Cyclic process device, thermal management system and vehicle

Abstract

The invention relates to a cyclic process device (10), in particular a heat pump, comprising: a refrigerant circuit which is designed for a refrigerant to circulate therein; an evaporator (11) and a condenser (12) which are each arranged in the refrigerant circuit and are designed to exchange thermal energy; at least a first valve (13a) and a second valve (13b) which are arranged in the refrigerant circuit and are designed to adjust a pressure of the refrigerant; at least one compressor unit (14) which is arranged in the refrigerant circuit and is designed to compress the refrigerant; a low-pressure line (N) which extends between the first valve (13a) and the compressor unit (14); a high-pressure line (H) which extends between the compressor unit (14) and the condenser (12); a medium-pressure line (M) which extends between the second valve (13b) and the compressor unit (14); and a drive unit (15) which is designed to drive the compressor unit (14), wherein the drive unit (15) is thermally coupled to the medium-pressure line (M) in order to transfer thermal energy to the refrigerant.

Description

[0001] ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26

[0002] closed-loop process device, thermal management system, and vehicle

[0003] The present invention relates to a cyclic process device, in particular a heat pump, a thermal management system and a vehicle.

[0004] It is known to use thermodynamic devices, such as heat pumps, in electric or hybrid vehicles to provide the necessary heating and cooling for the entire vehicle at the required temperature levels. The heating and cooling capacity of the system can be transferred to the components to be heated and cooled using water. Such a thermodynamic device includes a compressor designed to compress a refrigerant circulating within the heat pump. The compressor can be driven by an electric motor. The efficiency of the electric motor varies depending on the operating point. Any resulting power loss is dissipated as heat. This heat can be carried away via the refrigerant in the thermodynamic device.Introducing heat loss before the compression process reduces the heat absorption potential of the heat pump. This decreases the heat pump's efficiency. Furthermore, introducing heat into the refrigerant before the compressor reduces efficiency and cooling capacity, for example, when the cycle is used as a chiller.

[0005] It has therefore become apparent that there is a need to provide a thermodynamic device that is improved with regard to the thermal energy transferred, especially from the drive engine.

[0006] The object of the present invention is to provide an improved thermodynamic device, which in particular has an improved heat absorption potential. It is further an object of the present invention to provide a thermal management system with such a thermodynamic device and a vehicle. ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26

[0007] The problem is solved by the circular process device with the features of claim 1, by the thermal management system with the features of claim 9, and by a vehicle with the features of claim 10.

[0008] A first aspect of the present invention relates to a cyclic process device, in particular a heat pump, comprising: a refrigerant circuit configured to allow a refrigerant to circulate in it, an evaporator and a condenser, each arranged in the refrigerant circuit and configured for the exchange of thermal energy, at least a first valve and a second valve arranged in the refrigerant circuit and configured to adjust the pressure of the refrigerant, at least one compressor unit arranged in the refrigerant circuit and configured to compress the refrigerant, a low-pressure line extending between the first valve and the compressor unit, a high-pressure line extending between the compressor unit and the condenser, and a medium-pressure line extending between the second valve and the compressor unit, and a drive unit configured toto drive the compressor unit, wherein the drive unit is thermally coupled to the medium-pressure line in order to transfer thermal energy to the refrigerant.

[0009] Compared to the prior art, the present invention offers the advantage that the transfer of power losses in the low-pressure line by the drive unit upstream of the compressor unit can be reduced. This increases the cooling capacity of the heat pump by avoiding additional heat absorption in the low-pressure line. Furthermore, the heating capacity of the heat pump can be increased by increasing the refrigerant mass flow rate at the condenser via the medium-pressure line. Finally, the efficiency of the heat pump can be increased because the electrical energy required for thermal output is reduced.

[0010] The cycle device can preferably be a heat pump. The cycle device can be designed to accommodate a refrigerant. More precisely, the cycle device can be designed to accommodate a ZF Friedrichshafen AG file 304894 Friedrichshafen 2024-09-26

[0011] to have a refrigerant circuit in which the refrigerant can circulate in one flow direction.

