Compressed air energy storage device and energy storage device

Abstract

To achieve power leveling by power supply and demand adjustment of a factory.SOLUTION: An electric motor driven by electric power from a power transmission and distribution system to which a renewable energy power generation device is connected, a compressor driven by the electric motor, an accumulator tank that stores compressed air compressed by the compressor as compressed air or liquid air, an expander driven by the compressed air stored in the accumulator tank, a generator driven by the expander, a pipe through which the compressed air passes, a solenoid valve provided in the pipe, a pressure sensor that detects a pressure of the pipe, and a control device that controls the solenoid valve. Wherein the pipe includes a pneumatic supply pipe connected to the pneumatic device, and the control device controls the solenoid valve to drive the expander with compressed air having a pressure exceeding a predetermined pressure, and controls the solenoid valve to supply compressed air having a pressure equal to or lower than the predetermined pressure from the pneumatic supply pipe to the pneumatic device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an energy storage device, in particular to a compressed air energy storage device and a liquid air energy storage device. [Background technology]

[0002] Power generation using renewable energy sources such as wind and solar power generation depends on weather conditions, and as such, the amount of power generated can fluctuate and become unstable.To counter such fluctuations, compressed air energy storage (CAES) systems and liquid air energy storage (LAES) systems are known as systems that level out power generation output.

[0003] Energy storage devices (CAES devices or LAES devices) that utilize this CAES system or LAES system store electrical energy in a pressure storage tank as compressed air or liquefied air, and when electricity is needed, the compressed air drives an expander to operate a generator, generating electrical energy and leveling out output.

[0004] In such CAES devices, for example, Patent Document 1 discloses a technology for controlling the output of power according to power demand by using a tank with a relatively large capacity for long-period fluctuating power generated by natural energy and a tank with a relatively small capacity for short-period fluctuating power, thereby leveling out both long-period and short-period fluctuating power.

[0005] Furthermore, Patent Document 2 discloses a technology that prevents a decrease in the operating efficiency of the entire system by controlling the expander bypass switching unit to allow air to flow into the expander bypass flow path and bypass the expander main body when the pressure in the accumulator tank detected by the pressure sensor is lower than a predetermined value. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6368577 [Patent Document 2] Japanese Patent Application Publication No. 2017-8867 Summary of the Invention [Problem to be solved by the invention]

[0007] In a CAES system, for example, when generating electricity using a solar power generation system, the system operates a compressor during the daytime when excess power is generated, storing energy by storing compressed air. However, during the daytime, production equipment in the factory is in operation frequently, and although the amount of power generated is high, the amount of power consumed is also high.

[0008] The technologies in Patent Documents 1 and 2 do not take into consideration efficient energy storage while meeting the daytime power demand of factories. Therefore, there is room for improvement in order to effectively shift power from time periods with high power generation to time periods with low power generation (power leveling).

[0009] An object of the present invention is to provide an energy storage device that can achieve power leveling by adjusting the power supply and demand in a factory. [Means for solving the problem]

[0010] In order to solve the above problems, one representative energy storage device of the present invention is a compressed air energy storage device or liquid air energy storage device connected to pneumatic equipment driven by air pressure, and includes: an electric motor driven by power from a power transmission and distribution system to which a renewable energy power generation device is connected; a compressor driven by the electric motor; a pressure accumulator tank that stores the compressed air compressed by the compressor as compressed air or liquid air; an expander driven by the compressed air stored in the pressure accumulator tank; a generator driven by the expander; piping through which the compressed air passes; a solenoid valve provided in the piping; a pressure sensor that detects the pressure in the piping; and a control device that controls the solenoid valve, wherein the piping includes an air pressure supply piping connected to the pneumatic equipment; and the control device controls the solenoid valve to drive the expander with compressed air exceeding a predetermined pressure, and controls the solenoid valve to supply compressed air below the predetermined pressure from the air pressure supply piping to the pneumatic equipment. [Effects of the Invention]

[0011] According to the present invention, it is possible to achieve power leveling by adjusting the power supply and demand in a factory.

[0012] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a CAES apparatus according to a first embodiment of the present invention. [Figure 2] 3 is a flowchart showing an example of control of the CAES apparatus according to the first embodiment of the present invention. [Figure 3] FIG. 2 is a diagram illustrating an example of the operation of the CAES apparatus according to the first embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating an example of the operation of the CAES apparatus according to the first embodiment of the present invention. [Figure 5] FIG. 4 is a schematic diagram showing an example of the configuration of a CAES apparatus according to a second embodiment of the present invention. [Figure 6]10 is a flowchart showing an example of control of a CAES apparatus according to a second embodiment of the present invention. [Figure 7] FIG. 4 is a diagram showing an example of the operation of the CAES apparatus according to the second embodiment of the present invention. [Figure 8] FIG. 4 is a diagram showing an example of the operation of the CAES apparatus according to the second embodiment of the present invention. [Figure 9] FIG. 10 is a schematic diagram showing an example of the configuration of a CAES apparatus according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing an example of the operation of the CAES apparatus according to the third embodiment of the present invention. [Figure 11] FIG. 10 is a diagram showing an example of the operation of the CAES apparatus according to the third embodiment of the present invention. [Figure 12] FIG. 10 is a schematic diagram showing an example of the configuration of a CAES apparatus according to a fourth embodiment of the present invention. [Figure 13] FIG. 10 is a schematic diagram showing an example of the configuration of a CAES apparatus according to a fifth embodiment of the present invention. [Figure 14] 10 is a flowchart showing an example of control of a CAES apparatus according to a fifth embodiment of the present invention. [Figure 15] FIG. 10 is a diagram showing an example of the operation of the CAES apparatus according to the fifth embodiment of the present invention. [Figure 16] FIG. 10 is a diagram showing an example of the operation of the CAES apparatus according to the fifth embodiment of the present invention. [Figure 17] FIG. 10 is a schematic diagram showing an example of the configuration of a CAES apparatus according to a sixth embodiment of the present invention. [Figure 18] FIG. 10 is a schematic configuration diagram of a LAES apparatus according to a seventh embodiment of the present invention. [Figure 19] FIG. 13 is a schematic configuration diagram of a LAES apparatus according to an eighth embodiment of the present invention. [Figure 20] FIG. 13 is a schematic configuration diagram of a LAES apparatus according to a ninth embodiment of the present invention. [Figure 21] FIG. 16 is a schematic configuration diagram of a LAES apparatus according to a tenth embodiment of the present invention. [Figure 22] FIG. 22 is a schematic configuration diagram of a LAES apparatus according to an eleventh embodiment of the present invention. [Figure 23] FIG. 22 is a schematic configuration diagram of a LAES apparatus according to a twelfth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] (First embodiment) (1-1)CAES device FIG. 1 is a schematic diagram showing an example of the configuration of a CAES apparatus according to a first embodiment of the present invention.

[0016] The CAES device 1 is a device that levels the power (grid power) of a power transmission and distribution system 5 to which renewable energy power generation devices such as a solar power generation device 2 and a wind power generation device 3 are connected. The renewable energy power generation devices can supply power to a factory M, for example.

[0017] When the amount of power generated by the renewable energy power generation device is insufficient for the amount of power used by the factory M, the factory M makes up for the shortage with grid power. The renewable energy power generation device is also connected to the power transmission and distribution grid 5 via a power conditioner 4.

[0018] When the amount of power generated by the renewable energy power generation device is large compared to the amount of power used in the factory M, the CAES device 1 stores (charges) some of the grid power as compressed air energy. Also, when the amount of power generated by the renewable energy power generation device is small compared to the amount of power used in the factory M, the CAES device 1 generates power using the stored compressed air and returns (discharges) the power to the power transmission and distribution system 5. Also, the CAES device 1 can supply compressed air to pneumatic equipment M1 in the factory M that is driven by air pressure.

[0019] The CAES device 1 of this embodiment includes a compressor-expander unit 10, a heat storage unit 20, a pneumatic supply pipe 30, and a control device 70. The compressor-expander unit 10 includes a motor (electric motor) 11, a compressor 12, a pressure accumulator tank 13, an expander 14, and a generator 15. The heat storage unit 20 includes a high-temperature side heat storage tank 21 containing a heat storage medium such as water, a low-temperature side heat storage tank 22, and heat exchangers 24 and 25.

[0020] The control device 70 has functions such as controlling valves V31 - V33, VL1 - VL5 based on the pressure in the pneumatic supply pipe 30 detected by a pressure sensor.

[0021] The CAES device 1 compresses air to a pressure exceeding a predetermined pressure P2 (for example, about 0.6 MPa, P1 < P2) set higher than the pneumatic use pressure P1 (for example, about 0.5 MPa) for driving the pneumatic device M1 by the compressor 12. The compressed air exceeding the predetermined pressure P2 is supplied to the expander 14 for power generation, and the compressed air below the predetermined pressure P2 is supplied to the pneumatic device M1 via the pneumatic supply pipe 30.

[0022] A range may be provided for the predetermined pressure P2. However, the lower limit value of the predetermined pressure P2 is set higher than the pneumatic use pressure P1, and the upper limit value of the predetermined pressure P2 is set lower than the storage pressure P3. The storage pressure P3 is the upper limit value of the tank internal pressure of the pressure accumulator tank 13 in terms of specifications.

[0023] (1 - 1a) Compressor-Expander Unit The motor 11 is a prime mover for driving the compressor 12. A plurality of motors 11 are provided in the CAES device 1 of this embodiment, and two motors 11a and 11b are illustrated in FIG. 1. The motors 11a and 11b are connected to the power transmission and distribution system 5 via an inverter 16.

[0024] The compressor 12 is a rotary machine driven by the motor 11 to compress air. The CAES system 1 of this embodiment is provided with a plurality of compressors 12, and FIG. 1 illustrates two compressors: compressor 12a, which is a low-pressure compressor, and compressor 12b, which is a high-pressure compressor. The intake port of compressor 12a is open to the atmosphere, and the discharge port of compressor 12a is connected to the intake port of compressor 12b via pipe Lc1. The discharge port of compressor 12b is connected to heat exchanger 24 via pipe Lc2, and is further connected to accumulator tank 13 via heat exchanger 24 and piping system L.

[0025] The rotating shaft of compressor 12a is mechanically connected to the output shaft of motor 11a and performs a low-stage compression stroke in which it draws in and compresses the air. The rotating shaft of compressor 12b is mechanically connected to the output shaft of motor 11b and performs a high-stage compression stroke in which it further compresses the compressed air compressed by compressor 12a.

[0026] In the compressor-expander unit 10, multi-stage compression is performed by the compressors 12a and 12b, and the compressed air compressed by the compressors 12a and 12b is stored in the accumulator tank 13 via heat exchangers 24a and 24b. The CAES apparatus 1 of this embodiment is provided with a plurality of accumulator tanks 13, and three accumulator tanks 13a-13c are shown in FIG.

[0027] The piping system L described above includes a plurality of pipes L1-L6. Pipe L4 is connected to the compressed air outlet of heat exchanger 24, pipe L5 is connected to the compressed air inlet of heat exchanger 25, and pipe L6 connects pipes L4 and L5. Pipe L1 connects to accumulator tank 13a, pipe L2 connects to accumulator tank 13b, and pipe L3 connects to accumulator tank 13c, all to pipe L6. Through this piping system L, accumulator tanks 13a-13c are connected in parallel to heat exchangers 24 and 25.

[0028] The expander 14 is a rotary machine driven by compressed air stored in the accumulator tank 13. The CAES apparatus 1 of this embodiment is provided with a plurality of expanders 14, and Fig. 1 illustrates two expanders: expander 14a, which is a high-pressure expander driven by compressed air from the accumulator tank 13, and expander 14b, which is a low-pressure expander driven by compressed air discharged from the expander 14a.

[0029] The suction port of the expander 14a is connected to the accumulator tank 13 via a heat exchanger 25a and a pipe Le1, and the discharge port of the expander 14a is connected to the suction port of the expander 14b via a heat exchanger 25b and a pipe Le2. The discharge port of the expander 14b is open to the atmosphere. The expander 14a performs the high-stage expansion stroke, and the expander 14b performs the low-stage expansion stroke.

[0030] In the compressor-expander unit 10, multi-stage expansion is performed by the expanders 14a and 14b, and the air discharged from the expander 14b is released into the atmosphere.

[0031] The generator 15 generates electricity by being driven by the expander 14. The CAES apparatus 1 of this embodiment is provided with a plurality of generators 15, and FIG. 1 illustrates two generators: a generator 15a driven by the expander 14a and a generator 15b driven by the expander 14b.

[0032] The rotating shaft of generator 15a is mechanically coupled to the output shaft of expander 14a, and the rotating shaft of generator 15b is mechanically coupled to the output shaft of expander 14b. Furthermore, generators 15a and 15b are connected to the power transmission and distribution system 5 via power conditioner 17. Generators 15a and 15b are driven by expanders 14a and 14b to generate electricity (regenerate power) and return the regenerated power to the power transmission and distribution system 5.

[0033] (1-1b) Heat storage unit In the heat storage unit 20, heat from the compressed air compressed by the compressors 12a, 12b is recovered by the heat exchangers 24a, 24b to the heat storage medium from the low-temperature side heat storage tank 22. The high-temperature heat storage medium heated by the heat exchangers 24a, 24b is stored in the high-temperature side heat storage tank 21. The high-temperature heat storage medium stored in the high-temperature side heat storage tank 21 releases heat to the compressed air in the heat exchangers 25a, 25b, and the low-temperature heat storage medium cooled by the heat exchangers 25a, 25b returns to the low-temperature side heat storage tank 22. The heat storage unit 20 is provided with pumps 28, 29, and the heat storage medium is transported by the pumps 28, 29 to circulate through the heat storage unit 20.

[0034] (1-1c) Air pressure supply piping The air pressure supply pipe 30 is a pipe that supplies compressed air from the CAES apparatus 1 to pneumatically driven pneumatic equipment M1. The pneumatic equipment M1 is, for example, an air-driven device used in a factory M, and may be driven by compressed air generated by a compressor X (not shown) that serves as an air pressure source installed in the factory and supplied from air piping within the factory. In this embodiment, the air pressure supply pipe 30 is, for example, connected in parallel with the compressor X to air piping within the factory, and can supply compressed air to the pneumatic equipment M1 together with or instead of the compressor X.

[0035] In this embodiment, the air pressure supply pipe 30 includes pipes 31-34 that connect the accumulator tank 13 and pneumatic equipment M1 (air pipes in factory M). Pipe 31 connects to pipe L1 that connects to accumulator tank 13a, pipe 32 connects to pipe L2 that connects to accumulator tank 13b, and pipe 33 connects to pipe L3 that connects to accumulator tank 13c. Pipes 31-33 join together and are connected to pneumatic equipment M1 via pipe 34.

[0036] The pipe 31 is provided with a valve V31, the pipe 32 is provided with a valve V32, and the pipe 33 is provided with a valve V33. The pipe L4 and the pipe L5 are provided with a valve VL4 and a valve VL5, respectively.

[0037] Furthermore, a valve VL1 is provided in the above-mentioned pipe L1 (a portion farther from the pressure accumulator tank 13a than the branching portion of pipe 31). Similarly, a valve VL2 is provided in the pipe L2 (a portion farther from the pressure accumulator tank 13b than the branching portion of pipe 32), and a valve VL3 is provided in the pipe L3 (a portion farther from the pressure accumulator tank 13c than the branching portion of pipe 33).

[0038] These valves V31-V33 and VL1-VL5 are on-off valves that open and close the corresponding pipes, and can be controlled to open and close by the control device 70 by being electromagnetically driven, for example.

[0039] Furthermore, a pressure sensor P31 is provided in the pipe 31, a pressure sensor P32 in the pipe 32, a pressure sensor P33 in the pipe 33, and a pressure sensor P34 in the pipe 34. Furthermore, the above-mentioned pipe Lc1 is provided with a pressure sensor Pc, and the pipe Le2 is provided with a pressure sensor Pe.

