A high temperature thermal storage system and method of operation thereof comprising multiple layers of different materials

Abstract

The application provides a high-temperature heat storage system and a method thereof, which are composed of multiple layers of different materials. The system divides the heat storage tank into a first heat storage layer, a second heat storage layer and a third heat storage layer, and each heat storage layer is composed of different heat storage media stacked. The difference in heat conduction performance between different materials can make heat more evenly distributed in the heat storage tank, thereby inhibiting the formation of a thermocline in the heat storage tank. At the same time, the heat transfer between different layers is hindered due to the difference in materials, thereby slowing down the formation speed of the thermocline and reducing the thickness of the thermocline. By inhibiting the thermocline phenomenon, the efficiency of the heat storage system can be significantly improved, the loss during storage and release is less, and the economic benefit of the heat storage system is improved.

Description

Technical Field

[0001] This application relates to the field of thermal energy storage technology, and more specifically, to a high-temperature thermal energy storage system and method composed of multiple layers of different materials. Background Technology

[0002] With the accelerating global energy transition, thermal energy storage technology has received increasing attention due to its crucial role in energy time regulation and improving energy utilization efficiency. Particularly 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 many challenges in practical applications, among which the thermocline phenomenon is one of the main factors affecting the efficiency of thermal energy storage systems.

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

[0004] To address the aforementioned problems, this application provides a high-temperature thermal storage system and method composed of multiple layers of different materials. The system divides the interior of the thermal storage tank into a first, second, and third thermal storage layer, each composed of stacked different thermal storage media. The differences in thermal conductivity between the different materials ensure a more uniform distribution of heat within the storage tank, thereby suppressing the formation of a thermocline layer. Simultaneously, heat transfer between different layers is hindered by material differences, slowing down the formation rate and reducing the thickness of the thermocline layer. By suppressing thermocline formation, the efficiency of the thermal storage system can be significantly improved, resulting in less loss during storage and release, thus enhancing the economic benefits of the thermal storage system.

[0005] In a first aspect, this application provides a high-temperature thermal storage system composed of multiple layers of different materials, the system including a thermal storage tank (1);

[0006] The heat storage tank (1) has a first opening (11) and a second opening (12) at opposite ends along the first direction, with the first opening (11) located above the second opening (12).

[0007] 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) communicates with the interior of the first heat storage layer (13), and the second opening (12) communicates with the interior of the third heat storage layer (15).

[0008] The first heat storage layer (13) is composed of a first heat storage medium stacked on top of each other, the second heat storage layer (14) is composed of a second heat storage medium stacked on top of each other, and the third heat storage layer (15) is composed of a third heat storage medium stacked on top of each other.

[0009] Furthermore, the second heat storage layer (14) occupies 50% to 90% of the total internal volume of the heat storage tank (1).

[0010] Furthermore, the second heat storage layer (14) occupies 65% to 80% of the total internal volume of the heat storage tank (1).

[0011] Furthermore, 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.

[0012] 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);

[0013] A second cavity (17) is provided between the third heat storage layer (15) and the second opening (12).

[0014] Furthermore, the dimensions of the first end (18) and the second end (19) of the heat storage tank (1) gradually decrease in the first direction;

[0015] The dimensions of the first end (18) and the second end (19) on the side closer to the second thermal storage layer (14) are larger than the dimensions on the side farther away from the second thermal storage layer.

[0016] Furthermore, the system also includes multiple suppression plates (2), and the suppression plates (2) are provided with through holes (21);

[0017] 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).

[0018] Furthermore, the size of the suppression plate (2) in the first direction is 0.1 m to 1 m.

[0019] Secondly, this application provides a high-temperature thermal storage method composed of multiple layers of different materials. The method is applicable to the high-temperature thermal storage system composed of multiple layers of different materials described in the first aspect above. The method includes:

[0020] A heat storage fluid with a temperature of 500 ℃~2000 ℃ is fed into the heat storage tank (1) through the first opening (11). After the heat storage fluid reaches the first heat storage layer (13), it exchanges heat with the first heat storage medium once.

[0021] After the heat storage fluid undergoes the first heat exchange, it reaches the second heat storage layer (14) along the first direction and then undergoes a second heat exchange with the second heat storage medium.

