Cyclic thermodynamic process system with cooling function for an electric machine thereof
Patent Information
- Application Number
- NZ835697
- Authority / Receiving Office
- NZ · NZ
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-04-30
- Filing Date
- 2025-04-14
- Publication Date
- 2025-11-06
AI Technical Summary
Existing thermodynamic cycle systems, such as heat pumps and refrigeration systems, face inefficiencies in operating with high efficiency, particularly due to friction losses and the need for additional power to cool the turbomachine assembly.
A hermetically sealed turbomachine assembly integrates a pressure boosting device, such as a compressor, with an electric machine, mounted via active magnetic bearings, and uses process medium diverted from the second heat exchanger to cool the assembly, minimizing friction losses and optimizing cooling efficiency.
The system operates with high efficiency by using the process medium to cool the turbomachine assembly without additional power, reducing friction losses and ensuring optimal cooling, particularly through the use of gaseous and liquid phases for efficient operation.
Smart Images
Figure 1_ABST
Abstract
Description
[0001] Thermodynamic cycle system with cooling of an electrical
[0002] machine of the same
[0003] The invention relates to a thermodynamic cycle system, in particular a heat pump system or a refrigeration system or a combination of a heat pump system or a refrigeration system.
[0004] A thermodynamic cycle system, such as a heat pump system or a refrigeration system, comprises a first heat exchanger, a pressure booster, a second heat exchanger, and a pressure reducer. The first heat exchanger is configured to heat a process medium by absorbing thermal energy from the process medium, which is supplied by a heat-emitting process. The pressure booster is configured 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 configured to cool the process medium by releasing thermal energy, which the process medium then transfers to a heat-absorbing process.The pressure reducing device is set up to reduce the pressure of the process medium downstream of the second heat exchanger and upstream of the first heat exchanger.
[0005] In a heat pump system, the heat-emitting process can also involve the environment, such as ambient air, water in a river or lake, or similar sources. Similarly, in a refrigeration system, the heat-absorbing process can also involve the environment. There is a need for a thermodynamic cycle system, particularly a heat pump or refrigeration system, that can be operated with high efficiency.
[0006] Based on this, the present invention aims to create a novel thermodynamic cycle system.
[0007] This problem is solved by a thermodynamic cycle system according to claim 1.
[0008] In the thermodynamic cycle system according to the invention, the pressure boosting device is part of a hermetically sealed turbomachine assembly, wherein the pressure boosting device is preferably designed as a compressor and has at least one single- or multi-stage compressor section for increasing the pressure of the process medium. In the thermodynamic cycle system according to the invention, the hermetically sealed turbomachine assembly includes an electric machine which, together with the pressure boosting device, is preferably arranged in a common, hermetically sealed, one- or multi-part housing and is preferably mounted in the housing via active magnetic bearings. Process medium can be diverted downstream of the second heat exchanger, which serves to cool the turbomachine assembly.
[0009] The thermodynamic cycle system according to the invention can be operated with high efficiency. The pressure booster is part of a hermetically sealed turbomachine assembly, which also includes the electric motor. Process medium can be diverted downstream of the second heat exchanger, which serves to cool the hermetically sealed turbomachine assembly, in particular the electric motor. The thermodynamic cycle system can be operated with high efficiency. The efficiency depends on the ratio of the generated heat or cooling power to the pressure booster power required by the pressure booster. No additional pressure booster power is required to provide the process medium needed to cool the turbomachine assembly.The process medium used to cool the electric machine is diverted at the lowest possible temperature, thus enabling optimal cooling of the electric machine in the hermetically sealed turbomachine arrangement.
[0010] Friction losses of the process medium in the area of the electric machine can be kept to a minimum. In the roto-stator gap of the electric machine in the hermetically sealed turbomachine assembly, the process medium used for cooling the electric machine is in the vapor phase.
[0011] Preferably, the process medium used to cool the turbomachine assembly can be branched off directly downstream of the second heat exchanger. Branching off the process medium used to cool the turbomachine assembly directly downstream of the second heat exchanger allows for particularly efficient operation of the thermodynamic cycle system.
[0012] Preferably, the thermodynamic cycle system includes a throttling device configured to expand the process medium diverted downstream of the second heat exchanger. The thermodynamic cycle system preferably also includes a phase separator to separate a gaseous phase from a liquid phase of the diverted and expanded process medium, wherein at least the gaseous phase of the diverted and expanded process medium serves to cool the turbomachine assembly, in particular to cool a rotor of the electric machine of the turbomachine assembly. Preferably, the liquid phase of the diverted and expanded process medium also serves to cool the turbomachine assembly, in particular to cool a stator of the electric machine of the turbomachine assembly.This allows for advantageous cooling of the turbomachine assembly while ensuring efficient operation of the thermodynamic cycle. At a minimum, the gaseous phase of the diverted process medium, expanded at the throttling device, is used to cool the turbomachine assembly. Optionally, the liquid phase of the diverted process medium, expanded at the throttling device, can also be used for cooling.
