CN108332455B

CN108332455B - Refrigerant circuit and method for operating a refrigerant circuit

Info

Publication number: CN108332455B
Application number: CN201810026548.1A
Authority: CN
Inventors: 彼得·海尔; 费利克斯·吉尔姆沙伊德
Original assignee: Hanon Systems Corp
Current assignee: Hanon Systems Corp
Priority date: 2017-01-13
Filing date: 2018-01-11
Publication date: 2021-02-02
Anticipated expiration: 2038-01-11
Also published as: KR102020930B1; DE102017100591B3; CN108332455A; KR20180083791A

Abstract

The invention relates to a refrigerant circuit, in particular for a motor vehicle having an electric or hybrid drive, wherein a condenser (3), an expansion mechanism (5), a separator (6) as a medium-pressure bottle, and an expansion mechanism (7) are provided in series in the refrigerant flow direction, and subsequently a battery cooler (11) and an air cooler (12) are arranged in a parallel connection, whereby a primary compressor (1) and a secondary compressor (2) are arranged in parallel lines, wherein the high-pressure side of the main compressor (1) is connected with the suction side of the auxiliary compressor (2), so that the main compressor (1) and the auxiliary compressor (2) can be connected in series or in parallel by means of a shut-off mechanism (18) and a multi-way valve (16) in the high-pressure line of the main compressor (1), and the separator (6) is connected on the gas side with the suction side of the secondary compressor (2). The invention also relates to a method for operating a refrigerant circuit.

Description

Refrigerant circuit and method for operating a refrigerant circuit

Technical Field

The present invention relates to a refrigerant circuit for a motor vehicle, which has a particularly high refrigeration capacity compared to conventional refrigeration circuits of this type. The refrigerant circuit is particularly useful for motor vehicles having an electric or hybrid drive. A special feature in such refrigerant circuits is that, in particular in electric vehicles or hybrid vehicles, cooling of the battery or accumulator and of the electronic components and additionally cooling of the vehicle interior for air conditioning are necessary in order to achieve optimum conditions in driving operation and in charging operation of the battery. The need for rapid charging of the battery in particular creates a special requirement for cooling installations of motor vehicles, since optimal charging of the battery is associated with cooling of the battery during the charging process.

Background

Different embodiments of refrigerant circuits for motor vehicles with electric or hybrid drives are known from the prior art.

In the prior art, a refrigeration device with a bypass for a motor vehicle is known, for example from US 2009/0317697 a1, which is suitable for providing battery cooling by means of a battery cooler.

Furthermore, DE 10313850 a1 discloses a refrigerant circuit for combined refrigeration and heat pump operation, in particular for motor vehicles, having a two-stage compression device. In this refrigerant circuit, two compressors are provided which are connected in series and which effect a two-stage compression, the circuit being optimized in order to also be able to perform the heat pump operation of the entire installation.

Disclosure of Invention

The object of the present invention is to provide a refrigerant circuit, in particular for a motor vehicle having an electric or hybrid drive, which is suitable for optimally cooling the battery and the electronic components during driving operation and during charging operation of the battery, in addition to the purpose of cooling the vehicle cabin for air conditioning.

The object of the invention is to achieve as many operating states as possible, such as driving operation, charging operation and heat pump operation, by means of the line connections of the components provided in the circuit.