[0022] After the secondary heat exchange, the heat storage fluid reaches the third heat storage layer (15) along the first direction and undergoes three heat exchanges with the third heat storage medium.

[0023] The heat storage fluid after the three heat exchanges is discharged from the heat storage tank (1) through the second opening (12) along the first direction to complete the heat storage;

[0024] The heat storage fluid is any one of molten salt, heat transfer oil, quartz sand, air, nitrogen, and argon.

[0025] The first heat storage medium is any one of cast iron, stainless steel, alumina, magnesium oxide, zirconium oxide and phase change material with a particle size of <2 cm;

[0026] The second heat storage medium is any one of sand, quartz, cement, concrete and graphite with a particle size of <2 cm;

[0027] The third heat storage medium is any one of cast iron, stainless steel, alumina, magnesium oxide, zirconium oxide and phase change material with a particle size of <2 cm;

[0028] Furthermore, the first thermal storage medium and the third thermal storage medium are phase change materials;

[0029] The phase change material is composed of a metallic element coated with particles;

[0030] The particle coating is composed of hollow particles made of any one of aluminum silicate, calcium silicate, polyimide, alumina, and zirconium oxide.

[0031] The metallic element is any one of iron, aluminum, tin, magnesium, and copper.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] 1. This application provides a high-temperature thermal storage system composed of multiple layers of different materials. The system includes a thermal storage tank with a first opening and a second opening at opposite ends along a first direction. The interior of the thermal storage tank is divided into a first thermal storage layer, a second thermal storage layer, and a third thermal storage layer. The first thermal storage layer is composed of stacked first thermal storage media, the second thermal storage layer is composed of stacked second thermal storage media, and the third thermal storage layer is composed of stacked third thermal storage media. In practice, since each thermal storage layer is composed of different thermal storage media, the difference in thermal conductivity between different materials will inhibit the diffusion of heat, thereby inhibiting the formation of a temperature gradient layer inside the thermal storage tank. At the same time, the heat transfer between different layers is hindered by the material differences, which can slow down the formation rate of the temperature gradient layer. By inhibiting the formation of the temperature gradient layer, the efficiency of the thermal storage system can be further improved, with less loss during storage and release, thereby improving the economic benefits of the thermal storage system.

[0034] 2. A high-temperature thermal storage method composed of multiple layers of different materials, wherein the system in which the method is applied includes a first thermal storage layer, a second thermal storage layer and a third thermal storage layer, and each layer is composed of different thermal storage materials, which can more effectively disperse and store thermal energy; and in the method provided in this application, the different materials selected have different thermal conductivity and heat capacity, which helps to reduce the accumulation of thermal energy in the same layer, thereby suppressing the formation of a thermocline; by setting up a three-stage heat exchange, the thermal storage fluid exchanges heat layer by layer in the thermal storage tank, and the thermal energy is gradually released and stored in each layer of medium, realizing the uniform distribution of thermal energy and further suppressing the formation of a thermocline. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the structure of a high-temperature thermal storage system composed of multiple layers of different materials, as proposed in an embodiment of this application, is shown.

[0037] Figure 2 A schematic diagram of the structure of the suppression plate proposed in an embodiment of this application is shown;

[0038] Figure 3 A flowchart of a high-temperature thermal storage method composed of multiple layers of different materials, as proposed in an embodiment of this application, is shown.

[0039] Figure 4 A flowchart illustrating the heat release method of a high-temperature thermal storage system composed of multiple layers of different materials, as proposed in an embodiment of this application, is shown.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Thermal storage tank; 11. First opening; 12. Second opening; 13. First thermal storage layer; 14. Second thermal storage layer; 15. Third thermal storage layer; 16. First cavity; 17. Second cavity; 18. First end; 19. Second end;

[0042] 2. Suppression plate; 21. Through hole. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] In the accompanying drawings, the size of constituent elements, the thickness of layers, or areas may sometimes be exaggerated for clarity. Therefore, any implementation of this disclosure is not necessarily limited to the dimensions shown in the drawings, and the shapes and sizes of the components in the drawings do not reflect true proportions. Furthermore, the drawings schematically illustrate ideal examples, and any implementation of this disclosure is not limited to the shapes or values ​​shown in the drawings.

