System for air conditioning the air of a passenger compartment of a motor vehicle and method for operating the system

Abstract

System (1-1, 1-2) for air conditioning the air of a passenger compartment of a motor vehicle, comprising a refrigerant circuit (2-1, 2-2) with a compressor (3), a first refrigerant-air heat exchanger (4) operable as a condenser / gas cooler for heating an intake air of the passenger compartment,- a refrigerant path with a second refrigerant-to-air heat exchanger (5) that can be operated as a condenser / gas cooler or evaporator for heat transfer with ambient air with an upstream first expansion element (6) and a third refrigerant-to-air heat exchanger (7) that can be operated as an evaporator for conditioning the supply air to the passenger compartment with an upstream second expansion element (8) and - a refrigerant path with a refrigerant-to-coolant heat exchanger (9) that can be operated as an evaporator for heat transfer between a coolant for temperature control of at least one component of a motor vehicle powertrain and a refrigerant with an upstream third expansion element (10),wherein the refrigerant path with the second refrigerant-air heat exchanger (5) and the third refrigerant-air heat exchanger (7) and the refrigerant path with the refrigerant-coolant heat exchanger (9) which can be operated as an evaporator each extend from a branch point (11) to a terminal point (12) and are designed to be supplied with refrigerant independently of each other and in parallel to each other, wherein the refrigerant circuit (2-1, 2-2) has a connection point with a first connection (27a), a second connection (27b) and a third connection (27c),wherein the first connection (27a) is located between the first refrigerant-to-air heat exchanger (4) and the first expansion element (6) of the second refrigerant-to-air heat exchanger (5) and the third connection (27c) is located between the second refrigerant-to-air heat exchanger (5) and the second expansion element (8) of the third refrigerant-to-air heat exchanger (7) and a refrigerant path extends from the third connection (27c) to an outlet (26-1, 26-2) in which at least one refrigerant-to-air heat exchanger (18, 20) operable as an evaporator for conditioning the supply air of the passenger compartment with an upstream expansion element (19, 21) is located, wherein the outlet (26-1, 26-2) is located in a refrigerant flow direction upstream of the compressor (3), wherein the system (1-1, 1-2) for operation in a post-heating mode for conditioning,in particular for dehumidifying and, if necessary, cooling and reheating the supply air of the passenger compartment, is designed as follows: - to direct the refrigerant circulating in the refrigerant circuit (2-1, 2-2) and flowing out of the compressor (3) at high pressure to a refrigerant-coolant heat exchanger (28) operated as a condenser / gas cooler and to transfer heat from the refrigerant to a coolant circulating in a coolant circuit, wherein the refrigerant is at least deheated and partially liquefied or cooled when flowing through the refrigerant-coolant heat exchanger (28), wherein the heated coolant is passed through heating heat exchangers (51, 52) supplied with the supply air to heat the previously dehumidified and, if necessary, cooled supply air for a rear area of ​​the passenger compartment,- to direct the refrigerant flowing out of the refrigerant-coolant heat exchanger (28), operated as a condenser / gas cooler, to the first refrigerant-air heat exchanger (4) and to transfer heat from the refrigerant at the high-pressure level to the supply air for a front area of ​​the passenger compartment, whereby the refrigerant is completely liquefied and supercooled or cooled as it flows through the first refrigerant-air heat exchanger (4) and the previously dehumidified and, if necessary, cooled supply air is heated; - to direct the refrigerant flowing out of the first refrigerant-air heat exchanger (4) to the connection point designed as a 3 / 2-way valve (27); and - to direct the refrigerant into a partial mass flow through the second refrigerant-air heat exchanger (5), operated as an evaporator, with the upstream first expansion element (6), and a partial mass flow through the third connection (27c) of the 3 / 2-way valve (27) to the outlet (26-1,26-2) extending refrigerant path with the at least one refrigerant-to-air heat exchanger (18, 20) operated as an evaporator with the upstream expansion element (19, 21), - to expand the partial mass flow of the refrigerant directed to the second refrigerant-to-air heat exchanger (5) to a medium pressure level or a low pressure level as it flows through the first expansion element (6) and to direct the partial mass flow through the second refrigerant-to-air heat exchanger (5) operated as an evaporator, whereby the refrigerant at least partially evaporates and the heat from the ambient air is transferred to the refrigerant,and to direct the partial mass flow of refrigerant exiting the second refrigerant-air heat exchanger (5) to the third refrigerant-air heat exchanger (7) operated as an evaporator with the upstream second expansion element (8), and to expand the partial mass flow to a low-pressure level as it flows through the second expansion element (8) and to direct the partial mass flow to the third refrigerant-air heat exchanger (7) operated as an evaporator, - the partial mass flow of refrigerant directed through the refrigerant path extending from the third connection (27c) of the 3 / 2-way valve (27) to the outlet (26-1, 26-2) with the at least one refrigerant-air heat exchanger (18, 20) operated as an evaporator with the upstream expansion element (19, 21) as it flows through the expansion element (19, 21) to expand to the low-pressure level and direct the partial mass flow to the refrigerant-air heat exchanger (18, 20) operated as an evaporator,- to evaporate and, if necessary, superheat the partial mass flows of the refrigerant as they flow through the refrigerant-air heat exchangers (7, 18, 20) operated as evaporators, whereby heat is transferred from the supply air of the passenger compartment, which is guided through an air flow duct (60, 61, 62), to the refrigerant, whereby the supply air is cooled and / or dehumidified, whereby the supply air flowing through the first refrigerant-air heat exchanger (4) is heated and flows out into the front area of ​​the passenger compartment, and the supply air flowing through a heating heat exchanger (51, 52) is heated and flows out into the rear area of ​​the passenger compartment, and - to mix the partial mass flows of the refrigerant and to draw the refrigerant in through the compressor (3).

Description

[0001] The invention relates to a system for air conditioning the air in the passenger compartment of a motor vehicle. The system comprises a refrigerant circuit with a compressor, a first refrigerant-to-air heat exchanger operable as a condenser / gas cooler for heating the supply air to the passenger compartment, a refrigerant path with a second refrigerant-to-air heat exchanger operable as a condenser / gas cooler or evaporator for heat transfer with the ambient air, a third refrigerant-to-air heat exchanger operable as an evaporator for conditioning the supply air to the passenger compartment, and a refrigerant path with a refrigerant-to-coolant heat exchanger operable as an evaporator for heat transfer between a coolant for temperature control of at least one component of a motor vehicle's powertrain and the refrigerant. The invention also relates to methods for operating the system.

[0002] Motor vehicles with various drive concepts are known from the prior art. These concepts are based on drives using an internal combustion engine, an electric motor, or a combination of both engine types. Motor vehicles with a combination of internal combustion engine and electric motor drives therefore have a hybrid drive, meaning the vehicle can be driven electrically, electrically / internally, or solely by an internal combustion engine, depending on the requirements.

[0003] Electric vehicles, hybrid vehicles, fuel cell vehicles, and high-efficiency combustion engine vehicles are known to not generate enough waste heat to heat the passenger compartment to the required thermal comfort at low ambient temperatures.

[0004] A first, cost-effective, and space-saving solution for heating the supply air to the passenger compartment is an electric heater, such as a PTC heater, used to warm the incoming air, combined with a refrigerant circuit for cooling and dehumidifying the air. However, systems equipped with a PTC heater exhibit high energy consumption when the supply air temperature is low. Furthermore, the inefficient operation of an electric auxiliary heater reduces the range of battery-electric vehicles.

[0005] A second, more energy-efficient solution for heating the supply air for the passenger compartment is an air conditioning system with a heat pump function, which uses various heat sources and heat sinks, but requires a significantly larger installation space than the first solution with an electric heater. When a vehicle's air conditioning system with a heat pump function operates in cooling mode, particularly when operating a refrigerant circuit with an evaporator and a condenser / gas cooler, the heat required to evaporate the refrigerant at a low temperature and pressure level in the evaporator is absorbed from the intake air to the passenger compartment or from a coolant circuit. This coolant circuit can, for example, be used to regulate the temperature, specifically to cool, electrical components such as a traction battery in an electric vehicle. In the condenser / gas cooler, the heat absorbed by the refrigerant can be released to the environment at a higher temperature and pressure level. When the air conditioning system, or rather the refrigerant circuit of the air conditioning system with heat pump function, is operated in heating mode, the heat required to evaporate the refrigerant at the lower temperature and pressure level in the evaporator is absorbed from a heat source. Ambient air can be used as the heat source. The heat absorbed from the ambient air for evaporating the refrigerant can be transferred either directly to the refrigerant in a refrigerant-to-air heat exchanger, or first to a coolant circulating in a refrigerant circuit and then from the coolant to the refrigerant in a refrigerant-to-coolant heat exchanger.

[0006] The performance and energy efficiency of an air conditioning system with a heat pump function depend primarily on the amount of heat available at a given temperature level for evaporating the refrigerant. At low ambient temperatures, heat absorption from the ambient air is further limited by the need to prevent icing of the surface of the heat exchanger exposed to the ambient air. Icing of the heat exchanger surface reduces the heat transfer between the ambient air and the heat exchanger surface, and consequently, the heat transfer from the ambient air to the refrigerant. This reduces the amount of heat transferred from the ambient air to the refrigerant and thus the overall energy efficiency of the air conditioning system.

[0007] Furthermore, the maximum temperature difference between the temperature of the ambient air flowing into the heat exchanger and the temperature of the refrigerant is limited. This maximum temperature difference, in turn, limits the amount of heat that can be transferred from the ambient air to the refrigerant.

[0008] At very low ambient air temperatures, icing of the surface of the heat exchanger exposed to ambient air is unavoidable, meaning that the supply air for the passenger compartment cannot be adequately heated if ambient air is used as the sole heat source. To sufficiently heat the supply air for the passenger compartment at these very low ambient temperatures, the refrigerant circuit is connected on the low-pressure side to a refrigerant-coolant heat exchanger, forming a thermal link between the refrigerant circuit and a coolant circuit. This coolant circuit is designed to regulate the temperature of components of the vehicle's electric powertrain. The coolant absorbs, for example, the waste heat from at least one component of the electric powertrain, such as the battery cells of a high-voltage battery.The refrigerant-coolant heat exchanger, also known as a chiller, enables an additional transfer of heat from the coolant circulating in the refrigerant circuit, particularly a water-glycol mixture, to the refrigerant circulating in the refrigerant circuit. The heat transferred from the components of the electric drive train to the coolant can also be transferred directly to the environment, especially the ambient air, in a so-called low-temperature heat exchanger of the refrigerant circuit, without operating the refrigerant circuit.