The object is achieved by a refrigerant cycle and a method, in which, a condenser, an expansion mechanism, a separator as a medium pressure bottle, and an expansion mechanism are provided in series in the refrigerant flow direction, and then a battery cooler and an air cooler are provided in parallel connection, whereby a main compressor and an auxiliary compressor are provided in parallel lines, wherein the high-pressure side of the main compressor is connected with the suction side of the secondary compressor, such that the main compressor and the secondary compressor can be connected in series or in parallel by means of a shut-off mechanism and a multi-way valve in the high-pressure line of the main compressor, and the separator is connected on the gas side with the suction side of the secondary compressor, and in the method, in a charging operation of the battery, the refrigerant is compressed in two stages in the main compressor and in the sub-compressor; subsequently flowing the refrigerant through a condenser to dissipate heat; depressurizing the refrigerant in an expansion mechanism to an intermediate pressure; drawing a gas phase of the refrigerant through the secondary compressor; and the liquid phase of the refrigerant is evaporated in the battery cooler and sucked through the primary compressor, or in a single-stage heat pump operation, the refrigerant is compressed in the primary compressor in single stages; subsequently flowing the refrigerant through a condenser to effect heat dissipation to the vehicle interior space; depressurizing the refrigerant in an expansion mechanism to an intermediate pressure; drawing a gaseous phase of the refrigerant through the primary compressor; and the liquid phase of the refrigerant is evaporated in the heat pump heat exchanger and sucked in by the primary compressor, or in a two-stage heat pump operation, the refrigerant is compressed in the primary compressor and in the secondary compressor in two stages; subsequently flowing the refrigerant through a condenser to effect heat dissipation to the vehicle interior space; depressurizing the refrigerant in an expansion mechanism to an intermediate pressure; drawing a gas phase of the refrigerant through the secondary compressor; and the liquid phase of the refrigerant is simultaneously evaporated in the heat pump heat exchanger, in the air cooler and in the battery cooler and drawn in by the primary compressor. The modifications are given below.

The object of the invention is achieved in particular by a refrigerant circuit which is optimized specifically for motor vehicles having an electric or hybrid drive. Here, the refrigerant circulation circuit is indicated by the arrangement of the following components in the refrigerant flow direction. The refrigerant first flows through the condenser, then through the expansion device, then through the separator, which is also referred to as a medium-pressure bottle in two-stage operation, and as an accumulator, refrigerant separator or receiver in single-stage operation, and through the further expansion device. The mentioned components are arranged in series. Next, the refrigerant flows through as heat transfer devices for the evaporator, i.e., a battery cooler and an air cooler, which are arranged in parallel. After flowing through the battery cooler and the air cooler, the refrigerant is drawn in as refrigerant vapor by the main compressor. In addition to the primary compressor, a secondary compressor is provided in the refrigerant circulation circuit. The main compressor and the auxiliary compressor are connected in parallel to one another in the circulation circuit, wherein a closable connection to the suction side of the auxiliary compressor is provided downstream of the main compressor, so that the main compressor and the auxiliary compressor can be connected both in parallel and in series. For this purpose, a shut-off mechanism is provided in the high-pressure line of the main compressor and a multi-way valve is provided in the connection between the main compressor line and the secondary compressor line.

The separator here usually has an inlet for the liquid-gas-refrigerant mixture and an outlet for the gas and an outlet for the liquid. The outlet of the separator for the gas is also referred to as the gas side and this gas side is connected to the suction side of the secondary compressor.

The described components and the described parallel and series connection possibilities of the primary and secondary compressors are particularly advantageously suitable for achieving various operating states, which are suitable for use in particular in electric or hybrid vehicles, since different operating states can be achieved by means of the described refrigerant circuit.

Preferably, the shut-off mechanism is provided in a connection of the gas side of the separator and the suction side of the secondary compressor.

Advantageously, the expansion means are associated independently with the battery cooler and the air cooler, respectively. Each heat exchanger can then be controlled independently and in coordination with the overall system with regard to regulation and taking into account the specific pressure drop of the heat exchanger.

Advantageously, an additional coolant circuit is formed, which has a pump, a heat pump heat exchanger and a coolant air cooler, wherein the heat pump heat exchanger is arranged in parallel with the battery cooler and the air cooler in the coolant circuit with the associated expansion means. Water or a water-glycol mixture is preferably used as the coolant, so that the coolant-air cooler is also referred to as a water-air cooler. Coolant-air coolers are also referred to as low-temperature heat exchangers or as high-temperature heat exchangers in relation to their temperature ranges of use.

