Method for operating a refrigeration device with heat pump function and heat source regeneration function, refrigeration device, and motor vehicle having such refrigeration device

Abstract

The present invention relates to a method (500) for operating a refrigeration device (10) with heat pump function for motor vehicles, the refrigeration device (10) comprising: a refrigerant compressor (12) connected to or capable of being connected to a primary branch (14) and a secondary branch (16); an external heat exchanger (18) acting directly or indirectly, arranged in the primary branch (14); an evaporator (22) arranged in the primary branch (14); at least one additional heat exchanger as a heat source, in particular a heated air conditioner (26), arranged in the secondary branch (16); a primary branch valve (A4) arranged between the refrigerant compressor (12) and the external heat exchanger (18); a secondary branch valve (A3) arranged between the refrigerant compressor (12) and the additional heat exchanger as a heat source; and a third heat exchanger (28), in particular a cryotherm, acting directly or indirectly as a water heat pump. Here, the method (500) includes the following steps: setting (S502) the heat pump to operate, wherein refrigerant is directed from the refrigerant compressor (12) to the secondary branch (16); adjusting (S503) the expansion valve (AE1) allocated to the third heat exchanger (28) so that the total mass flow of refrigerant flows through the third heat exchanger (28); detecting (S504) the temperature (Tkw) of the coolant in the third heat exchanger (28); wherein if the temperature (Tkw) of the coolant is greater than the upper limit temperature (Tgo), the total mass flow of refrigerant is directed through the third heat exchanger (28).

Description

Technical Field

[0001] The present invention relates to a method for operating a refrigeration device with heat pump function for a motor vehicle, a refrigeration device, and a motor vehicle having such a refrigeration device. Background Technology

[0002] Refrigeration equipment with heat pump function typically includes: a refrigerant compressor connected to or potentially connected to the primary and secondary branches; an external heat exchanger acting directly or indirectly, arranged in the primary branch; an evaporator arranged in the primary branch; at least one additional heat exchanger acting as a heat source, particularly a heated air conditioner / heated louvered vent, arranged in the secondary branch; a primary branch valve arranged between the refrigerant compressor and the external heat exchanger; and a secondary branch valve arranged between the refrigerant compressor and at least one additional heat exchanger, particularly a heated air conditioner.

[0003] Such a refrigeration device for motor vehicles with a heat pump function is known, for example, from documents DE 10 2019 203 295 A1 or US 2014 / 075966 A1. In this refrigeration device, different heat sources are switched or used depending on the limiting temperature of the heat source. Other refrigeration devices with multiple heat pumps are known, for example, from documents DE 10 2017 204 116 A1 and WO 2019 / 158316A1. Additionally, references are also made to documents DE 10 2013 206 630 A1, DE 10 2011 010 807 A1, and DE 10 2013 111 454A1.

[0004] The approach considered here focuses on the heat pump operation of refrigeration equipment, specifically the operation of heating the air supplied to the interior space and / or, in some cases, dehumidifying it.

[0005] When the heating power demand of such refrigeration equipment for motor vehicles is high, especially during cold starts, for example, when the heat source cools the coolant very quickly—that is, the heat extracted from the coolant is greater than the heat input to the coolant, for example, in the form of waste heat from an electrical storage device or load—the refrigerant of the refrigeration equipment then extracts the absorbed waste heat from the coolant, resulting in lower efficiency or heating power of the heat pump. It should also be considered in particular that highly efficient electrical components cooled by a coolant, such as cooling water (a water-glycol mixture), may not provide sufficient (waste) heat replenishment to the coolant to maintain a temperature suitable for efficient, especially high-performance, operation. Summary of the Invention

[0006] The object of this invention is to provide a method in which overcooling of the heat source used for evaporating the refrigerant, especially the cooling medium, is avoided. This should optimize overall energy consumption, and in particular, improve electrical energy consumption.

[0007] This objective is achieved by a method, refrigeration equipment, and motor vehicle having the features of the corresponding independent patent claims. Advantageous designs and suitable improvements are given in the dependent patent claims.

[0008] Therefore, a method is proposed for operating a refrigeration device with heat pump function for motor vehicles, wherein the refrigeration device includes: a refrigerant compressor connected to or potentially connected to a primary branch and a secondary branch; an external heat exchanger, acting directly or indirectly, arranged in the primary branch; an evaporator, arranged in the primary branch; at least one additional heat exchanger, particularly a heated air conditioner, acting as a heat source, arranged in the secondary branch; a primary branch valve arranged between the refrigerant compressor and the external heat exchanger; a secondary branch valve arranged between the refrigerant compressor and the additional heat exchanger, particularly the heated air conditioner, acting as a heat source; and a third heat exchanger, particularly a chiller, operating as a water heat pump and acting directly or indirectly. The method is specified to include the following steps:

[0009] Start / set up heat pump operation, in which refrigerant is diverted from the refrigerant compressor to the secondary branch;

[0010] The expansion valves are adjusted to distribute to the third heat exchanger, especially the cryogenic cooler, so that the total mass flow of the refrigerant flows through the third heat exchanger and evaporates in the third heat exchanger by the residual heat of the coolant circulating in the third heat exchanger.

[0011] Detect the temperature of the coolant in or at the third heat exchanger;

[0012] If the temperature of the coolant is higher than the upper limit temperature, the total mass flow of the refrigerant will be directed through the third heat exchanger.

[0013] By monitoring the coolant temperature, it can be ensured that when the coolant still has sufficient potential to deliver heat and evaporate, the entire mass flow of refrigerant is directed only through the third heat exchanger. Furthermore, this ensures that the coolant is not cooled to a degree by heat extraction in the third heat exchanger, preventing it from being adequately reheated in its coolant circuit by residual heat from, for example, electrical components of the vehicle.

[0014] Another reason why the coolant should not be overcooled is that as the coolant temperature decreases, the viscosity of the coolant increases, and therefore an interruption in the coolant volume flow may occur. As a result, the required or demanded minimum volume flow can no longer be guaranteed.

