Compressed air energy storage device and heat pump device

Abstract

A compressed air energy storage device is provided with: a compressor that is driven by an electric motor and compresses air; a first heat exchanger that heats the heat storage medium by heat exchange with the compressed air compressed by the compressor; a pressure storage tank for storing the compressed air subjected to heat exchange by the first heat exchanger; an expansion machine driven by the compressed air stored in the pressure accumulation tank; a generator driven by the expander; a second heat exchanger that heats compressed air flowing into the expander by exchanging heat with the heat storage medium heated by the first heat exchanger; and a heat pump device for absorbing heat from the heat storage medium after heat exchange by the second heat exchanger and dissipating heat to compressed air that drives the expander.

Description

Technical Field

[0001] The invention relates to a compressed air energy storage device and a heat pump device. Background Art

[0002] Power generation using renewable energy sources such as wind power and solar power depends on meteorological conditions, so the amount of power generated fluctuates and is unstable. For such fluctuations, a system that levels the power generation is known as a compressed air energy storage (CAES) system. A compressed air energy storage device (CAES device) that uses the CAES system stores electrical energy in the form of compressed air in a pressure storage tank, and when electricity is needed, it uses compressed air to drive the expander to operate the generator, generate electrical energy, and level the output.

[0003] In a CAES device, in order to improve the power generation efficiency, there is a known system that recovers the compression heat to a heat storage medium and stores it in a heat storage tank, etc., and uses the recovered compression heat to heat the compressed air before expansion. As a result, the heat dissipation during storage in the accumulator tank is reduced, and the recovered power during expansion is increased. In a CAES device, the ratio of the output energy for driving the expander to generate electricity to the input energy when the compressed air is generated (power recovery efficiency) is required to be high. Therefore, heat recovery of the compression heat, that is, how much of the stored compression heat can be used to heat the compressed air that drives the expander, is important. Normally, the air temperature when compressing air at 20°C atmospheric pressure to about 1.0MPa is about 240°C. When heat recovery is performed by heat exchange through a heat storage medium, the effective energy is small and the amount of heat recovery is small.

[0004] As a CAES device that performs such heat recovery, there is, for example, a compressed air storage power generation device described in Patent Document 1. In the compressed air storage power generation device described in Patent Document 1, it is described that the compressed air before expansion is heated not only by a heat storage medium but also by external exhaust heat, thereby improving the power generation efficiency of the CAES device.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 6649141 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] However, the device described in Patent Document 1 improves the power generation efficiency of the CAES device by utilizing external exhaust heat. Therefore, the power generation efficiency cannot be improved without an appropriate external heat source, and the power recovery efficiency, which is the ratio of output power to input power, cannot be improved.

[0010] Technical solutions to solve problems

[0011] A compressed air energy storage device in one embodiment of the present invention comprises: a compressor driven by an electric motor to compress air; a first heat exchanger that heats a heat storage medium by heat exchange with the compressed air compressed by the compressor; a pressure storage tank that stores the compressed air that has undergone heat exchange in the first heat exchanger; an expander driven by the compressed air stored in the pressure storage tank; a generator driven by the expander; a second heat exchanger that heats the compressed air flowing into the expander by heat exchange with the heat storage medium heated in the first heat exchanger; and a heat pump device for absorbing heat from the heat storage medium that has undergone heat exchange in the second heat exchanger and dissipating heat to the compressed air that drives the expander.

[0012] Effects of the Invention

[0013] According to the present invention, by efficiently recovering the compression heat in the CAES device, it is possible to improve the power recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram showing a schematic structure of a compressed air energy storage device according to a first embodiment of the present invention.

[0015] Figure 2 It is a diagram showing a comparative example of the compressed air energy storage device with respect to the first embodiment.

[0016] Figure 3 It is a diagram showing a schematic structure of a compressed air energy storage device according to a second embodiment of the present invention.

[0017] Figure 4 It is a diagram showing a schematic structure of a compressed air energy storage device according to a third embodiment of the present invention.

[0018] Figure 5 It is a diagram showing a schematic structure of a compressed air energy storage device according to a fourth embodiment of the present invention.

[0019] Figure 6 It is a diagram showing a schematic structure of a compressed air energy storage device according to a fifth embodiment of the present invention.

[0020] Figure 7 It is a diagram showing a schematic structure of a compressed air energy storage device according to a sixth embodiment of the present invention.

[0021] Figure 8 It is a diagram showing a schematic structure of a compressed air energy storage device according to a seventh embodiment of the present invention.

[0022] Fig. 9 It is a diagram showing a schematic structure of a compressed air energy storage device according to an eighth embodiment of the present invention.

[0023] Fig.10 It is a diagram showing a schematic structure of a compressed air energy storage device according to a ninth embodiment of the present invention.

[0024] Fig.11 This is a diagram showing an example of a schematic structure of a compressed air energy storage device with a single-stage structure. DETAILED DESCRIPTION

[0025] Hereinafter, the mode for implementing the present invention will be described with reference to the accompanying drawings. The following description and the accompanying drawings are examples for illustrating the present invention, and are appropriately omitted and simplified for the purpose of clarifying the description. In addition, in the following description, the same or similar elements and processes are sometimes marked with the same figure numerals, and repeated descriptions are omitted. In addition, the content described below only represents an example of an embodiment of the present invention, and the present invention is not limited to the following embodiments, and can also be implemented in various other ways.

[0026] (First Embodiment)

[0027] Figure 1 1 is a diagram showing a schematic structure of a compressed air energy storage device (CAES device) according to a first embodiment of the present invention. The CAES device 1 is composed of a compressor unit 2A, an expander unit 2B, a heat storage unit 20, a heat pump unit 30, and a control device 40. The operations of the compressor unit 2A, the expander unit 2B, the heat storage unit 20, and the heat pump unit 30 are controlled by the control device 40.

[0028] The control device 40 is composed of a computer having processing devices such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a DSP (Digital Signal Processor), a non-volatile memory such as a ROM (Read Only Memory), a flash memory, a hard disk drive, a volatile memory called a so-called RAM (Random Access Memory), an input / output interface, and other peripheral circuits. These hardware cooperate to enable the software to operate and realize multiple functions. In addition, the controller can be composed of one computer or multiple computers. In addition, as a processing device, an ASIC (application specific integrated circuit), an FPGA (Field Programmable Gate Array), etc. can be used.

[0029] Programs capable of performing various operations are stored in the non-volatile memory. That is, the non-volatile memory is a storage medium (storage device) that can read the program that implements the functions of this embodiment. The volatile memory is a storage medium (storage device) that temporarily stores the operation results of the processing device and the signals input from the input interface. The processing device is a device that expands the program stored in the non-volatile memory in the volatile memory and performs operations, and performs prescribed operations on the data taken from the input / output interface, the non-volatile memory, and the volatile memory according to the program.

[0030] The compressor unit 2A has motors (electric motors) 4 and 5, compressors 6 and 7, a pressure storage tank 8 and an inverter device 9. The expander unit 2B has expanders 10 and 11, generators 12 and 13 and a power conditioner 14. In addition, the compressors 6 and 7 and the expanders 10 and 11 may also use compressors of any type such as screw type, scroll type, turbine type and reciprocating type. The heat storage unit 20 is a system in which a heat storage medium such as water circulates, and has heat storage tanks 21 and 22, heat exchangers 24 to 27 and delivery pumps 28 and 29. The heat pump unit 30 is a heat pump device that uses a vapor compression cycle using a refrigerant, and has a refrigerant compressor 31, an expansion valve 32, a radiator 34 and an evaporator 35.

[0031] The CAES device 1 is connected to a power grid 3 including a solar power generation device 18, a wind power generation device 19, etc. The inverter device 9 of the compressor unit 2A drives the motors 4, 5, etc. using the power supplied from the power grid 3. In addition, the power generated by the generators 12, 13 is supplied to the power grid 3 via the power conditioner 14.

[0032] The compressor 6 that undertakes the first stage compression stroke is driven to rotate by the motor 4. The compressor 7 that undertakes the second stage compression stroke is driven to rotate by the motor 5. The two-stage compression of air is performed by these compressors 6 and 7. The suction port of the compressor 6 is open to the atmosphere, and the discharge port of the compressor 6 is connected to the suction port of the second stage compressor 7 via the heat exchanger 24 of the heat storage unit 20. The discharge port of the compressor 7 is connected to the pressure storage tank 8 via the heat exchanger 25 of the heat storage unit 20.

[0033] On the other hand, in the expander unit 2B, the suction port of the expander 10 that undertakes the first stage expansion stroke is connected to the pressure storage tank 8 via the heat exchanger 26 of the heat storage unit 20. The discharge port of the expander 10 is connected to the suction port of the expander 11 that undertakes the second stage expansion stroke via the heat exchanger 27 of the heat storage unit 20. The two-stage expansion of the compressed air is performed by these expanders 10 and 11. The generator 12 is driven by the expander 10, and the generator 13 is driven by the expander 11, thereby generating electricity (power regeneration). The generators 12 and 13 are connected to the grid power 3 via the power conditioner 14, so that the regenerated power is returned to the grid power 3.

[0034] The heat storage unit 20 includes a heat storage medium passage for allowing the heat storage medium in the heat storage tank 22 to flow through the heat exchangers 24 and 25 connected in parallel and flow into the heat storage tank 21, and a heat storage medium passage for allowing the heat storage medium in the heat storage tank 21 to flow through the heat exchangers 26 and 27 connected in parallel and flow into the heat storage tank 22. The heat storage medium in the heat storage tanks 21 and 22 is transported by transport pumps 28 and 29. A radiator 34 of the heat pump unit 30 is provided in the heat storage medium passage between the heat storage tank 21 and the heat exchangers 26 and 27. In addition, an evaporator 35 of the heat pump unit 30 is provided in the heat storage medium passage between the heat exchangers 26 and 27 and the heat storage tank 22.

[0035] The heat pump unit 30 constitutes a refrigeration cycle, in which the refrigerant is compressed by the refrigerant compressor 31 and dissipates heat by the radiator 34. The refrigerant is decompressed by the expansion valve 32, absorbs heat in the evaporator 35, and returns to the refrigerant compressor 31. The refrigerant compressor 31 with a built-in motor is driven by input power from the grid power 3. As described above, the radiator 34 is provided in the heat storage medium passage between the heat storage tank 21 and the heat exchangers 26 and 27, and heat is dissipated from the refrigerant to the heat storage medium in the radiator 34. The evaporator 35 is provided in the heat storage medium passage returning from the heat exchangers 26 and 27 to the heat storage tank 22, and heat is absorbed from the heat storage medium to the refrigerant in the evaporator 35.

[0036] Next, the operation of the CAES device 1 will be described. As the thermal storage medium, water, pressurized water, mineral oils, glycols, or the like can be used, and the following description will take the case of using water as the thermal storage medium as an example.

