Air energy storage system

Abstract

Provided is an air energy storage system capable of suppressing a decrease in the temperature of a heat medium stored in a heat medium tank and increasing the power of an expander. The air energy storage system comprises: compressors 2A, 2B which compress air; heat exchangers 3A, 3B which perform heat exchange between the air discharged from the compressors 2A, 2B and a heat medium to cool the air and heat the heat medium; an air tank 5 which stores the air cooled by the heat exchangers 3A, 3B; a heat medium tank 6 which stores the heat medium heated by the heat exchangers 3A, 3B; heat exchangers 7A, 7B which perform heat exchange between the air stored in the air tank 5 and the heat medium stored in the heat medium tank 6 to heat the air and cool the heat medium; and expanders 8A, 8B which are driven by the air heated by the heat exchangers 7A, 7B, said air energy storage system further comprising a heating flow passage 21 which is provided on an outer wall of the heat medium tank 6 and through which the air discharged from the compressor 2B flows.

Description

Air energy storage system

[0001] The present invention relates to an air energy storage system, and more specifically to a compressed air energy storage system or a liquid air energy storage system.

[0002] In recent years, compressed air energy storage systems or liquid air energy storage systems have been proposed, in which compressed air generated by a compressor or liquid air obtained by liquefying said compressed air is stored in an air tank, and the stored compressed air or gaseous air obtained by vaporizing the stored liquid air is used to drive an expander. One of the applications of such systems is that, since power generation using renewable energy such as wind power and solar power depends on weather conditions, generated electrical energy is converted into compressed air energy or liquid air energy for storage, and is reconverted into electrical energy when needed.

[0003] The compressed air energy storage system disclosed in Patent Document 1 comprises a first heat exchanger that performs heat exchange between compressed air generated by a compressor and a heat medium (specifically, water) to cool the compressed air and heat the heat medium. This recovers heat from the compressed air generated by the compressor and lowers the temperature of the compressed air stored in the air tank. Therefore, it is possible to reduce the required capacity of the air tank.

[0004] The compressed air energy storage system disclosed in Patent Document 1 further comprises a heat medium tank that stores the heat medium heated by the first heat exchanger, and a second heat exchanger that performs heat exchange between the compressed air stored in the air tank and the heat medium stored in the heat medium tank to heat the compressed air and cool the heat medium. This uses the recovered heat to heat the compressed air stored in the air tank, and raises the temperature of the compressed air used to drive the expander. Therefore, it is possible to increase the output power of the expander.

[0005] Japanese Unexamined Patent Application Publication No. 2019-143608

[0006] However, the above-mentioned conventional technology has room for improvement as follows: The heat transfer medium stored in the heat transfer medium tank loses heat to the outer wall of the tank, causing its temperature to drop. In particular, when the inside of the heat transfer medium tank is pressurized to prevent vaporization of the heat transfer medium, as described in Patent Document 1, it is necessary to increase the strength of the outer wall of the heat transfer medium tank, and the thickness of at least a part of the outer wall must be increased. As a result, the heat capacity of the outer wall of the heat transfer medium tank increases, and the temperature of the heat transfer medium stored in the heat transfer medium tank tends to drop. Consequently, the temperature of the compressor air heated by the heat transfer medium also decreases, and the power of the expander decreases.

[0007] One of the objectives of this invention is to suppress the decrease in the temperature of the heat transfer medium stored in the heat transfer medium tank, thereby increasing the power of the expander.

[0008] To solve the above problems, the configuration described in the claims is applied. The present invention includes a plurality of means for solving the above problems, but to give one example, an air energy storage system comprising: a compressor for compressing air; a first heat exchanger that performs heat exchange between the air discharged from the compressor and a heat medium to cool the air and heat the heat medium; an air tank for storing the air cooled by the first heat exchanger; a heat medium tank for storing the heat medium heated by the first heat exchanger; a second heat exchanger that performs heat exchange between the air stored in the air tank and the heat medium stored in the heat medium tank to heat the air and cool the heat medium; and an expander driven by the air heated by the second heat exchanger, wherein the heat medium tank is provided with a heating channel through which the air discharged from the compressor flows.

[0009] According to the present invention, the decrease in the temperature of the heat medium stored in the heat medium tank can be suppressed, thereby increasing the power of the expander.

