Combined heat and power storage system based on high-temperature metal phase change heat storage

Abstract

The present invention relates to a combined heat and power storage system based on high-temperature metal phase change heat storage, comprising a storage tank for storing phase change heat storage material, a heat exchange tube arranged in the storage tank, and a circulating heating component for circulating heating a heat carrier. The phase change heat storage material is selected from one or more of copper heat storage body, aluminum heat storage body, and zinc heat storage body. The heat carrier is selected from one of metal sodium and metal tin. The circulating heating component comprises a low-temperature heater for preliminary heating of the heat carrier, a first delivery pump and a second delivery pump for delivering the heat carrier, a high-temperature heater for final heating of the heat carrier, a first three-way valve, and a second three-way valve. A combined heat and power component is also provided on the high-temperature heater. Copper heat storage body, aluminum heat storage body, and zinc heat storage body are used as phase change heat storage materials in the storage tank. The energy storage density is high, which can significantly improve the energy conversion efficiency and economy. The heat transfer efficiency is much higher than that of the traditional one. A combined cycle of gas power cycle and steam power cycle is adopted, and the conversion efficiency is high.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage equipment, and more particularly to a combined heat and power storage system based on high-temperature metal phase change heat storage. Background Art

[0002] To balance the peaks and valleys of grid load during the day and night and maximize energy utilization, various energy storage technologies have been developed and researched. In particular, with the rise of the concept of carbon neutrality in recent years, the scale of power generation from unstable renewable energy sources such as wind and solar has increased significantly. To absorb this unstable energy, the demand for power storage technology has greatly increased. Furthermore, industrial production consumes not only electricity but also significant amounts of heat. Therefore, using clean electricity to supply heat has become an integral part of carbon neutrality. Against this backdrop, combined heat and power systems based on high-temperature heat storage have begun to gain momentum.

[0003] At present, the cogeneration system based on high-temperature heat storage is represented by the molten salt system, which uses a mixture of inorganic salts such as nitrates as a heat carrier and heat storage material. The operating temperature is not high enough, with the highest being around 550°C. The sensible heat of the molten salt is also used during operation, and the energy storage density is not high enough. These factors affect the energy conversion efficiency and economy of the system. The use of inorganic salts such as sodium chloride can operate at higher temperatures, but problems such as high-temperature corrosion of materials need to be solved. In order to overcome the shortcomings of the current molten salt heat storage system, such as low energy conversion efficiency and low energy storage density, the present invention proposes a cogeneration system based on metal high-temperature phase change heat storage. Summary of the Invention

[0004] In order to overcome the shortcomings of the current molten salt heat storage system, such as low energy conversion efficiency and low energy storage density, and to address the problems existing in the prior art, the present invention provides a combined heat and power storage system based on high-temperature metal phase change heat storage.

[0005] To solve the above problems, the present invention adopts the following technical solutions.

[0006] A combined heat and power storage system based on high-temperature metal phase change heat storage includes a storage tank for storing phase change heat storage material, a heat exchange tube arranged in the storage tank, and a circulating heating component for circulating heating of a heat carrier. The phase change heat storage material is selected from one or more of copper heat storage body, aluminum heat storage body, and zinc heat storage body. The heat carrier is selected from one of metallic sodium and metallic tin.

[0007] The circulating heating assembly includes a low-temperature heater for preliminarily heating the heat carrier, a first delivery pump and a second delivery pump for delivering the heat carrier, a high-temperature heater for finally heating the heat carrier, a first three-way valve, and a second three-way valve. One end of the heat exchange tube passes through the storage tank and is connected to the first end of the first three-way valve, the other end of the heat exchange tube passes through the storage tank and is connected to the first end of the second three-way valve, the second end of the first three-way valve is connected to the output end of the first delivery pump, the input end of the first delivery pump is connected to the output end of the low-temperature heater, the input end of the low-temperature heater is connected to the second end of the second three-way valve, the third end of the second three-way valve is connected to the output end of the second delivery pump, the input end of the second delivery pump is connected to the output end of the high-temperature heater, and the input end of the high-temperature heater is connected to the third end of the first three-way valve. In addition, a cogeneration assembly is also provided on the high-temperature heater.

