Combined energy supply system and operation method thereof

Abstract

The invention relates to the technical field of energy storage. The invention discloses a combined energy supply system and an operation method thereof, and the system comprises an energy supply device which is connected with a heat consumer through a heat supply pipeline; the compressed air energy storage device is respectively connected with the energy supply device and the heat user through pipelines; when the compressed air energy storage device compresses air, the compressed air energy storage device is communicated with the heat user; when the compressed air energy storage device generates electricity, the compressed air energy storage device is communicated with the energy supply device. By connecting or disconnecting the compressed air energy storage device with the heat consumer or the energy supply device, the compressed air energy storage device can supply heat to the heat consumer by using the compressed heat of the air, a heat storage device can be avoided, the investment and operation cost is saved, meanwhile, the compressed air energy storage device can also generate electricity, and the energy consumption is reduced. And the peak regulation capability of the power grid is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of energy storage technology, and in particular to a combined energy supply system and an operation method thereof. Background Art

[0002] Adiabatic compressed air energy storage is a relatively mature and widely used non-supplementary compressed air energy storage technology. Its working principle is: during the energy storage process, while the compressor compresses the air into the air storage chamber, the heat exchanger is used to store the compression heat into the heat storage device, realizing the decoupled storage of electrical energy into pressure potential energy and compression heat energy; during the power generation process, the high-pressure air is released and heated by the stored compression heat to form high-temperature and high-pressure air to drive the turbine expander to generate electricity. Compared with traditional supplementary-fired compressed air energy storage, this technical route collects and utilizes compression heat to replace fossil fuel supplementary combustion, and the whole process has no carbon emissions, but a special heat storage device is required to store compression heat, which increases the initial investment and operating costs of the energy storage project. How to set up a heat storage device is a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of this, the present invention provides a combined energy supply system and an operation method thereof.

[0004] Specifically, the following technical solutions are included:

[0005] In a first aspect, a combined energy supply system is provided, comprising:

[0006] An energy supply device, wherein the energy supply device and the heat user are connected via a heating pipeline;

[0007] A compressed air energy storage device, wherein the compressed air energy storage device is respectively connected to the energy supply device and the heat user through pipelines;

[0008] When the compressed air energy storage device compresses air, the compressed air energy storage device is connected to the heat user;

[0009] When the compressed air energy storage device generates electricity, the compressed air energy storage device is connected to the energy supply device.

[0010] Preferably, the compressed air energy storage device comprises a compression module, a power generation module, a heat exchange module and an air storage module;

[0011] The compression module, the power generation module, the gas storage module, the energy supply device and the heat user are respectively connected to the heat exchange module.

[0012] Preferably, the system comprises a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve, a seventh valve, and an eighth valve;

[0013] The compression module is connected to the heat exchange module via a first valve;

[0014] The power generation module is connected to the heat exchange module through the second valve;

[0015] The heat user is connected to the heat exchange module via the third valve and the fourth valve;

[0016] The energy supply device is connected to the heat exchange module through the fifth valve and the sixth valve;

[0017] The gas storage module is connected to the heat exchange module through the seventh valve and the eighth valve.

[0018] Preferably, the gas storage module includes any one of a salt cavern gas storage device, a pressure tank gas storage device, and an artificial chamber gas storage device.

[0019] Preferably, the heat exchange module includes a plate heat exchanger or a shell and tube heat exchanger. When the compressed air energy storage device compresses air, the heat exchange module performs air-water heat exchange. When the compressed air energy storage device generates electricity, the heat exchange module performs air-steam heat exchange.

[0020] Preferably, the compressed air energy storage device is in single-stage mode or multi-stage mode.

[0021] Preferably, the compressed air energy storage device comprises a compression module, a power generation module, a heat exchange module and an air storage module;

[0022] The compression module includes N compressors, and the N compressors are arranged in stages;

[0023] The power generation module includes N expanders, and the N expanders are arranged in stages;

[0024] N heat exchangers are arranged in the heat exchange module;

[0025] For the heat exchangers of the 1st to the N-1th stages, each stage of the heat exchanger is respectively connected to the previous stage compressor, the next stage compressor, the previous stage expander, the next stage expander, the heat user and the energy supply device;

[0026] For the Nth stage heat exchanger, the heat exchanger is respectively connected to the Nth stage compressor, the first stage expander, the heat user, the energy supply device and the gas storage module.