[0010] Furthermore, other issues, structures, and effects not mentioned above will be clarified in the following explanation.

[0011] This is a diagram showing the configuration of a compressed air energy storage system in the first embodiment of the present invention. This is a top view showing the structure of a heating channel provided on the upper part of the outer wall of a heat transfer medium tank in the first embodiment of the present invention. This is a block diagram showing a control device and related equipment in the first embodiment of the present invention. This is a diagram showing the configuration of a compressed air energy storage system in the second embodiment of the present invention. This is a diagram showing the configuration of a compressed air energy storage system in the third embodiment of the present invention. This is a diagram showing the configuration of a liquid air energy storage system in the fourth embodiment of the present invention.

[0012] A first embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is a diagram showing the configuration of the compressed air energy storage system in this embodiment. Figure 2 is a top view showing the structure of the heating channel provided on the upper part of the outer wall of the heat transfer medium tank in this embodiment. Figure 3 is a block diagram showing the control device and related equipment in this embodiment.

[0013] The compressed air energy storage system of this embodiment comprises an electric motor 1A, a compressor 2A driven by the electric motor 1A to compress air, a heat exchanger 3A (first heat exchanger) that performs heat exchange between the compressed air discharged from the compressor 2A and a heat transfer medium (specifically, water) to cool the compressed air and heat the heat transfer medium, an electric motor 1B, a compressor 2B driven by the electric motor 1B to further compress the compressed air cooled in the heat exchanger 3A, a heat exchanger 3B (first heat exchanger) that performs heat exchange between the compressed air discharged from the compressor 2B and a heat transfer medium to cool the compressed air and heat the heat transfer medium, and an air tank 5 that stores the compressed air that has been cooled in the heat exchanger 3B and introduced through a check valve 4.

[0014] This makes it possible to convert electrical energy generated by wind power or solar power into compressed air energy and store it. In addition, heat is recovered from the compressed air generated by compressors 2A and 2B, lowering the temperature of the compressed air stored in the air tank 5. As a result, it is possible to reduce the capacity of the air tank 5.

[0015] The compressed air energy storage system of this embodiment further comprises a heat medium tank 6 for storing the heat medium heated by heat exchangers 3A and 3B; a heat exchanger 7A (second heat exchanger) that performs heat exchange between the compressed air stored in the air tank 5 and the heat medium stored in the heat medium tank 6 to heat the compressed air and cool the heat medium; an expander 8A driven by the compressed air heated by the heat exchanger 7A; a generator 9A driven by the expander 8A; a heat exchanger 7B (second heat exchanger) that performs heat exchange between the compressed air discharged from the expander 8A and the heat medium stored in the heat medium tank 6 to heat the compressed air and cool the heat medium; an expander 8B driven by the compressed air heated by the heat exchanger 7B; and a generator 9B driven by the expander 8B.

[0016] This makes it possible to convert compressed air energy into electrical energy when needed. Furthermore, the recovered heat is used to heat the compressed air stored in the air tank 5, increasing the temperature of the compressed air used to drive the expanders 8A and 8B. Therefore, it is possible to increase the power output of the expanders 8A and 8B.

[0017] The heat transfer fluid tank 6 is made of stainless steel, for example, and has a circular bottom plate 10, cylindrical side plates 11, and an annular flange 12, which are welded together. The heat transfer fluid tank 6 further has a removable cover plate 13 attached to the upper side of the side plates 11 and flange 12 using, for example, a plurality of bolts (not shown).

[0018] The heat transfer medium tank 6 stores the heat transfer medium in such a way that it occupies, for example, 90% of the tank's internal volume, and that it forms a temperature stratification where the heat transfer medium has a higher temperature in the upper layer and a lower temperature in the lower layer. Pump 14A supplies low-temperature heat transfer medium from the first outlet at the bottom of the heat transfer medium tank 6 to the heat exchangers 3A and 3B, and high-temperature heat transfer medium from the heat exchangers 3A and 3B to the first inlet at the top of the heat transfer medium tank 6. Pump 14B supplies high-temperature heat transfer medium from the second outlet at the top of the heat transfer medium tank 6 to the heat exchangers 7A and 7B, and low-temperature heat transfer medium from the heat exchangers 7A and 7B to the second inlet at the bottom of the heat transfer medium tank 6. The flow velocity of the heat transfer medium flowing into or out of the heat transfer medium tank 6 is set to a range of, for example, 0.1 to 0.3 m / s in order to maintain the temperature stratification of the heat transfer medium within the heat transfer medium tank 6.

