Circulating thermodynamic process system with cooling function for its electric machine

Abstract

The present invention relates to a cyclic thermodynamic process system (20) comprising a first heat exchanger (21), a pressure increasing device (23), a second heat exchanger (24), and a pressure decreasing device (26, 37). The first heat exchanger (21) is designed to heat the process medium, thereby absorbing thermal energy; the pressure increasing device (23) is designed to increase the pressure of the process medium downstream of the first heat exchanger (21) and upstream of the second heat exchanger (24); the second heat exchanger (24) is designed to cool the process medium, thereby dissipating thermal energy; and the pressure decreasing device (26, 37) is designed to decrease the pressure of the process medium downstream of the second heat exchanger (24) and upstream of the first heat exchanger (21). The pressure increasing device (23) is part of a hermetically sealed turbine assembly (27) having a motor (28), and the process medium for cooling the turbine assembly (27) may branch off downstream of the second heat exchanger (24).

Description

[0001] This invention relates to cyclic thermodynamic process systems, and in particular, to heat pump systems or refrigeration systems or combinations thereof.

[0002] A cyclic thermodynamic process system (such as a heat pump system or a refrigeration system) includes a first heat exchanger, a pressure-increasing device, a second heat exchanger, and a pressure-reducing device. The first heat exchanger is designed to heat the process medium while absorbing heat energy through it, wherein the heat energy absorbed by the process medium is provided by an exothermic process. The pressure-increasing device is designed to increase the pressure of the process medium downstream of the first heat exchanger and upstream of the second heat exchanger. The second heat exchanger is designed to cool the process medium while releasing heat energy from it, wherein the process medium releases heat energy to a heat-consuming process. The pressure-reducing device is designed to reduce the pressure of the process medium downstream of the second heat exchanger and upstream of the first heat exchanger.

[0003] In heat pump systems, the heat release process can involve the environment, such as ambient air, river or lake water, etc. Similarly, in refrigeration systems, the heat absorption process can involve the environment.

[0004] A cyclic thermodynamic process system is needed, and in particular, a heat pump system or refrigeration system that can operate with high efficiency is needed.

[0005] From this perspective, the present invention is based on the goal of creating a novel cyclic thermodynamic process system.

[0006] This objective is achieved through the cyclic thermodynamic process system according to claim 1.

[0007] In the cyclic thermodynamic process system according to the invention, the pressure increasing device is part of a hermetically sealed turbine assembly, wherein the pressure increasing device is preferably designed as a compressor and includes at least one single-stage or multi-stage compressor section for increasing the pressure of the process medium. In the cyclic thermodynamic process system according to the invention, the hermetically sealed turbine assembly includes a motor, which, together with the pressure increasing device, is preferably arranged in a common hermetically sealed single or multi-piece housing and mounted in the housing via an active magnetic bearing. The process medium for cooling the turbine assembly may branch off downstream of a second heat exchanger.

[0008] The cyclic thermodynamic process system according to the invention can operate with high efficiency. The pressure increasing device is part of a hermetically sealed turbine assembly, which further includes an electric motor. The process medium for cooling the hermetically sealed turbine assembly (especially the electric motor) can branch off downstream of the second heat exchanger.

[0009] Cyclic thermodynamic process systems can operate with high efficiency. This efficiency depends on the ratio of the generated heat or cold output to the pressure increase output required by the pressure-increasing device. No additional pressure increase output is needed to supply the process medium required for cooling turbine components. The process medium for cooling the motor branches off at the lowest possible temperature, resulting in optimal cooling of the hermetically sealed turbine components.

[0010] Frictional losses of the process medium in the motor area are kept to a minimum. In the rotor-stator clearance of the motor in the hermetically sealed turbine assembly, the process medium used to cool the motor exists in the vapor phase.

[0011] Preferably, the process medium used to cool the turbine components can branch off directly downstream of the second heat exchanger. This direct downstream branching of the process medium for cooling the turbine components allows for particularly efficient operation of the cyclic thermodynamic process system.

[0012] Preferably, the circulating thermodynamic process system includes a throttling device designed to expand the process medium branching off downstream of the second heat exchanger. Furthermore, the circulating thermodynamic process system preferably includes a phase separator to separate the gaseous and liquid phases of the branched-off and expanded process medium, wherein at least the gaseous phase of the branched-off and expanded process medium is used to cool turbine components, particularly the rotor of the turbine motor. Preferably, the liquid phase of the branched-off and expanded process medium is also used to cool the turbine components, particularly the stator of the turbine motor. This allows for advantageous cooling of the turbine components while ensuring efficient operation of the circulating thermodynamic process system. The gaseous phase of the branched-off process medium expanding at the throttling device is used at least to cool the turbine components. Optionally, the liquid phase of the process medium branching off at the throttling device can also be used for cooling.

