High-temperature heat storage system composed of multiple layers of different materials and method of high-temperature heat storage system

Abstract

The invention provides a high-temperature heat storage system composed of multiple layers of different materials and a method thereof.According to the system, the interior of a heat storage tank is divided into a first heat storage layer, a second heat storage layer and a third heat storage layer, and the heat storage layers are formed by stacking different heat storage media; and heat can be more uniformly distributed in the heat storage tank due to the heat conduction performance difference between different materials, so that the formation of a thermocline in the heat storage tank is inhibited. Meanwhile, heat transfer among different layers is hindered due to material differences, so that the forming speed of the thermocline is slowed down, and the thickness of the thermocline is reduced. And by inhibiting the thermocline phenomenon, the efficiency of the heat storage system can be remarkably improved, the loss is less in the storage and release process, and the economic benefit of the heat storage system is improved.

Description

Technical Field

[0001] The present application relates to the field of thermal energy storage technology, and in particular to a high-temperature heat storage system composed of multiple layers of different materials and a method thereof. Background Art

[0002] With the acceleration of the global energy transition, thermal energy storage technology is attracting increasing attention due to its key role in energy time regulation and improving energy efficiency. In particular, in areas such as industrial waste heat utilization, building heating and cooling, and solar thermal power generation, thermal energy storage technology is considered an important means to improve system thermal efficiency and reduce energy waste. However, existing thermal energy storage technologies still face numerous challenges in practical application, among which the thermocline phenomenon is one of the main factors affecting the efficiency of thermal energy storage systems.

[0003] Current solutions focus on optimizing energy storage materials, but due to the complexity of the thermocline phenomenon, existing methods have limited effectiveness in suppressing its formation. The thermocline problem is particularly prominent in large-scale energy storage systems, becoming a limiting factor in further improving system efficiency and economics. Summary of the Invention

[0004] To address the above-mentioned issues, the present application provides a high-temperature heat storage system and method comprising multiple layers of different materials. This system divides the interior of a heat storage tank into a first, second, and third heat storage layer, each composed of a stack of different heat storage media. The differences in thermal conductivity between the different materials distribute heat more evenly within the tank, thereby suppressing the formation of a thermocline layer within the tank. Furthermore, the material differences hinder heat transfer between the different layers, slowing the formation of the thermocline layer and reducing its thickness. By suppressing the formation of the thermocline layer, the efficiency of the heat storage system can be significantly improved, resulting in less loss during storage and release, and increasing the economic benefits of the heat storage system.

[0005] In a first aspect, the present application provides a high-temperature heat storage system composed of multiple layers of different materials, the system comprising a heat storage tank (1); The heat storage tank (1) is provided with a first opening (11) and a second opening (12) at two opposite ends along a first direction, respectively, and the first opening (11) is located above the second opening (12); The interior of the heat storage tank (1) is divided into a first heat storage layer (13), a second heat storage layer (14), and a third heat storage layer (15); the first opening (11) is connected to the interior of the first heat storage layer (13); and the second opening (12) is connected to the interior of the third heat storage layer (15); The first heat storage layer (13) is composed of a stacked first heat storage medium, the second heat storage layer (14) is composed of a stacked second heat storage medium, and the third heat storage layer (15) is composed of a stacked third heat storage medium.

[0006] Furthermore, the second heat storage layer (14) occupies 50% to 90% of the total internal volume of the heat storage tank (1).

[0007] Furthermore, the second heat storage layer (14) accounts for 65% to 80% of the total internal volume of the heat storage tank (1).

[0008] Furthermore, the volume ratio of the first heat storage layer (13) to the third heat storage layer (15) in the heat storage tank (1) is (0.5-1):1.

[0009] Furthermore, in the heat storage tank (1), a first cavity (16) is provided between the first heat storage layer (13) and the first opening (11); A second cavity (17) is provided between the third heat storage layer (15) and the second opening (12).

[0010] Furthermore, the dimensions of the first end (18) and the second end (19) of the heat storage tank (1) in the first direction gradually decrease; The dimensions of the first end (18) and the second end (19) on the side close to the second heat storage layer (14) are larger than the dimensions on the side away from the second heat storage layer.

[0011] Furthermore, the system further comprises a plurality of suppression plates (2), each of which is provided with a through hole (21); The plurality of suppression plates (2) are respectively arranged between the first heat storage layer (13) and the second heat storage layer (14), between the second heat storage layer (14) and the third heat storage layer (15), and between the third heat storage layer (15) and the second opening (12).

[0012] Furthermore, the size of the suppression plate (2) in the first direction is 0.1 m to 1 m.

[0013] In a second aspect, the present application provides a high-temperature heat storage method composed of multiple layers of different materials, the method being applicable to the high-temperature heat storage system composed of multiple layers of different materials described in the first aspect above, the method comprising: A heat storage fluid with a temperature of 500° C. to 2000° C. is fed into the heat storage tank (1) along the first opening (11); the heat storage fluid exchanges heat with the first heat storage medium after reaching the first heat storage layer (13); After the heat storage fluid undergoes the primary heat exchange, it reaches the second heat storage layer (14) along the first direction and then undergoes secondary heat exchange with the second heat storage medium; After the heat storage fluid undergoes secondary heat exchange, it reaches the third heat storage layer (15) along the first direction and undergoes a third heat exchange with the third heat storage medium; The heat storage fluid after the three heat exchanges is discharged from the heat storage tank (1) along the first direction from the second opening (12) to complete heat storage; Wherein, the heat storage fluid is any one of molten salt, thermal oil, quartz sand, air, nitrogen and argon; The first heat storage medium is any one of cast iron, stainless steel, alumina, magnesia, zirconia and phase change material with a particle size of less than 2 cm; The second heat storage medium is any one of sand, quartz, cement, concrete and graphite with a particle size of less than 2 cm; The third heat storage medium is any one of cast iron, stainless steel, aluminum oxide, magnesium oxide, zirconium oxide and phase change material with a particle size of less than 2 cm; Furthermore, the first heat storage medium and the third heat storage medium are phase change materials; The phase change material is composed of a metal element wrapped in a particle coating; Wherein, the particle coating is a hollow particle composed of any one of aluminum silicate, calcium silicate, polyimide, aluminum oxide and zirconium oxide; The metal element is any one of iron, aluminum, tin, magnesium and copper.

