Pump type heat storage battery

Abstract

To provide a pump type heat storage battery capable of driving with further high efficiency.SOLUTION: A pump type heat storage battery has a compressor, a turbine, a first channel connecting a discharge side of the compressor and an entrance side of the turbine, a heat storage tank, a second channel connecting an exhaust side of the turbine and an entrance side of the compressor, a cold storage tank, a motor coaxially connected to the compressor, a generator coaxially connected to the turbine, a switchover part for controlling a flow direction of working fluid, and a rotational frequency adjustment part for independently adjusting rotational frequencies of the compressor and the turbine. The switchover part switches a charging state where the working fluid discharged from the compressor flows into the entrance side of the turbine through the heat storage tank and flows into the entrance side of the compressor through the cold storage tank after driving the turbine over to a generation state where the working fluid discharged from the compressor drives the turbine and the generator in a state of high temperature and high pressure through the heat storage tank and flows into the entrance side of the compressor through the cold storage tank.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a pumped heat storage battery. [Background technology]

[0002] As an example of an efficient power generation plant, the one described in the following Patent Document 1 and a pump-type heat storage battery are expected to be put into practical use. The pump-type heat storage battery mainly includes a motor, two compressors, two turbines, a heat storage tank, and a cold storage tank. In a charging state, the motor drives the compressor to generate high-temperature, high-pressure air, and the heat of this air is stored in the heat storage tank. After that, the air that has passed through the heat storage tank is used to drive the turbine, and expands, becoming a low-temperature state. This low-temperature air passes through the cold storage tank, and cold heat is stored in the cold storage tank. On the other hand, in a power generation state, the power generation compressor is driven to generate high-pressure air, and then the air is passed through the heat storage tank to further increase the temperature and pressure of the air. The high-temperature, high-pressure air drives a power generation turbine, and electricity can be generated by a generator connected to the shaft end. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-242694 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional pump-type thermal storage batteries, two compressors and two turbines are required as described above, which increases construction and maintenance costs. Furthermore, the efficient rotation speeds of the compressor and turbine are different regardless of whether the battery is generating electricity or charging. Therefore, connecting the compressor and turbine on the same shaft to drive them reduces the efficiency of the entire plant.

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide a pump-type heat storage battery that can be operated with even higher efficiency. [Means for solving the problem]

[0006] In order to solve the above problems, the pump type heat storage battery according to the present disclosure includes a compressor that compresses a working fluid, a turbine that is provided independently of the compressor and driven by the compressed working fluid, a first flow path through which the working fluid flows by connecting a discharge side of the compressor and an inlet side of the turbine, a heat storage tank provided on the first flow path, a second flow path through which the working fluid flows by connecting an exhaust side of the turbine and an inlet side of the compressor, a cold storage tank provided on the second flow path, an electric motor connected coaxially with the compressor, a generator connected coaxially with the turbine, and a power generator connected to the operating shaft. The compressor is provided with a switching unit that controls the flow direction of the fluid, and a rotation speed adjustment unit that independently adjusts the rotation speed of the compressor and the turbine, and the switching unit switches between a charging state in which the working fluid discharged from the compressor driven by the electric motor flows through the heat storage tank to the inlet side of the turbine, drives the turbine, and then flows through the cold storage tank to the inlet side of the compressor, and a power generation state in which the working fluid discharged from the compressor passes through the heat storage tank and becomes high temperature and high pressure, driving the turbine and the generator, and then flows through the cold storage tank to the inlet side of the compressor. Effect of the Invention

[0007] According to the present disclosure, it is possible to provide a pump type heat storage battery that can be operated with even higher efficiency. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a pump-type heat storage battery according to an embodiment of the present disclosure. [Diagram 2] 4 is a graph illustrating the relationship between corrected flow rate, pressure ratio, and efficiency of a compressor according to an embodiment of the present disclosure. [Diagram 3]4 is a graph illustrating the relationship between corrected flow rate and expansion ratio and efficiency of an embodiment of a turbine according to the present disclosure. [Figure 4] 1 is a table illustrating the relationship between speed, inlet temperature, and corrected speed in a state of charge and a state of generating for a compressor and a turbine according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a pump type heat storage battery 1 according to an embodiment of the present disclosure will be described with reference to FIGS.