[0008] The cogeneration component includes a compressor, a turbine, a regenerator, and a waste heat boiler. The gas output end of the compressor and the gas output end of the turbine are respectively connected to the input end of the regenerator, the output end of the regenerator is connected to the air inlet end of the high-temperature heater, the regenerator is connected to the waste heat boiler, the return air end of the high-temperature heater is connected to the gas input end of the turbine, and the power output end of the turbine is connected to a load.

[0009] Preferably, three groups of the circulating heating components are provided, and three groups of the storage tanks and the heat exchange tubes are provided. Each group of the circulating heating components is coordinated with each corresponding group of the storage tanks and each group of the heat exchange tubes. The three groups of circulating heating components are connected in parallel to the cogeneration component, and the three groups of storage tanks are respectively filled with copper heat storage bodies, aluminum heat storage bodies, and zinc heat storage bodies.

[0010] Preferably, a feed pipe and a maintenance pipe are provided on the top of the storage tank, a feed valve is provided on the feed pipe, a discharge pipe is provided on the bottom of the storage tank, a discharge valve is provided on the discharge pipe, and the feed pipe, maintenance pipe and discharge pipe are all connected to the inner cavity of the storage tank.

[0011] Furthermore, an outer shell is provided on the outer side of the storage tank, a heat-insulating cavity is formed between the outer shell and the storage tank, and a heat-insulating layer is provided in the heat-insulating cavity.

[0012] Compared with the prior art, the advantages of the present invention are:

[0013] Copper, aluminum and zinc heat storage bodies are used as phase change heat storage materials in the storage tank. By utilizing latent heat and sensible heat at the same time, a higher heat storage density can be obtained, which can significantly improve the energy conversion efficiency and economy. In combination with low-melting-point metals such as sodium and tin as heat carriers, a heat and power cogeneration system based on metal high-temperature phase change heat storage is proposed. The metal as the heat storage material is basically not consumed, and heat is transferred between the heat storage material and the power cycle working fluid. Metal is used as a phase change material, and the latent heat of the phase change of the metal at high temperature is utilized to store heat. At the same time, due to their good thermal conductivity, their sensible heat can also be utilized. Compared with the current molten salt heat storage, more heat energy can be stored in the same space, and the heat transfer efficiency is much higher than the traditional one. A combined cycle of gas power cycle and steam power cycle is adopted, and the conversion efficiency is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the overall structure of the combined heat and power storage system based on high-temperature metal phase change heat storage of the present invention;

[0015] Figure 2 This is a schematic diagram of the structure when two sets of circulating heating components are installed;

[0016] Figure 3 This is a schematic diagram of the structure when installing a single set of circulation heating components.

[0017] Description of the numbers in the figure:

[0018] 1. Phase change heat storage material; 2. Storage tank; 3. Heat exchange tube; 4. Heat carrier; 5. Circulating heating component; 501. Low-temperature heater; 502. First delivery pump; 503. Second delivery pump; 504. High-temperature heater; 505. First three-way valve; 506. Second three-way valve; 6. Cogeneration component; 601. Compressor; 602. Turbine; 603. Regenerator; 7. Waste heat boiler; 8. Load; 201. Feed pipe; 202. Maintenance pipe; 203. Feed valve; 204. Discharge pipe; 205. Discharge valve; 9. Casing; 10. Insulation layer. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] Example 1:

[0021] See also Figures 1 to 3The combined heat and power storage system based on high-temperature metal phase change heat storage includes a storage tank 2 for storing phase change heat storage material 1, a heat exchange tube 3 arranged in the storage tank 2, and a circulating heating component 5 for circulating heating a heat carrier 4. The phase change heat storage material 1 is selected from one or more of copper heat storage body, aluminum heat storage body, and zinc heat storage body. The heat carrier 4 is selected from one of metal sodium and metal tin.

[0022] The circulating heating assembly 5 includes a low-temperature heater 501 for preliminarily heating the heat carrier 4, a first delivery pump 502 and a second delivery pump 503 for delivering the heat carrier 4, a high-temperature heater 504 for finally heating the heat carrier 4, a first three-way valve 505, and a second three-way valve 506. One end of the heat exchange pipe 3 passes through the storage tank 2 and is connected to the first end of the first three-way valve 505, and the other end of the heat exchange pipe 3 passes through the storage tank 2 and is connected to the first end of the second three-way valve 506. The second end of the first three-way valve 505 is connected to the first delivery pump 50 2, the input end of the first delivery pump 502 is connected to the output end of the low-temperature heater 501, the input end of the low-temperature heater 501 is connected to the second end of the second three-way valve 506, the third end of the second three-way valve 506 is connected to the output end of the second delivery pump 503, the input end of the second delivery pump 503 is connected to the output end of the high-temperature heater 504, and the input end of the high-temperature heater 504 is connected to the third end of the first three-way valve 505; in addition, a cogeneration component 6 is also provided on the high-temperature heater 504.