[0040] These pressure sensors P31-P34, Pc, and Pe are pressure sensors that detect the pressure of the corresponding pipes. The pressures detected by these pressure sensors P31-P34, Pc, and Pe can be used to monitor the pressure in each part of the system of the CAES system 1. Furthermore, the control device 70 can automatically control the opening and closing of valves V31-V33 and VL1-VL5 based on the pressures detected by these pressure sensors P31-P34, Pc, and Pe.

[0041] (1-1d) Control device The control device 70 is connected to pressure sensors P31-P34, Pc, Pe, power conditioner 4, and a power meter 71 of factory M (which may be a computer in the control room of factory M, etc.), and inputs data such as the detected pressures of the pressure sensors P31-P34, Pc, Pe, the power generation amount from a power meter 72 that measures the power generation amount of the renewable energy power generation device, and the power demand of factory M (power demand for the entire factory M, power demand for the pneumatic system).

[0042] The control device 70 is a computer that executes a control program and the like for the CAES apparatus 1. The control device 70 can output open / close commands to the valves V30-V34, VL1-VL5, start commands / stop commands / rotation speed commands to the motors 11a, 11b and the pumps 28, 29, rotation speed commands to the generators 15a, 15b, power generation output commands, and the like.

[0043] (1-2) Basic operation The basic operations of the CAES apparatus 1, specifically the charging operation, discharging operation, and air pressure supply operation, will be explained in order.

[0044] (1-2a) Charging operation During the charging operation to generate and store compressed air, the CAES apparatus 1 operates as follows: During the charging operation, the valves V31-V33 of the air pressure supply pipe 30 and the valve VL5 of the pipe L5 of the heat exchanger 25 are typically closed. Also, the valve VL4 of the pipe L4 of the heat exchanger 24 is open.

[0045] First, motors 11a and 11b are driven by input power from the power transmission and distribution system 5. Motors 11a and 11b drive compressors 12a and 12b, and two-stage compression is performed by compressors 12a and 12b. Compressor 12a draws in atmospheric air from its intake port and performs a first-stage adiabatic compression. Compressor 12b draws in compressed air discharged from its discharge port and performs a second-stage adiabatic compression, discharging high-pressure, high-temperature compressed air. This high-temperature, high-pressure compressed air flows into heat exchangers 24a and 24b and exchanges heat with a low-temperature heat storage medium supplied from low-temperature-side heat storage tank 22 to heat exchangers 24a and 24b by pump 29. This heat exchange raises the temperature of the low-temperature heat storage medium and causes it to be stored in high-temperature-side heat storage tank 21. Meanwhile, the compressed air cools down and flows into and is stored in pressure storage tank 13.

[0046] At that time, the compressed air is stored in the accumulator tanks 13a, 13b, and 13c in this order, for example. That is, when the accumulator tanks 13a, 13b, and 13c are all below a predetermined storage pressure P3 (for example, about 1.2 MPa, P1 < P2 < P3), the valves VL2 and VL3 of the accumulator tanks 13b and 13c are closed, the valve VL1 of the accumulator tank 13a is opened, and compressed air is fed into the accumulator tank 13a.

[0047] After that, when the pressure of the accumulator tank 13a detected by the pressure sensor P31 reaches the storage pressure P3, the valves VL1 and VL3 of the accumulator tanks 13a and 13c are closed, the valve VL2 of the accumulator tank 13b is opened, and the storage destination of the compressed air is switched to the accumulator tank 13b.

[0048] When the pressure of the accumulator tank 13b detected by the pressure sensor P32 reaches the storage pressure P3, the valves VL1 and VL2 of the accumulator tanks 13a and 13b are closed, the valve VL3 of the accumulator tank 13c is opened, and the storage destination of the compressed air is switched to the accumulator tank 13c.

[0049] When the pressure of the accumulator tank 13c detected by the pressure sensor P33 reaches the storage pressure P3, the valve VL3 is closed, and the storage of compressed air in the accumulator tank 13c is stopped.

[0050] Through the above operations, a part of the grid power is converted into the energy of compressed air and the heat storage medium and stored (charged) in the CAES device 1.

[0051] [[ID=,19]] (1-2b) Discharge operation During the discharge operation of driving the generator with compressed air to generate electricity, the CAES device 1 operates as follows. During the discharge operation, typically, the valves V31-V33 of the pneumatic supply pipe 30 and the valve VL4 of the pipe L4 of the heat exchanger 24b are closed. Also, the valve VL5 of the pipe L5 of the heat exchanger 25a is opened.

[0052] First, the compressed air stored in the accumulator tank 13 is supplied to the heat exchanger 25a. At this time, the compressed air in the accumulator tank with the higher pressure is given priority. When all the accumulator tanks have the stored pressure P3, the compressed air is supplied in a predetermined order (for example, the order of the accumulator tanks 13a, 13b, and 13c).

[0053] For example, when the pressure accumulator tanks 13a, 13b, and 13c are all at storage pressure P3, the valves VL2 and VL3 of the pressure accumulator tanks 13b and 13c are closed, and the valve VL1 of the pressure accumulator tank 13a is opened, sending the compressed air from the pressure accumulator tank 13a to the heat exchanger 25a.

[0054] Thereafter, when the pressure in the accumulator tank 13a detected by the pressure sensor P31 drops to a predetermined pressure P2, the valves VL1 and VL3 of the accumulator tanks 13a and 13c are closed, the valve VL2 of the accumulator tank 13b is opened, and the source of compressed air to the heat exchanger 25 is switched to the accumulator tank 13b.

[0055] When the pressure in the accumulator tank 13b detected by the pressure sensor P32 drops to a predetermined pressure P2, the valves VL1 and VL2 of the accumulator tanks 13a and 13b are closed, the valve VL3 of the accumulator tank 13c is opened, and the source of compressed air to the heat exchanger 25 is switched to the accumulator tank 13c.

[0056] When the pressure in the accumulator tank 13c detected by the pressure sensor P33 drops to a predetermined pressure P2, the valve VL3 is closed and the supply of compressed air from the accumulator tank 13c to the heat exchanger 25 is stopped.

[0057] The compressed air supplied from the pressure storage tank 13 flows into the heat exchanger 25a and exchanges heat with the high-temperature heat storage medium supplied from the high-temperature side heat storage tank 21 to the heat exchangers 25a and 25b by the pump 28. The high-temperature heat storage medium becomes cold through this heat exchange and is stored in the low-temperature side heat storage tank 22.

[0058] Meanwhile, the compressed air increases in temperature and is drawn into expanders 14a and 14b where it undergoes adiabatic expansion, driving generators 15a and 15b. The compressed air that has undergone the first stage adiabatic expansion in expander 14a is drawn into expander 14b where it undergoes the second stage adiabatic expansion, driving expander 14b. The low-temperature, low-pressure air that has undergone the adiabatic expansion in expander 14b is released into the atmosphere from the discharge port of expander 14b.

[0059] When the expanders 14a and 14b are driven by the two-stage expansion of the compressed air, the expanders 14a and 14b drive the generators 15a and 15b, respectively, and the power generation outputs of the generators 15a and 15b are supplied to the power transmission and distribution system 5 via the power conditioner 17.

[0060] Through the above operations, the compressed air energy stored in the CAES device 1 is regenerated and returned (discharged) to grid power.

[0061] (1-2c) Air pressure supply operation During the air pressure supply operation for supplying compressed air at approximately a predetermined pressure P2 to the air pressure device M1, the CAES apparatus 1 operates as follows.

[0062] During air pressure supply operation, compressed air is supplied to the pneumatic device M1 in order from the accumulator tanks 13a-13c whose pressure has dropped to a predetermined pressure P2 (principally, equal to or greater than the air working pressure P1). Alternatively, if there are multiple accumulator tanks with a pressure of about the predetermined pressure P2, compressed air is supplied to the pneumatic device M1 in order from the accumulator tank with the lowest pressure.

[0063] For example, when the pressure in the accumulator tanks 13a and 13b is high and close to the storage pressure P3, and the pressure in the accumulator tank 13c is close to the predetermined pressure P2, first, the valve V33 on the pipe 33 of the air pressure supply pipe 30 corresponding to the accumulator tank 13c is opened, and the valve VL3 on the pipe L3 of the accumulator tank 13c is closed, and the compressed air stored in the accumulator tank 13c is supplied to the pneumatic equipment M1.

[0064] At this time, the valves V31 and V32 corresponding to the accumulator tanks 13a and 13b of the air pressure supply pipe 30 are closed. In this way, by switching the valves V31-V33 and VL1-VL3 between open and closed, compressed air at approximately a predetermined pressure P2 is supplied from the accumulator tanks 13a-13c to the pneumatic device M1 as appropriate.

[0065] In addition, when multiple accumulator tanks are provided as in the CAES apparatus 1 of this embodiment, compressed air is typically supplied to the pneumatic device M1 from any one of the accumulator tanks. For example, when compressed air is supplied to the pneumatic device M1 from the accumulator tank 13c and the pressure in the accumulator tank 13c falls below the air operating pressure P1, if the pressure in either the accumulator tank 13a or 13b is approximately a predetermined pressure P2, the supply source of compressed air to the pneumatic device M1 is switched to the accumulator tank 13a or 13b by operating a valve.

[0066] (1-3) Operation mode Table 1 shows the operation of each device in the CAES apparatus 1 in each operation mode in this embodiment.

[0067] [Table 1] The operation mode of the CAES apparatus 1 will be described.

[0068] (1-3a) Charging-only operation mode In the charging-only operation mode, the CAES apparatus 1 performs only the charging operation described above, which generates and stores compressed air.

[0069] (1-3b) Discharge-only operation mode In the operation mode in which only discharge is performed, the CAES apparatus 1 performs only the above-mentioned discharge operation of driving the generator with compressed air to generate electricity.

[0070] (1-3c) Operation mode with only air pressure supply In the operation mode in which only air pressure supply is performed, the CAES apparatus 1 performs only the air pressure supply operation described above.

[0071] (1 - 3d) Operating mode for simultaneous charging and pneumatic supply In the operating mode for simultaneous charging and pneumatic supply, the CAES device 1 performs the above charging operation and pneumatic supply operation simultaneously. At this time, different accumulator tanks are used for the charging operation and the pneumatic supply operation.

[0072] For example, similar to the above charging operation, the valve VL5 of the pipe L5 of the heat exchanger 25a is closed, and the valve VL4 of the pipe L4 of the heat exchanger 24 is opened. However, at this time, among the valves V31 - V33 of the pneumatic supply pipe 30, the valve of the pneumatic supply pipe connected to the tank with the lowest storage pressure (for example, V33) is opened, and the rest are closed.

[0073] The compressors 12a and 12b are driven by the motors 11a and 11b, and two - stage compression is performed by the compressors 12a and 12b.

[0074] The compressed air is stored in the tank where the accumulator tank has a pressure lower than the predetermined storage pressure P3 (for example, about 1.2 MPa, P1 < P2 < P3). For example, the valves VL2 and VL3 of the accumulator tanks 13b and 13c are closed, the valve VL1 of the accumulator tank 13a is opened, and the compressed air is sent into the accumulator tank 13a.

[0075] After that, when the pressure of the accumulator tank 13a detected by the pressure sensor P31 reaches the storage pressure P3, the valves VL1 and VL3 of the accumulator tanks 13a and 13c are closed, the valve VL2 of the accumulator tank 13b is opened, and the storage destination of the compressed air is switched to the accumulator tank 13b.

[0076] At the same time, the valve V33 of the pipe 33 of the pneumatic supply pipe 30 corresponding to the accumulator tank 13c is opened, and the compressed air stored in the accumulator tank 13c is supplied to the pneumatic device M1. At that time, the valves V31 and V32 of the pneumatic supply pipe 30 corresponding to the accumulator tanks 13a and 13b are closed. In this way, by switching the opening and closing of the valves V31 - V33 and VL1 - VL3, compressed air with a pressure of about the predetermined pressure P2 is appropriately supplied from the accumulator tanks 13a - 13c to the pneumatic device M1.

[0077] By the above operation, discharge and air pressure supply operations are performed simultaneously.

[0078] (1-3e) Operation mode in which discharge and air pressure supply are performed simultaneously In the operation mode in which discharge and air pressure supply are performed simultaneously, the CAES apparatus 1 simultaneously performs the above-mentioned discharge operation and air pressure supply operation, and in this case, different accumulator tanks are used for the discharge operation and the air pressure supply operation.

[0079] For example, when the accumulator tank 13a is at a high pressure close to the storage pressure P3 and the accumulator tanks 13b and 13c are at a predetermined pressure P2, the valve VL4 of the pipe L4 of the heat exchanger 24b is closed. Also, the valve VL5 of the pipe L5 of the heat exchanger 25a is open, the valve VL1 of the pipe L1 connected to the accumulator tank 13a is open, and the other valves VL2 and VL3 are closed. However, at this time, among the valves V31-V33 of the air pressure supply pipe 30, the valve (for example, V33) of the air pressure supply pipe connected to the tank with the lowest storage pressure is opened, and the rest are closed.

[0080] First, compressed air from the pressure storage tank 13a is sent to the heat exchanger 25a, where it exchanges heat with a high-temperature heat storage medium supplied from the high-temperature side heat storage tank 21 to the heat exchangers 25a and 25b by the pump 28, raising the temperature of the compressed air. The compressed air is then drawn into the expanders 14a and 14b, where it undergoes adiabatic expansion and drives the generators 15a and 15b. The power output of the generators 15a and 15b is supplied to the power transmission and distribution system 5 via the power conditioner 17.

[0081] When the pressure in the accumulator tank 13a detected by the pressure sensor P31 drops to a predetermined pressure P2, the valves VL1 and VL3 of the accumulator tanks 13a and 13c are closed, the valve VL2 of the accumulator tank 13b is opened, and the source of compressed air to the heat exchanger 25 is switched to the accumulator tank 13b.

[0082] At the same time, valve V33 of pipe 33 of air pressure supply pipe 30 corresponding to accumulator tank 13c is opened to supply compressed air stored in accumulator tank 13c to pneumatic device M1. At this time, valves V31 and V32 corresponding to accumulator tanks 13a and 13b of air pressure supply pipe 30 are closed. In this way, by switching the opening and closing of valves V31-V33 and VL1-VL3, compressed air at approximately a predetermined pressure P2 is supplied appropriately from accumulator tanks 13a-13c to pneumatic device M1.

[0083] For the air pressure supply, an accumulator tank 13c is used, which has an internal tank pressure that has dropped to a predetermined pressure P2 and is separate from the accumulator tanks 13a and 13b used in the discharging operation. The pressure in the accumulator tank 13c gradually drops due to the air pressure supply. When the pressure in the accumulator tank 13c drops to the air pressure usage pressure P1, the air pressure supply from the accumulator tank 13c can no longer be continued. Therefore, if the internal tank pressure of the other accumulator tanks 13a and 13b is higher than the predetermined pressure P2, the air pressure supply source is switched to the other accumulator tank (for example, accumulator tank 13b), and compressed air is supplied from accumulator tank 13b to the pneumatic device M1.

[0084] Furthermore, if there is no other accumulator tank other than the accumulator tank being used for the discharging operation whose internal tank pressure is equal to or greater than the predetermined pressure P2, the valve VL5 of the pipe L5 is closed, the discharging operation is terminated, the valve (V32 in this case) of the air pressure supply pipe 30 is opened, and the compressed air in the accumulator tank 13b is switched from the discharging operation to air pressure supply to the pneumatic device M1.

[0085] (1-4) Adjustment of power supply and demand The following describes the switching of operation modes and the adjustment of power supply and demand in the CAES system 1. When switching modes, the operation / stop of each device and the opening / closing operation of the valves are performed by commands from the control device 70.