[0015] In this method, the expansion valve allocated to the external heat exchanger is adjusted so that a portion of the mass flow passes through the external heat exchanger, which operates as an air heat pump. Simultaneously, the expansion valve allocated to the third heat exchanger is adjusted so that a portion of the refrigerant mass flow continues through the third heat exchanger. By connecting another heat source (ambient air) to evaporate the refrigerant in the external heat exchanger, the temperature drop in the coolant can be mitigated or stopped. Furthermore, this measure can also restore the coolant temperature level. Therefore, the heating power balance of the entire system can be achieved. In addition, it can be ensured that the heating power provided by the heated air conditioner for the vehicle's interior space (cabin) is not significantly interrupted.

[0016] In this method, the expansion valve allocated to the external heat exchanger can be opened at least partially based on the temperature difference between the coolant in the third heat exchanger, particularly the cryogenic cooler, and the lower limit temperature, especially when the difference is 2 K (Kelvin) or lower. This ensures timely connection of the external heat exchanger, preventing overcooling of the coolant due to heat transfer to the refrigerant.

[0017] A portion of the refrigerant's mass flow through the external heat exchanger can be maintained until the refrigerant temperature reaches or exceeds the upper limit temperature. In other words, the external heat exchanger can be kept on until the refrigerant temperature level is high enough that, at least for a certain period of time, the refrigerant will no longer be overcooled due to heat transfer to the refrigerant.

[0018] In this method, upper and lower temperature limits can be selected based on the detected ambient temperature. This ensures that appropriate limit temperatures can be selected and set at different ambient temperatures, for example from -5°C to 15°C, so that the described method can be executed via a third heat exchanger (water heat pump) and, if necessary, an external heat exchanger acting as an air heat pump.

[0019] Alternatively or as a supplement, the upper and lower temperature limits can be selected based on the detected relative humidity of the environment.

[0020] As an alternative, the coolant limit temperature can be set such that it also guarantees the minimum permissible flow rate of the coolant and, consequently, the volumetric flow rate of the coolant.

[0021] In this method, the upper and lower limit temperatures can be selected based on the possible temperature difference between the ambient temperature and the refrigerant temperature in the external heat exchanger during the operation of the refrigeration equipment. Here, the expansion valve allocated to the external heat exchanger can be adjusted such that the refrigerant temperature at the inlet into the external heat exchanger is less than or at most equal to the ambient temperature, but particularly 1K to 5K lower than the ambient temperature.

[0022] In this method, the expansion valve allocated to the external heat exchanger can be closed based on the difference between the temperature of the coolant in the third heat exchanger, especially the cryogenic cooler, and the lower limit temperature, particularly when the difference is greater than 5K. In other words, if the temperature of the coolant has moved sufficiently away from the lower limit temperature, the air heat pump can be shut off again and the total mass flow of the refrigerant can be directed only through the third heat exchanger once more.

[0023] In this method, alternatively or additionally, at least one electric heating element may be activated based on the difference between the temperature of the refrigerant in the third heat exchanger, especially the cryogenic cooler, and the lower limit temperature, particularly when the difference is 2K or lower, so as to heat the refrigerant upstream or downstream of the third heat exchanger.

[0024] Here, the electric heating element can be shut down based on the difference between the temperature of the coolant in the third heat exchanger, especially the cryogenic cooler, and the lower limit temperature, particularly when the difference is greater than 5K.

[0025] Alternatively, it is conceivable that by (temporarily) reducing the efficiency of the electric drive, especially during periods when critical coolant temperatures exist, additional heating power can be provided to the cooling fluid flow through heat loss, thereby supporting heated operation and maintaining and / or enhancing interior space comfort.

[0026] In this method, alternatively or additionally, at least a portion of the refrigerant mass flow may be directed downstream of another heat exchanger, particularly a heated air conditioner, bypassing the third heat exchanger and / or an external heat exchanger, to the low-pressure side based on the difference between the temperature of the refrigerant in the third heat exchanger, especially the cryogenic cooler, and the lower limit temperature, particularly when the difference is 2K or lower.

[0027] Here, the refrigerant's bypass mass flow around the third heat exchanger or / and the external heat exchanger can be terminated based on the difference between the temperature of the refrigerant in the third heat exchanger, especially the cryogenic cooler, and the lower limit temperature, particularly when the difference is greater than 5K.

[0028] A refrigeration device with heat pump function for motor vehicles is also proposed, wherein the refrigeration device includes: a refrigerant compressor connected to or potentially connected to a primary branch and a secondary branch; an external heat exchanger, acting directly or indirectly, arranged in the primary branch; an evaporator, arranged in the primary branch; at least one additional heat exchanger, particularly a heating fan, acting as a heat source, arranged in the secondary branch; a primary branch valve arranged between the refrigerant compressor and the external heat exchanger; a secondary branch valve arranged between the refrigerant compressor and the additional heat exchanger, particularly the heating fan, acting as a heat source; and a third heat exchanger, particularly a cryogenic cooler, operating as a water heat pump and acting directly or indirectly. It is specified that the refrigeration device has at least one temperature sensor configured to detect the coolant temperature in or at the inlet side of the third heat exchanger, particularly the cryogenic cooler, and the refrigeration device is configured to adjust the expansion valves allocated to the third heat exchanger and the external heat exchanger according to the detected coolant temperature.

[0029] Alternatively, at least one sensor on the cooling loop side can be arranged on the outlet side of the cryogenic cooler, because in this way, the temperature of the coldest cooling medium in the circulating fluid flow can be detected after heat has been transferred from the coolant to the refrigerant. Therefore, intervention on the regulating side of system function can be achieved, or will be achieved even earlier.

[0030] Here, the adjustment of the expansion valve includes not only a (partially) open state but also a closed state, through which refrigerant is prevented from flowing into the third heat exchanger or the external heat exchanger.

[0031] It should be noted that the closed state of the external heat exchanger can also be achieved by a shut-off valve or by a check valve, which is technically simpler to implement. The system should not be designed to use the external heat exchanger as an air heat pump evaporator or to present air heat pump functionality in the known implementation.