According to a particularly preferred embodiment of the invention, the additional condenser is connected in the coolant circuit and in the refrigerant circuit, alternatively or cumulatively (kumulativ), via a multi-way valve. The additional condenser is disposed downstream of the condenser in a refrigerant flow direction in the refrigerant circulation circuit.

A particularly preferred design of the circuit results when the secondary compressor is integrated into the main compressor, and the main compressor is configured as a two-stage compressor.

The object of the invention is also achieved by a method for operating a refrigerant circuit, wherein in an air conditioning mode during driving operation, refrigerant is first compressed in a single stage in a main compressor, then flows through a condenser for heat dissipation, and is then reduced in pressure in an expansion device to an intermediate pressure. The gaseous phase of the refrigerant is then sucked in the separator by the main compressor, throttled according to the pressure level in the suction line into the compressor, or fed to the compressor in accordance with the pressure level, and finally the liquid phase of the refrigerant is evaporated simultaneously in the air cooler and the battery cooler and then sucked in by the main compressor. In this mode, the refrigerant cycle circuit operates in a single stage and the secondary compressor is inactive. The refrigeration capacity of the refrigeration circuit connected in this way corresponds to the conventional refrigeration capacity of a motor vehicle air conditioning system.

In a single-stage process, alternatively, no depressurization takes place upstream of the separator, so that an expansion device with a complete flow cross section is added upstream, without throttling the refrigerant.

Advantageously, the refrigerant is depressurized upstream of the air cooler and the battery cooler, respectively, independently by means of expansion means, which are associated with the respective heat exchanger.

The object of the invention is also achieved by a method for operating a refrigerant circuit, wherein in a charging operation of a battery, refrigerant is first compressed by a primary compressor and a secondary compressor connected in series, and the refrigerant is compressed in two stages. Subsequently, the refrigerant is passed through the condenser to dissipate heat, and then the refrigerant is depressurized to an intermediate pressure in the expansion mechanism. The gaseous phase of the refrigerant is drawn in the circuit by the secondary compressor and the liquid phase of the refrigerant is evaporated in the battery cooler and drawn in by the primary compressor. In this operating mode of the exclusive charging operation, the air cooler is deactivated, so that all cooling capacity and cooling power can be used for the charging operation and in particular for the rapid charging operation. It goes without saying that, alternatively, the cooling power can be used for air conditioning of the vehicle interior space to reduce the charging cooling power.

It is particularly advantageous to assist the heat removal of the refrigerant in addition to the condenser by means of an additional condenser connected downstream in series of the refrigerant circuit.

The object of the invention is also achieved by a method for operating a refrigerant circuit, wherein a refrigerant is compressed in a single stage in a primary compressor in a single-stage heat pump operation, then said refrigerant flows through a condenser in order to dissipate heat to a vehicle interior and is reduced in pressure in an expansion device to an intermediate pressure. Finally, the liquid phase of the refrigerant is evaporated in the heat pump heat exchanger by the vapor phase suction of the refrigerant of the main compressor and sucked in by the main compressor, thereby closing the circulation circuit. This mode of operation is particularly advantageous if the heat requirement is relatively small.

The object of the invention is also achieved by a method for operating a refrigerant circuit, wherein in a two-stage heat pump operation the refrigerant is compressed both in the primary compressor and in the secondary compressor, and thus the refrigerant is compressed in two stages. The refrigerant is then passed through a condenser to dissipate heat to the vehicle interior space. In the expansion mechanism, the refrigerant is depressurized to an intermediate pressure and a gas phase of the refrigerant is drawn in through the sub-compressor. The liquid phase of the refrigerant is simultaneously evaporated in the heat pump heat exchanger, in the air cooler and in the battery cooler and drawn in by the main compressor. In this type of operation, a particularly high proportion of the heat is supplied to the vehicle interior via the heat pump function.

Particularly preferably, the heat pump system according to the aforementioned variant is improved in the following way: in addition, heat absorption of the refrigerant in the heat pump heat exchanger takes place from the coolant circuit, wherein the coolant circuit in the heat pump heat exchanger is thermally coupled to the refrigerant circuit. In the operation of the refrigeration system, a water condenser is connected in the coolant circuit.

