CN111692778B

CN111692778B - Method for operating a refrigeration system of a vehicle having a refrigerant circuit with a heat pump function

Info

Publication number: CN111692778B
Application number: CN202010164867.6A
Authority: CN
Inventors: D·施罗德; C·雷宾格尔; H·罗腾科尔布
Original assignee: Audi AG
Current assignee: Audi AG
Priority date: 2019-03-12
Filing date: 2020-03-11
Publication date: 2022-11-11
Anticipated expiration: 2040-03-11
Also published as: DE102019203292A1; CN111692778A; DE102019203292B4

Abstract

The invention relates to a method for operating a refrigeration device (10) of a vehicle having a refrigerant circuit (1) having a heat pump function, said refrigerant circuit having a refrigerant compressor (4); an external heat exchanger (5) which can be operated as a condenser or gas cooler or as a heat pump evaporator and which has an associated heat pump expansion element (AE 3); a heating condenser (8) or a hot gas radiator (8); an evaporator (2) and an associated evaporator expansion device (AE 2), wherein the refrigerant compressor (4) is connected to a heating condenser (8) or a hot-gas radiator (8) for carrying out a heating operation, and a refrigerant outlet (KA) of the heating condenser (8) or the hot-gas radiator (8) is connected directly and/or indirectly to an inlet side of the refrigerant compressor (4) by means of a heating expansion device (AE 1, AE3, AE4, AE 5), wherein the heating expansion device expands the refrigerant to a low pressure.

Description

Method for operating a refrigeration device of a vehicle having a refrigerant circuit with a heat pump function

Technical Field

The invention relates to a method for operating a refrigeration system of a vehicle, which refrigeration system has a refrigerant circuit with a heat pump function.

Background

Refrigeration devices are known which can be used both for heating the vehicle interior during the heat pump process and for cooling the vehicle interior during operation of the refrigeration device. In the heat pump process, the supply air supplied to the vehicle interior is heated by the heat pump.

For example, a refrigeration device for a vehicle is known from DE 10 2012 100 A1, which comprises a refrigerant circuit having a heat pump function. In order to implement the heat pump function, a heat pump condenser, which is an internal condenser or a heating condenser, a refrigerating unit, and a heat pump evaporator are connected in series, as well as a refrigerator with a corresponding expansion device, which serves as an additional heat pump evaporator. In terms of coolant, the refrigerator is designed in a cooling water circuit for cooling the drive motor, the electronic power unit and/or the battery. In addition, a PTC heating element is provided for the cooling water circuit for heating the cooling water. The evaporator in the air conditioner of this embodiment functions as an evaporator in the operation of the refrigeration apparatus and functions as a condenser or a gas radiator in the heat pump process, and thus serves to both cool and heat the supply air flow flowing into the vehicle compartment.

Disclosure of Invention

The object of the invention is to provide a method for operating a vehicle refrigeration system having a refrigerant circuit with a heat pump function, by means of which heating operation can be carried out efficiently and with little structural expenditure. This heating operation (also referred to as a delta process) is performed only in the refrigerant compressor, the expansion mechanism, and the heat exchanger that can be used for the heating operation.

This object is achieved by a method having the features of claim 1.

In a method for operating a refrigeration system of a vehicle having a refrigerant circuit with a heat pump function, the refrigerant circuit has the following components:

-a refrigerant compressor having a high pressure outlet and an inlet side,

an AC-and heat pump branch with an external heat exchanger which can be operated either as a condenser or as a gas cooler or as a heat pump evaporator and a heat pump expansion means which can be used for the heat pump function, wherein the AC-and heat pump branch can be connected to the high-pressure outlet of the refrigerant compressor,

a heating branch with a heating condenser or a hot gas radiator, wherein the heating condenser or the hot gas radiator can directly or indirectly heat a supply air stream for the vehicle interior, wherein, for carrying out the heat pump process, the heating branch is connectable upstream to the high-pressure outlet of the refrigerant compressor and downstream to the AC-and heat pump branches,

-an evaporator branch having an evaporator and an evaporator expansion mechanism, wherein the evaporator branch is connectable on a low pressure side to an inlet side of a refrigerant compressor and on a high pressure side to an AC-and heat pump branch, and

a heat pump return branch with a blocking mechanism connectable upstream to an external heat exchanger and downstream to an inlet side of a refrigerant compressor,

wherein, in order to implement heating operation

-the high pressure outlet of the refrigerant compressor is connected to the heating branch, an

The refrigerant outlet of the heating condenser or the hot gas radiator is directly and/or indirectly connected to the heat pump return branch and/or indirectly to the inlet side of the refrigerant compressor by means of a heating-expansion mechanism which expands the refrigerant to a low pressure.

In this method according to the invention, the existing components of the refrigerant circuit are connected accordingly to carry out the heating operation.

According to an advantageous development of the invention, for carrying out the heating operation, the refrigerant outlet of the heating condenser or of the hot-gas radiator is directly connected to the heat pump return branch by means of a heating branch comprising a heating-expansion mechanism, wherein the refrigerant is expanded to a low pressure by means of the heating-expansion mechanism. The advantage here is that the heating function is performed solely with the driving power of the compressor, irrespective of the ambient temperature and/or the coolant temperature level, that is to say without an external heat source.