[0013] Preferred embodiments of the invention are set forth in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. The drawing shows:
[0014] Fig. 1a shows a first thermodynamic cycle system according to the invention used as a heat pump system;
[0015] Fig. 1b shows a pressure-enthalpy diagram of the heat pump system of Fig. 1a;
[0016] Fig. 2a shows a second thermodynamic cycle system according to the invention, used as a heat pump system;
[0017] Fig. 2b shows a pressure-enthalpy diagram of the heat pump system of Fig. 2a;
[0018] Fig. 3a shows a third thermodynamic cycle system according to the invention, used as a heat pump system;
[0019] Fig. 3b shows a pressure-enthalpy diagram of the heat pump system of Fig. 3a;
[0020] Fig. 4a shows a fourth thermodynamic cycle system according to the invention, used as a heat pump system;
[0021] Fig. 4b shows a pressure-enthalpy diagram of the heat pump system of Fig. 4a;
[0022] Fig. 5a shows a fifth thermodynamic cycle system according to the invention, used as a heat pump system; Fig. 5b shows a pressure-enthalpy diagram of the heat pump system of Fig. 5a;
[0023] Fig. 6a shows a sixth thermodynamic cycle system according to the invention, used as a heat pump system;
[0024] Fig. 6b shows a pressure-enthalpy diagram of the heat pump system of Fig. 6a;
[0025] Fig. 7a shows another thermodynamic cycle system according to the invention used as a heat pump system;
[0026] Fig. 7b shows a pressure-enthalpy diagram of the heat pump system of Fig. 7a;
[0027] The invention relates to a thermodynamic cycle system. This can be a heat pump system, a refrigeration system, or a combination of a heat pump system and a refrigeration system. The invention is described below with reference to Figures 1a to 7b, each for a heat pump system.
[0028] Fig. 1a shows a first heat pump system 20 according to the invention, Fig. 1b shows a pressure (p)-enthalpy (h) diagram belonging to the heat pump system 20.
[0029] In the pressure (p)-enthalpy (h) diagram of Fig. 1b, different states 0, 1, 2, 3, 4, 5, 6, 7 and 8 of the process medium are shown, with Fig. 1a indicating at which flow-side position in the heat pump system 20 the respective state 0, 1, 2, 3, 4, 5, 6, 7 and 8 of the process medium is present.
[0030] The heat pump system 10 of Fig. 1a has a first heat exchanger 21, which heats the process medium by absorbing thermal energy from a heat-emitting process 22. In the region of the first heat exchanger 21, the process medium therefore absorbs thermal energy and is transferred from state 5 to state 0. The heat pump system 20 also has a pressure boosting device 23, which in the embodiment of Fig. 1a is formed by two compressor sections 23a, 23b. Each of the compressor sections 23a, 23b of the pressure boosting device 23 can be designed as a single-stage or multi-stage unit and serves to increase the pressure of the process medium downstream of the first heat exchanger 21 and upstream of a second heat exchanger 24. Compressor section 23a compresses the process medium from state 1 to state 2, while compressor section 23b compresses the process medium from state 2 to state 3.
[0031] The second heat exchanger 24 is configured to cool the process medium by transferring thermal energy from the process medium to a heat-absorbing process 25. In the second heat exchanger 24, the process medium is transferred from state 3 to state 4.
[0032] The heat pump system 20 of Fig. 1a further includes a pressure reducing device 26, which in the embodiment of Fig. 1a is an expansion valve that expands the process medium from state 4 to state 5.
[0033] The pressure boosting device 23 with its two compressor sections 23a, 23b is part of a hermetically sealed turbomachine assembly 27. An electric machine 28 is also part of this hermetically sealed turbomachine assembly 27. The pressure boosting device 23 and the electric machine 28 are arranged in a common, hermetically sealed, one- or multi-part housing 29 of the hermetically sealed turbomachine assembly 27, the housing 29 being shown in dashed lines in Fig. 1a. The pressure boosting device 23, namely its compressor sections 23a, 23b, and the electric machine 28 are preferably mounted in the housing 29 via active magnetic bearings (not shown).The coolant required for cooling the hermetically sealed turbomachine assembly 27 is provided by diverting process medium from the closed heat pump circuit via a branch line 30 downstream of the second heat exchanger 24 and supplying it to the turbomachine assembly 27 for cooling via a supply line 31. A throttling device 32 is integrated into the branch line 30, which expands the process medium diverted for cooling, starting from state 4. In state 4, the process medium is liquid, which is partially converted into a gaseous phase and partially into a liquid phase by the throttling device 32. The gaseous phase is in state 6 and the liquid phase in state 7.