The aforementioned method is advantageously improved by: the additional heat transfer surface is not used exclusively during the charging operation of the battery for the purpose of dissipating heat in the battery cooler.

The method is likewise advantageously improved in the following manner: the additional heat transfer surface is not used exclusively during charging operation for heat dissipation in the coolant air cooler, or the entire surface can be used by other components since it is not used.

Preferably, the method is supplemented by: the additional heat transfer surface is switched off, which is used exclusively for heat dissipation in the condenser during charging operation, or the power at the constant condenser is implemented at a higher pressure as a driving temperature difference.

Drawings

Further details, features and advantages of the design according to the invention result from the following description of an embodiment with reference to the drawing. The figures show:

FIG. 1 shows a refrigerant cycle circuit with two compressors;

FIG. 2 shows a refrigerant cycle circuit with two compressors and a medium pressure gas line that can be shut off;

FIG. 3 shows a refrigerant circulation circuit in combination with a coolant circulation circuit;

fig. 4 shows a functional diagram of a two-stage design of a refrigerant circuit in heat pump operation;

FIG. 5 shows a refrigerant cycle circuit with a battery cooler at a medium pressure level; and

fig. 6 shows a refrigerant circuit with a battery cooler at a low pressure level and an optional gas feed at a low or high pressure level.

Detailed Description

Fig. 1 shows a design of a refrigerant circuit, which describes the basic principle with the aid of the components involved. The main compressor 1 and the auxiliary compressor 2 are added to the refrigerant circuit not only for operation when connected in series but also for operation when connected in parallel by means of the multi-way valve 16 and the blocking mechanism 18. The refrigerant circulation circuit has, at a high pressure level, a condenser 3 and an expansion mechanism 5 and a separator 6 connected downstream in series in the flow direction. The separator 6 is also referred to as a medium pressure bottle, as long as the two-stage operation is performed at a medium pressure level of the refrigerant. If a single-stage compression is carried out, the function of the separator 6 is reduced to an accumulator for liquid refrigerant downstream of the first expansion stage via the expansion means 5, or the expansion means 5 operates with a fully open cross section and an expansion is effected via the expansion means 7. The refrigerant vapor phase leaving the separator 6 at medium or high pressure reaches the suction side of the secondary compressor 2 via a line. The liquid refrigerant from the separator 6 is reduced in pressure in the expansion device 7 to a low pressure and then distributed to the consumers, the battery cooler 11 and the air cooler 12 simultaneously. The evaporated refrigerant from the heat exchanger is then jointly fed to the suction side of the main compressor 1. As long as the circuit is operated in a single stage, as will be described in more detail below, the shut-off mechanism 18 for the high-pressure gas of the main compressor 1 is opened and the compressed refrigerant passes directly into the condenser 3. If a plant with

compressors

1, 2 connected in series is operated, the shut-off mechanism 18 for the high-pressure gas of the main compressor 1 is closed and the refrigerant vapor from the separator 6, which is compressed by the secondary compressor at high pressure and then passes into the condenser 3, passes via the connecting line and the multiplex valve 16 to the suction side of the secondary compressor 2.

In an alternative operating mode, the refrigerant circuit can also be operated in parallel by means of the

compressors

1, 2. In this case, both the shut-off mechanism 18 for the high-pressure gas of the primary compressor 1 is opened and the parallel line for the secondary compressor 2 is opened, so that the multi-way valve 16 in the refrigerant circuit can achieve a parallel flow of refrigerant to the suction side of the secondary compressor 2.

In fig. 2, the components in accordance with fig. 1 are again shown, with the following particularity: the gas phase from the separator 6 reaches the suction side of the secondary compressor 2 via a connecting line in which a shut-off mechanism 17 for the medium-pressure gas is implemented.

The compressors can be switched from parallel mode to series mode by the refrigerant circulation circuit shown.