[0027] Preferably, the energy supply device is a cogeneration unit.

[0028] In a second aspect, a method for operating a combined energy supply system is provided, which is applied to a combined energy supply system as described in the first aspect, and the method comprises:

[0029] When the compressed air energy storage device compresses air, the compressed air energy storage device is controlled to be connected to the heat user, and the heat supplied by the energy supply device to the heat user is controlled to be lower than a preset heat supply;

[0030] When the compressed air energy storage device generates electricity, the compressed air energy storage device is controlled to be connected to the energy supply device, and the heat supplied by the energy supply device to the heat user is controlled to be greater than or equal to the preset heat supply amount.

[0031] Preferably, the compressed air energy storage device comprises a compression module, a power generation module, a heat exchange module and an air storage module;

[0032] The method comprises:

[0033] When the compressed air energy storage device compresses air, the compression module, the heat user and the gas storage module are controlled to be connected to the heat exchange module respectively, and the energy supply device, the power generation module and the heat exchange module are disconnected, the compression module is controlled to compress the air, and the compressed air enters the gas storage module through the heat exchange module, the compressed air is controlled to exchange heat with the low-temperature water from the heat user in the heat exchange module, and the heat exchange module and the energy supply module simultaneously supply heat to the heat user;

[0034] When the compressed air energy storage device generates electricity, the compression module and the heat user are controlled to be disconnected from the heat exchange module respectively, and the energy supply device, the gas storage module, the power generation module and the heat exchange module are connected, the compressed air in the gas storage module is controlled to enter the power generation module through the heat exchange module, and the compressed air and the high-temperature steam from the energy supply module are controlled to exchange heat in the heat exchange module, and the energy supply module supplies heat to the heat user.

[0035] The beneficial effects of the technical solution provided by the present invention include at least:

[0036] The present application connects or interrupts the connection between the compressed air energy storage device and the heat user or energy supply device, so that the compressed air energy storage device can use the compressed heat of air to supply heat to the heat user, thereby avoiding the need to set up a heat storage device and saving investment and operating costs. At the same time, the compressed air energy storage device can also generate electricity, thereby enhancing the peak-shaving capacity of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 A schematic structural diagram of a single-stage compressed air energy storage device according to an embodiment of the present invention;

[0039] Figure 2 This is a schematic structural diagram of a multi-stage compressed air energy storage device according to an embodiment of the present invention.

[0040] The reference numerals in the figures represent respectively:

[0041] 1-electric motor; 2-compressor; 3-heat exchanger; 4-gas storage device; 5-expander; 6-generator; 7-energy supply device; 8-heat user; 9-first valve; 10-second valve; 11-third valve; 12-fourth valve; 13-fifth valve; 14-sixth valve; 15-seventh valve; 16-eighth valve.

[0042] The above drawings have shown clear embodiments of the present invention, which will be described in more detail below. These drawings and text descriptions are not intended to limit the scope of the present invention in any way, but to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Before further describing the embodiments of the present invention in detail, the directional nouns involved in the embodiments of the present invention, such as "upper part", "lower part", "side part", etc., are Figure 1 The directions shown in the figure are for reference only and do not limit the scope of protection of the present invention.

[0045] To make the technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0046] like Figure 1 and Figure 2 As shown, the present application provides a combined energy supply system, including: an energy supply device 7, the energy supply device 7 and the heat user 8 are connected through a heating pipeline; a compressed air energy storage device, the compressed air energy storage device is respectively connected to the energy supply device 7 and the heat user 8 through pipelines; when the compressed air energy storage device compresses air, the compressed air energy storage device and the heat user 8 are connected; when the compressed air energy storage device generates electricity, the compressed air energy storage device and the energy supply device 7 are connected.

[0047] Specifically, when the combined energy supply system needs to be peak-loaded, the power generation of the energy supply device 7 is reduced, and the amount of steam in the energy supply device 7 is reduced while reducing the amount of electricity connected to the combined energy supply system. The compressed air energy storage device compresses the air, and the heat generated during the compression process is transferred to the heat user 8; when the combined energy supply system needs to be peak-loaded, the power generation of the energy supply device 7 is increased, and the amount of steam in the energy supply device 7 is increased while increasing the amount of electricity connected to the combined energy supply system. A portion of the steam in the energy supply device 7 is extracted and provided to the compressed air in the compressed air energy storage device, and the compressed air performs work to generate electricity, further increasing the amount of electricity connected to the combined energy supply system. The present application connects or interrupts the connection between the compressed air energy storage device and the heat user 8 or the energy supply device 7, so that the compressed air energy storage device can use the compression heat of the air to supply heat to the heat user 8, thereby avoiding the need to set up a heat storage device, saving investment and operating costs. At the same time, the compressed air energy storage device can also generate electricity, thereby enhancing the peak-load load capability of the power grid.

