Refrigeration circuit and method for operating a refrigeration circuit

Abstract

The present disclosure relates to a refrigeration circuit (100A, 100B, 100C) comprising: - at least one refrigerant pump (110) which is designed to compress a refrigerant and to circulate the refrigerant in the refrigeration circuit (100A, 100B, 100C), a temperature of the refrigerant after compression being higher than a critical temperature of the refrigerant; - at least one precooler (120) which is arranged downstream of the at least one refrigerant pump (110) in the refrigeration circuit (100A, 100B, 100C) and is designed to precool the refrigerant compressed by the at least one refrigerant pump (110); - at least one main cooler (130) which is arranged downstream of the at least one precooler (120) in the refrigeration circuit (100A, 100B, 100C) and is designed to further cool the refrigerant precooled by the at least one precooler (120); and - at least one main heat exchanger (14A, 140B) which is arranged downstream of the at least one main cooler (130) in the refrigeration circuit (100A, 100B, 100C).

Description

[0001] Refrigeration cycle and methods for operating a refrigeration cycle

[0002] The present disclosure relates to a refrigeration cycle and a method for operating a refrigeration cycle. The present disclosure relates in particular to a refrigeration cycle for carbon dioxide (CO2) or R744.

[0003] State of the art

[0004] Conventional refrigeration systems often use refrigerants containing PFAS, i.e., per- and polyfluorinated substances. The use of PFAS-containing refrigerants, for example in vehicles, raises a number of environmental, health, and technical concerns. For instance, PFAS are extremely persistent, meaning they do not readily break down in the environment. Once released, they can remain in nature for very long periods, leading to long-term environmental pollution.

[0005] Due to the known risks, many countries have begun to strictly regulate or even ban the use of PFAS-containing products, including refrigerants. This can lead to legal challenges and higher costs for vehicle manufacturers, who will have to switch to alternative refrigerants.

[0006] Disclosure of the invention

[0007] It is an objective of the present disclosure to specify a refrigeration cycle and a method for operating a refrigeration cycle that enable efficient operation with alternative refrigerants, such as carbon dioxide. In particular, it is an objective of the present disclosure to provide a simple cycle architecture for carbon dioxide or R744.

[0008] This problem is solved by the subject matter of the independent claims. Advantageous embodiments are specified in the dependent claims. According to an independent aspect of the present disclosure, a refrigeration circuit, in particular for a cooling and / or heating system of a vehicle, is specified.The refrigeration cycle comprises at least one refrigerant pump configured to compress a refrigerant and circulate it within the cycle, wherein the temperature of the refrigerant after compression is higher than a critical temperature of the refrigerant; at least one precooler arranged downstream of the at least one refrigerant pump in the refrigeration cycle and configured to precool the refrigerant compressed by the at least one refrigerant pump; at least one main cooler arranged downstream of the at least one precooler in the refrigeration cycle and configured to further cool the refrigerant precooled by the at least one precooler; and at least one main heat exchanger arranged downstream of the at least one main cooler in the refrigeration cycle.

[0009] According to the invention, a refrigeration circuit architecture is provided that enables the use of a natural refrigerant, such as carbon dioxide or R744. For this purpose, the refrigeration circuit includes a pre-cooler (e.g., a water gas cooler) which is connected as a separate component downstream of the refrigerant pump, so that the refrigerant, which is heated considerably by compression, is pre-cooled immediately after leaving the refrigerant pump. This allows the refrigerant to be fed into the rest of the refrigeration circuit without requiring special adaptations or modifications to components such as the main cooler (e.g., a hot gas cooler installed at the front of a vehicle) or main heat exchangers (e.g., evaporator, chiller, etc.) to cope with the high temperatures of the compressed refrigerant. As a result, a simple circuit architecture for alternative refrigerants, such as carbon dioxide or R744, can be implemented.R744 will be provided.

[0010] The refrigerant used in the embodiments of the present disclosure is a substance whose temperature, after compression by the refrigerant pump, is higher than a critical temperature of the refrigerant. The critical temperature is the highest temperature at which a substance can be converted into a liquid phase by applying pressure. Above this temperature, the substance exists only as a supercritical fluid, in which the distinction between liquid and gaseous states becomes blurred.

