DE102020130195B3 - Refrigeration system for a motor vehicle for heating an electrical energy store, method for operating such a refrigeration system and motor vehicle with such a refrigeration system - Google Patents

Abstract

A refrigeration system (10) for an at least partially electrically driven motor vehicle is described, the refrigeration system (10) comprising: a refrigerant compressor (12); a directly or indirectly acting external heat exchanger (18); an evaporator (22); a further heat exchanger (28), in particular a chiller, which works as a further evaporator and acts directly or indirectly, which is connected to a coolant circuit (28.2), the coolant circuit (28.2) being connected to at least one energy store (40) for electrical energy for heat exchange; wherein the evaporator (22) and the further heat exchanger (28), in particular the chiller, are arranged parallel to one another, such that refrigerant can be fed to the evaporator (22) and/or the further heat exchanger (28) as desired. It is provided that the refrigeration system (10) is set up to conduct high-pressure, heated refrigerant while omitting the evaporator (22) to the further heat exchanger (28), in particular the chiller, so that the coolant circulating in the coolant circuit (28.2). is heated and serves as a heat source for dissipating heat to the energy store (40). Furthermore, a method for operating such a refrigeration system and a vehicle with such a refrigeration system are described.

Description

The invention relates to a refrigeration system for an at least partially electrically driven motor vehicle, the refrigeration system comprising: a refrigerant compressor; a direct or indirect external heat exchanger; an evaporator and an additional heat exchanger, in particular a chiller, which works as an additional evaporator and acts directly or indirectly, which is connected to a coolant circuit, the coolant circuit being connected to at least one energy store for electrical energy for heat exchange.

From the DE 10 2015 110 571 A1 An air conditioning system for a motor vehicle is known, in which the external heat exchanger, the chiller and the evaporator are necessarily connected in series, which is particularly disadvantageous in the case of high mass flows due to high pressure losses and high amounts of pre-evaporated refrigerant in the chiller, which then reach the evaporator.

More heating and cooling systems for a battery of a motor vehicle are from EP 2 599 651 A1 and the DE 10 2011 114 220 A1 famous.

the DE 10 2019 205 575 A1 discloses a device for temperature control of a vehicle battery in an electric or hybrid vehicle U.S. 2020/0 262 312 A1 discloses a system and method for meeting a thermal management goal for a vehicle component DE 10 2016 118 688 A1 discloses a battery cooling system for a vehicle and the U.S. 2018/0 319 246 A1 discloses a heating system for an electric or hybrid vehicle.

In the case of energy storage devices, in particular high-voltage energy storage devices or high-voltage batteries for motor vehicles, it is known that a maximum charging capacity of a charging station or its maximum charging capacity cannot be achieved, particularly at low ambient temperatures, due to the high internal resistance of the energy storage device. Furthermore, at such ambient temperatures, the maximum currents or drive power cannot be provided even when driving. To make matters worse, the energy store is often heated before the start of a journey or before or during the charging process of the energy store at a charging station.

When using an electrically powered vehicle, this leads in particular to losses in range, comfort and driving characteristics. In addition to known coolant circuits for heating/cooling the energy storage device, as mentioned above, additional high-voltage auxiliary heaters, such as PTC, are also used in the above-mentioned states (before driving, during charging) in which the vehicle is stationary -Resistors that are integrated in the coolant circuit in such a way that the coolant and thus the energy storage device can be heated. Such high-voltage auxiliary heaters are used in particular during the charging process or before the start of a journey, which, however, leads to increased consumption of electrical energy, with electrical energy previously stored in the energy storage device being used again for this purpose, in particular before the start of a journey, which has a direct impact on the affects range.

The object on which the invention is based is seen as specifying an improved and simplified way of heating energy stores for a motor vehicle.

This object is achieved by a refrigeration system, a method for operating this refrigeration system and a motor vehicle with such a refrigeration system according to the respective independent patent claims. Advantageous configurations with expedient developments are specified in the dependent patent claims.