[0009] The design of air conditioning systems with heat pump function known from the state of the art for heat distribution within battery-electrically powered vehicles is highly complex and requires a large number of components on both the refrigerant and coolant sides as well as on the air side, which causes high system costs.

[0010] Vehicles with a large passenger compartment and thus a large volume of incoming air requiring climate control, such as sports cars, commercial vehicles, SUVs, passenger vans, and minivans, require such high heating and cooling capacities that they are difficult to provide with air conditioning systems using heat pumps, which are typically used in other vehicles. This often results in a lack of sufficient comfort for passengers in the rear of the passenger compartment. Conventional, simply structured air conditioning systems, for example, allow for the straightforward integration of one or more rear air conditioning units, but are inherently energy-inefficient. With state-of-the-art, more energy-efficient air conditioning systems, particularly those using an ambient air-cooled heat exchanger, integrating one or more rear air conditioning units is not readily possible. Such more efficient air conditioning systems, however, lack a refrigerant line that continuously supplies appropriately conditioned refrigerant to the additional rear air conditioning units.

[0011] German patent DE 10 2021 131 215 A1 discloses a heat pump arrangement for battery-powered vehicles with a refrigerant circuit and coolant circuits. The refrigerant circuit comprises a compressor, a heating condenser, a first expansion valve, an ambient heat exchanger, at least one evaporator with an associated second expansion valve, a 3 / 2-way refrigerant valve with expansion function arranged parallel to the evaporator, a chiller, and a refrigerant path configured as a bypass around the chiller. A refrigerant path, configured as a bypass around the ambient heat exchanger with a third expansion valve, branches off between the heating condenser and the first expansion valve and enters the system upstream of the chiller in the direction of flow.

[0012] The object of the invention is to provide a system for air conditioning the air in a passenger compartment, particularly one with a large volume, especially for motor vehicles with a purely electric drive or a combined electric and combustion engine drive. The system should enable comfortable air conditioning of the passenger compartment with maximum energy efficiency. The system should operate reliably at both low and high ambient air temperatures. Manufacturing, maintenance, and operating costs, as well as the required installation space of the system, should be minimal.

[0013] The problem is solved by the subject matter with the features of the independent patent claims. Further developments are specified in the dependent patent claims.

[0014] The problem is solved by a system according to the invention for air conditioning the air of a passenger compartment, in particular also for heat transfer with components of an electric drive train of a motor vehicle.The system comprises a refrigerant circuit with a compressor, a first refrigerant-to-air heat exchanger operable as a condenser / gas cooler for heating the supply air to the passenger compartment, a refrigerant path with a second refrigerant-to-air heat exchanger operable as a condenser / gas cooler or evaporator for heat transfer with the ambient air with an upstream first expansion element, and a third refrigerant-to-air heat exchanger operable as an evaporator for conditioning the supply air to the passenger compartment with an upstream second expansion element, as well as a refrigerant path with a first refrigerant-to-coolant heat exchanger operable as an evaporator for heat transfer between a coolant for temperature control of at least one component of a preferably electric powertrain of the motor vehicle and the refrigerant with an upstream third expansion element. The refrigerant path with the second refrigerant-to-air heat exchanger, the third refrigerant-to-air heat exchanger, and the refrigerant path with the refrigerant-to-coolant heat exchanger (which can be operated as an evaporator) each extend from a branch point to a terminal point. The refrigerant paths can be supplied with refrigerant independently of each other and in parallel.

[0015] When the refrigerant liquefies under subcritical conditions, such as with refrigerant R134a or under certain ambient conditions with carbon dioxide, the heat exchangers are called condensers. Part of the heat transfer occurs at a constant temperature. Under supercritical conditions, or when heat is released supercritically in the heat exchanger, the refrigerant temperature decreases steadily. In this case, the heat exchanger is also referred to as a gas cooler. Supercritical operation can occur under certain ambient conditions or operating modes of the refrigerant cycle, for example, with carbon dioxide.

[0016] Components of a vehicle's electric powertrain include, for example, an electric motor, an internal charger, a transformer, or an inverter. A battery, particularly a high-voltage battery, can also be considered a component of the electric powertrain.

[0017] According to the invention, the refrigerant circuit has a connection point with a first connection, a second connection, and a third connection. The first connection is located between the first refrigerant-to-air heat exchanger and the first expansion element of the second refrigerant-to-air heat exchanger, and the third connection is located between the second refrigerant-to-air heat exchanger and the second expansion element of the third refrigerant-to-air heat exchanger. A refrigerant path extends from the third connection point to a terminal point, in which at least one refrigerant-to-air heat exchanger, operable as an evaporator, is configured for conditioning the passenger compartment's supply air and includes an upstream expansion element. The terminal point is located upstream of the compressor in the direction of refrigerant flow.

[0018] According to a further development of the invention, the refrigerant path extending from the third connection point to the outlet comprises a first flow path and a second flow path, each extending from a branch point to an outlet and capable of being supplied with refrigerant independently and in parallel to one another. The first flow path is configured with a fourth refrigerant-to-air heat exchanger, which can be operated as an evaporator and has an upstream fourth expansion element, and the second flow path is configured with a fifth refrigerant-to-air heat exchanger, which can be operated as an evaporator and has an upstream fifth expansion element.

[0019] According to a preferred embodiment of the invention, the branch point of the refrigerant paths, comprising the second refrigerant-to-air heat exchanger and the third refrigerant-to-air heat exchanger on the one hand, and the refrigerant-to-coolant heat exchanger that can be operated as an evaporator on the other, is arranged between the first refrigerant-to-air heat exchanger and the first expansion element of the second refrigerant-to-air heat exchanger. The outlet of the refrigerant paths, comprising the second refrigerant-to-air heat exchanger, the third refrigerant-to-air heat exchanger, and the refrigerant-to-coolant heat exchanger that can be operated as an evaporator, is preferably arranged upstream of the compressor in the direction of refrigerant flow.

[0020] According to an advantageous embodiment of the invention, the connection point is designed as a 3 / 2-way valve with the first port as an inlet, the second port as an outlet, and the third port as both an inlet and an outlet. The 3 / 2-way valve can be connected via the first port to an outlet of the first refrigerant-to-air heat exchanger for heating the supply air to the passenger compartment, and via the third port to an outlet of the second refrigerant-to-air heat exchanger for heat transfer to the ambient air. The 3 / 2-way valve advantageously exhibits a high degree of internal tightness.

[0021] According to a further preferred embodiment of the invention, the refrigerant circuit includes an accumulator which is arranged upstream of the compressor in the direction of refrigerant flow, so that the refrigerant flowing out of the accumulator is drawn directly into the compressor. The outlet of the refrigerant path extending from the third connection point can be located either between the third refrigerant-to-air heat exchanger and the compressor, particularly upstream of the accumulator in the direction of refrigerant flow, or between the accumulator and the compressor.

[0022] A particular advantage of the invention is that the refrigerant circuit has a connection point designed as a 3 / 2-way valve with an expansion function, comprising a first port, a second port, and a third port. In particular, the first port is configured as an inlet, and the second and third ports are each configured as outlets. The expansion function is located between the first and third ports of the 3 / 2-way valve.The 3 / 2-way valve with expansion function can be connected via the first connection to a branch point located between the second refrigerant-to-air heat exchanger for heat transfer with the ambient air and the second expansion element of the third refrigerant-to-air heat exchanger for conditioning the supply air of the passenger compartment, via the second connection to an outlet located between the third refrigerant-to-air heat exchanger and the compressor, and via the third connection to an outlet located between the third expansion element and the refrigerant-to-coolant heat exchanger that can be operated as an evaporator.

[0023] According to a further development of the invention, the system comprises an air conditioning unit with at least two airflow channels. The third refrigerant-to-air heat exchanger, which can be operated as an evaporator for conditioning the supply air to the passenger compartment, and the first refrigerant-to-air heat exchanger, which can be operated as a condenser / gas cooler for heating the supply air to the passenger compartment, are preferably arranged sequentially within a first airflow channel, which opens into the passenger compartment at a front. The fourth refrigerant-to-air heat exchanger, which can be operated as an evaporator for conditioning the supply air to the passenger compartment, is preferably arranged within a second airflow channel, which opens into the passenger compartment at a rear.The fifth refrigerant-to-air heat exchanger, which can be operated as an evaporator for conditioning the supply air to the passenger compartment, can be arranged within a third airflow duct, which enters the passenger compartment in a rear area of ​​the passenger compartment.

[0024] A particular advantage is that within the respective airflow duct, in the direction of flow of the supply air, a heating heat exchanger is provided for heating the supply air after the refrigerant-air heat exchanger which can be operated as an evaporator; this can be designed as a coolant-air heat exchanger or as an electric PTC heater.

[0025] According to a further advantageous embodiment of the invention, the refrigerant circuit comprises a refrigerant-coolant heat exchanger that can be operated as a condenser / gas cooler and a branch point designed as a 3 / 2-way valve with a first connection, a second connection, and a third connection. In particular, the first connection is designed as an inlet, and the second and third connections are each designed as an outlet.

[0026] The 3 / 2-way valve can be connected via the first connection to an outlet of the compressor, via the second connection to the refrigerant-coolant heat exchanger which can be operated as a condenser / gas cooler, and via the third connection to a discharge point located in the direction of refrigerant flow upstream of the first refrigerant-air heat exchanger.

[0027] The refrigerant-coolant heat exchanger, which can be operated as a condenser / gas cooler, is preferably arranged within a flow path extending between the second connection of the 3 / 2-way valve and the outlet point located in front of the first refrigerant-air heat exchanger.

[0028] The 3 / 2-way valves are preferably electrically actuated. The expansion elements are advantageously designed as expansion valves.

[0029] The refrigerant-to-coolant heat exchanger, which can be operated as an evaporator, and the refrigerant-to-coolant heat exchanger, which can be operated as a condenser / gas cooler, can be designed as components of a common refrigerant circuit or of separate refrigerant circuits. The refrigerant sub-circuits can also be operated together as a single refrigerant circuit or independently and with complete fluid separation, with each sub-circuit containing a closed portion of the refrigerant.