[0086] The control device 70 inputs the power generation amount of the renewable energy power generation device input from the power meter 72, the power consumption amount of the factory M input from the power meter 71, and the pressure of the air pressure supply pipe 30 detected by the pressure sensors P31-P34, and if the power generation amount (W72) of the renewable energy power generation device is less than the power consumption amount (W71) of the factory M and the pressure (P34) of the air pressure supply pipe 30 is equal to or greater than the air pressure usage pressure P1 and equal to or less than a predetermined pressure P2, it opens the valves V31-V33 as appropriate and supplies compressed air from the air pressure supply pipe 30 to the air pressure equipment M1.

[0087] For example, when only the accumulator tank 13c (pipe 33) among the accumulator tanks 13a-13c (pipes 31-33) is at an air pressure working pressure P1 or higher and a predetermined pressure P2 or lower, the valve V33 is opened and air pressure is supplied using the accumulator tank 13c.

[0088] (1-4a) When power generation exceeds power demand When the power generation amount (W72) of renewable energy power generation devices such as solar power generation devices 2 and wind power generation devices 3 connected to the power transmission and distribution system 5 exceeds the power consumption amount (W71) of the factory M, and surplus power is generated, the CAES device 1 is operated in a charging operation mode, and the surplus power is stored as compressed air.

[0089] At this time, if the operation demand for the pneumatic equipment M1 is high and the amount of air pressure used is large, the CAES equipment 1 operates in an operation mode in which charging and air pressure supply are performed simultaneously. The operation demand for the pneumatic equipment M1 is determined by an operator or the control device 70 based on monitoring data received from the factory M, and the operation mode is switched manually or automatically. By supplying the compressed air used by the pneumatic equipment M1 from the accumulator tank 13, the power demand for producing compressed air in the factory M is reduced, and the charging amount in the CAES equipment 1 increases by 10-20% of the power used by the factory M.

[0090] For example, when there is no demand for operation of the pneumatic equipment M1, such as when the production equipment of the factory M is out of service, the CAES device 1 operates in an operation mode in which only charging is performed. Because the compressed air stored in the CAES device 1 can be used not only for discharge but also as air pressure in the pneumatic equipment M1, it is desirable to store a sufficient amount of compressed air during periods of low power demand.

[0091] For example, if the solar power generation device 2 generates a large amount of power and surplus power is generated during the day, the CAES device 1 can be operated in discharge mode at night to equalize power usage between day and night, and power costs can be reduced by reducing power usage in the transmission and distribution system 5 during the day.

[0092] (1-4b) When power generation is below power demand When the power generation amount (W72) of renewable energy power generation devices such as solar power generation devices 2 and wind power generation devices 3 connected to the power transmission and distribution system 5 is less than the power consumption amount (W71) of the factory M, operation in three operating modes is possible.

[0093] When there is a request to operate the pneumatic equipment M1, the CAES equipment 1 operates in an operation mode that only supplies air pressure, and supplies compressed air to the pneumatic equipment M1. Because there is no longer any demand for electricity to produce compressed air in the factory M, the amount of electricity generated by the renewable energy power generation equipment and the amount of electricity used by the factory M are balanced at a value that is about 10-20% lower than when compressed air is produced in the factory M, and the scale of power generation by the renewable energy power generation equipment can be reduced.

[0094] While performing air pressure supply operation, it is also possible to switch to an operation mode that performs both discharge and air pressure supply when the amount of power used in the factory M needs to be covered. In this embodiment, when there is a request to operate the pneumatic device M1, air pressure supply is given priority over discharge, thereby enabling highly efficient supply and demand adjustment with less energy loss.

[0095] Furthermore, when there is no request to operate the pneumatic device M1, the CAES device 1 operates in an operation mode in which only discharge is performed. The CAES device 1 operates in the operation mode in which discharge is performed, and generates electricity from the compressed air and supplies it to the power transmission and distribution system 5.

[0096] (1-4c) Determining the operating mode To perform the above-described operation, the control device 70 must determine the operation mode to be selected and automatically control the electrically powered devices including the valves V31-V33 and VL1-VL5. The operation mode is determined according to the flow shown in FIG.

[0097] FIG. 2 is a flowchart showing an example of control of the CAES apparatus according to the first embodiment of the present invention.

[0098] First, the control device 70 determines whether the current time is in the late night hours, for example, from 2:00 to 5:00 (step S101), and if the current time is in the late night hours, the control device 70 selects operation in the charging mode (step S105).

[0099] On the other hand, if the current time is not in the late night hours, the control device 70 determines whether the power consumption (W71) of the factory M exceeds (or is balanced with) the power generation amount (W72) of the renewable energy power generation device (step S102). This can be determined by the control device 70 from the power consumption of the factory M input from the wattmeter 71 and the power generation amount of the renewable energy power generation device input from the power conditioner 4.

[0100] If the power consumption (W71) of the factory M exceeds the power generation amount (W72) of the renewable energy power generation device, and if the power consumption (W71) of the factory M is balanced with the power generation amount (W72) of the renewable energy power generation device (YES in step S102), the control device 70 determines whether there is a request to operate the pneumatic equipment M1 (step S103).

[0101] If there is no request to operate the pneumatic device M1 (NO in step S103), the control device 70 selects operation in the discharge mode (step S107) and increases the power supply. At this time, the control device 70 opens the valve VL5, starts operation of the expander 14, and issues a power generation command to the power conditioner 17 to operate in an operation mode in which only discharge is performed.

[0102] On the other hand, if there is an air pressure request from the pneumatic equipment M1 (YES in step S103), the control device 70 selects operation in the air pressure supply mode (step S106) and reduces the amount of power used by the factory M. At this time, the control device 70 checks and compares the pressures (P31 to P33) of the accumulator tanks 13, opens the valve connecting the tank with the lowest pressure that is equal to or higher than the predetermined pressure P2 to the air pressure supply piping 30, and supplies air pressure to the pneumatic equipment M1. The control device 70 also issues a stop command to the inverter 16, stops the operation of the compressors 12a and 12b, and operates in an operation mode in which only air pressure is supplied.

[0103] In this way, when there is a request to operate the pneumatic device M1, the control device 70 does not perform a discharge operation, and prioritizes operation in an operation mode in which only air pressure is supplied.

[0104] On the other hand, if the power consumption (W71) of the factory M is lower than the power generation amount (W72) of the renewable energy power generation device (NO in step S102), the control device 70 determines whether there is a request to operate the pneumatic equipment M1 (step S104).

[0105] If there is no request to operate the pneumatic device M1 (NO in step S104), the control device 70 selects operation in a charging mode in which only charging operation is performed (step S109). At this time, the control device 70 opens the valve VL4, checks and compares the pressures (P31 to P33) of the accumulator tank 13, opens the valve connected to the tank with the highest pressure that is equal to or lower than the pneumatic operating pressure P1, and performs charging.

[0106] On the other hand, if there is a request to operate the pneumatic device M1 (YES in step S104), the control device 70 selects operation in a mode in which charging and air pressure supply are performed (step S108). At this time, the control device 70 checks and compares the pressures (P31 to P33) of the accumulator tanks 13, and opens the valve connecting the tank with the lowest pressure that is equal to or higher than the predetermined pressure P2 to the air pressure supply pipe 30 to supply air pressure to the pneumatic device M1.

[0107] 3 and 4 show the changes in the pressure in the accumulator tank 13, the outputs of the compressor 12 and the expander 14, and the amount of electric power when the system is operated in this manner.

[0108] 3 and 4 are diagrams showing an example of the operation of the CAES apparatus according to the first embodiment of the present invention, in which Fig. 3 shows changes during the main time period in the morning, and Fig. 4 shows changes during the main time period in the afternoon.

[0109] In the flow shown in Figure 2, the operating mode is switched by comparing the power generation amount (W72) of the renewable energy power generation device input from the power conditioner 4 with the power consumption amount (W71) of the factory M input from the power meter 71, but the switching may also be performed when the values ​​of W71 and W72 change beyond a predetermined threshold.

[0110] Alternatively, the switching may be performed when a predetermined time has elapsed since the values ​​of W71 and W72 have changed beyond a predetermined threshold.

[0111] Also, as shown in Figure 3, it is possible to prioritize pre-programmed operating modes depending on the time of day, such as prioritizing operation in charging mode during the late night hours from 2:00 to 5:00.

[0112] (1-5) Effects When introducing renewable energy power generation at facilities such as Factory M with the aim of achieving carbon neutrality, power leveling technology and energy supply and demand adjustment technology are required to make renewable energy the main power source.

[0113] For example, when using the solar power generation system 2, the CAES system 1 stores surplus energy by driving the compressor 12 and storing compressed air during the day when surplus power can be generated. However, during the day, the operating rate of production equipment in the factory M is high, and although the amount of power generated is large, the amount of power consumed by the factory M is also large. In order to increase the amount of energy stored during the day in order to effectively shift power to times when power generation is low (power leveling), it is rational not only to increase the amount of power generated by the renewable energy power generation system but also to curb the power consumption of the factory M, which is on the demand side.

[0114] In contrast, in this embodiment, by supplying compressed air from the CAES device 1 to the pneumatic equipment M1 used in the factory M as described above, the power demand of the factory M can be reduced by the amount of driving power of the compressor (not shown) for supplying air pressure in the factory M.

[0115] It is generally said that the power consumption of the pneumatic system for supplying compressed air used as a power source in a factory is about 10-20% of the factory's total power consumption. Therefore, by utilizing the compressed air stored in the CAES apparatus 1 for the pneumatic system of factory M, as in this embodiment, it is possible to reduce the power demand for air pressure supply in factory M while ensuring the necessary air pressure supply, and thus the power consumption of factory M can be significantly reduced.

[0116] Furthermore, unlike the discharge mode, which generates electricity using air that has been compressed to a high pressure, operation in air pressure supply mode eliminates energy loss during expansion to generate electricity and allows for highly efficient use of the compressed air energy. Therefore, when there is a request to operate the pneumatic device M1, prioritizing air pressure supply over discharge enables highly efficient supply and demand adjustment with less energy loss.

[0117] In this way, the CAES apparatus 1 can adjust the power demand of the factory M by supplying air pressure while charging and discharging, and can store surplus power, adjust power generation, and adjust supply and demand by demand response.

[0118] The CAES device 1 can rationally level out power by adjusting the power supply and demand of the factory M, for example by suppressing the power demand of the factory M during the day, and is expected to contribute to making renewable energy the main power source and reducing the amount of grid power used. This makes it possible to minimize the amount of grid power used that is derived from fossil fuels, and to reduce carbon dioxide emissions caused by the use of fossil fuels.

[0119] (Second embodiment) FIG. 5 is a schematic diagram showing an example of the configuration of a CAES apparatus according to the second embodiment of the present invention.

[0120] In FIG. 5, elements that are the same as or correspond to those in the embodiment already described are given the same reference numerals as in the previously described drawings, and descriptions thereof will be omitted as appropriate.

[0121] (2-1) CAES device The CAES apparatus 1 of this embodiment differs from the first embodiment in that the air pressure supply pipe 30 includes pipe 35, the air pressure supply pipe 30 includes pipe 36, and the CAES apparatus 1 is provided with pipe 37.

[0122] The pipe 35 connects the pipe Le2, which connects the high-pressure stage expander 14a and the low-pressure stage expander 14b, to the pneumatic equipment M1. The pipe 36 connects the pipe Lc1, which connects the low-pressure stage compressor 12a and the high-pressure stage compressor 12b, to the pneumatic equipment M1.

[0123] Furthermore, the pipe 37 connects the pipe Lc1, which connects the low-pressure stage compressor 12a and the high-pressure stage compressor 12b, to the pipes L1-L3. The pipe 37 connects the accumulator tanks 13a-13c in parallel to the compressor 12a.

[0124] The piping 37 is configured to include piping 37a-37c that connects piping Lc1, which connects the low-pressure stage compressor 12a and the high-pressure stage compressor 12b, to the accumulator tank 13. The piping 37a is connected to piping L1, which connects to the accumulator tank 13a, the piping 37b is connected to piping L2, which connects to the accumulator tank 13b, and the piping 37c is connected to piping L3, which connects to the accumulator tank 13c. The piping 37a-37c join together and are connected to the high-pressure stage compressor 12b via piping 37d.

[0125] The pipe 37a is provided with a valve Vc1, the pipe 37b with a valve Vc2, and the pipe 37c with a valve V37c.

[0126] In this embodiment, the pipe 35 connects the pipe Le2 to the pipe 34. The pipe 36 connects the pipe Lc1 to the pipe 34. The pipe 35 is provided with a valve V35, the pipe Le2 (the portion of the pipe 35 on the side of the low-pressure stage expander 14b relative to the branching point of the pipe 35) is provided with a valve Ve, the pipe 36 is provided with a valve V36, and the pipe Lc1 (the portion of the pipe 36 on the side of the high-pressure stage compressor 12b relative to the branching point of the pipe 36) is provided with a valve Vc.

[0127] Valves V35, Ve, V36, Vc, Vc1, Vc2, and Vc2 are on-off valves similar to valve V31, etc. Pressure sensor Pe is provided in pipe Le2 at a location on the side of the high-pressure stage expander 14a relative to the branch point of pipe 35. Pressure sensor Pc is provided in pipe Lc1 at a location on the side of the low-pressure stage compressor 12a relative to the branch point of pipe 36.

[0128] Other hardware configurations of the CAES apparatus 1 of the second embodiment are similar to those of the first embodiment.

[0129] (2-2) Basic operation The operation of the CAES apparatus 1 of the second embodiment will be described. In this embodiment, the charging operation and discharging operation are the same as in the first embodiment, so the air pressure supply operation will be described here.

[0130] In this embodiment, as in the first embodiment, air pressure can be supplied to the pneumatic device M1 sequentially from the pressure accumulator tanks whose pressure has dropped to the predetermined pressure P2, and if there are multiple pressure accumulator tanks with pressures around the predetermined pressure P2, compressed air can be supplied to the pneumatic device M1 preferentially from the pressure accumulator tank with the lowest pressure.

[0131] Additionally, in this embodiment, the air pressure supply pipe 30 includes the pipe 35, so that the discharge operation and the air pressure supply operation can be performed simultaneously using compressed air supplied from the same pressure accumulator tank.

[0132] For example, if all of the accumulator tanks 13a-13c are at a high pressure close to the storage pressure P3 and no accumulator tank has its pressure reduced to approximately the predetermined pressure P2, then valves V31-V33, Ve, and VL4 are closed, valves VL5 and V35 are open, and one of valves VL1-VL3 is opened. This allows high-pressure compressed air from one of the accumulator tanks 13a-13c to be supplied to the first-stage expander 14a, and power can be generated and discharged by the generator 15a.

[0133] The compressed air that drives the expander 14a is reduced in pressure to approximately a predetermined pressure P2 by adiabatic expansion, discharged from the expander 14a, and supplied to the pneumatic device M1 through the piping 35 via the valve V35. In this embodiment, of the expanders 14a and 14b, only the expander 14a performs a discharge operation by single-stage expansion, and the compressed air reduced in pressure by single-stage expansion is also supplied to the pneumatic device M1.

[0134] Furthermore, in this embodiment, since the air pressure supply pipe 30 includes the pipe 36, for example, by closing the valve Vc and opening the valve V36 and operating only the compressor 12a out of the compressors 12a and 12b, the compressed air compressed by the compressor 12a can be flowed into the pipe 36 and supplied to the air pressure device M1, bypassing the accumulator tank 13.

[0135] (2-3) Operation mode Table 2 shows the operation of each device in the CAES apparatus 1 in each operation mode in this embodiment.

[0136] [Table 2] In this embodiment, the operation modes in which only charging, discharging, or air pressure supply is performed, and the operation mode in which charging and air pressure supply are performed simultaneously are the same as those in the first embodiment. The difference from the first embodiment is that it is possible to perform an operation mode in which air pressure supply is performed through the pipe 35 while performing a discharging operation, and an operation mode in which air pressure supply is performed through the pipe 36 while performing a charging operation, etc.

[0137] (2-3a) Operation mode in which discharge and air pressure supply are performed simultaneously In the operation mode in which discharge and air pressure supply are performed simultaneously, the CAES apparatus 1 simultaneously performs the above-mentioned discharge operation and air pressure supply operation, and in this case, different accumulator tanks are used for the discharge operation and the air pressure supply operation.