• einen Kältemittelverdichter; einen direkt oder indirekt wirkenden äußeren Wärmeübertrager; einen Verdampfer; einen als weiteren Verdampfer arbeitenden, direkt oder indirekt wirkenden weiteren Wärmeübertrager, insbesondere Chiller, der mit einem Kühlmittelkreislauf verbunden ist, wobei der Kühlmittelkreislauf zum Wärmeaustausch mit wenigstens einem Energiespeicher für elektrische Energie verbunden ist; wobei der Verdampfer und der weitere Wärmeübertrager, insbesondere Chiller, parallel zueinander angeordnet sind, derart dass Kältemittel wahlweise dem Verdampfer oder/und dem weiteren Wärmeübertrager zuführbar ist. Dabei ist vorgesehen, dass die Kälteanlage dazu eingerichtet ist, unter Hochdruck stehendes, erhitztes Kältemittel unter Auslassung des Verdampfers zu dem weiteren Wärmeübertrager, insbesondere Chiller, zu leiten, so dass im Kühlmittelkreislauf zirkulierendes Kühlmittel erwärmt wird und als Wärmequelle zur Abgabe von Wärme an den Energiespeicher dient.

A refrigeration system for an at least partially electrically driven motor vehicle is therefore proposed, the refrigeration system comprising:

• a refrigerant compressor; a direct or indirect external heat exchanger; an evaporator; a further heat exchanger, in particular a chiller, which works as a further evaporator and acts directly or indirectly, which is connected to a coolant circuit, the coolant circuit being connected to at least one energy store for electrical energy for heat exchange; wherein the evaporator and the further heat exchanger, in particular the chiller, are arranged parallel to one another, such that refrigerant can be fed to the evaporator and/or the further heat exchanger as desired. It is provided that the refrigeration system is set up to conduct high-pressure, heated refrigerant to the further heat exchanger, in particular a chiller, while omitting the evaporator, so that the coolant circulating in the coolant circuit is heated and used as a heat source for dissipating heat to the energy store serves.

This makes it possible to use refrigerant at the highest possible temperature and without prior cooling in another heat exchanger, the additional heat exchanger responsible for conditioning the energy store, in particular a chiller, to be able to deliver. The coolant can thus be heated efficiently by means of the refrigeration system without having to use additional high-voltage auxiliary heaters that consume large amounts of electrical energy. The coolant and thus the energy store are heated in particular by means of the refrigeration system or the coolant circuit that is provided in such a vehicle.

The refrigeration system can be set up to adjust the external heat exchanger, which is arranged on the high-pressure side upstream of the additional heat exchanger, in particular a chiller, in such a way that little or no heat is extracted from the refrigerant flowing through the external heat exchanger. In particular, an air supply to the outer heat exchanger can be prevented or suppressed, so that maximum waste heat (from the heated refrigerant) can be provided at the further heat exchanger, in particular the chiller.

Alternatively, the refrigeration system can have at least one line section bypassing the external heat exchanger, which is set up to provide a direct refrigerant flow from the refrigerant compressor to the further heat exchanger, in particular a chiller. In this way, by means of a simple bypass, the refrigeration system can be interconnected in which maximum waste heat (from the heated refrigerant) can be provided at the further heat exchanger, in particular the chiller.

In the refrigeration system, the additional heat exchanger, in particular a chiller, can be arranged in a chiller line section of the refrigeration system, with a respective valve device assigned to the additional heat exchanger being arranged in the chiller line section upstream and downstream of the additional heat exchanger. As a result, the refrigerant flow, which arrives directly from the refrigerant compressor to the further heat exchanger, in particular the chiller, can be adjusted to a desired temperature or pressure level in order to achieve optimum heating of the coolant that heats the energy store.