[0045] Among related technologies, thermal energy storage technology has received increasing attention due to its key role in energy time regulation and improving energy utilization efficiency, as the global energy transition accelerates. Especially in fields 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.

[0046] Thermal energy storage technology refers to the technology of converting thermal energy into other forms of energy for storage through certain technical means, and then converting it back into thermal energy for utilization when needed. Its principles mainly involve the first and second laws of thermodynamics, utilizing the characteristics of substances such as temperature differences, phase transition processes, or chemical reactions to store and release thermal energy.

[0047] 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.

[0048] The thermocline, also known as the "temperature jump layer" or "temperature gradient layer," is a layer in thermal energy storage systems that forms due to uneven temperature gradient distribution within the system. It primarily manifests as a non-idealized stratification of heat transfer within the energy storage medium, separating two or more fluids with significantly different temperatures. The characteristics of the thermocline mainly include:

[0049] 1. The thermocline is a region where the temperature changes drastically, with a large temperature gradient, meaning that the temperature changes significantly over a very short distance.

[0050] 2. As an interface, it separates fluids at different temperatures. This separation helps maintain the thermal efficiency of the system, but it may also lead to uneven heat distribution.

[0051] The formation of a thermocline prevents the efficient utilization of heat energy during storage and release. Heat energy tends to flow from high-temperature to low-temperature regions, and the thermocline hinders this process, preventing the effective storage or release of some heat energy. This increases system heat loss and reduces energy storage efficiency. Furthermore, the presence of a thermocline can lead to system instability, affecting the long-term performance of energy storage devices.

[0052] Current technological solutions largely focus on optimizing energy storage materials, but due to the complexity of the thermocline phenomenon, existing methods have limited effectiveness in suppressing its formation. This problem is particularly pronounced in large-scale energy storage systems, becoming a constraint on further improving system efficiency and economics.

[0053] Based on the problems existing in related technologies, this application provides a high-temperature thermal storage system and method composed of multiple layers of different materials. By setting a layered structure inside the thermal storage tank, and setting each layer to be composed of different thermal storage media, the temperature distribution inside the thermal storage tank is made more uniform by utilizing the differences in thermal conductivity of different thermal storage media, thereby suppressing the formation of a temperature gradient layer and reducing the impact of the temperature gradient layer on the mass transfer efficiency and energy storage effect inside the thermal storage tank.

[0054] For specific implementation, please refer to Figure 1 The system includes a thermal storage tank 1;

[0055] The heat storage tank 1 has a first opening 11 and a second opening 12 at opposite ends along the first direction, with the first opening 11 located above the second opening 12.

[0056] 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 communicates with the interior of the first heat storage layer 13, and the second opening 12 communicates with the interior of the third heat storage layer 15.

[0057] The first heat storage layer 13 is composed of stacked first heat storage media, the second heat storage layer 14 is composed of stacked second heat storage media, and the third heat storage layer 15 is composed of stacked third heat storage media.

[0058] It should be noted that the thermal storage tank 1 is a sealed tank that is resistant to high temperatures and corrosion.

[0059] The cross-section of the heat storage tank 1 can be circular, square, rhomboid, or elliptical, etc.;

[0060] The first direction x is the direction that extends along the length of the thermal storage tank 1;

[0061] The shapes of the first thermal storage layer 13, the second thermal storage layer 14 and the third thermal storage layer 15 are adapted to the shape of the thermal storage tank 1.

[0062] In specific implementation, a first heat storage medium is stacked inside the heat storage tank 1 to form a first heat storage layer 13. A second heat storage medium is stacked below the first heat storage layer 13 to form a second heat storage layer 14 inside the heat storage tank 1. A third heat storage medium is stacked below the second heat storage layer 14 to form a third heat storage layer 15 inside the heat storage tank 1. The heat storage fluid enters the heat storage tank 1 downwards through the first opening 11, first reaching the first heat storage layer 13. As the heat storage fluid gradually flows downwards, it exchanges heat with the first heat storage medium, storing some of the 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, thus completing the heat storage process.