[0019] The compressed air energy storage system of this embodiment further comprises an on-off valve 15 provided between the air tank 5 and the heat exchanger 7A, and a control device 16 that controls the electric motors 1A, 1B, pumps 14A, 14B, and the on-off valve 15, etc. The control device 16, although not shown, includes a processor that executes processing according to a program, and a memory for storing programs and data.

[0020] The control device 16 executes a compressor operation mode and an expander operation mode. In the compressor operation mode, the control device 16 drives the electric motors 1A and 1B and the pump 14A, and closes the on-off valve 15. As a result, the compressed air generated by the compressors 2A and 2B and cooled by the heat exchangers 3A and 3B is stored in the air tank 5. In addition, the heat transfer medium heated by the heat exchangers 3A and 3B is stored in the heat transfer medium tank 6. In other words, the low-temperature layer and high-temperature layer of the temperature stratification of the heat transfer medium in the heat transfer medium tank 6 decrease. The control device 16 terminates the compressor operation mode when the temperature of the heat transfer medium detected by a temperature sensor (not shown) located near the first outlet on the lower side of the heat transfer medium tank 6 rises to a predetermined high value (in other words, when a high-temperature layer has formed up to the vicinity of the first outlet on the lower side of the heat transfer medium tank 6).

[0021] In the expander operation mode, the control device 16 drives the pump 14B and opens the on-off valve 15. As a result, the expanders 8A and 8B are driven using compressed air stored in the air tank 5 and heated by the heat exchangers 7A and 7B, and the generators 9A and 9B are driven. At this time, the high-temperature layer and the low-temperature layer of the temperature stratification of the heat medium in the heat medium tank 6 decrease. The control device 16 terminates the expander operation mode when the temperature of the heat medium detected by a temperature sensor (not shown) located near the upper second outlet of the heat medium tank 6 drops to a predetermined low value (in other words, when a low-temperature layer has formed up to the vicinity of the upper second outlet of the heat medium tank 6).

[0022] The inside of the heat transfer medium tank 6 is pressurized by a pressurizing device 17 to prevent the heat transfer medium from vaporizing. The pressurizing device 17 is configured to supply nitrogen gas to the space located above the heat transfer medium inside the heat transfer medium tank 6, and includes a nitrogen cylinder 18 for storing nitrogen gas, and a pressure regulating valve 19 and a pressure sensor 20 arranged in the path between the nitrogen cylinder 18 and the heat transfer medium tank 6. The opening of the pressure regulating valve 19 is adjusted by the control device 16 or manually according to the pressure detected by the pressure sensor 20. This maintains the pressure inside the heat transfer medium tank 6 at a target value. For example, if the target pressure is 0.9 MPaG, the saturation temperature of the heat transfer medium (water) becomes 180°C, preventing vaporization of the heat transfer medium (water) used at temperatures below 180°C.

[0023] As described above, since the inside of the heat transfer medium tank 6 is pressurized by the pressurizing device 17, it is necessary to increase the strength of the outer wall of the heat transfer medium tank 6, and the thickness of the bottom plate 10, side plates 11, flange 12, and lid plate 13 has been increased. In other words, the heat capacity of the outer wall of the heat transfer medium tank 6 has been increased. As a result, the heat transfer medium stored in the heat transfer medium tank 6 is prone to losing heat to the outer wall of the heat transfer medium tank 6, causing its temperature to drop.

[0024] Therefore, the compressed air energy storage system of this embodiment further comprises a heating channel 21 provided on the outer wall of the heat medium tank 6, an introduction channel 23 connected to the heating channel 21 and branching off from the channel 22A (first channel) between the compressor 2B and the heat exchanger 3B, and an outlet channel 24 connected to the heating channel 21 and merging with the channel 22B (second channel) between the heat exchanger 3B and the air tank 5. That is, the heating channel 21 is arranged in parallel with the heat exchanger 3B. A portion of the compressed air discharged from the compressor 2B is introduced into the heating channel 21 via the introduction channel 23 and flows through it, and the compressed air that has flowed through the heating channel 21 is led out to the channel 22B via the outlet channel 24. As described above, the heat medium tank 6 stores the heat medium in such a way that it forms a temperature stratification, so the heating channel 21 is provided only on the upper part of the outer wall of the heat medium tank 6 (specifically, the lid plate 13). The heating channel 21 is composed of, for example, an arc-shaped half-pipe jacket.