[0138] For example, when accumulator tank 13a is at a high pressure near storage pressure P3 and accumulator tanks 13b and 13c are at a predetermined pressure P2, compressed air is supplied to expander 14a from accumulator tank 13a, which has a higher internal tank pressure. For air pressure supply, accumulator tank 13c, whose internal tank pressure has dropped to predetermined pressure P2, is used. The pressure in accumulator tank 13c gradually drops due to the air pressure supply. When the pressure in accumulator tank 13c drops to air usage pressure P1, the air pressure supply from accumulator tank 13c can no longer be continued, so the compressed air supply source is switched and compressed air is supplied to pneumatic device M1 from accumulator tank 13b.

[0139] In addition, by closing valve Ve and opening valve V35, compressed air from the same accumulator tank can be expanded and reduced in pressure by first-stage expander 14a, and the compressed air can be supplied to pneumatic equipment M1 via piping 35. In this case, if the pressure after first-stage expansion detected by pressure sensor Pe does not reduce to approximately predetermined pressure P2, valve Ve can be opened by adjusting its opening rather than fully closing, thereby driving expander 14b to adjust the rotation speed of generator 15b to generate electricity and adjust the pressure of the compressed air for pneumatic supply.

[0140] (2-3b) Operation mode in which charging and air pressure supply are performed simultaneously In the operation mode in which only air pressure is supplied via the pipe 36, as described above, the valve Vc is closed and the valve V36 is opened, and only the first-stage compressor 12a of the compressors 12a and 12b is driven. This allows the compressed air compressed to approximately a predetermined pressure P2 by the compressor 12a to be supplied to the pneumatic device M1 via the pipe 36 without being stored in the accumulator tank 13, while the pressure is appropriately monitored by the pressure sensor Pc.

[0141] In an operation mode in which air pressure is supplied via the pipe 36 while charging is being performed, both valves Vc and V36 are opened and the compressors 12a and 12b are driven. As a result, a portion of the compressed air compressed to approximately a predetermined pressure P2 by the compressor 12a is flowed through the pipe 36 and supplied to the pneumatic device M1, and at the same time, the remaining compressed air discharged from the compressor 12a is further compressed by the compressor 12b and stored in the accumulator tank 13.

[0142] Furthermore, in an operation mode in which air pressure is supplied via the pipe 36 while charging is being performed, the valve Vc is closed, and one of the valves Vc1, Vc2, and Vc3 connected to the accumulator tanks 13a, 13b, and 13c that has not reached the air working pressure P1 is sequentially opened, and then the valve V36 is opened, and the compressors 12a and 12b are driven. As a result, compressed air compressed to approximately the predetermined pressure P2 by the compressor 12a is flowed into the pipe 36 and supplied to the pneumatic device M1, and at the same time, compressed air in the accumulator tank 13 that has not yet reached the air working pressure P1 can be further compressed by the compressor 12b and stored at high pressure in the accumulator tank 13.

[0143] (2-4) Adjustment of power supply and demand The following describes the operation mode switching and power supply and demand adjustment of the CAES apparatus 1 of this embodiment. When switching modes, the operation / stop of each device and the opening and closing of valves are performed according to commands from the control device 70.

[0144] (2-4a) When power generation exceeds power demand When the power generation amount (W72) of renewable energy power generation devices such as solar power generation devices 2 and wind power generation devices 3 connected to the power transmission and distribution system 5 exceeds the power consumption amount (W71) of the factory M, and surplus power is generated, the CAES device 1 is operated in a charging operation mode, and the surplus power is stored as compressed air.

[0145] At this time, if the operation demand of the pneumatic device M1 is large and the amount of air pressure used is large, the CAES device 1 is operated in an operation mode in which charging and air pressure supply are performed simultaneously.

[0146] In an operating mode in which charging and air pressure supply are performed simultaneously, if a large amount of surplus electricity is generated, the compressors 12a and 12b must be driven mainly for charging, and therefore air pressure is supplied to the air pressure equipment M1 from the pressure accumulator tank 13.

[0147] When the amount of surplus electricity generated is small, the supply of air pressure from the accumulator tank 13 to the pneumatic equipment M1 is stopped, valve V36 is opened and valve Vc is closed, compressed air at a predetermined pressure P2 discharged from compressor 12a is supplied to the pneumatic equipment M1, and one of valves Vc1, Vc2, and Vc3 connected to the accumulator tank 13 that has not reached the air operating pressure P1 is sequentially opened, and the compressed air in the accumulator tank 13 is compressed to high pressure by compressor 12b and charged.

[0148] (2-4b) When power generation is below power demand When the power generation amount (W72) of renewable energy power generation devices such as solar power generation devices 2 and wind power generation devices 3 connected to the power transmission and distribution system 5 is less than the power consumption amount (W71) of the factory M, operation in three operating modes is possible.

[0149] When there is no request to operate the pneumatic device M1, the CAES device 1 operates in an operation mode in which only discharge is performed. The CAES device 1 operates in the operation mode in which discharge is performed, and generates electricity from the compressed air and supplies it to the power transmission and distribution system 5.

[0150] When there is a request to operate the pneumatic device M1, the CAES device 1 is operated in an operation mode in which only air pressure is supplied, or in an operation mode in which discharge and air pressure are supplied simultaneously, and compressed air is supplied to the pneumatic device M1.

[0151] Here, if there is a pressure accumulator tank whose pressure has been reduced to approximately a predetermined pressure P2, air pressure is supplied from the pressure accumulator tank at approximately the predetermined pressure P2 to the pneumatic equipment M1 without passing through the expander 14a, and compressed air is supplied to the expander 14a from another pressure accumulator tank whose storage pressure is close to P3, and while driving the generator 15a, air pressure reduced to the air usage pressure P1 is supplied to the pneumatic equipment M1 through the piping 35.

[0152] In this embodiment, if there is no pressure accumulator tank whose pressure has been reduced to approximately the predetermined pressure P2, high-pressure compressed air close to the storage pressure P3 is supplied from one of the pressure accumulator tanks 13a-13c to the expander 14a, and the expander 14a is driven to generate electricity, while the compressed air reduced in pressure by the expander 14a is supplied to the pneumatic equipment M1 via piping 35.

[0153] For example, when compressed air is supplied from the accumulator tank 13a, the pressure in the accumulator tank 13a is monitored by the pressure sensor P31, and when the pressure in the accumulator tank 13a drops to a predetermined pressure P2, the valve VL1 is closed and the valve V31 is opened, and the mode is switched to supply the compressed air, which has been reduced to the predetermined pressure P2, from the accumulator tank 13a to the pneumatic device M1 via the piping 31 without passing through the expander 14a. When the pressure in this tank drops to the air usage pressure P1, the mode is switched back to supply compressed air from another accumulator tank 13b or 13c to the expander 14a, and air pressure is supplied while driving the generator 15a.

[0154] (2-4c) Determining the operating mode To perform the above-described operation, the control device 70 must determine the operation mode to be selected and automatically control the electrically powered devices including the valves V31-V36, VL1-VL5, Vc1-Vc3, Ve, and Vc. The operation mode is determined according to the flow shown in FIG.

[0155] FIG. 6 is a flowchart showing an example of control of the CAES apparatus according to the second embodiment of the present invention.

[0156] The control flow diagram of Fig. 6 differs from the control flow diagram of the first embodiment of Fig. 2 in that step S201 is executed instead of step S106. In Fig. 6, the same steps as in Fig. 2 are denoted by the same reference numerals, and their explanation will be omitted.

[0157] When the power consumption (W71) of the factory M exceeds the power generation amount (W72) of the renewable energy power generation device, and when the power consumption (W71) of the factory M is balanced with the power generation amount (W72) of the renewable energy power generation device (YES in step S102), if there is a request to operate the pneumatic equipment M1 (YES in step S103), the control device 70 selects operation in a mode in which discharge and air pressure supply are performed simultaneously (step S201). At this time, the control device 70 supplies air pressure via the piping 35 while driving the expander 14a to perform expansion and power generation.

[0158] In this way, even when there is a request to operate the pneumatic device M1, the air pressure can be supplied while performing the discharging operation without operating the compressor for supplying the air pressure.

[0159] 7 and 8 show the changes in the pressure in the accumulator tank 13, the outputs of the compressor 12 and the expander 14, and the amount of electric power when the system is operated in this manner.

[0160] 7 and 8 are diagrams showing an example of the operation of the CAES apparatus according to the second embodiment of the present invention, in which Fig. 7 shows the change in the main time slot in the morning, and Fig. 8 shows the change in the main time slot in the afternoon.

[0161] In the flow shown in FIG. 6, the operating mode is switched by comparing the power generation amount (W72) of the renewable energy power generation device input from the power conditioner 4 with the power consumption amount (W71) of the factory M input from the power meter 71, but the switching may also be performed when the values ​​of W71 and W72 change beyond a predetermined threshold.

[0162] Alternatively, the switching may be performed when a predetermined time has elapsed since the values ​​of W71 and W72 have changed beyond a predetermined threshold.

[0163] Also, as shown in Figure 7, it is possible to prioritize pre-programmed operation modes depending on the time of day, for example, by giving priority to operation in charging mode during the late night hours from 2:00 to 5:00.

[0164] (2-5) Effects In this embodiment, the same effects as in the first embodiment can be obtained.

[0165] Additionally, in this embodiment, an operation mode can be performed in which the expander 14a is driven to perform expansion and power generation while air pressure is supplied through the piping 35. In this operation mode, when the pressure is reduced from the high-pressure accumulator tank 13 to the air pressure usage pressure P1 of the pneumatic device M1, the energy of the stored compressed air can be recovered by the expander 14a without loss.

[0166] Furthermore, an operation mode can be performed in which compressed air from the compressor 12a is supplied to the pneumatic device M1 through the piping 36. In the operation mode in which compressed air from the compressor 12a is supplied to the pneumatic device M1 through the piping 36, energy is required for the compressor 12a to compress the atmosphere to approximately a predetermined pressure P2, but at the same time, high-pressure compressed air can be stored in the accumulator tank, enabling greater adjustment operation. Therefore, energy loss due to air pressure supply can be reduced, and system efficiency (power recovery efficiency) can be improved compared to the first embodiment.

[0167] As described above, according to this embodiment, the compressed air stored in the accumulator tank 13 can be used for both power generation and air pressure supply without reducing the pressure more than necessary, and a CAES apparatus can be provided that has high system efficiency including air pressure supply and is capable of adjusting power supply and demand.

[0168] (Third embodiment) FIG. 9 is a schematic diagram showing an example of the configuration of a CAES apparatus according to the third embodiment of the present invention.

[0169] In FIG. 9, elements that are the same as or correspond to those in the embodiment already described are given the same reference numerals as in the previously described drawings, and descriptions thereof will be omitted as appropriate.

[0170] (3-1) CAES device The CAES apparatus 1 of this embodiment differs from the first embodiment in that it includes an air pressure supply unit 40 for supplying compressed air to the pneumatic equipment M1.

[0171] In this embodiment, the air pressure supply unit 40 includes an air pressure supply compressor 41 that is dedicated to supplying air pressure and is different from the compressor 12, and pipes 42 and 43 that connect the air pressure supply compressor 41 to the air pressure supply pipe 30. The pipe 42 connects the air pressure supply compressor 41 to an air pressure tank 44, and the pipe 43 connects the air pressure tank 44 to the pipe 34 of the air pressure supply pipe 30. A valve 45 is provided on the pipe 43. The air pressure supply compressor 41 is driven by a motor (electric motor) 46 that is driven by grid power, just like the compressors 12a and 12b.

[0172] In the air pressure supply unit 40, the air pressure supply compressor 41 draws in the atmosphere, compresses the atmosphere to the air pressure operating pressure P1 of the air pressure device M1 or to a predetermined pressure P2, sends the compressed air to the air pressure tank 44 via piping 42, and supplies the compressed air to the air pressure device M1 via piping 43 by opening and closing a valve 45.

[0173] Other hardware configurations of the CAES apparatus 1 of the third embodiment are similar to those of the first embodiment.

[0174] (3-2) Basic operation The operation of the CAES apparatus 1 of the third embodiment will be described. In this embodiment, the charging operation and discharging operation are the same as in the first embodiment, so the air pressure supply operation will be described here.

[0175] In this embodiment, as in the first embodiment, air pressure can be supplied to the pneumatic device M1 sequentially from the pressure accumulator tanks whose pressure has dropped to the predetermined pressure P2, and if there are multiple pressure accumulator tanks with pressures around the predetermined pressure P2, compressed air can be supplied to the pneumatic device M1 preferentially from the pressure accumulator tank with the lowest pressure.

[0176] Additionally, in this embodiment, in addition to air pressure supply from the accumulator tank 13, air pressure can also be supplied from the air pressure supply unit 40. When compressed air is supplied from the air pressure supply unit 40 to the pneumatic device M1, the valves V31-V33 are closed to block the air pressure supply from the accumulator tank 13, and the valve 45 of the air pressure supply unit 40 is opened to operate the air pressure supply compressor 41.

[0177] (3-3) Operation mode Table 3 shows the operation of each device in the CAES apparatus 1 in each operation mode in this embodiment.

[0178] [Table 3] In this embodiment as well, the operation modes that can be performed in the first embodiment can be performed with the valve 45 closed and the air pressure supply compressor 41 stopped.

[0179] In addition, in this embodiment, an operation mode in which only air pressure is supplied by the air pressure supply compressor 41, an operation mode in which air pressure is supplied by the air pressure supply compressor 41 while a charging operation is being performed, and the like can be implemented.

[0180] (3-3a) Operation mode with only air pressure supply In an operating mode in which only air pressure is supplied by the air pressure supply compressor 41, the compressors 12a, 12b and the expanders 14a, 14b are stopped, the valves V31-V33 are closed, and the valve 45 of the air pressure supply unit 40 is opened as described above to operate the air pressure supply compressor 41.

[0181] (3-3b) Operation mode in which charging and air pressure supply are performed simultaneously In an operating mode in which air pressure is supplied by the air pressure supply compressor 41 while charging, the compressors 12a, 12b and the air pressure supply compressor 41 are driven with the valves V31-V33 closed, so that the charging operation of storing compressed air by the compressors 12a, 12b and the air pressure supply operation by the air pressure supply unit 40 can be performed simultaneously.

[0182] (3-4) Adjustment of power supply and demand The following describes the operation mode switching and power supply and demand adjustment of the CAES apparatus 1 of this embodiment. When switching modes, the operation / stop of each device and the opening and closing of valves are performed according to commands from the control device 70.

[0183] (3-4a) When power generation exceeds power demand When the power generation amount (W72) of renewable energy power generation devices such as solar power generation devices 2 and wind power generation devices 3 connected to the power transmission and distribution system 5 exceeds the power consumption amount (W71) of the factory M, and surplus power is generated, the CAES device 1 is operated in a charging operation mode, and the surplus power is stored as compressed air.

[0184] At this time, if the operation demand of the pneumatic device M1 is large and the amount of air pressure used is large, the CAES device 1 is operated in an operation mode in which charging and air pressure supply are performed simultaneously.

[0185] In an operating mode in which charging and air pressure supply are performed simultaneously, if a large amount of surplus electricity is generated, the compressors 12a and 12b must be driven mainly for charging, and therefore, air pressure is supplied to the air pressure equipment M1 by the air pressure supply unit 40.

[0186] When the amount of surplus electricity generated is small, there is no need to drive both compressors 12a and 12b, so the air pressure supply by the air pressure supply unit 40 is stopped and switched to air pressure supply by the accumulator tank 13. The method of air pressure supply by the accumulator tank 13 is as already described. When the air pressure supply by the accumulator tank 13 is sufficient, the air pressure supply unit 40 is stopped, thereby making it possible to reduce the power demand used by the air pressure supply unit 40.