In addition, an advantageous embodiment of the invention provides that, for carrying out the heating operation, the refrigerant outlet of the heating condenser or of the hot-gas radiator is connected directly to the heat pump return branch by means of a reheat branch having a reheat expansion mechanism, wherein the refrigerant is expanded to a low pressure by means of the reheat expansion mechanism as a heating expansion mechanism. The advantage here is that already existing components and system parts for other functions can be used in this case for heating the supply air flow of the vehicle interior, without expensive and complicated modifications in the design of the refrigerating device being necessary.

According to a further advantageous development of the invention, the refrigerant outlet of the heating condenser or of the hot-gas radiator is connected to a refrigerant branch having a refrigerator and a refrigerator expansion device for carrying out the heating operation, wherein the refrigerant is expanded to a low pressure using the refrigerator expansion device as an auxiliary expansion device. The advantage here is that in this case, again, already existing components and system parts for other functions can be used for heating the supply air flow of the vehicle interior, without expensive and complicated modifications in the design of the refrigerating device being necessary. In addition to serving as a heat source for the water heat pump process, the chiller branch may also serve as a bridge assembly for the delta process along with the coolant contained therein.

According to a further preferred embodiment of the invention, the following method steps are carried out to carry out the heating operation: -connecting the AC-and heat pump branch upstream to the refrigerant outlet of the heating condenser or hot gas radiator and downstream to the heat pump return branch, and

-closing a choke-or shutter device assigned to the exterior heat exchanger, thereby preventing the air flow through the exterior heat exchanger.

The advantage here is that in this case, the components and system parts already present for other functions can again be used for heating the supply air flow of the vehicle interior, without expensive and complicated modifications in the design of the refrigerating device being necessary. In this case, the AC-and heat pump branches and their existing air heat pump-expansion mechanism serve to expand the refrigerant to a low pressure level, while the passive air side flows through the external heat exchanger, where heat transfer from the ambient air to the refrigerant is prevented.

The different heating operations can be performed either in any combination or simultaneously together with the heat pump process of the refrigerant circuit.

In accordance with a further development, it is therefore provided that the heating operation is carried out by means of a heating branch, a reheating branch or an AC and heat pump branch using the water heat pump process by means of a refrigerator branch having a refrigerator and a refrigerator expansion device. The advantage here is that, on the one hand, at least one further heat source is actively coupled, and, on the other hand, the refrigerant compressor is brought to the maximum operating speed, and the heating capacity of the refrigeration device in the heat pump connection can be maximized.

A further advantageous embodiment provides that the heating operation is carried out by means of the AC and heat pump branch by means of an air heat pump process by means of a heating branch, a reheat branch or a refrigerator branch. The advantage here is that in this case, on the one hand, at least one further heat source is actively coupled, and on the other hand, the refrigerant compressor is brought to the maximum operating speed, and thus the heating power of the refrigerating appliance in the heat pump connection can be maximized.

Finally, it is also possible to carry out two heat pump operating modes simultaneously with heating operation by means of the heating branch or the heating-branch. The advantage here is that, once again, on the one hand, at least one further heat source is actively coupled, and on the other hand, the refrigerant compressor is brought to the maximum operating speed, and thus the heating power of the refrigerating appliance in the heat pump connection can be maximized.

Drawings

Further advantages and details of the invention emerge from the following description of a preferred embodiment with reference to the single figure 1. The figure shows a circuit diagram of a refrigeration device for a vehicle to explain an embodiment of the method according to the invention.

Detailed Description

The refrigerant circuit 1 of the refrigerating appliance 10 according to fig. 1 can be operated both in refrigerating appliance or cooling mode (AC operation for short) and in heat pump mode (WP operation for short) and has at least two evaporators, namely an evaporator 2 and a refrigerator 3, which is thermally coupled to the coolant circuit 3.0 for cooling a high-voltage battery, for example.

The refrigerant circuit 1 according to fig. 1 comprises the following components:

-a refrigerant compressor 4

An external heat exchanger 5 designed as a condenser or gas cooler, which has a heat pump expansion mechanism AE3 for its respective heat pump evaporator functioning as a heat pump for heating operation,

-an internal heat exchanger 6 for the heat exchange,

-a low-pressure side accumulator 7,

an internal evaporator branch 2.1 having an evaporator 2 designed as a front evaporator and an evaporator-expansion mechanism AE2 connected upstream,

a non-return valve R1 connected downstream of the evaporator 2, which non-return valve R1 is in fluid connection with the inlet side of the refrigerant compressor 4 through the accumulator 7 and a section of the low-pressure side of the internal heat exchanger 6,

a refrigerator branch 3.1 having a refrigerator 3, a refrigerator expansion arrangement AE1 connected upstream of the refrigerator, wherein the refrigerator 3 is used for cooling electrical components of, for example, a vehicle, and for performing a hydrothermal pump function using waste heat of at least one electrical component,