[0032] The refrigeration equipment may have at least one bypass section that branches off downstream from another heat exchanger, particularly a heated air conditioner, which connects to the upstream of the refrigerant compressor on the low-pressure side and forms a bypass section for the third heat exchanger and the external heat exchanger.

[0033] Here, a bypass expansion mechanism can be arranged in the bypass section, which is advantageously implemented as a bypass expansion valve.

[0034] Here, the bypass section can also be connected to the upstream of the refrigerant collector on the low-pressure side.

[0035] A particular advantage of this bypass section is that it enables a “short” triangular process in which the refrigerant is guided almost directly to the refrigerant compressor downstream of the heater, with little or no potential heat loss, because the bypass section establishes a short flow path for the refrigerant.

[0036] Alternatively or supplementally, the refrigeration equipment may have at least one electric heating element that is allocated to the refrigerant circuit and configured to heat the refrigerant as needed. Here, one or more such heating elements can raise the temperature level of the refrigerant, especially when the coolant fluid in the cryocooler cannot release sufficient heat to the refrigerant and therefore the water heat pump function cannot be utilized or cannot be optimally utilized, or when the water heat pump function cannot or must not be used due to thermal balance at other components incorporated into the coolant circuit.

[0037] In addition to the heating element integrated into the refrigerant circuit, a heating element can be optionally located on the air side, or this air-side heating element can be used to compensate for (temporary) insufficient heating until the water heat pump can resume its unrestricted operation.

[0038] If a heat exchanger loaded with coolant is installed on the air side downstream of the evaporator instead of a heating air conditioner, an electric heater can also be installed in the coolant fluid circuit supplying the coolant.

[0039] The refrigeration equipment may include a control device configured to perform the above-described method.

[0040] Motor vehicles, especially those that are at least partially powered by electricity, may have the aforementioned refrigeration equipment. In electric vehicles, the efficient operation of refrigeration equipment, especially in heating the interior space or cabin, can result in energy savings, thereby enabling electric vehicles to achieve a greater driving range.

[0041] Therefore, the method and refrigeration equipment proposed herein can prevent overcooling of the coolant (as a heat source for the refrigerant or refrigerant circuit), where the heat source is water or air, by alternately connecting or switching on at least two heat exchangers operating as evaporators. As a result, heating power can be balanced and stabilized for use in the interior space or compartment. In other words, a form of regeneration can be achieved for the heat source, i.e., the coolant, in which, on the one hand, the heat source is not further (overly) cooled, and on the other hand, the coolant can be reheated.

[0042] Instead of alternately switching on or connecting at least two heat exchangers operating as evaporators, a complete and 100% switch from one evaporator to a second evaporator can occur, thus avoiding the operation of the corresponding portions. For example, the system can switch from full water-heat pump operation to full air-heat pump operation, and vice versa. Attached Figure Description

[0043] Further advantages and details of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings.

[0044] in:

[0045] Figure 1 A schematic simplified circuit diagram of a refrigeration device for a motor vehicle is shown;

[0046] Figure 2 This was shown, especially by means of in Figure 1 A flowchart illustrating an exemplary method for implementing a refrigeration device;

[0047] Figure 3 A simplified diagram illustrating the coolant temperature limits is shown.

[0048] Figure 4 This was shown, especially by means of in Figure 1 A flowchart illustrating an exemplary method for implementing a refrigeration device;

[0049] Figure 5 This was shown, especially by means of in Figure 1 The flowchart illustrates the exemplary implementation method of the refrigeration equipment described herein. Detailed Implementation

[0050] exist Figure 1 The diagram schematically simplifies one embodiment of a refrigeration device 10 for a motor vehicle. The refrigeration device 10 includes a refrigerant circuit 11, which can operate not only in refrigeration device operation (also simply referred to as AC operation) but also in heat pump mode. In the illustrated embodiment, the refrigeration device 10 includes a refrigerant compressor 12, an external heat exchanger 18, an internal heat exchanger 20, an evaporator 22, and an accumulator or refrigerant collector 24. The external heat exchanger 18 may be configured as a condenser or a gas cooler. In the illustrated embodiment, the external heat exchanger 18 is particularly bidirectional.

[0051] Here, evaporator 22 is shown as an example of a front evaporator for a vehicle. Evaporator 22 may also represent other possible evaporators in a vehicle, such as a rear evaporator, which may be arranged in parallel with each other in terms of flow technology. That is, in other words, the refrigeration device 10 includes at least one evaporator 22.

[0052] A shut-off valve A4 is located downstream of compressor 12. An expansion valve AE2 is located upstream of evaporator 22.

[0053] Within the scope of this specification, the section from the compressor 12 to the external heat exchanger 18, to the internal heat exchanger 20, and to the evaporator 22 in the entire refrigerant circuit 11 of the refrigeration equipment 10 is referred to as the primary branch 14.

[0054] The refrigeration equipment 10 also includes a heated air conditioner 26 (also referred to as a heated condenser or heated gas cooler). A shut-off valve A3 is arranged upstream of the heated air conditioner 26. A shut-off valve A1 is arranged downstream of the heated air conditioner 26. In addition, an expansion valve AE4 is arranged downstream of the heated air conditioner 26.

[0055] Within the scope of this specification, the section in the entire refrigerant circuit of the refrigeration equipment 10 from the compressor 12 to the heater / air conditioner 26, to the expansion valve AE4, and to the branch point Ab2 is referred to as the secondary branch 16. The secondary branch 16 includes a heating branch 16.1 extending from the shut-off valve A3 via the heater / air conditioner 26 to the shut-off valve A1. The secondary branch 16 also includes a reheating branch 16.2, which may be fluidly connected upstream to the heater / air conditioner 26 and downstream to the external heat exchanger 5. Here, the secondary branch 16, more specifically the reheating branch 16.2, connects to the primary branch 14 at the branch point Ab2.

[0056] The refrigeration unit 10 includes another evaporator or cryocooler 28. The cryocooler 28 is arranged in parallel with the evaporator 22 in terms of flow technology. The cryocooler 28 can be used, for example, to cool electrical components of a vehicle, but can also be used to implement a water-heat pump function by utilizing the waste heat of at least one electrical component. An expansion valve AE1 is located upstream of the cryocooler 28.