[0063] This application embodiment employs a layered design within the thermal storage tank 1, utilizing materials with varying thermal properties (such as 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 variations in parameters such as heat capacity and thermal conductivity across each layer. This results in a more uniform heat distribution along the first direction within the thermal storage tank 1, thereby helping to suppress the formation of a thermocline. Due to the differences in thermal properties between the materials, heat transfer between layers is hindered, thus slowing down the formation rate of the thermocline. By suppressing the thermocline phenomenon, the efficiency of the thermal energy storage system can be improved. The layered structure within the thermal storage tank 1, achieving a more uniform heat distribution, also reduces heat loss during storage and release, contributing to improved overall efficiency of the thermal storage system and enhanced energy utilization efficiency.

[0064] The first opening 11 and the second opening 12 are respectively connected to the interior of the first thermal storage layer 13 and the third thermal storage layer 15, and the first opening 11 is located above the second opening 12, so that heat can be transferred more flexibly between different thermal storage layers along the first direction, further reducing the impact of the thermocline on mass transfer efficiency.

[0065] This application embodiment, through a layered design within the thermal storage tank 1 and the use of different material combinations, enables the system to adapt to various application scenarios and load requirements. During implementation, the system's performance and cost can be further optimized by adjusting the material ratios and number of layers. This system provides new ideas and methods for thermal energy storage technology, contributing to the continued development and innovation in this field.

[0066] In specific implementation, when using the system provided in the embodiments of this application for heat release treatment, the cold fluid is sent upward into the heat storage tank 1 along the second opening 12. The cold fluid passes upward sequentially through the third heat storage layer 15, the second heat storage layer 14 and the first heat storage layer 13, and exchanges heat with the third heat storage medium, the second heat storage medium and the first heat storage medium to achieve heat release.

[0067] In specific implementation, the first heat storage medium is any one of cast iron, stainless steel, alumina, magnesium oxide, zirconium oxide and phase change material with a particle size of <2 cm;

[0068] The second heat storage medium is any one of sand, quartz, cement, concrete and graphite with a particle size of <2 cm.

[0069] The third heat storage medium is any one of cast iron, stainless steel, alumina, magnesium oxide, zirconium oxide and phase change material with a melt particle size of <2 cm;

[0070] The first thermal storage medium selected in the embodiments of this application all have high density and specific heat capacity, as well as low thermal conductivity, which is more conducive to suppressing the expansion of the thermocline during the heat release phase.

[0071] Compared to the first thermal storage medium, the second thermal storage medium has a lower density and specific heat capacity, as well as a lower thermal conductivity, which is more conducive to the rapid heat absorption of the second thermal storage layer 14 and its rapid expansion to form a high-temperature region.

[0072] Compared to the second thermal storage medium, the third thermal storage medium has a larger density and specific heat capacity, as well as a lower thermal conductivity, which is more conducive to suppressing the formation of the oblique temperature layer at the third thermal storage layer 15 and the second opening 12, and can especially reduce the thickness of the oblique temperature layer at the second opening 12.

[0073] In some embodiments, see Figure 1 The second heat storage layer 14 occupies 50% to 90% of the total internal volume of the heat storage tank 1.

[0074] It should be noted that the volume of the second thermal storage layer 14 is the total volume of the stacked thermal storage media.

[0075] In specific implementation, by setting the second thermal storage layer 14 to occupy 50% to 90% of the total internal volume of the thermal storage tank 1, the second thermal storage layer 14 has the largest volume compared to the first and third storage layers. A large amount of thermal energy in the thermal storage fluid is stored and dispersed in this layer. Furthermore, by setting the material of the second thermal storage layer 14 to be different from that of the first thermal storage layer 13 and the third thermal storage layer 15, it can more effectively absorb and disperse the thermal energy from the thermal storage fluid, reduce the accumulation of thermal energy in the same layer, achieve a uniform distribution of thermal energy in the second thermal storage medium, reduce the thermal energy diffusing to the third thermal storage layer 15, extend the high-temperature region in the thermal storage tank 1, further suppress the formation of the thermocline layer, and reduce the thickness of the thermocline layer at the second opening 12. After the thermocline layer is suppressed, it also helps to enhance the stability of the system. Due to the more uniform distribution of thermal energy, the temperature fluctuation of the system is reduced, thereby improving the reliability and durability of the system.