[0023] The cogeneration component 6 includes a compressor 601, a turbine 602, and a regenerator 603. The gas output terminals of the compressor 601 and the turbine 602 are respectively connected to the input terminal of the regenerator 603. The output terminal of the regenerator 603 is connected to the air inlet terminal of the high-temperature heater 504. The regenerator 603 is connected to the waste heat boiler 7. The return air terminal of the high-temperature heater 504 is connected to the gas input terminal of the turbine 602. The power output terminal of the turbine 602 is connected to the load 8.

[0024] S1: According to actual needs, one set of circulating heating components 5 can be selected to be used in conjunction with the storage tank 2 and the heat exchange tube 3 to be connected to the cogeneration component 6. Of course, multiple sets of circulating heating components 5 and storage tanks 2 can also be used in parallel according to usage requirements;

[0025] S2: During heat storage operation, the heat carrier 4 is discharged from the low-temperature heater 501 and driven by the first delivery pump 502. It enters the channel of the heat exchange tube 3 through the first end of the first three-way valve 505, heats the heat storage body in the storage tank 2, and then returns to the low-temperature heater 501 through the first and second ends of the second three-way valve 506 for heating.

[0026] S3: During cogeneration operation, the compressed air discharged from the compressor 601 enters the regenerator 603 and exchanges heat with the high-temperature air discharged from the turbine 602 in the regenerator 603 before entering the high-temperature heater 504. The heat carrier 4 is driven by the second delivery pump 503, enters the heat exchange pipe 3 through the third end of the second three-way valve 506, absorbs the latent heat and sensible heat of the heat storage body in the storage tank 2, and enters the high-temperature heater 504 through the third end of the first three-way valve 505. The heat carrier 4 exchanges heat with the compressed air here. After the compressed air is heated to a high temperature, it enters the turbine 602 to expand and perform work, driving the load 8. The air that has expanded and performed work in the turbine 602 first enters the regenerator 603 to preheat the compressed air discharged from the compressor 601, and then enters the waste heat boiler 7 to generate steam. The steam can further expand and perform work in the externally connected steam turbine, and after being reduced to an appropriate pressure, it enters the steam pipeline network for heat supply, thereby achieving energy storage, utilizing cogeneration, and improving energy conversion efficiency.

[0027] Copper heat storage body, aluminum heat storage body and zinc heat storage body are used as phase change heat storage material 1 in the storage tank 2. The energy storage density is high, which can significantly improve the efficiency and economy of energy conversion. In combination with metallic sodium and tin low melting point metals as heat carriers 4, a heat and power cogeneration system based on metal high temperature phase change heat storage is proposed. Heat is transferred between the heat storage material and the power cycle working fluid. The heat transfer efficiency is much higher than the traditional one. A combined cycle of gas power cycle and steam power cycle is adopted, and the conversion efficiency is high.

[0028] Example 2:

[0029] On the basis of Example 1, three groups of circulating heating components 5 are provided, and three groups of storage tanks 2 and heat exchange tubes 3 are provided. Each group of circulating heating components 5 is provided in conjunction with each corresponding group of storage tanks 2 and each group of heat exchange tubes 3. The three groups of circulating heating components 5 are connected in parallel to the cogeneration component 6. The three groups of storage tanks 2 are respectively filled with copper heat storage body, aluminum heat storage body, and zinc heat storage body;

[0030] S1: According to actual needs, one set of circulating heating components 5 can be selected to be used in conjunction with the storage tank 2 and the heat exchange tube 3 to be connected to the cogeneration component 6. Of course, multiple sets of circulating heating components 5 and storage tanks 2 can also be used in parallel according to usage requirements, which is flexible.

[0031] S2: During heat storage operation, the heat carrier 4 is discharged from the low-temperature heater 501 and driven by the first delivery pump 502. It enters the channel of the heat exchange tube 3 through the first end of the first three-way valve 505, heats the heat storage body in the storage tank 2, and then returns to the low-temperature heater 501 through the first and second ends of the second three-way valve 506 for heating.