[0187] (3-4b) When power generation is below power demand When the power generation amount (W72) of renewable energy power generation devices such as solar power generation devices 2 and wind power generation devices 3 connected to the power transmission and distribution system 5 is less than the power consumption amount (W71) of the factory M, operation in three operating modes is possible.

[0188] When there is a request to operate the pneumatic equipment M1, the CAES device 1 operates in an operation mode that only supplies air pressure, supplies compressed air to the pneumatic equipment M1, and stops operation of the air pressure supply compressor 41. Since there is no longer any demand for electricity to produce compressed air in the factory M, the amount of electricity generated by the renewable energy power generation device and the amount of electricity used by the factory M are balanced at a value that is about 10-20% lower than when compressed air is produced in the factory M, and the scale of power generation by the renewable energy power generation device can be reduced.

[0189] When there is no request to operate the pneumatic device M1, the CAES device 1 operates in an operation mode in which only discharge is performed. The CAES device 1 operates in the operation mode in which discharge is performed, and generates electricity from the stored compressed air and supplies it to the power transmission and distribution system 5.

[0190] (3-4c) Determining the operating mode To perform the above-described operation, the control device 70 must determine the operation mode to be selected and automatically control the electrically powered devices including the valves V31-V33, V45, and VL1-VL5. The operation mode is determined according to the flow chart shown in FIG. 2, as in the first embodiment.

[0191] 10 and 11 show the changes in the pressure in the accumulator tank 13, the outputs of the compressor 12 and the expander 14, and the amount of electric power when the system is operated in this manner.

[0192] 10 and 11 are diagrams showing an example of the operation of the CAES apparatus according to the third embodiment of the present invention, in which Fig. 10 shows the change in the main time slot in the morning, and Fig. 11 shows the change in the main time slot in the afternoon.

[0193] In the flow shown in Figure 2, the operating mode is switched by comparing the power generation amount (W72) of the renewable energy power generation device input from the power conditioner 4 with the power consumption amount (W71) of the factory M input from the power meter 71, but the switching may also be performed when the values ​​of W71 and W72 change beyond a predetermined threshold.

[0194] Alternatively, the switching may be performed when a predetermined time has elapsed since the values ​​of W71 and W72 have changed beyond a predetermined threshold.

[0195] Also, as shown in Figure 10, it is possible to prioritize pre-programmed operation modes depending on the time of day, for example, by giving priority to operation in charging mode during the late night hours from 2:00 to 5:00.

[0196] (3-5) Effects In this embodiment, the same effects as in the first embodiment can be obtained.

[0197] Additionally, in this embodiment, an operation mode can be performed in which air pressure is supplied by the air pressure supply unit 40, the specifications of which are optimized for air pressure supply, and by stopping this operation when adjusting supply and demand, it is possible to adjust by reducing the amount of power used in the factory M. Therefore, it is possible to improve system efficiency (power recovery efficiency).

[0198] (Fourth embodiment) FIG. 12 is a schematic diagram showing an example of the configuration of a CAES apparatus according to the fourth embodiment of the present invention.

[0199] In FIG. 12, elements that are the same as or correspond to those in the embodiment already described are given the same reference numerals as in the previously described drawings, and descriptions thereof will be omitted as appropriate.

[0200] (4-1) CAES device The CAES apparatus 1 of this embodiment differs from the first embodiment in that it includes a water supply pump 50 that is connected to the pressure accumulator tank 13 and increases the tank pressure of the pressure accumulator tank 13.

[0201] Although FIG. 12 illustrates a configuration in which water is injected into the pressure accumulator tank 13c by the water supply pump 50, the configuration may be such that water can be injected from the water supply pump 50 into at least one of the pressure accumulator tanks 13a-31c.

[0202] A valve Vp is provided in the pipe 51 that connects the water supply pump 50 and the pressure accumulator tank 13c.

[0203] Other hardware configurations of the CAES apparatus 1 of the fourth embodiment are similar to those of the first embodiment.

[0204] (4-2) Basic operation The operation of the CAES apparatus 1 of the fourth embodiment will be described.

[0205] In this embodiment, for example, when the pressure of the accumulator tank 13 to be used for supplying air pressure is less than the predetermined pressure P2 or the air usage pressure P1 and air pressure cannot be supplied to the pneumatic equipment M1, the water supply pump 50 injects water into the accumulator tank 13 to increase the internal pressure of the accumulator tank 13, and the compressed air that is less than the predetermined pressure P2 can be pressurized and supplied to the pneumatic equipment M1.

[0206] Furthermore, for example, the pressure in the accumulator tank 13, which drops as air pressure is supplied, can be monitored by pressure sensors P31-P33, and when the pressure in the accumulator tank 13 drops to a predetermined pressure P2 or air pressure usage pressure P1 (or a set value set with a margin around these values), the water supply pump 50 can be driven to maintain the pressure in the accumulator tank 13 at a pressure at which air pressure can be supplied, and the air pressure supply can be continued.

[0207] In this case, the predetermined pressure P2 or the air pressure used pressure P1 (or a set value set with a margin around these values) can be used as a threshold value to feedback-control the driving and stopping of the water supply pump 50.

[0208] The air pressure supply from the accumulator tank 13 using the water supply pump 50 can be performed simultaneously with the charging operation and the discharging operation. For example, if the accumulator tanks 13a and 13b are at a high pressure of about storage pressure P3 while the accumulator tank 13c is below the predetermined pressure P2, the air pressure can be supplied from the accumulator tank 13c while discharging using the accumulator tank 13a and increasing the pressure with the water supply pump 50.

[0209] Furthermore, for example, when neither of the accumulator tanks 13b, 13c reaches the predetermined pressure P2, compressed air can be stored in the accumulator tank 13b, and the air pressure can be increased by the water supply pump 50 and supplied from the accumulator tank 13c.

[0210] Furthermore, if the pressure in the accumulator tank 13 is below the pressure that can be used for the discharging operation, the water supply pump 50 can be used to increase the pressure in the accumulator tank 13 to a pressure that can be used for the discharging operation.

[0211] The water injected into the accumulator tank 13 from the water supply pump 50 is appropriately drained from a drain pipe (not shown) when storing compressed air in the accumulator tank 13.

[0212] In addition to the air pressure supply operation and discharge operation using the water supply pump 50, the basic operations that can be performed in the first embodiment can also be performed in this embodiment.

[0213] (4-3) Operation mode Table 3 shows the operation of each device in the CAES apparatus 1 in each operation mode in this embodiment.

[0214] [Table 4] In this embodiment as well, the operation modes that can be performed in the first embodiment can be performed with the valve Vp closed and the feedwater pump 50 stopped.

[0215] Additionally, in this embodiment, in an operation mode in which an air pressure supply operation or a discharge operation is performed, the pressure in the accumulator tank 13 can be increased by the water supply pump 50.

[0216] (4-4) Adjustment of power supply and demand The operation mode switching and power supply and demand adjustment of the CAES apparatus 1 of this embodiment are similar to those of the first embodiment.

[0217] (4-5) Effects In this embodiment, the same effects as in the first embodiment can be obtained.

[0218] Additionally, in this embodiment, even if the pressure in the accumulator tank 13 is not sufficient to supply air pressure as described above, the pressure in the accumulator tank 13 can be increased by the water supply pump 50 to supply air pressure. In the operation mode in which the water supply pump 50 is driven, the power demand of the CAES1 increases, but because the water supply pump 50 is a device dedicated to supplying air pressure to the pneumatic device M1, the specifications can be optimized for air pressure supply, and a decrease in system efficiency (power recovery efficiency) can be suppressed.

[0219] (Fifth embodiment) FIG. 13 is a schematic diagram showing an example of the configuration of a CAES apparatus according to the fifth embodiment of the present invention.

[0220] In FIG. 13, elements that are the same as or correspond to those in the embodiment already described are given the same reference numerals as in the previously mentioned drawings, and descriptions thereof will be omitted as appropriate.

[0221] (5-1) CAES device The CAES apparatus 1 of this embodiment differs from the first to fourth embodiments in that the accumulator tank 13 includes a low-pressure accumulator tank 13L and a high-pressure accumulator tank 13H.

[0222] The low-pressure accumulator tank 13L is connected to the outlet of the compressor 12a, which is a low-pressure compressor, via pipes LL and L30. The pipe LL connects the low-pressure accumulator tank 13L to the air pressure supply pipe 30, and the pipe L30 connects the air pressure supply pipe 30 to the outlet of the compressor 12a.

[0223] The high-pressure accumulator tank 13H is connected to the pipe L6 via the pipe LH. The pipe LH is provided with a valve VH. If there is only one high-pressure accumulator tank 13H, the valve VH is not necessarily required.

[0224] The low-pressure accumulator tank 13L stores compressed air compressed by the compressor 12a at a pressure equal to or higher than the air pressure operating pressure P1 and equal to or lower than a predetermined pressure P2, and the high-pressure accumulator tank 13H stores compressed air compressed by the high-pressure compressor, compressor 12b, at a pressure higher than the predetermined pressure P2.

[0225] 13, only one low-pressure accumulator tank 13L and one high-pressure accumulator tank 13H are shown, but a plurality of each may be provided. The high-pressure accumulator tank 13H corresponds to the accumulator tank 13 (accumulator tanks 13a-13c) of the first embodiment.

[0226] Compressed air exceeding the predetermined pressure P2 of the high-pressure accumulator tank 13H is supplied to the expander 14, and compressed air having a pressure equal to or lower than the predetermined pressure P2 of the low-pressure accumulator tank 13L is supplied to the pneumatic device M1 via the pneumatic supply pipe 30. The pneumatic supply pipe 30 is provided with a valve V30.

[0227] In this embodiment, the pipes LL and LH are connected via a pipe L80 having a pressure reducing device 80, and the low-pressure accumulator tank 13L and the high-pressure accumulator tank 13H are connected via the pressure reducing device 80.

[0228] The pressure reducing device 80 is an element that reduces the pressure of compressed air exceeding a predetermined pressure P2 that flows from the high-pressure accumulator tank 13H side (high-pressure equipment E2 side) to the low-pressure accumulator tank 13L side (air pressure supply equipment E1 side) to a pressure below the predetermined pressure P2, and a pressure adjustment valve (pressure reducing valve) can be typically used. A closable type of pressure adjustment valve can also be used. Alternatively, the pressure reducing device 80 can be replaced by an orifice, a throttle (a section with a reduced flow area provided midway through the pipe L80), or other alternative means.

[0229] A valve V40 is provided in the pipe Lc1 that connects the compressor 12a and the compressor 12b.

[0230] Other hardware configurations of the CAES apparatus 1 of the fifth embodiment are similar to those of the first embodiment.

[0231] The configuration of this embodiment allows existing air pressure supply equipment to be applied to the CAES system. For example, a factory M may already have an air pressure supply equipment E1 that stores compressed air compressed by a low-pressure compressor 12a in a low-pressure accumulator tank 13L and supplies the compressed air from the low-pressure accumulator tank 13L to air pressure equipment M1. In this case, the CAES apparatus 1 of this embodiment can be constructed by utilizing the existing air pressure supply equipment E1 and additionally installing high-pressure equipment E2 (compressor 12b, heat storage unit 20, high-pressure accumulator tank 13H, expander 14, generator 15, etc.) downstream of compressor 12b, which is a high-pressure compressor, to the air pressure supply equipment E1.

[0232] (5-2) Basic operation The basic operations of the CAES apparatus 1 of this embodiment, specifically the charging operation, the discharging operation, and the air pressure supply operation, will be described in order.

[0233] (5-2a) Charging operation During charging operation to generate and store compressed air, the CAES apparatus 1 operates as follows. During charging operation, the valve VL5 of the pipe L5 of the heat exchanger 25 is typically closed. Furthermore, the valves VL4 and VH of the pipes L4 and LH are open. The pressure in the high-pressure accumulator tank 13H is assumed to be less than the storage pressure P3. In this state, the motors 11a and 11b are driven by input power from the power transmission and distribution system 5, and the compressors 12a and 12b are driven, whereby compressed air is sent to the high-pressure accumulator tank 13H in the same manner as in the first embodiment.

[0234] Thereafter, when the pressure in the high-pressure accumulator tank 13H detected by a pressure sensor (not shown) reaches the storage pressure P3, the valve VH of the high-pressure accumulator tank 13H is closed and the motor 11b is stopped to stop storing compressed air in the high-pressure accumulator tank 13H. The motor 11a can continue to be driven to supply air pressure.

[0235] Through the above operations, part of the grid power is converted into the energy of compressed air or heat storage medium and stored (charged) in the CAES device 1, similarly to the first embodiment.

[0236] In this embodiment, a part of the compressed air compressed by the compressor 12a, which is a low-pressure compressor, is sent to the low-pressure accumulator tank 13L and stored in the low-pressure accumulator tank 13L.

[0237] (5-2b) Discharge operation During discharge operation, in which compressed air is used to drive generators 15a and 15b to generate electricity, the CAES apparatus 1 operates as follows. During discharge operation, valve VL4 on pipe L4 of heat exchanger 24 is typically closed. The pressure in high-pressure accumulator tank 13H exceeds predetermined pressure P2. In this state, by opening valves VH and VL5 on pipes LH and L5, compressed air from high-pressure accumulator tank 13H is drawn into expanders 14a and 14b, where it is adiabatically expanded, driving expanders 14a and 14b and released into the atmosphere.

[0238] When the expanders 14a and 14b are driven by the two-stage expansion of the compressed air, the expanders 14a and 14b drive the generators 15a and 15b, respectively, and the power generation outputs of the generators 15a and 15b are supplied to the power transmission and distribution system 5 via the power conditioner 17.

[0239] By the above operation, the compressed air energy stored in the CAES apparatus 1 is regenerated and returned (discharged) to grid power, similarly to the first embodiment.

[0240] (5-2c) Air pressure supply operation In the CAES system 1 of this embodiment, the high-pressure equipment E2 downstream of the compressor 12b is not used for the air pressure supply operation. When the control device 70 opens the valve V30, compressed air compressed by the compressor 12a and stored in the low-pressure accumulator tank 13L at a predetermined pressure P2 or less is supplied to the pneumatic equipment M1 via the air pressure supply piping 30. Furthermore, when the compressed air stored in the low-pressure accumulator tank 13L falls below the air pressure use pressure P1, the control device 70 opens the pressure reducing device 80 to reduce the pressure of the compressed air in the high-pressure accumulator tank 13H and supply it to the low-pressure accumulator tank 13L.

[0241] When the compressed air stored in the low-pressure accumulator tank 13L and the high-pressure accumulator tank 13H falls below the air pressure use pressure P1, the control device 70 operates the compressor 12a and supplies air pressure from the compressor 12a to the pneumatic equipment M1 via the piping L30.

[0242] (5-3) Operation mode Table 5 shows the operation of each device in the CAES apparatus 1 in each operation mode in this embodiment.

[0243] [Table 5] The operation mode of the CAES apparatus 1 of this embodiment will be described.

[0244] (5-3a) Charging-only operation mode In the operation mode in which only charging is performed, the CAES apparatus 1 performs only the charging operation described above, in which compressed air is generated by the compressors 12a and 12b and stored in the high-pressure accumulator tank 13H and the low-pressure accumulator tank 13L.

[0245] (5-3b) Discharge-only operation mode In the operation mode in which only the discharge is performed, the CAES apparatus 1 performs only the above-mentioned discharge operation in which the generators 15a and 15b are driven by the compressed air stored in the high-pressure accumulator tank 13H to generate electricity.

[0246] (5-3c) Operation mode with only air pressure supply In the operation mode for only air pressure supply, the CAES apparatus 1 only supplies air pressure to the pneumatic device M1. There are two modes: air pressure supply mode A, in which compressed air from the low-pressure accumulator tank 13L is supplied to the pneumatic device M1, and air pressure supply mode B, in which the compressor 12a is operated to supply air from the compressor 12a to the pneumatic device M1 via L30.

