Triangular circulation system

Abstract

A triangular cycle system (10) includes an expander (14) driven by a working fluid of gas-liquid two-phase flow supplied from a heat exchanger (13), and a generator (16) coupled to the expander (14), in which the generator (16) is disposed at a position midway of a passage (19) through which the working fluid of gas-liquid two-phase flow flows between the heat exchanger (13) and the expander (14), and a cooling passage (21) for cooling the generator (16) is constituted by a part of the passage (19).

Description

Technical Field

[0001] The present invention relates to a trilateral cycle system, and more specifically, to a trilateral cycle system comprising an expander and a generator, the expander being driven by a working fluid of gas-liquid two-phase flow supplied from a heat exchanger, the generator being connected to the expander. Background Technology

[0002] A Rankine cycle system has been proposed, which, although not a triangular cycle system, houses the expander and generator within a sealed container. The internal space of the sealed container, containing the generator, is formed by a portion of the flow path between the pump and the heater (heat exchanger) (see, for example, Patent Document 1). The Rankine cycle system described in Patent Document 1 suppresses the temperature rise of the generator by cooling it with the working fluid before it is heated by the heater, and preheats the working fluid flowing into the heater.

[0003] Prior technology documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2009-174494 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] In addition, a triangular circulation system is known, which, in heat recovery, acts as a system for recovering energy from a low-temperature heat source, forming an approximate triangle in the temperature-entropy diagram. The triangular circulation, also known as a gas-liquid two-phase adiabatic expansion cycle, refers to a cycle in which, after heat exchange from the heat source to the working fluid, the working fluid becomes a gas-liquid two-phase state. Within the expander, the gas-liquid two-phase working fluid is depressurized and boiled, thereby extracting energy.

[0008] Even if the invention described in Patent Document 1 is applied to a triangular circulation system, it is still a structure used to cool the generator with the working fluid before it is heated by the heater. Therefore, inside a sealed container, there will be working fluids with different temperature zones. Thus, even if the invention described in Patent Document 1 is applied to a triangular circulation system, the high-temperature working fluid will be cooled, or the low-temperature working fluid will be heated, making insulation measures necessary and complicating the internal structure of the sealed container. Furthermore, because it is a structure connecting two flow paths in a sealed container, it restricts the flow paths of the system. Therefore, even if the technical aspects of the Rankine cycle system are simply applied to a triangular circulation system, it is impossible to simultaneously achieve generator cooling and heat recovery from the generator with a simple configuration.

[0009] The inventors of this application focused on the case where the working fluid supplied from the heat exchanger to the expander in a triangular cycle is in a gas-liquid two-phase state, and discovered the use of a working fluid that is a gas-liquid two-phase flow flowing into the expander.

[0010] The purpose of this disclosure is to provide a triangular circulation system that simultaneously achieves generator cooling and heat recovery from generator exhaust by utilizing a gas-liquid two-phase flow working fluid.

[0011] Technical means for solving technical problems

[0012] A triangular circulation system of the present invention, which achieves the above-mentioned objective, is characterized by comprising an expander and a generator, the expander being driven by a working fluid of gas-liquid two-phase flow supplied from a heat exchanger, the generator being connected to the expander; in the triangular circulation system, the generator is positioned midway through a channel for the gas-liquid two-phase flow of the working fluid between the heat exchanger and the expander, and a cooling channel for cooling the generator is formed by a portion of the channel.

[0013] Invention Effects

[0014] According to one aspect of the present invention, when the working fluid of the gas-liquid two-phase flow flows in the cooling channel, the liquid phase of the working fluid evaporates due to the heat of the generator, thereby cooling the generator and recovering the heat dissipation of the generator. Attached Figure Description

[0015] Figure 1 This is a diagram illustrating the configuration of a triangular circulation system in an illustrative implementation.

[0016] Figure 2 This is an example Figure 1 A cross-sectional view of the interior of the shell.

[0017] Figure 3 This is an example Figure 1 A cross-sectional view of the interior of the first deformed example of the shell.

[0018] Figure 4 This is an example Figure 1 A cross-sectional view of the interior of the second modified example of the shell.

[0019] Figure 5 This is an example Figure 1 A cross-sectional view of the interior of the third modified example of the shell. Detailed Implementation

[0020] The following describes an embodiment of the triangular circulation system of this disclosure. In the figures, hollow arrows indicate heat dissipation flow, and black arrows indicate working fluid flow. The dimensions of the components are varied in the figures to make the configuration easy to understand, but are not intended to be consistent with actual manufacturing. Hereinafter, in this disclosure, "channel" refers to a part through which the working fluid flows, and "piping" refers to the components constituting the channel.