[0025] The compressed air energy storage system of this embodiment further includes a flow control valve 25 provided in the introduction channel 23 (or the outlet channel 24) to adjust the flow rate of compressed air, a temperature sensor 26 (first temperature sensor) for detecting the temperature of the outer wall of the heat medium tank 6, and a temperature sensor 27 (second temperature sensor) for detecting the temperature of the heat medium heated by the heat exchangers 3A and 3B. As described above, the heat medium tank 6 stores the heat medium in such a way that it forms a temperature stratification, so the temperature sensor 26 is positioned on the upper part of the outer wall of the heat medium tank 6 (for example, at the interface position of the heat medium on the side plate 11).

[0026] The control device 16 sets the temperature detected by the temperature sensor 27 as the target temperature and controls the flow control valve 25 so that the temperature detected by the temperature sensor 26 becomes the target temperature. This reduces the difference between the temperature of the heat medium flowing from the heat exchangers 3A and 3B into the heat medium tank 6 and the temperature of the upper part of the outer wall of the heat medium tank 6.

[0027] As described above, in this embodiment, a heating channel 21 is provided on the outer wall of the heat medium tank 6, and the outer wall of the heat medium tank 6 can be heated by flowing compressed air discharged from the compressor 2B through the heating channel 21. Although the heating channel 21 is provided only on the lid plate 13 of the heat medium tank 6, not only the lid plate 13 but also the upper parts of the flange 12 and side plates 11 (near the interface of the heat medium) are heated by heat conduction. This makes it possible to suppress the decrease in the temperature of the heat medium stored in the heat medium tank 6. As a result, the decrease in the temperature of the compressed air heated by the heat medium is also suppressed, and the power of the expander can be increased.

[0028] A second embodiment of the present invention will be described with reference to Figure 4. Figure 4 is a diagram showing the configuration of the compressed air energy storage system in this embodiment. In this embodiment, parts equivalent to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0029] The compressed air energy storage system of this embodiment further includes a heat exchanger 28 (third heat exchanger) that performs heat exchange between the compressed air led out from the heating channel 21 and the heat transfer medium to cool the compressed air and heat the heat transfer medium.

[0030] The heat transfer medium tank 6 stores not only the heat transfer medium heated by the heat exchangers 3A and 3B, but also the heat transfer medium heated by the heat exchanger 28. Specifically, the pump 14A supplies low-temperature heat transfer medium from the first outlet at the bottom of the heat transfer medium tank 6 to the heat exchangers 3A, 3B, and 28, and high-temperature heat transfer medium is supplied from the heat exchangers 3A, 3B, and 28 to the first inlet at the top of the heat transfer medium tank 6.

[0031] In this embodiment as well, similar to the first embodiment, the decrease in the temperature of the heat medium stored in the heat medium tank 6 can be suppressed, thereby increasing the power of the expander.

[0032] In the first embodiment, heat is not recovered and utilized from the compressed air discharged from the heating channel 21, but in this embodiment, heat is recovered and utilized from the compressed air discharged from the heating channel 21. Therefore, in this embodiment, compared to the first embodiment, the temperature of the compressed air stored in the air tank 5 can be lowered, and the capacity of the air tank 5 can be reduced. Also, compared to the first embodiment, the temperature of the compressed air used to drive the expander can be increased, and the power of the expander can be increased.

[0033] In the first and second embodiments, the control device 16 was described using the temperature detected by the temperature sensor 27 as the target temperature, but it is not limited to this, and a preset target temperature may be used. In other words, the compressed air energy storage system does not need to be equipped with a temperature sensor 27.

[0034] Furthermore, in the first and second embodiments, the control device 16 was described as having a function to control the flow rate adjustment valve 25 so that the temperature detected by the temperature sensor 27 becomes the target temperature (i.e., a function to vary the flow rate of compressed air in the heating channel 21), but it is not limited to this, and it does not have to have this function. In other words, the flow rate of compressed air in the heating channel 21 may be fixed.