[0057] The refrigeration unit 10 may also include an electric heating element 30, which may be implemented, for example, as a high-pressure PTC heating element. The electric heating element 30 serves as an additional heater for the airflow L directed into the vehicle's interior space. Here, the electric heating element 30 may be housed together with the heated air conditioner 26 and the evaporator 22 in the air conditioning unit 32. Here, the electric heating element 30 may be arranged rearward from the heated air conditioner 26.

[0058] In addition, Figure 1Check valves R1 and R2 can also be seen. Several sensors pT1 to pT5 for detecting the pressure and / or temperature of the refrigerant are also shown. It should be noted that the number of sensors and their arrangement are shown here only as an example. The refrigeration unit 10 may also have fewer or more sensors. The example shown illustrates a combination of pressure / temperature sensors pT1 to pT5 as sensors. However, it is equally conceivable to use independent sensors for measuring pressure and temperature, and to arrange these independent sensors spatially separated from each other along the refrigerant line, if necessary.

[0059] The refrigeration equipment 10 can operate in different modes, which will be briefly described below.

[0060] In AC operation of refrigerant circuit 11, with shut-off valve A4 open / closed, refrigerant compressed to high pressure flows from refrigerant compressor 12 to external heat exchanger 18. From there, the refrigerant flows to the high-pressure section of internal heat exchanger 20 and the fully open expansion valve AE3. Via branch point Ab1, the refrigerant can flow to expansion valve AE2 and into internal space evaporator 22 (evaporator section 22.1). In parallel or alternatively, the refrigerant can flow through branch point Ab4 and expansion valve AE1 to cryogenic cooler 28 (cryogenic cooler section 28.1). From evaporator 22 and / or cryogenic cooler 28, the refrigerant flows on the low-pressure side to collector 24 and returns to compressor 12 through the low-pressure section of internal heat exchanger 20.

[0061] During AC operation, heating branch 16.1 or secondary branch 16 is blocked by shut-off valve A3, preventing hot refrigerant from flowing through heater air conditioner 26. To recover refrigerant from inactive heating branch 16.1, shut-off mechanism A5, configured as a shut-off valve, can be opened, allowing refrigerant to flow towards collector 24 through shut-off mechanism A5 and check valve R2 while shut-off mechanism A2 is simultaneously closed / turned off.

[0062] During the heating operation of the refrigerant circuit 11, shut-off valve A4 is closed and shut-off valve A3 is open, allowing hot refrigerant to flow into the heating branch 16.1.

[0063] To perform the heating function and achieve water-to-heat pump operation using the cryocooler 28, refrigerant compressed by the refrigerant compressor 12 flows through the open shut-off valve A3 into the heating air conditioner 26. At the heating air conditioner 26, heat is discharged into the airflow L directed into the vehicle interior. The refrigerant then flows through the open shut-off valve A1 and branch point Ab1. The refrigerant is depressurized into the cryocooler 28 via the expansion valve AE1 to absorb residual heat from electrical and / or electronic components arranged in the coolant circuit 28.2. During this heating function, expansion valves AE3 and AE4 are closed, shut-off valve A5 is closed, and shut-off valve A2 is open. Here, refrigerant removed during water-to-heat pump operation can be drawn out from the bidirectional branch 14.1 or the primary branch 14 via shut-off valve A2 and delivered to the collector 24 via check valve R2.

[0064] To perform the heating function using the external heat exchanger 18, which acts as a heat pump evaporator, refrigerant compressed by the refrigerant compressor 12 flows through the open shut-off valve A3 into the heating air conditioner 26 to release heat to the supply airflow L. Next, the refrigerant is depressurized through the open shut-off valve A1 and via the expansion valve AE3 into the external heat exchanger 18 to absorb heat from the ambient air. Then, the refrigerant flows through the heat pump return branch 15 to the collector 24 and back to the refrigerant compressor 12. Here, expansion valves AE1, AE2, and AE4 remain closed, as does the shut-off valve A5.

[0065] An indirect triangular circuit can be implemented such that, when shut-off valve A1 is open, the refrigerant compressed by refrigerant compressor 12 is depressurized into cryogenic cooler 28 via expansion valve AE1, while no mass flow is generated on the coolant side, i.e., in coolant circuit 28.2. This means that, for example, the fluid used as coolant (such as water or a water-glycol mixture) remains on the coolant side of cryogenic cooler 28, or cryogenic cooler 28 is not actively traversed by coolant. In this circuit variation, expansion valves AE2, AE3, and AE4 remain closed.

[0066] During reheating operation, the airflow L introduced into the vehicle interior is first cooled and thus dehumidified by means of the evaporator 22. Utilizing the heat transferred to the refrigerant through evaporation and dehumidification, as well as the heat supplied to the refrigerant through the compressor 12, the airflow L can be fully or at least partially reheated by means of the reheater 26.

[0067] For this purpose, the refrigeration unit 10, especially the air conditioning unit 32, has an adjustable, especially controllable and swingable temperature valve 34 between the evaporator 22 and the heating fan 26. In the example shown, a left temperature valve 34L and a right temperature valve 34R are arranged (in... Figure 1(which is schematically shown). The temperature valves 34L, 34R can be adjusted or swung between an open position, which is referred to as the 100% position, and a closed position, which is referred to as the 0% position. Alternatively, it is equally feasible that the temperature valves 34R, 34L are后置 (the meaning of this word needs to be determined according to the context, it may be "placed behind") the heating air distributor 26.

[0068] In the 100% position, all of the supply air flow L flowing through the evaporator 22 is directed through the heating air distributor 26 and heated before the supply air flow can flow into the passenger compartment of the vehicle. In the 0% position, all of the supply air flow L flowing through the evaporator 22 flows into the passenger compartment in a bypass that bypasses the heating air distributor 26 without being heated and thus without absorbing heat.