[0021] like Figure 1 As illustrated, the triangular circulation system 10 of this embodiment is a system that converts and recovers the exhaust heat from an engine (not shown) into electricity. Cooling water is exemplified as the engine's exhaust heat, cooling the exhaust gas generated by fuel combustion and the heat released during combustion. Even when the working fluid flowing into the expander 14 is not dry steam but a gas-liquid two-phase state, and the engine's exhaust heat is at a low temperature of 100°C or below, the triangular circulation system 10 can recover the exhaust heat. Therefore, engine cooling water is preferably used as the heat source for the triangular circulation system 10, and this embodiment uses cooling water as the exhaust heat in the triangular circulation system 10. Ethanol is exemplified as the working fluid for the triangular circulation system 10.

[0022] Regarding the triangular circulation system 10, a pump 12, a heat exchanger 13, an expander 14, and a condenser 15 are sequentially arranged in relation to the flow of the working fluid in the circulation channel 11. The triangular circulation system 10 includes a generator 16, which is connected to the expander 14.

[0023] The working fluid circulating in the circulation channel 11 via pump 12 exchanges heat with the engine's cooling water in the heat exchanger 13 and is heated, becoming a gas-liquid two-phase working fluid. The gas-liquid two-phase working fluid after passing through the heat exchanger 13 drives the expander 14. The working fluid driving the expander 14 is cooled by the condenser 15 and returns to pump 12. Driven by the expander 14, the electricity generated by the generator 16 is stored in a battery (not shown).

[0024] The triangular circulation system 10 is configured to include a housing 20 and a cooling channel 21. The triangular circulation system 10 has the following structure: an expander 14 and a generator 16 are housed inside a housing 20. Inside the housing 20, the output shaft 17 of the expander 14 and the drive shaft 18 of the generator 16 are coaxially arranged and directly connected. The triangular circulation system 10 exists between a heat exchanger 13 and an expander 14 in a circulation channel 11. The generator 16 is positioned midway through a channel 19 through which the working fluid (gas-liquid two-phase flow) from the heat exchanger 13 flows. The cooling channel 21, which cools the generator 16, is formed by a portion of the channel 19. In the figure, the shaded portion represents the channel 19.

[0025] exist Figure 2 In this context, the X direction represents the axial direction of the output shaft 17 and the drive shaft 18, and the Y direction represents the direction orthogonal to the X direction. In this disclosure, the front end and the end end are based on the flow of the working fluid; the front end represents the end existing on the upstream side, and the end end represents the end existing on the downstream side.

[0026] like Figure 2 As illustrated, the expander 14 is configured to include: a fluid device 14a that converts the energy of a gas-liquid two-phase working fluid into rotational motion of an output shaft 17; and an expander housing 14b that houses the fluid device 14a. The fluid device 14a can be a turbine type (centrifugal turbine or axial turbine) or a positive displacement type (blade expander, vortex expander, screw expander), and is not particularly limited thereto. The expander 14 of this embodiment employs a rotary expander, in which the fluid device 14a has the following structure: an impeller slides on the outer or inner circumferential surface of a piston.

[0027] The generator 16 is configured to have: a rotor 16a, which is fixed to a drive shaft 18; and a stator 16b, which is disposed around the rotor 16a and fixed to a housing 20. The generator 16 is electrically connected to a battery via an inverter (not shown). The generator 16 has a cooling channel 21 formed inside it for cooling the generator 16.

[0028] The casing 20 forms a closed structure, housing the generator 16 on the upstream side and the expander 14 on the downstream side for the flow of the gas-liquid two-phase working fluid. The casing 20 is connected to an inlet pipe 22 and an outlet pipe 23.

[0029] Inlet pipe 22, one of the pipes constituting channel 19, is the pipe through which the working fluid, in a two-phase flow from the heat exchanger 13, flows into the interior of the housing 20. The end of inlet pipe 22 is located inside the housing 20. Outlet pipe 23 is the pipe through which the working fluid, having passed through the expander 14, flows out of the housing 20.

[0030] Cooling passage 21 is part of passage 19 and is a passage that connects to inlet piping 22 at its front end, passes through generator 16 in the middle, and connects to inlet 14c of fluid device 14a of expander 14 at its end. Cooling passage 21 is a passage for the flow of working fluid in a gas-liquid two-phase flow, and in relation to the flow of its working fluid, it is provided with drive shaft passage 24, output shaft passage 25, and connecting passage 26 in sequence from the upstream side.