[0048] Preferably, the compressed air energy storage device includes a compression module, a power generation module, a heat exchange module and a gas storage module; the compression module, the power generation module, the gas storage module, the energy supply device 7 and the heat user 8 are respectively connected to the heat exchange module.

[0049] Specifically, the compression module includes an electric motor 1 and a compressor 2. The power generation module includes an expander 5 and a generator 6. The heat exchange module includes a heat exchanger 3, which can be a plate heat exchanger or a shell and tube heat exchanger. When the compressed air energy storage device compresses air, the heat exchange module performs air-water heat exchange. When the compressed air energy storage device generates electricity, the heat exchange module performs air-steam heat exchange. The gas storage module includes a gas storage device 4, which can be any one of a salt cave gas storage device, a pressure tank gas storage device, and an artificial cavern gas storage device.

[0050] In one embodiment, the heat exchange module is a plate heat exchanger or a shell and tube heat exchanger, and air-water heat exchange or air-steam heat exchange can be performed at different times according to the operating requirements of the system. When air-water heat exchange is performed, the temperature of the inlet heat network circulating water is 30°C, and the temperature of the outlet heat network circulating water is 120°C. When air-steam heat exchange is performed, the inlet high-parameter steam can be extracted from the exhaust steam of the medium-pressure cylinder, and its temperature and pressure can be maintained at 290°C and 0.4MPa respectively. This heat exchange parameter can ensure the configuration of a heat exchanger with a reasonable end difference.

[0051] Specifically, the motor 1 is connected to the compressor 2 to provide power for the compressor 2. The expander 5 is connected to the generator 6, and the expander 5 drives the generator 6 to generate electricity.

[0052] Specifically, Figure 1 and Figure 2 As shown, the compressor 2, the expander 5, the gas storage device 4, the heat user 8, and the energy supply device 7 are respectively connected to the heat exchanger 3.

[0053] Preferably, Figure 1 and Figure 2 As shown, the combined energy supply system includes a first valve 9, a second valve 10, a third valve 11, a fourth valve 12, a fifth valve 13, a sixth valve 14, a seventh valve 15, and an eighth valve 16. The compression module is connected to the heat exchange module through the first valve 9; the power generation module is connected to the heat exchange module through the second valve 10; the heat user 8 is connected to the heat exchange module through the third valve 11 and the fourth valve 12; the energy supply device 7 is connected to the heat exchange module through the fifth valve 13 and the sixth valve 14; the gas storage module is connected to the heat exchange module through the seventh valve 15 and the eighth valve 16.

[0054] Specifically, when the combined energy supply system needs to be peak-loaded, the first valve 9, the third valve 11, the fourth valve 12, and the seventh valve 15 are opened, and the second valve 10, the fifth valve 13, the sixth valve 14, and the eighth valve 16 are closed. The power generation of the energy supply device 7 is reduced, and the amount of steam in the energy supply device 7 is reduced while reducing the amount of electricity connected to the grid of the combined energy supply system. The air enters the compressor 2 and begins to be compressed. The heat generated during the compression process is transferred to the heat user 8 through the heat exchange process between air and water in the heat exchanger. The circulating water of the heat network is used to take away the excess heat generated during the compression process to ensure the safe operation of the compressor 2. The compressed high-pressure air enters the gas storage device 4 for storage.

[0055] Specifically, when the combined energy supply system needs a peak, the first valve 9, the third valve 11, the fourth valve 12, and the seventh valve 15 are closed, and the second valve 10, the fifth valve 13, the sixth valve 14, and the eighth valve 16 are opened. The power generation of the energy supply device 7 increases, and the amount of steam of the energy supply device 7 increases while the amount of electricity connected to the grid of the combined energy supply system is increased. A portion of the steam of the energy supply device 7 is extracted and enters the heat exchanger 3, and the compressed air enters the heat exchanger 3 from the gas storage device 4. The heat required for the expansion of the compressed air is obtained in the heat exchanger 3 through the heat exchange process between air and steam. The expanded compressed air enters the expander 5 to drive the generator 6 to generate electricity, further increasing the amount of electricity connected to the grid of the combined energy supply system. The air after work is discharged into the atmosphere.