[0030] The problem is also solved by a first method according to the invention for operating the preceding system for air conditioning the air of a passenger compartment of a motor vehicle in a refrigeration system mode for conditioning, in particular for cooling and / or dehumidifying the supply air to the passenger compartment. The method comprises the following steps: - Guiding the refrigerant circulating in the refrigerant circuit and flowing out of the compressor at high pressure through the first expansion element to the second refrigerant-to-air heat exchanger, which is operated as a condenser / gas cooler, and transferring heat from the refrigerant at high pressure to ambient air, whereby the first expansion element is fully open and the refrigerant is completely liquefied and subcooled or cooled as it flows through the second refrigerant-to-air heat exchanger. - Directing the refrigerant flowing from the second refrigerant-air heat exchanger to the connection point designed as a 3 / 2-way valve and - Splitting the refrigerant into a partial mass flow through the third refrigerant-to-air heat exchanger operated as an evaporator with an upstream second expansion element and a partial mass flow through the refrigerant path extending from the third connection of the 3 / 2-way valve to the outlet point with at least one refrigerant-to-air heat exchanger operated as an evaporator with an upstream expansion element, - Expansion of the partial mass flows to a low-pressure level as they pass through the expansion devices and directing the partial mass flows to the refrigerant-air heat exchangers operated as evaporators, - Evaporation and, if necessary, superheating of the partial mass flows as they pass through the refrigerant-air heat exchangers operated as evaporators, wherein heat is transferred from the supply air of the passenger compartment, which is guided through an airflow duct, to the refrigerant, whereby the supply air is cooled and / or dehumidified, and flows out of the airflow duct into a front area of ​​the passenger compartment and a rear area of ​​the passenger compartment, respectively. - Mixing of the partial mass flows of the refrigerant in the direction of flow of the refrigerant in front of the compressor and drawing in of the refrigerant by the compressor.

[0031] According to a further development of the invention, the partial mass flow of refrigerant, which extends from the third port of the 3 / 2-way valve to the outlet, is divided into a partial mass flow through a first flow path and a partial mass flow through a second flow path. The partial mass flow through the first flow path and the partial mass flow through the second flow path are each expanded to the low-pressure level as they pass through the expansion element and evaporated and optionally superheated as they pass through the refrigerant-air heat exchanger. In each case, heat is transferred from the passenger compartment's supply air, which is routed through one of the airflow ducts, to the refrigerant, whereby the supply air is cooled and / or dehumidified and flows out of the airflow duct into the rear area of ​​the passenger compartment.The partial mass flows of the vaporous and, if necessary, superheated refrigerant are then mixed together.

[0032] According to a preferred embodiment of the invention, the refrigerant flowing out of the second refrigerant-air heat exchanger is divided into a partial mass flow to the connection point designed as a 3 / 2-way valve and a partial mass flow to the 3 / 2-way valve with expansion function. The partial mass flow directed to the 3 / 2-way valve with expansion function is expanded to the low-pressure level as it flows through the 3 / 2-way valve and is evaporated and optionally superheated as it flows through the refrigerant-coolant heat exchanger, which is operated as an evaporator. In this process, heat is transferred from a coolant circulating in a coolant circuit to the refrigerant circulating in the refrigerant circuit. The partial mass flows of the refrigerant are mixed together before being drawn in by the compressor. The cooled refrigerant is advantageously conveyed to at least one component of the drive train and thus cools the component.

[0033] The refrigerant exiting the compressor at high pressure can be routed to a refrigerant-coolant heat exchanger operating as a condenser / gas cooler. As it flows through the refrigerant-coolant heat exchanger, the refrigerant is preferably at least deheated and partially liquefied or cooled. In this process, heat is transferred from the refrigerant to the coolant circulating in a coolant circuit.

[0034] The problem is also solved by a second method according to the invention for operating the preceding system for air conditioning the air of a passenger compartment of a motor vehicle in a post-heating mode for conditioning, in particular for dehumidifying and optionally cooling and post-heating the supply air to the passenger compartment. The method comprises the following steps: - Directing the refrigerant circulating in the refrigerant circuit and flowing out of the compressor at high pressure to a refrigerant-coolant heat exchanger operated as a condenser / gas cooler, and transferring heat from the refrigerant to a coolant circulating in a coolant circuit, wherein the refrigerant is at least deheated and partially liquefied or cooled as it flows through the refrigerant-coolant heat exchanger (28), wherein the heated coolant is passed through heating heat exchangers supplied with the supply air to heat the previously dehumidified and, if necessary, cooled supply air for a rear area of ​​the passenger compartment. - Guiding the refrigerant flowing from the refrigerant-coolant heat exchanger, operated as a condenser / gas cooler, to the first refrigerant-air heat exchanger and transferring heat from the refrigerant at the high-pressure level to the supply air for a front area of ​​the passenger compartment, whereby the refrigerant is completely liquefied and supercooled or cooled as it flows through the first refrigerant-air heat exchanger and the previously dehumidified and, if necessary, cooled supply air is heated, - Directing the refrigerant flowing from the first refrigerant-air heat exchanger to the connection point designed as a 3 / 2-way valve and - Splitting the refrigerant into a partial mass flow through the second refrigerant-air heat exchanger operated as an evaporator with an upstream first expansion element and a partial mass flow through the refrigerant path extending from the third connection of the connection point designed as a 3 / 2-way valve to the outlet point with at least one refrigerant-air heat exchanger operated as an evaporator with an upstream expansion element, - Expansion of the partial mass flow of refrigerant directed to the second refrigerant-air heat exchanger as it flows through the first expansion element to a medium-pressure level or a low-pressure level, and directing the partial mass flow through the second refrigerant-air heat exchanger operated as an evaporator, whereby the refrigerant at least partially evaporates and heat is transferred from the ambient air to the refrigerant, as well as directing the partial mass flow of refrigerant flowing out of the second refrigerant-air heat exchanger operated as an evaporator to the third refrigerant-air heat exchanger operated as an evaporator with an upstream second expansion element, as well as expansion of the partial mass flow as it flows through the second expansion element to a low-pressure level, and directing the partial mass flow to the third refrigerant-air heat exchanger operated as an evaporator. - The expansion of the refrigerant path extending from the third connection of the 3 / 2-way valve to the outlet point, with the partial mass flow of refrigerant directed through at least one refrigerant-to-air heat exchanger operated as an evaporator with an upstream expansion element, as it flows through the expansion element to the low-pressure level and directs the partial mass flow to the refrigerant-to-air heat exchanger operated as an evaporator, - Evaporation and, if necessary, superheating of the partial mass flows of the refrigerant as they flow through the refrigerant-to-air heat exchangers operated as evaporators, wherein heat is transferred from the supply air of the passenger compartment, which is guided through an airflow duct, to the refrigerant, wherein the supply air is cooled and / or dehumidified, wherein the supply air flowing through the first refrigerant-to-air heat exchanger is heated and flows out into the front area of ​​the passenger compartment, and wherein the supply air flowing through a heating heat exchanger is heated and flows out into the rear area of ​​the passenger compartment, as well as - Mixing of the partial mass flows of the refrigerant and intake of the refrigerant by the compressor.

[0035] According to a further development of the invention, the partial mass flow of refrigerant, which extends from the third port of the connection point designed as a 3 / 2-way valve to the outlet, is divided into a partial mass flow through a first flow path and a partial mass flow through a second flow path. The partial mass flow flowing through the first flow path and the partial mass flow flowing through the second flow path are each expanded to the low-pressure level as they pass through the expansion element and are evaporated and, if necessary, superheated as they pass through the refrigerant-air heat exchanger.In this process, heat is transferred from the passenger compartment's supply air, which is guided through one of the airflow ducts, to the refrigerant. The supply air is cooled and / or dehumidified, then heated as it passes through the heat exchanger before flowing out of the airflow duct into the rear of the passenger compartment. The partial mass flows of the vaporous and, if applicable, superheated refrigerant are then mixed together.

[0036] According to an advantageous embodiment of the invention, the partial mass flow of refrigerant directed to the second refrigerant-air heat exchanger, which operates as an evaporator and has an upstream first expansion element, is divided into a partial mass flow to the first expansion element and a partial mass flow to the refrigerant-coolant heat exchanger, which operates as an evaporator and has an upstream third expansion element. The partial mass flow directed to the refrigerant-coolant heat exchanger, which operates as an evaporator, is expanded to the low-pressure level as it passes through the third expansion element and is evaporated and optionally superheated as it passes through the refrigerant-coolant heat exchanger. In this process, heat is transferred from the coolant circulating in a coolant circuit to the refrigerant circulating in the refrigerant circuit. The partial mass flows of refrigerant are mixed together before being drawn in by the compressor. The cooled coolant is advantageously conveyed to at least one component of the drive train, and the component is cooled.

[0037] The advantageous embodiment of the invention enables the system to be used in motor vehicles with an electric motor drive or a hybrid drive consisting of an electric motor and an internal combustion engine.

[0038] The system according to the invention can advantageously be operated in such a way that the refrigerant for dehumidifying or drying and cooling the supply air of the passenger compartment is always directed in an optimal state, in particular to expansion elements upstream of refrigerant-air heat exchangers operated as evaporators. The refrigerant is present at a high pressure level, in particular at a high-pressure or medium-pressure level, and advantageously mostly in a supercooled or at least completely or partially liquid state at the expansion elements.The refrigerant-to-air heat exchangers, which are specially arranged in an airflow duct or at least two airflow ducts, each leading into the rear area of ​​the passenger compartment, and are operated as evaporators with the upstream expansion devices, can be connected, depending on requirements and operating mode, to the outlet of the first refrigerant-to-air heat exchanger, which can be operated as a condenser / gas cooler, for heating the supply air of the passenger compartment, or to the outlet of the second refrigerant-to-air heat exchanger for heat transfer with the ambient air.

[0039] The system according to the invention with integrated heat pump functionality, in particular for purely electric or hybrid-powered motor vehicles with combustion engines, has several advantages in summary: - Meeting all requirements for the thermal management of an electric vehicle across a very wide range of ambient temperatures, including air conditioning of the passenger compartment by cooling, dehumidifying and heating, as well as temperature control, in particular cooling or heating the battery and cooling components of the powertrain, - high degree of waste heat recovery, including energy-efficient heating of the supply air for the passenger compartment by utilizing waste heat from the refrigerant circuit and recovering heat from components of the electric powertrain, thereby - Maximum energy efficiency during operation with a high degree of waste heat utilization, high flexibility and functionality, in particular high energy efficiency during operation in an ambient temperature range between 5°C and 35°C, resulting in minimal energy consumption, especially minimal consumption of electrical energy, which, for example, maximizes the range of the electric vehicle or reduces the size of the battery compared to a vehicle with a similar range. - Maximum comfort throughout the passenger compartment, even with a large air volume, such as in vehicles for more than five occupants, - Compact design with low complexity on both the refrigerant and air sides, in particular through the use of suitable refrigerant lines with appropriate flow cross-sections for a minimal overall refrigerant requirement of the system, - low costs in manufacturing and maintenance as well as during operation, especially through the use of simple, cost-effective expansion devices associated with the refrigerant-air heat exchangers.