[0013] Preferred alternative developments of the invention are obtained from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail by way of the accompanying drawings, but are not limited thereto. Here, the drawings show: Figure 1a The first cycle thermodynamic process system according to the present invention is used as a heat pump system; Figure 1b : Figure 1a Pressure-enthalpy diagram of a heat pump system; Figure 2a The second-cycle thermodynamic process system according to the present invention, used as a heat pump system; Figure 2b : Figure 2a Pressure-enthalpy diagram of a heat pump system; Figure 3aThe third-cycle thermodynamic process system according to the present invention is used as a heat pump system; Figure 3b : Figure 3a Pressure-enthalpy diagram of a heat pump system; Figure 4a The fourth cycle thermodynamic process system according to the present invention is used as a heat pump system; Figure 4b : Figure 4a Pressure-enthalpy diagram of a heat pump system; Figure 5a The fifth cycle thermodynamic process system according to the present invention, used as a heat pump system; Figure 5b : Figure 5a Pressure-enthalpy diagram of a heat pump system; Figure 6a The sixth cycle thermodynamic process system according to the present invention is used as a heat pump system; Figure 6b : Figure 6a Pressure-enthalpy diagram of a heat pump system; Figure 7a : An additional cyclic thermodynamic process system according to the present invention used as a heat pump system; Figure 7b : Figure 7a Pressure-enthalpy diagram of a heat pump system.

[0014] This invention relates to a cyclic thermodynamic process system. This cyclic thermodynamic process system can be a heat pump system, a refrigeration system, or a combination of a heat pump system and a refrigeration system. In each case, reference will be made below. Figures 1a to 7b The invention is described in the context of heat pump systems.

[0015] Figure 1a A first heat pump system 20 according to the present invention is shown. Figure 1b The pressure (p) and enthalpy (h) diagrams for heat pump system 20 are shown.

[0016] exist Figure 1b The pressure (p) enthalpy (h) diagram shows the various states of the process medium: 0, 1, 2, 3, 4, 5, 6, 7, and 8. Figure 1a The flow-side position in heat pump system 20 indicates the corresponding states 0, 1, 2, 3, 4, 5, 6, 7, and 8 in which the process medium is present.

[0017] Figure 1a The heat pump system 10 has a first heat exchanger 21, which heats the process medium while absorbing heat energy from the exothermic process 22. In the region of the first heat exchanger 21, the process medium absorbs heat energy accordingly, and the process medium changes from state 5 to state 0.

[0018] In addition, the heat pump system 20 has a pressure increasing device 23, which in turn... Figure 1a In an exemplary embodiment, the device is formed by two compressor sections 23a and 23b. Each of the compressor sections 23a and 23b of the pressure increasing device 23 may be a single-stage or multi-stage design and is used to increase the pressure of the process medium downstream of the first heat exchanger 21 and upstream of the second heat exchanger 24. Compressor section 23a compresses the process medium from state 1 to state 2, and compressor section 23b compresses the process medium from state 2 to state 3.

[0019] The second heat exchanger 24 is designed to cool the process medium while releasing heat energy from the process medium to the endothermic process 25. In the second heat exchanger 24, the process medium transitions from state 3 to state 4.

[0020] also, Figure 1a The heat pump system 20 includes a pressure reduction device 26, which in turn... Figure 1a In an exemplary embodiment, an expansion valve is used to expand the process medium from state 4 to state 5.

[0021] The pressure increasing device 23, having its two compressor sections 23a and 23b, is part of the hermetically sealed turbine assembly 27. The motor 28 is also part of this hermetically sealed turbine assembly 27. The pressure increasing device 23 and the motor 28 are arranged within a common hermetically sealed single or multi-piece housing 29 of the hermetically sealed turbine assembly 27, wherein the housing 29 is within... Figure 1a The pressure increasing device 23 (i.e., its compressor sections 23a, 23b) and the motor 28 are preferably mounted in the housing 29 via an active magnetic bearing (not shown).