[0010] (Configuration of pump-type heat storage battery) The pump-type heat storage battery 1 is a device that generates power using surplus electricity generated by, for example, a wind power generation facility or a solar power generation facility. As shown in Fig. 1, the pump-type heat storage battery 1 includes a compressor 10, a turbine 11, a first flow path 12, a heat storage tank 13, a second flow path 14, a cold storage tank 15, an electric motor 16, a generator 17, an inverter 18, a switching unit 19, and a rotation speed adjustment unit 20.

[0011] (Compressor) The compressor 10 takes in external air and compresses it to generate high-pressure air. Specifically, an axial flow type or centrifugal type is used as the compressor 10. Only one compressor 10 is provided in the system.

[0012] (Turbine) The turbine 11 is rotationally driven by air supplied from the outside. The rotational energy of the turbine 11 is extracted from a shaft end and used to drive a generator 17, which will be described later. The turbine 11 is provided independently of the compressor 10, and the rotating shaft of the compressor 10 and the rotating shaft of the turbine 11 are not connected to each other. Therefore, as will be described in detail later, the compressor 10 and the turbine 11 can be operated at different rotation speeds. Furthermore, only one turbine 11 is provided in the system.

[0013] (First flow path / heat storage tank) The first flow path 12 is a flow path that connects the discharge side of the compressor 10 and the inlet side of the turbine 11. Air flows as a working fluid in the first flow path 12. A heat storage tank 13 is provided on the first flow path 12. The heat storage tank 13 is a container filled with a heat storage material such as a phase change material, bricks, gravel, etc. When the working fluid passes through the heat storage tank 13, the thermal energy of the working fluid is stored in the heat storage tank 13.

[0014] (Second flow path / cold storage tank) The second flow passage 14 is a flow passage that connects the exhaust side of the turbine 11 and the inlet side of the compressor 10. Air flows as a working fluid in the second flow passage 14. A cold storage tank 15 is provided on the second flow passage 14. The cold storage tank 15 is a container filled with the same substance or object as the heat storage tank 13. When the working fluid passes through the cold storage tank 15, the cold energy of the working fluid is stored in the cold storage tank 15. In other words, the cold energy of the working fluid cools the cold storage material, and a low temperature state is maintained.

[0015] (Electric motor) The electric motor 16 is connected coaxially with the compressor 10. The electric motor 16 is used to temporarily drive the compressor 10 when the system is started up. The electric motor 16 is connected to a power source 40 via a first switch 30. This power source 40 is, for example, a wind power generation facility or a solar power generation facility, and surplus power generated by these facilities during the daytime is suitably used to drive the electric motor 16. The first switch 30 is an electric circuit element provided to connect / disconnect the power source 40 and the electric motor 16. In addition, an inverter 18 for converting the frequency is provided between the electric motor 16 and the first switch 30.

[0016] (Generator) The generator 17 is connected coaxially with the turbine 11. The generator 17 generates electricity based on the output (rotational energy) of the turbine 11. The turbine 11 is connected to a power grid 60 via a second switch 50. A large number of devices of power consumers are connected to this power grid 60. The second switch 50 is an electric circuit element provided for connecting / disconnecting the power grid 60 and the generator 17. In addition, an inverter 18 for converting the frequency is provided between the electric motor 16 and the second switch 50.

[0017] (Switching section) The switching unit 19 is a valve for controlling the flow direction of the working fluid in the first flow path 12 and the second flow path 14. Specifically, the switching unit 19 has a pair of first valve devices 71 and a pair of second valve devices 72. The first valve device 71 is provided on the first flow path 12. The first valve device 71 is a three-way valve, and by moving a valve body (not shown), it is possible to change the flow direction of the working fluid with respect to the heat storage tank 13 as shown in FIG. 1. Specifically, in the charging state and the power generating state of the pump type heat storage battery 1, the working fluid flows in the opposite directions from the compressor 10 to the turbine 11 and into the heat storage tank 13.