[0011] An example of such a refrigerant is carbon dioxide, also known as R744, which has a critical temperature of only 31°C. For an efficient cycle, carbon dioxide can be compressed to up to 130 bar, raising the temperature to up to 160°C, which is significantly above the critical temperature of 31°C. This presents new challenges for the refrigeration cycle, particularly regarding the high temperatures after compression and handling the refrigerant in its supercritical state. Such challenges do not arise with a conventional refrigerant like RI 34a (tetrafluoroethane), as it has a much higher critical temperature of 101°C and its cycle typically operates below this temperature.

[0012] At least one refrigerant pump is installed to circulate the refrigerant within the refrigeration cycle. This pump also increases the pressure and therefore the temperature of the refrigerant. The refrigerant pump can thus also be referred to as a "compressor".

[0013] Preferably, the at least one precooler comprises or is a water gas cooler. The water gas cooler is a component that serves to cool the refrigerant immediately after compression by heat exchange with water. In particular, the hot refrigerant is cooled by water flowing through the water gas cooler. The water absorbs the heat energy of the refrigerant, thereby cooling it.

[0014] The precooler is a separate component located downstream of the refrigerant pump. In other words, the precooler is not integrated into the refrigerant pump. Separating the precooler from the refrigerant pump offers flexibility in system design, simplifies maintenance and repair, potentially reduces costs, and improves thermal efficiency. For example, the precooler's independent positioning allows it to operate under optimal cooling conditions without being constrained by the refrigerant pump's operating conditions.

[0015] Preferably, the at least one main cooler includes a heating gas cooler. The heating gas cooler is a component that serves to cool the refrigerant by heat exchange with an external medium. The external medium can be, for example, air for a vehicle interior.

[0016] Preferably, at least one main cooler, in particular the hot gas cooler, is designed for interior heating.

[0017] Preferably, the at least one main cooler, in particular the hot gas cooler, can be installed in a front area of ​​a vehicle. For example, a hot gas cooler of a conventional R134a system can be incorporated into the refrigeration circuit of the present disclosure without modification, since the pre-cooling of the compressed refrigerant prevents damage from excessively high refrigerant temperatures.

[0018] Preferably, the refrigeration cycle includes at least one air-cooled gas cooler (ACG) arranged downstream of the at least one main cooler in the cycle. The air cooler cools the refrigerant by passing it through a heat exchanger surrounded by air. For example, ambient air is passed over a surface of the heat exchanger, either by natural convection or by fans. The heat from the refrigerant is transferred to the air, and the refrigerant cools down.

[0019] Preferably, the refrigeration circuit comprises at least one first expansion valve configured to expand the refrigerant into the at least one air cooler. For example, the at least one first expansion valve can be arranged between the at least one main cooler and the at least one air cooler in the refrigeration circuit to expand the refrigerant into the at least one air cooler.

[0020] Preferably, at least one first expansion valve is selected from the group comprising, or consisting of, a thermostatic expansion valve, an electronic expansion valve, a capillary tube and combinations thereof.

[0021] The thermostatic expansion valve automatically adjusts the refrigerant flow rate based on the temperature at the outlet of at least one evaporator. It uses, for example, a sensor line that measures the refrigerant's superheat and adjusts the valve cross-section accordingly. The electronic expansion valve is electronically controlled and allows for more precise regulation of the refrigerant flow rate. The capillary tube does not offer active control but relies on a fixed flow rate due to the tube's resistance.

[0022] Preferably, the refrigeration cycle includes at least one internal heat exchanger (IWT). An internal heat exchanger (IWT) is a component in the refrigeration cycle that exchanges heat between two flows of the refrigerant within the same system.

[0023] Preferably, the at least one internal heat exchanger is connected between an outlet of the at least one main cooler (or an outlet of the at least one air cooler) and an inlet of the at least one refrigerant pump. With this connection, the at least one internal heat exchanger can increase the efficiency of the refrigeration cycle by further increasing the enthalpy of the refrigerant before it enters the at least one refrigerant pump and simultaneously further reducing the enthalpy of the refrigerant before it enters the at least one main heat exchanger (e.g., an evaporator).