[0076] In some embodiments, see Figure 1 The second heat storage layer 14 occupies 65% to 80% of the total internal volume of the heat storage tank 1.

[0077] In practical implementation, by optimizing the proportion of the second heat storage layer 14 within the total volume of the heat storage tank 1, the high-temperature zone within the heat storage tank 1 can be set more appropriately. This ensures that more heat storage medium can be kept at a higher temperature, improving the overall thermal efficiency of the system. It also helps reduce heat loss, as heat in high-temperature zones is less likely to dissipate into the environment through heat conduction or convection.

[0078] In some embodiments, see Figure 1 The ratio of the volume of the first heat storage layer 13 to that of the third heat storage layer 15 inside the heat storage tank 1 is (0.5~1):1.

[0079] In specific implementation, 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 can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1 or 1:1.

[0080] By adjusting the volume ratio of the first heat storage layer 13 to the third heat storage layer 15, the temperature distribution inside the heat storage tank 1 can be controlled more effectively. Simultaneously, these two layers act as a "buffer zone" for thermal energy, inhibiting its diffusion to the first opening 11 and the second opening 12 of the heat storage tank 1. Optimizing the volumes of the first heat storage layer 13 and the second heat storage layer 14 also helps reduce the temperature gradient inside the heat storage tank 1, thereby suppressing the formation of temperature gradients at the first opening 11 and the second opening 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, improving thermal energy utilization and reducing energy waste.

[0081] In a more preferred embodiment, 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.

[0082] 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;

[0083] A second cavity 17 is provided between the third heat storage layer 15 and the second opening 12.

[0084] 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 total volume of the heat storage tank 1 as the first cavity 16.

[0085] By setting up a first cavity 16 and a second cavity 17, two temperature buffer zones are added at the first opening 11 and the second opening 12 of the thermal storage tank 1. When the thermal storage fluid enters the thermal storage tank 1 through the first opening 11, the first cavity 16 can absorb and disperse some of the heat energy, slowing down the direct impact of the thermal storage fluid on the first thermal storage layer 13, thereby reducing the rate of temperature gradient formation. When the thermal storage fluid completes its heat storage and flows out from the third thermal storage layer 15, the second cavity 17 can act as another temperature buffer, further reducing the diffusion of heat energy to the outside of the thermal storage tank 1, maintaining the uniformity of the internal temperature of the thermal storage tank 1, slowing down temperature fluctuations within the system, and reducing the thickness of the inclined temperature layer at the opening of the thermal storage tank 1. At the same time, a stable temperature environment also helps to extend the service life of the thermal storage medium and the system, reducing failures and damage caused by temperature fluctuations.

[0086] In some embodiments, see Figure 1 The dimensions of the first end 18 and the second end 19 of the heat storage tank 1 gradually decrease in the first direction;

[0087] The dimensions of the first end 18 and the second end 19 on the side closer to the second thermal storage layer 14 are larger than the dimensions on the side farther away from the second thermal storage layer.

[0088] It should be noted that the first end 18 of the heat storage tank 1 is the end where the first cavity 16 is provided, and the second end 19 is the end where the second cavity 17 is provided;

[0089] 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 first cavity 16 and the second cavity 17 are trapezoidal in shape.

[0090] The dimensions of the first end 18 and the second end 19 on the side near the second thermal storage layer 14 are expressed as: the dimensions of the connection between the first end 18 and the second end 19 of the thermal storage tank 1 and the middle part of the thermal storage tank 1.

[0091] The dimensions of the first end 18 and the second end 19 on the side away from the second reservoir are expressed as: 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;

[0092] The first end 18 of the heat storage tank 1 gradually tapers upward along the first direction, and the second end 19 of the heat storage tank 1 gradually tapers downward along the first direction.

[0093] In practice, 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, reducing the formation of turbulence or eddies inside the heat storage tank 1. This helps to suppress the formation of the thermocline and reduce the ineffective diffusion of heat energy to both ends of the heat storage tank 1, so that more heat energy can be effectively stored in the heat storage medium.