[0247] (5-3d) Operation mode in which charging and air pressure supply are performed simultaneously In an operation mode in which charging and air pressure supply are performed simultaneously, the CAES apparatus 1 simultaneously performs the charging operation and the air pressure supply operation. In this embodiment, the charging operation and the air pressure supply operation are performed in parallel using the high-pressure accumulator tank 13H and the low-pressure accumulator tank 13L, which are independent of each other.

[0248] (5-3e) Operation mode in which discharge and air pressure supply are performed simultaneously In the operating mode in which discharge and air pressure supply are performed simultaneously, the CAES device 1 can be operated in two ways: one in which the above-mentioned discharge operation and air pressure supply operation are performed simultaneously, and one in which, during the above-mentioned discharge operation, valve V30 is opened and the compressed air in the high-pressure accumulator tank 13H is depressurized by the pressure reducing device 80 and supplied to the air pressure equipment M1.

[0249] However, in this embodiment, the compressed air compressed by the compressor 12a and stored in the low-pressure accumulator tank 13L at a pressure equal to or lower than a predetermined pressure P2 is not supplied to the pneumatic equipment M1, but the compressed air in the high-pressure accumulator tank 13H is used, and the charging operation and the air pressure supply operation are performed in parallel.

[0250] (5-4) Adjustment of power supply and demand In the CAES device 1 of this embodiment, when the power generation amount (W72) of a renewable energy power generation device such as a solar power generation device 2 or a wind power generation device 3 connected to the power transmission and distribution system 5 exceeds the power consumption amount (W71) of the factory M and surplus power is generated, the device is operated in an operating mode for charging.

[0251] Furthermore, when the power generation amount (W72) of renewable energy power generation devices such as the solar power generation device 2 and the wind power generation device 3 connected to the power transmission and distribution system 5 is lower than the power consumption amount (W71) of the factory M, the CAES device 1 can operate in two operation modes. That is, when there is a request to operate the pneumatic device M1, the CAES device 1 operates in an operation mode in which only air pressure is supplied, and when there is no request to operate the pneumatic device M1, the CAES device 1 operates in an operation mode in which only discharge is performed.

[0252] When the power generation amount (W72) of renewable energy power generation devices such as solar power generation device 2 and wind power generation device 3 is less than the power consumption amount (W71) of factory M, there is a request to operate pneumatic equipment M1, and the pressure in low-pressure accumulator tank 13L drops to air usage pressure P1, the CAES device 1 operates in an operating mode that supplies the stored air pressure in high-pressure accumulator tank 13H.

[0253] (5-4a) Determining the operating mode To perform the above-described operation, the control device 70 must determine the operation mode to be selected and automatically control the electrically powered devices including the valves V30, V40, VL4-VL5, and the pressure reducing device 80. The operation mode is determined according to the flow shown in FIG.

[0254] FIG. 14 is a flowchart showing an example of control of the CAES apparatus according to the fifth embodiment of the present invention.

[0255] First, as described in the explanation of "power supply and demand adjustment" in the first embodiment and the like, it is necessary to determine the magnitude relationship between the amount of power generated by the renewable energy power generation device and the amount of power used by the factory M.

[0256] The control device 70 determines whether the amount of power consumption (W71) of the factory M exceeds (or is balanced with) the amount of power generated by the renewable energy power generation device (W72) (step S501). This can be determined by the control device 70 from the amount of power consumption of the factory M input from the wattmeter 71 and the amount of power generated by the renewable energy power generation device input from the power conditioner 4.

[0257] If the power consumption (W71) of the factory M is lower than the power generation (W72) of the renewable energy power generation device (NO in step S501), the control device 70 determines whether there is a request to operate the pneumatic equipment M1 by checking whether the pressure (P31) of the low-pressure accumulator tank 13L is lower than the pneumatic usage pressure P1 (step S502).

[0258] If the pressure (P31) of the low-pressure accumulator tank 13L is not lower than the air pressure operating pressure P1 (NO in step S502), the control device 70 determines that there is no request to operate the air pressure device M1 and selects an operating mode for performing charging operation (step S503).

[0259] On the other hand, if the pressure (P31) of the low-pressure accumulator tank 13L is lower than the air usage pressure P1 (YES in step S502), the control device 70 determines that there is a request to operate the air pressure device M1, and selects operation in air pressure supply mode B, in which the compressor 12a is operated to supply air pressure from the compressor 12a via L30 (step S504).

[0260] On the other hand, if the power consumption (W71) of the factory M exceeds the power generation amount (W72) of the renewable energy power generation device, and if the power consumption (W71) of the factory M is balanced with the power generation amount (W72) of the renewable energy power generation device (YES in step S501), the control device 70 determines whether there is a request to operate the pneumatic equipment M1 by checking whether the pressure (P31) of the low-pressure accumulator tank 13L is lower than the air usage pressure P1 (step S505).

[0261] If the pressure (P31) of the low-pressure accumulator tank 13L is not lower than the air pressure operating pressure P1 (NO in step S505), the control device 70 determines that there is no request to operate the pneumatic device M1, and operates it in an operation mode that only discharges air (step S506).

[0262] On the other hand, if the pressure (P31) of the low-pressure accumulator tank 13L is lower than the air operating pressure P1 (YES in step S505), the control device 70 determines that there is a request to operate the air equipment M1, and checks whether the pressure (P32) of the high-pressure accumulator tank 13H is higher than the pressure (P31) of the low-pressure accumulator tank 13L (step S507).

[0263] If the pressure (P32) of the high-pressure accumulator tank 13H exceeds the pressure (P31) of the low-pressure accumulator tank 13L (YES in step S507), the control device 70 opens the pressure reducing device 80, reduces the pressure of the compressed air stored in the high-pressure accumulator tank 13H and supplies it to the low-pressure accumulator tank 13L, and selects operation in air pressure supply mode A in which the compressed air in the low-pressure accumulator tank 13L is supplied to the pneumatic equipment M1 (step S510).

[0264] On the other hand, if the pressure (P32) of the high-pressure accumulator tank 13H is equal to or lower than the pressure (P31) of the low-pressure accumulator tank 13L (NO in step S507), the control device 70 selects operation in air pressure supply mode B, in which the compressor 12a is operated to supply air pressure from the compressor 12a (step S504).

[0265] As described above, in this embodiment, in the operation mode in which the charging operation is performed, the operation request for the pneumatic device M1 is determined by comparing the pressure (P32) of the high-pressure accumulator tank 13H, the pressure (P31) of the low-pressure accumulator tank 13L, and the air pressure usage pressure P1, and if there is a request to operate the pneumatic device M1, the discharging operation is not performed, and priority is given to operation in an operation mode in which only air pressure is supplied. Also, if the compressed air in the low-pressure accumulator tank 13L is lower than the air pressure usage pressure P1, compressed air compressed by the compressor 12a is supplied to the pneumatic device M1 under air pressure.

[0266] 15 and 16 show the changes in the pressure of the accumulator tank 13, the outputs of the compressor 12 and the expander 14, and the amount of electric power when the system is operated in this manner.

[0267] 15 and 16 are diagrams showing an example of the operation of the CAES apparatus according to the fifth embodiment of the present invention, in which Fig. 15 shows the change in the main time slot in the morning, and Fig. 16 shows the change in the main time slot in the afternoon.

[0268] In the flow shown in Figure 14, the operating mode is switched by comparing the power generation amount (W72) of the renewable energy power generation device input from the power conditioner 4 with the power consumption amount (W71) of the factory M input from the power meter 71, but the switching may also be performed when the values ​​of W71 and W72 change beyond a predetermined threshold.

[0269] Alternatively, the switching may be performed when a predetermined time has elapsed since the values ​​of W71 and W72 have changed beyond a predetermined threshold.

[0270] Also, as shown in FIG. 15, it is possible to operate the vehicle in a pre-programmed operating mode by giving priority to a certain time period, for example, by operating in charging mode during the late night hours from 2:00 to 5:00.

[0271] (5-5) Effects By supplying compressed air used in the factory M from the CAES apparatus 1, it is possible to adjust the power supply and demand of the factory and rationally level out the power, as in the first embodiment.

[0272] Furthermore, in this embodiment, compressed air from the compressor 12a can be supplied to the pneumatic equipment M1, as in the second embodiment. By supplying compressed air from the compressor 12a to the pneumatic equipment M1, the charge amount of the CAES apparatus 1 decreases compared to when only charging is performed. However, since it is sufficient to compress the atmosphere to approximately a predetermined pressure P2 using the compressor 12a, the amount of energy used for supplying air pressure can be reduced, enabling highly efficient operation. Since energy loss due to air pressure supply can be reduced, the system efficiency (power recovery efficiency) of the CAES apparatus 1 is improved.

[0273] This embodiment is similar to the second embodiment in that the compressed air compressed by the compressor 12a is supplied to the pneumatic equipment M1 by bypassing the compressor 12b, which is a high-pressure compressor, but differs from the second embodiment in that the compressed air compressed by the compressor 12a, which is a low-pressure compressor, can be stored in the low-pressure accumulator tank 13L.

[0274] In addition, the part that performs the air pressure supply operation (air pressure supply equipment E1) and the part that performs the charging operation and discharging operation (high voltage equipment E2) are separated into an upstream and downstream stage, and each can be operated essentially independently.

[0275] In addition, in the fifth embodiment, if the factory M is equipped with an existing air pressure supply facility E1, the high-pressure facility E2 can be added to the existing air pressure supply facility E1 to ensure the functionality of CAES, which has the great advantage of allowing the existing facility to be utilized without waste.

[0276] (Sixth embodiment) FIG. 17 is a schematic diagram showing an example of the configuration of a CAES apparatus according to the seventh embodiment of the present invention.

[0277] In FIG. 17, elements that are the same as or correspond to those in the previously described embodiment are given the same reference numerals as in the previously described drawings, and descriptions thereof will be omitted as appropriate.

[0278] (6-1) CAES device The CAES apparatus 1 of this embodiment differs from the fifth embodiment in that a pipe 60 that connects the compressor 12a, which is a low-pressure compressor, and the pipe Lc2 is provided instead of the pipe L30 that connects the compressor 12a, which is a low-pressure compressor, and the air pressure supply pipe 30. In other words, the compressor 12a and the low-pressure accumulator tank 13L are not directly connected.

[0279] The pipe 60 is provided with a valve V41, which is an electromagnetic valve that is opened and closed by the control device .

[0280] Other hardware configurations of the CAES apparatus 1 of the sixth embodiment are similar to those of the fifth embodiment.

[0281] This embodiment is common to the fifth embodiment in that it includes a high-pressure accumulator tank 13H and a low-pressure accumulator tank 13L as accumulator tanks, and that the low-pressure accumulator tank 13L is connected to the high-pressure accumulator tank 13H via a pressure reducing device 80 and is also connected to pneumatic equipment M1 via an air pressure supply pipe 30.

[0282] (6-2) Basic operation In this embodiment, the high-pressure accumulator tank 13H stores compressed air compressed by the compressor 12 (compressors 12a and 12b) to a pressure exceeding a predetermined pressure P2. The low-pressure accumulator tank 13L stores compressed air that is stored in the high-pressure accumulator tank 13H or discharged from the compressor 12b and exceeds the predetermined pressure P2, and is depressurized by the decompression device 80 to a pressure equal to or lower than the predetermined pressure P2.

[0283] Compressed air from the high-pressure accumulator tank 13H is supplied to the expander 14. Compressed air decompressed by the pressure reducing device 80, that is, compressed air stored in the low-pressure accumulator tank 13L, or compressed air supplied from the high-pressure accumulator tank 13H or the compressor 12b via the pressure reducing device 80, is supplied to the pneumatic equipment M1 via the air pressure supply piping 30.

[0284] When the compressed air stored in the low-pressure accumulator tank 13L and the high-pressure accumulator tank 13H falls below the air pressure usage pressure P1, the control device 70 operates the compressor 12a, opens the valves V41, VL4 and the pressure reducing device 80, and supplies air pressure from the compressor 12a to the pneumatic equipment M1.

[0285] (6-3) Operation mode Table 5 shows the operation of each device in the CAES apparatus 1 in each operation mode in this embodiment.

[0286] [Table 6] The operating mode implemented in this embodiment differs from the fifth embodiment in that in air pressure supply mode B, the compressor 12a is operated and the valves V41, VL4 and the pressure reducing device 80 are opened, so that air is supplied from the compressor 12a to the air pressure device M1 via L60.

[0287] (6-4) Adjustment of power supply and demand The operation mode switching and power supply and demand adjustment of the CAES apparatus 1 of this embodiment are similar to those of the fifth embodiment.

[0288] (6-5) Effects In the present embodiment, compared to the fifth embodiment, all of the compressed air compressed by the compressor 12 (compressors 12a, 12b) passes through the heat exchanger 24, so that the thermal energy of the compressed air for air pressure supply purposes can also be recovered, and thermal efficiency can be improved.

[0289] (Seventh embodiment) (7-1) LAES device 18 shows a schematic configuration diagram of an LAES apparatus according to a seventh embodiment of the present invention. Similar to the CAES apparatus 1 according to the first embodiment, the LAES apparatus 7 according to the seventh embodiment is an apparatus that levels the power (grid power) of a power transmission and distribution system 5 to which renewable energy power generation apparatuses such as photovoltaic power generation apparatuses 2 and wind power generation apparatuses 3 are connected.

[0290] When the amount of power generated by the renewable energy power generation device is large compared to the amount of power used in the factory M, the LAES device 7 stores (charges) a portion of the grid power as energy in the form of liquid air obtained by liquefying compressed air. Also, when the amount of power generated by the renewable energy power generation device is small compared to the amount of power used in the factory M, the LAES device 7 vaporizes the stored liquid air, generates power with the high-pressure compressed air, and returns (discharges) the power to the power transmission and distribution system 5. Also, the LAES device 7 can supply the vaporized compressed air to pneumatic equipment M1 that is driven by air pressure in the factory M.

[0291] Below, only the differences in configuration from the first embodiment will be explained.

[0292] In the LAES device 7, the compressor-expander unit 10 and the liquefaction unit 90 are connected by a pipe L7, and the pipe L7 branches off from a pipe L4 connected to the compressed air outlet of the heat exchanger 24.

[0293] (7-1a) Liquefaction unit The air compressed in multiple stages by the compressors 12a and 12b passes through the heat exchangers 24a and 24b, and then through the pipe L7 to flow into the boost compressor 99. In the boost compressor 99, the compressed air is pressurized for liquefaction, and the compressed air, which has now reached a higher pressure, releases heat to the surroundings and is cooled to approximately room temperature before flowing into the heat exchanger 91.

[0294] In the heat exchanger 91, the incoming compressed air is cooled to about -160°C and liquefied by exchanging heat with the already cooled heat storage medium inside the heat exchanger 91. The liquefied air passes through the pressure reducing valve V95, where it is further decompressed and cooled, and then stored in the pressure accumulator tank 98.

[0295] In the accumulator tank 98, the air decompressed by the pressure reducing valve V95 is separated into gas and liquid, and the gaseous air passes through the pressure reducing valve V94 and returns to the heat exchanger 91. In the heat exchanger 91, this gaseous air exchanges heat with the compressed air flowing in from the boost compressor 99 to cool the compressed air, and then returns to the inlet of the boost compressor 99, where it is compressed again and liquefied.

[0296] A pressure sensor P91 is provided in the pipe from the accumulator tank 98 to the pump 92, and a pressure sensor P92 is provided in the pipe from the heat exchanger 91 to the valve VL9.

[0297] Pressure sensor P91 detects the pressure in accumulator tank 98, and pressure sensor P92 detects the supply pressure of compressed air from liquefaction unit 90. These pressure sensors P91 and P92 make it possible to monitor the pressure in each part of the system of liquefaction unit 90. Furthermore, based on the pressures detected by these pressure sensors P91 and P92, liquefaction unit 90 can automatically control the opening and closing of pressure reducing valves V93-V95 and valves VL8 and VL9.

[0298] In the accumulator tank 98, the liquid air is stored at a pressure of about 1.5 to 2 MPa.