an AC and heat pump branch 5.1 with an exterior heat exchanger 5 and a heat pump expansion element AE3, wherein in heating operation the AC and heat pump branch 5.1 is fluidically connected upstream via the heat pump expansion element AE3 to the interior evaporator branch 2.1 forming a node K4 and downstream via a closure element A2 to the inlet side of the refrigerant compressor 4, and in AC operation the AC and heat pump branch 5.1 is fluidically connected upstream via the closure element A4 to the high-pressure outlet power of the refrigerant compressor 4,

a heating branch 8.1 with a heating condenser 8 or a hot-gas radiator 8, which heating condenser 8 or hot-gas radiator 8 directly or indirectly heats a supply air flow L for the vehicle interior, wherein the heating branch 8.1 is fluidically connectable upstream via a latching mechanism A3 with the high-pressure outlet of the refrigerant compressor 4 and downstream via a latching mechanism A1 with a node K4 and further with the interior evaporator branch 2.1 and the AC and heat pump branch 5.1,

a reheat branch 5.2 with a reheat expansion mechanism AE4 designed as an expansion valve, wherein the reheat branch 5.2 is fluidly connected downstream with an external heat exchanger 5 forming a node K5 and upstream with a condenser 8 or a hot gas radiator 8,

a heat pump return branch 5.3 with a blocking mechanism A2 and a check valve R2, wherein the heat pump return branch 5.3 is fluidly communicable upstream with an external heat exchanger 5 via a node K5 and downstream with an accumulator 7 via a node K3,

a heating branch 8.2 comprising a heating-expansion mechanism AE5, wherein the heating branch 8.2 fluidly connects the refrigerant outlet KA with the heat pump return branch 5.3 by means of a node K1 via a node K2, which node K1 establishes a connection to the reheating-branch 5.2 and to the AC-and heat pump branches 2 via a latching mechanism A1, wherein the node K2 connects the latching mechanism A2 with the non-return valve R2, and

an electric heating element 9, which is designed, for example, as a high-voltage PTC heating element, as a direct or indirect heater for the supply air flow L introduced into the vehicle interior, which in this embodiment is located in the air conditioner 1.1 together with the heating condenser 8 or the hot-gas radiator 8 and the evaporator 2 and is connected on the air side to the heating condenser 8 or the hot-gas radiator 8 and thus also downstream of the evaporator 2, and

a controllable choke-or shutter device 5.5 connected upstream of the exterior heat exchanger 5 on the air side, which can be adjusted between an open position, in which the exterior heat exchanger 5 can be maximally loaded by the air flow L1, and a closed position, in which no air flow L1 flows through the exterior heat exchanger 5.

As sensors, a plurality of pressure/temperature sensors pT1, pT2, pT3, pT4 and pT5 are provided in the refrigerant circuit 1 according to fig. 1 for controlling and regulating the system.

The refrigerant compressor 4 is therefore assigned a first pressure/temperature sensor pT1 at the high-pressure outlet, a second pressure/temperature sensor pT2 at the outlet of the accumulator 7, a third pressure/temperature sensor pT3 at the outlet of the external heat exchanger 5, a fourth pressure/temperature sensor pT4 at the outlet of the heating capacitor 8 or the hot-gas radiator 8, and finally a fifth pressure/temperature sensor pT5 at the outlet of the low-pressure side of the refrigerator 3. Since the respective functions of these pressure-temperature sensors are known to those skilled in the art, they will not be described in detail.

With two blocking mechanisms A3 and A4, depending on the state of the two blocking mechanisms, the refrigerant flow is conducted from the high-pressure side of the refrigerant compressor 4 into the exterior heat exchanger 5, either when the blocking mechanism A4 is open and the blocking mechanism A3 is blocked, or into the heating branch 8.1 when the blocking mechanism A3 is open and the blocking mechanism A4 is blocked.

The heating operation of the refrigerant circuit 1 according to fig. 1 will be described below.

In the heating mode of the refrigerant circuit 1, the closure mechanism A4 is closed and the closure mechanism A3 is opened when the exterior heat exchanger 5 is used as a heat pump evaporator to realize an air-heat pump or when the refrigerator 3 is used to realize a water-heat pump, so that hot refrigerant can flow into the heating branch 8.1.

In order to perform the heating function by means of the exterior heat exchanger 5 as an air-heat pump evaporator, the refrigerant compressed by means of the refrigerant compressor 4 flows through the open latching mechanism A3 to output heat into the supply air stream L conducted into the passenger compartment into the heating condenser 8 or the hot-gas radiator 8 and is subsequently expanded via the open latching mechanism A1 into the exterior heat exchanger 5 by means of the heat pump-expansion mechanism AE3 to absorb heat from the ambient air and then flows back through the heat pump return branch 5.3 to the refrigerant compressor 4 when the latching mechanism A2 is fully open. At the same time, expansion mechanisms AE1, AE2, and AE4 remain closed, and heater-expander mechanism AE5 remains closed as well.

In the air-heat pump process by means of the exterior heat exchanger 5, heat is extracted from the air flow L1 conducted via the exterior heat exchanger 5 and transferred to the refrigerant.

The heating operation using the refrigerator 3 as a heat source is described below.

