which the condensation of refrigerant takes place; at least one evaporator (22) with a valve device (AE2) assigned to the evaporator (22), in particular an assigned expansion valve; characterized in that at least one second, directly or indirectly acting heat exchanger (40) is arranged downstream of the first heat exchanger (18) with respect to the direction of flow of refrigerant in cooling operation of the refrigeration system (10), in which further cooling/cooling or .Subcooling of the refrigerant takes place. Refrigeration system (10) after claim 1 , characterized in that the first indirectly acting heat exchanger (18) is connected to a first coolant circuit (18.1) in which a first coolant circulates, and the second heat exchanger (40) as an indirectly acting heat exchanger (40a) is connected to a second coolant circuit (40.1 ) is connected, in which a second coolant circulates. Refrigeration system (10) after claim 1 or 2 , characterized in that it has at least one third heat exchanger (28), in particular a chiller, which is arranged in flow terms parallel to or in series with the evaporator (22). Refrigeration system (10) after claim 2 and 3 , characterized in that the second coolant circuit (40.1; 28.1) is connected to the third heat exchanger (28), in particular a chiller. Refrigeration system (10) after claim 4 , characterized in that the second coolant circuit (40.1; 28.1) with the second heat exchanger (40a) and the third heat exchanger (28), in particular a chiller, is designed in such a way that the second heat exchanger (40a) is charged with coolant which is essentially has the lowest temperature in the second coolant circuit (40.1; 28.2). Refrigeration system (10) according to one of the preceding claims, characterized in that it has a bypass section (42) in the refrigerant circuit (11) which is set up to bypass the second heat exchanger (40, 40a). Refrigeration system (10) after claim 6 , characterized in that the bypass section (42) between the first heat exchanger (18) and the second heat exchanger (40, 40a) branches off (Ab4) and relative to the flow direction of refrigerant in a cooling operation of the refrigeration system downstream of the second heat exchanger (40, 40a) is connected to the refrigerant circuit (10) (Ab9). Refrigeration system (10) after claim 7 , characterized in that a check valve (R6) is arranged downstream of the second heat exchanger (40, 40a) and upstream of the connection (Ab9) of the bypass section (42) to the refrigerant circuit (11). Refrigeration system (10) after claim 7 or 8th , characterized in that between the branch (Ab4) of the bypass section (42) and the second heat exchanger (40, 40a) a valve device (A6), in particular a shut-off valve, is arranged, which is set up to the refrigerant flow through the second heat exchanger ( 40, 40a) to release or prevent Refrigeration system (10) according to one of Claims 6 until 9 , characterized in that the bypass section (42) has a bypass valve device (A7), in particular a shut-off valve, which is set up to release or prevent the flow of refrigerant through the bypass section (42). Motor vehicle, in particular at least partially electrically driven motor vehicle, with a refrigeration system (10) according to one of the preceding claims. motor vehicle after claim 11 , characterized in that the second heat exchanger (40) as a directly acting heat exchanger (40) in relation to an air flow (UL) is connected upstream of a radiator pack of the motor vehicle or in that the second heat exchanger (409) as a directly acting heat exchanger (40) in the area of an apron of the Motor vehicle is arranged.

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