In this case, the valve device arranged downstream of the additional heat exchanger, in particular a chiller, with respect to the wiring of the refrigeration system and the direction of flow of refrigerant can be an expansion valve. By means of an expansion valve arranged downstream, the hot and high-pressure refrigerant can be expanded to a desired low-pressure level before it is fed back to the refrigerant compressor.

In the refrigeration system, the valve device arranged upstream of the additional heat exchanger, in particular a chiller, with respect to the circuitry of the refrigeration system and the direction of flow of refrigerant can be an expansion valve or a shut-off valve.

In the refrigeration system, in particular a refrigeration system with a heat pump function, the refrigerant compressor can be or can be connected to a primary line and a secondary line, and at least a third heat exchanger representing a heat source, in particular a heating register, can be arranged in the secondary line. In this case, the external heat exchanger can be arranged in the primary line and the evaporator can be arranged in the primary line. Furthermore, a primary branch valve can be arranged between the refrigerant compressor and the external heat exchanger, and a secondary branch valve can be arranged between the refrigerant compressor and the third heat exchanger representing a heat source, in particular a heating coil.

A further shut-off valve can be arranged in the refrigeration system between the primary branch valve and the outer heat exchanger, with a line section of the secondary branch bypassing the outer heat exchanger branching off between the primary branch valve and the further shut-off valve. As a result, a bypass of the external heat exchanger, which has already been described above, can also be provided in a refrigeration system with a heat pump function.

In addition, a check valve can be arranged in the secondary line downstream of the third heat exchanger, in particular the heating register, which prevents refrigerant from flowing back into the third heat exchanger, in particular the heating register, when the secondary line valve is closed, the primary line valve is open and the other shut-off valve is closed.

The refrigeration system can include a control device that is set up to carry out a method described below.

A method for operating a refrigeration system described above is also proposed, the method comprising the following steps: operating the refrigerant compressor,

Adjusting the wiring of the refrigeration system in such a way that a total mass flow of refrigerant is routed under high pressure from the refrigerant compressor to the further heat exchanger, in particular the chiller,
wherein the line between the refrigerant compressor and the further heat exchanger, ins special chillers, arranged external heat exchangers or third heat exchangers, in particular heating registers, are adjusted in such a way that the heat emission to a medium flowing through the relevant heat exchanger, in particular air, is minimized; or
valve devices of the refrigeration system being set in such a way that the flow of refrigerant is routed past the external heat exchanger or the third heat exchanger, in particular a heating register.

Other optional process features can be derived from the structural and functional features of the refrigeration system described above. In particular, this also includes method steps for setting valve devices.

A motor vehicle, in particular an at least partially electrically operated motor vehicle, can have a refrigeration system as described above. In an electric vehicle, the efficient operation of the refrigeration system can lead to electricity savings, so that a greater range of the electric vehicle can be achieved as a result. In particular, the energy store can be kept at a temperature level by the refrigeration system presented here that enables optimal storage and release of electrical energy.

• 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 ein vereinfachtes Diagramm eines Verfahrens zum Betrieben einer Kälteanlage.

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 simplified diagram of a method of operating a refrigeration system.

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). In the embodiment shown, the refrigeration system 10 comprises a refrigerant compressor 12, an external heat exchanger 18, an internal heat exchanger 20, an evaporator 22 and an accumulator or refrigerant collector 24. The external heat exchanger 18 can be designed as a condenser or gas cooler.

The evaporator 22 is shown here by way of 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 includes at least one evaporator 22.

The refrigeration system 10 includes a further heat exchanger, in particular an evaporator or chiller 28 . The chiller 28 is provided parallel to the evaporator 22 in terms of flow. The chiller 28 can be used, for example, to cool an electrical component, in particular an electrical energy store 40 (for example a high-voltage battery, shown only schematically here), of the vehicle, but also to implement a water heat pump function using the waste heat from at least one electrical component. An expansion valve AE1 is connected upstream of the chiller 28 . The electrical components or the electrical energy store 40 can be connected to the chiller 28 by means of a coolant circuit 28.2 for heat exchange.