[0014] In summary, this application includes at least one of the following beneficial technical effects: 1. The present application provides a high-temperature heat storage system composed of multiple layers of different materials, the system comprising a heat storage tank having a first opening and a second opening respectively formed at opposite ends along a first direction. The interior of the heat storage tank is divided into a first heat storage layer, a second heat storage layer, and a third heat storage layer. The first heat storage layer is composed of a stacked first heat storage medium, the second heat storage layer is composed of a stacked second heat storage medium, and the third heat storage layer is composed of a stacked third heat storage medium. During implementation, because the heat storage layers are composed of different heat storage media, the difference in thermal conductivity between the different materials inhibits heat diffusion, thereby inhibiting the formation of a thermocline layer within the heat storage tank. At the same time, heat transfer between the different layers is hindered due to material differences, which can slow the formation of the thermocline layer. By inhibiting the formation of the thermocline layer, the efficiency of the heat storage system can be further improved, with less loss during storage and release, thereby improving the economic benefits of the heat storage system. 2. A high-temperature heat storage method composed of multiple layers of different materials. The system used in this method includes a first heat storage layer, a second heat storage layer, and a third heat storage layer, and each layer is composed of a different heat storage material, which can more effectively disperse and store thermal energy. In the method provided in this application, the different materials selected have different thermal conductivities and heat capacities, which helps to reduce the accumulation of heat energy in the same layer, thereby suppressing the formation of a thermocline layer. By setting up a three-stage heat exchange, the heat storage fluid is exchanged layer by layer in the heat storage tank, and the heat energy is gradually released and stored in each layer of the medium, achieving uniform distribution of heat energy and further suppressing the formation of a thermocline layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 A schematic structural diagram of a high-temperature heat storage system composed of multiple layers of different materials proposed in an embodiment of the present application is shown; Figure 2 A schematic structural diagram of the suppression plate proposed in an embodiment of the present application is shown; Figure 3 A flow chart of a high-temperature heat storage method comprising multiple layers of different materials proposed in an embodiment of the present application is shown; Figure 4 A flow chart of a heat release method for a high-temperature heat storage system composed of multiple layers of different materials proposed in an embodiment of the present application is shown.

[0017] Description of reference numerals: 1. Heat storage tank; 11. First opening; 12. Second opening; 13. First heat storage layer; 14. Second heat storage layer; 15. Third heat storage layer; 16. First cavity; 17. Second cavity; 18. First end; 19. Second end; 2. Suppression plate; 21. Through hole. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0019] In the drawings, the sizes of components, layer thicknesses, or regions may be exaggerated for clarity. Therefore, any implementation of the present disclosure is not necessarily limited to the dimensions shown in the drawings, and the shapes and sizes of components in the drawings do not reflect true proportions. Furthermore, the drawings schematically illustrate idealized examples, and any implementation of the present disclosure is not limited to the shapes or values ​​shown in the drawings.

[0020] Among related technologies, thermal energy storage is gaining increasing attention as the global energy transition accelerates, due to its key role in regulating energy time and improving energy efficiency. In particular, in areas such as industrial waste heat utilization, building heating and cooling, and solar thermal power generation, thermal energy storage is considered an important means of improving system thermal efficiency and reducing energy waste.

[0021] Thermal energy storage technology involves converting thermal energy into other forms of energy through certain technical means, storing them, and then converting them back into thermal energy for use when needed. Its principles primarily involve the first and second laws of thermodynamics, exploiting the properties of matter, such as temperature differences, phase transitions, or chemical reactions, to store and release thermal energy.

[0022] However, existing thermal energy storage technologies still face many challenges in practical applications, among which the thermocline phenomenon is one of the main factors affecting the efficiency of thermal energy storage systems.

[0023] The thermocline layer, also known as the "temperature jump layer" or "temperature gradient layer," is an interface layer formed by uneven temperature gradient distribution within the system in a thermal energy storage system. It is characterized by non-ideal stratification of heat transfer within the storage medium. This interface layer separates two or more fluids with significantly different temperatures. The main characteristics of the thermocline layer include: 1. The thermocline is an area where the temperature changes rapidly and the temperature gradient is large, that is, the temperature changes significantly over a very short distance; 2. It acts as an interface, separating fluids of different temperatures. This separation helps maintain the thermal efficiency of the system, but it may also lead to uneven heat distribution.

[0024] The formation of a thermocline prevents the efficient use of heat during storage and release. Heat tends to flow from high-temperature to low-temperature regions, and the presence of a thermocline hinders this transfer, preventing some heat from being effectively stored or released. This increases heat loss and reduces energy storage efficiency. Furthermore, the presence of a thermocline can lead to operational instability in the system, impacting the long-term performance of energy storage equipment.