[0024] Preferably, the at least one main heat exchanger includes at least one evaporator. The at least one evaporator (also called a "condenser") absorbs heat from a medium to be cooled, such as air. This heat absorption causes the refrigerant to evaporate, i.e., to change from a liquid to a gaseous state.

[0025] Preferably, at least one evaporator is designed for interior cooling.

[0026] Preferably, the refrigeration circuit comprises at least one second expansion valve configured to expand the refrigerant into the at least one evaporator. For example, the at least one second expansion valve can be arranged between an outlet of the at least one internal heat exchanger and an inlet of the at least one evaporator in the refrigeration circuit to expand the refrigerant into the at least one evaporator.

[0027] Preferably, at least one second expansion valve is selected from the group comprising, or consisting of, a thermostatic expansion valve, an electronic expansion valve, a capillary tube and combinations thereof.

[0028] Preferably, the refrigeration circuit includes at least one refrigerant receiver (accumulator). This receiver serves as a storage container for the refrigerant and ensures that a sufficient quantity of refrigerant is always present in the system. Furthermore, the receiver can absorb excess refrigerant and release it back into the refrigeration circuit as needed.

[0029] Preferably, the at least one refrigerant collector is connected between an outlet of the at least one main heat exchanger and an inlet of the at least one refrigerant pump (or an inlet of the at least one internal heat exchanger).

[0030] Preferably, the at least one main heat exchanger comprises at least one additional evaporator, such as a chiller. Preferably, the at least one additional evaporator is configured for cooling a drive system and / or a drive energy storage system. The at least one additional evaporator absorbs heat, for example, from a drive system and / or a drive energy storage system of the vehicle in order to cool the drive system and / or the drive energy storage system. A drive energy storage system, or high-voltage storage system, in a hybrid or electric vehicle is an energy storage system that stores electrical energy in the form of high-voltage direct current. This stored energy is used to drive at least one electric motor of the vehicle. Typically, these drive energy storage systems are composed of lithium-ion cells or modules configured in a battery pack.

[0031] Preferably, the refrigeration circuit includes at least one third expansion valve configured to expand the refrigerant into the at least one further evaporator. For example, the at least one third expansion valve can be arranged between an outlet of the at least one internal heat exchanger and an inlet of the at least one further evaporator in the refrigeration circuit to expand the refrigerant into the at least one further evaporator.

[0032] Preferably, at least one third expansion valve is selected from the group comprising, or consisting of, a thermostatic expansion valve, an electronic expansion valve, a capillary tube and combinations thereof.

[0033] Preferably, the refrigeration circuit comprises at least one bypass connecting an outlet of the at least one main cooler and an inlet of the at least one main heat exchanger (or of the at least one second expansion valve).

[0034] Preferably, the refrigeration circuit includes at least one fourth expansion valve arranged in the bypass to selectively open and close the bypass. Preferably, the at least one fourth expansion valve is selected from the group consisting of, or comprising, a thermostatic expansion valve, an electronic expansion valve, a capillary tube, and combinations thereof.

[0035] According to a further independent aspect of the present disclosure, a cooling and / or heating system, in particular for a vehicle, is specified. The cooling and / or heating system comprises at least one refrigeration circuit according to the embodiments of the present disclosure.

[0036] Preferably, the cooling and / or heating system is an indirect cooling and / or heating system with multiple (separate) circuits. In an indirect cooling and / or heating system, heat is not transferred directly to the environment, but via an intermediate medium, usually a secondary coolant. The indirect cooling and / or heating system typically consists of two separate circuits, generally referred to as the primary circuit and the secondary circuit. A refrigerant circulates in the primary circuit. The secondary circuit contains a coolant that exchanges heat with the primary circuit and is transported to the locations in the vehicle where cooling is required—for example, to the battery cooling system in electric vehicles or to other components that need to be cooled.

[0037] Preferably, the refrigeration cycle described in this document forms the primary cycle of the indirect cooling and / or heating system.

[0038] According to another independent aspect of the present disclosure, a vehicle, in particular a motor vehicle, is specified. The vehicle comprises the cooling and / or heating system according to the embodiments of the present disclosure.