[0037] (Charging action)

[0038] First, the charging operation of generating and storing compressed air will be described. During the charging operation, the control device 40 operates the motors 4, 5 and the delivery pump 29. When the delivery pump 29 is operated, the heat storage medium stored in the heat storage tank 22 on the low temperature side is supplied to the heat exchangers 24, 25. As described above, the compressor 6 is driven by the motor 4, and the compressor 7 is driven by the motor 5, so that the air sucked from the suction port of the compressor 6 is compressed in two stages and discharged from the discharge port of the compressor 7. The high-temperature compressed air adiabatically compressed by the compressor 6 flows into the heat exchanger 24 and exchanges heat with the heat storage medium supplied from the heat storage tank 22 on the low temperature side. Through this heat exchange, the low-temperature heat storage medium becomes a high temperature of about 100°C and is stored in the heat storage tank 21 on the high temperature side.

[0039] The compressed air that has undergone heat exchange in the heat exchanger 24 becomes low temperature, about normal temperature, and is sucked into the compressor 7 provided on the downstream side of the heat exchanger 24. The normal temperature compressed air sucked into the compressor 7 is subjected to the second stage of adiabatic compression by the compressor 7, and becomes high temperature and higher pressure compressed air. The compressed air discharged from the compressor 7 is introduced into the heat exchanger 25, and undergoes heat exchange with the heat storage medium supplied from the heat storage tank 22 on the low temperature side. Through this heat exchange, the low temperature heat storage medium becomes high temperature of about 100°C, and is stored in the heat storage tank 21 on the high temperature side. The compressed air that has undergone heat exchange in the heat exchanger 25 becomes low temperature, about normal temperature, and is stored in the pressure storage tank 8. Through the above actions, the compressed air energy is stored during charging.

[0040] (Discharge action)

[0041] Next, the discharge operation of generating electricity by driving the generator using compressed air will be described. During the discharge operation, the control device 40 operates the delivery pump 28 and the heat pump unit 30, and supplies the low-temperature and high-pressure compressed air stored in the pressure storage tank 8 to the heat exchanger 26. When the delivery pump 28 is operated, the heat storage medium stored in the heat storage tank 21 on the high temperature side is supplied to each heat exchanger 26, 27 via the radiator 34 of the heat pump unit 30. The temperature of the heat storage medium flowing from the heat storage tank 21 to the radiator 34 is about 70 to 90°C, although it also depends on the storage time in the heat storage tank 21. In addition, the temperature of the refrigerant flowing into the radiator 34 is, for example, about 120°C. When the heat storage medium passes through the radiator 34, the temperature of the heat storage medium becomes about 100°C through heat exchange with the refrigerant.

[0042] The compressed air flowing into the heat exchanger 26 becomes a high temperature of about 90°C by exchanging heat with the high-temperature heat storage medium. The compressed air heated to about 90°C in the heat exchanger 26 is supplied to the expander 10, and the first stage of adiabatic expansion is performed by driving the expander 10. The air adiabatically expanded by the expander 10 flows into the heat exchanger 27 provided between the discharge port of the expander 10 and the suction port of the expander 11. On the other hand, the heat storage medium at about 100°C flowing into the heat exchanger 26 becomes a low temperature of about 40°C by exchanging heat with the compressed air, and flows into the evaporator 35 of the heat pump unit 30.

[0043] The heat storage medium at about 100°C heated by the radiator 34 of the heat pump unit 30 is also supplied to the heat exchanger 27 provided on the inlet side of the expander 11. The air adiabatically expanded by the expander 10 flows into the heat exchanger 27 and exchanges heat with the high-temperature heat storage medium, thereby becoming a high temperature of about 90°C. The air heated to about 90°C in the heat exchanger 27 is sucked into the expander 11 and undergoes adiabatic expansion in the second stage. The air adiabatically expanded by the expander 11 becomes a low-temperature and low-pressure state and is discharged to the atmosphere from the discharge port of the expander 11. In this way, the low-temperature and high-pressure compressed air stored in the pressure storage tank 8 is heated by the heat storage medium stored in the heat storage tank 21, and the expanders 10 and 11 are driven by the heated compressed air, thereby generating electricity based on the generators 12 and 13. Then, the generated electricity is supplied to the grid power 3 via the power conditioner 14.

[0044] In addition, the heat storage medium at about 100°C flowing into the heat exchanger 27 becomes a low temperature of about 40°C by heat exchange, and flows out of the heat exchanger 27. The low-temperature heat storage medium flowing out of the heat exchanger 27 merges with the heat storage medium flowing out of the heat exchanger 26, and then flows into the evaporator 35 of the heat pump unit 30. In the evaporator 35, heat exchange is performed between the low-temperature (about 40°C) heat storage medium flowing in from the heat exchangers 26 and 27 and the refrigerant (about 20°C) whose temperature is reduced by the expansion valve 32. The heat storage medium whose temperature is reduced to about 20°C by heat exchange in the evaporator 35 flows into the heat storage tank 22 and is stored. On the other hand, the refrigerant absorbs heat from the heat storage medium in the evaporator 35 to evaporate, and returns to the refrigerant compressor 31.

[0045] Next, improvement of the power recovery efficiency in the present embodiment will be described. Figure 2 FIG. 1 is a diagram showing a comparative example with respect to the CAES device 1 of the present embodiment. Figure 2 The CAES device 100 shown in the comparative example of FIG. 1 is not provided with a heat pump unit 30, and the other structures are the same as those of FIG. Figure 1 The same situation.

[0046] In the CAES device 100, the heat storage medium stored in the heat storage tank 21 is Figure 1 As shown in the structure, the compressed air is not heated but supplied to the heat exchangers 26 and 27 as it is. As described above, even if the temperature of the heat storage medium flowing into the heat storage tank 21 is about 100°C, the temperature of the heat storage medium supplied from the heat storage tank 21 to the heat exchangers 26 and 27 is about 70 to 90°C due to heat dissipation during storage in the heat storage tank 21. Therefore, the temperature of the compressed air flowing out of the heat exchangers 26 and 27 after exchanging heat with the heat storage medium is about 70°C. Here, the compressed air supplied to the heat exchangers 26 and 27 during charging is about 100°C. Figure 2 The power input to the inverter device 9 is E1, and the regenerative power generated by the compressed air generated by the power E1 is E2. The power recovery efficiency in this case is E2 / E1, which is a value smaller than 1.

[0047] On the other hand, Figure 1 In the present embodiment shown, the heat pump unit 30 absorbs heat energy from the low temperature heat storage medium returning from the heat exchangers 26 and 27 to the heat storage tank 22, and releases heat energy to the high temperature heat storage medium supplied from the heat storage tank 21 to the heat exchangers 26 and 27. Therefore, the temperature of the heat storage medium supplied to the heat exchangers 26 and 27 is about 100°C. Therefore, the temperature of the compressed air flowing into the expanders 10 and 11 rises to about 90°C, and the regenerative power generated by the generators 12 and 13 is greater than Figure 2 the structural situation.

[0048] exist Figure 1 In the structure shown, in addition to the power E1 for generating compressed air, the power ΔE1 for driving the refrigerant compressor 31 of the heat pump unit 30 is required, so the power input to the inverter device 9 is "E1+ΔE1". Figure 1 In the case of Figure 2 Since the temperature is higher than about 70°C in the case of , the regenerative power generated by the generators 12 and 13 becomes a value "E2+ΔE2" larger than E2. Therefore, the power recovery efficiency in this case is expressed as (E2+ΔE2) / (E1+ΔE1).

[0049] In order to make the power recovery efficiency = (E2 + ΔE2) / (E1 + ΔE1) Figure 2 In the case of the power recovery rate = E2 / E1, in order to satisfy [(E2+ΔE2) / (E1+ΔE1)]>(E2 / E1), it is necessary to satisfy the condition "(ΔE2 / ΔE1)>(E2 / E1)...(1)". The COP (coefficient of performance) of the refrigeration cycle formed by the heat pump unit 30 is about 3.0, and energy about 3 times the electricity used to drive the refrigerant compressor 31 can be invested in the heat storage medium. Therefore, the effective energy of the heat storage medium increases, satisfying the above-mentioned conditional formula (1).

[0050] As described above, in the first embodiment, if Figure 1 As shown, a heat pump unit 30 is provided to absorb heat from the heat storage medium on the low temperature side and dissipate heat to the heat storage medium on the high temperature side, thereby being able to more efficiently recover the compression heat stored in the heat storage medium and to transfer heat to the compressed air before expansion. As a result, the compressed air supplied to the expanders 10 and 11 can be made to a higher temperature (about 90° C.), and the power recovery efficiency can be improved.

[0051] like Figure 2 As shown in the comparative example, when the CAES device 100 is not provided with a heat pump unit 30, the compressed air supplied to the expanders 10 and 11 is heated to about 70°C by heat exchange with a heat storage medium at 70 to 90°C. On the other hand, in the present embodiment, the compressed air is heated to about 90°C by heat exchange with a heat storage medium at about 100°C. In this case, the higher the temperature of the heat storage medium, the faster the temperature rise rate of the compressed air flowing out of the heat exchangers 26 and 27. Therefore, when the discharge operation starts, the supply of the heat storage medium is started to heat up the heat exchangers 26 and 27, and the temperature of the compressed air supplied to the expanders 10 and 11 becomes Figure 2 In other words, the power generation reaches the same level as Figure 2 When the power generation is the same value, the time ratio Figure 2 That is, it is possible to improve the responsiveness to changes in power demand.

[0052] (Second Embodiment)

[0053] Figure 3 1 is a diagram showing a schematic configuration of a compressed air energy storage device (CAES device) according to a second embodiment of the present invention. Hereinafter, the same components as those of the first embodiment are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0054] exist Figure 3 In the CAES device 1A of the second embodiment shown, the heat pump unit 30 has a refrigerant compressor 31, an expansion valve 32, two radiators 34a, 34b, and an evaporator 35. The radiator 34a is provided in the compressed air passage between the heat exchanger 26 and the expander 10. The radiator 34b is provided in the compressed air passage between the heat exchanger 27 and the expander 11. The evaporator 35 and Figure 1 The same is true for the case of the heat storage medium passage provided on the low temperature side between the heat exchangers 26 , 27 and the heat storage tank 22 .

[0055] The heat pump unit 30 constitutes a refrigeration cycle in which the refrigerant compressed by the refrigerant compressor 31 is split into two radiators 34a and 34b to dissipate heat respectively, then merges again to be decompressed by the expansion valve 32 and flows into the evaporator 35, where it absorbs heat and returns to the refrigerant compressor 31. In the second embodiment, the temperature of the refrigerant flowing into the radiators 34a and 34b is set to about 130°C. Other structures and Figure 1 The structure of the CAES device 1 is the same.