[0025] Current technical solutions focus on optimizing energy storage materials, but due to the complexity of the thermocline phenomenon, existing methods have limited effectiveness in suppressing its formation. The thermocline problem is particularly prominent in large-scale energy storage systems, becoming a constraint on further improving system efficiency and economics.

[0026] To address the problems existing in the related art, the embodiments of the present application provide a high-temperature heat storage system and method composed of multiple layers of different materials. By providing a layered structure within a heat storage tank, with each layer being composed of a different heat storage medium, the temperature distribution within the heat storage tank is made more uniform by utilizing the differences in thermal conductivity of different heat storage media, thereby suppressing the formation of a thermocline layer and reducing the impact of the thermocline layer on the mass transfer efficiency and energy storage effect within the heat storage tank.

[0027] For specific implementation, see Figure 1 , the system includes a heat storage tank 1; The heat storage tank 1 is provided with a first opening 11 and a second opening 12 at two opposite ends along a first direction, respectively. The first opening 11 is located above the second opening 12. The interior of the heat storage tank 1 is divided into a first heat storage layer 13, a second heat storage layer 14 and a third heat storage layer 15. The first opening 11 is connected to the interior of the first heat storage layer 13, and the second opening 12 is connected to the interior of the third heat storage layer 15. The first heat storage layer 13 is composed of a stacked first heat storage medium, the second heat storage layer 14 is composed of a stacked second heat storage medium, and the third heat storage layer 15 is composed of a stacked third heat storage medium.

[0028] It should be noted that the heat storage tank 1 is a sealed tank that is resistant to high temperatures and corrosion; The cross section of the heat storage tank 1 can be circular, square, diamond or oval, etc. The first direction x is the direction extending along the length of the heat storage tank 1; The shapes of the first heat storage layer 13, the second heat storage layer 14 and the third heat storage layer 15 are adapted to the shape of the heat storage tank 1; In specific implementation, a first heat storage medium is stacked and placed within the heat storage tank 1, forming a first heat storage layer 13 within the heat storage tank 1. A second heat storage medium is stacked and placed below the first heat storage layer 13 to form a second heat storage layer 14 within the heat storage tank 1. A third heat storage medium is stacked and placed below the second heat storage layer 14 to form a third heat storage layer 15 within the heat storage tank 1. The heat storage fluid flows downward through the first opening 11 into the heat storage tank 1, first reaching the first heat storage layer 13. As the heat storage fluid gradually flows downward, it exchanges heat with the first heat storage medium, storing some heat in the first heat storage medium. When the heat storage fluid reaches the second heat storage layer 14, it continues to exchange heat with the second heat storage medium, storing more heat in the second heat storage medium. When the heat storage fluid reaches the third heat storage layer 15, it exchanges heat with the third heat storage medium, storing the remaining heat in the third heat storage medium, completing the heat storage process.

[0029] The embodiment of the present application utilizes a layered design within the heat storage tank 1, utilizing materials with varying thermal properties (e.g., specific heat capacity and thermal conductivity) to optimize the heat storage and release performance of each layer. Selecting different materials as the heat storage medium allows for different parameters, such as heat capacity and thermal conductivity, within each layer. This results in a more uniform heat distribution along the first direction within the heat storage tank 1, thereby helping to suppress the formation of a thermocline layer. Due to the differences in thermal properties between the different materials, heat transfer between layers is hindered, slowing the formation of the thermocline layer. By suppressing the thermocline layer phenomenon, the efficiency of the thermal energy storage system can be improved. The more uniform heat distribution achieved by the layered structure within the heat storage tank 1 also reduces heat loss during storage and release, helping to improve the overall efficiency of the heat storage system and enhance energy efficiency.

[0030] The first opening 11 and the second opening 12 are connected to the interior of the first heat storage layer 13 and the third heat storage layer 15 respectively, and the first opening 11 is located above the second opening 12, so that heat can be transferred more flexibly between different heat storage layers along the first direction, further reducing the impact of the thermocline layer on the mass transfer efficiency.

[0031] The present embodiment utilizes a layered design within the heat storage tank 1 and employs a combination of different materials, enabling the system to adapt to a variety of application scenarios and load requirements. During implementation, the material ratios and number of layers can be adjusted to further optimize system performance and cost. This system provides new insights and approaches to thermal energy storage technology, helping to promote continued development and innovation in this field.

[0032] In specific implementation, when the system provided in the embodiment of the present application is used for heat release treatment, the cold fluid is fed upward into the heat storage tank 1 along the second opening 12, and the cold fluid passes upward through the third heat storage layer 15, the second heat storage layer 14 and the first heat storage layer 13 in sequence, and exchanges heat with the third heat storage medium, the second heat storage medium and the first heat storage medium to achieve heat release.

[0033] In a specific implementation, the first heat storage medium is any one of cast iron, stainless steel, aluminum oxide, magnesium oxide, zirconium oxide and phase change material with a particle size of less than 2 cm; The second heat storage medium is any one of sand, quartz, cement, concrete and graphite with a particle size of less than 2 cm; The third heat storage medium is any one of cast iron, stainless steel, alumina, magnesia, zirconia and phase change material with a molten particle size of less than 2 cm; The first heat storage medium selected in the embodiments of the present application has a higher density and specific heat capacity, and a lower thermal conductivity, which is more helpful in suppressing the expansion of the thermocline layer during the heat release process.

[0034] Compared with the first heat storage medium, the second heat storage medium has a smaller density and specific heat capacity, as well as a lower thermal conductivity, which is more conducive to the second heat storage layer 14 absorbing heat quickly and expanding rapidly to form a high-temperature area.