[0094] Since the flow velocity of the fluid at both ends of the heat storage tank 1 can be gradually changed, the heat energy diffusion and mixing caused by sudden velocity changes are avoided. This helps to maintain the uniformity of the internal temperature of the heat storage tank 1, reduce the internal temperature gradient of the heat storage tank 1, increase the mass transfer efficiency, and improve the heat energy storage efficiency.

[0095] In some embodiments, see Figure 1 and Figure 2 The system also includes multiple suppression plates 2, and the suppression plates 2 are provided with through holes 21;

[0096] 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.

[0097] It should be noted that the shape of the suppression plate 2 is adapted to the shape of the heat storage tank 1;

[0098] The two ends of the suppression plate 2 are fixed to the inner wall of the heat storage tank 1 in the horizontal direction.

[0099] By setting up the suppression plate 2, heat energy is transferred both through the heat storage medium and diffused through the through-holes 21 on the suppression plate 2, thereby slowing down the heat transfer rate inside the heat storage tank 1 and suppressing the formation of a large temperature gradient during heat transfer, thus inhibiting the formation of a temperature gradient layer. Furthermore, by setting up the suppression plate, the first, second, and third heat storage media are all stacked on the suppression plate 2, reducing the movement of the heat storage media along the first direction after being impacted by fluid, thus maintaining the stability of each heat storage layer within the heat storage tank 1.

[0100] In practice, the diameter of the through hole 21 can be 5 mm to 100 mm. The number of through holes 21 can be 50 to 300.

[0101] During implementation, if the through-holes 21 are too large or too numerous, heat transfer will be too rapid, failing to effectively suppress the formation of the thermocline. If the through-holes 21 are too small or too few, the heat transfer efficiency will be affected, reducing the system performance. Therefore, selecting appropriate diameters and numbers of through-holes 21 based on the size of the thermal storage tank 1 and the fluid being transported is of great significance for suppressing the thermocline and improving heat transfer efficiency.

[0102] 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, or glass fiber composite material, etc. The suppression plate 2 composed of these materials has good thermal conductivity and high-temperature resistance, enabling it to withstand long-term operation in high-temperature environments. This ensures that heat energy can be effectively transferred through the through-hole 21 and withstand long-term operation in high-temperature environments. Simultaneously, the material also needs to possess certain strength and toughness to ensure that the suppression plate 2 will not be damaged due to excessive stress during use.

[0103] In some embodiments, see Figure 1 The size of the suppression plate 2 in the first direction is 0.1 m to 1 m.

[0104] 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.

[0105] In practice, it is necessary to achieve the effect of suppressing the formation of the inclined temperature layer by suppressing plate 2, while also avoiding the suppression plate 2 occupying too much space in the heat storage tank 1, which would reduce the high-temperature area formed by the second heat storage layer 14. Reasonably limiting the thickness of the suppression plate 2 also helps to reduce the size of the through hole 21 along the first direction, avoiding the through hole 21 being too deep and causing uneven temperature distribution on the suppression plate 2.

[0106] This application also provides a high-temperature thermal storage method composed of multiple layers of different materials. This method is applicable to high-temperature thermal storage devices composed of multiple layers of different materials. (See also...) Figure 3 The method includes:

[0107] Step S1: The heat storage fluid with a temperature of 500 ℃~2000 ℃ is sent into the heat storage tank 1 through the first opening 11. After the heat storage fluid reaches the first heat storage layer 13, it exchanges heat with the first heat storage medium once.

[0108] Step S2: After the heat storage fluid undergoes the first heat exchange, it reaches the second heat storage layer 14 along the first direction and then undergoes a second heat exchange with the second heat storage medium.

[0109] 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 three heat exchanges with the third heat storage medium.

[0110] Step S4: The heat storage fluid after the three heat exchanges is discharged from the heat storage tank 1 through the second opening 12 along the first direction to complete the heat storage;

[0111] The heat storage fluid is any one of molten salt, heat transfer oil, quartz sand, air, nitrogen, and argon.

[0112] The first heat storage medium is any one of cast iron, stainless steel, alumina, magnesium oxide, zirconium oxide and phase change material with a particle size of <2 cm;

[0113] The second heat storage medium is any one of sand, quartz, cement, concrete and graphite with a particle size of <2 cm;

[0114] The third heat storage medium is any one of molten salt with a particle size of <2 cm, heat transfer oil, quartz sand, air, nitrogen, argon and phase change material.