[0032] S3: During cogeneration operation, the compressed air discharged from the compressor 601 enters the regenerator 603 and exchanges heat with the high-temperature air discharged from the turbine 602 in the regenerator 603 before entering the high-temperature heater 504. The heat carrier 4 is driven by the second delivery pump 503, enters the heat exchange pipe 3 through the third end of the second three-way valve 506, absorbs the latent heat and sensible heat of the heat storage body in the storage tank 2, and enters the high-temperature heater 504 through the third end of the first three-way valve 505. The heat carrier 4 exchanges heat with the compressed air here. After the compressed air is heated to a high temperature, it enters the turbine 602 to expand and perform work, driving the load 8. The air that has expanded and performed work in the turbine 602 first enters the regenerator 603 to preheat the compressed air discharged from the compressor 601, and then enters the waste heat boiler 7 to generate steam. The steam can further expand and perform work in the externally connected steam turbine, and after being reduced to an appropriate pressure, it enters the steam pipeline network for heat supply, thereby achieving energy storage, utilizing cogeneration, and improving energy conversion efficiency.

[0033] Copper, aluminum, and zinc heat storage bodies are used in the storage tank 2 as phase change heat storage materials 1, which have high energy storage density and can significantly improve the efficiency and economy of energy conversion. In addition, low-melting-point metals such as sodium and tin are used as heat carriers 4. A heat and power cogeneration system based on metal high-temperature phase change heat storage is proposed. Heat is transferred between the heat storage material and the power cycle working fluid. The heat transfer efficiency is much higher than that of traditional systems. A combined cycle of gas power cycle and steam power cycle is used, resulting in high conversion efficiency.

[0034] In this embodiment, a feed pipe 201 and a maintenance pipe 202 are provided at the top of the storage tank 2, a feed valve 203 is provided on the feed pipe 201, a discharge pipe 204 is provided at the bottom of the storage tank 2, and a discharge valve 205 is provided on the discharge pipe 204. The feed pipe 201, the maintenance pipe 202 and the discharge pipe 204 are all connected to the inner cavity of the storage tank 2; the injection and discharge of the heat storage body are completed by using the feed pipe 201 and the discharge pipe 204;

[0035] In this embodiment, an outer shell 9 is provided on the outside of the storage tank 2, and an insulation cavity is formed between the outer shell 9 and the storage tank 2. An insulation layer 10 is provided in the insulation cavity. The insulation layer 10 is used to reduce the heat dissipation of the storage tank 2 to the surrounding environment, thereby saving energy.

[0036] The working process of the present invention is as follows:

[0037] S1: According to actual needs, one set of circulating heating components 5 can be selected to be used in conjunction with the storage tank 2 and the heat exchange tube 3 to be connected to the cogeneration component 6. Of course, multiple sets of circulating heating components 5 and storage tanks 2 can also be used in parallel according to usage requirements;

[0038] S2: During heat storage operation, the heat carrier 4 is discharged from the low-temperature heater 501 and driven by the first delivery pump 502. It enters the channel of the heat exchange tube 3 through the first end of the first three-way valve 505, heats the heat storage body in the storage tank 2, and then returns to the low-temperature heater 501 through the first and second ends of the second three-way valve 506 for heating.

[0039] S3: During cogeneration operation, the compressed air discharged from the compressor 601 enters the regenerator 603 and exchanges heat with the high-temperature air discharged from the turbine 602 in the regenerator 603 before entering the high-temperature heater 504. The heat carrier 4 is driven by the second delivery pump 503, enters the heat exchange pipe 3 through the third end of the second three-way valve 506, absorbs the latent heat and sensible heat of the heat storage body in the storage tank 2, and enters the high-temperature heater 504 through the third end of the first three-way valve 505. The heat carrier 4 exchanges heat with the compressed air here. After the compressed air is heated to a high temperature, it enters the turbine 602 to expand and perform work, driving the load 8. The air that has expanded and performed work in the turbine 602 first enters the regenerator 603 to preheat the compressed air discharged from the compressor 601, and then enters the waste heat boiler 7 to generate steam. The steam can further expand and perform work in the externally connected steam turbine, and after being reduced to an appropriate pressure, it enters the steam pipeline network for heat supply, thereby achieving energy storage, utilizing cogeneration, and improving energy conversion efficiency.