[0031] The drive shaft channel 24 is a channel formed inside the drive shaft 18 for the flow of the working fluid in a two-phase flow of gas and liquid. The front end of the drive shaft channel 24 is connected to the inlet pipe 22, and the end end is connected to the output shaft channel 25. The drive shaft 18, with the drive shaft channel 24 formed inside, is composed of piping, and a rotor 16a is fixed to the outer circumferential surface of this piping.

[0032] The output shaft channel 25 is a channel formed inside the output shaft 17 for the flow of the working fluid in a two-phase gas-liquid flow after passing through the drive shaft channel 24. The front end of the output shaft channel 25 communicates with the drive shaft channel 24, and the rear end communicates with the connecting channel 26. The output shaft 17, with the output shaft channel 25 formed inside, is constructed of piping driven by the fluid device 14a.

[0033] The connecting channel 26 is a channel formed in the expander housing 14b for the flow of the working fluid in a two-phase gas-liquid flow after passing through the output shaft channel 25. The front end of the connecting channel 26 is connected to the output shaft channel 25, and the end end is connected to the inlet 14c of the fluid device 14a.

[0034] The outer diameter of the drive shaft 18 is less than the inner diameter of the inlet pipe 22. The front end of the drive shaft 18 is disposed inside the inlet pipe 22. The drive shaft 18 is rotatably connected to the inlet pipe 22 via a channel 24. Preferably, the outer diameter of the drive shaft 18 is smaller than the inner diameter of the inlet pipe 22. When the outer diameter of the drive shaft 18 becomes smaller than the inner diameter of the inlet pipe 22, the outer circumferential surface of the drive shaft 18 becomes "non-contact" relative to the inner circumferential surface of the inlet pipe 22, which is beneficial for reducing the resistance load caused by contact. When the outer diameter of the drive shaft 18 becomes smaller than the inner diameter of the inlet pipe 22, a gap is created between the outer circumferential surface of the drive shaft 18 and the inner circumferential surface of the inlet pipe 22. The outlet of the expander 14 is at a lower pressure than the interior of the housing 20, so the working fluid of the gas-liquid two-phase flow flows from the inlet pipe 22 to the drive shaft 18 without leaking out through this gap. Even if the working fluid of the gas-liquid two-phase flow leaks out from the gap, it will remain inside the housing 20 and will not be exposed to the outside of the housing 20.

[0035] The outer diameter of the piping of the output shaft 17 is the same as the inner diameter of the piping of the drive shaft 18. The front end of the output shaft 17 is disposed inside the drive shaft 18. The outer circumferential surface of the output shaft 17 is fixed to the inner circumferential surface of the drive shaft 18. Preferably, the front end of the output shaft 17 extends to the central portion of the generator 16. Since the front end of the output shaft 17 is located in the central portion of the generator 16, the fixed area of ​​the output shaft 17 and the drive shaft 18 is increased, which is beneficial for fixing the rotating piping to each other. To increase the fixed area of ​​the output shaft 17 and the drive shaft 18, the front end of the output shaft 17 may also be disposed upstream of the central portion of the generator 16 in relation to the flow of the working fluid. Alternatively, the end of the drive shaft 18 may protrude from the generator 16 toward the expander 14.

[0036] A through hole 26a is formed on the upper side of the channel wall at the end of the connecting channel 26 in the X direction, and the through hole 26a extends through the channel in the X direction. The diameter of the through hole 26a is greater than or equal to the outer diameter of the piping of the output shaft 17. The end of the output shaft 17 protrudes downward in the X direction from the fluid device 14a and is disposed inside the end of the connecting channel 26 via the through hole 26a. The output shaft 17 is rotatably connected to the connecting channel 26 via a channel 25. Preferably, the diameter of the through hole 26a is larger than the outer diameter of the piping of the output shaft 17. When the diameter of the through hole 26a becomes larger than the outer diameter of the piping of the output shaft 17, the outer peripheral surface of the output shaft 17 becomes "non-contact" relative to the expander housing 14b, which is beneficial for reducing the resistance load caused by contact. Similarly, preferably, the diameter of the through hole 14d is also greater than the outer diameter of the pipe of the output shaft 17. The through hole 14d is formed at the upper part of the expander housing 14b in the X direction so that the output shaft 17 can be inserted through it, and its diameter is greater than the outer diameter of the pipe of the output shaft 17.

[0037] The working fluid in the gas-liquid two-phase flow that passes through heat exchanger 13 flows in the following order: inlet pipe 22, drive shaft channel 24, output shaft channel 25, connecting channel 26, fluid device 14a, and outlet pipe 23. When passing through drive shaft channel 24, if the temperature of generator 16 is higher than the temperature of the working fluid in the gas-liquid two-phase flow, the liquid phase of the working fluid evaporates, and in the process of evaporation, it removes heat of vaporization from generator 16. As a result, generator 16 is cooled, and the working fluid in the gas-liquid two-phase flow recovers the heat discharged from generator 16.