The further heat exchanger, in particular the chiller 28, is arranged in a chiller line section 28.1 of the refrigerant circuit 11. The chiller line section 28.1 extends here, for example, between a branch Ab4 and a branch Ab2. An expansion valve AE1, AE5 is arranged upstream and downstream of the additional heat exchanger 28 (chiller).

The refrigeration system 10 can also have an electrical heating element 30 which is designed, for example, as a high-voltage PTC heating element. The electric heating element 30 is used as an additional heater for a supply air flow L guided into the vehicle interior. The electric heating element 30 can be accommodated together with the evaporator 22 in an air conditioning unit 32 . In this case, the electrical heating element 30 can be arranged downstream of the evaporator 22 .

It is pointed out that the following description of the refrigerant flow for warming up or heating the energy store 40 is shown in each case with corresponding arrow symbols (>) along the refrigerant circuit 11 in the figures. It is further 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 position and/or the number of such sensors can also vary, and here in the 1 until 5 is shown purely as an example.

For the heating of the energy store 40, the refrigeration system 10 can 1 be set as follows. The refrigerant is compressed and heated in the refrigerant compressor 12 . The refrigerant flows to the external heat exchanger 18, which or the environment thereof is set in such a way that air does not actively flow through it. As a result, little or no heat is extracted from the heated refrigerant in the external heat exchanger 18 . The refrigerant flows under high pressure through the external heat exchanger 18.

When the expansion valve AE2 is closed, the entire mass flow of refrigerant is routed through the expansion valve AE1, which is open without loss. The refrigerant then arrives under high pressure and is heated in the additional heat exchanger 28 (chiller). In the chiller 28, heat is then given off to the coolant in the coolant circuit 28.2. The coolant heated in this way circulates in the coolant circuit 28.2 to the energy store 40 and warms or heats it.

It should be noted that for the coolant to flow through the chiller 28 under high pressure, the latter must be designed accordingly mechanically and, of course, also thermally.

The expansion valve AE5 is arranged downstream of the chiller 28 in the chiller line section 28.1. The refrigerant exiting from the chiller 28 can be expanded to a low-pressure level by means of the expansion valve AE5. The refrigerant then returns to the refrigerant compressor 12. By means of the in 1 In the refrigeration system 10 shown, it is thus possible to simply warm up or heat the energy store 40 without having to provide additional electrical heaters on the energy store 40 itself or along the coolant circuit 28.2.

In this exemplary type of process management, the heat for the high-voltage storage device is obtained by operating the refrigeration system 10 as a triangular process. Only the drive power of the compressor 12 that has been converted into heat is used for heat generation.

As an alternative to the left-hand triangular process described above, in which the chiller 28 is charged with refrigerant under high pressure, a clockwise triangular process can also be used in which the chiller 28 is charged with refrigerant at reduced medium or low pressure. In this case, AE5 is dispensed with and the refrigerant coming from the compressor 12 is expanded directly into the chiller 28 via the expansion element AE1. The use of the chiller 28, which is still designed as a low-pressure component, is particularly advantageous. However, the refrigerant temperatures to be expected at the inlet of the chiller 28 are lower than in the left-hand process, since the isotherms in the area of overheated refrigerant within the Ig p,h diagram do not run vertically and as a result, heat losses are recorded via the expansion.

2 shows another refrigeration system 10, in which refrigerant can get from the refrigerant compressor 12 to the chiller 28, bypassing the external heat exchanger 18 of refrigerant in the external heat exchanger 18 can be blocked or released. Starting from a branch Ab3, a bypass section 18.2 is provided, in which a shut-off valve A2 is arranged. In the case of a branch Ab6, a line section 18.3 on the output side and the bypass section 18.2 are connected to one another. In the line section 18.3 on the outlet side, a valve fulfilling a shut-off function, shown here as a check valve R6, is arranged.