[0012] A thermodynamic cycle can be understood as a sequence of state changes of a fluid, referred to as the working fluid (e.g., a refrigerant), along a closed trajectory within the fluid's state space. The working fluid or refrigerant can be a liquid, vapor, and / or a gas. During the cycle, the working fluid or refrigerant can only pass through states that are in thermodynamic equilibrium. The state changes in the working fluid or refrigerant can be triggered by changes in state variables such as pressure, temperature, or volume. Typically, mechanical and thermal energy are converted into one another during the passage of a thermodynamic cycle.Since the corresponding forms of energy transport, mechanical work and heat, are process variables, the amount of mechanical work performed by or on the working medium and the amount of heat absorbed or released by the working medium depend on the path of the cycle. Thermodynamic cycles are used, for example, to model the operation of heat pumps and refrigeration machines, such as refrigerators. Ideal Carnot cycles, in which a working medium is alternately brought into contact with two given heat reservoirs, define the theoretically possible maximum efficiency under these conditions.

[0013] The first valve allows a low-pressure level to be set in the low-pressure line, and the second valve allows a medium-pressure level to be set in the medium-pressure line. The first and second valves can preferably be designed or configured as expansion valves. In particular, the first and / or the second valve can be designed as a direct-acting valve. This makes it possible to actively set or vary the pressure level in the refrigerant circuit.

[0014] The refrigerant circuit has a piping system designed to allow the refrigerant to flow through it. The piping system can comprise several lines (ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26). The components of the cycle device are at least indirectly interconnected via the piping system.

[0015] The evaporator and condenser are heat exchangers, in particular plate heat exchangers. The evaporator and condenser are preferably thermally coupled to a refrigerant circuit. The refrigerant circuit is designed to be circulated by a refrigerant. In particular, the evaporator can be thermally coupled to a low-temperature circuit and the condenser to a high-temperature circuit. The evaporator is designed to transfer thermal energy from the refrigerant in the low-temperature circuit to the refrigerant in the refrigerant circuit. The condenser is designed to transfer thermal energy from the refrigerant in the refrigerant circuit to the refrigerant in the high-temperature circuit.

[0016] The compressor unit is designed to compress the refrigerant in the refrigerant circuit. The compressor unit can, for example, be a scroll compressor. The compressor unit is located in the refrigerant circuit downstream of the evaporator in the refrigerant flow direction. The refrigerant compressed by the compressor unit is in a gaseous state.

[0017] The drive unit can be integrated with the compressor unit as a single component. The drive unit is preferably arranged upstream of the compressor unit in the refrigerant flow direction. The drive unit is designed to drive the compressor unit and is thermally coupled to the refrigerant circuit to transfer thermal energy to the refrigerant. The drive unit is preferably designed as an electric motor. The drive unit is designed to be located in or connected to the medium-pressure line and to be at least partially cooled by the refrigerant flow. For example, the refrigerant can flow through a stator and / or a rotor of the drive unit. This allows the drive unit to transfer thermal energy to the refrigerant, thus cooling the drive unit. ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26