[0069] In the x position of the temperature valves 34L, 34R, where 0% < x < 100%, the temperature valves are only partially open, so that only a partial flow of the supply air flow L flowing through the evaporator 22 is directed through the heating air distributor 26. Then, the heated partial flow can be mixed with the remaining cooled and dehumidified partial flow. The supply air flow L heated in this way is supplied to the passenger compartment of the vehicle. Exemplarily, the 50% position means that the temperature valves 34R, 34L are only half open, that is, 50% open.

[0070] The refrigeration device 10 has a sensor device 36 in the secondary branch 16 downstream of the secondary branch valve A3 and upstream of the heating air distributor 26, which is arranged to detect a hot gas temperature value representing the temperature of the gaseous refrigerant upstream of the heating air distributor 26. Here, the hot gas temperature value can be measured or detected directly, or can also be estimated indirectly by means of other system parameters. For example, it is conceivable to determine the pressure in the secondary branch 16 with the aid of the sensor device 36 and thereby obtain the hot gas temperature value. The sensor device 36 can be, for example, a pure temperature sensor or a combined temperature / pressure sensor.

[0071] When performing a heating function by means of the cryocooler 28 to achieve water - heat pump operation, the method proposed here is based on the circuit connection of the refrigeration device 10 described above. In this circuit connection, the refrigerant starts from the refrigerant compressor 12 and enters the secondary branch 16 and flows to the heating air distributor 26 (another heat exchanger). The heating air distributor 26 serves as a heat source for heating the air L that is then supplied to the interior space of the motor vehicle. Then, the refrigerant flows through the open shut-off valve A1 and the open expansion valve AE1 to the cryocooler 28 (the third heat exchanger). Then, before the refrigerant reaches the refrigerant compressor 12 again, the refrigerant is guided to the refrigerant accumulator 24 on the low-pressure side. In the heat pump operation considered here, the expansion valve AE2 is closed.

[0072] As mentioned above, the refrigerant is depressurized into the cryogenic cooler 28 to absorb residual heat from electrical and / or electronic components arranged in the coolant circuit 28.2. Here, the coolant, especially a water-glycol mixture or cooling water, serves as a heat source to heat the refrigerant, particularly to cause the refrigerant to evaporate.

[0073] It has been shown that due to the inefficiency of the electrical and / or electronic components used in motor vehicles, especially during heated operation, sufficient waste heat is not always dissipated to the coolant or cooling water, thus the coolant or cooling water is overcooled in the cryocooler 28.

[0074] To address the overcooling of the coolant, there are different feasible options for the operation of the refrigeration equipment 10, which will be discussed below.

[0075] According to the design scheme of the method proposed here, the previously closed expansion valve AE3 can be opened at least partially or gradually, so that a portion of the refrigerant mass flow is directed through the external heat exchanger 18, which then functions as an air heat pump-evaporator. In other words, a portion of the refrigerant mass flow passes through the cryocooler 28 and, in terms of flow technology, flows in parallel with the cryocooler through the external heat exchanger 18. If the external heat exchanger 18 is activated, the shut-off valve A2 opens, allowing the refrigerant to flow to the refrigerant collector 24 on the low-pressure side. Here, the primary branch valve A4 closes. These two portions of the refrigerant mass flow merge again into a total mass flow on the low-pressure side in the region of the branch point Ab4.

[0076] Instead of the two separate mass flows through the cryocooler 28 and the external heat exchanger 18, the step of the total mass flow through the external heat exchanger 18 can be selected, and thus the heating of the air flow L is performed solely by the operation of the air heat pump. In this way, the temperature level in the coolant flow can also be regenerated, since there is no longer any heat absorption on the refrigeration circuit side.

[0077] At least one temperature sensor T6 is arranged in the coolant circuit 28.2 to detect the temperature of the coolant. In addition to the cryogenic cooler 28, which is a water heat pump evaporator, the connection or operation of the external heat exchanger 18, which is an air heat pump evaporator, depends particularly on the coolant temperature or cooling water temperature detected at the temperature sensor T6.

[0078] The refrigeration device 10 may also have at least one electric heating element 40, which is configured to heat the refrigerant as needed. Figure 1 The illustrations exemplarily show electric heating elements 40 at different locations in the refrigeration device 10 or refrigerant circuit 11, wherein it is not mandatory to actually implement multiple or all of the shown heating elements 40.

[0079] As from Figure 1As can be seen, the electric heating element 40 can be disposed in the section between the refrigerant compressor 12 and the heater / air conditioner 26, for example, on the high-pressure side upstream of the heater / air conditioner 26. Alternatively, the heating element 40 can be disposed downstream of the heater / air conditioner 26, but upstream of the cryogenic cooler 28. Furthermore, it is also feasible to dispose of the heating element 40 upstream of the refrigerant compressor 12. It is also conceivable that the heating element 40 is directly distributed to the refrigerant compressor 12, or that the heating element 40 is disposed within or at the refrigerant compressor.

[0080] In the method presented here, the heating element 40 can be activated or deactivated under specific conditions, which will be described in more detail below.

[0081] The refrigeration unit 10 may also have a bypass section 42 that branches off downstream of the heater 26 (Ab6) and terminates upstream of the refrigerant compressor 12 on the low-pressure side (Ab3 or Ab7). This bypass section 42 can bypass the cryotherm 28 and the external heat exchanger 18 as needed.

[0082] To allow at least a portion of the refrigerant mass flow to be directed through bypass section 42 or to block bypass section 42, an expansion valve AE5 is provided in bypass section 42. Expansion valve AE5 can be adjusted to an open or closed state as needed to allow or prevent the desired refrigerant mass flow through bypass section 42.

[0083] If the bypass section 42 with expansion valve AE5 is provided in the refrigeration equipment 10, the suction section 44 (between Ab3 and Ab8) can be replaced by the shut-off valve A5. This is because, when the secondary branch is not working (during cooling or AC operation when the secondary branch valve A3 is closed), refrigerant can also be drawn from the secondary branch 16 by means of the bypass section 42.