When the shut-off valve A2 is open and the shut-off valve A6 is closed, the heated refrigerant can flow via the bypass section 18.2 from the refrigerant compressor 12 to the chiller 28, bypassing the external heat exchanger 18. With this setting of the shut-off valves A2 and A6, heating can therefore take place of the energy store 40 take place, with the above explanations for downstream of the external heat exchanger 18 or of the branch Ab6 1 apply analogously.

Alternatively, the two valves A2 and A6 can be combined in a 3-2-way valve (not shown) and this can be arranged in the branch point Ab3.

3 shows another configuration of a refrigeration system 10, in which the refrigerant can get from the refrigerant compressor 12 to the chiller 28, bypassing the external heat exchanger 18, but also including the external heat exchanger 18. For this purpose, in an input-side line section 18.1 between the refrigerant dense 12 and the outer heat exchanger 18, a shut-off valve A6 may be provided so that - depending on the situation - the inflow of refrigerant into the outer heat exchanger 18 can be blocked or released. Starting from a branch Ab3, a bypass section 18.2 is provided, in which a shut-off valve A2 is arranged. The bypass section 18.2 extends from the branch Ab3 to the branch Ab4.

In addition, another check valve R3 (shown in broken lines) can be positioned in this bypass section 18.2 upstream of the branching point Ab4, in order to avoid refrigerant relocation for certain system operating states. In the case of an inactive system section 18.2, refrigerant can be sucked off via a connecting line (not shown) to the low-pressure side of the refrigeration circuit 10, which in turn has a controllable shut-off device.

When the shut-off valve A2 is open and the shut-off valve A6 is closed, the heated refrigerant can flow from the refrigerant compressor 12 to the chiller 28 via the bypass section 18.2, bypassing the external heat exchanger 18. Optionally, a check valve R2 can be provided to prevent refrigerant transfers, which can be installed upstream, for example from branch Ab4. Here, too, the two shut-off valves A2 and A6 can be brought together in a 3-2-way valve, which can be arranged in the branching point Ab3.

In general, it should be noted that the combination of individual valves, such as A2 and A6, to form multi-way valves reduces the number of separately designed components and increases the compactness of the system, thereby reducing the space required.

Even with a configuration of the refrigeration system 10 according to FIG 3 the heating or heating of the energy store 40 works as it were via a triangular process involving or bypassing the external heat exchanger 18. The shut-off valve A6 is open and the shut-off valve A2 is closed. With such a connection, the heated refrigerant flows in a manner similar to that for the 1 described, to the outer heat exchanger 18, which is set so that it is not actively flowed through by air. As a result, little or no heat is extracted from the heated refrigerant in the external heat exchanger 18 . The refrigerant flows under high pressure through the external heat exchanger 18. Downstream of the external heat exchanger 18, the above statements apply 1 analogous.

Alternatively, the shut-off valve A2 is open and the shut-off valve A6 is closed and the refrigerant flows from its surroundings via the line section 18.2 to the chiller 28 without absorbing heat.

4 shows a further configuration of a refrigeration system 10, in which refrigerant can reach the chiller 28 from the refrigerant compressor 12, bypassing the external heat exchanger 18. In the configuration of 4 both the outer heat exchanger 18 and the further heat exchanger 28 (chiller) can be flown through in both directions.

In this configuration, the bypass section 18.2 extends from the branch Ab3 to a branch Ab7. In the case of branch Ab7, the bypass section 18.2 and the chiller line section 28.1 are connected to one another. In other words, it can also be said that a chiller line section is formed between the branch Ab3 and the branch Ab4. Incidentally, the refrigeration system 10 is the 4 constructed the same as that of 1 .