[0018] Similarly, the second valve device 72 is a three-way valve, and by moving a valve body (not shown), the flow direction of the working fluid can be changed with respect to the cold storage tank 15 as shown in Fig. 1. Specifically, in the charging state and the power generating state of the pump type heat storage battery 1, the working fluid flows in the opposite directions into the cold storage tank 15 midway from the turbine 11 to the compressor 10.

[0019] (Rotation speed adjustment unit) The rotation speed adjustment unit 20 is a control device for independently adjusting the rotation speeds of the compressor 10 and the turbine 11. As will be described in detail later, the compressor 10 and the turbine 11 are each operated at a rotation speed (referred to as a corrected rotation speed) at which their respective energy efficiency is optimized. The rotation speed adjustment unit 20 obtains this corrected rotation speed for each of the compressor 10 and the turbine 11 and issues an operation command.

[0020] (Pump-type heat storage battery operation: charging status) The pump type heat storage battery 1 described above can be switched by a switching unit 19 between a charging state in which electrical energy for generating power is generated within the system, and a power generation state in which power is actually supplied to the outside.

[0021] In the charging state, as shown by the solid line in Fig. 1, the working fluid discharged from the compressor 10 driven by the electric motor 16 flows through the heat storage tank 13 to the inlet side of the turbine 11. This drives the turbine 11. The low-temperature working fluid discharged from the turbine 11 flows through the cold storage tank 15 to the inlet side of the compressor 10. As this cycle continues, thermal energy is stored in the heat storage tank 13, and cold energy, which is at a relatively low temperature, is stored in the cold storage tank 15.

[0022] Here, the rotation speed of the compressor 10 is higher in the power generation state than in the charging state. More specifically, the rotation speed adjustment unit 20 drives the compressor 10 at a compressor corrected rotation speed that realizes a compressor corrected flow rate at which the efficiency of the compressor 10 becomes a predetermined optimum value and is below the surge limit (see the black dots in FIG. 2). The corrected flow rate is a value obtained by converting the obtained rotation speed N to the rotation speed Nc in the standard state when the atmospheric temperature t during operation is different from the temperature t0 in the standard state. The corrected rotation speed is a rotation speed given by 100 / √T5 when the rotation speed of the compressor 10 in the charging state is 100 and the temperature of the working fluid at the inlet of the compressor 10 is T5, as shown in FIG. 4. In other words, the actual rotation speed of the compressor 10 is higher in the power generation state than in the charging state, but the corrected rotation speed is the same in the charging state and the power generation state.

[0023] Furthermore, the rotation speed of the turbine 11 is smaller in the power generating state than in the charging state. More specifically, the rotation speed adjustment unit 20 drives the turbine 11 at a turbine corrected rotation speed that realizes a turbine corrected flow rate at which the efficiency of the turbine 11 becomes a predetermined optimum value (see the black dots in FIG. 3). As shown in FIG. 4, the corrected rotation speed is a rotation speed given by 100 / √T3, where the rotation speed of the turbine 11 in the charging state is 100 and the temperature of the working fluid at the inlet of the turbine 11 is T3. In other words, the actual rotation speed of the turbine 11 is smaller in the power generating state than in the charging state, but the corrected rotation speed is the same in the charging state and the power generating state.

[0024] (About power generation status) On the other hand, in the power generation state, as shown by the dashed line in Fig. 1, the working fluid discharged from the compressor 10 drives the turbine 11 and the generator 17 in a high-temperature and high-pressure state after passing through the heat storage tank 13. This results in power generation and supply by the generator 17. The low-temperature working fluid discharged from the turbine 11 flows into the inlet side of the compressor 10 via the cold storage tank 15. As this cycle continues, the energy in the heat storage tank 13 adds further thermal energy to the high-pressure working fluid discharged from the compressor 10, and the cold energy in the cold storage tank 15 further cools the working fluid discharged from the turbine 11 and heading toward the inlet of the compressor 10.