In order to perform the heating function by means of the refrigerator 3, the refrigerant compressed by the refrigerant compressor 4 flows through the opened closure mechanism A3 in order to dissipate heat into the supply air flow L to the vehicle interior, enters the heating condenser 8 or the hot-gas refrigerator 8, and is then expanded via the opened closure mechanism A1 and the node K4 into the refrigerator 3 by means of the refrigerator expansion mechanism AE1 for absorbing the waste heat of the electrical and/or electronic components arranged in the coolant circuit 3.0. In this heating function, the expansion mechanisms AE3 and AE4 and the heating-expansion mechanism AE5 are closed. The closure mechanism A2 of the heat pump return branch 5.3 is completely open, so that the refrigerant removed in the water heat pump process is sucked out of the AC and heat pump branch 5.1 via the closure mechanism A2 and is conveyed via the non-return valve R2 into the reservoir 7.

In addition to such heating operation by means of an air-heat pump or by means of a water-heat pump, in which both processes can also be carried out simultaneously, i.e. in combination, it is also possible to carry out the heating operation in different configurations of the components of the refrigerant circuit 1. In this heating operation, only the refrigerant compressor 4 is used as a heat source, and its driving power transmitted to the refrigerant is transmitted into the heat sink, that is to say ultimately directly or indirectly to the supply air stream L. This configuration for carrying out the heating operation is also referred to as a triangular process.

In the first heating mode, which is an indirect delta process, the heating condenser 8 or the hot-gas radiator 8 and the refrigerator 3 are used as components of the refrigerant circuit 1, wherein the refrigerator 3 is inoperative, i.e. on the secondary side in the coolant circuit 3.0, the coolant (e.g. water) is not circulated.

In order to carry out this first heating operation, the refrigerant compressed by the refrigerant compressor 4 flows into the heating branch 8.1 with the closure element A3 open and the closure element A4 closed, and then passes through the open closure element A1 into the refrigerator branch 3.1, wherein the refrigerant is expanded to a low pressure by means of the refrigerator expansion device AE1 as a heating-expansion device before being fed back to the refrigerant compressor 4 via the node K3, the accumulator 7 and the internal heat exchanger 6. In this first heating operation, the refrigerant outlet KA of the heating condenser 8 or the hot-gas radiator 8 is connected to a refrigerator-expansion mechanism as a heating-expansion mechanism. The evaporator expansion mechanism AE2, the heat pump expansion mechanism AE3, the reheat-expansion mechanism AE4, and the heat-expansion mechanism AE5 are turned off.

A water-heat pump function is present if the coolant circulates on the secondary side of the refrigerator 3 and cooling of the coolant is also allowed on the system side.

In the second heating mode, which is a direct delta process, the heating condenser 8 or the hot-gas radiator 8 and the heating branch 8.2 are used, which is achieved in that the refrigerant compressed by the refrigerant compressor 4 flows into the heating condenser 8 or the hot-gas radiator 8 of the heating branch 8.1 when the closure mechanism A3 is open and the closure mechanism A4 is closed and then flows into the heating branch 8.2 via the node K1 when the closure mechanism A1 is closed and the reheat expansion mechanism AE4 is closed, wherein the refrigerant is expanded to a low pressure by means of the heating expansion mechanism A5 before flowing back to the refrigerant compressor 4 via the node K2, the non-return valve R, the node K3, the reservoir 7 and the internal heat exchanger 6.

In order to carry out this second heating operation, the line cross-sections of the refrigerant lines between the nodes K1, K2 and K3 correspond to the standard dimensions of the refrigerant circuit 1.

In the third heating operation as a direct delta process, the condenser 8 or the hot-gas radiator 8 and the reheat-expansion mechanism AE4 are used as components. For this purpose, the refrigerant compressed by the refrigerant compressor 4 is conducted through the opened closure element A3 into the heating branch 8.1 with the closure element A4 closed, so that the refrigerant can flow from the heating condenser 8 or the hot-gas radiator 8 into the reheat branch 5.2 when the closure element A1 is closed. There, it is expanded by a reheat expansion mechanism AE4 as a heat expansion mechanism via a node K5 into the heat pump return branch 5.3 when the closure mechanism A2 is open, in order then to return into the refrigerant compressor 4 via the node K2, the non-return valve R2, the accumulator 7 and the internal heat exchanger 6. In this third heating operation, the refrigerant outlet KA of the heating condenser 8 or the hot-gas radiator 8 is connected to the reheat-expansion mechanism AE4 as a heating-expansion mechanism. Heating-expansion mechanism AE5 is closed.

Due to the low pressure level at node K5, no separate latching mechanism is required at the refrigerant inlet of the exterior heat exchanger 5. Due to the low pressure level, an evaporation temperature, which is usually lower than the ambient temperature, occurs in the exterior heat exchanger 5, whereby the air flow L1 flowing through the exterior heat exchanger 5 evaporates the refrigerant stored therein and it is thus present in the "superheated gas phase".

However, a blocking mechanism may be provided at the coolant inlet of the exterior heat exchanger 5 if necessary.