[0039] Preferably, the cooling and / or heating system is designed for air conditioning a vehicle interior and / or thermal management of a vehicle drive system (e.g., a drive energy storage system). The term "vehicle" includes cars, trucks, vans, buses, motorhomes, motorcycles, etc., used for the transport of persons, goods, etc. In particular, the term includes motor vehicles for passenger transport.

[0040] According to another independent aspect of the present disclosure, a method for operating a refrigeration cycle is specified.The method comprises providing a refrigeration circuit with at least one refrigerant pump configured to compress a refrigerant and circulate it within the circuit, wherein the refrigerant temperature after compression is higher than a critical temperature of the refrigerant; at least one precooler arranged downstream of the at least one refrigerant pump in the refrigeration circuit and configured to precool the refrigerant compressed by the at least one refrigerant pump; at least one main cooler arranged downstream of the at least one precooler in the refrigeration circuit and configured to further cool the refrigerant precooled by the at least one precooler; and at least one main heat exchanger arranged downstream of the at least one main cooler in the refrigeration circuit; and operating the at least one refrigerant pump to circulate the refrigerant within the refrigeration circuit.

[0041] The process can implement the aspects of the refrigeration cycle described in this document.

[0042] Brief description of the drawings

[0043] Examples of the manifestation of the revelation are shown in the figures and are described in more detail below. They show:

[0044] Figure 1 schematically shows a log pH diagram for a refrigerant according to embodiments of the present disclosure, Figure 2 schematically shows a refrigeration cycle according to embodiments of the present disclosure,

[0045] Figure 3 schematically shows a refrigeration circuit according to further embodiments of the present disclosure,

[0046] Figure 4 schematically shows a refrigeration cycle according to further embodiments of the present disclosure, and

[0047] Figure 5 shows a flowchart of a method for operating a refrigeration cycle according to embodiments of the present disclosure.

[0048] Implementations of the revelation

[0049] Unless otherwise noted, the same reference symbols are used for identical and equivalent elements in the following.

[0050] Figure 1 schematically shows a log ph diagram for a refrigerant according to embodiments of the present disclosure.

[0051] The diagram shown here illustrates the typical principle of a counterclockwise cycle using a log pH diagram (pressure-enthalpy diagram). This cycle consists of four main phases, defined by the essential components of the system:

[0052] 1. Compressor: In this step of the cycle, the refrigerant is compressed adiabatically (without heat exchange) in the compressor. This leads to an increase in the pressure, enthalpy, and temperature of the refrigerant. In the diagram, this process is represented as an upward shift. The refrigerant used in the embodiments of the present disclosure is a substance whose temperature after compression is higher than a critical temperature (TC) of the refrigerant. An example of such a refrigerant is carbon dioxide, which has a critical temperature (TC) of 31 °C. For an efficient cycle, the carbon dioxide can be compressed to up to 130 bar, with the temperature rising to up to 160 °C, which is significantly above the critical temperature of 31 °C.In contrast, with a conventional refrigerant such as RI 34a, which has a significantly higher critical temperature of 101°C, the cycle usually takes place below the critical temperature, i.e., RI 34a is not compressed to such an extent that the temperature rises above the critical temperature.

[0053] 2. Cooler: The compressed refrigerant is in a supercritical state, so condensation would not occur as in a cycle, e.g., with R134a. Instead, several cooling stages, such as a water-gas cooler and a hot-gas cooler, are provided to cool the compressed refrigerant. In the log pH diagram, this process is represented by a horizontal shift to the left at high pressure. Here, the pressure remains almost constant, while the enthalpy decreases.

[0054] 3. Expansion valve: After cooling, the refrigerant passes through an expansion valve. Here, its pressure drops, causing a significant decrease in the refrigerant's temperature. In the diagram, this process is represented as an almost vertical pressure drop. This step prepares the refrigerant for heat exchange in the evaporator.

[0055] 4. Evaporator and / or Chiller: Finally, the expanded refrigerant enters the evaporator and / or chiller, where, at low pressure, it absorbs heat, e.g., from a vehicle interior (evaporator) or from a powertrain (chiller), and evaporates. The enthalpy of the refrigerant increases again as it absorbs heat. In the diagram, this process is represented as a horizontal shift to the right at low pressure. The now gaseous refrigerant is then returned to the compressor, thus restarting the cycle. Figure 2 schematically shows a refrigeration cycle 100A according to embodiments of the present disclosure.