[0034] The gaseous phase is separated from the liquid phase in a phase separator 33. The supply line 31 carries the gaseous phase from the phase separator 33 to the hermetically sealed turbomachine assembly 27 for cooling. The liquid phase can be mixed from the phase separator 33 with the process medium, which has expanded in the region of the throttle valve 26, and subsequently reheated by the first heat exchanger 21.
[0035] In the pressure (p)-enthalpy (h) diagram of Fig. 1b, state 7 lies on a liquid saturation line I, while states 0 and 6 lie on a 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 it exists in vapor-liquid equilibrium.
[0036] To the left of the liquid saturation line I in region IV lies a supercooled liquid phase, and to the right of the vapor saturation line II in region V, a superheated vapor phase is present. Above a critical point VI, the process medium is in a supercritical state. The heat pump system 10 of Fig. 1a, in which the pressure booster 23 and the electric motor 28 are part of the hermetically sealed turbomachine assembly 27, can be operated with high efficiency. Refrigerant is diverted from the closed heat pump circuit directly downstream of the second heat exchanger 24 to cool the turbomachine assembly 27. In the embodiment of Fig. 1a, only the gaseous phase of the diverted and expanded process medium is used to cool the hermetically sealed turbomachine assembly 27, namely the electric motor 28.For this purpose, the gaseous phase is fed into the turbomachine assembly in state 6. Through engine loss absorption, the process medium is heated to state 8. Subsequently, the process medium of state 8, diverted for cooling, is mixed with the process medium of the main circuit in state 0 to achieve process medium of state 1, whereby the process medium of state 1 is fed towards the compressor section 23a for compression.
[0037] Fig. 1a shows a further throttling device 34 to reduce the liquid phase of the liquid process medium discharged from the phase separator 33 from state 7 to state 5.
[0038] Fig. 2a shows a further development of the heat pump system 20 of Fig. 1a, Fig. 2b shows the corresponding pressure (p)-enthalpy (h) diagram. The heat pump system 20 of Fig. 1a and the heat pump system 20 of Fig. 2a differ only in that the heat pump system 20 of Fig. 2a additionally includes a recuperator heat exchanger 35, through which the process medium leaving the second heat exchanger 24 and the process medium leaving the first heat exchanger 21 flow for the recuperation of thermal energy. Via the branch line 30, process medium is again diverted directly downstream of the second heat exchanger 24 from the closed heat pump circuit and guided via the throttling device 32 towards the phase separator 33, whereby in Fig. 2a the gaseous phase is again supplied via the supply line 31 to the turbomachine arrangement 27 for cooling.Due to the fact that the heat pump system 20 of Fig. 2a additionally has the recuperator heat exchanger 35, the heat pump systems also differ with regard to the states of the process medium, whereby in Fig. 2b and Fig. 2a the respective states 1 to 10 of the process medium are shown in the pressure (p)-enthalpy (h) diagram as well as in the area of the respective components of the process medium in which the states occur.
[0039] As already explained, in the heat pump system 20 of Fig. 2a, the process medium used as coolant for the hermetically sealed turbomachine arrangement 27 is also diverted directly downstream of the second heat exchanger 24 from the heat pump circuit, namely upstream of the recuperator heat exchanger 35.
[0040] Fig. 3a shows a modification of the heat pump system 20 of Fig. 2a, which differs from the heat pump system 20 of Fig. 2a in that, in the heat pump system 20 of Fig. 3a, not only the gaseous phase from the phase separator 33 of the hermetically sealed turbomachine assembly 27 is supplied via the supply line 31 for cooling, but also the liquid phase via a separate supply line 36. The gaseous phase is used in particular for cooling a rotor of the electric machine 28 of the hermetically sealed turbomachine assembly 27, and the liquid phase in particular for cooling a stator of the electric machine 28. Fig. 3b shows the pressure (p)-enthalpy (h) diagram for the heat pump system 20 of Fig. 3a with the states of the process medium. The heat pump systems 20 of Fig. 1a, 2a and 3a are particularly suitable for use in a subcritical cycle process, especially when using propane as the process medium.However, they can also be used in a supercritical cycle, especially when using CO2 as the process medium.