[0022] The coolant required for cooling the hermetically sealed turbine assembly 27 is provided downstream of the second heat exchanger 24 (i.e., directly downstream of the second heat exchanger 24). The process medium is branched off from the closed heat pump loop via a branch line 30 and supplied to the turbine assembly 27 for cooling via a supply line 31. A throttling device 32 is integrated into the branch line 30, causing the branched-off process medium for cooling to expand, i.e., expand from state 4. In state 4, a liquid process medium is present, which is partially converted into a gas phase and partially into a liquid phase by the throttling device 32. The gas phase has state 6, and the liquid phase has state 7.

[0023] The gas phase is separated from the liquid phase in phase separator 33. Supply line 31 supplies the gas phase from phase separator 33 to hermetically sealed turbine assembly 27 for cooling hermetically sealed turbine assembly 27. The liquid phase from phase separator 33 can be mixed with the process medium expanding in the region of throttle valve 26 for subsequent reheating by first heat exchanger 21.

[0024] exist Figure 1b In the pressure (p) enthalpy (h) diagram, state 7 is located on the liquid saturation line I, and states 0 and 6 are located on the gas saturation line II. Between the liquid saturation line I and the gas saturation line II, the process medium is located in region III, where the process medium exists in vapor-liquid equilibrium.

[0025] To the left of the liquid saturation line I in region IV, there exists a subcooled liquid phase, and to the right of the vapor saturation line II in region V, there exists a superheated gas phase. Above the critical point VI, the process medium is in a supercritical state.

[0026] The pressure increasing device 23 and the motor 28 are part of the airtight turbine assembly 27. Figure 1a The heat pump system 10 can operate with high efficiency. As a coolant for cooling the turbine assembly 27, the refrigerant branches off directly downstream of the second heat exchanger 24 from the closed heat pump loop, where... Figure 1a In an exemplary embodiment, only the gaseous phase of the branched-out and expanded process medium is used to cool the hermetically sealed turbine assembly 27, i.e., the motor 28. For this purpose, the gaseous phase is supplied to the turbine assembly in state 6. The process medium is heated to state 8 by means of motor loss absorption. Thereafter, the process medium branched out in state 8 for cooling is mixed with the process medium in the main loop to state 0 to achieve process medium in state 1, wherein process medium in state 1 is supplied in the direction of compressor section 23a for compression.

[0027] Figure 1a An additional throttling device 34 is shown so that the liquid phase of the liquid process medium discharged from the phase separator 33 expands from state 7 to state 5.

[0028] Figure 2a Show Figure 1a Another development scheme for the heat pump system 20, Figure 2b The associated pressure (p) enthalpy (h) diagram is shown. Figure 1a Heat pump system 20 and Figure 2a The only difference between the heat pump systems 20 and 20 is that: Figure 2aIn the heat pump system 20, there is also a regenerative heat exchanger 35. On the one hand, the process medium leaving the second heat exchanger 24 flows through the regenerative heat exchanger 35, and on the other hand, the process medium leaving the first heat exchanger 21 flows through the regenerative heat exchanger 35 for heat recovery.

[0029] Through branch line 30, the process medium branches off again from the closed heat pump loop directly downstream of the second heat exchanger 24 and is guided in the direction of the phase separator 33 via the throttling device 32, wherein... Figure 2a In the process, the gas phase is converted and supplied to the turbine assembly 27 via supply line 31 for cooling the turbine assembly 27. Because... Figure 2a The fact that the heat pump system 20 further includes a regenerative heat exchanger 35 means that the state of the heat pump system with respect to its process medium is also different, in which... Figure 2b and Figure 2a In the diagram, the corresponding states 1 to 10 of the process medium are shown in the pressure (p) enthalpy (h) diagram and in the regions of the corresponding components of the process medium, where these states occur.

[0030] As already explained, in Figure 2a In the case of heat pump system 20, the process medium used as coolant for hermetically sealed turbine assembly 27 also branches off from the heat pump loop directly downstream of the second heat exchanger 24 (i.e., upstream of the regenerative heat exchanger 35).

[0031] Figure 3a Show Figure 2a A variant of the heat pump system 20, which is related to Figure 2a The difference between the heat pump system 20 and the heat pump system 20 is that: Figure 3a In the heat pump system 20, not only is a gas phase supplied from the phase separator 33 via supply line 31 to the hermetic sealed turbine assembly 27 for cooling, but a liquid phase is also supplied via a separate supply line 36. The gas phase is specifically used to cool the rotor of the motor 28 of the hermetic sealed turbine assembly 27, and the liquid phase is specifically used to cool the stator of the motor 28. Figure 3b Showing for Figure 3a The pressure (p) and enthalpy (h) diagram of the heat pump system 20 and the state of the process medium.