[0299] The control device 70 is connected to pressure sensors P31-P34, P91, P92, Pc, and Pe, a power conditioner 4, and a power meter 71 of factory M (which may be a computer in the control room of factory M, etc.), and inputs data such as the pressure detected by the pressure sensors P31-P34, P91, P92, Pc, and Pe, the power generation amount from a power meter 72 that measures the power generation amount of the renewable energy power generation device, and the power demand of factory M (power demand for the entire factory M, power demand for the pneumatic system).

[0300] The control device 70 is a computer that executes a control program and the like for the LAES device 7. The control device 70 can output open / close commands to the valves V30-V34 and the pressure reducing valves V93-V95, VL1-VL5, VL8, and VL9, start commands / stop commands / rotation speed commands to the motors 11a and 11b, the boost compressor 99, and the pumps 28 and 29, and further, rotation speed commands and power generation output commands to the generators 15a and 15b.

[0301] (7-2) Basic operation The basic operations of the LAES device 7, specifically the charging operation, discharging operation, and air pressure supply operation, will be explained in order.

[0302] (7-2a) Charging operation During charging operation to generate and store compressed air, the LAES device 7 operates as follows. During charging operation, typically, the valves V31-V33 of the air pressure supply pipe 30 and the valve VL5 of the pipe L5 of the heat exchanger 25 are closed. Also, the valve VL4 of the pipe L4 of the heat exchanger 24 is open.

[0303] First, motors 11a and 11b are driven by the input power from the power transmission and distribution system 5. The compressors 12a and 12b are driven by the motors 11a and 11b, and two-stage compression is performed by the compressors 12a and 12b. In the compressor 12a, air is inhaled from the suction port and the first-stage adiabatic compression is performed. In the compressor 12b, the compressed air discharged from the discharge port of the compressor 12a is inhaled and the second-stage adiabatic compression is performed, and the compressed air at high pressure and high temperature is discharged. This high-temperature and high-pressure compressed air flows into the heat exchangers 24a and 24b, and exchanges heat with the low-temperature heat storage medium supplied from the low-temperature heat storage tank 22 to the heat exchangers 24a and 24b by the pump 29. By this heat exchange, the low-temperature heat storage medium becomes high temperature and is stored in the high-temperature heat storage tank 21. On the other hand, the compressed air reduces its temperature and flows into and is stored in the accumulator tank 13.

[0304] At that time, the compressed air is stored in the accumulator tanks 13a, 13b, and 13c in this order, for example. That is, when the pressures of all the accumulator tanks 13a, 13b, and 13c are less than a predetermined storage pressure P3 (for example, about 1.2 MPa, P1 < P2 < P3), the valves VL2 and VL3 of the accumulator tanks 13b and 13c are closed, the valve VL1 of the accumulator tank 13a is opened, and the compressed air is sent into the accumulator tank 13a.

[0305] After that, when the pressure of the accumulator tank 13a detected by the pressure sensor P31 reaches the storage pressure P3, the valves VL1 and VL3 of the accumulator tanks 13a and 13c are closed, the valve VL2 of the accumulator tank 13b is opened, and the storage destination of the compressed air is switched to the accumulator tank 13b.

[0306] When the pressure of the accumulator tank 13b detected by the pressure sensor P32 reaches the storage pressure P3, the valves VL1 and VL2 of the accumulator tanks 13a and 13b are closed, the valve VL3 of the accumulator tank 13c is opened, and the storage destination of the compressed air is switched to the accumulator tank 13c.

[0307] When the pressure in the accumulator tank 13c detected by the pressure sensor P33 reaches the storage pressure P3, the valve VL3 is closed and the valve VL8 is opened to supply compressed air to the boost compressor 99. The air compressed in the boost compressor 99 releases heat to the surroundings, is cooled to about room temperature, and then flows into the heat exchanger 91. The compressed air that has flowed into the heat exchanger 91 exchanges heat with the already cooled heat storage medium in the heat exchanger 91, where it is cooled to about -160°C and liquefied.

[0308] The air liquefied in the heat exchanger 91 passes through pressure reducing valve V95, where it is further decompressed and cooled, and then stored in the accumulator tank 98. In the accumulator tank 98, the air decompressed by pressure reducing valve V95 is separated into gas and liquid, and the gaseous air passes through pressure reducing valve V94 and returns to the heat exchanger 91. In the heat exchanger 91, this gaseous air exchanges heat with compressed air flowing in from the boost compressor 99 to cool the compressed air, and then returns to the inlet of the boost compressor 99, where it is compressed again and liquefied.

[0309] The pressure in the accumulator tank 98 is detected by a pressure sensor P91 and controlled by pressure reducing valves V94 and V95 to maintain an appropriate storage pressure. In the accumulator tank 98, the temperature of the stored liquid air is adjusted by controlling the pressure.

[0310] Through the above operation, part of the grid power is converted into the energy of the compressed air, liquid air, and heat storage medium, and is stored (charged) in the LAES device 7.

[0311] (7-2b) Discharge operation During discharge operation, in which compressed air is used to drive the generator to generate electricity, the LAES device 7 operates as follows. During discharge operation, typically, valves V31-V33 of the air pressure supply pipe 30, valves VL1-VL3 and VL8 connected to the accumulator tank 13, and valve VL4 of the pipe L4 of the heat exchanger 24b are closed. Also, valves VL5 and VL9 of the pipe L5 of the heat exchanger 25a are open.

[0312] First, liquid air stored in an accumulator tank 98 is flowed into a heat exchanger 91 by a pump 92 through a pressure reducing valve V93. The liquid air that flows into the heat exchanger 91 exchanges heat with the heat storage medium in the heat exchanger 91, rising in temperature to approximately room temperature, vaporizing, and flowing out as compressed air. This compressed air then passes through valves VL9 and VL5 and flows into the heat exchanger 25a via pipe L5. The compressed air passes through the heat exchangers 25a and 25b and is adiabatically expanded in the expanders 14a and 14b, thereby driving these expanders. The pressure of the compressed air flowing out of the heat exchanger 91 is detected by a pressure sensor P92 and controlled by the pressure reducing valve V93.

[0313] The compressed air that flows into the heat exchangers 25a and 25b exchanges heat with a high-temperature heat storage medium that is supplied to the heat exchangers 25a and 25b from the high-temperature side heat storage tank 21 by the pump 28. The high-temperature heat storage medium becomes cold through this heat exchange and is stored in the low-temperature side heat storage tank 22.

[0314] Meanwhile, the compressed air increases in temperature and is drawn into expanders 14a and 14b where it undergoes adiabatic expansion, driving generators 15a and 15b. The compressed air that has undergone the first stage adiabatic expansion in expander 14a is drawn into expander 14b where it undergoes the second stage adiabatic expansion, driving expander 14b. The low-temperature, low-pressure air that has undergone the adiabatic expansion in expander 14b is released into the atmosphere from the discharge port of expander 14b.

[0315] When the expanders 14a and 14b are driven by the two-stage expansion of the compressed air, the expanders 14a and 14b drive the generators 15a and 15b, respectively, and the power generation outputs of the generators 15a and 15b are supplied to the power transmission and distribution system 5 via the power conditioner 17.

[0316] When the liquid air stored in the accumulator tank 98 is used up, the valve VL9 is closed and the valves VL1 to VL3 connected to the accumulator tank 13 are sequentially opened, thereby supplying the compressed air stored in the accumulator tank 13 to the heat exchanger 25a. At this time, the compressed air of the accumulator tank with the higher pressure is given priority. When all the accumulator tanks have the stored pressure P3, the compressed air is supplied in a predetermined order (for example, the order of the accumulator tanks 13a, 13b, and 13c).

[0317] For example, when the pressure accumulator tanks 13a, 13b, and 13c are all at storage pressure P3, the valves VL2 and VL3 of the pressure accumulator tanks 13b and 13c are closed, and the valve VL1 of the pressure accumulator tank 13a is opened, sending the compressed air from the pressure accumulator tank 13a to the heat exchanger 25a.

[0318] Thereafter, when the pressure in the accumulator tank 13a detected by the pressure sensor P31 drops to a predetermined pressure P2, the valves VL1 and VL3 of the accumulator tanks 13a and 13c are closed, the valve VL2 of the accumulator tank 13b is opened, and the source of compressed air to the heat exchanger 25 is switched to the accumulator tank 13b.

[0319] When the pressure in the accumulator tank 13b detected by the pressure sensor P32 drops to a predetermined pressure P2, the valves VL1 and VL2 of the accumulator tanks 13a and 13b are closed, the valve VL3 of the accumulator tank 13c is opened, and the source of compressed air to the heat exchanger 25 is switched to the accumulator tank 13c.

[0320] When the pressure in the accumulator tank 13c detected by the pressure sensor P33 drops to a predetermined pressure P2, the valve VL3 is closed and the supply of compressed air from the accumulator tank 13c to the heat exchanger 25 is stopped.

[0321] By the above operation, the compressed air energy stored in the LAES device 7 is regenerated and returned (discharged) to grid power.

[0322] (7-2c) Air pressure supply operation During the air pressure supply operation for supplying compressed air at approximately a predetermined pressure P2 to the pneumatic device M1, the LAES device 7 operates as follows.

[0323] During air pressure supply operation, compressed air is supplied to the pneumatic device M1 in order from the accumulator tanks 13a-13c whose pressure has dropped to a predetermined pressure P2 (principally, equal to or greater than the air working pressure P1). Alternatively, if there are multiple accumulator tanks with a pressure of about the predetermined pressure P2, compressed air is supplied to the pneumatic device M1 in order from the accumulator tank with the lowest pressure.

[0324] For example, when the pressure in the accumulator tanks 13a and 13b is high and close to the storage pressure P3, and the pressure in the accumulator tank 13c is close to the predetermined pressure P2, first, the valve V33 on the pipe 33 of the air pressure supply pipe 30 corresponding to the accumulator tank 13c is opened, and the valve VL3 on the pipe L3 of the accumulator tank 13c is closed, and the compressed air stored in the accumulator tank 13c is supplied to the pneumatic equipment M1.

[0325] At this time, the valves V31 and V32 corresponding to the accumulator tanks 13a and 13b of the air pressure supply pipe 30 are closed. In this way, by switching the valves V31-V33 and VL1-VL3 between open and closed, compressed air at approximately a predetermined pressure P2 is supplied from the accumulator tanks 13a-13c to the pneumatic device M1 as appropriate.

[0326] When the pressures in all of the accumulator tanks 13 fall below the air operating pressure P1, valve VL9 is opened to supply the stored liquid air. At this time, liquid air stored in accumulator tank 98 is flowed into heat exchanger 91 by pump 92 through pressure reducing valve V93. The liquid air that flows into heat exchanger 91 exchanges heat with the heat storage medium inside heat exchanger 91, raising its temperature to approximately room temperature and vaporizing. The naturalized compressed air passes through valve VL9 and flows into air supply piping 30 via either valves V31-V33 or VL1-VL3, and is supplied to pneumatic equipment M1. The pressure of the compressed air flowing out of heat exchanger 91 is detected by pressure sensor P92 and controlled by pressure reducing valve V93.

[0327] In addition, when multiple accumulator tanks are provided like the LAES device 7 of this embodiment, compressed air is typically supplied to the pneumatic device M1 from any one of the accumulator tanks. For example, when compressed air is supplied to the pneumatic device M1 from the accumulator tank 13c and the pressure in the accumulator tank 13c falls below the air operating pressure P1, if the pressure in either the accumulator tank 13a or 13b is approximately a predetermined pressure P2, the supply source of compressed air to the pneumatic device M1 is switched to the accumulator tank 13a or 13b by operating a valve.

[0328] (7-3) Operation mode Table 7 shows the operation of each device of the LAES device 7 in each operation mode in this embodiment.

[0329] [Table 7] Regarding the operation mode of the LAES device 7, only differences in the configuration from the first embodiment will be described.

[0330] (7-3a) Charging-only operation mode In the operation mode in which only charging is performed, only the charging operation described above is performed.

[0331] (7-3b) Discharge-only operation mode In the operation mode in which only discharging is performed, only the discharging operation described above is performed.

[0332] (7-3c) Operation mode with only air pressure supply In the operation mode in which only air pressure is supplied, only the air pressure supply operation described above is performed.

[0333] (7-3d) Operation mode in which charging and air pressure supply are performed simultaneously In the operation mode in which charging and air pressure supply are performed simultaneously, the LAES device 7 simultaneously performs the charging operation and the air pressure supply operation. At this time, different accumulator tanks are used for the charging operation and the air pressure supply operation.

[0334] For example, as in the case of charging the pressure accumulator tank 98 described above, while storing compressed air in a liquefied form, among the valves V31-V33 of the air pressure supply pipe 30, the valve (e.g., V33) of the air pressure supply pipe connected to the tank with the lowest storage pressure is opened, and the rest are closed.

[0335] Compression is performed by the compressors 12a and 12b, and the compressed air is sent to the liquefaction unit 90 through the pipe L7 and then stored in the accumulator tank 98.

[0336] At the same time, valve V33 of pipe 33 of air pressure supply pipe 30 corresponding to accumulator tank 13c is opened, and compressed air stored in accumulator tank 13c is supplied to pneumatic device M1. At this time, valves V31 and V32 corresponding to accumulator tanks 13a and 13b of air pressure supply pipe 30 are controlled, and valves V31-V33 are switched between open and closed states depending on the pressure of accumulator tank 13, and compressed air at approximately a predetermined pressure P2 is supplied from accumulator tanks 13a-13c to pneumatic device M1 as appropriate.

[0337] By the above operation, discharge and air pressure supply operations are performed simultaneously.

[0338] (7-3e) Operation mode in which discharge and air pressure supply are performed simultaneously In the operation mode in which discharge and air pressure supply are performed simultaneously, the LAES device 7 simultaneously performs the above-mentioned discharge operation and air pressure supply operation. At this time, different accumulator tanks are used for the discharge operation and the air pressure supply operation.

[0339] For example, liquid air in the accumulator tank 98 is vaporized and sent to the heat exchanger 25a, where it exchanges heat with a high-temperature heat storage medium supplied from the high-temperature side heat storage tank 21 to the heat exchangers 25a and 25b by the pump 28, raising the temperature of the compressed air, which is then drawn into the expanders 14a and 14b where it undergoes adiabatic expansion and drives the generators 15a and 15b. The power output of the generators 15a and 15b is supplied to the power transmission and distribution system 5 via the power conditioner 17.

[0340] At the same time, the tank with the lowest pressure among the accumulator tanks 13, which stores compressed air at approximately the predetermined pressure P2, opens a valve (one of V31-V33) on the pipe connected to the air pressure supply pipe 30, and supplies the compressed air stored in the accumulator tank 13 to the pneumatic device M1. For example, when supplying air from the accumulator tank 13c, the valves V31 and V32 corresponding to the accumulator tanks 13a and 13b on the air pressure supply pipe 30 are closed. In this way, by switching the valves V31-V33 open and closed, compressed air at approximately the predetermined pressure P2 is supplied appropriately from the accumulator tanks 13a-13c to the pneumatic device M1.

[0341] For the air pressure supply, the accumulator tanks whose internal pressure has dropped to a predetermined pressure P2 are used in sequence. The pressure in the accumulator tank 13 gradually drops due to the air pressure supply. When the pressure in the accumulator tank 13 drops to the air pressure usage pressure P1, the air pressure supply from the accumulator tank 13 can no longer be continued, so compressed air is also supplied to the pneumatic device M1, using the liquid air in the accumulator tank 98 that is being used for the discharging operation.

[0342] Furthermore, when it is expected that a large amount of compressed air will be used in the pneumatic device M1, the discharge operation is terminated, and an appropriate valve connected to the air pressure supply pipe 30 is selected and opened, switching the liquid air in the accumulator tank 98 from the discharge operation to air pressure supply to the pneumatic device M1.

[0343] (7-4) Adjustment of power supply and demand The operation mode switching of the LAES device 7 and the adjustment of power supply and demand are performed in the same manner as in the first embodiment.