[0040] The system, in particular the refrigerant circuit, is independent of the refrigerant used and is therefore also designed for R134a, R1234yf, R290 or other refrigerants.

[0041] Further details, features, and advantages of embodiments of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. These show: Fig. 1a: a first system for air conditioning the air of a passenger compartment of a motor vehicle with a first refrigerant circuit and Fig. 1 b: a second system for air conditioning the air of a passenger compartment of a motor vehicle with a second refrigerant circuit, Fig. 2: the first system after Fig. 1a during operation of the refrigerant circuit in a first refrigeration system mode, Fig. 3: the first system after Fig. 1a during operation of the refrigerant circuit in a second refrigeration system mode, Fig. 4: the first system after Fig. 1a during operation of the refrigerant circuit in a reheating mode as well as Fig. 5: the first system after Fig. 1a during operation of the refrigerant circuit in a first heating mode.

[0042] In the Fig. 1a and Fig. Figure 1b shows a system 1-1, 1-2 for air conditioning the air of a passenger compartment of a motor vehicle with a refrigerant circuit 2-1, 2-2.

[0043] The refrigerant circuit 2-1, 2-2, each represented by a double line, comprises, in the direction of refrigerant flow, a compressor 3 for drawing in and compressing the refrigerant, a first refrigerant-to-air heat exchanger 4 operating as a condenser / gas cooler for heating the supply air to the passenger compartment, a second refrigerant-to-air heat exchanger 5 for heat transfer with the ambient air, and a first expansion device 6, in particular an expansion valve, located upstream of the second refrigerant-to-air heat exchanger 5. The refrigerant circuit 2-1, 2-2 is also equipped with a third refrigerant-to-air heat exchanger 7 operating as an evaporator for cooling or dehumidifying the supply air to the passenger compartment, and a second expansion device 8, in particular an expansion valve, located upstream of the third refrigerant-to-air heat exchanger 7. The outlet of the third refrigerant-to-air heat exchanger 7 is connected to the compressor 3.The refrigerant circuit 2-1, 2-2 is closed. The third refrigerant-to-air heat exchanger 7, operating as an evaporator for cooling or dehumidifying the supply air to the passenger compartment, and the first refrigerant-to-air heat exchanger 4, operating as a condenser / gas cooler for heating the supply air to the passenger compartment, are arranged sequentially within a first airflow duct 60 of a vehicle air conditioning unit, in the direction of the supply air flow, in the order mentioned. The supply air guided through the first airflow duct 60 can be introduced into the passenger compartment, particularly in the front area.

[0044] The first expansion element 6, located between the first refrigerant-to-air heat exchanger 4, through which the refrigerant flows at a high pressure, and the second refrigerant-to-air heat exchanger 5, allows the refrigerant pressure level in the second refrigerant-to-air heat exchanger 5 to be adjusted to a pressure level ranging from high pressure to low pressure for heat transfer from the refrigerant to the ambient air during operation in refrigeration mode, or for heat transfer from the ambient air to the refrigerant during operation in heating mode. In this way, the system can operate at three different pressure levels, with an intermediate pressure level, also referred to as the suction pressure level of the compressor 3, that can vary between the high pressure and low pressure levels.By varying the mean pressure level of the refrigerant in the second refrigerant-air heat exchanger 5, for example, the heat transfer from the refrigerant to the ambient air can be limited or controlled when operating the system 1-1, 1-2 in refrigeration mode, and the heat absorption from the ambient air can be controlled when operating the system 1-1, 1-2 in heating mode.

[0045] The refrigerant circuit 2-1, 2-2 each has a first refrigerant-coolant heat exchanger 9, operated as an evaporator, as a thermal connection with at least one coolant circuit. The third expansion element 10 is located upstream of the first refrigerant-coolant heat exchanger 9 in the direction of refrigerant flow. The first refrigerant-coolant heat exchanger 9 and the third expansion element 10, in particular an expansion valve, are arranged within a refrigerant path that extends from a first branch point 11 to a first outlet point 12. The first branch point 11 is located between the first refrigerant-air heat exchanger 4 and the first expansion element 6 of the second refrigerant-air heat exchanger 5, while the first outlet point 12 is located between the third refrigerant-air heat exchanger 7 and the compressor 3.The first refrigerant-to-air heat exchanger 4 is thus connected to the compressor 3 via the third expansion element 10 and the first refrigerant-to-coolant heat exchanger 9, as an alternative to the flow through the second refrigerant-to-air heat exchanger 5 and the third refrigerant-to-air heat exchanger 7 (operated as an evaporator). The refrigerant path with the first refrigerant-to-coolant heat exchanger 9 and the third expansion element 10 is configured parallel to a refrigerant path with the second refrigerant-to-air heat exchanger 5 and the third refrigerant-to-air heat exchanger 7, each with its respective upstream expansion elements 6 and 8.

[0046] Furthermore, the outlet of the second refrigerant-to-air heat exchanger 5 is coupled to both the second expansion element 8 of the third refrigerant-to-air heat exchanger 7 and to a first 3 / 2-way valve 13 with expansion function. The first 3 / 2-way valve 13 has three ports 13a, 13b, and 13c. The first port 13a is configured as an inlet, and the second port 13b and the third port 13c are each configured as outlets of the first 3 / 2-way valve 13. The expansion function of the first 3 / 2-way valve 13 is provided during flow from the first port 13a to the third port 13c. The first 3 / 2-way valve 13 is connected via the first connection 13a to the second refrigerant-to-air heat exchanger 5, via the second connection 13b to the compressor 3 and via the third connection 13c to the first refrigerant-to-coolant heat exchanger 9.

[0047] The first port 13a of the first 3 / 2-way valve 13 is connected as an inlet to a second branch port 14, which is located between the second refrigerant-to-air heat exchanger 5 and the second expansion element 8 of the third refrigerant-to-air heat exchanger 7, which operates as an evaporator. The second port 13b of the first 3 / 2-way valve 13 is connected as an outlet to a second outlet port 15, which is located between the third refrigerant-to-air heat exchanger 7 and the first outlet port 12, or the compressor 3. The third connection 13c of the first 3 / 2-way valve 13 is connected as an outlet to a third opening 16, which is arranged between the third expansion element 10 of the first refrigerant-coolant heat exchanger 9 and the first refrigerant-coolant heat exchanger 9 operated as an evaporator.

[0048] While the first 3 / 2-way valve 13 can be connected via the third port 13c as an outlet with the expansion function to the first refrigerant-coolant heat exchanger 9, a direct connection to the suction side of the refrigerant circuit 2-1, 2-2 is also possible via the third port 13c as an outlet, thus creating a bypass flow path around the first refrigerant-coolant heat exchanger 9 and the third refrigerant-air heat exchanger 7 with the associated second expansion element 8. Alternatively, single valves with the corresponding functionalities can be used instead of the first 3 / 2-way valve 13 with expansion function.

[0049] The refrigerant circuit 2-1, 2-2 each also has an accumulator 17, which is connected at an outlet to a suction side of the compressor 3. The suction-side refrigerant lines from the outlet of the third refrigerant-air heat exchanger 7 (operated as evaporators) and the first refrigerant-coolant heat exchanger 9, as well as from the second connection 13b of the first 3 / 2-way valve 13, are connected to each other before an inlet of the accumulator 17 via the first outlet 12 and the second outlet 15. In this way, the refrigerant can be partially evaporated, evaporated or superheated as it flows through the second refrigerant-air heat exchanger 5, the third refrigerant-air heat exchanger 7 arranged within the first airflow channel 60 of the air conditioning unit and the first refrigerant-coolant heat exchanger 9.

[0050] The refrigerant circuit 2-1, 2-2 allows for parallel operation of the second refrigerant-to-air heat exchanger 5 and the first refrigerant-to-coolant heat exchanger 9 at different refrigerant pressure levels. If required, the second refrigerant-to-air heat exchanger 5 and the first refrigerant-to-coolant heat exchanger 9 can also be operated in series with refrigerant flow. The operating mode can be flexibly adapted to the ambient or operating conditions, such as temperatures and available heat sources in the vehicle.

[0051] The refrigerant circuit 2-1, 2-2 each also includes a fourth refrigerant-to-air heat exchanger 18 operated as an evaporator and a fifth refrigerant-to-air heat exchanger 20 operated as an evaporator, respectively, for cooling or dehumidifying the supply air of a rear area of ​​the passenger compartment, as well as a fourth expansion element 19 upstream of the fourth refrigerant-to-air heat exchanger 18 and a fifth expansion element 21 upstream of the fifth refrigerant-to-air heat exchanger 20. The fourth refrigerant-air heat exchanger 18 with the fourth expansion element 19 is arranged within a first flow path 22, and the fifth refrigerant-air heat exchanger 20 with the fifth expansion element 21 is arranged within a second flow path 23, each extending from a third branch point 24 to a fourth outlet point 25 and being able to be supplied with refrigerant in parallel.The fourth outlet 25 is connected via a refrigerant line to a fifth outlet 26-1, 26-2. The fifth outlet 26-1 of the refrigerant circuit 2-1 of system 1-1 according to . Fig. 1a is arranged between the third refrigerant-air heat exchanger 7 and the compressor 3, in particular in the direction of refrigerant flow upstream of the accumulator 17, specifically between the second outlet 15 and the first outlet 12, while the fifth outlet 26-2 of the refrigerant circuit 2-2 of the system 1-2 is located after Fig. 1b is arranged between the outlet of the accumulator 17 and the inlet of the compressor 3. The fourth expansion element 19 and the fifth expansion element 21 are, in particular, expansion valves. The expansion elements 6, 8, 10, 19, 21 can each be designed as a closable expansion valve.

[0052] The third branch point 24 is connected via a refrigerant line to a second 3 / 2-way valve 27, which serves as a connection point. The second 3 / 2-way valve 27 has three ports 27a, 27b, and 27c. The first port 27a is configured as an inlet, the second port 27b as an outlet, and the third port 27c as both an inlet and an outlet of the second 3 / 2-way valve 27. The first connection 27a of the second 3 / 2-way valve 27 is arranged as an inlet between the first refrigerant-air heat exchanger 4, operated as a condenser / gas cooler, and the first expansion element 6 of the second refrigerant-air heat exchanger 5, in particular the first branch point 11, while the second connection 27b of the second 3 / 2-way valve 27 is connected as an outlet to the third branch point 24.The third connection 27c of the second 3 / 2-way valve 27, which serves as an inlet or outlet depending on the operating mode, is arranged between the second refrigerant-to-air heat exchanger 5, in particular the second branch point 14, and the second expansion element 8 of the third refrigerant-to-air heat exchanger 7.