In the fourth heating operation as an indirect delta process, the heating condenser 8 or the hot-gas radiator 8 and the exterior heat exchanger 5 are used as an assembly. For this purpose, the refrigerant compressed by the refrigerant compressor 4 flows into the heating condenser 8 or the hot-gas radiator 8 of the heating branch 8.1 when the closure mechanism A3 is open and the closure mechanism A4 is closed, and then flows into the AC and heat pump branch 5.1 when the closure mechanism A1 is open, with the chiller expansion mechanism AE1 and the evaporator expansion mechanism AE2 being closed. With the aid of the heat pump expansion mechanism AE3 as a heating expansion mechanism, the refrigerant is expanded at low pressure into the external heat exchanger 5 and then guided through the node K5 into the heat pump return branch 5.3 when the closure mechanism A2 is open, so that the refrigerant can return to the refrigerant compressor 4 through the node K2, the non-return valve R2, the node K3, the accumulator 7 and via the internal heat exchanger 6. Also in this fourth heating operation, the refrigerant outlets KA of the heating condenser 8 and the hot-gas radiator 8 are connected to a heat pump-expansion mechanism AE3 as a heating-expansion mechanism.

Furthermore, in this fourth heating operation, the controllable choke or shutter device 5.5 is closed, so that the air flow L1 cannot flow via the exterior heat exchanger 5, and thus the active heat exchanger from the ambient air to the exterior heat exchanger 5 and thus the refrigerant is prevented. In this way, at the exterior heat exchanger 5, when the choke-or shutter device 5.5 at the front of the vehicle is closed, "still air" is generated on the exterior heat exchanger 5.

Each of these heating operations can be combined, if necessary, with an air heat pump process to be performed by means of the external heat exchanger 5 and/or a water-heat pump process to be performed by means of the refrigerator 3.

Thus, the second heating operation may be combined with the water-heat pump process as a direct triangular process. For this purpose, the refrigerant flows out of the heating condenser 8 or the hot-gas radiator 8 via its refrigerant outlet KA through the node K1, into the heating branch 8.2 and subsequently into the heat pump return branch 5.3, where it is expanded to a low pressure by the heating-expansion mechanism AE 5. Meanwhile, when the latch mechanism A1 is opened, the refrigerant from the refrigerant outlet KA of the heating condenser 8 or the hot gas radiator 8 is expanded into the refrigerator 3 by means of the refrigerator-expansion mechanism AE1 to absorb heat. The two refrigerant flows from the reheat-branch 5.2 and the refrigerator 3 are joined in the node K3 and returned to the refrigerant compressor 4.

Furthermore, the tertiary heating operation may be combined with the water-heat pump process as a direct triangular process. For this purpose, the refrigerant flows from the refrigerant outlet KA of the condenser 8 or the hot-gas radiator 8 via the reheat branch 5.2 into the heat pump return branch 5.3, wherein the refrigerant is expanded to a low pressure by means of the reheat expansion mechanism AE4 as a heating expansion mechanism. Meanwhile, when the latch mechanism A1 is opened, the refrigerant from the heating condenser 8 or the hot gas radiator 8 is expanded into the refrigerator 3 by means of the refrigerator-expansion mechanism AE 1. The two refrigerants from the reheat branch 5.2 and the refrigerator 3 are joined in the node K3 and returned to the refrigerant compressor 4.

Finally, the fourth heating operation can also be combined as an indirect delta process with a water-heat pump process. For this purpose, when the closure mechanism A1 is open (reheat expansion mechanism AE4 is closed), the refrigerant flows from the refrigerant outlet KA of the heating condenser 8 or of the hot-gas radiator 8 into both the AC-and heat pump branch 5.1 and the refrigerator branch 3.1. Here, when the choke or shutter 5.5 is closed, the refrigerant is expanded at low pressure into the exterior heat exchanger 5 by means of the heat pump expansion mechanism AE3 as a heating-expansion mechanism, and in order to absorb heat from the coolant, the refrigerant is expanded into the refrigerator 3 by means of the refrigerator expansion mechanism AE 1. The two partial flows merge at node K3 and return again to the refrigerant compressor 4.

In the following, a combination of a heating operation and an air-heat pump process is described.

Therefore, the first heating operation may be combined with the air-heat pump process as an indirect delta process. For this purpose, with the closure A1 open (reheat expansion mechanism AE4 closed), the refrigerant is conducted both into the refrigerator branch 3.1 and into the AC and heat pump branch 5.1. If the refrigerator 3 is not operating, i.e. the coolant in the coolant circuit 3.0 is stationary, the refrigerant is expanded to a low pressure by means of the refrigerator expansion mechanism AE1 as a heating-expansion mechanism, while the refrigerant in the AC-and heat pump branch 5.1 is expanded at a low pressure by means of the heat pump expansion mechanism AE3 into the exterior heat exchanger 5 to absorb heat from the ambient air. The controllable choke or shutter device 5.5 is, of course, open here.