[0035] Compared with the second heat storage medium, the third heat storage medium has a larger density and specific heat capacity, and a lower thermal conductivity, which is more conducive to suppressing the formation of the third heat storage layer 15 and the thermocline layer at the second opening 12, and in particular can reduce the thickness of the thermocline layer at the second opening 12.

[0036] In some embodiments, see Figure 1 The second heat storage layer 14 accounts for 50% to 90% of the total internal volume of the heat storage tank 1.

[0037] It should be noted that the volume of the second heat storage layer 14 is the total volume of the stacked heat storage media.

[0038] In specific implementation, by configuring the second heat storage layer 14 to occupy 50% to 90% of the total internal volume of the heat storage tank 1, the second heat storage layer 14 has the largest volume compared to the first and third storage layers. A large amount of heat energy from the heat storage fluid is stored and dispersed in this layer. Furthermore, by configuring the second heat storage layer 14 to be made of a material different from that of the first and third heat storage layers 13 and 15, the heat energy from the heat storage fluid can be more effectively absorbed and dispersed, reducing heat accumulation within the same layer and achieving uniform distribution of heat energy within the second heat storage medium. This reduces the amount of heat energy diffusing to the third heat storage layer 15, extending the high-temperature zone within the heat storage tank 1, further suppressing the formation of a thermocline layer, and reducing the thickness of the thermocline layer at the second opening 12. This suppression of the thermocline layer also helps enhance system stability. Due to the more uniform distribution of heat energy, temperature fluctuations in the system are reduced, thereby improving system reliability and durability.

[0039] In some embodiments, see Figure 1 The second heat storage layer 14 accounts for 65% to 80% of the total internal volume of the heat storage tank 1.

[0040] In practice, by optimizing the second heat storage layer 14 to occupy the total volume of the heat storage tank 1, the high-temperature region within the heat storage tank 1 can be more appropriately positioned, ensuring that more heat storage medium is kept at a higher temperature, thereby improving the thermal efficiency of the entire system. This also helps reduce heat loss, as heat energy in the high-temperature region is less likely to be dissipated into the environment through heat conduction or convection.

[0041] In some embodiments, see Figure 1 The volume ratio of the first heat storage layer 13 to the third heat storage layer 15 inside the heat storage tank 1 is (0.5~1):1.

[0042] In a specific implementation, the volume ratio of the first heat storage layer 13 to the third heat storage layer 15 in the heat storage tank 1 can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1 or 1:1.

[0043] By adjusting the volume ratio of the first heat storage layer 13 to the third heat storage layer 15, the temperature distribution within the heat storage tank 1 can be more effectively controlled. Simultaneously, these two layers act as a "buffer zone" for thermal energy, inhibiting its diffusion toward the first opening 11 and the second opening 12 of the heat storage tank 1. By rationally optimizing the volumes of the first and second heat storage layers 13, 14, the temperature gradient within the heat storage tank 1 is reduced, thereby suppressing the formation of a thermocline layer at the first and second openings 11, 12. This allows more thermal energy to be effectively stored in the first and second heat storage media, and released for system use when needed, thereby improving thermal energy utilization and reducing energy waste.

[0044] In a specific implementation, it is further preferred that the first heat storage layer 13 accounts for 10% of the total volume of the heat storage tank 1, the second heat storage layer 14 accounts for 70% of the total volume of the heat storage tank 1, and the third heat storage layer 15 accounts for 10% of the total volume of the heat storage tank 1.

[0045] In some embodiments, see Figure 1 , in the heat storage tank 1 , a first cavity 16 is provided between the first heat storage layer 13 and the first opening 11 ; A second cavity 17 is provided between the third heat storage layer 15 and the second opening 12 .

[0046] It should be noted that the first cavity 16 accounts for 5% of the total volume of the heat storage tank 1, and the second cavity 17 accounts for the same amount of the total volume of the heat storage tank 1 as the first cavity 16.

[0047] By providing the first cavity 16 and the second cavity 17, two temperature buffer zones are added to the first opening 11 and the second opening 12 of the heat storage tank 1. When the heat storage fluid enters the heat storage tank 1 through the first opening 11, the first cavity 16 absorbs and disperses some of the heat energy, slowing the direct impact of the heat storage fluid on the first heat storage layer 13, thereby reducing the rate of temperature gradient formation. When the heat storage fluid completes heat storage and flows out of the third heat storage layer 15, the second cavity 17 serves as another temperature buffer zone, further reducing the diffusion of heat energy to the exterior of the heat storage tank 1. This maintains temperature uniformity within the heat storage tank 1, mitigates temperature fluctuations within the system, and reduces the thickness of the thermocline layer at the opening of the heat storage tank 1. Furthermore, a stable temperature environment helps extend the service life of the heat storage medium and system, reducing malfunctions and damage caused by temperature fluctuations.

[0048] In some embodiments, see Figure 1 , the sizes of the first end 18 and the second end 19 of the heat storage tank 1 in the first direction gradually decrease; The dimensions of the first end 18 and the second end 19 close to the second heat storage layer 14 are larger than the dimensions of the first end 18 and the second end 19 away from the second heat storage layer.

[0049] It should be noted that the first end 18 of the heat storage tank 1 is an end where the first cavity 16 is provided, and the second end 19 is an end where the second cavity 17 is provided; The dimensions of the first end 18 and the second end 19 of the heat storage tank 1 gradually decrease in the first direction, so that the shapes of the first cavity 16 and the second cavity 17 are trapezoidal; The dimensions of the first end 18 and the second end 19 close to the second heat storage layer 14 are expressed as: the dimensions of the connection between the first end 18 and the second end 19 of the heat storage tank 1 and the middle part of the heat storage tank 1; The dimensions of the first end 18 and the second end 19 away from the second reservoir are expressed as follows: the dimension of the first end 18 near the first opening 11 , and the dimension of the second end 19 near the second opening 12 ; The first end 18 of the heat storage tank 1 tapers upward along a first direction, and the second end 19 of the heat storage tank 1 tapers downward along the first direction.