[0038] As described above, in the triangular circulation system 10 of this embodiment, the cooling channel 21 for cooling the generator 16 is a portion of channel 19, through which the working fluid in a gas-liquid two-phase flow passes from the heat exchanger 13. Therefore, according to the triangular circulation system 10, when the working fluid in the gas-liquid two-phase flow flows in the cooling channel 21, the liquid phase of the working fluid evaporates due to the heat of the generator 16, thereby enabling the recovery of the generator 16's exhaust heat simultaneously with cooling the generator 16.

[0039] The technique of cooling a generator or electric generator mounted in a vehicle using engine coolant is a known and conventional technique. In this embodiment, the triangular circulation system 10 uses the engine's coolant for engine heat dissipation. Therefore, if the temperature of the working fluid flowing into the expander 14 is lower than the engine's coolant temperature, and the generator 16 is a generator or electric generator within the scope of known and conventional techniques, then it is adequately cooled. Furthermore, the specifications of the generator 16 in this embodiment can be appropriately modified.

[0040] Preferably, in the triangular circulation system 10, the expander 14 and the generator 16 are housed within a single housing 20. By housing the expander 14 and the generator 16 within a single housing 20, as in this embodiment, even if working fluid leaks from the output shaft 17 of the expander 14, the leaked working fluid will remain inside the housing 20, preventing it from flowing out. This reduces the frequency of periodic maintenance due to working fluid leakage.

[0041] Preferably, in the triangular circulation system 10, the output shaft 17 of the expander 14 and the drive shaft 18 of the generator 16 are arranged coaxially, and a channel for the working fluid of gas-liquid two-phase flow is formed inside each of these shafts. When the output shaft 17 and the drive shaft 18 are both constructed by piping with shaft channels formed inside, as in this embodiment, it is not necessary to separately install piping for forming the cooling channel 21. Therefore, the integrated structure in which the expander 14 and the generator 16 are housed inside a single housing 20 can be made compact.

[0042] The above describes the embodiments of this disclosure, but the triangular circulation system 10 of this disclosure is not limited to a specific embodiment and can be modified and altered in various ways within the scope of the spirit of this disclosure.

[0043] like Figure 3As illustrated, in the case where the output shaft 17 of the expander 14 and the drive shaft 18 of the generator 16 are configured to be coaxially aligned and interconnected, the triangular circulation system 10 can also be configured such that the output shaft 17 is connected to the connecting channel 26 at a midpoint. In the output shaft 17, a solid shaft 17a and a hollow shaft 17b, which is constructed of piping, are coaxially aligned, with the end of the hollow shaft 17b disposed inside the connecting channel 26. The end of the drive shaft 18 is also disposed inside the connecting channel 26. Multiple through holes 27 are formed on the pipe walls where the two pipes overlap at the ends of the hollow shaft 17b and the drive shaft 18. Preferably, by making the ends of the hollow shaft 17b and the drive shaft 18 overlap inside the connecting channel 26 to form a double layer, the durability reduced by the formation of multiple through holes 27 at their ends is improved.

[0044] like Figure 4 As illustrated, in the case of the triangular circulation system 10, where the expander 14 and the generator 16 are connected by an output / drive shaft 28, a shaft channel 29 is formed inside the output / drive shaft 28, which is constructed of piping. Regarding this output / drive shaft 28, a rotor 16a is fixed to the upper portion in the X direction, and a fluid device 14a is fixed to the lower portion in the X direction.

[0045] In addition, such as Figure 5 As illustrated, it can also be configured as follows: the output / drive shaft 28 consists of a solid output shaft portion 28a and a hollow drive shaft portion 28b in which the output shaft portion 28a is disposed at the center of the shaft, and the output shaft portion 28a and the drive shaft portion 28b are connected by a connecting portion 28c. Regarding this output / drive shaft 28, the fluid device 14a of the expander 14 is fixed to the output shaft portion 28a, and the rotor 16a of the generator 16 is fixed to the drive shaft portion 28b. With this output / drive shaft 28, regarding the cooling channel 21, the end of the output / drive shaft 28 is directly connected to the inlet 14c of the fluid device 14a of the expander 14.

[0046] As described above, the connection between the expander 14 and the generator 16 and the configuration of the cooling passage 21 can be appropriately modified according to the specifications of the fluid equipment 14a of the expander 14 and the durability of each piping.