[0084] According to Figure 2 Method 500, as shown herein, transitions from operation of the refrigeration unit 10 to heating or heat pump operation (S502) after startup (S501), at a time not specified in detail here. Typically, the transition to S502 may be related to a measured external temperature or a given heating requirement. For example, operation according to S502 may be started / set when the temperature is below 10°C, especially 5°C or lower. The following description of method 500 begins with the wiring connection described above, in which the total mass flow of refrigerant from the refrigerant compressor 12 through the heater 26 to the cryocooler 28 (water heat pump) and circulates back to the refrigerant compressor 12 through the refrigerant collector 24.

[0085] Here, according to step S503, the expansion valve AE1 is adjusted to the appropriate position, indicated by two upward and downward arrows. During the heating or heat pump operation considered here, the temperature of the coolant, more precisely the cooling water, in the coolant circuit 28.2 is periodically detected, for example by means of the temperature sensor T6.

[0086] Figure 2 The methods and steps described below can also be considered. Figure 3 To better understand this, in the context of a diagram, Figure 3 The limits for the coolant temperature Tkw described are qualitatively shown in the text.

[0087] According to step S504, check whether the coolant or cooling water temperature Tkw is greater than or equal to the upper temperature limit Tgo. If so (J), the total mass flow of refrigerant continues to be directed through the cryocooler 28, accompanied by one or more appropriately adjusted positions of the expansion valve AE1 (S503).

[0088] If the coolant temperature Tkw is lower than the upper temperature limit Tgo, then in step S505, it is checked whether the coolant temperature Tkw is greater than or equal to the lower temperature limit Tgu. If the detected coolant temperature Tkw is greater than the lower temperature limit Tgu, then in step S506, the difference Tdkw between the coolant temperature Tkw and the lower temperature limit is calculated. According to step S507, it is checked whether this difference Tdkw is lower than the threshold Tskw, that is, to check how close the coolant temperature Tkw is to the lower limit Tgu. The threshold Tskw can be, for example, 2K.

[0089] If the threshold Tskw is reached or fallen below, then according to step S508, the expansion valve AE3 assigned to the external heat exchanger 18 is opened. This directs a portion of the refrigerant mass flow through the external heat exchanger 18. Relatedly, according to step S509, the expansion valve AE1 assigned to the cryostat is partially closed, so that only a portion of the refrigerant mass flow is also directed through the cryostat 28. Subsequent steps S510 and S511 indicate that expansion valves AE1 and AE3 are switched to an regulated state to direct the desired portion of the mass flow through the cryostat 28 or the external heat exchanger 18. Regarding the control or regulation of expansion valve AE3, a criterion that can be considered is that AE3 is set such that the refrigerant temperature at the inlet into the external heat exchanger 18 reaches at most the ambient temperature level, or slightly below this ambient temperature, for example, 1K to 2K lower than the ambient temperature.

[0090] Based on steps S504 to S507, the necessity of combining the external heat exchanger 18 as an air heat pump evaporator is checked. If the refrigerant temperature Tkw reaches the upper temperature limit Tgo (S504), it is checked in step S512 whether the expansion valve AE3 is still open. If the expansion valve AE3 is still open, it is closed in step S513. Then, according to step S503, the expansion valve AE1 is adjusted to a suitable position so that the total mass flow of refrigerant is redirected through the cryocooler 28 again.

[0091] If the refrigerant temperature Tkw has not reached the upper limit Tgo, but the difference Tdkw is greater than the threshold Tsw (S507), then in step S514, it is checked whether the expansion valve AE3 is closed. If the expansion valve AE3 is closed, then in the case where the difference Tdkw is greater than the threshold Tskw but the upper limit Tgo has not been reached, the process branches to step S503, and the total mass flow of refrigerant continues to be directed through the cryocooler 28 by adjusting the expansion valve AE1 accordingly (S503). If the expansion valve AE3 is open, then in the case where the difference Tdkw is greater than the threshold Tskw but the upper limit Tgo has not been reached, the operation of both heat pumps (cryocooler 28 and external heat exchanger 18) is maintained, and the process branches to steps S510 and S511.

[0092] If the coolant temperature Tkw is lower than the lower limit Tgu (S505), which should be avoided as much as possible by means of the method described here, the expansion valve AE1 can be closed according to step S515, and the water heat pump operation of the cryocooler 28 can be terminated (S516). Here, the transition to another operation of the refrigeration unit 10 is then made, such as pure triangular process or air heat pump operation, but this will not be discussed in detail here.

[0093] refer to Figure 2 The operating method 500 is described, in which, for air heat pump operation, if the temperature Tkw of the coolant in the cryocooler 28 (third heat exchanger) is too low to continue to effectively guarantee the water-heat pump function, the external heat exchanger 18 is used as the (air) heat pump evaporator.

[0094] Figure 4 The schematic simplified diagram illustrates alternative measures or method steps that allow the refrigerant in the refrigerant circuit to be heated as the coolant temperature Tkw at the cryogenic cooler 28 decreases, so as to achieve sufficient heating power, in particular, for heating the air in the interior space.

[0095] Regarding steps S501 to S507, please refer to the above text. Figure 2 and Figure 3 The explanation also applies to Figure 4 .

[0096] If the threshold Tskw is reached or fallen according to the check in step S507, then at least one electric heating element 40 is activated according to step S608. Figure 1 This is indicated by the heating element symbol and "=1". (As already referenced...) Figure 1 As described, the heating element 40 can be arranged upstream or downstream of the third heat exchanger or cryogenic cooler 28.

[0097] If at least one heating element 40 is activated according to step S608, then according to step S609, the expansion valve AE1 assigned to the cryocooler 28 can be at least partially closed or adjusted to a suitable open position (S611). According to step S610, the at least one heating element 40 can also be adjusted to an adjusted activation state.

[0098] If the coolant temperature Tkw has not reached the upper limit Tgo, but the difference Tdkw is greater than the threshold Tsw (S507), then in step S614, it is checked whether the heating element 40 is not working. If the heating element is not working, and the difference Tdkw is greater than the threshold Tskw but the upper limit Tgo has not been reached, the process branches to step S502, and the total mass flow of refrigerant continues to be guided through the cryocooler 28 by adjusting the expansion valve AE1 accordingly (S503). If the heating element 40 is working, and the difference Tdkw is greater than the threshold Tskw but the upper limit Tgo has not been reached, the operation of the heat pump (cryocooler 28) and the heating element 40 is maintained, and the process branches to steps S610 and S611.