[0056] Next, the operation of the CAES device 1A will be described. As the heat storage medium, water, pressurized water, mineral oil, glycol, or other heat storage medium can be used. The following description will take the case where water is used as the heat storage medium as an example. Figure 1 The case of the CAES device 1 is the same as that of the CAES device 1, so the discharge operation is described below.

[0057] (Discharge action)

[0058] During the discharge operation, the control device 40 operates the delivery pump 28 and the heat pump unit 30, and supplies the low-temperature and high-pressure compressed air stored in the pressure storage tank 8 to the heat exchanger 26. When the delivery pump 28 is operated, the heat storage medium stored in the heat storage tank 21 on the high temperature side is supplied to each heat exchanger 26, 27. The temperature of the heat storage medium supplied from the heat storage tank 21 to each heat exchanger 26, 27 is about 70 to 90°C. The low-temperature and high-pressure compressed air supplied from the pressure storage tank 8 to the heat exchanger 26 exchanges heat with the heat storage medium in the heat exchanger 26, thereby increasing the temperature to about 70°C. On the other hand, the temperature of the heat storage medium after the heat exchange in the heat exchanger 26 is about 40°C, and flows into the evaporator 35 of the heat pump unit 30.

[0059] The compressed air that has passed through the heat exchanger 26 flows into the radiator 34a, exchanges heat with the high-temperature refrigerant, and the temperature further rises. As described above, the temperature of the refrigerant flowing into the radiator 34a is set to about 130°C, so the temperature of the compressed air that exchanges heat with the refrigerant and flows into the expander 10 rises to about 120°C. The temperature of the refrigerant flowing out of the radiator 34a decreases to about 80°C due to the heat exchange with the compressed air. The refrigerant of about 80°C flowing out of the radiator 34a returns to the expansion valve 32.

[0060] The compressed air at about 120°C flowing into the first-stage expander 10 undergoes a first-stage adiabatic expansion in the expander 10, thereby driving the expander 10. The compressed air whose pressure and temperature are reduced by the adiabatic expansion flows into the heat exchanger 27, and its temperature rises to about 70°C by heat exchange with the heat storage medium. On the other hand, the temperature of the heat storage medium after heat exchange in the heat exchanger 27 is about 40°C, and after merging with the heat storage medium from the heat exchanger 26, it flows into the evaporator 35 of the heat pump unit 30.

[0061] The compressed air that has passed through the heat exchanger 27 flows into the radiator 34b, and exchanges heat with the high-temperature heat storage medium, thereby further increasing the temperature. As described above, the temperature of the refrigerant flowing into the radiator 34b is set to about 130°C, so the temperature of the compressed air that exchanges heat with the refrigerant and flows into the expander 10 rises to about 120°C. The compressed air at about 120°C that flows into the second-stage expander 11 undergoes a second-stage adiabatic expansion in the expander 11, thereby driving the expander 11. The air that has been adiabatically expanded by the expander 11 becomes a low-temperature and low-pressure state, and is released to the atmosphere from the discharge port of the expander 11. In this way, the expanders 10 and 11 are driven by the compressed air heated by the radiators 34a and 34b, thereby generating electricity based on the generators 12 and 13, and supplying the power to the grid 3 through the power conditioner 14.

[0062] In the heat pump unit 30, the refrigerant flowing out of the radiator 34b is cooled to about 80°C by heat exchange with the compressed air, and returns to the expansion valve 32 after merging with the refrigerant flowing out of the radiator 34a. The refrigerant flowing out of the radiators 34a and 34b at about 80°C is expanded in the expansion valve 32, thereby cooling down to about 20°C, and flows into the evaporator 35. In the evaporator 35, the refrigerant at about 20°C is evaporated by heat exchange with the heat storage medium at about 40°C flowing in from the heat exchangers 26 and 27. The refrigerant that absorbs heat from the heat storage medium and evaporates is compressed by the refrigerant compressor 31 to a high temperature, and dissipates heat to the compressed air in the radiators 34a and 34b. As a result, the temperature of the compressed air is heated from about 70°C to about 120°C as described above.

[0063] In the first embodiment described above, the heat of the low temperature side heat storage medium is transferred to the high temperature side heat storage medium, and the high temperature side heat storage medium is used to heat the compressed air. When water is used as the heat storage medium, the temperature can only be raised to about 100°C, so the compressed air can only be heated to about 90°C.

[0064] On the other hand, in the second embodiment, the heat absorbed from the heat storage medium on the low temperature side is directly dissipated to the compressed air by the radiators 34a and 34b through which the refrigerant flows. Therefore, the compressed air flowing into the expanders 10 and 11 is heated by the radiators 34a and 34b to a temperature of about 120°C, which is higher than that in the first embodiment. That is, the heat energy recovered by the heat pump unit 30 is dissipated to the compressed air via the heat storage medium. Figure 1 Compared with the structure of the expansion machine 10, 11, the thermal efficiency is improved, the compressed air flowing into the expansion machine 10, 11 can be made to have a higher temperature, and the power recovery efficiency can be improved due to the increase in the generated power. In addition, in the second embodiment, the heating temperature of the compressed air based on the radiator 34a, 34b can be made higher, so the temperature of the compressed air before expansion is faster, which can further improve the responsiveness to the change of the power demand.

[0065] (Third Embodiment)

[0066] Figure 4 It is a diagram showing a schematic configuration of a compressed air energy storage device (CAES device) according to a third embodiment of the present invention. Figure 4 The CAES device 1B shown is a Figure 3 The heat exchangers 26 and 27 in the structure shown are replaced with the structure of three-fluid heat exchangers 26a and 27a. The refrigerant flowing out of the radiator 34a flows into the three-fluid heat exchanger 26a, and the refrigerant flowing out of the radiator 34b flows into the three-fluid heat exchanger 27a. Hereinafter, the same reference numerals are attached to the same components as those in the second embodiment, and repeated descriptions are omitted.

[0067] In the three-fluid heat exchangers 26a and 27a, the fluid passages on the heat dissipation side include a passage for the heat storage medium and a passage for the refrigerant, and the fluid passages on the heat absorption side include a passage for the compressed air. That is, in the three-fluid heat exchangers 26a and 27a, heat is transferred from the heat storage medium and the refrigerant to the compressed air, so that the compressed air is heated. Therefore, the three-fluid heat exchangers 26a and 27a are also elements of the heat storage unit 20, and can also be said to be elements of the heat pump unit 30. Other structures and Figure 3 In addition, as the heat storage medium, water, pressurized water, mineral oil, glycol or other heat storage medium can be used. The following description will be made by taking the case where water is used as the heat storage medium as an example.

[0068] The high-temperature refrigerant compressed by the refrigerant compressor 31 is divided and guided to the radiators 34a and 34b respectively. The refrigerant after heat exchange with the compressed air in the radiator 34a flows into the three-fluid heat exchanger 26a, and the refrigerant after heat exchange with the compressed air in the radiator 34b flows into the three-fluid heat exchanger 27a. The refrigerant that has passed through the three-fluid heat exchanger 26a and the refrigerant that has passed through the three-fluid heat exchanger 27a are merged and adiabatically expanded by the expansion valve 32, thereby reducing the temperature. The adiabatically expanded refrigerant absorbs heat from the heat storage medium on the low temperature side in the evaporator 35 and evaporates.

[0069] The temperature of the refrigerant compressed by the refrigerant compressor 31 is about 130°C. The refrigerant temperature is reduced to about 80°C by heat exchange with the compressed air in the radiator 34a. Furthermore, the refrigerant temperature is reduced to about 40°C by heat exchange with the compressed air in the three-fluid heat exchanger 26a. The temperature of the refrigerant passing through the radiator 34b and the three-fluid heat exchanger 27a is also about 80°C at the outlet of the radiator 34b and about 40°C at the outlet of the three-fluid heat exchanger 27a. In addition, the temperatures of the inlet and outlet of the three-fluid heat exchangers 26a and 27a of the heat storage medium are about 80°C (inlet) and about 40°C (outlet). The refrigerant of about 40°C flowing out of the three-fluid heat exchangers 26a and 27a is adiabatically expanded in the expansion valve 32 and the temperature is reduced.

[0070] In the second embodiment described above Figure 3 In the structure shown, the temperature of the refrigerant flowing into the expansion valve 32 is about 80°C, but Figure 4 In the structure shown, the temperature is lowered to about 40°C. Therefore, the temperature of the refrigerant after adiabatic expansion can be lowered, and the amount of heat absorbed from the heat storage medium to the refrigerant in the evaporator 35 (heat recovery) can be further increased. That is, the input power ΔE1 to the refrigerant compressor 31 when the compressed air is heated to about 120°C by the radiator 34a, 34b can be further reduced (refer to conditional expression (1)). As a result, the power recovery efficiency can be further improved. In addition, by further heating the compressed air by the radiator 34a, 34b, the temperature of the compressed air flowing into the expander 10, 11 can be further increased, so the temperature rise rate of the compressed air becomes faster, and the responsiveness to changes in power demand can be improved.

[0071] (Fourth Embodiment)

[0072] Figure 5 It is a diagram showing a schematic configuration of a compressed air energy storage device (CAES device) according to a fourth embodiment of the present invention. Figure 5 The CAES device 1C shown is Figure 1Compared with the CAES device 1 shown in FIG. 1 , the arrangement of the heat pump unit 30 is different. In addition, in the CAES device 1C, since the heat storage medium may become a high temperature of 100° C. or more, a mineral oil or glycol-based heat storage medium or pressurized water is used. Figure 1 The CAES device 1 shown is the same, and the same components are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0073] In the CAES device 1C, the evaporator 35 of the heat pump unit 30 is arranged in the heat storage medium passage on the low temperature side between the heat storage tank 22 and the heat exchangers 24 and 25, and the radiator 34 is arranged in the heat storage medium passage on the high temperature side between the heat exchangers 24 and 25 and the heat storage tank 21. The low temperature heat storage medium stored in the heat storage tank 22 passes through the evaporator 35 of the heat pump unit 30 and is supplied to the heat exchangers 24 and 25 connected in parallel. The heat storage medium flowing out of the heat exchangers 24 and 25 passes through the radiator 34 of the heat pump unit 30 and is stored in the heat storage tank 21.

[0074] Next, the charging operation and the discharging operation in the CAES device 1C will be described.

[0075] (Charging action)

[0076] During the charging operation, the control device 40 operates the motors 4 and 5, the heat pump unit 30, and the delivery pump 29. The operation of the motors 4 and 5 performs two-stage compression of the atmosphere by the compressors 6 and 7. In addition, the operation of the delivery pump 29 causes the heat storage medium at about 40°C stored in the heat storage tank 22 on the low temperature side to flow into the evaporator 35 of the heat pump unit 30. The heat storage medium flowing out of the heat storage tank 22 is absorbed by the refrigerant in the evaporator 35 of the heat pump unit 30, and the temperature of the heat storage medium is reduced from about 40°C to about 20°C. The heat storage medium at about 20°C flowing out of the evaporator 35 is divided and flows into each heat exchanger 24 and 25.