[0025] (Action and effect) Here, in the conventional pump-type heat storage battery 1, two compressors 10 and two turbines 11 are required for power generation and charging, which leads to increased construction and maintenance costs. Furthermore, regardless of the power generation state and the charging state, the efficient rotation speeds of the compressor 10 and the turbine 11 are different. Therefore, driving the compressor 10 and the turbine 11 by connecting them on the same shaft causes a decrease in the efficiency of the entire plant. In order to solve these problems, the above-mentioned configurations are adopted in this embodiment.

[0026] According to the above configuration, the compressor 10 and the turbine 11 are provided independently of each other, so that each can be driven independently at an efficient rotation speed. This makes it possible to further improve the efficiency of the entire device. For example, in the power generation state, the working fluid discharged from the turbine 11 flows into the compressor 10 after adiabatic expansion and heat dissipation in the cold storage tank 15. Therefore, in the power generation state, the temperature of the working fluid at the inlet of the compressor 10 tends to be lower than in the charging state. Conversely, in the turbine 11, the working fluid that has been compressed in the compressor 10 and passed through the heat storage tank 13 flows in. Therefore, in the power generation state, the temperature of the working fluid at the inlet of the turbine 11 tends to be higher than in the charging state. Even if the optimal operating conditions are different between the power generation state and the charging state, according to the above configuration, the turbine 11 and the compressor 10 can be driven independently of each other at a rotation speed that matches the temperature of each working fluid. Therefore, it is possible to significantly improve the efficiency of the entire device.

[0027] Here, in the power generation state, the working fluid that has been compressed by the compressor 10 and passed through the heat storage tank 13 flows into the turbine 11. Therefore, in the power generation state, the temperature of the working fluid at the inlet of the turbine 11 tends to be higher than in the charging state. Therefore, if the turbine 11 is driven at the same rotation speed in the charging state and the power generation state, the efficiency of the turbine 11 decreases in the charging state. With the above configuration, the rotation speed of the turbine 11 in the power generation state is higher than the rotation speed in the charging state. This makes it possible to drive the turbine 11 efficiently even in the charging state.

[0028] According to the above-described configuration, the rotation speed adjustment unit 20 determines the corrected rotation speed of the turbine 11 based on the corrected flow rate of the turbine 11 that optimizes the efficiency of the turbine 11. This makes it possible to drive the turbine 11 with high efficiency.

[0029] Here, in the power generation state, the working fluid discharged from the turbine 11 flows into the compressor 10 after undergoing adiabatic expansion and heat dissipation in the cold storage tank 15. Therefore, in the power generation state, the temperature of the working fluid at the inlet of the compressor 10 tends to be lower than in the charging state. Therefore, if the compressor 10 is driven at the same rotation speed in the charging state and the power generation state, a surge due to a high pressure ratio may occur in the charging state. According to the above configuration, the rotation speed of the compressor 10 in the power generation state is smaller than the rotation speed in the charging state. This makes it possible to suppress the occurrence of a surge and drive the compressor 10 efficiently.

[0030] According to the above-described configuration, the rotation speed adjusting unit 20 determines the corrected rotation speed of the compressor 10 based on the corrected flow rate of the compressor 10 that is equal to or less than the surge limit of the compressor 10. This makes it possible to drive the compressor 10 more stably with high efficiency.

[0031] According to the above configuration, it is possible to switch between a power generation state and a charging state by using only one compressor 10 and one turbine 11. This allows the construction and maintenance costs of the device to be significantly reduced. Therefore, the cost required for power generation is ultimately reduced, which contributes to the benefit of electricity consumers.

[0032] According to the above-mentioned configuration, the motor 16 for driving the compressor 10 is powered by surplus electricity from other power generating equipment. This allows the unused surplus electricity to be efficiently utilized, thereby achieving high levels of efficiency improvement in the entire power generation cycle and reduction in the loop load.

[0033] (Other embodiments) Although the embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like that do not depart from the gist of the present disclosure are also included.