[0056] In some embodiments, the refrigeration circuit 100 A of the present disclosure can be configured for air conditioning a vehicle interior and / or thermal management of a vehicle drive system (e.g., a drive energy storage system). However, the present disclosure is not limited to this, and other areas of application and uses for the refrigeration circuit 100 A of the present disclosure are conceivable.

[0057] The refrigeration circuit 100A comprises at least one refrigerant pump 110, which is configured to compress a refrigerant and circulate it in the refrigeration circuit 100A, wherein the temperature of the refrigerant after compression is higher than a critical temperature of the refrigerant; at least one precooler 120, which is arranged downstream of the at least one refrigerant pump 110 in the refrigeration circuit and is configured to precool the refrigerant compressed by the at least one refrigerant pump 110; at least one main cooler 130, which is arranged downstream of the at least one precooler 120 in the refrigeration circuit 100A and is configured to further cool the refrigerant precooled by the at least one precooler 120; and at least one main heat exchanger 140A, which is arranged downstream of the at least one main cooler in the refrigeration circuit.

[0058] The refrigerant can be carbon dioxide, specifically R744, which has a critical temperature of only 31°C. For an efficient cycle, carbon dioxide can be compressed to up to 130 bar, raising the temperature to up to 160°C, which is significantly above the critical temperature of 31°C.

[0059] The at least one precooler 120 is a separate component located downstream of the at least one refrigerant pump 110. In other words, the at least one precooler 120 is not integrated into the at least one refrigerant pump 110. Separating the precooler and refrigerant pump offers flexibility in system design, facilitates maintenance and repair, potentially reduces costs, and improves thermal efficiency. For example, the independent positioning of the precooler allows it to operate under optimal cooling conditions without being restricted by the operating conditions of the refrigerant pump. In some embodiments, the at least one precooler 120 includes or is a water-gas cooler.

[0060] In some embodiments, the at least one main cooler 130 includes a hot gas cooler. The hot gas cooler can cool the refrigerant by heat exchange with an external medium. The external medium can be, for example, air for a vehicle interior.

[0061] At least one main radiator 130, in particular the refrigerant radiator, can be configured for interior heating. In other words, at least one main radiator 130 can extract heat from the refrigerant to heat the vehicle interior.

[0062] The at least one main cooler 130 can be installed in a front area of ​​the vehicle. For example, a hot gas cooler of a conventional R134a system can be incorporated into the refrigeration circuit 100A of the present disclosure without modifications, since no damage due to excessively high refrigerant temperature is to be expected due to the pre-cooling of the compressed refrigerant.

[0063] In some embodiments, the refrigeration circuit 100A includes at least one air cooler 150, which is arranged downstream of the at least one main cooler 130 in the refrigeration circuit 100A. The at least one air cooler 150 cools the refrigerant by passing it through a heat exchanger surrounded by air. For example, ambient air is passed over a surface of the heat exchanger, either by natural convection or by fans. In this process, the heat of the refrigerant is transferred to the surroundings, and the refrigerant cools down.

[0064] In some embodiments, the refrigeration circuit 100A comprises at least one first expansion valve 160A, which is configured to expand the refrigerant into the at least one air cooler 150. For example, the at least one first expansion valve 160A can be arranged between the at least one main cooler 130 and the at least one air cooler 150 in the refrigeration circuit 100A to expand the refrigerant into the at least one air cooler 150.

[0065] In some embodiments, the refrigeration circuit 100 A comprises at least one internal heat exchanger 170. An internal heat exchanger is a component in the refrigeration circuit that exchanges heat between two flows of the refrigerant within the same system. The at least one internal heat exchanger 170 can be connected between an outlet of the at least one air cooler 150 and an inlet of the at least one refrigerant pump 110.

[0066] In some embodiments, the at least one main heat exchanger comprises at least one evaporator 140A. The at least one evaporator 140A absorbs heat from a medium to be cooled, such as air. This heat absorption causes the refrigerant to begin to evaporate, i.e., to change from a liquid to a gaseous state.