[0077] The high-temperature compressed air adiabatically compressed by the compressor 6 is discharged from the discharge port and flows into the heat exchanger 24, and exchanges heat with the heat storage medium of about 20°C supplied to the heat exchanger 24. Through this heat exchange, the temperature of the heat storage medium becomes about 100°C. The compressed air that has undergone heat exchange in the heat exchanger 24 becomes low temperature of about normal temperature, and is sucked into the compressor 7 disposed on the downstream side of the heat exchanger 24. The normal temperature compressed air sucked into the compressor 7 is subjected to a second stage of adiabatically compressed by the compressor 7, and becomes high-temperature and high-pressure compressed air. The compressed air discharged from the compressor 7 is introduced into the heat exchanger 25, and exchanges heat with the heat storage medium of about 20°C supplied to the heat exchanger 25. Through this heat exchange, the temperature of the heat storage medium becomes about 100°C. The compressed air that has undergone heat exchange in the heat exchanger 25 becomes low temperature of about normal temperature, and is stored in the pressure accumulator 8.

[0078] The heat storage medium flowing out of the heat exchangers 24 and 25 merges and flows into the radiator 34 of the heat pump unit 30. In the radiator 34, heat is dissipated from the refrigerant to the heat storage medium by heat exchange, and the temperature of the heat storage medium rises to about 120° C. The heat storage medium heated to about 120° C. is stored in the heat storage tank 21 on the high temperature side.

[0079] (Discharge action)

[0080] During the discharge operation, the control device 40 supplies the low-temperature and high-pressure compressed air stored in the pressure storage tank 8 to the heat exchanger 26, and drives the delivery pump 28 to supply the heat storage medium in the heat storage tank 21 on the high-temperature side to the heat exchangers 26 and 27. In addition, the temperature of the heat storage medium supplied to the heat exchangers 26 and 27 is slightly lower than 120° C. due to heat dissipation in the heat storage tank 21.

[0081] In the heat exchanger 26, the temperature of the compressed air rises to about 100°C and the temperature of the heat storage medium drops to about 40°C through heat exchange between the heat storage medium on the high temperature side and the compressed air. The compressed air heated to about 100°C in the heat exchanger 26 is sucked into the expander 10, and the expander 10 is driven by performing the first stage of adiabatic expansion. The air adiabatically expanded by the expander 10 is supplied to the heat exchanger 27, where it is heated to about 100°C by heat exchange with the heat storage medium. The air heated by the heat exchanger 27 is sucked into the expander 11 and performs the second stage of adiabatic expansion, driving the expander 11. The air adiabatically expanded by the expander 11 becomes a low temperature and low pressure state, and is discharged to the atmosphere from the discharge port of the expander 11. The expanders 10 and 11 are driven by compressed air, and power generation is performed by the generators 12 and 13. The generated power is supplied to the grid power 3 via the power conditioner 14.

[0082] In the first embodiment described above, water having a boiling point of 100° C. is used as the heat storage medium, and heat is transferred from the heat storage medium on the low temperature side flowing out of the heat exchangers 26 and 27 to the heat storage medium flowing into the heat exchangers 26 and 27 by the heat pump unit 30, thereby heating the temperature of the air supplied to the expanders 10 and 11 to about 90° C. On the other hand, in the fourth embodiment, a heat storage medium having a high boiling point such as pressurized water is used, and heat is transferred from the heat storage medium on the low temperature side to the heat storage medium on the high temperature side by the heat pump unit 30, thereby storing a heat storage medium at a higher temperature (about 120° C.) in the heat storage tank 21. By supplying the heat storage medium at a higher temperature (about 120° C.) stored in the heat storage tank 21 to the heat exchangers 26 and 27, the temperature of the compressed air supplied to the expanders 10 and 11 is heated to about 100° C.

[0083] Therefore, the temperature of the compressed air supplied to the expanders 10 and 11 can be made higher than that in the first embodiment, and the power recovery efficiency can be improved. In addition, the temperature of the heat storage medium flowing into the heat exchangers 26 and 27 can be made higher, so the time required for the temperature increase of the compressed air due to heat exchange can be shortened, and the responsiveness to the change in power demand can be improved.

[0084] (Fifth Embodiment)

[0085] Figure 6 It is a diagram showing a schematic configuration of a compressed air energy storage device (CAES device) according to a fifth embodiment of the present invention. Figure 6 The CAES device 1D shown is Figure 1 Compared with the CAES device 1 shown in FIG. 1 , the structure of the compressor unit 2A and the arrangement of the heat pump unit 30 are different. Figure 1 The structures shown are the same, the same reference numerals are given to the same structural elements, and repeated descriptions are omitted.

[0086] exist Figure 6 In the CAES device 1D shown, the compressor unit 2A has a plurality of accumulator tanks 8a, 8b, 8c, and also has opening and closing valves V1, V2, V3, and V4 for switching the flow path of the compressed air. The discharge port of the second-stage compressor 7 is connected to the heat exchanger 25 via the opening and closing valve V1, and is connected to the accumulator tank 8a storing high-temperature and high-pressure compressed air via the opening and closing valve V2. The outlet of the accumulator tank 8a is connected to the suction port of the expander 10 via the opening and closing valve V3 and the radiator 34 of the heat pump unit 30.

[0087] The outlet of compressed air in the heat exchanger 25 is connected to the accumulator tank 8b and the accumulator tank 8c storing low-temperature and high-pressure compressed air. The accumulator tank 8b and the accumulator tank 8c are connected by piping. The accumulator tank 8c is connected to the suction port of the expander 10 via the on-off valve V4 and the heat exchanger 26 of the expander unit 2B. In addition, since heat is easily dissipated in the accumulator tank 8a storing high-temperature and high-pressure heat storage medium, the volume of the accumulator tank 8a is set to be smaller than the total volume of the accumulator tanks 8b and 8c storing low-temperature and high-pressure compressed air.

[0088] The evaporator 35 of the heat pump unit 30 is provided in the heat storage medium passage on the low temperature side that returns from the heat exchangers 26 and 27 to the heat storage tank 22. On the other hand, the radiator 34 is provided in the passage of the high temperature and high pressure compressed air supplied from the pressure accumulator tank 8a to the expander 10. The heat pump unit 30 absorbs heat from the heat storage medium on the low temperature side through the evaporator 35, and dissipates the heat to the compressed air through the radiator 34. As a result, the high temperature and high pressure compressed air supplied from the pressure accumulator tank 8a to the expander 10 is heated by the radiator 34 and further becomes high temperature.

[0089] Next, the charging and discharging operations in the CAES device 1D will be described. As the thermal storage medium, water, pressurized water, mineral oils, glycols, and the like can be used, and the following description will take the case of using water as the thermal storage medium as an example.

[0090] (Charging action)

[0091] In the charging operation, the control device 40 first opens the on-off valves V1 and V2. In addition, when the CAES device 1D is in the stopped state, the on-off valves V1 to V4 are all closed. Then, the control device 40 drives the compressors 6 and 7 using the motors 4 and 5, and drives the delivery pump 29 to supply the heat storage medium stored in the heat storage tank 22 to the heat exchangers 24 and 25.

[0092] The high-temperature compressed air adiabatically compressed by the compressor 6 is discharged from the discharge port and flows into the heat exchanger 24, and performs heat exchange with the heat storage medium of about 20°C supplied to the heat exchanger 24. Through this heat exchange, the heat storage medium is heated to about 100°C and flows out of the heat exchanger 24. The compressed air that has undergone heat exchange in the heat exchanger 24 becomes low temperature of about normal temperature, and is sucked into the compressor 7 provided on the downstream side of the heat exchanger 24. The normal-temperature compressed air sucked into the compressor 7 is subjected to the second-stage adiabatic compression by the compressor 7, and becomes high-temperature and high-pressure compressed air.

[0093] The high-temperature and high-pressure compressed air discharged from the compressor 7 flows into the pressure storage tank 8a through the opening and closing valve V2, and flows into the heat exchanger 25 through the opening and closing valve V1. In addition, the temperature of the compressed air discharged by the second-stage adiabatic compression in the compressor 7 is about 130°C, so the temperature of the compressed air stored in the pressure storage tank 8a is about 120°C. In addition, the compressed air introduced into the heat exchanger 25 exchanges heat with the heat storage medium of about 20°C to become about room temperature, and is stored in the pressure storage tanks 8b and 8c. In addition, the temperature of the heat storage medium flowing out of the heat exchanger 25 becomes about 100°C by heat exchange with the compressed air. The heat storage medium flowing out of the heat exchanger 25 merges with the heat storage medium flowing out of the heat exchanger 24, flows into and is stored in the heat storage tank 21.

[0094] Next, when the pressure of the accumulator tank 8a reaches a predetermined pressure value, the on-off valve V2 is closed, and the storage of compressed air in the accumulator tank 8a is terminated. As a result, all the high-temperature and high-pressure compressed air discharged from the compressor 7 flows into the heat exchanger 25 through the on-off valve V1. In the heat exchanger 25, heat is transferred from the high-temperature compressed air to the heat storage medium, the heat storage medium is heated to about 100°C, and the compressed air becomes low temperature, which is about room temperature. The low-temperature and high-pressure compressed air flowing out of the heat exchanger 25 flows into the accumulator tank 8b and the accumulator tank 8c and is stored. On the other hand, the high-temperature (about 100°C) heat storage medium flowing out of the heat exchanger 25 merges with the high-temperature heat storage medium flowing out of the heat exchanger 24, flows into the heat storage tank 21 and is stored. When the pressure of the accumulator tanks 8b and 8c reaches a predetermined pressure value, the control device 40 closes the on-off valve V1, stops the delivery pump 28, and terminates the charging operation.

[0095] (Discharge action)

[0096] When the discharge operation starts, the control device 40 operates the delivery pump 28 and the heat pump unit 30, and opens the on-off valve V3. The high-temperature heat storage medium stored in the heat storage tank 21 is supplied to the heat exchangers 26 and 27 by the operation of the delivery pump 28. When the on-off valve V3 is in an open state, the compressed air of about 120°C stored in the pressure accumulator tank 8a is supplied to the expander 10 via the radiator 34 of the heat pump unit 30. The compressed air from the pressure accumulator tank 8a is heated to a high temperature of about 150°C by heat exchange with the high-temperature refrigerant in the radiator 34, and then supplied to the expander 10.