[0056] Preferably, the compressed air energy storage device is in single-stage mode or multi-stage mode.

[0057] Specifically, Figure 1 As shown, the compressed air energy storage device is a single-stage mode, and a compressor 2, an expander 5, and a heat exchanger 3 are provided one each. Figure 2 As shown, the compressed air energy storage device is a multi-stage mode, and a plurality of compressors 2, expanders 5, and heat exchangers 3 are respectively provided. Figure 2 The compressed air energy storage device is a two-stage mode, with two compressors 2, two expanders 5, and two heat exchangers 3 respectively provided.

[0058] Preferably, Figure 2 As shown, when the compressed air energy storage device is in a multi-stage mode, the compression module includes N compressors 2, and the N compressors 2 are arranged in stages; the power generation module includes N expanders 5, and the N expanders 5 are arranged in stages; N heat exchangers 3 are arranged in the heat exchange module; for the heat exchangers 3 of the 1st to N-1th stages, each stage of the heat exchanger 3 is respectively connected to the previous stage compressor 2, the next stage compressor 2, the previous stage expander 5, the next stage expander 5, the heat user 8 and the energy supply device 7; for the Nth stage heat exchanger 3, the heat exchanger 3 is respectively connected to the Nth stage compressor 2, the 1st stage expander 5, the heat user 8, the energy supply device 7 and the air storage module.

[0059] Specific, exemplary, such as Figure 2 As shown, the N compressors 2 are from the 1st stage to the Nth stage from left to right, the N expanders 5 are from the 1st stage to the Nth stage from right to left, and the N heat exchangers 3 are from the 1st stage to the Nth stage from left to right.

[0060] For example, Figure 2 As shown, the left heat exchanger 3 is a first-stage heat exchanger, and the right heat exchanger 3 is a second-stage heat exchanger. The left compressor 2 is a first-stage compressor, and the right compressor 2 is a second-stage compressor. The right expander 5 is a first-stage expander, and the left expander 5 is a second-stage expander. The first-stage heat exchanger is respectively connected to the first-stage compressor 2, the second-stage compressor 2, the first-stage expander 5, the second-stage expander 5, the heat user 8 and the energy supply device 7; the second-stage heat exchanger is the final-stage heat exchanger, and the second-stage heat exchanger is respectively connected to the second-stage compressor 2, the first-stage expander 5, the gas storage device 4, the heat user 8 and the energy supply device 7.

[0061] Preferably, the energy supply device 7 is a cogeneration unit, and specifically a thermal power unit.

[0062] The present application also provides an operation method of a combined energy supply system, which is applied to the above combined energy supply system, and the method includes:

[0063] When the compressed air energy storage device compresses air, the compressed air energy storage device is controlled to be connected to the heat user 8, and the energy supply device 7 is controlled to supply less heat to the heat user 8 than the preset heat supply;

[0064] When the compressed air energy storage device generates electricity, the compressed air energy storage device and the energy supply device 7 are controlled to be connected, and the heat supplied by the energy supply device 7 to the heat user 8 is controlled to be greater than or equal to the preset heat supply.

[0065] Specifically, the preset heating amount may be pre-set in the control system, and may be the amount of heat that the energy supply device 7 needs to supply to the heat user 8 when the compressed air energy storage device is not provided.

[0066] Specifically, in this embodiment, the motor 1, the compressor 2, the heat exchanger 3, the gas storage device 4, the expander 5, the generator 6, the energy supply device 7, the first valve 9, the second valve 10, the third valve 11, the fourth valve 12, the fifth valve 13, the sixth valve 14, the seventh valve 15, and the eighth valve 16 are respectively electrically connected or wirelessly connected to the control system, and the above-mentioned devices are adjusted through the control system to achieve the purpose of peak regulation.