[0050] In a specific implementation, by changing the dimensions of the first end 18 and the second end 19 of the heat storage tank 1, the fluid can flow more smoothly into and out of the heat storage tank 1, thereby reducing the turbulence or eddy current formed in the heat storage tank 1, thereby facilitating the suppression of the formation of a thermocline layer, reducing the ineffective diffusion of heat energy to both ends of the heat storage tank 1, and enabling more heat energy to be effectively stored in the heat storage medium.

[0051] Since the flow velocity of the fluid at both ends of the heat storage tank 1 can change gradually, the diffusion and mixing of heat energy caused by sudden velocity changes are avoided, which helps to maintain the uniformity of the temperature inside the heat storage tank 1, reduce the temperature gradient inside the heat storage tank 1, increase the mass transfer efficiency, and improve the storage efficiency of heat energy.

[0052] In some embodiments, see Figure 1 and Figure 2 , the system further comprises a plurality of suppression plates 2, each of which is provided with a through hole 21; The plurality of suppression plates 2 are respectively disposed between the first heat storage layer 13 and the second heat storage layer 14 , between the second heat storage layer 14 and the third heat storage layer 15 , and between the third heat storage layer 15 and the second opening 12 .

[0053] It should be noted that the shape of the suppression plate 2 is adapted to the shape of the heat storage tank 1; Both ends of the suppression plate 2 are fixed to the inner wall of the heat storage tank 1 along the horizontal direction.

[0054] By providing suppression plate 2, heat energy is transferred both through the heat storage medium and diffused through through-holes 21 on suppression plate 2, slowing the transfer of heat energy within heat storage tank 1. This prevents the formation of large temperature gradients during heat transfer, thereby suppressing the formation of a thermocline layer. Furthermore, by providing the suppression plate, the first, second, and third heat storage media are stacked and placed on suppression plate 2, reducing the movement of the heat storage medium in the first direction after being impacted by the fluid, thereby maintaining the stability of each heat storage layer within heat storage tank 1.

[0055] In a specific implementation, the diameter of the through hole 21 can be 5 mm to 100 mm, and the number of the through holes 21 can be 50 to 300.

[0056] In practice, if through-holes 21 are too large or too numerous, heat transfer will be too rapid, failing to effectively suppress the formation of a thermocline layer. If through-holes 21 are too small or too few, heat transfer efficiency will be compromised, reducing system performance. Therefore, selecting the appropriate diameter and number of through-holes 21 based on the size of the heat storage tank 1 and the fluid being transported is crucial for suppressing the thermocline layer and improving heat transfer efficiency.

[0057] In specific implementations, the material of the suppression plate 2 can be stainless steel, aluminum alloy, alumina ceramic, silicon nitride ceramic, carbon fiber composite material, glass fiber composite material, etc. The suppression plate 2 composed of these materials has good thermal conductivity and high temperature resistance, and can withstand long-term operation in high-temperature environments. It ensures that heat energy can be effectively transferred through the through-holes 21 and can withstand long-term operation in high-temperature environments. At the same time, the material must also have a certain strength and toughness to ensure that the suppression plate 2 will not be damaged by excessive force during use.

[0058] In some embodiments, see Figure 1 , the size of the suppression plate 2 in the first direction is 0.1 m~1 m.

[0059] It should be noted that the dimension of the suppression plate 2 in the first direction is: the vertical thickness of the suppression plate 2 in the first direction.

[0060] In practice, it is necessary to ensure that the suppression plate 2 effectively suppresses the formation of a thermocline layer while also preventing the suppression plate 2 from occupying too much space in the heat storage tank 1, thereby reducing the high-temperature area formed in the second heat storage layer 14. Reasonable limitations on the thickness of the suppression plate 2 also help reduce the size of the through hole 21 along the first direction, preventing the through hole 21 from being too deep, which would cause uneven temperature distribution on the suppression plate 2.

[0061] The present application also provides a high-temperature heat storage method composed of multiple layers of different materials, which is applicable to a high-temperature heat storage device composed of multiple layers of different materials, see Figure 3 , the method comprising: Step S1: feeding a heat storage fluid with a temperature of 500°C to 2000°C into the heat storage tank 1 through the first opening 11. After reaching the first heat storage layer 13, the heat storage fluid exchanges heat with the first heat storage medium. Step S2: After the heat storage fluid has undergone the primary heat exchange, it reaches the second heat storage layer 14 along the first direction and then undergoes secondary heat exchange with the second heat storage medium; Step S3: After the heat storage fluid undergoes secondary heat exchange, it reaches the third heat storage layer 15 along the first direction and undergoes a third heat exchange with the third heat storage medium; Step S4: the heat storage fluid after the three heat exchanges is discharged from the heat storage tank 1 from the second opening 12 along the first direction to complete heat storage; Wherein, the heat storage fluid is any one of molten salt, thermal oil, quartz sand, air, nitrogen and argon; The first heat storage medium is any one of cast iron, stainless steel, alumina, magnesia, zirconia and phase change material with a particle size of less than 2 cm; The second heat storage medium is any one of sand, quartz, cement, concrete and graphite with a particle size of less than 2 cm; The third heat storage medium is any one of molten salt with a particle size of less than 2 cm, heat transfer oil, quartz sand, air, nitrogen, argon and phase change material.