[0115] In practical implementation, in the thermal storage system, the thermal storage fluid first enters the first layer of thermal storage medium and exchanges heat with it, transferring heat to the first thermal storage medium. As the temperature of the thermal storage fluid decreases, it continues to flow to the second thermal storage medium for another heat exchange. This process continues until the thermal storage fluid flows out of the final third thermal storage medium, at which point the thermal storage fluid has transferred most of its heat to the second thermal storage medium. Because the first thermal storage layer 13, the second thermal storage layer 14, and the third thermal storage layer 15 in the system proposed in this application are composed of thermal storage media made of different materials, and because the thermal properties (such as thermal conductivity, heat capacity, etc.) of each thermal storage medium are different, their thermal responses to the thermal storage fluid are also different. This helps to form a more uniform temperature gradient during the thermal storage process and effectively suppresses the formation of a temperature gradient layer. After the temperature gradient layer is reduced, the uniformity of the temperature distribution inside the thermal storage tank 1 is improved, which helps to improve the thermal efficiency of the thermal energy storage system. The multi-layer thermal storage medium structure allows more thermal energy to be stored in the thermal storage medium and released when needed.

[0116] In practical implementation, molten salt and heat transfer oil have high thermal conductivity and high heat capacity, while air, nitrogen, and argon have high thermal diffusivity, making them all suitable for energy storage using the system provided in this application. Quartz sand has relatively low thermal conductivity but high heat capacity and stability, which can improve thermal storage efficiency.

[0117] The material selected for the first heat storage medium has a high melting point, high thermal stability and good thermal conductivity, making it suitable for direct heat exchange with the input high-temperature heat storage fluid as the first heat storage layer 13, and capable of effectively absorbing and storing the heat of the high-temperature heat storage fluid.

[0118] The second thermal storage medium is made of materials with lower cost and moderate thermal conductivity, making it suitable as a second thermal storage layer and enabling it to store more heat more stably.

[0119] In practice, when the temperature of the heat storage fluid is below 1000 ℃, the heat storage fluid can be molten salt, heat transfer oil or air;

[0120] When the temperature of the thermal storage fluid is higher than 1000 ℃, it is further determined whether the thermal storage fluid will react with the thermal storage medium. If a reaction occurs, nitrogen or argon is selected as the thermal storage fluid.

[0121] In practice, the particle size of the first, second, and third heat storage media is all <2 cm, resulting in a large specific surface area. Since heat is stored not only inside the heat storage media but also at the interface between the heat storage media and the heat storage fluid, the larger specific surface area of ​​the heat storage media allows it to store more heat.

[0122] In practice, the first heat storage medium has good physicochemical stability and does not react with the heat storage fluid. When the heat storage fluid is below 1000 ℃, the first heat storage medium can be cast iron or stainless steel; when the heat storage fluid is below 1500 ℃, the first heat storage medium can be alumina; when the heat storage fluid is below 2000 ℃, the first heat storage medium can be magnesium oxide or zirconium oxide.

[0123] In practice, the second thermal storage medium has good physicochemical stability and does not react with the thermal storage fluid. When the thermal storage fluid is below 1000 ℃, the second thermal storage medium can be sand, quartz, or cement; when the thermal storage fluid is below 1500 ℃, the second thermal storage medium can be high-temperature concrete; and when the thermal storage fluid is below 2000 ℃, the second thermal storage medium can be graphite.

[0124] In practical implementation, the third heat storage medium has good physicochemical stability and does not react with the heat storage fluid. For heat storage fluids below 1000 ℃, cast iron or stainless steel can be used as the third heat storage medium; for heat storage fluids below 1500 ℃, alumina can be used; and for heat storage fluids below 2000 ℃, magnesium oxide or zirconium oxide can be used.

[0125] In some embodiments, this application also provides a method for releasing heat from a high-temperature thermal storage system composed of multiple layers of different materials, specifically including:

[0126] Step S11: Cold fluid with a temperature below 30 °C is fed upward into the heat storage tank 1 through the second opening 12. After reaching the third heat storage layer 15, it comes into contact with the third heat storage medium, and the third heat storage medium begins to release heat once.