[0018] The low-pressure line extends between the first valve and the compressor unit. The high-pressure line extends between the compressor unit and at least the condenser. Preferably, the high-pressure line extends to the first valve or to the second valve. The intermediate-pressure line extends between the second valve and the compressor unit. The low-pressure line is configured to carry a refrigerant mass flow set at a low-pressure level. The intermediate-pressure line is configured to carry a refrigerant mass flow set at an intermediate-pressure level, where the intermediate-pressure level is higher than the low-pressure level. The high-pressure line is configured to carry a refrigerant mass flow set at a high-pressure level, where the high-pressure level is higher than the intermediate-pressure level.The medium-pressure line is connected in parallel to the low-pressure line. This parallel connection divides the refrigerant mass flow. The refrigerant mass flow at the medium-pressure level can be introduced into the compressor unit or a compressor by injection during the compression process. For example, the refrigerant at the medium-pressure level can be injected through an opening in the stationary scroll of a scroll compressor. Introducing the power loss from the drive unit in the form of heat at the medium-pressure level allows refrigerant to evaporate at this level, and this medium-pressure mass flow can then be introduced into the compression process to increase the refrigerant mass flow at the condenser. Preferably, the low-pressure line and the medium-pressure line carry different refrigerant mass flows. The refrigerant mass flow at the condenser or...The refrigerant mass flow rate in the high-pressure line is the sum of the refrigerant mass flow rate at the evaporator or in the low-pressure line and the refrigerant mass flow rate through the medium-pressure line. The refrigerant mass flow rate through the low-pressure line is preferably greater than the refrigerant mass flow rate through the medium-pressure line. The increased refrigerant mass flow rate in the high-pressure line at the condenser increases the heating capacity of the heat pump. ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26.

[0019] In one embodiment, the cyclic device comprises a control unit configured to control the first valve and / or the second valve based on temperature information. The first valve and / or the second valve can be configured as controllable valves. The first valve and / or the second valve are preferably connected to the control unit via signal transmission. Each of the two valves can include its own control unit.

[0020] In one embodiment, the control unit is configured to control the drive unit based on temperature information. The control unit can be connected to the drive unit via signal transmission. In particular, the control unit can be configured to control the power, especially the power loss, of the drive unit. Power loss refers to the power of the drive unit that is transferred as thermal energy to the refrigerant in the coolant circuit. For example, the control unit is configured to control the power electronics of the drive unit. The power electronics can comprise various electronic components. For example, the power electronics can include a power converter, a rectifier, an inverter, a DC-DC converter, and / or a frequency converter.In particular, the drive unit can be designed to compensate for a difference between a target refrigerant temperature and the actual refrigerant temperature. For example, the control unit can control the drive unit based on temperature information, such as the actual temperature, resulting in a higher power loss from the drive unit. This higher power loss is transferred to the refrigerant in the refrigerant circuit via thermal coupling between the drive unit and the circuit. This allows the actual refrigerant temperature to be regulated. This means that the actual temperature is at least approximated to a target temperature. The control unit can thus be designed to actively adjust the power loss of the drive unit to transfer thermal energy to the refrigerant in the circuit, ensuring that a favorable temperature level in the refrigerant circuit is maintained.

[0021] In one embodiment, the control unit is designed to control the drive unit, the first valve and / or the second valve based on the obtained ZF Friedrichshafen AG file 304894 Friedrichshafen 2024-09-26

[0022] Temperature information is used to control the system. In particular, the control unit can be connected to the valves and the drive unit. This allows the drive unit's power loss and the refrigerant mass flow to be adjusted as needed to increase the heat pump's efficiency.

[0023] In one embodiment, a temperature sensor is arranged in the refrigerant circuit and / or the coolant circuit to detect temperature information. This temperature information can be indicative of the temperature of the refrigerant and / or a coolant. The temperature sensor in the coolant circuit, particularly in a low-temperature circuit, can determine whether the coolant circuit temperature is sufficient to transfer enough thermal energy to the refrigerant so that a preferred temperature level of the refrigerant is not undershot. Furthermore, the temperature sensor can be arranged in a high-temperature coolant circuit or a heating circuit. This allows the system to determine whether a temperature level required for heating is present in the high-temperature circuit or the heating circuit. The temperature sensor in the refrigerant circuit allows for direct monitoring of the preferred temperature level.For this purpose, the temperature sensor is preferably located in the low-pressure line in the area of ​​the evaporator or compressor unit. The temperature sensor can be, for example, an invasive or a non-invasive temperature sensor.