[0041] Fig. 4a shows a modification of the heat pump system 20 of Fig. 2a. The heat pump system 20 of Fig. 4a differs from the heat pump system 20 of Fig. 2a in that, in Fig. 4a, the hermetically sealed turbomachine assembly 27, in addition to the pressure boosting device 23 and the electric machine 28, includes a turbine 37 as a further assembly, which, together with the expansion valve 26 and an optional further expansion valve 42, forms the pressure reducing device. This turbine 37, together with the electric machine 28 and the compressor 23, is arranged in the hermetically sealed housing 29 of the turbomachine assembly 27 and is preferably mounted there via active magnetic bearings. Also in Fig.4a can be branched off from the closed heat pump circuit process medium via the branch line 30 and fed to the phase separator 33 via the throttling device 32. From the phase separator 33, the gaseous phase is conveyed via the supply line 31 towards the hermetically sealed turbomachine assembly 27 for cooling, but unlike in Fig. 2a, it is guided through an additional drying device 38. Such a drying device 38 is used in particular when the process medium contains moisture or is wet after further pressure reduction. Thermal energy required in the drying device 38 to dry the gaseous phase, which is conveyed from the phase separator 31 towards the turbomachine assembly 27, can be recuperated from the refrigerant already conveyed via the electric machine 28 in the area of the drying device 38. In Fig.Figure 4b again shows the states of the process medium for the heat pump system 20 of Figure 4a, with states 3, 4, and 5 lying in the supercritical region VII of the pressure (p)-enthalpy (h) diagram of Figure 4b. Figure 5a shows a modification of the heat pump system 20 of Figure 4a, in which, starting from the phase separator 33, the liquid phase of the process medium used to cool the turbomachine assembly 27 is also directed towards the hermetically sealed turbomachine assembly, in particular to cool the rotor of the electric machine 28 via the gaseous phase and the stator of the electric machine 28 via the liquid phase, in accordance with the embodiment of Figure 3a. The corresponding states of the process medium are again shown in the pressure (p)-enthalpy (h) diagram of Figure 5b.
[0042] Another heat pump system 20 according to the invention is shown in Fig. 6a, wherein the heat pump system 20 of Fig. 6a is a further development of the heat pump system 20 of Fig. 1a and, in accordance with the embodiment of Fig. 1a, comprises the two compressor sections 23a, 23b, which together with the electric machine 28 are arranged in the housing 29 of the hermetically sealed turbomachine arrangement 27.
[0043] In the heat pump system 20 of Fig. 6a, immediately downstream of the second heat exchanger 24, refrigerant serving to cool the turbomachine assembly 27 is diverted from the closed heat pump circuit via the branch line 30. Furthermore, a portion of the process medium leaving the second heat exchanger 24 is routed via a further branch line 39 towards the compressor section 23, where it is compressed together with the process medium leaving the compressor section 23a in the area of the compressor section 23b. The throttle valve 40 serves to equalize the pressure of the process medium. The states of the process medium for the heat pump system 20 of Fig. 6a are shown in the pressure (p)-enthalpy (h) diagram of Fig. 6b.
[0044] Fig. 7a shows a further development of the heat pump system 20 of Fig. 6a, wherein the heat pump system of Fig. 7a differs from the heat pump system of Fig. 6a in that, unlike Fig. 6a, not only the gaseous phase but also the liquid phase of the process medium branched off via the branch line 30 is used to cool the hermetically sealed turbomachine arrangement 27. The corresponding states of the process medium for the heat pump system 20 of Fig. 7a are shown in the pressure (p)-enthalpy (h) diagram of Fig. 7b.
[0045] All of the heat pump systems 20 shown have in common that the heat pump system 20 comprises a hermetically sealed turbomachine assembly 27, which includes at least the pressure boosting device 23 and the electric machine 28. For cooling the turbomachine assembly 27, refrigerant is diverted from the closed heat pump circuit via a branch line 30 directly downstream of the second heat exchanger 24, whereby at least the gaseous phase and optionally also the liquid phase of the diverted and expanded process medium is used for cooling the hermetically sealed turbomachine assembly 27.
[0046] The invention enables the efficient operation of a heat pump system 20. The process medium used to cool the turbomachine assembly 27, which is branched off from the closed heat pump circuit directly downstream of the second heat exchanger 24, has a low temperature. This allows the turbomachine assembly 27 to be cooled efficiently. Mechanical flow losses are minimized.