[0032] Figure 1a , Figure 2a and Figure 3a The heat pump system 20 is particularly suitable for use in subcritical cycle processes, especially when propane is used as the process medium. However, the heat pump system 20 can also be used in supercritical cycle processes, especially when CO2 is used as the process medium.

[0033] Figure 4a Show Figure 2a A variant of the heat pump system 20. Figure 4a Heat pump system 20 and Figure 2a The difference between heat pump systems 20 and 20 is that: Figure 4a In addition to the pressure increasing device 23 and the motor 28, the hermetically sealed turbine assembly 27 also includes a turbine 37 as a separate component. The turbine 37, together with the expansion valve 26 and optionally an additional expansion valve 42, forms a pressure reducing device. The turbine 37, along with the motor 28 and the compressor 23, is arranged within the hermetically sealed housing 29 of the turbine assembly 27, wherein the turbine 37 is preferably mounted via an active magnetic bearing. Figure 4a In this process, the process medium can also branch off from the closed heat pump loop via branch line 30 and be supplied to phase separator 33 via throttling device 32, wherein from phase separator 33, the gas phase for cooling is guided via supply line 31 in the direction of hermetically sealed turbine assembly 27, but with Figure 2a In contrast, it is guided via a separate drying unit 38. Specifically, such a drying unit 38 is used when the process medium contains moisture or is damp due to further pressure reduction. Thermal energy is required in the drying unit 38 to dry the gas phase guided from the phase separator 31 in the direction of the turbine assembly 27; this thermal energy can be recovered from the refrigerant already guided via the motor 28 within the region of the drying unit 38. Figure 4b In the middle, it is shown again for Figure 4a The state of the process medium in the heat pump system 20, wherein states 3, 4 and 5 are located in Figure 4b In the supercritical region VII of the pressure (p) enthalpy (h) diagram.

[0034] Figure 5a Show Figure 4a A variant of the heat pump system 20, wherein... Figure 5a In this process, starting from phase separator 33, the liquid phase of the process medium used to cool turbine assembly 27 is also guided in the direction of the hermetically sealed turbine assembly, specifically so as to conform to... Figure 3a As in the exemplary embodiment, the rotor is cooled via the gas phase and the stator of motor 28 is cooled via the liquid phase. The corresponding states of the process media are again shown in... Figure 5b The pressure (p) and enthalpy (h) diagram.

[0035] Another heat pump system 20 according to the invention is shown in Figure 6a Among them Figure 6a The heat pump system 20 is Figure 1a Another development scheme for the heat pump system 20, and in accordance with Figure 1aAs in the exemplary embodiment, it includes two compressor sections 23a and 23b, which are arranged together with the motor 28 in the housing 29 of the hermetically sealed turbine assembly 27.

[0036] exist Figure 6a In the heat pump system 20, not only does the refrigerant used to cool the turbine assembly 27 branch off from the closed heat pump loop directly downstream of the second heat exchanger 24 via branch line 30, but a portion of the process medium leaving the second heat exchanger 24 is also guided via another branch line 39 in the direction of the compressor section 23 so as to be compressed together with the process medium leaving the compressor section 23a in the region of the compressor section 23b. A throttle valve 40 is used for pressure balancing of the process medium. Figure 6a The state of the process medium in the heat pump system 20 is shown in Figure 6b The pressure (p) and enthalpy (h) diagram.

[0037] Figure 7a Show Figure 6a Another development scheme for the heat pump system 20, in which Figure 7a heat pump systems and Figure 6a The difference between heat pump systems and heat pump systems lies in: Figure 6a In contrast, not only the gas phase but also the liquid phase is used to cool the hermetically sealed turbine assembly 27 via the process medium branched out through branch line 30. For Figure 7a The relevant states of the process medium in the heat pump system 20 are shown in Figure 7b The pressure (p) and enthalpy (h) diagram.

[0038] All the heat pump systems 20 shown share a common feature: the heat pump system 20 includes a hermetically sealed turbine assembly 27, which includes at least a pressure increasing device 23 and a motor 28. To cool the turbine assembly 27, refrigerant is branched off from the closed heat pump loop directly downstream of the second heat exchanger 24 via a branch line 30, wherein at least the gaseous phase and optionally the liquid phase of the branched-off and expanding process medium are used to cool the hermetically sealed turbine assembly 27.