[0024] In one embodiment, the first and second valves are arranged in series or in parallel. In other words, the second valve can be arranged parallel to the first valve. Alternatively, the two valves can also be arranged in series, with a branch of the refrigerant mass flow occurring between the two valves at the intermediate pressure level. This branch directs part of the refrigerant mass flow to the intermediate pressure line and another part to the low pressure line. In a series arrangement of the valves, the second valve is located upstream of the first valve in the direction of fluid flow, so that the refrigerant mass flow is initially set to the intermediate pressure level. Subsequently, downstream of the second valve in the direction of flow, the branch splits the refrigerant mass flow set to the intermediate pressure level.Part of the refrigerant mass flow is directed into the medium-pressure line (ZF Friedrichshafen AG File 304894, Friedrichshafen, 2024-09-26), and another part is directed into the low-pressure line. After the branch, the first valve in the low-pressure line further reduces the pressure level and adjusts it to the low-pressure level.

[0025] In one embodiment, the temperature sensor is located in the low-pressure line and / or the medium-pressure line. This allows for the acquisition of a current temperature reading in the medium-pressure line and / or the low-pressure line. Both temperature values ​​can be part of the temperature information transmitted to the control unit, which can be used to control the actuator and / or the first valve and / or the second valve. For example, the temperature information from the low-pressure line and the medium-pressure line can be evaluated or compared to vary the refrigerant mass flow rates.

[0026] In one embodiment, the intermediate-pressure line is coupled to the compressor unit in such a way that the refrigerant from the intermediate-pressure line can be fed into the compressor unit during a compression process. This means that the refrigerant at the intermediate oil pressure level is fed to the refrigerant from the low-pressure line during the compression process. For example, this can be achieved in a scroll compressor by means of an injection port in a stationary screw.

[0027] In one embodiment, a heat exchanger, in particular a precooler, is arranged in the medium-pressure line. The heat exchanger or precooler can be an additional water-to-refrigerant heat exchanger that essentially performs the same function as the evaporator. It is circulated by the refrigerant at medium pressure and enables heat transfer from the cooling water to the refrigerant. The cooling water can, for example, be passed first through the precooler or heat exchanger and then through the evaporator in a counterflow configuration. Part of the water's cooling process thus takes place in the precooler or heat exchanger. Only a smaller amount of heat then needs to be extracted from the precooled water in the evaporator. This means that only a smaller refrigerant mass flow rate is required in the low-pressure line at the low-pressure level.

[0028] Another aspect of the present invention relates to a thermal management system with a cycle process device according to one of the preceding embodiments.

[0029] Another aspect of the present invention relates to a vehicle with a thermal management system according to the preceding claim or a cycle process device according to one of the preceding embodiments.

[0030] Furthermore, a method for controlling a refrigerant mass flow in a cyclic process device, in particular according to one of the preceding embodiments, is possible, wherein the method comprises the following steps: obtaining at least one temperature information; controlling a drive unit and / or a first valve and / or a second valve depending on the temperature information.

[0031] Embodiments are formed. Advantages and further developments mentioned for the features or embodiments also apply analogously to the new embodiments. Further developments and advantages mentioned in connection with the device also apply analogously to the system and vice versa.

[0032] Advantageous embodiments of the invention are described in detail below with reference to the accompanying figures:

[0033] Figure 1 is a schematic view of a circular process device according to an embodiment of the present invention;

[0034] Figure 2 is a schematic view of another circular process device according to an embodiment of the present invention; ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26

[0035] Figure 1 shows a refrigerant circuit of a cycle device 10. The direction of refrigerant flow is indicated by the arrows. The cycle device 10 comprises an evaporator 11, a condenser 12, a first valve 13a, a second valve 13b, and a compressor unit 14. The compressor unit 14 is arranged downstream of the evaporator 11 in the direction of refrigerant flow. The condenser 12 is arranged downstream of the compressor unit 14 in the direction of refrigerant flow. The first valve 13a and the second valve 13b are arranged downstream of the condenser 12 in the direction of refrigerant flow.