[0053] While the first refrigerant-to-air heat exchanger 4 can be connected to the fourth refrigerant-to-air heat exchanger 18 or the fifth refrigerant-to-air heat exchanger 20 via the first connection 27a as inlet and the second connection 27b as outlet of the second 3 / 2-way valve 27, the second refrigerant-to-air heat exchanger 5 can alternatively be connected to the fourth refrigerant-to-air heat exchanger 18 or the fifth refrigerant-to-air heat exchanger 20 via the third connection 27c as inlet and the second connection 27b as outlet of the second 3 / 2-way valve 27. Alternatively, individual shut-off valves can be used instead of the second 3 / 2-way valve 27.

[0054] Each refrigerant circuit 2-1, 2-2 also includes a second refrigerant-coolant heat exchanger 28, which operates as a condenser / gas cooler. This second heat exchanger is located upstream of the first refrigerant-air heat exchanger 4, which also operates as a condenser / gas cooler, and thus between the compressor 3 and the first refrigerant-air heat exchanger 4. In the second refrigerant-coolant heat exchanger 28, heat is transferred from the refrigerant circulating in the refrigerant circuit 2-1, 2-2 to a coolant circulating in a coolant circuit. The second refrigerant-coolant heat exchanger 28 can be configured as a thermal connection between the refrigerant circuit 2-1, 2-2 and the coolant circuit, in which the first refrigerant-coolant heat exchanger 9 is also integrated.Alternatively, the second refrigerant-coolant heat exchanger 28 can also represent a thermal connection of the refrigerant circuit 2-1, 2-2 with a second refrigerant circuit that is different from the first refrigerant circuit with the first refrigerant-coolant heat exchanger 9.

[0055] The coolant circuit or coolant circuits are used for temperature control, in particular for cooling or heating the battery or components of the electric powertrain, as well as for air conditioning the passenger compartment, in particular for heating the supply air to the passenger compartment.

[0056] Between the compressor 3 and the second refrigerant-to-coolant heat exchanger 28, a third 3 / 2-way valve 29, configured as a branch point and with three ports 29a, 29b, 29c, is arranged within the refrigerant circuit 2-1, 2-2. The first port 29a is configured as an inlet, and the second port 29b and the third port 29c are each configured as an outlet of the third 3 / 2-way valve 29. The first port 29a of the third 3 / 2-way valve 29 is connected as an inlet to the outlet of the compressor 3, while the second port 29b of the second 3 / 2-way valve 29 is connected as an outlet to the second refrigerant-to-coolant heat exchanger 28. The second refrigerant-coolant heat exchanger 28 is arranged within a flow path extending between the third 3 / 2-way valve 29 as a branch point to a sixth outlet 30.The sixth outlet 30 is formed in the direction of refrigerant flow upstream of the inlet of the first refrigerant-air heat exchanger 4. The third 3 / 2-way valve 29 is also connected to the sixth outlet 30 via the third port 29c, so that a bypass flow path around the second refrigerant-coolant heat exchanger 28 is provided between the third port 29c of the third 3 / 2-way valve 29 and the sixth outlet 30. To prevent refrigerant from flowing back to the second refrigerant-coolant heat exchanger 28 at the sixth outlet 30 when the bypass flow path is pressurized with refrigerant, a check valve 31, in particular a non-return valve, is arranged within the flow path with the second refrigerant-coolant heat exchanger 28. Alternatively, individual shut-off valves can be used instead of the third 3 / 2-way valve 29.

[0057] In addition to the respective refrigerant circuits 2-1 and 2-2, the system 1-1, 1-2 includes heating heat exchangers 50, 51, 52 for heating the supply air flowing into the passenger compartment. Each of these heat exchangers can be designed as a coolant-to-air heat exchanger and thus as a component of a coolant circuit, in particular of one coolant circuit, the first coolant circuit, or the second coolant circuit. Furthermore, an auxiliary heating heat exchanger 53, designed as an electric PTC heater, can be provided.

[0058] A first heat exchanger 50, together with the third refrigerant-to-air heat exchanger 7 (operated as an evaporator) for cooling or dehumidifying the passenger compartment's supply air, and the first refrigerant-to-air heat exchanger 4 (operated as a condenser / gas cooler) for heating the passenger compartment's supply air, are arranged within the first airflow duct 60 of the vehicle's air conditioning unit. The first heat exchanger 50 is positioned downstream of the first refrigerant-to-air heat exchanger 4 in the direction of the passenger compartment's supply air flow.

[0059] In addition to the fourth refrigerant-to-air heat exchanger 18, which operates as an evaporator and cools or dehumidifies the supply air to the rear of the passenger compartment, a second heating heat exchanger 51 is arranged within a second airflow duct 61 of the vehicle's air conditioning unit for heating the supply air to the rear of the passenger compartment. Meanwhile, next to the fifth refrigerant-to-air heat exchanger 20, which also operates as an evaporator and cools or dehumidifies the supply air to the rear of the passenger compartment, a third heating heat exchanger 52 is arranged within a third airflow duct 62 of the air conditioning unit for heating the supply air to the rear of the passenger compartment. The heating heat exchangers 51 and 52 are positioned downstream of the refrigerant-to-air heat exchangers 18 and 20, respectively, in the direction of airflow to the passenger compartment's supply air.

[0060] The auxiliary heat exchanger 53 serves to heat the coolant of the coolant circuit in which the second heating heat exchanger 51 or the third heating heat exchanger 52 are integrated, if not enough heat is transferred to the coolant in the second refrigerant-coolant heat exchanger 28.

[0061] The refrigerant circuits 2-1 and 2-2 are each equipped with various sensors, in particular pressure-temperature sensors 41 and 42 and temperature sensors 43 and 44. A first pressure-temperature sensor 41 is provided at the outlet of the compressor 3 to determine the high pressure and the outlet temperature of the refrigerant at the compressor 3. A second pressure-temperature sensor 42 is arranged downstream of the third refrigerant-to-air heat exchanger 7, which operates as an evaporator, to determine the low pressure and the outlet temperature of the refrigerant at the third refrigerant-to-air heat exchanger 7 and, consequently, the superheat of the refrigerant. A first temperature sensor 43 is provided at the outlet of the first refrigerant-air heat exchanger 4, while a second temperature sensor 44 is arranged at the outlet of the first refrigerant-coolant heat exchanger 9, which is operated as an evaporator.

[0062] The following describes various operating modes of system 1-1 with the refrigerant circuit 2-1. Fig. Figure 1a describes the following. Active components of the refrigerant circuit 2-1 are connected to each other via connecting lines, which are shown in bold. Inactive components are shown via connecting lines, which are shown in thin. The connecting lines shown in thin do not carry the refrigerant. The sections of the refrigerant circuit 2-1 through which refrigerant flows at different pressure levels are distinguished from one another by means of solid and dashed double lines. The solid double lines indicate the sections of the refrigerant circuit 2-1 through which refrigerant flows at high pressure, while the dashed double lines indicate the sections of the refrigerant circuit 2-1 through which refrigerant flows at low pressure.

[0063] When operating the first system 1-1 with the refrigerant circuit 2-1 after Fig. 1a in a first refrigeration system mode for cooling and / or dehumidifying the supply air to the passenger compartment according to Fig. In section 2, the first port 29a of the third 3 / 2-way valve 29 is connected to the second port 29b, so that the refrigerant flowing out of the compressor 3 at high pressure is directed to the second refrigerant-coolant heat exchanger 28, which operates as a condenser / gas cooler. As the refrigerant flows through the second refrigerant-coolant heat exchanger 28, it is at least partially deheated and either liquefied or cooled. The heat is transferred from the refrigerant to the coolant circulating in the coolant circuit.

[0064] The refrigerant then flows through the check valve 31 and the first refrigerant-to-air heat exchanger 4, located within the first airflow duct 60 of the air conditioner and not supplied with supply air, to the first expansion element 6 and the second refrigerant-to-air heat exchanger 5, which operates as a condenser / gas cooler. The first expansion element 6 is fully open, allowing the refrigerant to enter the second refrigerant-to-air heat exchanger 5 at high pressure. As it flows through the second refrigerant-to-air heat exchanger 5, the refrigerant is completely liquefied and supercooled. Heat is transferred from the refrigerant to the ambient air. The second refrigerant-to-air heat exchanger 28, in addition to the second refrigerant-to-air heat exchanger 5, provides further heat dissipation from the refrigerant.

[0065] The supercooled refrigerant flowing from the second refrigerant-to-air heat exchanger 5 is split at the second branch point 14 into a first partial mass flow to the first 3 / 2-way valve 13 with expansion function and a second partial mass flow to the second 3 / 2-way valve 27. As the first partial mass flow of refrigerant passes through the first 3 / 2-way valve 13, it expands to low pressure from the first inlet 13a to the outlet 13c and is then directed to the first refrigerant-to-coolant heat exchanger 9. The third expansion element 10 is closed. As the refrigerant flows through the first refrigerant-to-coolant heat exchanger 9, it evaporates and may be superheated. The heat is transferred from the coolant circulating in the coolant circuit to the refrigerant circulating in the refrigerant circuit 2-1.The coolant can be used for active cooling of the vehicle's battery.

[0066] In the area of ​​the second 3 / 2-way valve 27, a third partial mass flow of the refrigerant is diverted from the second partial mass flow directed to the second 3 / 2-way valve 27. As the second partial mass flow passes through the second expansion element 8, it expands to the low-pressure level and is then directed to the third refrigerant-to-air heat exchanger 7. The second partial mass flow of the refrigerant through the third refrigerant-to-air heat exchanger 7, which operates as an evaporator, is regulated by the second expansion element 8.

[0067] As the refrigerant flows through the third refrigerant-air heat exchanger 7, it evaporates and may be superheated. The heat is transferred from the passenger compartment's supply air, which is routed through the first airflow duct 60, to the refrigerant circulating in the refrigerant circuit 2-1. The supply air is thereby cooled and, if necessary, dehumidified, and then discharged into the front area of ​​the passenger compartment. The first and second partial mass flows of the refrigerant are mixed together at the first outlet 12 and introduced into the accumulator 17.