Furthermore, the second heating operation can also be combined as a direct delta process with the air-heat pump process. For this purpose, a partial flow of the refrigerant flows on the one hand from the refrigerant outlet KA of the condenser heater 8 or the hot-gas radiator 8 via the node K1 into the heating branch 8.2, where it is expanded to a low pressure by the heating-expansion mechanism AE5, while another partial flow of the refrigerant flows via the open closure mechanism A1 (the reheat-expansion mechanism AE4 is closed) into the AC and heat pump branch 5.1, where it is expanded by the heat pump expansion mechanism AE3 into the external heat exchanger 5 for absorbing heat.

Finally, the third heating operation can also be combined as a direct delta process with the air-heat pump process. For this purpose, a partial flow of the refrigerant flows out of the refrigerant outlet KA of the heater condenser 8 or the hot-gas heat sink 8 into the reheat branch 5.2, while another partial flow of the refrigerant flows out of the refrigerant outlet KA of the heater condenser 8 or the hot-gas heat sink 8 into the AC and heat pump branch 5.1 via the opened closure mechanism A1. By means of the reheat-expansion mechanism AE4 as a heating-expansion mechanism, a part flow of the refrigerant is expanded to a low pressure and flows via the node K5 into the heat pump return branch 5.3, while another part flow of the refrigerant is expanded by means of the heat pump-expansion mechanism AE3 into the exterior heat exchanger 5 to absorb heat. The two partial flows are joined together at node K5. The evaporator-expansion mechanism AE2 and the heating-expansion mechanism AE5 are closed.

Another combination possibility provides that the heating operation is carried out simultaneously with the water heat pump process and the air heat pump process.

The second heating operation to be carried out via the heating branch 8.2 can therefore be carried out simultaneously with both the water-heat pump process and the air-heat pump process. For this purpose, the refrigerant flowing out of the heating condenser 8 or the hot-gas radiator 8 via its refrigerant outlet KA is divided into three partial flows. A first partial flow is conducted into the heating branch 8.2 for carrying out the heating operation, a second partial flow is conducted through the opened latching mechanism A1 into the refrigerator branch 3.1 for carrying out the water heat pump process, and a third partial flow is conducted through the opened latching mechanism A1 into the AC and heat pump branch 5.1 for carrying out the air heat pump process.

Another possibility consists in combining the third heating operation to be carried out by the reheat branch 5.2 simultaneously with both the water-heat pump process and the air-heat pump process. For this purpose, the refrigerant flowing out of the heating condenser 8 or the hot-gas radiator 8 via its refrigerant outlet KA is divided into three partial flows. A first partial flow is conducted into the reheat branch 5.2 for the heating operation, a second partial flow is conducted through the open latching mechanism A1 into the refrigerator branch 3.1 for the water heat pump process, and a third partial flow is conducted through the open latching mechanism A1 into the AC and heat pump branch 5.1 for the air heat pump process.

Another combination possibility consists in combining the individual heating operations with one another.

Thus, a third heating operation to be performed by the reheat branch 5.2 and a fourth heating operation to be performed by means of the AC-and heat pump branch 5.1 can be performed simultaneously, wherein the fourth heating operation can be performed with the choke or shutter device 5.5 closed.

Another possibility is to carry out a third heating operation to be carried out by means of the reheating branch 5.2 and a first heating operation to be carried out by means of the refrigerator branch 3.1 simultaneously.

Furthermore, a first heating operation to be carried out by means of the refrigerator branch 3.1 and a fourth heating operation to be carried out by means of the AC and heat pump branches can be combined, the fourth heating operation being to be carried out with the choke or shutter device 5.5 closed.

Furthermore, the two direct trigonometric processes as heating mode can also be carried out simultaneously, namely a heating mode by means of the heating branch 8.2 (second heating mode) and a heating mode by means of the reheating branch 5.2 (third heating mode).

The second heating operation by means of the heating branch 8.2 and the fourth heating operation by means of the AC and heat pump branch 5.1 can also take place simultaneously, the fourth heating operation being to be carried out with the choke or shutter 5.5 arrangement closed.

Finally, the second heating operation to be carried out by means of the heating branch 8.2 can be combined with the first heating operation to be carried out by means of the refrigerator branch 3.1.

Six different pairwise combinations of four heating operations result from this.

A further advantageous combination possibility consists in combining a third heating operation to be carried out by means of the reheating branch 5.2, a fourth heating operation to be carried out by means of the AC and heat pump branch 5.1 (when the damper or shutter device 5.5 is closed) and a first heating operation to be carried out by means of the refrigerator branch 3.1 when the refrigerator 3 is not in operation. Thereby performing three different heating operations. In addition to these three simultaneous heating operations, it is also possible to combine the second heating operation to be performed by means of the heating branch 8.2, so that all four heating operations described are performed simultaneously as a four-combination.

Further three combinations of the four heating runs include: a combination of a first heating operation, a second heating operation, and a third heating operation; another combination of the second heating operation, the third heating operation, and the fourth heating operation; and finally the last combination of the first heating run, the second heating run, and the fourth heating run. Thus, there are four three-in-one combinations of four heating runs in total.

Another possibility consists in combining at least two heating operations with an air-heat pump process to be carried out by means of the external heat exchanger 5 and/or a water-heat pump process to be carried out by means of the refrigerator 3.