[0097] The compressed air at about 150°C supplied to the expander 10 is adiabatically expanded in the expander 10 and its temperature is reduced. The compressed air having a reduced temperature is heated to about 70°C by the heat exchanger 27 and then supplied to the second-stage expander 11. The air adiabatically expanded by the expander 11 becomes a low-temperature and low-pressure state and is released to the atmosphere from the discharge port of the expander 11. The expanders 10 and 11 are driven by the compressed air, and power generation is performed by the generators 12 and 13.

[0098] If the pressure of the accumulator tank 8a is lower than the pressure required for power generation, or if the predetermined preheating time has passed, the on-off valve V3 is closed and the on-off valve V4 is opened, thereby stopping the heat pump unit 30. As a result, the supply source of compressed air is switched from the accumulator tank 8a to the accumulator tanks 8b and 8c. The low-temperature and high-pressure compressed air in the accumulator tanks 8b and 8c flows into the heat exchanger 26 through the on-off valve V4. In addition, the volume of the accumulator tank 8a is set so that the time until the pressure is lower than the pressure required for power generation is sufficiently longer than the predetermined preheating time.

[0099] The compressed air flowing into the heat exchanger 26 is heated to about 70°C by heat exchange with the heat storage medium, and is adiabatically expanded by the expander 10 to drive the expander 10. The air that has become low temperature by adiabatically expanding by the expander 10 exchanges heat with the high-temperature heat storage medium in the heat exchanger 27, thereby becoming high temperature of about 70°C again and being supplied to the expander 11. The compressed air supplied to the expander 11 becomes low temperature and low pressure by performing the second stage adiabatically expansion in the expander 11, and is released to the atmosphere from the discharge port of the expander 11.

[0100] The above-mentioned preheating time is explained. In the heat exchangers 26 and 27, heat exchange is performed between the heat storage medium and the compressed air. At this time, after the supply of the heat storage medium just starts, the heat exchangers 26 and 27 are not sufficiently heated up, so when the compressed air supplied is low temperature and high pressure, the compressed air cannot be heated to a high temperature of about 70°C in the heat exchangers 26 and 27. Therefore, the expanders 10 and 11 cannot be rotated to a predetermined speed, and the power generation of the generators 12 and 13 cannot be fully performed. Here, the time from the start of supplying the heat storage medium to the heat exchangers 26 and 27 to the time when the heat exchangers 26 and 27 are sufficiently heated up to a state where the compressed air can be heated to about 70°C is referred to as the preheating time or preheating period.

[0101] In the present embodiment, the supply of the heat storage medium to the heat exchangers 26 and 27 is started at the same time as the charging operation is started, and then, after the preheating time or a time longer than the preheating time has passed, the supply source of the compressed air is switched to the accumulator tanks 8b and 8c. Therefore, when the supply source of the compressed air is switched to the accumulator tanks 8b and 8c, it is possible to prevent the generation of a decrease in the generated power due to insufficient preheating of the heat exchangers 26 and 27.

[0102] In addition, during the period from the start of the discharge operation including the preheating period to the time when the on-off valve V4 is switched to open, the high-temperature and high-pressure compressed air stored in the accumulator tank 8a is heated to about 150°C in the radiator 34 and then supplied to the expander 10. As a result, the expander 10 can quickly increase to the "rotation speed when supplying compressed air at about 150°C" together with the start of the discharge operation. That is, it is possible to achieve an improvement in responsiveness to changes in power demand. In addition, during the discharge operation based on the compressed air stored in the accumulator tank 8a, compressed air at about 150°C is supplied to the expander 10, which is different from the supply of compressed air at about 70°C to the expanders 10 and 11. Figure 2 Compared with the structure of , it is possible to improve the power recovery efficiency.

[0103] In the above-mentioned charging operation, the on-off valves V1 and V2 are opened at the same time as the charging starts, and the storage of high-temperature and high-pressure compressed air in the accumulator tank 8a and the storage of low-temperature and high-pressure compressed air in the accumulator tanks 8b and 8c are started at the same time. However, after the on-off valve V1 is closed and the on-off valve V2 is opened to store the high-temperature compressed air in the accumulator tank 8a, the on-off valve V1 and the on-off valve V2 may be opened to store the low-temperature compressed air in the accumulator tanks 8b and 8c.

[0104] For example, in the case of power leveling in wind power generation, multiple power generation is required in a day due to changes in wind direction, and the operating time of one power generation action is also short. Therefore, the impact of inefficient operation until the temperature of the rising edge becomes hot becomes greater. In such a case, during the charging action, the on-off valve V1 can be closed and the on-off valve V2 can be opened to store high-temperature compressed air in the pressure accumulator 8a. First, the pressure accumulator 8a is stored to a specified pressure value, so that in the subsequent repeated power generation actions, only the high-temperature and high-pressure compressed air stored in the pressure accumulator 8a is used to cope with power generation. In this way, it is effective to apply power smoothing to power grid power with large fluctuations in power demand and a large supply ratio of wind power generation with a relatively short cycle. On the other hand, in the case of solar power generation, the discharge action is about once a day, so any valve opening and closing mode can be used.

[0105] (Sixth Embodiment)

[0106] Figure 7 1 is a diagram showing a schematic structure of a compressed air energy storage device (CAES device) according to a sixth embodiment of the present invention. Figure 7 In the CAES device 1E shown, the pressure accumulators 8b and 8c are connected to the heat exchanger 26 via the on-off valve V4. The compressed air outflow side of the heat exchanger 26 is connected to the compressed air supply line between the on-off valve V3 and the radiator 34 via the on-off valve V5. Figure 6 The CAES device 1D shown is identical.

[0107] As mentioned above, in Figure 6 In the CAES device 1D shown in FIG. 1 , the high-temperature and high-pressure compressed air supplied from the accumulator tank 8a to the expander 10 is heated by the radiator 34, and the higher-temperature compressed air is supplied to the expander 10. Figure 7 In the CAES device 1E shown, not only the high-temperature and high-pressure compressed air supplied from the accumulator tank 8a to the expander 10, but also the low-temperature and high-pressure compressed air supplied from the accumulator tanks 8b and 8c to the expander 10 is heated by the radiator 34 and supplied to the expander 10. Regarding the operation of the CAES device 1E, the charging operation is similar to Figure 6The same is true for the CAES device 1D shown, and the discharge operation will be described below.

[0108] (Discharge action)

[0109] When the discharge operation starts, the control device 40 operates the delivery pump 28 and the heat pump unit 30, opens the on-off valve V3, and closes the on-off valves V4 and V5. The high-temperature heat storage medium stored in the heat storage tank 21 is supplied to the heat exchangers 26 and 27 by the operation of the delivery pump 28. When the on-off valve V3 is in the open state, the high-temperature and high-pressure compressed air stored in the pressure accumulator 8a is supplied to the expander 10 via the radiator 34 of the heat pump unit 30. The high-temperature and high-pressure compressed air from the pressure accumulator 8a is further heated by heat exchange with the high-temperature refrigerant in the radiator 34, and then supplied to the expander 10. As a result, power generation is performed based on the compressed air stored in the pressure accumulator 8a.

[0110] Next, if the pressure of the accumulator tank 8a is lower than the pressure required for power generation, or a predetermined preheating time has passed, the control device 40 closes the on-off valve V3 and opens the on-off valves V4 and V5. As a result, the supply source of compressed air is switched from the accumulator tank 8a to the accumulator tanks 8b and 8c. The low-temperature and high-pressure compressed air in the accumulator tanks 8b and 8c flows into the heat exchanger 26 through the on-off valve V4. The compressed air flowing into the heat exchanger 26 is heated by heat exchange with the heat storage medium, and then flows into the radiator 34 of the heat pump unit 30 through the on-off valve V5. The compressed air from the accumulator tanks 8b and 8c, which has been heated by the heat exchanger 26, is further heated by heat exchange with the high-temperature refrigerant in the radiator 34, and then supplied to the expander 10. As a result, power generation is performed using the compressed air stored in the accumulator tanks 8b and 8c.

[0111] As described above, in the CAES device 1E, not only the high-temperature and high-pressure compressed air supplied from the accumulator tank 8a to the expander 10 is heated by the radiator 34, but also the low-temperature and high-pressure compressed air supplied from the accumulator tanks 8b and 8c to the expander 10 is heated by the heat storage medium in the heat exchanger 26 and then further heated by the radiator 34. In this embodiment, when the supply source of compressed air is switched to the accumulator tanks 8b and 8c, it is possible to prevent the generation of power reduction due to insufficient preheating of the heat exchangers 26 and 27, as in the case of the CAES device 1D. In addition, the expander 10 can be started quickly at the start of the discharge operation, and the responsiveness to the change in power demand can be improved. Moreover, the power recovery efficiency can be improved not only during the discharge operation based on the compressed air of the accumulator tank 8a, but also during the discharge operation based on the low-temperature and high-pressure compressed air of the accumulator tanks 8b and 8c.

[0112] (Seventh Embodiment)

[0113] Figure 8 : is a diagram showing a schematic structure of a compressed air energy storage device (CAES device) according to a seventh embodiment of the present invention. Figure 8 In the CAES device 1F shown, the pressure accumulator 8a is connected to the expander 10 via the on-off valve V3. The pressure accumulators 8b and 8c are connected to the heat exchanger 26 via the on-off valve V4. The compressed air outflow side of the heat exchanger 26 is connected to the radiator 34. The compressed air outflow side of the radiator 34 is connected to the expander 10 via the on-off valve V6. Other structures are similar to Figure 6 The CAES device 1D shown is identical.

[0114] As mentioned above, in Figure 6 In the CAES device 1D shown in FIG. 1 , the high-temperature and high-pressure compressed air supplied from the accumulator tank 8a to the expander 10 is heated by the radiator 34, and the higher-temperature compressed air is supplied to the expander 10. Figure 8 In the CAES device 1F shown, only the low-temperature and high-pressure compressed air supplied from the accumulator tanks 8b and 8c to the expander 10 is heated by the radiator 34 and then supplied to the expander 10. Figure 6 The same is true for the CAES device 1D shown, and the discharge operation will be described below.

[0115] (Discharge action)

[0116] When the discharge operation starts, the control device 40 operates the delivery pump 28 and the heat pump unit 30, opens the on-off valve V3, and closes the on-off valves V4 and V6. The high-temperature heat storage medium stored in the heat storage tank 21 is supplied to the heat exchangers 26 and 27 by the operation of the delivery pump 28. When the on-off valve V3 is in the open state, the high-temperature and high-pressure compressed air stored in the pressure accumulator tank 8a is supplied to the expander 10. As a result, power generation is performed based on the compressed air stored in the pressure accumulator tank 8a.