[0068] The third partial mass flow of the refrigerant is guided from the third port 27c, which acts as an inlet, to the second port 27b of the second 3 / 2-way valve 27, which acts as an outlet, without any pressure change. Subsequently, at the third branch point 24, a fourth partial mass flow of the supercooled refrigerant at high pressure is diverted from the third partial mass flow. The third partial mass flow of the refrigerant, flowing through the first flow path 22, expands to low pressure as it passes through the fourth expansion element 19 and is directed to the fourth refrigerant-to-air heat exchanger 18, while the fourth partial mass flow of the refrigerant, flowing through the second flow path 23, expands to low pressure as it passes through the fifth expansion element 21 and is directed to the fifth refrigerant-to-air heat exchanger 20.The third and fourth partial mass flows of the refrigerant are guided in parallel through flow paths 22 and 23. The third partial mass flow of the refrigerant through the fourth refrigerant-to-air heat exchanger 18, which operates as an evaporator, and the fourth partial mass flow of the refrigerant through the fifth refrigerant-to-air heat exchanger 20, which also operates as an evaporator, are regulated accordingly by means of the fourth expansion element 19 and the fifth expansion element 21.

[0069] As the refrigerant flows through the fourth refrigerant-to-air heat exchanger 18 and the fifth refrigerant-to-air heat exchanger 20, it is evaporated and, if necessary, superheated. The heat is transferred from the passenger compartment's supply air, which is routed through the second airflow duct 61 and the third airflow duct 62, to the refrigerant circulating in the refrigerant circuit 2-1. The supply air is cooled and, if necessary, dehumidified before being discharged into the rear of the passenger compartment. The third and fourth partial mass flows of the refrigerant are mixed at the fourth outlet 25 and routed as the third partial mass flow to the fifth outlet 26-1.At the fifth outlet 26-1, the third partial mass flow is mixed with the second partial mass flow, which is then routed as the second partial mass flow to the first outlet 12 and, mixed with the first partial mass flow, flows into the accumulator 17 at the first outlet 12. The compressor 3 draws the refrigerant from the accumulator 17.

[0070] When operating the first system 1-1 with the refrigerant circuit 2-1 after Fig. 1a in a second refrigeration system mode for cooling and / or dehumidifying the supply air to the passenger compartment after Fig. 3 is compared to operation in the first refrigeration system mode after Fig. 2. The first port 29a of the third 3 / 2-way valve 29 is connected to the third port 29c, so that the refrigerant flowing out of the compressor 3 at high pressure is directed to the first refrigerant-to-air heat exchanger 4, which is not supplied with intake air. The refrigerant passes through the first refrigerant-to-air heat exchanger 4 to the first expansion valve 6 and the second refrigerant-to-air heat exchanger 5, which operates as a condenser / gas cooler. The first expansion valve 6 is fully open, so that the refrigerant flows into the second refrigerant-to-air heat exchanger 5 at high pressure. As it flows through the second refrigerant-to-air heat exchanger 5, the refrigerant is deheated, completely liquefied, and, if necessary, supercooled or cooled. The heat is transferred from the refrigerant to the ambient air. The second refrigerant-coolant heat exchanger 28 is not supplied with refrigerant.

[0071] Otherwise, the operation of the first system 1-1 with the refrigerant circuit 2-1 in the second refrigeration system mode corresponds to the operation of the first system 1-1 with the refrigerant circuit 2-1 in the first refrigeration system mode according to Fig. 2, so that the explanations regarding Fig. 2 is referred to.

[0072] Out of Fig. 4 the first system 1-1 goes to Fig. 1a During operation of the refrigerant circuit 2-1 in a post-heating mode for dehumidifying and, if necessary, cooling and reheating the supply air to the passenger compartment, the first connection 29a of the third 3 / 2-way valve 29 is connected to the second connection 29b, so that the refrigerant flowing from the compressor 3 at high pressure is directed to the second refrigerant-coolant heat exchanger 28, which operates as a condenser / gas cooler. As the refrigerant flows through the second refrigerant-coolant heat exchanger 28, it is at least deheated and partially liquefied or cooled. The heat is transferred from the refrigerant to the coolant circulating in the coolant circuit. The heated coolant can be directed through the heating heat exchangers 51, 52 to heat the supply air for the rear area of ​​the passenger compartment.

[0073] The refrigerant then flows through the check valve 31 and the first refrigerant-to-air heat exchanger 4, which is located within the first airflow duct 60 of the air conditioning unit. As it flows through the first refrigerant-to-air heat exchanger 4, the refrigerant is completely liquefied and supercooled. The heat is transferred from the refrigerant to the supply air for the front of the passenger compartment. The supply air, which has been at least dehumidified beforehand, is thereby heated.

[0074] After exiting the first refrigerant-air heat exchanger 4, the refrigerant is split into a first partial mass flow and a second partial mass flow in the area of ​​the second 3 / 2-way valve 27. The first partial mass flow is directed to the first branch point 11. At the first branch point 11, a third partial mass flow of the refrigerant is diverted from the first partial mass flow.

[0075] The first partial mass flow is directed through the first expansion element 6 to the second refrigerant-to-air heat exchanger 5, which operates as a condenser / gas cooler. As it flows through the first expansion element 6, the first partial mass flow of refrigerant is expanded to either a medium-pressure level or the low-pressure level, depending on requirements. As it flows through the second refrigerant-to-air heat exchanger 5, the refrigerant is at least partially evaporated. Heat is transferred from the ambient air to the refrigerant. The first partial mass flow of refrigerant is then directed to the second expansion element 8. As it flows through the second expansion element 8, the first partial mass flow of refrigerant is expanded from the medium-pressure level to the low-pressure level, or, with the second expansion element 8 fully open, the first partial mass flow of refrigerant flows through the second expansion element 8 at a constant low-pressure level.The first partial mass flow of the refrigerant is then directed to the third refrigerant-air heat exchanger 7, which is operated as an evaporator. As the refrigerant flows through the third refrigerant-to-air heat exchanger 7, the first partial mass flow of refrigerant is evaporated and, if necessary, superheated. The heat is transferred from the passenger compartment's supply air, which is guided through the first airflow duct 60, to the refrigerant circulating in the refrigerant circuit 2-1. The supply air is thereby dehumidified and, if necessary, cooled, and subsequently warmed as it flows through the first refrigerant-to-air heat exchanger 4 before being discharged into the front area of ​​the passenger compartment.

[0076] The third partial mass flow of refrigerant is expanded to the low-pressure level as it flows through the third expansion element 10 and then directed to the first refrigerant-coolant heat exchanger 9. The first 3 / 2-way valve 13 is completely closed. As the refrigerant flows through the first refrigerant-coolant heat exchanger 9, it evaporates and may be superheated. The heat is transferred from the coolant circulating in the coolant circuit to the refrigerant circulating in refrigerant circuit 2-1. The coolant can be used for active cooling of the vehicle's battery or to absorb waste heat from components of the electric powertrain.

[0077] The first partial mass flow and the third partial mass flow of the refrigerant are mixed together at the first outlet 12 and introduced into the accumulator 17.

[0078] The second partial mass flow of the supercooled refrigerant at high pressure, branched off in the area of ​​the second 3 / 2-way valve 27, is guided from the first port 27a, which acts as an inlet, to the second port 27b of the second 3 / 2-way valve 27, which acts as an outlet, without a pressure change. Subsequently, a fourth partial mass flow of the refrigerant is branched off from the second partial mass flow at the third branch point 24. The second partial mass flow of the refrigerant, flowing through the first flow path 22, expands to the low-pressure level as it passes through the fourth expansion element 19 and is directed to the fourth refrigerant-to-air heat exchanger 18, while the fourth partial mass flow of the refrigerant, flowing through the second flow path 23, expands to the low-pressure level as it passes through the fifth expansion element 21 and is directed to the fifth refrigerant-to-air heat exchanger 20.The second and fourth partial mass flows of the refrigerant are guided in parallel through flow paths 22 and 23. The second partial mass flow of the refrigerant through the fourth refrigerant-to-air heat exchanger 18, which operates as an evaporator, and the fourth partial mass flow of the refrigerant through the fifth refrigerant-to-air heat exchanger 20, which also operates as an evaporator, are regulated accordingly by means of the fourth expansion element 19 and the fifth expansion element 21. As the refrigerant flows through the fourth refrigerant-to-air heat exchanger 18 and the fifth refrigerant-to-air heat exchanger 20, it is evaporated and, if necessary, superheated. The heat is transferred from the passenger compartment supply air, which is directed through the second airflow duct 61 and the third airflow duct 62, to the refrigerant circulating in the refrigerant circuit 2-1. The supply air is dehumidified and, if necessary, cooled, and as it flows through the second heating heat exchanger 51 and the third heating heat exchanger 52, respectively, it is heated and then discharged into the rear of the passenger compartment. The second and fourth partial mass flows of the refrigerant are mixed at the fourth outlet 25 and directed as the second partial mass flow to the fifth outlet 26-1.At the fifth outlet 26-1, the first partial mass flow is mixed with the second partial mass flow, which is then routed as the first partial mass flow to the first outlet 12 and, at the first outlet 12, mixed with the third partial mass flow, enters the accumulator 17. The compressor 3 draws the refrigerant from the accumulator 17.

[0079] In Fig. 5 is the first system 1-1 after Fig.Figure 1a shows the operation of the refrigerant circuit 2-1 in a heating mode. The first port 29a of the third 3 / 2-way valve 29 is connected to the second port 29b, so that the refrigerant flowing from the compressor 3 at high pressure is directed to the second refrigerant-coolant heat exchanger 28, which operates as a condenser / gas cooler. As the refrigerant flows through the second refrigerant-coolant heat exchanger 28, it is at least partially deheated and partially liquefied or cooled. The heat is transferred from the refrigerant to the coolant circulating in the coolant circuit. The heated coolant can then be directed through the heating heat exchangers 51 and 52 to heat the supply air for the rear of the passenger compartment.

[0080] The refrigerant then flows through the check valve 31 and the first refrigerant-to-air heat exchanger 4, which is located within the first airflow duct 60 of the air conditioning unit. As it flows through the first refrigerant-to-air heat exchanger 4, the refrigerant is completely liquefied and, if necessary, supercooled or cooled. The heat is transferred from the refrigerant to the supply air for the front of the passenger compartment, which is thereby warmed.

[0081] After exiting the first refrigerant-air heat exchanger 4, the refrigerant is directed to the first branch point 11. At the first branch point 11, the refrigerant mass flow is split into a first partial mass flow and a second partial mass flow.

[0082] The first partial mass flow is directed through the first expansion element 6 to the second refrigerant-to-air heat exchanger 5, which operates as a condenser / gas cooler. As it flows through the first expansion element 6, the first partial mass flow of refrigerant is expanded to the low-pressure level. Upon flowing through the second refrigerant-to-air heat exchanger 5, the refrigerant evaporates and, if necessary, superheats. Heat is transferred from the ambient air to the refrigerant. Subsequently, the first partial mass flow of refrigerant, without pressure change, passes through the second branch 14 and from the first port 13a to the second port 13b via the first 3 / 2-way valve 13.