[0062] In practice, in a heat storage system, the heat storage fluid first enters the first layer of heat storage medium, exchanges heat with it, and transfers heat to the first heat storage medium. As the temperature of the heat storage fluid decreases, it continues to flow to the second heat storage medium, where it undergoes another heat exchange. This process continues until the heat storage fluid flows out of the third heat storage medium, at which point the heat storage fluid has transferred most of its heat to the second heat storage medium. Because the system proposed in this embodiment utilizes heat storage media composed of different materials in the first, second, and third heat storage layers 13, 14, and 15, each layer has different thermal properties (such as thermal conductivity and heat capacity) and responds differently to the heat of the heat storage fluid. This helps to create a more uniform temperature gradient during the heat storage process, effectively suppressing the formation of a thermocline layer. With fewer thermocline layers, the uniformity of the temperature distribution within the heat storage tank 1 is improved, helping to increase the thermal efficiency of the thermal energy storage system. The multi-layered heat storage medium structure allows more heat energy to be stored in the heat storage medium and released when needed.

[0063] In practice, molten salt and thermal oil have high thermal conductivity and heat capacity, while air, nitrogen, and argon have high thermal diffusivity, making them suitable for energy storage using the system provided in the embodiments of this application. Quartz sand has relatively low thermal conductivity but high heat capacity and stability, which can improve thermal storage efficiency.

[0064] The material selected for the first heat storage medium has a high melting point, high thermal stability and good thermal conductivity, and is suitable for directly exchanging heat with the input high-temperature heat storage fluid as the first heat storage layer 13, and can effectively absorb and store the heat of the high-temperature heat storage fluid.

[0065] The material selected for the second heat storage medium has low cost and moderate thermal conductivity, making it suitable as a second heat storage layer and capable of further stably storing more heat.

[0066] In a specific implementation, when the temperature of the heat storage fluid is lower than 1000°C, the heat storage fluid may be molten salt, thermal oil or air; When the temperature of the heat storage fluid is higher than 1000 °C, it is further determined whether the heat storage fluid will react with the heat storage medium. If so, nitrogen or argon is selected as the heat storage fluid.

[0067] In a specific implementation, the particle size of the first, second, and third heat storage media is all less than 2 cm, resulting in a large specific surface area. Because heat is stored not only within the heat storage medium but also at the interface between the heat storage medium and the heat storage fluid, the larger specific surface area of ​​the heat storage medium allows for greater heat storage.

[0068] In specific implementations, the first heat storage medium has excellent physical and chemical stability and does not react with the heat storage fluid. When the heat storage fluid is below 1000°C, the first heat storage medium can be cast iron or stainless steel; when the heat storage fluid is below 1500°C, the first heat storage medium can be aluminum oxide; and when the heat storage fluid is below 2000°C, the first heat storage medium can be magnesium oxide or zirconium oxide.

[0069] In practice, the second heat storage medium exhibits excellent physical and chemical stability and does not react with the heat storage fluid. For temperatures below 1000°C, the second heat storage medium can be sand, quartz, or cement; for temperatures below 1500°C, the second heat storage medium can be high-temperature concrete; and for temperatures below 2000°C, the second heat storage medium can be graphite.

[0070] In specific implementations, the third heat storage medium exhibits excellent physical and chemical stability and does not react with the heat storage fluid. For temperatures below 1000°C, cast iron or stainless steel can be used as the third heat storage medium; for temperatures below 1500°C, alumina can be used; and for temperatures below 2000°C, magnesium oxide or zirconium oxide can be used.

[0071] In some embodiments, the present application further provides a heat release method for a high-temperature heat storage system composed of multiple layers of different materials, specifically comprising: Step S11: A cold fluid with a temperature lower than 30°C is fed upward from the second opening 12 into the heat storage tank 1. After reaching the third heat storage layer 15, the cold fluid comes into contact with the third heat storage medium, and the third heat storage medium begins to release heat once. Step S12: After the first heat release, the cold fluid reaches the second heat storage layer 14 upwards and contacts the second heat storage medium, which then releases heat for the second time. Step S13: After the second heat release, the cold fluid reaches the first heat storage layer 13 and contacts the first heat storage medium. The first heat storage medium releases heat three times, and finally the fluid absorbs heat and is discharged from the heat storage tank 1 along the first opening 11. By providing a first heat storage layer 13, a second heat storage layer 14, and a third heat storage layer 15 in the system and using different heat storage media, the third heat storage medium can suppress the expansion of the thermocline layer during the heat release process, the second heat storage medium can ensure that the heat that cannot be extracted from the thermocline layer is taken away by the cold fluid as much as possible, and the first heat storage medium can further suppress the expansion of the exothermic thermocline layer, thereby improving the heat storage efficiency and energy density.

[0072] In some embodiments, the first heat storage medium and the third heat storage medium are phase change materials; The phase change material is composed of a metal element wrapped in a particle coating; Wherein, the particle coating is a hollow particle composed of any one of aluminum silicate, calcium silicate, polyimide, aluminum oxide and zirconium oxide; The metal element is any one of iron, aluminum, tin, magnesium and copper.

[0073] It should be noted that based on the characteristics of phase change materials, they will undergo phase change at a certain temperature, thereby being able to absorb or release a large amount of heat, which helps to regulate the temperature inside the heat storage system, reduce temperature gradients, and improve thermal efficiency.

[0074] In a specific implementation, the phase change material is composed of a particle coating and a metal element. When the metal element is heated and melted, it can be preserved in the particle coating to avoid contaminating the first heat storage medium or the third heat storage medium.