Preferably, however, the compressors are connected in series. A particular advantage of both the parallel and series connection of these designs is that the liquid phase of the refrigerant is separated and the gaseous phase of the refrigerant is transported from the separator 6 directly to the respective compressor, thereby reducing the pressure losses inside the evaporator. Thereby, the distribution of the liquid and gas phases inside the evaporator can be improved when no or a small amount of the gas phase reaches the evaporator together. If the compressors are connected in series, the first expansion means 5 is responsible for the main depressurization. Additionally, the flow of the gas phase is controlled or manipulated via the shut-off means 17.

Fig. 3 shows a combination of a refrigerant circuit and a coolant circuit, wherein the refrigerant circuit in fig. 1 and 2 is augmented with a heat pump heat exchanger 10 with an associated expansion device 9. Furthermore, an additional condenser 4 is provided for thermally connecting the coolant circuit and the refrigerant circuit, which additional condenser is designed as a water condenser. The additional condenser 4 is incorporated in a coolant circulation circuit which is driven by a pump 13 of the coolant circulation circuit. The flow paths of the parallel lines of the coolant circuit are controlled by the multi-way valve 15 of the coolant circuit. A first flow path runs from the pump 13 via the multiway valve 15 to the heat pump heat exchanger 10 and then to the pump 13 via a low-temperature heat exchanger, which is also referred to as coolant-air cooler 14. The parallel lines shown run from the multi-way valve 15 of the coolant circuit to the additional condenser 4 and then to the coolant-air cooler 14.

The coolant circuit is necessary in particular for switching on the coolant circuit for the heat pump operation, and the two circuits are thermally coupled via the additional condenser 4 and the heat pump heat exchanger 10.

The design of the invention becomes particularly clear from the circuit shown in fig. 3, in which two compressor stages and thus an intermediate pressure level are formed within the refrigerant circuit. The two compressor stages are preferably realized here by means of two

separate compressors

1 and 2, wherein the particularity is that the two compressors can be operated in series connection and also in parallel connection.

The system preferably comprises the use of a water condenser 4 having at least the same or increased power as compared to a conventional air condenser. For increased power, in particular the

components

4, 8, 11 and 14 are important. These components are designed for different powers in normal operation of the installation, in cooling operation or in heat pump operation or in charging operation when the refrigerant mass flow is increased. It is particularly difficult that there is a flow rate of the refrigerant that is sufficient to enable the oil to be re-transported back to the compressor when power is low. In charging operation, the mass flow of the refrigerant and thus its flow velocity is greater, and accordingly the free flow cross section must be greater in order to be able to keep the pressure losses within a reasonable range. The heat exchanger also requires a large surface in order to be able to transmit the corresponding power. The focus here is in particular on the water condenser 4, the battery cooler 11 and the coolant-air cooler 14, wherein the heat exchanger 4 with a slightly larger heat transfer surface, on account of the high thermal conductivity of the medium located in the heat transfer section and of the material of the heat exchanger 4, meets the respective power requirements and also does not cause significant problems in terms of oil transport. Of significantly greater importance are the battery cooler 11 and the coolant-air cooler 14. In the battery cooler 11, optionally, a heat transfer line is already provided in the heat exchanger, which is shut off at a corresponding power demand by means of a switchable valve, a valve which is self-regulating by means of spring force and which opens at a corresponding pressure difference. The coolant-air heat exchanger 14 is dimensioned such that it takes care of other heat sources and is able to deliver a corresponding power output to the surroundings. In the charging operation, this power is not required and can be supplied completely to the charging process. When charging in winter, the vehicle interior space is heated.

The heat transfer area is reduced overall, since the additional surfaces are only switched on under specific operating conditions. The flow speed in the refrigerant circuit is thereby advantageously increased as a function of the parameters.

The water condenser 4 operates with a greater temperature difference in the same outer dimensions, as a result of which a higher thermal output can be transmitted for the structural volume of the heat exchanger 4.

The two

compressors

1, 2 can have an oil separator/muffler connected upstream on the suction side. Typically, an oil separator is provided on the high pressure side. For distribution reasons, the two

compressors

1, 2 should be connected to an oil separator. The silencer is designed on the high-pressure side for noise-emitting reasons.