[0067] Preferably, the method comprises:

[0068] When the compressed air energy storage device compresses air, the compression module, the heat user 8 and the gas storage module are controlled to be connected to the heat exchange module respectively, and the energy supply device 7, the power generation module and the heat exchange module are disconnected, the compression module is controlled to compress the air, and the compressed air enters the gas storage module through the heat exchange module, and the compressed air is controlled to exchange heat with the low-temperature water from the heat user 8 in the heat exchange module, and the heat exchange module and the energy supply module simultaneously supply heat to the heat user 8;

[0069] When the compressed air energy storage device generates electricity, the compression module and the heat user 8 are controlled to be disconnected from the heat exchange module respectively, and the energy supply device 7, the gas storage module, the power generation module and the heat exchange module are connected, and the compressed air in the gas storage module is controlled to enter the power generation module through the heat exchange module, and the compressed air in the heat exchange module is controlled to exchange heat with the high-temperature steam from the energy supply module in the heat exchange module, and the energy supply module supplies heat to the heat user 8.

[0070] Specifically, when the combined energy supply system needs to be peak-loaded, the first valve 9, the third valve 11, the fourth valve 12, and the seventh valve 15 are controlled to be opened, and the second valve 10, the fifth valve 13, the sixth valve 14, and the eighth valve 16 are controlled to be closed. The power generation of the energy supply device 7 is controlled to be reduced. At this time, the amount of steam in the energy supply device 7 will be reduced due to the reduction of the online power of the combined energy supply system. The compressor 2 is controlled to start, and the heat network circulating water flowing through the heat user 8 is controlled to enter the heat exchanger 3. The air enters the compressor 2 and starts to be compressed. The heat generated during the compression process is transferred to the heat user 8 through the heat exchange process between air and water in the heat exchanger 3, and the compressed high-pressure air enters the gas storage device 4 for storage. The excess heat generated during the compression process is taken away by the heat network circulating water to ensure the safe operation of the compressor 2.

[0071] Specifically, when the combined energy supply system needs a peak, the first valve 9, the third valve 11, the fourth valve 12, and the seventh valve 15 are controlled to be closed, and the second valve 10, the fifth valve 13, the sixth valve 14, and the eighth valve 16 are controlled to be opened. The power generation of the energy supply device 7 is controlled to increase. At this time, the amount of steam in the energy supply device 7 will increase due to the increase in the amount of electricity connected to the combined energy supply system. A portion of the steam in the energy supply device 7 is controlled to enter the heat exchanger 3, and the compressed air is controlled to enter the heat exchanger 3 from the gas storage device 4. The heat required for the expansion of the compressed air is obtained in the heat exchanger 3 through the heat exchange process between air and steam. The expanded compressed air enters the expander 5 to drive the generator 6 to generate electricity, further increasing the amount of electricity connected to the combined energy supply system. The air after work is discharged into the atmosphere.

[0072] In one example, an air purification device is also provided in the combined energy supply system, and the control purification device is provided at the inlet of the first stage compressor 2 or can also be provided at the inlet of each stage of the compressor 2. The air entering the compressor 2 should first enter the air purification device to remove particulate matter in the air at the inlet of the compressor 2, and can also remove water in the air and reduce condensed water in the exhaust of the compressor 2 to avoid damage to the compressor 2.

[0073] The combined function system of the present application does not need to be equipped with a special heat storage device to recover compression heat. The heat generated during the compression process can reduce the original amount of heating steam for the thermal power unit and improve the peak-shaving capacity of the thermal power unit itself. The expansion process is heated by high-parameter steam. Compared with traditional water-heat storage compressed air energy storage, high-parameter steam can heat the air to a higher temperature and improve the expansion work efficiency.

[0074] This application can couple the energy supply and operation characteristics of compressed air energy storage and thermal power units, and can give full play to the complementary advantages of thermal power units and compressed air energy storage power generation. When the system needs peak load regulation, the compressed air energy storage device is activated to compress the air to generate compression heat, which compensates for the reduction in heat supply of thermal power units caused by reducing power generation. When the system needs a peak load, the compressed air energy storage device is activated to use the thermal power device to heat the compressed air to expand and do work, which not only meets the needs of 8 heat users but also increases the system's online power. Based on the existing thermal power peak load regulation boundaries, this application can increase the peak load regulation depth of the unit and increase the top peak output of the unit. At the same time, by utilizing the powerful heat storage capacity of the heating pipeline network, the configuration and investment of the heat storage device in the compressed air energy storage system can be eliminated, thereby improving the feasibility of the application of compressed air energy storage technology.