[0099] Based on steps S504 to S507, the necessity of activating at least one heating element 40 is checked. If the coolant temperature Tkw reaches the upper temperature limit Tgo (S504), it is checked in step S612 whether the heating element 40 is (still) activated. If it is still activated, the heating element 40 is deactivated in step S613. Then, according to step S503, the expansion valve AE1 is adjusted to a suitable position so that the total mass flow of refrigerant is redirected through the cryocooler 28 again.

[0100] Figure 5 A simplified schematic diagram illustrates alternative measures or method steps that allow the refrigerant in the refrigerant circuit to be heated as the coolant temperature Tkw at the cryocooler 28 decreases, so as to achieve sufficient heating power, in particular, for heating the air supplied to the interior space.

[0101] Regarding steps S501 to S507, please refer to the following... Figure 2 and Figure 3 The above explanation also applies to Figure 5 .

[0102] If the threshold Tskw is reached or fallen below, according to step S708, the expansion valve AE5 assigned to the bypass section 42 is opened. This directs a portion of the refrigerant mass flow through the bypass section 42. In connection with this, according to step S709, the expansion valve AE1 assigned to the cryostat is partially closed, such that only a portion of the refrigerant mass flow is still directed through the cryostat 28. Subsequent steps S710 and S711 indicate that expansion valves AE1 and AE5 are switched to an regulated state to direct the desired portion of the mass flow through either the cryostat 28 or the bypass section 42.

[0103] Based on steps S504 to S507, the necessity of connecting to the bypass section 42 is checked. If the coolant temperature Tkw reaches the upper temperature limit Tgo (S504), then in step S712, it is checked whether the expansion valve AE5 is (still) open. If it is still open, then in step S713, the expansion valve is gradually closed. Next, according to step S503, the expansion valve AE1 is adjusted to a suitable position so that the total mass flow of refrigerant is redirected through the cryocooler 28 again.

[0104] If the refrigerant temperature Tkw has not reached the upper limit Tgo, but the difference Tdkw is greater than the threshold Tsw (S507), then in step S714, it is checked whether the expansion valve AE5 is closed. If it is closed, then in the case where the difference Tdkw is greater than the threshold Tskw but the upper limit Tgo has not been reached, the process branches to step S503, and the total mass flow of refrigerant continues to be guided through the cryocooler 28 by adjusting the expansion valve AE1 accordingly (S503). If the expansion valve AE5 is open, then in the case where the difference Tdkw is greater than the threshold Tskw but the upper limit Tgo has not been reached, the operation of both heat pumps (the cryocooler 28 and the triangular process through the expansion mechanism AE5) is maintained, and the process branches to steps S710 and S711.

[0105] If the coolant temperature Tkw is lower than the lower limit Tgu (S505), which should be avoided as much as possible by means of the method described here, then according to step S515, the expansion valve AE1 can be closed and the water heat pump operation of the cryocooler 28 can be terminated (S516). Here, it then switches to another operation of the refrigeration equipment 10, such as a pure triangular process or air heat pump operation, which will not be discussed in detail here.

[0106] Method 500 described above Figures 2 to 5The temperature limits Tgu and Tgo used or considered during this period can be given based on the current ambient temperature and / or relative humidity. Therefore, it is conceivable to store or store temperature limits Tgu and Tgo suitable for the corresponding ambient temperature and / or relative humidity values, which can then be used in this method. Another criterion for determining the temperature limits Tgu and Tgo can be the temperature difference between the ambient temperature and the refrigerant temperature.

[0107] It should be noted that, for reference Figures 2 to 5 The methods and steps described can be combined as needed, even if they are not shown in a single (compound) diagram for clear reasons. For example, it is conceivable to combine... Figure 2 The steps of the method shown (combined with an external heat exchanger as an air heat pump) involve activating / deactivating the heating element 40. Figure 4 Furthermore, for example, the activation / deactivation of the heating element 40 can be combined with the incorporation of the bypass section 42.

Claims

1. A method (500) for operating a refrigeration device (10) with heat pump function for a motor vehicle, wherein, The refrigeration equipment (10) includes: A refrigerant compressor (12) that can be connected to the primary branch (14) and the secondary branch (16); An external heat exchanger (18) that acts directly or indirectly is arranged in the primary branch (14); Evaporator (22), which is arranged in the primary branch (14); At least one additional heat exchanger serving as a heat source is arranged in the secondary branch (16); A primary branch valve (A4) is arranged between the refrigerant compressor (12) and the external heat exchanger (18); A secondary branch valve (A3) is arranged between the refrigerant compressor (12) and the other heat exchanger, which serves as a heat source; As a third heat exchanger that functions directly or indirectly as a water heat pump (28); The method (500) includes the following steps: Set (S502) heat pump operation, in which refrigerant is guided from the refrigerant compressor (12) to the secondary branch (16); The expansion valve (AE1) allocated to the third heat exchanger (28) is adjusted (S503) so that the total mass flow of the refrigerant flows through the third heat exchanger (28) and is evaporated in the third heat exchanger (28) by the residual heat of the coolant circulating in the third heat exchanger (28); Detect (S504) the temperature (Tkw) of the coolant in or at the third heat exchanger (28); If the temperature of the coolant (Tkw) is greater than the upper limit temperature (Tgo), then the total mass flow of the refrigerant is directed through the third heat exchanger (28). If the temperature (Tkw) of the coolant is lower than the upper limit temperature (Tgo), then based on the difference (Tdkw) between the temperature of the coolant in the third heat exchanger (28) and the lower limit temperature (Tgu), the expansion valve (AE3) allocated to the external heat exchanger (18) is adjusted (S508, S510) so that a portion of the refrigerant mass flow through the external heat exchanger (18) which operates as an air heat pump. At the same time, the expansion valve (AE1) allocated to the third heat exchanger (28) is adjusted (S509, S511) so that another portion of the refrigerant mass flow continues to flow through the third heat exchanger (28).

2. The method (500) according to claim 1, characterized in that, The other heat exchanger is a heated air conditioner (26).