[0047] The triangular circulation system 10 disclosed herein is not limited to an integrated structure in which the expander 14 and the generator 16 are housed inside a housing 20, but can also be configured to be separately arranged on the circulation channel 11 of the triangular circulation system 10.

[0048] Furthermore, the triangular circulation system 10 disclosed herein is not limited to a configuration in which cooling channels 21 are formed inside the output shaft 17 of the expander 14 and the drive shaft 18 of the generator 16, but may also be a configuration in which their shafts and cooling channels 21 are separately configured.

[0049] This application is based on Japanese Patent Application No. 2021-046805, filed on March 22, 2021, the contents of which are incorporated herein by reference.

[0050] Industrial availability

[0051] This disclosure has the effect that, as the working fluid in the gas-liquid two-phase flow flows in the cooling channel, the liquid phase of the working fluid evaporates due to the heat of the generator, thus enabling the recovery of the generator's exhaust heat while simultaneously cooling the generator, which is useful for systems such as triangular circulation systems.

[0052] Explanation of reference numerals in the attached figures

[0053] 10. Triangular circulation system

[0054] 11 Circulation Channel

[0055] 12 pumps

[0056] 13 Heat Exchangers

[0057] 14 Expander

[0058] 15 Condenser

[0059] 16 Generators

[0060] 17 Output shaft

[0061] 18 drive shafts

[0062] 19 channels

[0063] 20. Housing

[0064] 21 Cooling Channels

Claims

1. A triangular circulation system, characterized in that, It includes an expander and a generator with a drive shaft, the expander being driven by a working fluid of gas-liquid two-phase flow supplied from a heat exchanger, and the generator being connected to the expander; In this triangular circulation system, The generator is positioned midway through the channel through which the working fluid, which supplies a two-phase flow of gas and liquid, passes between the heat exchanger and the expander. The cooling channel that cools the generator is formed by a portion of the channel. The drive shaft uses the driving force transmitted from the expander to drive the generator. The working fluid, which is a gas-liquid two-phase flow, cools the generator by passing through the interior of the drive shaft.

2. The triangular circulation system as described in claim 1, wherein, The expander and the generator are housed inside a single casing.

3. The triangular circulation system as described in claim 2, wherein, The housing is formed by connecting an inlet pipe and an outlet pipe. The inlet pipe allows the working fluid, which is a gas-liquid two-phase flow after passing through the heat exchanger, to flow in, and the outlet pipe allows the working fluid, which is a gas-liquid two-phase flow after passing through the expander, to flow out. The cooling channel is configured as follows: its front end is connected to the inlet pipe of the housing, its middle section passes through the generator, and its end is connected to the inlet of the expander.

4. The triangular circulation system as described in claim 3, wherein, The output shaft of the expander and the drive shaft of the generator are configured on the same axis and connected to each other. Inside the output shaft and the drive shaft, a shaft channel is formed for the flow of the working fluid in a two-phase gas-liquid flow. The output shaft and the drive shaft are respectively composed of piping. The cooling channel is configured to have the shaft channel and a connecting channel that connects the outlet of the shaft channel to the inlet of the fluid equipment of the expander.

5. The triangular circulation system as described in claim 4, wherein, Shaft channels are formed inside both the output shaft and the drive shaft, and the output shaft and the drive shaft are respectively composed of pipes; The outer diameter of the output shaft pipe is the same as the inner diameter of the drive shaft pipe. The front end of the output shaft is disposed inside the drive shaft, and the outer peripheral surface of the output shaft is fixed to the inner peripheral surface of the drive shaft.

6. The triangular circulation system as described in claim 4 or 5, wherein, Regarding the inlet piping, its end is disposed inside the housing; The outer diameter of the drive shaft piping is less than or equal to the inner diameter of the inlet piping. The front end of the drive shaft is disposed inside the inlet piping; The shaft channel formed inside the drive shaft is rotatable and communicates with the interior of the inlet pipe.

7. The triangular circulation system as described in claim 3, wherein, The expander and the generator are connected by an output and drive shaft; Inside the output and drive shaft, a shaft channel is formed for the flow of the working fluid, which is a two-phase flow of gas and liquid. The output and drive shaft is constructed of piping.

8. The triangular circulation system as described in claim 7, wherein, The cooling channel has only the shaft channel and is connected to the inlet of the fluid equipment of the expander.

9. The triangular circulation system as described in claim 7, wherein, The cooling channel is configured to have the shaft channel and a connecting channel, the connecting channel connecting the outlet of the shaft channel and the inlet of the fluid equipment of the expander.

Images