The heated refrigerant can flow from the refrigerant compressor 12 to the chiller 28 via the bypass section 18.2 when the shut-off valve A2 is open and the shut-off valve A6 is closed, bypassing the external heat exchanger 18 1 until 3 the heated refrigerant based on the figures from the left flows into the chiller 28 is in the configuration of 4 the direction of flow is reversed. The refrigerant flows into the chiller 28 from the right-hand side. The expansion valve AE5 is closed. The refrigerant then flows downstream of the chiller 28 through the expansion valve AE1, which is set in such a way that a desired expansion of the refrigerant in the external heat exchanger 18 is achieved. The expansion valve AE2 is closed in this configuration. After the external heat exchanger 18, the refrigerant then flows via the open shut-off valve A7 to the low-pressure side of the refrigerant circuit 11 and back to the refrigerant compressor 12. The system can according to FIG 4 be operated as an air heat pump in the event that the external heat exchanger 18 is actively flowed through with ambient air. Alternatively, with an external heat exchanger that is not subjected to air, the system can function as a triangular process.

With this setting of the shut-off valves A2 and A6, the energy store 40 can be heated or heated, with the refrigerant in the refrigerant circuit between the branch Ab3 and the branch Ab2 having a different flow direction than in the examples described above 1 until 3 .

5 shows a further configuration of a refrigeration system 10, which in particular also has a heat pump function. In addition or in addition to the configuration according to the 1 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 also includes a third heat exchanger, in particular 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 Ab6 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 Ab6.

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 when the shut-off valve A4 is open into the outer heat exchanger 18. From there it flows to the high-pressure section of the inner 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.

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 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 check valve R2, with the shut-off element A2 being closed at the same time.

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 external heat exchanger 18 as a heat pump evaporator, the refrigerant compressed by 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 released via the open shut-off valve A1 expanded by means of the expansion valve AE3 in the outer heat exchanger 18 to absorb 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.

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 into the chiller 28 by means of the expansion valve AE1, 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.

In the 5 Refrigeration system 10 shown can, as already mentioned above for the other refrigeration systems 10 of 1 until 4 described, used or set up to heat the energy store 40 or to heat. In this case, the so-called reheat branch 16.2 as above for the 2 and 3 bypass section 18.2 described can be used. So that refrigerant from the refrigerant compressor 12 reaches the further heat exchanger or chiller 28 under high pressure and is heated, the primary branch valve A4 is opened, while the secondary branch valve A3 is closed. Furthermore, the shut-off valves A6 and A2 are closed, so that the refrigerant flows at the branch Ab6, bypassing the external heat exchanger 18, in the direction of the chiller 28. In this case, the expansion valve AE4 present in the reheat branch 16.2 is fully open. When the shut-off valve 1 is open, the expansion valve AE1 is open and the expansion valves AE2 and AE3 are closed, the refrigerant is routed to the chiller 28 . Downstream of the chiller 28, expansion to low pressure takes place by means of the expansion valve AE5, so that the refrigerant can be fed back to the refrigerant compressor 12.

With this setting of the shut-off valves A2, A3, A4 and A6, the energy store 40 can be heated or heated, with the refrigerant in the refrigerant circuit between the branch Ab6 and the branch Ab4, i.e. in the reheat branch 16.2 used as a bypass section, a has a different direction of flow than in a reheat or heat pump operation of the refrigeration system 10 described above 5 . In order to enable such an operation of the refrigeration system 10, it is also useful to prevent refrigerant from flowing back into the heating register by using a check valve R5. The refrigerant flow for this circuit is in the 5 shown with arrow symbols (>).

Alternatively, the refrigeration system 10 of 5 for heating the energy accumulator 40 can also be operated as follows, in which case the shut-off valve A6 and the check valve R5 can be omitted. In that regard, the check valve A6 and the check valve R5 represent optional components of the refrigeration system 10. The refrigerant flow for this circuit is not in the 5 shown explicitly, but is only described below.

Starting from the refrigerant compressor 12, the secondary branch valve A3 is opened and the primary branch valve is closed. The refrigerant flows through the heating coil 26, the fully open valves A1 and AE1 to the chiller 28. The expansion valves AE3 and AE4 are closed. Accordingly, there is high pressure in the heating register 26 and in the chiller 28 and low pressure after the expansion valve AE5 (downstream of the chiller 28). In order to be able to provide coolant that is as hot as possible at the chiller 28, care is also taken with this connection that the heating register 26 is not charged with air for heating interior air.