3. The method (500) according to claim 1, characterized in that, The third heat exchanger (28) is a cryogenic cooler.

4. The method (500) according to any one of claims 1 to 3, wherein, When the difference (Tdkw) is 2K or less, the expansion valve (AE3) assigned to the external heat exchanger (18) is opened at least partially (S507).

5. The method (500) according to any one of claims 1 to 3, wherein, Maintain a portion of the refrigerant mass flow through the external heat exchanger (18) until the refrigerant temperature (Tkw) reaches or exceeds the upper limit temperature (Tgo) (S504, S512, S513).

6. The method (500) according to any one of claims 1 to 3, wherein, Select the upper limit temperature (Tgo) and lower limit temperature (Tgu) based on the detected ambient temperature.

7. The method (500) according to any one of claims 1 to 3, wherein, The upper limit temperature (Tgo) and lower limit temperature (Tgu) are selected based on the detected ambient relative humidity.

8. The method (500) according to any one of claims 1 to 3, wherein, The upper limit temperature (Tgo) and the lower limit temperature (Tgu) are selected based on the possible temperature difference between the ambient temperature and the refrigerant temperature in the external heat exchanger (18) during the operation of the refrigeration equipment.

9. The method (500) according to claim 8, wherein, The expansion valve (AE3) assigned to the external heat exchanger (18) is adjusted such that the refrigerant temperature at the inlet of the external heat exchanger (18) is less than or equal to the ambient temperature.

10. The method (500) according to claim 9, characterized in that, The expansion valve (AE3) assigned to the external heat exchanger (18) is adjusted such that the refrigerant temperature at the inlet of the external heat exchanger (18) is 1 to 5 openings lower than the ambient temperature.

11. The method (500) according to any one of claims 1 to 3, wherein, When the difference is greater than 5, the expansion valve (AE3) assigned to the external heat exchanger (18) is closed.

12. The method according to any one of claims 1 to 3, wherein, When the difference (Tdkw) is 2 on or lower, at least one electric heating element (40) is activated (S608) to heat the refrigerant upstream or downstream of the third heat exchanger (28).

13. The method according to claim 12, wherein, When the difference is greater than 5, the electric heating element (40) is deactivated.

14. The method according to any one of claims 1 to 3, wherein, When the difference (Tdkw) is 2 or lower, at least a portion of the refrigerant mass flow is directed downstream of the additional heat exchanger to the low-pressure side, bypassing the third heat exchanger and / or the external heat exchanger (S708).

15. The method according to claim 14, wherein, When the difference is greater than 5, the refrigerant mass flow will no longer bypass the third heat exchanger and / or the external heat exchanger.

16. A refrigeration device (10) with heat pump function for motor vehicles, wherein, The refrigeration equipment (10) includes: A refrigerant compressor (12) that can be connected to the primary branch (14) and the secondary branch (16); An external heat exchanger (18) that acts directly or indirectly is arranged in the primary branch (14); Evaporator (22), which is arranged in the primary branch (14); At least one additional heat exchanger serving as a heat source is arranged in the secondary branch (16); A primary branch valve (A4) is arranged between the refrigerant compressor (12) and the external heat exchanger (18); A secondary branch valve (A3) is arranged between the refrigerant compressor (12) and the other heat exchanger, which serves as a heat source; As a third heat exchanger that functions directly or indirectly as a water heat pump (28); Its features are, The refrigeration device (10) has at least one temperature sensor (T6) configured to detect the coolant temperature (Tkw) in the third heat exchanger (28). The refrigeration device (10) is configured to adjust the expansion valve (AE1) allocated to the third heat exchanger (28) and the expansion valve (AE3) allocated to the external heat exchanger (18) based on the detected coolant temperature (Tkw). Specifically, if the coolant temperature (Tkw) is greater than the upper limit temperature (Tgo), the total mass flow of the refrigerant is directed through the third heat exchanger (28); if the coolant temperature (Tkw) is greater than the upper limit temperature (Tgo), the total mass flow of the refrigerant is directed through the third heat exchanger (28); if the coolant temperature (Tkw) is greater than the upper limit temperature (Tgo), the total mass flow of the refrigerant is directed through the third heat exchanger (28). If the temperature (Tkw) is lower than the upper limit temperature (Tgo), then based on the difference (Tdkw) between the temperature of the refrigerant in the third heat exchanger (28) and the lower limit temperature (Tgu), the expansion valve (AE3) allocated to the external heat exchanger (18) is adjusted (S508, S510) so that a portion of the refrigerant mass flow through the external heat exchanger (18) which operates as an air heat pump. At the same time, the expansion valve (AE1) allocated to the third heat exchanger (28) is adjusted (S509, S511) so that another portion of the refrigerant mass flow continues to flow through the third heat exchanger (28).

17. The refrigeration equipment (10) according to claim 16, characterized in that, The other heat exchanger is a heated air conditioner (26).

18. The refrigeration equipment (10) according to claim 16, characterized in that, The third heat exchanger (28) is a cryogenic cooler.

19. The refrigeration device (10) according to any one of claims 16 to 18, characterized in that, The refrigeration equipment has at least one bypass section (42) branching off downstream of the additional heat exchanger (26), which extends on the low-pressure side to the upstream (Ab3, Ab7) of the refrigerant compressor (12), bypassing the third heat exchanger (28) and the external heat exchanger (18).

20. The refrigeration equipment (10) according to claim 19, characterized in that, A bypass expansion valve (AE5) is arranged in the bypass section (42).

21. The refrigeration equipment (10) according to claim 19, characterized in that, The bypass section (42) leads upstream of the refrigerant collector (24) located on the low-pressure side.

22. The refrigeration device (10) according to any one of claims 16 to 18, characterized in that, The refrigeration equipment has at least one electric heating element (40) which is assigned to the refrigerant circuit and is configured to heat the refrigerant as needed.

23. A motor vehicle having a refrigeration device (10) according to any one of claims 16 to 22.

24. The motor vehicle according to claim 23, characterized in that, The motor vehicle is a motor vehicle that operates at least partially on ground power.

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