[0067] At least one 140 A evaporator can be configured for interior cooling. In other words, at least one 140 A evaporator can extract heat from the air in the vehicle interior to cool the vehicle interior.

[0068] In some embodiments, the refrigeration circuit 100A includes at least one second expansion valve 160B, which is configured to expand the refrigerant into the at least one evaporator 140A. For example, the at least one second expansion valve 160B can be arranged between an outlet of the at least one internal heat exchanger 170 and an inlet of the at least one evaporator 140A in the refrigeration circuit 100A to expand the refrigerant into the at least one evaporator. Optionally, a first check valve 190A can be arranged between the outlet of the at least one internal heat exchanger 170 and an inlet of the at least one second expansion valve 160B.

[0069] In some embodiments, the refrigeration circuit 100A includes at least one refrigerant receiver 180. The at least one refrigerant receiver 180 serves as a storage container for the refrigerant and ensures that a sufficient quantity of refrigerant is always present in the system. In addition, the at least one refrigerant receiver 180 can absorb excess refrigerant and release it back into the refrigeration circuit as needed.

[0070] The at least one refrigerant collector 180 can be connected between an outlet of the at least one evaporator 140 A and an input of the at least one internal heat exchanger 170.

[0071] Optionally, a second check valve 190B can be arranged between the outlet of the at least one evaporator 140A and that of the at least one refrigerant collector 180.

[0072] The following are some example operating modes for the 100A refrigeration circuit.

[0073] 1. Cooling the vehicle interior

[0074] The vehicle interior can be cooled using at least one evaporator 140A. As described with reference to Figure 1, the refrigerant can absorb heat from the vehicle interior (e.g., via a corresponding secondary or coolant circuit of an indirect cooling and / or heating system), thereby increasing the enthalpy of the refrigerant. In the log pH diagram, this process is represented as a horizontal shift to the right at low pressure (point 4 to point 1). 2. Heating the vehicle interior

[0075] Heating the vehicle interior can be achieved using at least one main radiator 130. As described with reference to Figure 1, the refrigerant can release heat into the vehicle interior (e.g., via a corresponding secondary or coolant circuit of an indirect cooling and / or heating system), thereby reducing the enthalpy of the refrigerant. In the log pH diagram, this process is represented as a horizontal shift to the left at high pressure (point 2 to point 3).

[0076] However, it is also conceivable to use other heat sources of the refrigeration circuit 100A for heating the vehicle interior, such as at least one pre-cooler 120 and / or at least one air cooler 150.

[0077] Furthermore, it is conceivable to dehumidify the air that is heated and introduced into the vehicle interior before heating. For this purpose, at least one evaporator 140A can be used, for example, to cool and dehumidify the air (e.g., via a corresponding secondary or coolant circuit of an indirect cooling and / or heating system) before the air is heated by at least one main radiator 130 or another component.

[0078] Figure 3 schematically shows a refrigeration circuit 100B according to further embodiments of the present disclosure. The circuit of Figure 3 is identical in its basic features to the circuit shown in Figure 2, so reference is made to that figure for a description of the basic components.

[0079] In the example shown in Figure 3, the at least one main heat exchanger includes at least one further evaporator 140B, such as a chiller. The chiller 140B absorbs heat, for example, from a drive system and / or a drive energy storage system of the vehicle, in order to cool the drive system and / or the drive energy storage system. In some embodiments, the refrigeration circuit 100B includes at least one third expansion valve 160C, which is configured to expand the refrigerant into the at least one further evaporator 140B. For example, the at least one third expansion valve 160C can be arranged between an outlet of the at least one inner heat exchanger 170 and an inlet of the at least one further evaporator 140B in the refrigeration circuit 1 OB to expand the refrigerant into the at least one further evaporator 140B.

[0080] The following are some example operating modes for the 100B refrigeration circuit.

[0081] 1. Cooling the drive energy storage system

[0082] The drive energy storage system can be cooled using the Chiller 140B. As described with reference to Figure 1, the refrigerant can absorb heat from the drive energy storage system (e.g., via a corresponding secondary or coolant circuit of an indirect cooling and / or heating system), thereby increasing the enthalpy of the refrigerant. In the log pH diagram, this process is represented as a horizontal shift to the right at low pressure (point 4 to point 1).