[0047] Reference symbol list
[0048] 0 Process medium state
[0049] 1 Process medium state
[0050] 2 Process medium state
[0051] 3 Process medium state
[0052] 4 Process medium condition
[0053] 5 Process medium condition
[0054] 6 Process medium state
[0055] 7 Process medium state
[0056] 8 Process medium condition
[0057] 9 Process medium state
[0058] 10 Process medium state
[0059] 11 Process medium state
[0060] 20 thermodynamic cycle system / heat pump system
[0061] 21 first heat exchanger
[0062] 22 heat-emitting process
[0063] 23 Pressure boosting device
[0064] 23a Grain pressor section
[0065] 23b grain pressor section
[0066] 24 second heat exchanger
[0067] 25 heat-emitting process
[0068] 26 Pressure reducing device
[0069] 27 Turbomachine arrangement
[0070] 28 electric machine
[0071] 29 cases
[0072] 30 branch line
[0073] 31 Throttle device
[0074] 32 Throttle device
[0075] 33 phase separators
[0076] 34 Throttle device
[0077] 35 Recuperator heat exchanger 36 Throttle device
[0078] 37 Pressure reducing device
[0079] 38 Drying equipment
[0080] 39 Branch line 40 Throttle device
[0081] 41 Throttle device
[0082] 42 Expansion valve
Claims
Claims 1. Thermodynamic cycle system, in particular heat pump system (20) or refrigeration system, comprising a first heat exchanger (21), a pressure booster (23), a second heat exchanger (24), and a pressure reducer (26, 37), wherein the first heat exchanger (21) is configured to heat a process medium by absorbing thermal energy through the process medium, wherein the pressure booster (23) is configured to increase the pressure of the process medium downstream of the first heat exchanger (21) and upstream of the second heat exchanger (24), wherein the second heat exchanger (24) is configured to cool the process medium by releasing thermal energy from the process medium, and wherein the pressure reducer (26, 37) is configured to reduce the pressure of the process medium downstream of the second heat exchanger (24) and upstream of the first heat exchanger (21), characterized in thatthat the pressure boosting device (23) is part of a hermetically sealed turbomachine arrangement (27), the hermetically sealed turbomachine arrangement (27) includes an electric machine (28), and process medium can be branched off downstream of the second heat exchanger (24), which serves to cool the turbomachine arrangement (27).
2. Thermodynamic cycle system (20) according to claim 1 , characterized in that the process medium which serves to cool the turbomachine arrangement (27) can be branched off downstream of the second heat exchanger (24) and upstream of the pressure reducing device (16, 37).
3. Thermodynamic cycle system (20) according to claim 1 or 2, characterized in that the process medium, which serves to cool the turbomachine arrangement (27), can be branched off downstream of the second heat exchanger (24) and upstream of a recuperator heat exchanger (35), through which on the one hand the process medium leaving the second heat exchanger (24) and on the other hand the process medium leaving the first heat exchanger (21) flows.
4. Thermodynamic cycle system (20) according to claim 1, 2 or 3, characterized in that the process medium which serves to cool the turbomachine arrangement (27) can be branched off directly downstream of the second heat exchanger (24).
5. Thermodynamic cycle system (20) according to one of claims 1 to 4, characterized by a throttling device (32) configured to expand the process medium diverted downstream of the second heat exchanger (24), a phase separator (33) to separate a gaseous phase from a liquid phase of the diverted and expanded process medium, wherein at least the gaseous phase of the diverted and expanded process medium serves to cool the turbomachine arrangement (27).
6. Thermodynamic cycle system (20) according to claim 5, characterized in that the gaseous phase of the diverted and expanded process medium serves to cool a rotor of the electric machine (28) of the turbomachine arrangement (27).
7. Thermodynamic cycle system (20) according to claim 5 or 6, characterized in that the liquid phase of the diverted and expanded process medium also serves to cool the turbomachine arrangement (27).
8. Thermodynamic cycle system (20) according to claim 7, characterized in that the liquid phase of the diverted and expanded process medium serves to cool a stator of the electrical machine (28) of the turbomachine arrangement (27).
9. Thermodynamic cycle system (20) according to one of claims 1 to 8, characterized in that the pressure reducing device (26, 37) has a turbine (37), the turbine (37) together with the electric machine (28) and the pressure increasing device (23) is arranged in the common, hermetically sealed housing (29).
10. Thermodynamic cycle process system (20) according to one of claims 1 to 9, characterized in that the process medium is a process medium for a supercritical cycle process, in particular carbon dioxide CO2.
11. Thermodynamic cycle process system (20) according to one of claims 1 to 9, characterized in that the process medium is a process medium for a subcritical cycle process, in particular propane.