[0117] Next, if the pressure of the accumulator tank 8a is lower than the pressure required for power generation, or a predetermined preheating time has passed, the control device 40 closes the on-off valve V3 and opens the on-off valves V4 and V6. As a result, the supply source of compressed air is switched from the accumulator tank 8a to the accumulator tanks 8b and 8c. The low-temperature and high-pressure compressed air in the accumulator tanks 8b and 8c flows into the heat exchanger 26 through the on-off valve V4. The compressed air flowing into the heat exchanger 26 is heated by heat exchange with the heat storage medium and then flows into the radiator 34 of the heat pump unit 30. The compressed air from the accumulator tanks 8b and 8c, which has been heated in the heat exchanger 26, is further heated by heat exchange with the high-temperature refrigerant in the radiator 34 and then supplied to the expander 10 through the on-off valve V6. As a result, power generation is performed based on the compressed air stored in the accumulator tanks 8b and 8c.

[0118] As described above, in the CAES device 1F, the low-temperature and high-pressure compressed air supplied from the accumulator tanks 8b and 8c to the expander 10 is heated by the heat storage medium in the heat exchanger 26, further heated by the radiator 34, and then supplied to the expander 10. Therefore, during the discharge operation using the low-temperature and high-pressure compressed air of the accumulator tanks 8b and 8c, the power recovery efficiency can be improved. In addition, when the supply source of compressed air is switched to the accumulator tanks 8b and 8c, the heat exchangers 26 and 27 have been preheated, so it is possible to prevent the reduction in generated power during the switching. Moreover, the high-temperature and high-pressure compressed air stored in the accumulator tank 8a at the start of discharge is supplied to the expander 10, so the expander 10 can be quickly started together with the start of the discharge operation, and the responsiveness to the change in power demand can be improved.

[0119] (Eighth Embodiment)

[0120] Fig. 9 : is a diagram showing a schematic structure of a compressed air energy storage device (CAES device) according to an eighth embodiment of the present invention. Fig. 9 In the CAES device 1G shown, the pressure accumulator tank 8a is connected to the expander 10 via the on-off valve V3. The pressure accumulator tanks 8b and 8c are connected to the radiator 34a via the on-off valve V4. The compressed air outflow side of the radiator 34a is connected to the heat exchanger 26. The compressed air outflow side of the heat exchanger 26 is connected to the expander 10 via the on-off valve V7. The discharge side of the expander 10 is connected to the heat exchanger 27 via the on-off valve V8, and is connected to the radiator 34b via the on-off valve V9. The compressed air outflow side of the radiator 34b is connected to the heat exchanger 27.

[0121] The refrigerant discharged from the refrigerant compressor 31 of the heat pump unit 30 is divided and flows into the radiators 34a and 34b. The refrigerant flowing out of the radiators 34a and 34b merges and flows into the expansion valve 32. The refrigerant adiabatically expanded by the expansion valve 32 is divided and flows into the evaporators 35a and 35b. The refrigerant flowing out of the evaporators 35a and 35b merges and returns to the refrigerant compressor 31.

[0122] The heat storage medium in the heat storage tank 21 on the high temperature side is supplied to the heat exchangers 26 and 27 by the delivery pump 28. The heat storage medium flowing out of the heat exchangers 26 and 27 flows into the evaporators 35a and 35b respectively after merging. The heat storage medium flowing out of the evaporators 35a and 35b returns to the heat storage tank 22 on the low temperature side after merging. Other structures and Figure 6 The CAES device 1G is similar to the CAES device 1D shown in FIG. Figure 6 The same is true for the CAES device 1D shown, and the discharge operation will be described below.

[0123] (Discharge action)

[0124] When the discharge operation starts, the control device 40 operates the delivery pump 28 and the heat pump unit 30, opens the on-off valves V3 and V8, and closes the on-off valves V4, V7, and V9. The high-temperature heat storage medium stored in the heat storage tank 21 is supplied to the heat exchangers 26 and 27 by the operation of the delivery pump 28, and the heat storage medium flowing out of the heat exchangers 26 and 27 returns to the heat storage tank 22 through the evaporators 35a and 35b. When the on-off valve V3 is in the open state, the high-temperature and high-pressure compressed air stored in the pressure accumulator tank 8a is supplied to the expander 10. The air adiabatically expanded in the expander 10 flows into the heat exchanger 27 through the on-off valve V8. The air heated by the heat storage medium in the heat exchanger 27 is subjected to the second-stage adiabatic expansion in the expander 11 and is discharged to the atmosphere. As a result, power generation is performed based on the compressed air stored in the pressure accumulator tank 8a.

[0125] Next, if the pressure of the accumulator tank 8a is lower than the pressure required for power generation, or if the predetermined preheating time has passed, the control device 40 closes the on-off valves V3 and V8 and opens the on-off valves V4, V7 and V9. As a result, the supply source of compressed air is switched from the accumulator tank 8a to the accumulator tanks 8b and 8c. The low-temperature and high-pressure compressed air of the accumulator tanks 8b and 8c flows into the radiator 34a through the on-off valve V4. The compressed air is heated by the radiator 34a and the temperature is increased, and then flows into the heat exchanger 26. The compressed air is heated by the heat storage medium in the heat exchanger 26 and the temperature is further increased, and then the compressed air is supplied to the expander 10 through the on-off valve V7. The compressed air adiabatically expanded in the expander 10 flows into the radiator 34b through the on-off valve V9. The compressed air heated by the refrigerant in the radiator 34b flows into the heat exchanger 27, and the temperature is further increased by the heat storage medium in the heat exchanger 27. The compressed air flowing out of the heat exchanger 27 is supplied to the expander 11 and undergoes adiabatic expansion in the second stage. In this way, power generation is performed using the compressed air stored in the accumulator tanks 8b and 8c.

[0126] In the CAES device 1G, the high-temperature and high-pressure compressed air stored in the accumulator tank 8a is supplied to the expander 10 at the start of discharge, so the expander 10 can be quickly started together with the start of the discharge operation, and the responsiveness to the change of power demand can be improved. In addition, when the supply source of compressed air is switched to the accumulator tanks 8b and 8c, the heat exchangers 26 and 27 have been preheated, so it is possible to prevent the reduction of the generated power during the switching. Moreover, when the discharge operation is performed using the low-temperature and high-pressure compressed air of the accumulator tanks 8b and 8c, the air heated by the radiator 34a is further heated by the heat exchanger 26 and supplied to the expander 10. Similarly, the air heated by the radiator 34b is further heated by the heat exchanger 27 and supplied to the expander 11, so that the power recovery efficiency can be improved.

[0127] (Ninth Embodiment)

[0128] Fig.10 It is a diagram showing a schematic structure of a compressed air energy storage device (CAES device) according to a ninth embodiment of the present invention. Fig.10 The CAES device 1H shown in the above Figure 5 In the structure using the heat pump unit 30 during the charging operation as in the CAES device 1C shown, a configuration is modified to include a plurality of pressure storage tanks 8a, 8b, 8c instead of the pressure storage tank 8. In addition, since the heat storage medium may become a high temperature of 100°C or more, a heat storage medium such as pressurized water, mineral oil, or ethylene glycol is used as the heat storage medium.

[0129] (Charging action)

[0130] In the charging operation, the control device 40 first opens the on-off valves V1 and V2. Then, the input power from the grid power 3 is used to drive the motors 4 and 5, the heat pump unit 30 and the delivery pump 29. Thus, two-stage compression of the atmosphere is performed based on the compressor 6 and the compressor 7. In addition, by driving the delivery pump 29, the heat storage medium at about 40°C stored in the heat storage tank 22 on the low temperature side is supplied to the heat exchangers 24 and 25 via the evaporator 35. The heat storage medium flowing out of the heat storage tank 22 absorbs heat from the refrigerant in the evaporator 35 of the heat pump unit 30, and the temperature drops from about 40°C to about 20°C. The heat storage medium at about 20°C flowing out of the evaporator 35 is divided and flows into each heat exchanger 24 and 25.

[0131] The high-temperature compressed air adiabatically compressed by the compressor 6 is discharged from the discharge port and flows into the heat exchanger 24, and performs heat exchange with the heat storage medium of about 20°C supplied to the heat exchanger 24. Through this heat exchange, the heat storage medium is heated to about 100°C and flows out of the heat exchanger 24. In addition, the compressed air that has undergone heat exchange in the heat exchanger 24 becomes low temperature of about normal temperature, and is sucked into the compressor 7 provided on the downstream side of the heat exchanger 24. The normal-temperature compressed air sucked into the compressor 7 is subjected to the second-stage adiabatic compression by the compressor 7, and becomes high-temperature and higher-pressure compressed air.

[0132] The high-temperature and high-pressure compressed air discharged from the compressor 7 is stored in the accumulator tank 8a via the on-off valve V2, and is stored in the accumulator tanks 8b and 8c after passing through the heat exchanger 25 via the on-off valve V1. In addition, the temperature of the compressed air discharged after the second-stage adiabatic compression in the compressor 7 is about 130°C, so the temperature of the compressed air stored in the accumulator tank 8a is about 120°C. The compressed air introduced into the heat exchanger 25 exchanges heat with the heat storage medium at about 20°C and becomes about room temperature, and is stored in the accumulator tanks 8b and 8c. In addition, the temperature of the heat storage medium flowing out of the heat exchanger 25 becomes about 100°C by heat exchange with the compressed air.

[0133] The heat storage medium flowing out of the heat exchangers 24 and 25 merges and flows into the radiator 34 of the heat pump unit 30. In the radiator 34, heat is dissipated from the refrigerant to the heat storage medium by heat exchange, and the temperature of the heat storage medium rises to about 120° C. The heat storage medium heated to about 120° C. is stored in the heat storage tank 21 on the high temperature side.

[0134] Next, when the pressure of the accumulator tank 8a reaches a predetermined pressure value, the on-off valve V2 is closed, and the storage of compressed air in the accumulator tank 8a is terminated. As a result, all the high-temperature and high-pressure compressed air discharged from the compressor 7 flows into the heat exchanger 25 through the on-off valve V1. In the heat exchanger 25, heat is transferred from the high-temperature compressed air to the heat storage medium, the heat storage medium is heated to about 100°C, and the compressed air becomes low temperature, which is about room temperature. The low-temperature and high-pressure compressed air flowing out of the heat exchanger 25 flows into the accumulator tanks 8b and 8c and is stored.

[0135] (Discharge action)

[0136] When the discharge operation starts, the control device 40 operates the delivery pump 28 and opens the on-off valve V3. The high-temperature heat storage medium stored in the heat storage tank 21 is supplied to the heat exchangers 26 and 27 by the operation of the delivery pump 28. When the on-off valve V3 is in the open state, the compressed air of about 120°C stored in the pressure storage tank 8a is supplied to the expander 10 via the radiator 34 of the heat pump unit 30. The compressed air of about 120°C supplied to the expander 10 is adiabatically expanded in the expander 10 and its temperature is reduced. The compressed air with a reduced temperature is heated to about 100°C by the heat exchanger 27 and then supplied to the second-stage expander 11. The air adiabatically expanded by the expander 11 becomes a low-temperature and low-pressure state and is opened to the atmosphere from the discharge port of the expander 11. The expanders 10 and 11 are driven by the compressed air, and power generation is performed by the generators 12 and 13.