Usually divided into two operating cycles. In cooling and heating operation, the refrigerant circuit can be operated in a single stage by means of the compressor. Naturally, the two-stage compression and the possibility of separating the refrigerant in the medium-pressure bottle for this application result in advantages both in terms of energy and also in terms of technology (more uniform distribution of the refrigerant in the battery cooler). Therefore, this is also optionally proposed. In the charging operation, both compressors are in each case operated in a two-stage or single-stage process.

Fig. 4 shows a heat pump circuit of a refrigerant circuit, which is formed in two stages in a series connection of a primary compressor 1 and a secondary compressor 2. The refrigerant is condensed in the condenser 3, depressurized in the expansion mechanism 5, and separated into a gas phase and a liquid phase in the subsequent separator 6. The gaseous phase is delivered at medium pressure to the suction side of the secondary compressor 2, while the liquid phase is simultaneously distributed to the heat pump heat exchanger 10, the battery cooler 11 and the air cooler 12, wherein the expansion means 7, 8 and 9 are respectively associated with the heat exchangers. Finally, the refrigerant evaporated in the

heat exchangers

10, 11, 12 is brought together and conducted to the suction side of the main compressor 1.

A variant of the heat pump circuit, which is not shown, consists in providing two condensers. A first condenser, i.e., a heater for an interior space of a vehicle, is installed inside an air conditioning facility of the vehicle. The second condenser is a normal air condenser, which according to a preferred embodiment can be designed as a water condenser.

The embodiment shown with three

heat exchangers

10, 11, 12 in the interior of the refrigerant system for evaporating the refrigerant can obviously be extended by a multiple evaporator device depending on the field of application. This is only a function of the position of the thermostatic expansion valves, which are each assigned a shut-off function.

As an alternative to the illustration in fig. 4, the heat pump circuit can also be designed in a single stage, with the main compressor 1 being fed directly to the condenser 3 and the gas phase being fed from the separator to the suction side of the main compressor 1. In this case, heat is conveyed from the coolant circuit via the heat pump heat exchanger 10.

In the heat pump circuit, the condenser 3 outputs heat to the interior of the motor vehicle. The advantage of the circulation circuit guide shown is that little icing occurs in the respective heat exchanger and a good storage capacity of the system is provided. Additionally, the heat of the battery cooler 11, of the air cooler 12 and of the heat pump heat exchanger 10 can be used for the heat pump. In an alternative embodiment of the heat pump circuit with a single-stage design, the expansion means 5 is operated with a fully open cross section, so that therefore compression is only carried out by means of the primary compressor 1, while the secondary compressor 2 is not operated in this operating state. The battery cooler heat is particularly advantageously used in this circuit for heating the interior of the motor vehicle.

Fig. 5 shows a modified refrigerant circuit, wherein the particularity is that the battery cooler 11 is supplied directly with liquid refrigerant from the separator 6 by means of a pump 19, and the refrigerant for evaporation is fed again at this pressure level to the separator 6, which opens into the space with the gas phase. The air cooler 12 is supplied with refrigerant at the same time as the battery cooler 11, but then conducts the evaporated refrigerant to the suction side of the main compressor 1. The expansion mechanisms 7 are respectively associated with the air coolers 12. The second compression stage is realized by the secondary compressor 2, after which the refrigerant is fed to the condenser 3. In this variant, the pressure level is low or medium, specifically for battery cooling.

One advantage is that the battery cooler 11 can also operate as a fully charged evaporator without the compressor being subjected to liquid impact. It is advantageous to maintain a precisely constant evaporation temperature level over the entire heat transfer surface.