[0036] In the downstream direction of refrigerant flow, a high-pressure line H is arranged between the compressor unit 14 and the condenser 12. A low-pressure line N is arranged in the flow direction between the first valve 13a and the compressor unit 14. A medium-pressure line M is arranged in the flow direction between the second valve 13b and the compressor unit 14. The refrigerant in the low-pressure line N is set to a low-pressure level by the first valve 13a. The refrigerant in the medium-pressure line M is set to a medium-pressure level by the second valve 13b. The refrigerant in the high-pressure line H is set to a high-pressure level by the compressor unit 14. The second valve 13b is arranged in the medium-pressure line M. The second valve 13b sets the medium-pressure level in the medium-pressure line M. The first valve is arranged in the low-pressure line N.More precisely, the first valve 13a can define the low-pressure line N and the second valve 13b can define the medium-pressure line.

[0037] In Figure 1, the first valve 13a and the second valve 13b are connected in parallel. Downstream of the condenser 12, the refrigerant circuit has a branch 16. After branch 16, high-pressure line H splits into two lines. Branch 16 divides the refrigerant mass flow into two smaller refrigerant mass flows. The magnitude of the refrigerant mass flows is schematically represented by the thickness of the arrows. Between the compressor unit 14 and branch 16, i.e., in high-pressure line H, the refrigerant mass flow is greatest. After branch 16, the refrigerant mass flow splits between the ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26

[0038] low-pressure line N and medium-pressure line M, wherein the refrigerant mass flow rate in the low-pressure line N is greater than the refrigerant mass flow rate in the medium-pressure line M.

[0039] The intermediate pressure line M is connected in parallel to the low pressure line N. The intermediate pressure level is defined as being higher than the low pressure level at the evaporator 11 and lower than the high pressure level at the condenser 12. The refrigerant mass flow at the intermediate pressure level can be introduced into the compressor unit 14 by injection during the compression process. Introducing the electrical power loss in the form of heat at the intermediate pressure level allows refrigerant to evaporate at this level, and this intermediate pressure mass flow can then be introduced into the compression process to increase the refrigerant mass flow at the condenser 12. The refrigerant mass flow at the condenser 12 is the sum of the refrigerant mass flow at the evaporator 12 (or the low pressure line N) and the refrigerant mass flow in the intermediate pressure line.The increased refrigerant mass flow at condenser 12 increases the heating power of the cycle device.

[0040] Figure 2 shows an alternative configuration of the two valves 13a and 13b. In Figure 2, the first valve 13a and the second valve 13b are connected in series. Downstream of the condenser 12 in the refrigerant flow direction, the second valve 13b is arranged, which sets the intermediate pressure level of the refrigerant. Downstream of the second valve 13b, the first valve 13a is arranged in series. The first valve 13a sets the low pressure level in the low-pressure line N. The branch 16 is arranged between the second valve 13b and the first valve 13a. In other words, the refrigerant mass flow is divided between the second valve 13b and the first valve 13a.

[0041] The evaporator 11 is coupled to a cooling water circuit KK for transferring thermal energy. The evaporator 11 is designed to extract thermal energy from the cooling water circuit KK. The condenser 12 is connected to a ZF Friedrichshafen AG file 304894 Friedrichshafen 2024-09-26

[0042] Heating water circuit HK is coupled for the transfer of thermal energy. The capacitor 12 is designed to supply thermal energy to the heating water circuit HK.

[0043] The compressor unit 14 is operatively connected to a drive unit 15. In other words, the drive unit 15 drives the compressor unit 14. The drive unit 15 is coupled to the medium-pressure line M for the transfer of thermal energy.

[0044] This means that the drive unit 15 is cooled by the refrigerant, at least in sections. It is possible that individual components, such as a rotor and / or a stator, of the drive unit 15 are exposed to the refrigerant flow.

[0045] The first valve 13a and / or the second valve 13b can be connected to a control unit (not shown) via a signal. The control unit can, in turn, be configured to obtain temperature information. This temperature information can be provided, for example, by a temperature sensor (not shown). The refrigerant mass flow in the low-pressure line and / or in the medium-pressure line M can be varied as needed by means of the two valves 13a and 13b to enable the most efficient operation possible of the cycle device 10.