[0035] A third embodiment of the present invention will be described with reference to Figure 5. Figure 5 is a diagram showing the configuration of the compressed air energy storage system in this embodiment. In this embodiment, parts equivalent to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0036] In this embodiment, the introduction channel 23A is connected between the compressor 2B and the heating channel 21, and all of the compressed air discharged from the compressor 2B is introduced into the heating channel 21. The discharge channel 24A is connected between the heating channel 21 and the heat exchanger 3B, and the compressed air that has flowed through the heating channel 21 is discharged into the heat exchanger 3B. In other words, the heating channel 21 is arranged in series with respect to the heat exchanger 3B.

[0037] In this embodiment as well, similar to the first embodiment, the decrease in the temperature of the heat medium stored in the heat medium tank 6 can be suppressed, thereby increasing the power of the expander.

[0038] In the first embodiment, heat is not recovered and utilized from the compressed air discharged from the heating channel 21, but in this embodiment, heat is recovered and utilized from the compressed air discharged from the heating channel 21. Therefore, in this embodiment, compared to the first embodiment, the temperature of the compressed air stored in the air tank 5 can be lowered, and the capacity of the air tank 5 can be reduced. Also, compared to the first embodiment, the temperature of the compressed air used to drive the expander can be increased, and the power of the expander can be increased.

[0039] Unlike the first and second embodiments, this embodiment does not include a flow control valve 25 and temperature sensors 26 and 27. Therefore, costs can be reduced compared to the first and second embodiments.

[0040] A fourth embodiment of the present invention will be described with reference to Figure 6. Figure 6 is a diagram showing the configuration of the liquid air energy storage system in this embodiment. In this embodiment, parts equivalent to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0041] In this embodiment, the air tank 5A stores liquid air obtained by liquefying compressed air. Therefore, the liquid air energy storage system of this embodiment includes a booster compressor 29 that further compresses the compressed air cooled by the heat exchanger 3B, and a heat exchanger 30 that has the function of cooling and liquefying the compressed air introduced from the booster compressor 29 via the check valve 4 to about -160°C by heat exchange with an internal refrigerant storage body.

[0042] The air tank 5A stores the liquid air, which has been liquefied in the heat exchanger 30 and introduced through the pressure reducing valve 31A, at a pressure of approximately 1.5 to 2 MPa, and separates the gaseous air mixed in with the liquid air. The heat exchanger 30 has the function of cooling the gaseous air separated in the air tank 5A and introduced through the pressure reducing valve 31B by heat exchange with the internal refrigerant storage body, and leading the cooled gaseous air to the upstream side of the booster compressor 29.

[0043] In the present embodiment, the heat exchanger 7A performs heat exchange between gaseous air obtained by vaporizing liquid air stored in the air tank 5A and a heat medium stored in the heat medium tank 6, to heat the gaseous air and cool the heat medium. The expander 8A is driven by the gaseous air heated by the heat exchanger 7A. The heat exchanger 7B performs heat exchange between the gaseous air discharged from the expander 8A and the heat medium stored in the heat medium tank 6, to heat the gaseous air and cool the heat medium. The expander 8B is driven by the gaseous air heated by the heat exchanger 7B. Therefore, the heat exchanger 30 has a function of heating liquid air stored in the air tank 5A and introduced via the pump 14C and the pressure reducing valve 31C to about room temperature to vaporize the liquid air, and discharging the vaporized liquid air to the heat exchanger 7A via the on-off valve 15.

[0044] In the liquid air energy storage system of the present embodiment, similarly to the compressed air energy storage system, a decrease in the temperature of the heat medium stored in the heat medium tank 6 can be suppressed, and the power of the expander can be increased. In addition, compared with the compressed air energy storage system, the liquid air energy storage system can greatly reduce the capacity of the air tank and the installation space. Therefore, there are fewer installation restrictions, and cost reduction can be achieved.

[0045] In the present embodiment, the compressed air energy storage system of the first embodiment is modified into the liquid air energy storage system, but the compressed air energy storage systems of the second and third embodiments can also be similarly modified into liquid air energy storage systems.