Fig. 6 shows an alternative to the embodiment according to fig. 5, in which the battery cooler 11 is again supplied with liquid refrigerant from the separator 6 at the same time as the air cooler 12. However, the refrigerant liquid emerging from the separator is depressurized in the expansion device 8 and is adjusted to a corresponding pressure level. In a similar manner, the expansion mechanism 7 is associated with an air cooler 12. The refrigerant vapor from the battery cooler 11 is passed via the multi-way valve 20 either to the suction side of the primary compressor 1 or to the suction side of the secondary compressor 2, depending on the pressure level.

The battery cooler 11 with the expansion mechanism 8 is fed into the refrigerant circuit via the multi-way valve 20, wherein the following possibilities arise via the multi-way valve 20: the refrigerant mass flow from the battery cooler 11 is added either to the medium-pressure mass flow or to the low-pressure mass flow of the refrigerant.

The illustrated refrigerant circuit can additionally be provided with an internal heat exchanger between the low-pressure side and the high-pressure side or between the medium-pressure side and the high-pressure side. Furthermore, the irreversible expansion means can be replaced by work-producing expansion means. Both variants are used for the efficiency improvement of the circulation circuit.

List of reference numerals

1 Main compressor

2-pair compressor

3 condenser

4 additional condenser, water condenser and heat transfer device

5 medium pressure of expansion mechanism

6 separator

7 low pressure of expansion mechanism

8 low pressure of expansion mechanism

9 low pressure of expansion mechanism

10 heat pump heat transmitter, heat transmitter

11 battery cooler, electronic cooler, heat transmitter

12 air cooler, vehicle interior evaporator, heat exchanger

13 pump coolant circulation loop

14 Coolant-air cooler

15 multi-way valve coolant circulation loop

16 multi-way valve refrigerant circulation circuit and cut-off mechanism

17 medium pressure gas of stop mechanism

18 stop mechanism high-pressure gas main compressor

19 refrigerant pump

20 multiple way valve battery cooler circulation loop branch

Claims

1. Refrigerant circuit for a motor vehicle having an electric or hybrid drive, wherein a condenser (3), a first expansion mechanism (5), a separator (6) as a medium-pressure bottle and a second expansion mechanism (7) are arranged in series connection in the refrigerant flow direction, and a battery cooler (11) and an air cooler (12) are subsequently arranged in parallel connection, whereby a main compressor (1) and a secondary compressor (2) are arranged in parallel lines, wherein the high-pressure side of the main compressor (1) is connected to the suction side of the secondary compressor (2) such that the main compressor (1) and the secondary compressor (2) can be connected in series or in parallel by means of a shut-off mechanism (18) in the high-pressure line of the main compressor (1) and a multiplex valve (16) in the connection of the main compressor line and the secondary compressor line, and the separator (6) is connected on the gas side to the suction side of the secondary compressor (2), wherein an additional coolant circuit is formed, which has a pump (13), a heat pump heat exchanger (10) and a coolant air cooler (14), in which an additional condenser (4) can be connected alternatively or cumulatively via a multi-way valve (15) of the additional coolant circuit, wherein a first flow path runs from the pump (13) via the multi-way valve of the additional coolant circuit to the heat pump heat exchanger (10) and then via the coolant air cooler (14) to the pump (13), and a parallel line runs from the multi-way valve (15) of the additional coolant circuit to the additional condenser (4) and then to the coolant air cooler (14), wherein the additional condenser (4) is arranged downstream of the condenser (3) in the refrigerant circulation circuit in the refrigerant flow direction,

wherein the refrigerant vapor phase leaving the separator (6) at medium or high pressure reaches the suction side of the secondary compressor (2) via a connecting line, and

the junction of the connecting line with the suction side of the secondary compressor (2) is arranged between the secondary compressor (2) and the multi-way valve (16) in the connection of the main compressor line and the secondary compressor line.

2. The refrigerant cycle circuit as recited in claim 1,

it is characterized in that the preparation method is characterized in that,

a shut-off mechanism (17) is provided in a connection between the gas side of the separator (6) and the suction side of the secondary compressor (2).

3. The refrigerant cycle circuit as recited in claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

a second expansion mechanism (7) and a third expansion mechanism (8) are individually associated with the battery cooler (11) and the air cooler (12), respectively.