[0083] It is conceivable that the third expansion valve 160C is open while the second expansion valve 160B is closed, so that only the drive energy storage system is cooled by the chiller 140B. Alternatively, both the second expansion valve 160B and the third expansion valve 160C can be open, allowing for parallel cooling of the drive energy storage system by the chiller 140B and the vehicle interior by the evaporator 140A. Similarly, the third expansion valve 160C can be closed while the second expansion valve 160B is open, so that only the vehicle interior is cooled by the evaporator 140A.

[0084] 2. Heating the Drive Energy Storage System. Heating the drive energy storage system, e.g., for thermal preconditioning, can be achieved using at least one main cooler 130. As described with reference to Figure 1, the refrigerant can transfer heat to the drive energy storage system (e.g., via a corresponding secondary or coolant circuit of an indirect cooling and / or heating system), thereby reducing the enthalpy of the refrigerant. In the log pH diagram, this process is represented as a horizontal shift to the left at high pressure (point 2 to point 3).

[0085] However, it is also conceivable to use other heat sources of the refrigeration circuit 100A for heating the drive energy storage, such as at least one pre-cooler 120 and / or at least one air cooler 150.

[0086] Figure 4 schematically shows a refrigeration cycle 100C according to further embodiments of the present disclosure. The cycle of Figure 4 is identical in its basic features to the cycles shown in Figures 2 and 3, so reference is made to those for a description of the basic components.

[0087] In the example of Figure 4, the refrigeration circuit 100C includes at least one bypass BP, which connects an outlet of the at least one main cooler 130 and an inlet of the at least one main heat exchanger 140 A or of the at least one second expansion valve 160B.

[0088] In some embodiments, the refrigeration circuit HOC includes at least one fourth expansion valve 160D, which is arranged in the bypass BP to selectively open and close the bypass BP.

[0089] Figure 5 schematically shows a flowchart of method 500 for operating a refrigeration cycle according to embodiments of the present disclosure. Method 500 comprises, in block 510, providing the refrigeration cycle with at least one refrigerant pump configured to compress a refrigerant and circulate it in the refrigeration cycle, wherein the temperature of the refrigerant after compression is higher than a critical temperature of the refrigerant; at least one precooler arranged downstream of the at least one refrigerant pump in the refrigeration cycle and configured to precool the refrigerant compressed by the at least one refrigerant pump; and at least one main cooler arranged downstream of the at least one precooler in the refrigeration cycle and configured to further cool the refrigerant precooled by the at least one precooler.and at least one main heat exchanger arranged downstream of the at least one main cooler in the refrigeration circuit; and in block 520, the operation of at least one refrigerant pump to circulate the refrigerant in the refrigeration circuit.

[0090] According to the invention, a refrigeration circuit architecture is provided that enables the use of a natural refrigerant, such as carbon dioxide or R744. For this purpose, the refrigeration circuit includes a pre-cooler (e.g., a water gas cooler) which is connected as a separate component downstream of the refrigerant pump, so that the refrigerant, which is heated considerably by compression, is pre-cooled immediately after leaving the refrigerant pump. This allows the refrigerant to be fed into the rest of the refrigeration circuit without requiring special adaptations or modifications to components such as the main cooler (e.g., a hot gas cooler installed at the front of a vehicle) or main heat exchangers (e.g., evaporator, chiller, etc.) to cope with the high temperatures of the compressed refrigerant. As a result, a simple circuit architecture for alternative refrigerants, such as carbon dioxide or R744, can be implemented.R744 will be provided.

[0091] Although the invention has been further illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived from them by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned as examples are truly only examples and are not to be understood in any way as limiting, for example, the scope of protection, the possible applications, or the configuration of the invention.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without leaving the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description.