[0137] If the pressure of the accumulator tank 8a is lower than the pressure required for power generation, or if the prescribed preheating time has passed, the on-off valve V3 is closed and the on-off valve V4 is opened to switch the supply source of compressed air from the accumulator tank 8a to the accumulator tanks 8b and 8c. The low-temperature, constant-pressure compressed air from the accumulator tanks 8b and 8c flows into the heat exchanger 26 through the on-off valve V4. The compressed air flowing into the heat exchanger 26 is heated to about 70°C by heat exchange with the heat storage medium, and is adiabatically expanded in the expander 10 to drive the expander 10. The air that has become low temperature by adiabatically expanding the expander 10 exchanges heat with the high-temperature heat storage medium in the heat exchanger 27, thereby becoming a high temperature of about 70°C again and being supplied to the expander 11. The compressed air supplied to the expander 11 becomes low-temperature and low-pressure by performing the second-stage adiabatic expansion in the expander 11, and is released to the atmosphere from the discharge port of the expander 11.

[0138] In this embodiment, Figure 6 In the same manner as in the case of the CAES device 1D, the supply of the heat storage medium to the heat exchangers 26 and 27 starts at the same time as the charging operation starts, and then, after the preheating time or a longer time has passed, the on-off valve V4 is opened to switch the supply source of the compressed air to the pressure accumulator tanks 8b and 8c. Therefore, when the supply source of the compressed air is switched to the pressure accumulator tanks 8b and 8c, the reduction in the generated power due to insufficient preheating of the heat exchangers 26 and 27 can be prevented.

[0139] In addition, in this embodiment, Figure 5In the case of the CAES device 1C of the embodiment, a heat storage medium with a high boiling point such as pressurized water is used, and heat is transferred from the heat storage medium on the low temperature side to the heat storage medium on the high temperature side by the heat pump unit 30, so that a heat storage medium with a higher temperature (about 120°C) is stored in the heat storage tank 21. By supplying the heat storage medium with a higher temperature (about 120°C) stored in the heat storage tank 21 to the heat exchangers 26 and 27, the temperature of the air supplied to the expanders 10 and 11 is heated to about 100°C higher than that in the case of the first embodiment. As a result, it is possible to achieve an improvement in the power recovery efficiency.

[0140] In addition, during the period from the start of the discharge operation including the preheating period to the time when the on-off valve V4 is switched to open, the high-temperature and high-pressure compressed air stored in the accumulator tank 8a is supplied to the expander 10. As a result, the expander 10 can be quickly started at the start of the discharge operation, and the responsiveness to the change in power demand can be improved.

[0141] In each of the above-mentioned embodiments, it is constructed as a two-stage compression / two-stage expansion type based on compressors 6, 7 and expanders 10, 11, but single-stage compression / single-stage expansion, or three or more stages, and further, a combination of different numbers of compression and expansion stages can also be applied. Moreover, the number of compressors and expanders is 1, but the number is not particularly limited, and it can also be more than 2. In addition, the number of motors and compressors, generators and expanders can also be a combination of different numbers. Moreover, in each embodiment, the compressors 6, 7 and expanders 10, 11 are used as separate devices, but the compressors and expanders (motor and generator) can also be used together.

[0142] For example, Fig.11 The CAES device 1J shown in FIG. Figure 1 The case where the two-stage CAES device 1 shown is changed to a single-stage structure. During the charging operation, the compressed air compressed by the compressor 6 in a single stage exchanges heat with the heat storage medium in the heat exchanger 24, and is stored in the pressure storage tank 8 as low-temperature and high-pressure compressed air. The heat storage medium heated in the heat exchanger 24 is stored in the heat storage tank 21. During the discharging operation, the heat storage medium flowing out of the heat storage tank 21 is heated by the radiator 34 of the heat pump unit 30 and then supplied to the heat exchanger 26. The compressed air supplied from the pressure storage tank 8 to the expander 10 is heated by the heat exchange with the heat storage medium in the heat exchanger 26, and then supplied to the expander 10.

[0143] The CAES device 1J is also provided with a heat pump unit 30, which absorbs heat from the low-temperature heat storage medium discharged from the heat exchanger 26 and dissipates heat to the high-temperature heat storage medium flowing into the heat exchanger 26. Therefore, the compression heat accumulated in the heat storage medium can be recovered more efficiently and heat can be transferred to the compressed air before expansion, so that the compressed air supplied to the expander 10 can be made hotter. As a result, the power recovery efficiency can be improved, and the responsiveness to the change in power demand can be further improved.

[0144] also, Fig.11 The single-stage structure of the charging side (motor 4, compressor 6, heat exchanger 24) and the single-stage structure of the power generation side (heat exchanger 26, expander 10, generator 12) shown can also be applied to Figures 1 to 10 Each CAES device.

[0145] According to each of the above-described embodiments, the following effects are achieved.

[0146] (C1) Fig.11 As shown, a compressed air energy storage device (CAES device) 1J comprises: a compressor 6 driven by a motor (motor) 4 to compress air; a first heat exchanger 24 for heating a heat storage medium by heat exchange with the compressed air compressed by the compressor 6; a pressure storage tank 8 for storing compressed air after heat exchange in the heat exchanger 24; an expander 10 driven by the compressed air stored in the pressure storage tank 8; a generator 12 driven by the expander 10; a heat exchanger (second heat exchanger) 26 for heating the compressed air flowing into the expander 10 by heat exchange with the heat storage medium heated in the heat exchanger (first heat exchanger) 24; and a heat pump unit (heat pump device) 30 for absorbing heat from the heat storage medium after heat exchange in the heat exchanger 26 and dissipating heat to the compressed air driving the expander 10.

[0147] (C2) In the above (C1), if Figure 1 , Fig.11 As shown in FIG. 1 and FIG. 2 , the heat pump unit 30 may absorb heat from the heat storage medium after heat exchange in the heat exchangers 26 and 27 and dissipate heat to the heat storage medium supplied to the heat exchangers 26 and 27 .

[0148] Regarding the above (C1) and (C2), for example, Fig.11In the CAES device 1J shown, a heat pump unit 30 is used to absorb heat from the heat storage medium on the low temperature side discharged from the heat exchanger 26 that heats the compressed air, and dissipate heat to the heat storage medium on the high temperature side that is heated in the heat exchanger 24 and flows into the heat exchanger 26. That is, the heat energy absorbed from the heat storage medium on the low temperature side is dissipated to the compressed air driving the expander 10 via the heat storage medium flowing into the heat exchanger 26. Therefore, the compression heat (heat energy) accumulated in the heat storage medium can be recovered more efficiently and heat can be transferred to the compressed air before expansion. As a result, the heat storage medium flowing into the heat exchanger 26 becomes higher in temperature, and the compressed air supplied to the expander 10 can be made higher in temperature. That is, the power recovery efficiency can be improved, and the responsiveness to changes in power demand can be further improved.

[0149] (C3) In the above (C1), if Figure 3 As shown in the CAES device 1A, the heat pump unit 30 has an evaporator (heat absorber) 35 and radiators 34a, 34b through which the refrigerant circulates. The evaporator 35 absorbs heat from the heat storage medium after heat exchange in the heat exchanger 26, and the radiators 34a, 34b dissipate the heat energy absorbed in the evaporator 35 to the compressed air heated by the heat exchangers 26, 27.

[0150] The compressed air heated by the heat exchanger 26 is further heated by the radiator 34a and supplied to the expander 10, and the compressed air heated by the heat exchanger 27 is further heated by the radiator 34b and supplied to the expander 11. Figure 3 In the CAES device 1A shown, the heat energy absorbed from the heat storage medium on the low temperature side by the evaporator 35 is dissipated to the compressed air heated by the heat exchangers 26 and 27 through the radiators 34a and 34b. As a result, the compressed air driving the expanders 10 and 11 can be heated to a higher temperature, and the power recovery efficiency can be improved by increasing the generated power. In addition, since the temperature of the compressed air can be heated to a higher temperature, the temperature of the compressed air before expansion is increased quickly, and the responsiveness to the change in power demand can be further improved.

[0151] (C4) In (C3) above, if Figure 4 As shown in the CAES device 1B, the heat exchanger (26a, 27a) is composed of three-fluid heat exchangers 26a, 27a, into which flow the heat storage medium heated in the heat exchangers 24, 25, the refrigerant flowing out of the radiators 34a, 34b, and the compressed air supplied to the expanders 10, 11. Since the heat storage medium that has dissipated heat to the compressed air through the radiators 34a, 34b flows into the three-fluid heat exchangers 26a, 27a and dissipates heat to the compressed air, the temperature of the refrigerant returning to the expansion valve 32 of the heat pump unit 30 is equal to Figure 3Therefore, the temperature of the refrigerant after adiabatic expansion can be lowered, and the heat absorption (heat recovery) from the heat storage medium to the refrigerant in the evaporator 35 can be further increased. As a result, the heat recovery efficiency based on the heat pump unit 30 becomes higher, the power consumption can be reduced, and the power recovery efficiency of the CAES device 1B can be improved.

[0152] (C5) In the above (C1), if Figure 6 As shown, unlike the accumulator tanks (main accumulator tanks) 8b and 8c storing compressed air after heat exchange in the heat exchangers (first heat exchangers) 24 and 25, the CAES device 1D further has an accumulator tank (auxiliary accumulator tank) 8a, which is connected to the compressed air inlet side of the heat exchanger 25 and is used to store the compressed air compressed by the compressors 6 and 7. The heat exchangers (second heat exchangers) 26 and 27 heat the compressed air flowing from the accumulator tanks 8b and 8c to the expanders 10 and 11 by heat exchange with the heat storage medium heated in the heat exchangers 24 and 25, and has a control device 40, which drives the expanders 10 and 11 using the compressed air stored in the accumulator tanks 8a, starts the flow of the heat storage medium heated by the heat exchangers 24 and 25 into the heat exchangers 26 and 27, and then drives the expanders 10 and 11 using the compressed air stored in the accumulator tanks 8b and 8c.

[0153] For example, in Figure 6 to Figure 9 In the CAES devices 1D to 1G shown in FIG. 1 , the heat pump unit 30 absorbs heat from the heat storage medium after heat exchange in the heat exchangers 26 and 27 and dissipates the heat to the compressed air supplied to the expanders 10 and 11 through the radiator 34. Fig.10 In the CAES devices 1D to 1G shown, the heat pump unit 30 absorbs heat from the heat storage medium after heat exchange in the heat exchangers 26 and 27, and dissipates the heat to the heat storage medium supplied to the heat exchangers 26 and 27 through the radiator 34. That is, the heat absorbed from the heat storage medium on the low temperature side is dissipated to the compressed air driving the expanders 10 and 11 via the heat storage medium flowing into the heat exchangers 26 and 27.