[0075] In the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0076] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The description and examples are to be considered exemplary only.

[0077] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A combined energy supply system, characterized in that: include: An energy supply device, wherein the energy supply device and the heat user are connected via a heating pipeline; A compressed air energy storage device, wherein the compressed air energy storage device is respectively connected to the energy supply device and the heat user through pipelines; When the compressed air energy storage device compresses air, the compressed air energy storage device is connected to the heat user; When the compressed air energy storage device generates electricity, the compressed air energy storage device is connected to the energy supply device.

2. The system according to claim 1, characterized in that The compressed air energy storage device comprises a compression module, a power generation module, a heat exchange module and an air storage module; The compression module, the power generation module, the gas storage module, the energy supply device and the heat user are respectively connected to the heat exchange module.

3. The system according to claim 2, characterized in that The system includes a first valve, a second valve, a third valve, a fourth valve, a fifth valve, a sixth valve, a seventh valve, and an eighth valve; The compression module is connected to the heat exchange module via a first valve; The power generation module is connected to the heat exchange module through the second valve; The heat user is connected to the heat exchange module via the third valve and the fourth valve; The energy supply device is connected to the heat exchange module through the fifth valve and the sixth valve; The gas storage module is connected to the heat exchange module through the seventh valve and the eighth valve.

4. The system according to claim 2, characterized in that The gas storage module includes any one of a salt cavern gas storage device, a pressure tank gas storage device, and an artificial chamber gas storage device.

5. The system according to claim 2, characterized in that The heat exchange module includes a plate heat exchanger or a shell and tube heat exchanger. When the compressed air energy storage device compresses air, the heat exchange module performs air-water heat exchange. When the compressed air energy storage device generates electricity, the heat exchange module performs air-steam heat exchange.

6. The system according to claim 1, characterized in that The compressed air energy storage device is in single-stage mode or multi-stage mode.

7. The system according to claim 1, characterized in that The compressed air energy storage device comprises a compression module, a power generation module, a heat exchange module and an air storage module; The compression module includes N compressors, and the N compressors are arranged in stages; The power generation module includes N expanders, and the N expanders are arranged in stages; N heat exchangers are arranged in the heat exchange module; For the heat exchangers of the 1st to the N-1th stages, each stage of the heat exchanger is respectively connected to the previous stage compressor, the next stage compressor, the previous stage expander, the next stage expander, the heat user and the energy supply device; For the Nth stage heat exchanger, the heat exchanger is respectively connected to the Nth stage compressor, the first stage expander, the heat user, the energy supply device and the gas storage module.

8. The system according to claim 1, characterized in that The energy supply device is a cogeneration unit.

9. A method for operating a combined energy supply system, characterized in that: Applied to a combined energy supply system as claimed in any one of claims 1 to 8, the method comprises: When the compressed air energy storage device compresses air, the compressed air energy storage device is controlled to be connected to the heat user, and the heat supplied by the energy supply device to the heat user is controlled to be lower than a preset heat supply; When the compressed air energy storage device generates electricity, the compressed air energy storage device is controlled to be connected to the energy supply device, and the heat supplied by the energy supply device to the heat user is controlled to be greater than or equal to the preset heat supply amount.

10. The method according to claim 9, characterized in that The compressed air energy storage device comprises a compression module, a power generation module, a heat exchange module and an air storage module; The method comprises: When the compressed air energy storage device compresses air, the compression module, the heat user and the gas storage module are controlled to be connected to the heat exchange module respectively, and the energy supply device, the power generation module and the heat exchange module are disconnected, the compression module is controlled to compress the air, and the compressed air enters the gas storage module through the heat exchange module, the compressed air is controlled to exchange heat with the low-temperature water from the heat user in the heat exchange module, and the heat exchange module and the energy supply module simultaneously supply heat to the heat user; When the compressed air energy storage device generates electricity, the compression module and the heat user are controlled to be disconnected from the heat exchange module respectively, and the energy supply device, the gas storage module, the power generation module and the heat exchange module are connected, the compressed air in the gas storage module is controlled to enter the power generation module through the heat exchange module, and the compressed air and the high-temperature steam from the energy supply module are controlled to exchange heat in the heat exchange module, and the energy supply module supplies heat to the heat user.

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