Thus, it is possible to combine the first and third heating operations with the air-heat pump process, the first and second heating operations with the air-heat pump process, and finally the third and fourth heating operations with the air-heat pump process.

The water-heat pump process can be combined with either the third and fourth heating operations, the second and fourth heating operations, or the second and third heating operations.

Finally, the three-part combination of heating operations can be combined with an air-heat pump process or a water-heat pump process.

Therefore, the first, second and third heating operations may be combined with the air-heat pump process, or the second, third and fourth heating operations may be combined with the water-heat pump process.

In the combinations of these listed heating operations, or the combination of the heating operation with the indirect delta process and the (still) inactive components for heat transfer in the actual heat pump process, i.e. with the second heating operation to be carried out by means of the refrigerator branch 3.1 and/or the fourth heating operation to be carried out by means of the AC and heat pump branch 5.1, it is possible to switch directly from the heating operation to the heat pump process, i.e. to the water-heat pump process and/or the air-heat pump process.

The refrigerating appliance 10 can also be designed with a refrigerant circuit 1, wherein the node K1 migrates into a node K1 of the heating branch 8.1 between the latching mechanism A3 and the heating condenser 8 or the hot-gas radiator 8, and the heating-expansion mechanism AE5 is replaced by a latching mechanism A5. In this variant, therefore, the suction branch 5.4 formed between the node K1 and the node K2 serves to draw refrigerant out of the heating branch 8.1 only when AC operation is carried out. Even in such a refrigerant circuit 1, the above-described heating operations, i.e., the first, third and fourth heating operations and the above-described combination with the air-and water-heat pump process, can be performed.

The following describes the reheat operation performed by the refrigerating appliance 10, which can be performed both with the refrigerant circuit 1 having the heating branch 8.2 according to fig. 1 and with the refrigerant circuit 1 having the suction branch 5.4 according to fig. 1.

In the reheating mode, the supply air stream L fed to the vehicle interior is first cooled by the evaporator 2 and simultaneously dehumidified, in order to subsequently reheat the supply air stream L at least partially again by means of the heating condenser 8 or the hot-gas radiator 8, using the heat extracted from the supply air stream L and the heat supplied to the refrigerant by the refrigerant compressor 4.

The reheat operation of the refrigerant circuit 1.1 is performed in different ways based on the heat balance.

Therefore, in the case of sufficient heating power in the refrigerant circuit 1, the refrigerant flows only through the evaporator 2 by the heating condenser 8 or the hot-gas radiator 8 being fluidically connected downstream via the evaporator-expansion mechanism AE2 to the evaporator 2 by means of the open blocking mechanism A1, with the refrigerator-expansion mechanism AE1 being blocked. From the evaporator 2, the refrigerant flows back again via the non-return valve R1, the accumulator 7 and the internal heat exchanger 6 to the refrigerant compressor 4, wherein the heat absorbed in the evaporator 2 together with the hot flow entering via the refrigerant compressor 4 is released again via the heating condenser 8 or the hot-gas radiator 8 into the supply air flow L introduced into the vehicle interior. The expansion devices AE1, AE3 and AE4 are completely closed here.

When there is a lack of heat in the refrigerant circuit 1.1, in order to absorb the heat, in addition to the evaporator 2, the refrigerator 3 is connected in parallel by opening the refrigerator-expansion mechanism AE1 and/or the exterior heat exchanger 5 is connected in parallel by opening the heat pump-expansion mechanism AE3.

When the heat is excessive in the reheating-operation, the heat is radiated to the environment of the vehicle by the exterior heat exchanger 5 before the refrigerant is returned again to the refrigerant compressor 4 via the evaporator 2, in addition to the supply air flow L that radiates the heat to the passenger compartment through the heating condenser 8 or the hot-gas radiator 8. For this purpose, the refrigerant is expanded at an intermediate pressure above the evaporation pressure by means of the reheat expansion mechanism AE4 of the reheat branch 5.2 for condensation and subsequently expanded to a low pressure into the evaporator 2 by means of the evaporator expansion mechanism AE 2.

For the sake of completeness, the AC operation of the refrigerant circuit 1 of the refrigeration appliance 10 according to fig. 1 is also explained.

In AC operation, the heating branch 8.1 is blocked by the blocking mechanism A3, so that no hot refrigerant (e.g. R744) can flow through the hot-gas radiator condenser 8 or the hot-gas radiator 8. In order to recover the refrigerant from the inactive heating branch 8.1, the heating-expansion mechanism AE5 of the heating branch 8.2 or the closure mechanism A5 of the suction branch 5.4 is opened and the refrigerant can flow in the direction of the reservoir 7 through the heating-expansion mechanism AE5 or through the closure mechanism A5 and the non-return valve R2 while the closure mechanism A2 is closed.

In AC operation of the refrigerant circuit 1, the refrigerant compressed under high pressure flows from the refrigerant compressor 4 into the exterior heat exchanger 5, into the high-pressure section of the interior heat exchanger 6, through the fully open heat pump expansion mechanism AE3 and the first node K4 into the evaporator branch 2.1 and/or into the refrigerator branch 3.1 when the closure mechanism A4 is open. From the refrigeration branch 3.1, the refrigerant flows back to the refrigerant compressor 4 via the reservoir 7 and the low-pressure section of the internal heat exchanger 6, while from the evaporator branch 2.1 the refrigerant can flow through the non-return valve R1 and then again through the reservoir 7 and the low-pressure section of the internal heat exchanger 6 likewise back to the refrigerant compressor 4.