[0154] As described above, the heat pump unit 30 absorbs heat from the heat storage medium after heat exchange in the heat exchangers 26 and 27, and dissipates the heat to the compressed air driving the expanders 10 and 11. Therefore, the temperature of the compressed air supplied to the expanders 10 and 11 can be made higher than that of the prior art, and the power recovery efficiency and responsiveness can be further improved.

[0155] In addition, after the expansion machines 10 and 11 are driven by the high-temperature and high-pressure compressed air stored in the pressure accumulator tank 8a, the drive is switched to the low-temperature and high-pressure compressed air based on the pressure accumulator tanks 8b and 8c. Therefore, the expansion machines 10 and 11 can be started quickly together with the start of the discharge action, and the responsiveness to changes in power demand can be improved.

[0156] Furthermore, the expansion machines 10 and 11 are driven by the compressed air stored in the pressure accumulator tank 8a, and the heat storage medium heated in the heat exchanger 24 starts to flow into the heat exchangers 26 and 27. Thereafter, the expansion machines 10 and 11 are driven by the compressed air stored in the pressure accumulator tanks 8b and 8c. This prevents a decrease in the generated power due to insufficient preheating of the heat exchangers 26 and 27 when the supply source of the compressed air is switched from the pressure accumulator tank 8a to the pressure accumulator tanks 8b and 8c.

[0157] (C6) In the above (C5), the heat pump unit 30 absorbs heat from the heat storage medium after heat exchange in the heat exchangers 26 and 27, and dissipates heat to at least one of the compressed air flowing from the accumulator tanks 8b and 8c into the expander 10 and the compressed air flowing from the accumulator tank 8a into the expander 10. For example, Figure 6 In the CAES device 1D shown in the figure, heat is dissipated to the compressed air flowing from the accumulator tank 8a into the expander 10. Figure 7 In the CAES device 1E shown in the figure, heat is dissipated to both the compressed air flowing into the expander 10 from the accumulator tank 8a and the accumulator tanks 8b and 8c. Figure 8 , Fig. 9 In the CAES devices 1F and 1G shown, heat is dissipated to the compressed air flowing from the accumulator tanks 8b and 8c into the expander 10. Therefore, the temperature of the compressed air supplied to the expanders 10 and 11 can be made higher than in the prior art, and the power recovery efficiency and responsiveness can be further improved.

[0158] (C7) In the above (C6), if Fig. 9 As shown in the CAES device 1G, the expanders 10 and 11 constitute a multi-stage expander, and have the expander 10 as the first expansion stage and the expander 11 as the second expansion stage. The heat exchangers 26 and 27 are respectively provided on the inflow sides of the expanders 10 and 11, and the heat pump unit 30 absorbs heat from the heat storage medium after heat exchange in the heat exchangers 26 and 27, and dissipates heat to the compressed air flowing from the pressure accumulator tanks 8b and 8c to the expander 10 and the compressed air flowing from the expander 10 to the expander 11. Therefore, the power generation amount based on the generator 12 driven by the expander 10 and the power generation amount based on the generator 13 driven by the expander 11 are increased, and the power recovery efficiency can be improved.

[0159] (C8) In (C5) above, if Fig.10As shown in the CAES device 1H shown in the figure, the heat pump unit 30 absorbs heat from the heat storage medium after the heat exchange in the heat exchangers 26 and 27, and dissipates heat to the heat storage medium supplied to the heat exchangers 26 and 27. Therefore, the heat energy absorbed by the heat storage medium after the heat exchange in the heat exchangers 26 and 27 is dissipated to the compressed air supplied to the expanders 10 and 11 via the heat storage medium supplied to the heat exchangers 26 and 27. As a result, the temperature of the compressed air supplied to the expanders 10 and 11 can be made higher than that of the conventional technology, and the power recovery efficiency can be improved and the responsiveness can be further improved.

[0160] (C9) In the above (C1), the heat pump unit 30 may use a heat pump device that uses a vapor compression cycle that utilizes a refrigerant.

[0161] (C10) In the above (C1), pressurized water is used as the heat storage medium. The boiling point of pressurized water is higher than that of unpressurized water, so the temperature of the heat storage medium can be raised to a higher level, and the compressed air can be heated to a higher temperature by the heat storage medium, which can further improve the power recovery efficiency.

[0162] (C11) Fig.11 As shown, the heat pump unit 30 is a heat pump device used in a compressed air energy storage device, which stores compressed air and compression heat obtained by the compressor 6 compressing the air, heats the compressed air by heat exchange between the compressed air at the heat exchanger 26 and the heat storage medium that absorbs the compression heat, and uses the heated compressed air to drive the expander 10 to generate electricity. The heat pump device has: an evaporator 35 that absorbs heat from the heat storage medium that has undergone heat exchange at the heat exchanger 26; and a radiator 34 that dissipates heat from the heat storage medium that flows into the heat exchanger 26. Therefore, by using the heat pump unit 30, the heat energy stored in the heat storage medium can be efficiently transported to the compressed air, and the power recovery efficiency in the compressed air energy storage device can be improved.

[0163] In each of the above-described embodiments, as the object of power generation based on renewable energy, for example, all methods of energy that is stably or repeatedly supplemented by natural forces and irregularly changes, such as wind power, sunlight, solar heat, wave power or tidal power, flowing water or tides, and geothermal heat, can be used as the object. In addition, it can also be an object whose power changes due to other equipment in the factory that consumes a lot of power. In addition, the grid power that supplies these powers can not only be grid power, but also microgrid power in a region or factory.

[0164] The embodiments of the present invention are described above, but the above embodiments are only a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific structures of the above embodiments. For example, in the above embodiments, the heat pump unit 30 uses a heat pump device that uses a vapor compression cycle using a refrigerant, but an absorption heat pump device may also be used. In addition, the structures described in the above different embodiments may be combined with each other.

[0165] Description of Reference Numerals

[0166] 1, 1A~1H, 1J... compressed air energy storage device (CAES device), 2A... compressor unit, 2B... expander unit, 3... grid power, 4, 5... motor (electric motor), 6, 7... compressor, 8, 8a, 8b, 8c... pressure storage tank, 9... inverter device, 10, 11... expander, 12, 13... generator, 14... power conditioner, 20... heat storage unit, 21, 22... heat storage tank, 24~27... heat exchanger, 26a, 27a... three-fluid heat exchanger, 28, 29... transfer pump, 30... heat pump unit, 31... refrigerant compressor, 32... expansion valve, 34, 34a, 34b... radiator, 35... evaporator, 40... control device.

Claims

1. A compressed air energy storage device, characterized in that: have: A compressor driven by an electric motor to compress air; a first heat exchanger for heating the heat storage medium by exchanging heat with compressed air compressed by the compressor; an accumulator tank for storing compressed air after heat exchange by the first heat exchanger; an expander driven by compressed air stored in the accumulator tank; a generator driven by the expander; a second heat exchanger for heating the compressed air flowing into the expander by exchanging heat with the heat storage medium heated by the first heat exchanger; and A heat pump device for absorbing heat from the heat storage medium after heat exchange in the second heat exchanger and dissipating the heat to compressed air driving the expander.

2. The compressed air energy storage device according to claim 1, characterized in that: The heat pump device absorbs heat from the heat storage medium that has undergone heat exchange in the second heat exchanger, and dissipates heat to the heat storage medium supplied to the second heat exchanger.

3. The compressed air energy storage device according to claim 1, characterized in that: The heat pump device has a heat absorber and a heat sink for flowing refrigerant. The heat absorber absorbs heat from the heat storage medium after heat exchange by the second heat exchanger. The radiator dissipates the heat energy absorbed by the heat absorber to the compressed air heated by the second heat exchanger.

4. The compressed air energy storage device according to claim 3, characterized in that: The second heat exchanger is constituted by a three-fluid heat exchanger, and the heat storage medium heated by the first heat exchanger, the refrigerant flowing out of the radiator, and the compressed air supplied to the expander flow into the second heat exchanger.

5. The compressed air energy storage device according to claim 1, characterized in that: A secondary pressure accumulator tank is provided, which is different from the pressure accumulator tank storing the compressed air after heat exchange by the first heat exchanger, that is, the main pressure accumulator tank, and is connected to the compressed air inlet side of the first heat exchanger to store the compressed air compressed by the compressor. The second heat exchanger heats the compressed air flowing from the main accumulator tank into the expander by exchanging heat with the heat storage medium heated by the first heat exchanger. A control device is provided for driving the expander using the compressed air stored in the sub-accumulator tank, starting the flow of the heat storage medium heated by the first heat exchanger into the second heat exchanger, and then driving the expander using the compressed air stored in the main accumulator tank.

6. The compressed air energy storage device according to claim 5, characterized in that: The heat pump device absorbs heat from the heat storage medium that has undergone heat exchange in the second heat exchanger, and dissipates heat to at least one of compressed air flowing from the main accumulator tank into the expander and compressed air flowing from the sub-accumulator tank into the expander.

7. The compressed air energy storage device according to claim 6, characterized in that: The expander is a multi-stage expander having a first expansion stage and a second expansion stage, The second heat exchanger is respectively arranged at the inflow side of the first expansion stage and the second expansion stage, The heat pump device absorbs heat from the heat storage medium that has undergone heat exchange in the second heat exchanger, and dissipates heat to compressed air flowing from the main accumulator tank into the first expansion stage and from the first expansion stage into the second expansion stage.

8. The compressed air energy storage device according to claim 5, characterized in that: The heat pump device absorbs heat from the heat storage medium that has undergone heat exchange in the second heat exchanger, and dissipates heat to the heat storage medium supplied to the second heat exchanger.

9. The compressed air energy storage device according to claim 1, characterized in that: The heat pump device is a heat pump device that adopts a vapor compression cycle using a refrigerant.

10. The compressed air energy storage device according to claim 1, characterized in that: The heat storage medium is pressurized water.

11. A heat pump device used in a compressed air energy storage device, the compressed air energy storage device stores compressed air and compression heat obtained by a compressor compressing air, heats the compressed air by heat exchange between the compressed air at a heat exchanger and a heat storage medium that absorbs the compression heat, and uses the heated compressed air to drive an expander to generate electricity, wherein the heat pump device is characterized in that it has: a heat absorber that absorbs heat from the heat storage medium that has undergone heat exchange in the heat exchanger; and a radiator that radiates heat from the heat storage medium that has flowed into the heat exchanger.

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