Claims

Patent claims 1. Refrigeration cycle (100A, 100B, 100C), comprising: at least one refrigerant pump (110) configured to compress a refrigerant and circulate it in the refrigeration cycle (100A, 100B, 100C), wherein the temperature of the refrigerant after compression is higher than a critical temperature of the refrigerant; at least one precooler (120) which is arranged downstream of the at least one refrigerant pump (110) in the refrigeration circuit (100A, 100B, 100C) and is configured to precool the refrigerant compressed by the at least one refrigerant pump (110); at least one main cooler (130) arranged downstream of the at least one precooler (120) in the refrigeration circuit (100A, 100B, 100C) and configured to further cool the refrigerant precooled by the at least one precooler (120); and at least one main heat exchanger (14A, 140B) is arranged downstream of the at least one main cooler (130) in the refrigeration circuit (100A, 100B, 100C).

2. Refrigeration circuit (100A, 100B, 100C) according to claim 1, wherein the refrigerant is carbon dioxide, in particular R744.

3. Refrigeration circuit (100A, 100B, 100C) according to claim 1 or 2, wherein: which includes at least one pre-cooler (120) or a water-gas cooler, or is a water-gas cooler; and / or which includes at least one main cooler (130) or is a heating gas cooler.

4. Refrigeration circuit (100A, 100B, 100C) according to one of claims 1 to 3, further comprising at least one air cooler (150) arranged downstream of the at least one main cooler (130) in the refrigeration circuit (100A, 100B, 100C), in particular wherein the refrigeration circuit (100A, 100B, 100C) further comprises at least one first expansion valve (160A) comprises, which is arranged between the at least one main cooler (130) and the at least one air cooler (150) in the refrigeration circuit (100A, 100B, 100C) to expand the refrigerant into the at least one air cooler (150).

5. Refrigeration circuit (100A, 100B, 100C) according to one of claims 1 to 4, further comprising at least one internal heat exchanger (170) which is connected between an outlet of the at least one main cooler (130) and an inlet of the at least one refrigerant pump (110).

6. Refrigeration circuit (100B, 100C) according to one of claims 1 to 5, wherein the at least one main heat exchanger (140A, 140B) comprises: at least one evaporator (140A) configured for interior cooling, in particular wherein the refrigeration circuit (100A, 100B, 100C) further comprises at least one second expansion valve (160B) configured to expand the refrigerant into the at least one evaporator (140B); and / or at least one further evaporator (140B) configured for cooling a drive and / or a drive energy storage device, in particular wherein the refrigeration circuit (100B, 100C) further comprises at least one third expansion valve (160C) configured to expand the refrigerant into the at least one further evaporator (140B).

7. Refrigeration circuit (100A, 100B, 100C) according to one of claims 1 to 6, further comprising at least one refrigerant collector (180) which is connected between an outlet of the at least one main heat exchanger (140A, 140B) and an inlet of the at least one refrigerant pump (110).

8. Refrigeration circuit (100C) according to any one of claims 1 to 7, further comprising at least one bypass (BP) connecting an outlet of the at least one main cooler (130) and an inlet of the at least one main heat exchanger (140A, 140B), in particular wherein the refrigeration circuit (100C) further comprises at least one fourth The expansion valve (160D) is arranged in the bypass (BP) to selectively open and close the bypass (BP).

9. Vehicle, in particular motor vehicle, comprising a cooling and / or heating system with at least one refrigeration circuit (100A, 100B, 100C) according to one of claims 1 to 8.

10. Method (500) for operating a refrigeration circuit (100A, 100B, 100C), comprising: Providing (510) the refrigeration circuit (100A, 100B, 100C) with at least one refrigerant pump (110) configured to compress a refrigerant and circulate it in the refrigeration circuit (100A, 100B, 100C), wherein the temperature of the refrigerant after compression is higher than a critical temperature of the refrigerant; and at least one precooler (120) arranged downstream of the at least one refrigerant pump (110) in the refrigeration circuit (100A, 100B, 100C) configured to precool the refrigerant compressed by the at least one refrigerant pump (110); at least one main cooler (130) which is arranged downstream of the at least one pre-cooler (120) in the refrigeration circuit (100A, 100B, 100C) and is configured to further cool the refrigerant pre-cooled by the at least one pre-cooler (120);and at least one main heat exchanger (140A, 140B) arranged downstream of the at least one main cooler (130) in the refrigeration circuit (100A, 100B, 100C); and operating (520) the at least one refrigerant pump (110) to circulate the refrigerant in the refrigeration circuit (100A, 100B, 100C).

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