List of reference numerals

1. Refrigerant circuit of refrigeration device 10

1.1 Air conditioner

2. Evaporator with a heat exchanger

2.1 Inner chamber evaporator branch

3. Refrigerating device

3.0 Coolant circuit of a refrigerator 3

3.1 Refrigerator branch

4. Refrigerant compressor

5. External heat exchanger

5.1 AC-and heat pump branch

5.2 Reheating branch

5.3 Heat pump return branch

5.4 Suction branch

5.5 Choke and shutter device for an exterior heat exchanger 5

6. Internal heat exchanger

7. Storage device

8. Heating condensers or hot-gas radiators

8.1 Heating branch

8.2 Heating branch

9. Electric heating element

10. Refrigeration device

A1 Locking mechanism

A2 Locking mechanism

A3 Locking mechanism

A4 Locking mechanism

A5 Locking mechanism

K1 Branch point

K1 branch point

K2 Branch point

K3 Branch point

K4 Branch point

K5 Branch point

AE1 refrigerator-expansion mechanism

AE2 evaporator-expansion mechanism

AE3 heat pump-expansion mechanism

AE4 reheating-expanding mechanism

AE5 heating-expansion mechanism

L supply air flow

L1 gas flow

pT1 first pressure-temperature sensor

pT2 second pressure-temperature sensor

pT3 third pressure and temperature sensor

pT4 fourth pressure-temperature sensor

pT5 fifth pressure-temperature sensor

R1 check valve

R2 check valve

Claims

1. Method for operating a refrigeration device (10) of a vehicle with a refrigerant circuit (1) having a heat pump function, having the following components:

-a refrigerant compressor (4) having a high pressure outlet and an inlet side,

-an AC-and heat pump branch (5.1) with an external heat exchanger (5) which can be operated either as a condenser or as a gas cooler or as a heat pump-evaporator, and a heat pump-expansion mechanism (AE 3) which can be used for the heat pump function, wherein the AC-and heat pump branch (5.1) can be connected to the high-pressure outlet of the refrigerant compressor (4),

-a heating branch (8.1) with a heating condenser (8) or a hot gas radiator (8) which directly or indirectly heats a supply air stream (L) for the vehicle interior, wherein for implementing the heat pump process the heating branch (8.1) is connectable upstream to a high pressure outlet of the refrigerant compressor (4) and downstream to an AC-and heat pump branch (5.1),

-an evaporator branch (2.1) with an evaporator (2) and an evaporator-expansion mechanism (AE 2), wherein the evaporator branch is connectable to the inlet side of a refrigerant compressor (4) on the low pressure side and to an AC-and heat pump branch (5.1) on the high pressure side, and

-a heat pump return branch (5.3) with a blocking mechanism (A2) connectable upstream to an external heat exchanger (5) and downstream to an inlet side of a refrigerant compressor (4),

wherein, in order to implement heating operation

-the high-pressure outlet of the refrigerant compressor (4) is connected to the heating branch (8.1), and

the refrigerant outlet (KA) of the heating condenser (8) or of the hot gas radiator is directly connected to the heat pump return branch (5.3) by means of a heating branch (8.2) comprising a heating-expansion mechanism (AE 5), wherein the refrigerant is expanded to a low pressure by means of the heating-expansion mechanism (AE 5);

and/or

The refrigerant outlet (KA) of the condenser heater (8) or of the hot-gas radiator is directly connected to the heat pump return branch (5.3) by means of a reheat branch (5.2) having a reheat-expansion mechanism (AE 4), wherein the refrigerant is expanded to a low pressure by means of the reheat-expansion mechanism (AE 4) as a heat-expansion mechanism.

2. Method according to claim 1, wherein for carrying out the heating operation, the refrigerant outlet (KA) of the heating condenser (8) or the hot-gas radiator (8) is connected to a refrigerator branch (3.1) having a refrigerator (3) and a refrigerator expansion mechanism (AE 1), wherein the refrigerant is expanded to a low pressure using the refrigerator expansion mechanism (AE 1) as an additional expansion mechanism.

3. Method according to claim 1 or 2, wherein for carrying out a heating operation the following method steps are carried out:

-connecting the AC-and heat pump branch (5.1) upstream to the refrigerant outlet (KA) of the heating condenser (8) or the hot gas radiator (8) and downstream to the heat pump return branch (5.3), and

-closing a choke-or shutter device (5.5) assigned to the exterior heat exchanger (5), thereby preventing the air flow (L) through the exterior heat exchanger (5).

4. Method according to claim 1, wherein the water-heat pump process is carried out by means of a refrigerator branch (3.1) having a refrigerator (3) and a refrigerator-expansion mechanism (AE 1).

5. Method according to claim 1, wherein the air-heat pump process is carried out by means of an AC-and heat pump branch (5.1).