A further alternative connection of the refrigeration system 10 can appear as follows, with this connection also not requiring a shut-off valve A6 and a check valve R5. The refrigerant flow for this circuit is not in the 5 shown explicitly, but is only described below. The primary branch valve A4 is open and the secondary branch valve A3 is closed. The refrigerant flows from the refrigerant compressor 12 to the outdoor heat exchanger 18, which is not acted upon by air, as already mentioned above with reference to FIG 1 has been described. The refrigerant then continues to flow under high pressure through the open valves AE3 and AE1, with the valves A1 and AE2 being closed. Thus, even with this connection, the refrigerant reaches the chiller 28 under high pressure and is heated. The expansion to low pressure takes place again through the expansion valve AE5 downstream of the chiller 28.

In general, be with everyone 1 until 5 the option also mentioned of dispensing with the expansion element AE5 downstream of the chiller 28 and of changing to a clockwise instead of the counterclockwise process control or triangular processes described above. In this case, high pressures no longer occur in the chiller 28 since the expansion element AE1 connected upstream of it expands the refrigerant before it flows through the chiller 28 . This is also associated with temperature losses or losses, which - depending on the course of the isotherms in the gaseous section of the Igp,h diagram of the refrigerant used in each case - can be more or less severe. Ideally, these run vertically, so there is no temperature loss associated with the expansion of the refrigerant. The heat is released in the usual way in the chiller 28 before the refrigerant flows on to the compressor 12 .

A method 500 by means of one of the refrigeration systems 10 described above 1 until 5 can be implemented is simplified in 6 shown. The method 500 for operating a refrigeration system 10 described above comprises the following steps. According to step S501, the refrigerant compressor 12 is operated. In a step S502, the interconnection of the refrigeration system 10 is set such that a total mass flow of refrigerant is conducted under high pressure from the refrigerant compressor 12 to the additional heat exchanger 28, in particular the chiller. According to step S503, the external heat exchanger 18 or third heat exchanger 26, in particular heating register, arranged in the line path between the refrigerant compressor 12 and the further heat exchanger 28, in particular a chiller, is set in such a way that the heat is released to a medium flowing through the heat exchanger 18, 26 in question, especially air, is minimized. Alternatively, according to step S504, valve devices, for example the valves A2, A6, of the refrigeration system 10 can be set in such a way that the refrigerant flow is routed past the external heat exchanger 18 or the third heat exchanger 26, in particular a heating register, depending on which flow paths via the present one system interconnection are possible.

As can be seen from the above descriptions of the refrigeration systems 10 of 1 until 5 readily follows, optional steps for the method for operating the refrigeration system 10 can also be derived from the functional or structural features described there, which are described in 6 are indicated as dashed rectangles. In particular, the method can also have steps, such as opening or closing certain valve devices, detecting other operating parameters, such as the ambient temperature. In that regard, the method is not only limited to the above main steps, but it can also have additional steps that can be derived from the context of the description of the above refrigeration systems 1 until 5 result.

Claims (11)