[0034] For example, in the above embodiment, a configuration in which only one compressor 10 and one turbine 11 are provided has been described. However, it is also possible to configure a plurality of pump type heat storage batteries 1 so that they are connected in parallel with each other. That is, in this case, a configuration is adopted in which a plurality of compressors 10 and a plurality of turbines 11 are provided. With this configuration, it is possible to obtain the same effects as those described above.

[0035] Furthermore, the substances or objects filled in the heat storage tank 13 or the cold storage tank 15 are not limited to those mentioned above, and any substances having heat storage or cold storage properties can be suitably used.

[0036] In addition to the surplus power of the other power generating facilities described above, power from a battery or the like can be used as the power source for driving the electric motor 16. In this case, although the energy efficiency decreases, the power generation capacity can be maintained at the same level as that described above.

[0037] <Additional Notes> The pump type heat storage battery 1 described in each embodiment can be understood, for example, as follows.

[0038] (1) A pump-type heat storage battery 1 according to a first embodiment includes a compressor 10 that compresses a working fluid, a turbine 11 that is provided independently of the compressor 10 and that is driven by the compressed working fluid, a first flow path 12 through which the working fluid flows by connecting a discharge side of the compressor 10 and an inlet side of the turbine 11, a heat storage tank 13 provided on the first flow path 12, a second flow path 14 through which the working fluid flows by connecting an exhaust side of the turbine 11 and an inlet side of the compressor 10, a cold storage tank 15 provided on the second flow path 14, an electric motor 16 that is coaxially connected with the compressor 10, a generator 17 that is coaxially connected with the turbine 11, and a flow path for the working fluid. and a rotation speed adjustment unit 20 that independently adjusts the rotation speeds of the compressor 10 and the turbine 11. The switching unit 19 switches between a charging state in which the working fluid discharged from the compressor 10 driven by the electric motor 16 flows through the heat storage tank 13 to the inlet side of the turbine 11, drives the turbine 11, and then flows through the cold storage tank 15 to the inlet side of the compressor 10, and a power generation state in which the working fluid discharged from the compressor 10 drives the turbine 11 and the generator 17 in a high-temperature and high-pressure state after passing through the heat storage tank 13, and then flows through the cold storage tank 15 to the inlet side of the compressor 10.

[0039] According to the above configuration, the compressor 10 and the turbine 11 are provided independently of each other, so that they can be driven independently at efficient rotation speeds, thereby making it possible to further improve the efficiency of the entire device.

[0040] (2) A pump type heat storage battery 1 according to a second aspect is the pump type heat storage battery 1 according to (1), in which the rotation speed of the turbine 11 is greater in the power generating state than in the charging state.

[0041] Here, the temperature of the working fluid at the inlet of the turbine 11 tends to be higher in the power generating state than in the charging state. With the above configuration, the rotation speed of the turbine 11 in the power generating state is higher than the rotation speed in the charging state. This makes it possible to drive the turbine 11 efficiently even in the charging state.

[0042] (3) A pump-type heat storage battery 1 according to a third aspect is a pump-type heat storage battery 1 according to (1) or (2), wherein the rotation speed adjustment unit 20 drives the turbine 11 at a turbine 11 corrected rotation speed that achieves a turbine 11 corrected flow rate at which the efficiency of the turbine 11 becomes a predetermined optimum value.

[0043] According to the above-described configuration, the rotation speed adjustment unit 20 determines the corrected rotation speed of the turbine 11 based on the corrected flow rate of the turbine 11 that optimizes the efficiency of the turbine 11. This makes it possible to drive the turbine 11 with high efficiency.

[0044] (4) A pump type heat storage battery 1 according to a fourth aspect is the pump type heat storage battery 1 according to any one of the aspects (1) to (3), in which the rotation speed of the compressor 10 is smaller in the power generating state than in the charging state.

[0045] Here, the temperature of the working fluid at the inlet of the compressor 10 tends to be lower in the power generating state than in the charging state. With the above configuration, the rotation speed of the compressor 10 in the power generating state is smaller than the rotation speed in the charging state. This makes it possible to suppress the occurrence of surges and drive the compressor 10 efficiently.