[0083] The second partial mass flow of the refrigerant is expanded to the low-pressure level as it flows through the third expansion element 10 and is then directed to the first refrigerant-coolant heat exchanger 9. As it flows through the first refrigerant-coolant heat exchanger 9, the refrigerant evaporates and may be superheated. The heat is transferred from the coolant circulating in the coolant circuit to the refrigerant circulating in refrigerant circuit 2-1. The coolant can be used for active cooling of the vehicle's battery or to absorb waste heat from components of the electric powertrain.

[0084] The first partial mass flow and the second partial mass flow of the refrigerant are mixed together at the first outlet 12 and introduced into the accumulator 17.

[0085] The second 3 / 2-way valve 27 is not supplied with refrigerant. The second expansion element 8, the fourth expansion element 19, and the fifth expansion element 21 are closed. The third refrigerant-to-air heat exchanger 7, the fourth refrigerant-to-air heat exchanger 18, and the fifth refrigerant-to-air heat exchanger 20, which can be operated as evaporators, are not supplied with refrigerant. Liquid refrigerant can be stored, for example, in the refrigerant lines extending from the closed second 3 / 2-way valve 27, in particular from the second connection 27b of the second 3 / 2-way valve 27, to the third branch point 24, and in the refrigerant lines extending from the third branch point 24 to the fourth expansion element 19 and the fifth expansion element 21, in order to make the heat pump operation more energy-efficient. The refrigerant lines serve as intermediate refrigerant storage.This allows the service life of the compressor 3 to be maximized and the internal volume of the accumulator 17 to be minimized. LIST OF REFERENCE MARKS 1-1, 1-2 system 2-1, 2-2 refrigerant circuit 3 compressors 4 first refrigerant-to-air heat exchanger 5 second refrigerant-to-air heat exchanger 6 first expansion organ 7 third refrigerant-to-air heat exchanger 8 second expansion organ 9 first refrigerant-to-refrigerant heat exchanger 10 third expansion organ 11 first junction 12 first mouth 13 first 3 / 2-way valve 13a first connection first 3 / 2-way valve 13 13b second connection first 3 / 2-way valve 13 13c third connection first 3 / 2-way valve 13 14 second junction 15 second mouth 16 third estuary 17 Accumulator 18 fourth refrigerant-to-air heat exchanger 19 fourth expansion organ 20 fifth refrigerant-to-air heat exchanger 21 fifth expansion organ 22 first flow path 23 second flow path 24 third junction 25 fourth estuary 26-1, 26-2 fifth mouth 27 second 3 / 2-way valve 27a first connection second 3 / 2-way valve 27 27b second connection second 3 / 2-way valve 27 27c third connection second 3 / 2-way valve 27 28 second refrigerant-to-refrigerant heat exchanger 29 third 3 / 2-way valve 29a first connection third 3 / 2-way valve 29 29b second connection third 3 / 2-way valve 29 29c third connection third 3 / 2-way valve 29 30 sixth estuary 31 Check valve 41 first pressure-temperature sensor 42 second pressure-temperature sensor 43 first temperature sensor 44 second temperature sensor 50 first heat exchanger 51 second heat exchanger 52 third heat exchanger 53 Auxiliary heat exchangers 60 first airflow channel 61 second airflow channel 62 third airflow channel QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102021131215 A1

[0011]