[0039] This invention allows for efficient operation of the heat pump system 20. The process medium branching off from the closed heat pump loop directly downstream of the second heat exchanger 24 for cooling the turbine assembly 27 has a low temperature. Therefore, the turbine assembly 27 can be cooled efficiently. Mechanical flow losses are minimized.

[0040] Reference number list 0 Process medium state 1. Process medium status 2. Process medium state 3. Process medium state 4. Process medium status 5. Process Medium State 6. Process Medium State 7. Process Medium State 8. Process Medium State 9. Process Medium State 10. Process Medium State 11 Process Medium State 20 Cyclic Thermodynamic Process Systems / Heat Pump Systems 21 First heat exchanger 22. Exothermic process 23 Pressure increasing device 23a Compressor Section 23b Compressor Section 24 Second heat exchanger 25. Exothermic process 26 Pressure Reduction Device 27 Turbine Components 28 motors 29. Shell 30 branch pipelines 31 Throttling device 32 Throttling device 33 Phase Separator 34 Throttling device 35 Regenerative Heat Exchanger 36 Throttling device 37 Pressure Reduction Device 38. Drying device 39 Branch Pipelines 40 Throttling device 41 Throttling device 42 Expansion valve

Claims

1. A cyclic thermodynamic process system, particularly a heat pump system (20) or a refrigeration system, It has a first heat exchanger (21), a pressure increasing device (23), a second heat exchanger (24), and a pressure reducing device (26, 37). in, The first heat exchanger (21) is designed to heat the process medium while absorbing heat energy through it. The pressure increasing device (23) is designed to increase the pressure of the process medium downstream of the first heat exchanger (21) and upstream of the second heat exchanger (24). The second heat exchanger (24) is designed to cool the process medium while releasing heat from it. The pressure reduction devices (26, 37) are designed to reduce the pressure of the process medium downstream of the second heat exchanger (24) and upstream of the first heat exchanger (21). Its features are, The pressure increasing device (23) is part of the hermetically sealed turbine assembly (27). The hermetically sealed turbine assembly (27) includes an electric motor (28). The process medium used to cool the turbine assembly (27) may branch off downstream of the second heat exchanger (24).

2. The cyclic thermodynamic process system (20) according to claim 1, characterized in that, The process medium used to cool the turbine assembly (27) may branch off downstream of the second heat exchanger (24) and upstream of the pressure reduction devices (16, 37).

3. The cyclic thermodynamic process system (20) according to claim 1 or 2, characterized in that, The process medium used to cool the turbine assembly (27) may branch off downstream of the second heat exchanger (24) and upstream of the regenerative heat exchanger (35). On the one hand, the process medium leaving the second heat exchanger (24) flows through the regenerative heat exchanger (35), and on the other hand, the process medium leaving the first heat exchanger (21) flows through the regenerative heat exchanger (35).

4. The cyclic thermodynamic process system (20) according to claim 1, 2 or 3, characterized in that, The process medium used to cool the turbine assembly (27) may branch off directly downstream of the second heat exchanger (24).

5. The cyclic thermodynamic process system (20) according to any one of claims 1 to 4, characterized in that, A throttling device (32) is designed to expand the process medium branching off downstream of the second heat exchanger (24). A phase separator (33) is used to separate the gas phase and liquid phase of the branched and expanded process medium, wherein at least the gas phase of the branched and expanded process medium is used to cool the turbine assembly (27).

6. The cyclic thermodynamic process system (20) according to claim 5, characterized in that, The gas phase of the branched and expanded process medium is used to cool the rotor of the motor (28) of the turbine assembly (27).

7. The cyclic thermodynamic process system (20) according to claim 5 or 6, characterized in that, The liquid phase of the branched and expanded process medium is also used to cool the turbine assembly (27).

8. The cyclic thermodynamic process system (20) according to claim 7, characterized in that, The liquid phase of the branching and expanding process medium is used to cool the stator of the motor (28) of the turbine assembly (27).

9. The cyclic thermodynamic process system (20) according to any one of claims 1 to 8, characterized in that, The pressure reduction device (26, 37) includes a turbine (37). The turbine (37) is arranged together with the motor (28) and the pressure increasing device (23) in a common airtight sealed housing (29).

10. The cyclic thermodynamic process system (20) according to any one of claims 1 to 9, characterized in that, The process medium is a process medium used in supercritical cycle processes, and in particular, carbon dioxide (CO2).

11. The cyclic thermodynamic process system (20) according to any one of claims 1 to 9, characterized in that, The process medium is a process medium used in subcritical cycle processes, and in particular, propane.

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