[0046] The drive unit 15 can be signal-connected to the control unit (not shown). The control unit serves to control the drive unit 15. For example, the drive unit 15 can be operated with a low efficiency, i.e., with high power loss, using a special current-carrying strategy. For this purpose, the drive unit 15 can have additional or special loads or resistors. The power loss of the drive unit 15 is transferred to the refrigerant. This allows additional thermal energy to be transferred to the refrigerant. The control unit makes it possible to actively control or vary the amount of thermal energy to be transferred to the refrigerant. In this way, the refrigerant in the refrigerant circuit can be maintained at a preferred or efficient temperature level. ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26

[0047] Other embodiments of the present invention are possible and can be understood and carried out by persons skilled in the art when applying the claimed subject matter by studying the figures, the disclosure, and the appended claims. In particular, the respective parts / functions of each embodiment described above can also be combined with one another. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are mentioned in interdependent claims does not mean that a combination of these measures cannot be advantageous. Any reference numerals in the claims should not be interpreted as limiting the scope of the claims.

[0048] ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26

[0049] Reference sign

[0050] H High-pressure line

[0051] M Medium pressure line

[0052] N Low-pressure line

[0053] HK heating water circuit

[0054] KK cooling water circuit

[0055] 10 Circular process device

[0056] 11 evaporators

[0057] 12 Capacitor

[0058] 13a first valve

[0059] 13b second valve

[0060] 14 Compressor unit

[0061] 15 Drive unit

[0062] 16 Junction

Claims

ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26 Patent claims 1. Cyclic process device (10), in particular a heat pump, comprising: - a refrigerant circuit designed to allow a refrigerant to circulate within it, - an evaporator (11) and a condenser (12), each arranged in the refrigerant circuit and designed for the exchange of thermal energy, - at least a first valve (13a) and a second valve (13b) arranged in the refrigerant circuit and designed to adjust the pressure of the refrigerant, - at least one compressor unit (14) arranged in the refrigerant circuit and designed to compress the refrigerant, - a low-pressure line (N) extending between the first valve (13a) and the compressor unit (14), a high-pressure line (H) extending between the compressor unit (14) and the condenser (12), and a medium-pressure line (M) extending between the second valve (13b) and the compressor unit (14), - a drive unit (15) designed to drive the compressor unit (14), wherein the drive unit (15) is thermally coupled to the medium pressure line (M) to transfer thermal energy to the refrigerant.

2. Cycle process device (10) according to claim 1, wherein the cycle process device (10) comprises a control unit configured to control the first valve (13a) and / or the second valve (13b) on the basis of temperature information.

3. Cyclic process device (10) according to claim 1 or 2, wherein the control unit is configured to control the drive unit (15) on the basis of the temperature information. ZF Friedrichshafen AG File 304894 Friedrichshafen 2024-09-26 4. Cycle process device (10) according to one of the preceding claims, wherein a temperature sensor for detecting the temperature information is arranged in the refrigerant circuit and / or in the coolant circuit, 5. Cycle process device (10) according to one of the preceding claims, wherein the temperature sensor is arranged in the low-pressure line (N) and / or in the medium-pressure line (M).

6. Circular process device (10) according to one of the preceding claims, wherein the first valve (13a) and the second valve (13b) are arranged in series or in parallel.

7. Circular process device (10) according to one of the preceding claims, wherein the medium pressure line (M) is coupled to the compressor unit (14) in such a way that the refrigerant from the medium pressure line (M) can be supplied to the compressor unit (14) during a compression process.

8. Cycle process device (10) according to one of the preceding claims, wherein a heat exchanger, in particular a precooler, is arranged in the medium pressure line (M).

9. Thermal management system with a cycle process device (10) according to one of the preceding claims.

10. Vehicle with a thermal management system according to the preceding claim or a cycle process device (10) according to any of the preceding claims.

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