[0046] In the first to fourth embodiments, the air energy storage system was described using an example where the system includes a heat medium tank 6 that stores both a low-temperature heat medium and a high-temperature heat medium. However, the system is not limited to this, and may include a first heat medium tank for storing a low-temperature heat medium and a second heat medium tank for storing a high-temperature heat medium. The heat medium stored in the first heat medium tank is supplied to heat exchangers 3A and 3B, and the heat medium heated in heat exchangers 3A and 3B is supplied to the second heat medium tank. The heat medium stored in the second heat medium tank is supplied to heat exchangers 7A and 7B, and the heat medium cooled in heat exchangers 7A and 7B is supplied to the first heat medium tank. In this modified example, the second heat medium tank does not need to store the heat medium in such a way that it forms a temperature stratification. Therefore, the arrangement of the heating flow path does not need to be limited to the upper part of the outer wall of the second heat medium tank.

[0047] Furthermore, although the first to fourth embodiments were described using the case where the heat transfer medium is water as an example, other liquids may be used. Also, although the first to fourth embodiments were described using the case where there are multiple sets of compressors and first heat exchangers as an example, there may be only one set. Also, although the first to fourth embodiments were described using the case where there are multiple sets of expanders and second heat exchangers as an example, there may be only one set. Also, although the first to fourth embodiments were described using the case where the air energy storage system includes an electric motor that drives the compressor and a generator driven by the expander as an example, these may not be included.

[0048] 1A, 1B...Electric motor, 2A, 2B...Compressor, 3A, 3B...Heat exchanger (first heat exchanger), 5, 5A...Air tank, 6...Heat transfer medium tank, 7A, 7B...Heat exchanger (second heat exchanger), 8A, 8B...Expander, 9A, 9B...Generator, 10...Bottom plate, 11...Side plate, 12...Flange, 13...Cover plate, 16...Control device, 21...Heating channel, 22A...Channel (first channel), 22B...Channel (second channel), 23, 23A...Inlet channel, 24, 24A...Outlet channel, 25...Flow control valve, 26...Temperature sensor (first temperature sensor), 27...Temperature sensor (second temperature sensor), 28...Heat exchanger 28 (third heat exchanger)

Claims

1. An air energy storage system comprising: a compressor for compressing air; a first heat exchanger for cooling the air and heating the heat medium by exchanging heat between the air discharged from the compressor and a heat medium; an air tank for storing the air cooled by the first heat exchanger; a heat medium tank for storing the heat medium heated by the first heat exchanger; a second heat exchanger for heating the air and cooling the heat medium by exchanging heat between the air stored in the air tank and the heat medium stored in the heat medium tank; and an expander driven by the air heated by the second heat exchanger, wherein the system is provided with a heating channel on the outer wall of the heat medium tank through which the air discharged from the compressor flows.

2. An air energy storage system according to claim 1, comprising: an introduction channel connected to branch off from a first flow path between the compressor and the first heat exchanger and connected to the heating channel, for introducing a portion of the air discharged from the compressor into the heating channel; and an outlet channel connected to the heating channel and connected to merge with a second flow path between the first heat exchanger and the air tank, for leading the air that has flowed through the heating channel into the second flow path.

3. An air energy storage system according to claim 2, comprising: a flow control valve provided in the introduction channel or the outlet channel for adjusting the flow rate of air; a first temperature sensor for detecting the temperature of the outer wall of the heat transfer medium tank; and a control device for controlling the flow control valve so that the temperature detected by the first temperature sensor becomes the target temperature.

4. An air energy storage system according to claim 3, comprising a second temperature sensor for detecting the temperature of a heat medium heated by the first heat exchanger, wherein the control device sets the temperature detected by the second temperature sensor as the target temperature.

5. An air energy storage system according to claim 2, comprising a third heat exchanger that performs heat exchange between air discharged from the heating channel and a heat medium to cool the air and heat the heat medium, wherein the heat medium tank stores the heat medium heated by the third heat exchanger.

6. An air energy storage system according to claim 1, comprising: an introduction channel connected between the compressor and the heating channel, which introduces all of the compressed air discharged from the compressor into the heating channel; and an outlet channel connected between the heating channel and the first heat exchanger, which leads the compressed air that has flowed through the heating channel to the first heat exchanger.

7. An air energy storage system according to claim 1, wherein the heat medium tank stores the heat medium in such a way that the temperature of the heat medium forms a layered structure with the upper layer being higher and the lower layer lower, and the heating channel is provided only on the upper part of the outer wall of the heat medium tank.

8. An air energy storage system according to claim 1, characterized by comprising: an electric motor for driving the compressor; and a generator driven by the expander.

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