Claims

[1] System (1-1, 1-2) for air conditioning the air of a passenger compartment of a motor vehicle, comprising a refrigerant circuit (2-1, 2-2) with - a compressor (3), - a first refrigerant-air heat exchanger (4) operable as a condenser / gas cooler for heating the supply air of the passenger compartment, - a refrigerant path with a second refrigerant-air heat exchanger (5) operable as a condenser / gas cooler or evaporator for heat transfer with the ambient air with an upstream first expansion element (6) and a third refrigerant-air heat exchanger (7) operable as an evaporator for conditioning the supply air of the passenger compartment with an upstream second expansion element (8) and - a refrigerant path with a refrigerant-to-coolant heat exchanger (9) operable as an evaporator for heat transfer between a coolant for tempering at least one component of a drive train of the motor vehicle and the refrigerant with an upstream third expansion element (10), wherein the refrigerant path with the second refrigerant-to-air heat exchanger (5) and the third refrigerant-to-air heat exchanger (7) and the refrigerant path with the refrigerant-to-coolant heat exchanger (9) operable as an evaporator each extend from a branch point (11) to a mouth point (12) and are designed to be supplied with refrigerant independently of one another and parallel to one another, characterized bythat the refrigerant circuit (2-1, 2-2) has a connection point with a first connection (27a), a second connection (27b) and a third connection (27c), wherein the first connection (27a) is arranged between the first refrigerant-air heat exchanger (4) and the first expansion element (6) of the second refrigerant-air heat exchanger (5) and the third connection (27c) is arranged between the second refrigerant-air heat exchanger (5) and the second expansion element (8) of the third refrigerant-air heat exchanger (7), and a refrigerant path extends from the third connection (27c) to an outlet point (26-1, 26-2), in which at least one refrigerant-air heat exchanger (18, 20) operable as an evaporator for conditioning the supply air of the passenger compartment with an upstream expansion element (19, 21), wherein the outlet point (26-1, 26-2) is arranged in front of the compressor (3) in the flow direction of the refrigerant. [2] System (1-1, 1-2) according to claim 1, characterized by in that the refrigerant path extending from the third connection (27c) of the connection point to the mouth point (26-1, 26-2) has a first flow path (22) and a second flow path (23), which each extend from a branch point (14) to a mouth point (25) and are designed to be supplied with refrigerant independently of one another and parallel to one another, wherein the first flow path (22) has a fourth refrigerant-air heat exchanger (18) which can be operated as an evaporator and has a fourth expansion element (19) upstream, and the second flow path (23) has a fifth refrigerant-air heat exchanger (20) which can be operated as an evaporator and has a fifth expansion element (21) upstream. [3] System (1-1, 1-2) according to claim 1 or 2, characterized bythat the branching point (11) of the refrigerant paths with the second refrigerant-air heat exchanger (5) and the third refrigerant-air heat exchanger (7) and the refrigerant-coolant heat exchanger (9) operable as an evaporator is arranged between the first refrigerant-air heat exchanger (4) and the first expansion element (6) of the second refrigerant-air heat exchanger (5). [4] System (1-1, 1-2) according to one of claims 1 to 3, characterized by that the outlet point (12) of the refrigerant paths with the second refrigerant-air heat exchanger (5) and the third refrigerant-air heat exchanger (7) and the refrigerant-coolant heat exchanger (9) operable as an evaporator are arranged upstream of the compressor (3) in the flow direction of the refrigerant. [5] System (1-1, 1-2) according to one of claims 1 to 4, characterized bythat the connection point is designed as a 3 / 2-way valve (27) with the first connection (27a) as an inlet, the second connection (27b) as an outlet and the third connection (27c) as an inlet and an outlet. [6] System (1-1, 1-2) according to one of claims 1 to 5, characterized by that the refrigerant circuit (2-1, 2-2) has an accumulator (17) which is arranged in front of the compressor (3) in the flow direction of the refrigerant. [7] System (1-1) according to claim 6, characterized by that the outlet point (26-1) of the refrigerant path extending from the third connection (27c) of the connection point is arranged between the third refrigerant-air heat exchanger (7) and the compressor (3), in particular in the flow direction of the refrigerant upstream of the accumulator (17). [8] System (1-2) according to claim 6, characterized bythat the outlet point (26-2) of the refrigerant path extending from the third connection (27c) of the connection point is arranged between the accumulator (17) and the compressor (3). [9] System (1-1, 1-2) according to one of claims 1 to 8, characterized by in that the refrigerant circuit (2-1, 2-2) has a connection point designed as a 3 / 2-way valve (13) with expansion function with a first connection (13a), a second connection (13b) and a third connection (13c), wherein the first connection (13a) is designed as an inlet and the second connection (13b) and the third connection (13c) are each designed as an outlet and the expansion function is between the first connection (13a) and the third connection (13c). [10] System (1-1, 1-2) according to claim 9, characterized byin that the first connection (13a) of the 3 / 2-way valve (13) is connected to a branch point (14) arranged between the second refrigerant-air heat exchanger (5) and the second expansion element (8) of the third refrigerant-air heat exchanger (7), the second connection (13b) of the 3 / 2-way valve (13) is connected to an outlet point (15) arranged between the third refrigerant-air heat exchanger (7) and the compressor (3), and the third connection (13c) of the 3 / 2-way valve (13) is connected to an outlet point (16) arranged between the third expansion element (10) and the refrigerant-coolant heat exchanger (9) which can be operated as an evaporator. [11] System (1-1, 1-2) according to one of claims 2 to 10, characterized by that an air conditioning device is designed with at least two air flow channels (60, 61, 62), wherein - the third refrigerant-air heat exchanger (7) operable as an evaporator for conditioning the supply air of the passenger compartment and the first refrigerant-air heat exchanger (4) operable as a condenser / gas cooler for heating the supply air of the passenger compartment are arranged one after the other in the flow direction of the supply air within a first air flow duct (60) which opens into the passenger compartment in a front region of the passenger compartment, and - the fourth refrigerant-air heat exchanger (18) operable as an evaporator for conditioning the supply air of the passenger compartment is arranged within a second air flow duct (61) which opens into the passenger compartment in a rear region of the passenger compartment. [12] System (1-1, 1-2) according to claim 11, characterized bythat the fifth refrigerant-air heat exchanger (20) which can be operated as an evaporator for conditioning the supply air of the passenger compartment is arranged within a third air flow duct (62) which opens into the passenger compartment in a rear region of the passenger compartment. [13] System (1-1, 1-2) according to one of claims 11 or 12, characterized by that within the respective air flow channel (60, 61, 62) in the flow direction of the supply air, after the refrigerant-air heat exchanger (7, 18, 20), a heating heat exchanger (50, 51, 52) for heating the supply air is arranged, which is designed as a coolant-air heat exchanger or as an electric PTC heater. [14] System (1-1, 1-2) according to one of claims 1 to 13, characterized byin that the refrigerant circuit (2-1, 2-2) has a refrigerant-coolant heat exchanger (28) which can be operated as a condenser / gas cooler and a branch point designed as a 3 / 2-way valve (29) with a first connection (29a), a second connection (29b) and a third connection (29c), wherein the first connection (29a) is designed as an inlet and the second connection (29b) and the third connection (29c) are each designed as an outlet. [15] System (1-1, 1-2) according to claim 14, characterized by that the first connection (29a) of the 3 / 2-way valve (29) is connected to an outlet of the compressor (3), the second connection (29b) of the 3 / 2-way valve (29) is connected to the refrigerant-coolant heat exchanger (28) which can be operated as a condenser / gas cooler, and the third connection (29c) of the 3 / 2-way valve (29) is connected to an outlet point (30) arranged upstream of the first refrigerant-air heat exchanger (4) in the flow direction of the refrigerant. [16] System (1-1, 1-2) according to claim 14 or 15, characterized by that the refrigerant-coolant heat exchanger (28) which can be operated as a condenser / gas cooler is arranged within a flow path extending between the second connection (29b) of the 3 / 2-way valve (29) up to the mouth point (30) arranged in front of the first refrigerant-air heat exchanger (4). [17] Method for operating the system (1-1, 1-2) for air conditioning the air of a passenger compartment of a motor vehicle according to one of claims 1 to 16 in a refrigeration system mode for conditioning, in particular for cooling and / or dehumidifying the supply air of the passenger compartment, comprising the following steps: - guiding the refrigerant circulating in the refrigerant circuit (2-1, 2-2) and flowing out of the compressor (3) at high pressure level through the first expansion element (6) to the second refrigerant-air heat exchanger (5) operated as a condenser / gas cooler and transferring heat from the refrigerant at the high pressure level to ambient air, wherein the first expansion element (6) is fully opened and the refrigerant is fully liquefied and subcooled or cooled as it flows through the second refrigerant-air heat exchanger (5), - guiding the refrigerant flowing out of the second refrigerant-air heat exchanger (5) to the connection point designed as a 3 / 2-way valve (27) and - dividing the refrigerant into a partial mass flow through the third refrigerant-air heat exchanger (7) operated as an evaporator with an upstream second expansion element (8) and a partial mass flow through the refrigerant path extending from the third connection (27c) of the 3 / 2-way valve (27) to the orifice point (26-1, 26-2) with the at least one refrigerant-air heat exchanger (18, 20) operated as an evaporator with an upstream expansion element (19, 21), - Relaxing the partial mass flows as they flow through the expansion elements (8, 19, 21) to a low pressure level and directing the partial mass flows to the refrigerant-air heat exchangers (7, 18, 20) operated as evaporators, - evaporation and, if necessary, superheating of the partial mass flows as they flow through the refrigerant-air heat exchangers (7, 18, 20) operated as evaporators, wherein heat is transferred from the supply air of the passenger compartment guided through an air flow duct (60, 61, 62) to the refrigerant, wherein the supply air is cooled and / or dehumidified and flows out of the air flow duct (60, 61, 62) into a front area of ​​the passenger compartment and a rear area of ​​the passenger compartment, and - Mixing of the partial mass flows of the refrigerant in the flow direction of the refrigerant upstream of the compressor (3) and suction of the refrigerant by the compressor (3). [18] Method according to claim 17, characterized bythat the partial mass flow of the refrigerant conducted through the refrigerant path extending from the third connection (27c) of the 3 / 2-way valve (27) to the orifice point (26-1, 26-2) is divided into a partial mass flow through a first flow path (22) and a partial mass flow through a second flow path (23), wherein the partial mass flow flowing through the first flow path (22) and the partial mass flow flowing through the second flow path (23) are each expanded to the low-pressure level when flowing through the expansion element (19, 21) and evaporated and optionally superheated when flowing through the refrigerant-air heat exchanger (18, 20), wherein heat is transferred from the supply air of the passenger compartment conducted through one of the air flow channels (61, 62) to the refrigerant, wherein the supply air is respectively cooled and / or dehumidified and flows out of the air flow duct (61, 62) into the rear area of ​​the passenger compartment,and wherein the partial mass flows of the vaporous and optionally superheated refrigerant are mixed with each other., [19] Method according to claim 17 or 18, characterized byin that the refrigerant flowing out of the second refrigerant-air heat exchanger (5) is divided into a partial mass flow to the connection point designed as a 3 / 2-way valve (27) and a partial mass flow to a 3 / 2-way valve (13) with an expansion function, wherein the partial mass flow directed to the 3 / 2-way valve (13) with an expansion function is expanded to the low pressure level when flowing through the 3 / 2-way valve (13) and is evaporated and optionally superheated when flowing through the refrigerant-coolant heat exchanger (9) operated as an evaporator, wherein heat is transferred from a coolant circulating in a coolant circuit to the refrigerant circulating in the refrigerant circuit (2-1, 2-2), and the partial mass flows of the refrigerant are mixed with one another before being sucked in by the compressor (3). [20] Method according to one of claims 17 to 19, characterized bythat the refrigerant flowing out of the compressor (3) at high pressure level is conducted to a refrigerant-coolant heat exchanger (28) operated as a condenser / gas cooler, wherein the refrigerant is at least deheated and partially liquefied or cooled as it flows through the refrigerant-coolant heat exchanger (28) and the heat is transferred from the refrigerant to the coolant circulating in a coolant circuit. [21] Method for operating the system (1-1, 1-2) for air conditioning the air of a passenger compartment of a motor vehicle according to one of claims 1 to 16 in a reheating mode for conditioning, in particular for dehumidifying and optionally cooling and reheating the supply air of the passenger compartment, comprising the following steps: - guiding the refrigerant circulating in the refrigerant circuit (2-1, 2-2) and flowing out of the compressor (3) at high pressure to a refrigerant-coolant heat exchanger (28) operated as a condenser / gas cooler, and transferring heat from the refrigerant to a coolant circulating in a coolant circuit, wherein the refrigerant is at least deheated and partially liquefied or cooled as it flows through the refrigerant-coolant heat exchanger (28), wherein the heated coolant is passed through heating heat exchangers (51, 52) supplied with the supply air to heat the previously dehumidified and optionally cooled supply air for a rear region of the passenger compartment, - guiding the refrigerant flowing out of the refrigerant-to-coolant heat exchanger (28) operated as a condenser / gas cooler to the first refrigerant-to-air heat exchanger (4) and transferring heat from the refrigerant at the high-pressure level to the supply air for a front area of ​​the passenger compartment, wherein the refrigerant is completely liquefied and subcooled or cooled as it flows through the first refrigerant-to-air heat exchanger (4) and the previously dehumidified and optionally cooled supply air is heated, - guiding the refrigerant flowing out of the first refrigerant-air heat exchanger (4) to the connection point designed as a 3 / 2-way valve (27) and - dividing the refrigerant into a partial mass flow through the second refrigerant-air heat exchanger (5) operated as an evaporator with an upstream first expansion element (6) and a partial mass flow through the refrigerant path extending from the third connection (27c) of the 3 / 2-way valve (27) to the orifice point (26-1, 26-2) with the at least one refrigerant-air heat exchanger (18, 20) operated as an evaporator with an upstream expansion element (19, 21), - expanding the partial mass flow of the refrigerant directed to the second refrigerant-to-air heat exchanger (5) as it flows through the first expansion element (6) to a medium-pressure level or a low-pressure level and directing the partial mass flow through the second refrigerant-to-air heat exchanger (5) operated as an evaporator, whereby the refrigerant is at least partially evaporated and the heat from the ambient air is transferred to the refrigerant, as well as directing the partial mass flow of the refrigerant flowing out of the second refrigerant-to-air heat exchanger (5) to the third refrigerant-to-air heat exchanger (7) operated as an evaporator with an upstream second expansion element (8), as well as expanding the partial mass flow as it flows through the second expansion element (8) to a low-pressure level and directing the partial mass flow to the third refrigerant-to-air heat exchanger (7) operated as an evaporator, - expanding the partial mass flow of the refrigerant, which is guided through the refrigerant path extending from the third connection (27c) of the 3 / 2-way valve (27) to the orifice point (26-1, 26-2), with the at least one refrigerant-air heat exchanger (18, 20) operated as an evaporator with an upstream expansion element (19, 21), to the low-pressure level as it flows through the expansion element (19, 21) and directing the partial mass flow to the refrigerant-air heat exchanger (18, 20) operated as an evaporator, - evaporation and, if necessary, superheating of the partial mass flows of the refrigerant as they flow through the refrigerant-air heat exchangers (7, 18, 20) operated as evaporators, wherein heat is transferred from the supply air of the passenger compartment guided through an air flow duct (60, 61, 62) to the refrigerant, wherein the supply air is cooled and / or dehumidified, wherein the supply air flowing through the first refrigerant-air heat exchanger (4) is heated and flows out into the front area of ​​the passenger compartment and the supply air flowing through a heating heat exchanger (51, 52) is heated and flows out into the rear area of ​​the passenger compartment, and - Mixing of the partial mass flows of the refrigerant and suction of the refrigerant by the compressor (3). [22] Method according to claim 21, characterized bythat the partial mass flow of the refrigerant conducted through the refrigerant path extending from the third connection (27c) of the 3 / 2-way valve (27) to the orifice point (26-1, 26-2) is divided into a partial mass flow through a first flow path (22) and a partial mass flow through a second flow path (23), wherein the partial mass flow flowing through the first flow path (22) and the partial mass flow flowing through the second flow path (23) are each expanded to the low-pressure level when flowing through the expansion element (19, 21) and evaporated and optionally superheated when flowing through the refrigerant-air heat exchanger (18, 20), wherein heat is transferred from the supply air of the passenger compartment conducted through one of the air flow channels (61, 62) to the refrigerant, wherein the supply air is respectively cooled and / or dehumidified, is heated when flowing through the heat exchanger (51, 52) and from the air flow channel (61,62) flows into the rear area of ​​the passenger compartment, and the partial mass flows of the vaporous and possibly superheated refrigerant are mixed together. [23] Method according to claim 21 or 22, characterized bythat the partial mass flow of the refrigerant directed to the second refrigerant-air heat exchanger (5) operated as an evaporator with an upstream first expansion element (6) is divided into a partial mass flow to the first expansion element (6) and a partial mass flow to the refrigerant-coolant heat exchanger (9) operated as an evaporator with an upstream third expansion element (10), wherein the partial mass flow directed to the refrigerant-coolant heat exchanger (9) operated as an evaporator is expanded to the low pressure level when flowing through the third expansion element (10) and is evaporated and optionally superheated when flowing through the refrigerant-coolant heat exchanger (9), wherein heat is transferred from the coolant circulating in a coolant circuit to the refrigerant circulating in the refrigerant circuit (2-1, 2-2), and the partial mass flows of the refrigerant before being sucked in by the Compressor (3) are mixed together.

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