[0046] (5) A pump type heat storage battery 1 according to a fifth aspect is a pump type heat storage battery 1 according to any one of the aspects (1) to (4), wherein the rotation speed adjustment unit 20 realizes a compressor 10 corrected flow rate at which the efficiency of the compressor 10 becomes a predetermined optimum value, and drives the compressor 10 at a compressor 10 corrected rotation speed at which the efficiency is below a surge limit.

[0047] According to the above-described configuration, the rotation speed adjusting unit 20 determines the corrected rotation speed of the compressor 10 based on the corrected flow rate of the compressor 10 that is equal to or less than the surge limit of the compressor 10. This makes it possible to drive the compressor 10 more stably with high efficiency.

[0048] (6) A pump type heat storage battery 1 according to a sixth aspect is a pump type heat storage battery 1 according to any one of the aspects (1) to (5), in which only one compressor 10 and one turbine 11 are provided.

[0049] According to the above configuration, it is possible to switch between a power generation state and a charging state and operate the system by using only one compressor 10 and one turbine 11. This makes it possible to significantly reduce the construction costs and maintenance costs of the system.

[0050] (7) A pump type heat storage battery 1 according to a seventh aspect is a pump type heat storage battery 1 according to any one of aspects (1) to (6), in which the power to drive the electric motor 16 is provided by surplus power from another power generation facility.

[0051] According to the above-mentioned configuration, the motor 16 for driving the compressor 10 is powered by surplus electricity from other power generating equipment. This allows the unused surplus electricity to be efficiently utilized, thereby achieving high levels of efficiency improvement in the entire power generation cycle and reduction in the loop load. [Explanation of symbols]

[0052] 1...Pump-type heat storage battery 10...Compressor 11...Turbine 12...First flow path 13...Heat storage tank 14...Second flow path 15...Cold storage tank 16...Electric motor 17...Generator 18...Inverter 19...Switching unit 20...Rotation speed adjustment unit 30...First switch 40...Power source 50...Second switch 60...Power grid 71...First valve device 72...Second valve device

Claims

1. A compressor that compresses a working fluid; a turbine provided independently of the compressor and driven by the compressed working fluid; a first flow passage through which the working fluid flows by connecting a discharge side of the compressor and an inlet side of the turbine; A heat storage tank provided on the first flow path; a second flow passage connecting an exhaust side of the turbine and an inlet side of the compressor, through which the working fluid flows; a cold storage tank provided on the second flow path; an electric motor coaxially connected to the compressor; a generator coaxially connected to the turbine; A switching unit for controlling a flow direction of the working fluid; a rotation speed adjusting unit that adjusts the rotation speeds of the compressor and the turbine independently; Equipped with The switching unit is a charging state in which the working fluid discharged from the compressor driven by the electric motor flows through the heat storage tank to the inlet side of the turbine, drives the turbine, and then flows through the cold storage tank to the inlet side of the compressor; A pump-type heat storage battery in which the working fluid discharged from the compressor passes through the heat storage tank and becomes high-temperature and high-pressure, driving the turbine and the generator, and switching between a power generation state in which the working fluid flows into the inlet side of the compressor through the cold storage tank.

2. The pump-type heat storage battery according to claim 1 , wherein the rotational speed of the turbine is greater in the generating state than in the charging state.

3. 3. The pump-type heat storage battery according to claim 1, wherein the rotation speed adjustment unit drives the turbine at a turbine corrected rotation speed that achieves a turbine corrected flow rate at which the efficiency of the turbine becomes a predetermined optimum value.

4. The pump type heat storage battery according to claim 1 or 2, wherein the rotation speed of the compressor is smaller in the generating state than in the charging state.

5. 3. The pump-type heat storage battery according to claim 1 or 2, wherein the rotation speed adjustment unit drives the compressor at a compressor corrected rotation speed that realizes a compressor corrected flow rate at which the efficiency of the compressor is a predetermined optimal value and is below a surge limit.

6. 3. The pump type heat storage battery according to claim 1, wherein only one each of the compressor and the turbine is provided.

7. 3. The pump-type heat storage battery according to claim 1, wherein the electric power for driving the electric motor is provided by surplus electric power from another power generation facility.

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