[0040] Copper heat storage body, aluminum heat storage body and zinc heat storage body are used as phase change heat storage material 1 in the storage tank 2. The energy storage density is high, which can significantly improve the efficiency and economy of energy conversion. In combination with metallic sodium and tin low melting point metals as heat carriers 4, a heat and power cogeneration system based on metal high temperature phase change heat storage is proposed. Heat is transferred between the heat storage material and the power cycle working fluid. The heat transfer efficiency is much higher than the traditional one. A combined cycle of gas power cycle and steam power cycle is adopted, and the conversion efficiency is high.

[0041] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any person skilled in the art who, within the technical scope disclosed by the present invention, makes equivalent substitutions or modifications based on the technical solutions and improved concepts of the present invention shall be covered by the scope of protection of the present invention.

Claims

1. A combined heat and power storage system based on high-temperature metal phase change heat storage, characterized by: The invention comprises a storage tank (2) for storing a phase-change heat storage material (1), a heat exchange tube (3) arranged in the storage tank (2), and a circulating heating component (5) for circulating heating a heat carrier (4), wherein the phase-change heat storage material (1) is selected from one or more of a copper heat storage body, an aluminum heat storage body, and a zinc heat storage body, and the heat carrier (4) is selected from one of metallic sodium and metallic tin; The circulating heating component (5) comprises a low-temperature heater (501) for preliminarily heating the heat carrier (4), a first delivery pump (502) and a second delivery pump (503) for delivering the heat carrier (4), a high-temperature heater (504) for finally heating the heat carrier (4), a first three-way valve (505), and a second three-way valve (506). One end of the heat exchange pipe (3) passes through the storage tank (2) and is communicated with the first end of the first three-way valve (505). The other end of the heat exchange pipe (3) passes through the storage tank (2) and is communicated with the first end of the second three-way valve (506). The second end of the first three-way valve (505) is connected to the second three-way valve (506). The output end of a delivery pump (502) is connected, the input end of the first delivery pump (502) is connected to the output end of the low-temperature heater (501), the input end of the low-temperature heater (501) is connected to the second end of the second three-way valve (506), the third end of the second three-way valve (506) is connected to the output end of the second delivery pump (503), the input end of the second delivery pump (503) is connected to the output end of the high-temperature heater (504), and the input end of the high-temperature heater (504) is connected to the third end of the first three-way valve (505); in addition, a cogeneration component (6) is also provided on the high-temperature heater (504); The cogeneration component (6) includes a compressor (601), a turbine (602), and a regenerator (603). The gas output end of the compressor (601) and the gas output end of the turbine (602) are respectively connected to the input end of the regenerator (603). The output end of the regenerator (603) is connected to the air inlet end of the high-temperature heater (504). The regenerator (603) is connected to a waste heat boiler (7). The return air end of the high-temperature heater (504) is connected to the gas input end of the turbine (602). The power output end of the turbine (602) is connected to a load (8).

2. The combined heat and power storage system based on high-temperature metal phase change heat storage according to claim 1 is characterized in that: The circulating heating components (5) are provided in three groups, and the storage tanks (2) and the heat exchange tubes (3) are provided in three groups. Each group of the circulating heating components (5) is provided in conjunction with each corresponding group of the storage tanks (2) and each corresponding group of the heat exchange tubes (3). The three groups of circulating heating components (5) are connected in parallel to the cogeneration component (6). The three groups of the storage tanks (2) are filled with a copper heat storage body, an aluminum heat storage body, and a zinc heat storage body, respectively.

3. The combined heat and power storage system based on high-temperature metal phase change heat storage according to claim 1 is characterized in that: A feed pipe (201) and a maintenance pipe (202) are provided at the top of the storage tank (2); a feed valve (203) is provided on the feed pipe (201); a discharge pipe (204) is provided at the bottom of the storage tank (2); a discharge valve (205) is provided on the discharge pipe (204); the feed pipe (201), the maintenance pipe (202) and the discharge pipe (204) are all in communication with the inner cavity of the storage tank (2).

4. The combined heat and power storage system based on high-temperature metal phase change heat storage according to claim 1 is characterized in that: An outer shell (9) is provided on the outside of the storage tank (2), a heat preservation cavity is formed between the outer shell (9) and the storage tank (2), and a heat preservation layer (10) is provided in the heat preservation cavity.

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