Refrigeration system (10) for an at least partially electrically driven motor vehicle, the refrigeration system (10) comprising: a refrigerant compressor (12); a directly or indirectly acting external heat exchanger (18); an evaporator (22); a further heat exchanger (28), in particular a chiller, which works as a further evaporator and acts directly or indirectly, which is connected to a coolant circuit (28.2), the coolant circuit (28.2) being connected to at least one energy store (40) for electrical energy for heat exchange; the evaporator (22) and the further heat exchanger (28), in particular the chiller, being arranged parallel to one another in such a way that refrigerant can be fed to the evaporator (22) and/or the further heat exchanger (28), characterized in that the refrigeration system ( 10) is set up to conduct high-pressure, heated refrigerant, leaving the evaporator (22) to the further heat exchanger (28), in particular the chiller, so that the coolant circulating in the coolant circuit (28.2) is heated and used as a heat source for discharging Heat to the energy storage device (40) is used. Refrigeration system (10) after claim 1 , characterized in that it is set up to adjust the external heat exchanger (18), which is arranged on the high-pressure side upstream of the further heat exchanger (28), in particular the chiller, in such a way that the refrigerant flowing through the external heat exchanger (18) hardly or no heat is extracted. Refrigeration system (10) after claim 1 , characterized in that it has at least one line section (18.2) surrounding the outer heat exchanger (18), which is set up to provide a direct refrigerant flow from the refrigerant compressor (12) to the further heat exchanger (28), in particular the chiller. Refrigeration system (10) according to one of the preceding claims, characterized in that the further heat exchanger (28), in particular a chiller, is arranged in a chiller line section (28.1) of the refrigeration system (10), with upstream and downstream of the further heat exchanger (28) a respective valve device (AE1) assigned to the further heat exchanger (28), AE5) is arranged in the chiller line section (28.1). Refrigeration system (10) after claim 4 , characterized in that the valve device arranged downstream of the further heat exchanger (28), in particular the chiller, with respect to the wiring of the refrigeration system (10) and the direction of flow of refrigerant is an expansion valve (AE1, AE5). Refrigeration system (10) after claim 4 or 5 , characterized in that the valve device arranged upstream of the further heat exchanger (28), in particular the chiller, with respect to the wiring of the refrigeration system (10) and the direction of flow of refrigerant is an expansion valve (AE1) or a shut-off valve (A2, A3). . Refrigeration system (10) according to one of the preceding claims, characterized in that the refrigerant compressor (12) can be connected or is connected to a primary line (14) and a secondary line (16), and that in the secondary line (16) at least a third, a heat source representative heat exchanger (26), in particular a heating register, is arranged, the outer heat exchanger (18) being arranged in the primary line (14); wherein the evaporator (22) is arranged in the primary line (14); a primary branch valve (A4) being arranged between the refrigerant compressor (12) and the external heat exchanger (18); and wherein a secondary branch valve (A3) is arranged between the refrigerant compressor (12) and the third heat exchanger (26) representing a heat source, in particular a heating register (26). Refrigeration system (10) after claim 7 , characterized in that a further shut-off valve (A6) is arranged between the primary line valve (A4) and the outer heat exchanger (18), with a line section bypassing the outer heat exchanger (18) between the primary line valve (A4) and the further shut-off valve (A6). (16.2) of the secondary strand (16) branches off. Refrigeration system (10) after claim 8 , characterized in that a check valve (R5) is arranged in the secondary line (16) downstream of the third heat exchanger (26), in particular a heating register, which prevents refrigerant from flowing back into the third heat exchanger (26), in particular a heating register, if the Secondary branch valve (A3) is closed, the primary branch valve (A4) is open and the other shut-off valve (A6) is closed. Method (500) for operating a refrigeration system (10) according to one of the preceding claims, the method comprising the following steps: operating (S501) the refrigerant compressor (12); Adjusting (S502) the interconnection of the refrigeration system (10) in such a way that a total mass flow of refrigerant is routed under high pressure from the refrigerant compressor (12) to the further heat exchanger (28), in particular the chiller, wherein the external heat exchanger (18) or third heat exchanger (26), in particular a heating register, arranged in the line path between the refrigerant compressor (12) and the additional heat exchanger (28), in particular the chiller, is adjusted (S503) such that the heat output to a den the medium flowing through the relevant heat exchanger (18, 26), in particular air, is minimized, or wherein valve devices (A2, A6) of the refrigeration system (10) are set so that the coolant flow is routed past the external heat exchanger (18) or the third heat exchanger (26), in particular a heating register. Motor vehicle, in particular at least partially electrically driven motor vehicle, with a refrigeration system (10) according to one of Claims 1 until 9 .

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