4. The refrigerant cycle circuit as recited in claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the heat pump heat exchanger (10) with the associated expansion means (9) is arranged in parallel with the battery cooler (11) and the air cooler (12) in a refrigerant circuit.

5. The refrigerant cycle circuit as recited in claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

the secondary compressor (2) is integrated into the main compressor (1) and the main compressor (1) is designed as a two-stage compressor.

6. A method for operating a refrigerant cycle circuit according to any of claims 1 to 5,

it is characterized in that the preparation method is characterized in that,

in the running operation in the air conditioning facility mode,

-compressing the refrigerant in a single stage in a main compressor (1);

-subsequently passing the refrigerant through a condenser (3) for heat dissipation;

-depressurizing the refrigerant in a first expansion means (5) to an intermediate pressure;

-evaporating the liquid phase of the refrigerant in an air cooler (12) and simultaneously in the battery cooler (11) and drawing it from the separator (6) through the main compressor (1) together with the gaseous phase.

7. The method of claim 6, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

the refrigerant is depressurized upstream of the air cooler (12) and the battery cooler (11) separately by means of a second expansion device (7) and a third expansion device (8), respectively.

8. The method according to claim 6 or 7,

it is characterized in that the preparation method is characterized in that,

the heat dissipation of the refrigerant takes place in addition to the condenser (3) in an additional condenser (4) connected downstream in series in the refrigerant circuit.

9. The method of claim 6, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

during the charging operation of the battery, the additional heat transfer surface for dissipating heat in the battery cooler (11) is cut off.

10. The method of claim 6, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

in the charging mode, the additional heat transfer surface for dissipating heat in the coolant air cooler (14) is interrupted, or the entire surface can be used by other components since it is not used.

11. The method of claim 6, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

in charging operation, the additional heat transfer surface for dissipating heat in the condenser (3) is switched off, or the constant power at the condenser is implemented at a higher pressure as a driving temperature difference.

12. A method for operating a refrigerant cycle circuit according to any of claims 1 to 5,

it is characterized in that the preparation method is characterized in that,

in the charging operation of the battery, it is,

-compressing the refrigerant in two stages in a primary compressor (1) and in a secondary compressor (2);

-drawing a gaseous phase of said refrigerant through said secondary compressor (2); and

-the liquid phase of the refrigerant is evaporated in the battery cooler (11) and sucked through the primary compressor (1).

13. The method of claim 12, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

14. The method of claim 12, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

15. The method of claim 12, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

16. The method of claim 12, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

17. A method for operating a refrigerant cycle circuit according to any of claims 1 to 5,

it is characterized in that the preparation method is characterized in that,

in the operation of a heat pump of a single stage,

-compressing the refrigerant in a single stage in a main compressor (1);

-subsequently passing the refrigerant through a condenser (3) for heat dissipation to the vehicle interior;

-drawing a gaseous phase of said refrigerant through said main compressor (1); and

-the liquid phase of the refrigerant is evaporated in the heat pump heat exchanger (10) and sucked through the primary compressor (1).

18. The method of claim 17, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

the refrigerant absorbs heat in the heat pump heat exchanger (10) additionally from a coolant circuit of the heat pump heat exchanger (10).

19. The method of claim 17, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

20. The method of claim 17, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

21. The method of claim 17, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

22. A method for operating a refrigerant cycle circuit according to any of claims 1 to 5,

it is characterized in that the preparation method is characterized in that,

in the operation of the heat pump in two stages,

-the liquid phase of the refrigerant is evaporated simultaneously in the heat pump heat exchanger (10), in the air cooler (12) and in the battery cooler (11) and sucked through the primary compressor (1).

23. The method of claim 22, wherein the first and second portions are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

24. The method of claim 22, wherein the first and second portions are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

during the charging operation of the battery, the additional heat transfer surface for dissipating heat in the battery cooler (11) is interrupted.

25. The method of claim 22, wherein the first and second portions are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

26. The method of claim 22, wherein the first and second portions are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,