[0075] Among them, the particle coating is composed of high thermal conductivity materials such as aluminum silicate, calcium silicate, polyimide, aluminum oxide and zirconium oxide, which have good thermal conductivity; The metal element, serving as the core of the phase change material, not only increases the heat capacity of the first or third heat storage medium but also possesses excellent thermal conductivity and ductility, helping to evenly distribute heat within the first or third heat storage medium. Combined with a multi-layered heat storage medium design, this helps minimize the formation of thermocline layers.

[0076] In specific implementations, the heat storage fluid is below 1000°C, and the phase-change material exhibits phase-change heat, maintaining the temperature near its melting point. As the heat storage process nears completion, the third heat storage medium (i.e., the phase-change material) maintains a temperature near its melting point, suppressing the temperature of the second opening 12 and preventing the expansion of the thermocline layer. At the end of heat release, the temperature of the first opening 11 is maintained near its melting point by the first heat storage medium (i.e., the phase-change material), preventing the thermocline layer from expanding and thus reducing its thickness.

[0077] In order to enable those skilled in the art to understand the present application more clearly, the high-temperature heat storage system and method thereof composed of multiple layers of different materials described in the present application are now described in detail through the following embodiments.

[0078] Example 1 1. Argon gas at a temperature of 1000°C is transported downwardly through the first opening 11 into the heat storage tank 1, passes through the first cavity 16, reaches the first heat storage layer 13, and then exchanges heat with the alumina. 2. After the primary heat exchange, the argon gas passes through the through holes 21 on the suppression plate 2 in the first direction and reaches the second heat storage layer 14, where it undergoes secondary heat exchange with the concrete. 3. After the secondary heat exchange, the argon gas passes through the through holes 21 on the suppression plate 2 along the first direction and reaches the third heat storage layer 15, where it undergoes a third heat exchange with the alumina. 4. After three heat exchanges, the argon gas passes through the through hole 21 on the suppression plate 2 along the first direction, reaches the second cavity 17, and then is discharged from the heat storage tank 1 from the second opening 12, completing the heat storage process.

[0079] Example 2 1. The heat transfer oil at a temperature of 500°C is transported downwardly along the first opening 11 into the heat storage tank 1, passes through the first cavity 16, reaches the first heat storage layer 13, and then exchanges heat with the cast iron. 2. After the primary heat exchange, the heat transfer oil passes through the through holes 21 on the suppression plate 2 in the first direction and reaches the second heat storage layer 14, where it undergoes a secondary heat exchange with the sand and gravel. 3. After the secondary heat exchange, the heat transfer oil passes through the through hole 21 on the suppression plate 2 along the first direction and reaches the third heat storage layer 15, and then performs a third heat exchange with the cast iron; 4. After three heat exchanges, the heat transfer oil passes through the through hole 21 on the suppression plate 2 along the first direction, reaches the second cavity 17, and then is discharged from the heat storage tank 1 through the second opening 12, completing the heat storage process.

[0080] Example 3 1. Nitrogen at a temperature of 2000°C is transported downwardly along the first opening 11 into the heat storage tank 1, passes through the first cavity 16, reaches the first heat storage layer 13, and then exchanges heat with magnesium oxide. 2. After the primary heat exchange, the nitrogen gas passes through the through holes 21 on the suppression plate 2 in the first direction and reaches the second heat storage layer 14, where it undergoes secondary heat exchange with the graphite. 3. After the secondary heat exchange, the nitrogen gas passes through the through holes 21 on the suppression plate 2 in the first direction and reaches the third heat storage layer 15, where it undergoes a third heat exchange with the magnesium oxide. 4. After three heat exchanges, the nitrogen passes through the through hole 21 on the suppression plate 2 along the first direction, reaches the second cavity 17, and then is discharged from the heat storage tank 1 from the second opening 12, completing the heat storage process.

[0081] Example 4 1. Argon gas at a temperature of 1000°C is transported downwardly through the first opening 11 into the heat storage tank 1, passes through the first cavity 16, reaches the first heat storage layer 13, and then exchanges heat with the alumina. 2. After the primary heat exchange, the argon gas passes through the through holes 21 on the suppression plate 2 in the first direction and reaches the second heat storage layer 14, where it undergoes secondary heat exchange with the concrete. 3. After the secondary heat exchange, the argon gas passes through the through holes 21 on the suppression plate 2 along the first direction and reaches the third heat storage layer 15, where it undergoes a third heat exchange with the alumina. 4. After three heat exchanges, the argon gas passes through the through hole 21 on the suppression plate 2 along the first direction, reaches the second cavity 17, and then is discharged from the heat storage tank 1 through the second opening 12, completing the heat storage process; 5. Argon gas with a temperature below 30°C is fed upward from the second opening 12 into the heat storage tank 1, passes through the second cavity 17, and then through the through hole 21 on the suppression plate 2 to reach the third heat storage layer 15, where it contacts the alumina, causing the alumina to release heat once. 6. After the first heat release, the argon gas moves upward through the through holes 21 on the suppression plate 2 to reach the second heat storage layer 14, where it comes into contact with the concrete, causing the concrete to release heat for the second time. 7. After the second heat release, the argon gas moves upward through the through hole 21 on the suppression plate 2 to reach the first heat storage layer 13, and contacts the alumina. The alumina releases heat three times. Finally, after the argon gas absorbs heat, it passes through the first cavity 16 and is discharged from the heat storage tank 1 along the first opening 11.