[0344] (7-5) Effects As with the CAES device of the first embodiment, it is possible to reduce the amount of electricity used in factory M, and to adjust the electricity demand of factory M by supplying air pressure while charging and discharging, thereby achieving supply and demand adjustment through storage of surplus electricity, regulated power generation, and demand response.

[0345] Furthermore, in the LAES apparatus of this embodiment, the tank capacity and installation space for air storage can be significantly reduced compared to the CAES apparatus, which means fewer installation restrictions and reduced equipment costs.

[0346] In the above-described embodiments 2 to 6, similarly to embodiment 1, the LAES device can be configured by storing compressed air as liquid air using the liquefaction unit 90 (see embodiments to example 12 described in Figs. 19 to 23).

[0347] (Variation) In each of the above embodiments, the renewable energy power generation device can be any device that utilizes energy that is constantly (or repeatedly) replenished by natural forces and that fluctuates irregularly, such as wind power, sunlight, solar heat, wave or tidal power, flowing water or tides, and geothermal heat.

[0348] Furthermore, the CAES apparatus 1 or LAES apparatus 7 of each embodiment can be applied even when the power demand of the factory M fluctuates greatly depending on the operating state of equipment that consumes a large amount of power in the factory M.

[0349] Furthermore, the power transmission and distribution system 5 is not limited to a general power transmission and distribution system of an electric power company, but may be a microgrid power system for a region or within a factory M.

[0350] Furthermore, in each embodiment, the number of pressure accumulator tanks 13 is two or three, but the number of pressure accumulator tanks 13 is not limited to this and can be any number.

[0351] Furthermore, it is also possible to provide a plurality of low-pressure accumulator tanks 13L and a plurality of high-pressure accumulator tanks 13H.

[0352] Furthermore, in the LAES device 7, the volume of the accumulator tank 13 may be significantly reduced. Because the pressure of the compressed air can be adjusted when vaporizing the liquid air, the accumulator tank can be configured with a volume just large enough to serve as a buffer to absorb pressure fluctuations.

[0353] In addition, the compressors 12a, 12b and the expanders 14a, 14b in each embodiment may be, for example, screw types, but the types of these rotary machines are not limited thereto. The compressors 12a, 12b and the expanders 14a, 14b may be, for example, scroll types, turbo types, centrifugal types, or reciprocating types.

[0354] In addition, in each embodiment, the compressor 12 and the expander 14 are configured as two-stage compression / two-stage expansion types, namely, compressors 12a and 12b and expanders 14a and 14b, respectively. However, the compressor 12 and the expander 14 may be single-stage compression / single-stage expansion types, or three or more stages of compression / expansion types, or may have different numbers of stages for compression and expansion.

[0355] Furthermore, in the LAES device 7, the second stage compressor can also be used as a booster compressor in the liquefaction unit 90.

[0356] Furthermore, although each drawing shows one compressor 12 and one expander 14, the number is not particularly limited, and the CAES apparatus 1 may be provided with a plurality of compressors 12 and expanders 14. Also, there may be configurations in which the number of motors and compressors differs (for example, when one motor drives multiple compressors), or the number of generators and expanders differs (for example, when multiple expanders drive one generator).

[0357] 5 illustrates a configuration in which compressed air is extracted from the pipe Le2 connecting the high-pressure stage expander 14a and the low-pressure stage expander 14b of the multi-stage expansion type expander 14, but it is also possible to employ a configuration in which compressed air is extracted from an intermediate stage of a single-stage expander. The same applies to the examples of FIGS. 13 and 17, and it is also possible to employ a configuration in which compressed air is extracted from an intermediate stage of a single-stage compressor.

[0358] In addition, in the seventh to twelfth embodiments, metal, quartz glass, and phase-change heat storage material are used as the low-temperature heat storage medium in the liquefaction unit 90. Metal and quartz glass have a large specific heat (heat capacity) and are suitable for low-temperature heat storage. In addition, concrete, gravel, etc. can also be used as the low-temperature heat storage medium.

[0359] Furthermore, although an organic material such as paraffin is used as the phase-change heat storage material, it is possible to select a material that changes phase at a temperature close to the phase-change temperature of air (solid-liquid phase), and other materials may also be used.

[0360] Furthermore, the method for liquefying compressed air is not limited to the above, and other methods may be used.

[0361] Furthermore, in embodiments 1 to 12, water (pressurized water) is used as the liquid high-temperature heat storage medium. Water has a larger specific heat (heat capacity) than other heat storage media such as silicone oil and synthetic oil, making it a suitable material for heat storage. It also has a high thermal conductivity and can efficiently transfer heat.

[0362] Furthermore, in the above-described embodiments 1 to 6, it is also possible to use a liquid heat storage medium other than water, such as oil, but oil-based heat storage media tend to have high viscosity at low temperatures and require large pump power for transportation, whereas water has low viscosity even at low temperatures and therefore has excellent transport properties, making it a preferred medium.

[0363] However, since water vaporizes at 100°C under normal pressure (atmospheric pressure), it is desirable to use pressurized water when storing high-temperature heat above 100°C. For example, when pressurized to 1 MPa, it is possible to maintain the liquid phase up to approximately 180°C. [Explanation of symbols]

[0364] 1...CAES device (compressed air energy storage device), 2...solar power generation device (renewable energy power generation device), 3...wind power generation device (renewable energy power generation device), 7...LAES device (liquid air energy storage device), 11...electric motor, 12...compressor, 12a...compressor (low pressure compressor), 12b...compressor (high pressure compressor), 13...accumulator tank, 13L...low pressure accumulator tank, 13H...high pressure accumulator tank, 14...expander, 14a...expander (high pressure expander) expansion machine), 14b...expander (low-pressure expander), 15...generator, 30...air pressure supply piping, 31-36...piping, 41...air pressure supply compressor, 42, 43...piping, 50...water supply pump, 70...control device, 80...pressure reducing device, 90...liquefaction unit, Lc1, Le2...piping, M...factory (facility using air pressure equipment), M1...air pressure equipment, P1...air pressure operating pressure, P2...specified pressure, P33-P34...pressure sensor, V31-V33...valve (on-off valve)

Claims

1. 1. A compressed air energy storage device connected to pneumatically driven pneumatic equipment, an electric motor driven by electric power from a power transmission and distribution system to which a renewable energy power generation device is connected; a compressor driven by the electric motor; an accumulator tank that stores the compressed air compressed by the compressor; an expander driven by the compressed air stored in the accumulator tank; a generator driven by the expander; a pipe through which the compressed air passes; a solenoid valve provided in the piping; a pressure sensor for detecting the pressure of the piping; a control device for controlling the solenoid valve, the piping includes an air pressure supply piping connected to the pneumatic device, The control device controls the solenoid valve to drive the expander with compressed air exceeding a predetermined pressure, and controls the solenoid valve to supply compressed air below the predetermined pressure from the air pressure supply pipe to the pneumatic equipment.

2. 2. The compressed air energy storage device of claim 1, The control device controls the compressor and the solenoid valve to drive either the compressor or the expander.

3. 3. The compressed air energy storage device according to claim 2, The control device is a compressed air energy storage device that, when the amount of power generated by the renewable energy power generation device is less than the amount of power consumption of the facility that uses the pneumatic equipment and a request to operate the pneumatic equipment is received, controls the solenoid valve to supply the compressed air from the pneumatic supply piping to the pneumatic equipment.

4. 3. The compressed air energy storage device according to claim 2, the air pressure supply piping includes piping that connects the accumulator tank and the air pressure device, The control device is a compressed air energy storage device that controls the solenoid valve to supply compressed air stored in the accumulator tank to the pneumatic equipment.

5. 3. The compressed air energy storage device according to claim 2, the expander includes a high-pressure expander driven by compressed air from the pressure accumulator tank and a low-pressure expander driven by compressed air discharged from the high-pressure expander, the air pressure supply piping includes piping that connects the high-pressure expander and the air pressure device, The control device controls the solenoid valve to drive the high-pressure expander with the compressed air, and supplies the compressed air discharged from the high-pressure expander to the pneumatic equipment.

6. 3. The compressed air energy storage device according to claim 2, The compressor includes a low-pressure compressor and a high-pressure compressor that compresses the compressed air compressed by the low-pressure compressor, the air pressure supply piping includes piping that connects the low-pressure compressor and the air pressure device, The control device is a compressed air energy storage device that drives the low-pressure compressor and controls the solenoid valve to supply compressed air compressed by the low-pressure compressor to the pneumatic equipment.

7. 3. The compressed air energy storage device according to claim 2, an air pressure supply compressor connected to the air pressure device via the air pressure supply piping; The control device is a compressed air energy storage device that, when the amount of power generated by the renewable energy power generation device is greater than the amount of power consumption of the facility that uses the pneumatic equipment and a request to operate the pneumatic equipment is received, drives the pneumatic supply compressor and controls the solenoid valve to supply compressed air compressed by the pneumatic supply compressor to the pneumatic equipment.

8. 3. The compressed air energy storage device according to claim 2, Further, a water supply pump connected to the pressure accumulator tank is provided. The control device is a compressed air energy storage device that drives the water supply pump to increase the tank pressure of the pressure accumulator tank.

9. 3. The compressed air energy storage device according to claim 2, The pressure accumulator tank includes a low-pressure accumulator tank that stores compressed air at a pressure equal to or lower than a predetermined pressure, and a high-pressure accumulator tank that stores compressed air that exceeds the predetermined pressure, The control device controls the solenoid valve to drive the expander using compressed air stored in the high-pressure accumulator tank, and controls the solenoid valve to supply compressed air stored in the low-pressure accumulator tank from the air pressure supply piping to the pneumatic equipment.

10. 10. The compressed air energy storage device of claim 9, The compressor includes a low-pressure compressor and a high-pressure compressor that compresses the compressed air compressed by the low-pressure compressor, the low-pressure accumulator tank stores compressed air compressed by the low-pressure compressor, The high-pressure accumulator tank is a compressed air energy storage device that stores the compressed air compressed by the high-pressure compressor.

11. 11. The compressed air energy storage device of claim 10, the low-pressure accumulator tank is connected to the high-pressure accumulator tank via a pressure reducing device; The control device controls the pressure reducing device to reduce the pressure of the compressed air stored in the high-pressure accumulator tank and supply the reduced pressure to the low-pressure accumulator tank.

12. 11. The compressed air energy storage device of claim 10, the air pressure supply piping includes piping that connects the low-pressure compressor and the air pressure device, The control device is a compressed air energy storage device that controls the solenoid valve to supply compressed air compressed by the low-pressure compressor to the pneumatic equipment.

13. 10. The compressed air energy storage device of claim 9, The compressor includes a low-pressure compressor and a high-pressure compressor that compresses the compressed air compressed by the low-pressure compressor, a heat exchanger that recovers heat from the compressed air compressed by the high-pressure compressor; a pipe connecting the low-pressure compressor and the heat exchanger, The control device controls the solenoid valve to provide the compressed air from the low-pressure compressor to the pneumatic equipment via a pipe connecting the low-pressure compressor and the heat exchanger.

14. 1. An energy storage device connected to a pneumatically driven pneumatic device, a compressor driven by electric power from a renewable energy power generation device; a heat exchanger that liquefies the compressed air compressed by the compressor and vaporizes the liquefied compressed air; an accumulator tank for storing the liquefied compressed air; an expander driven by the vaporized compressed air; a pipe through which the compressed air passes; a solenoid valve provided in the piping; a pressure sensor for detecting the pressure of the piping; a control device for controlling the solenoid valve, the piping includes an air pressure supply piping connected to the pneumatic device, The control device controls the solenoid valve based on the pressure detected by the pressure sensor, and supplies the compressed air to the expander or the pneumatic equipment.

15. 15. The energy storage device of claim 14, The control device controls the solenoid valve to drive the expander with compressed air exceeding a predetermined pressure, and controls the solenoid valve to supply compressed air below the predetermined pressure from the air pressure supply pipe to the pneumatic equipment.

16. 15. The energy storage device of claim 14, The control device is an energy storage device that controls the compressor and the solenoid valve to drive either the compressor or the expander.

17. 15. The energy storage device of claim 14, The control device is an energy storage device that controls the solenoid valve to supply the compressed air from the air pressure supply piping to the pneumatic equipment when the amount of power generated by the renewable energy power generation device is less than the amount of power consumption of the facility that uses the pneumatic equipment and a request to operate the pneumatic equipment is received.

18. 15. The energy storage device of claim 14, the air pressure supply piping includes piping that connects the accumulator tank and the air pressure device, The control device is an energy storage device that controls the solenoid valve to supply compressed air stored in the accumulator tank to the pneumatic equipment.

19. 15. The energy storage device of claim 14, the expander includes a high-pressure expander driven by compressed air from the pressure accumulator tank and a low-pressure expander driven by compressed air discharged from the high-pressure expander, the air pressure supply piping includes piping that connects the high-pressure expander and the air pressure device, The control device controls the solenoid valve to drive the high-pressure expander with the compressed air, and supplies the compressed air discharged from the high-pressure expander to the pneumatic equipment. An energy storage device.

20. 15. The energy storage device of claim 14, The compressor includes a low-pressure compressor and a high-pressure compressor that compresses the compressed air compressed by the low-pressure compressor, the air pressure supply piping includes piping that connects the low-pressure compressor and the air pressure device, The control device is an energy storage device that drives the low-pressure compressor and controls the solenoid valve to supply compressed air compressed by the low-pressure compressor to the pneumatic equipment.

21. 15. The energy storage device of claim 14, an air pressure supply compressor connected to the air pressure device via the air pressure supply piping; The control device is an energy storage device that, when the amount of power generated by the renewable energy power generation device is greater than the amount of power consumption of the facility that uses the pneumatic equipment and a request to operate the pneumatic equipment is received, drives the pneumatic supply compressor and controls the solenoid valve to supply compressed air compressed by the pneumatic supply compressor to the pneumatic equipment.

22. 15. The energy storage device of claim 14, the accumulator tank includes a compressed air accumulator tank that stores compressed air compressed by the compressor, a water supply pump connected to the compressed air accumulator tank; The control device is an energy storage device that drives the water supply pump and increases the tank pressure of the compressed air accumulator tank.

23. 15. The energy storage device of claim 14, the accumulator tank includes a compressed air accumulator tank that stores compressed air compressed by the compressor, The compressed air accumulator tank includes a low-pressure accumulator tank that stores compressed air at or below a predetermined pressure, and a high-pressure accumulator tank that stores compressed air above the predetermined pressure, The control device controls the solenoid valve to drive the expander using compressed air stored in the high-pressure accumulator tank, and controls the solenoid valve to supply compressed air stored in the low-pressure accumulator tank from the air pressure supply pipe to the pneumatic equipment.

24. 24. The energy storage device of claim 23, The compressor includes a low-pressure compressor and a high-pressure compressor that compresses the compressed air compressed by the low-pressure compressor, the low-pressure accumulator tank stores compressed air compressed by the low-pressure compressor, The high-pressure accumulator tank is an energy storage device that stores compressed air compressed by the high-pressure compressor.

25. 25. The energy storage device of claim 24, the low-pressure accumulator tank is connected to the high-pressure accumulator tank via a pressure reducing device; The control device is an energy storage device that controls the pressure reducing device to reduce the pressure of compressed air stored in the high-pressure accumulator tank and supply the reduced pressure to the low-pressure accumulator tank.

26. 25. The energy storage device of claim 24, the air pressure supply piping includes piping that connects the low-pressure compressor and the air pressure device, The control device is an energy storage device that controls the solenoid valve to supply compressed air compressed by the low-pressure compressor to the pneumatic equipment.

27. 24. The energy storage device of claim 23, The compressor includes a low-pressure compressor and a high-pressure compressor that compresses the compressed air compressed by the low-pressure compressor, a heat exchanger that recovers heat from the compressed air compressed by the high-pressure compressor; a pipe connecting the low-pressure compressor and the heat exchanger, The control device controls the solenoid valve to provide the compressed air from the low-pressure compressor to the pneumatic equipment via a pipe connecting the low-pressure compressor and the heat exchanger.

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