[0082] In summary, the embodiments of the present application provide a high-temperature heat storage system and method composed of multiple layers of different materials. The system divides the interior of the heat storage tank into a first heat storage layer, a second heat storage layer, and a third heat storage layer. Each heat storage layer is composed of different heat storage media stacked together. The difference in thermal conductivity between different materials will make the heat more evenly distributed in the heat storage tank, thereby suppressing the formation of a thermocline layer in the heat storage tank. At the same time, heat transfer between different layers will be hindered due to material differences, thereby slowing down the formation of the thermocline layer and reducing the thickness of the thermocline layer. By suppressing the thermocline layer phenomenon, the efficiency of the heat storage system can be significantly improved, with less loss during storage and release, thereby improving the economic benefits of the heat storage system. The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0083] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0084] Finally, it should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "includes," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or terminal device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements that are inherent to such process, method, article, or terminal device. In the absence of further restrictions, an element defined by the phrase "comprises a ..." does not exclude the presence of additional identical elements in the process, method, article, or terminal device that includes the element.

[0085] The above is a detailed introduction to a high-temperature heat storage system and method composed of multiple layers of different materials provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core ideas of the present application. At the same time, for those skilled in the art, according to the ideas of the present application, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present application.

Claims

1. A high-temperature heat storage system composed of multiple layers of different materials, characterized in that: The system comprises a heat storage tank (1); The heat storage tank (1) is provided with a first opening (11) and a second opening (12) at two opposite ends along a first direction, respectively, and the first opening (11) is located above the second opening (12); The interior of the heat storage tank (1) is divided into a first heat storage layer (13), a second heat storage layer (14), and a third heat storage layer (15); the first opening (11) is connected to the interior of the first heat storage layer (13); and the second opening (12) is connected to the interior of the third heat storage layer (15); The first heat storage layer (13) is composed of a stacked first heat storage medium, the second heat storage layer (14) is composed of a stacked second heat storage medium, and the third heat storage layer (15) is composed of a stacked third heat storage medium.

2. The high-temperature heat storage system composed of multiple layers of different materials according to claim 1, characterized in that: The second heat storage layer (14) occupies 50% to 90% of the total internal volume of the heat storage tank (1).

3. The high-temperature heat storage system composed of multiple layers of different materials according to claim 2, characterized in that: The second heat storage layer (14) accounts for 65% to 80% of the total internal volume of the heat storage tank (1).

4. The high-temperature heat storage system composed of multiple layers of different materials according to claim 1, characterized in that: The ratio of the volume of the first heat storage layer (13) to the volume of the third heat storage layer (15) inside the heat storage tank (1) is (0.5-1):

1.

5. The high-temperature heat storage system composed of multiple layers of different materials according to claim 1, characterized in that: In the heat storage tank (1), a first cavity (16) is provided between the first heat storage layer (13) and the first opening (11); A second cavity (17) is provided between the third heat storage layer (15) and the second opening (12).

6. The high-temperature heat storage system composed of multiple layers of different materials according to claim 5, characterized in that: The first end (18) and the second end (19) of the heat storage tank (1) gradually decrease in size in the first direction; The dimensions of the first end (18) and the second end (19) on the side close to the second heat storage layer (14) are larger than the dimensions on the side away from the second heat storage layer.

7. The high-temperature heat storage system composed of multiple layers of different materials according to claim 1, characterized in that: The system further comprises a plurality of suppression plates (2), each of which is provided with a through hole (21); The plurality of suppression plates (2) are respectively arranged between the first heat storage layer (13) and the second heat storage layer (14), between the second heat storage layer (14) and the third heat storage layer (15), and between the third heat storage layer (15) and the second opening (12).

8. The high-temperature heat storage system composed of multiple layers of different materials according to claim 7, characterized in that: The size of the suppression plate (2) in the first direction is 0.1 m to 1 m.

9. A high temperature heat storage method composed of multiple layers of different materials, characterized in that: The method is applicable to the high-temperature heat storage system composed of multiple layers of different materials as claimed in any one of claims 1 to 8, and the method comprises: A heat storage fluid with a temperature of 500° C. to 2000° C. is fed into the heat storage tank (1) along the first opening (11); the heat storage fluid exchanges heat with the first heat storage medium after reaching the first heat storage layer (13); After the heat storage fluid undergoes the primary heat exchange, it reaches the second heat storage layer (14) along the first direction and then undergoes secondary heat exchange with the second heat storage medium; After the heat storage fluid undergoes secondary heat exchange, it reaches the third heat storage layer (15) along the first direction and undergoes a third heat exchange with the third heat storage medium; The heat storage fluid after the three heat exchanges is discharged from the heat storage tank (1) along the first direction from the second opening (12) to complete heat storage; Wherein, the heat storage fluid is any one of molten salt, thermal oil, quartz sand, air, nitrogen and argon; The first heat storage medium is any one of cast iron, stainless steel, alumina, magnesia, zirconia and phase change material with a particle size of less than 2 cm; The second heat storage medium is any one of sand, quartz, cement, concrete and graphite with a particle size of less than 2 cm; The third heat storage medium is any one of cast iron, stainless steel, aluminum oxide, magnesium oxide, zirconium oxide and phase change material with a particle size of less than 2 cm.

10. The high-temperature heat storage method comprising multiple layers of different materials according to claim 9, characterized in that: The first heat storage medium and the third heat storage medium are phase change materials; The phase change material is composed of a metal element wrapped in a particle coating; Wherein, the particle coating is a hollow particle composed of any one of aluminum silicate, calcium silicate, polyimide, aluminum oxide and zirconium oxide; The metal element is any one of iron, aluminum, tin, magnesium and copper.

Images