[0127] Step S12: After the first heat release, the cold fluid rises to the second heat storage layer 14 and comes into contact with the second heat storage medium, where the second heat storage medium releases heat a second time.

[0128] Step S13: After the cold fluid has undergone two heat releases, it rises to the first heat storage layer 13 and comes into contact with the first heat storage medium. The first heat storage medium releases heat three times. Finally, after the fluid absorbs heat, it is discharged from the heat storage tank 1 through the first opening 11.

[0129] By setting a first thermal storage layer 13, a second thermal storage layer 14, and a third thermal storage layer 15 in the system, and using different thermal storage media, the third thermal storage medium can suppress the expansion of the thermocline during the heat release process, the second thermal storage medium can allow the heat that cannot be extracted from the thermocline to be carried away by the cold fluid as much as possible, and the first thermal storage medium can further suppress the expansion of the heat-releasing thermocline, thereby improving the thermal storage efficiency and energy density.

[0130] In some embodiments, the first thermal storage medium and the third thermal storage medium are phase change materials;

[0131] The phase change material is composed of a metallic element coated with particles;

[0132] The particle coating is composed of hollow particles made of any one of aluminum silicate, calcium silicate, polyimide, alumina, and zirconium oxide.

[0133] The metallic element is any one of iron, aluminum, tin, magnesium, and copper.

[0134] It should be noted that, based on the characteristics of phase change materials, they undergo a phase change at a certain temperature, thereby absorbing or releasing a large amount of heat, which helps to regulate the temperature inside the thermal storage system, reduce the temperature gradient, and improve thermal efficiency.

[0135] In practice, the phase change material consists of a particle coating and a metallic element. When the metallic element melts due to heat, it can be preserved in the particle coating to avoid contaminating the first or third heat storage medium.

[0136] The granular coating is composed of highly thermally conductive materials such as aluminum silicate, calcium silicate, polyimide, alumina, and zirconium oxide, and has excellent thermal conductivity.

[0137] Using elemental metals as the core of a phase change material not only increases the heat capacity of the first or third thermal storage medium but also possesses good thermal conductivity and ductility, which helps to distribute heat evenly within the first or third thermal storage medium. Combined with a multi-layered thermal storage medium design, this helps to reduce the formation of thermoclines.

[0138] In practice, when the thermal storage fluid is below 1000 ℃, the phase change material possesses phase change heat, which can maintain the temperature near its melting point. Near the end of the thermal storage process, the third thermal storage medium, i.e., the phase change material, will maintain its temperature near its melting point, thus suppressing the temperature of the second opening 12 and preventing the expansion of the thermocline. Conversely, at the end of the heat release phase, the temperature of the first opening 11 is maintained near its melting point by the first thermal storage medium, i.e., the phase change material, preventing the thermocline from expanding and thus reducing its thickness.

[0139] To enable those skilled in the art to better understand this application, the following embodiments will be used to provide a detailed description of a high-temperature thermal storage system and method composed of multiple layers of different materials.

[0140] Example 1

[0141] 1. Argon gas at a temperature of 1000 ℃ is delivered downward through the first opening 11 into the heat storage tank 1. After passing through the first cavity 16, it reaches the first heat storage layer 13 and exchanges heat with alumina once.

[0142] 2. After the first heat exchange, the argon gas travels along the first direction, passes through the through hole 21 on the suppression plate 2, reaches the second heat storage layer 14, and then undergoes a second heat exchange with the concrete.

[0143] 3. After the second heat exchange, the argon gas travels along the first direction, passes through the through hole 21 on the suppression plate 2, reaches the third heat storage layer 15, and then undergoes a third heat exchange with the alumina.

[0144] 4. After three heat exchanges, the argon gas passes through the through hole 21 on the suppression plate 2 in the first direction, reaches the second cavity 17, and then exits the heat storage tank 1 from the second opening 12, completing the heat storage process.

[0145] Example 2

[0146] 1. Heat transfer oil at a temperature of 500 ℃ is delivered downward through the first opening 11 into the heat storage tank 1. After passing through the first cavity 16, it reaches the first heat storage layer 13 and undergoes a heat exchange with the cast iron.

[0147] 2. After the first heat exchange, the heat transfer oil travels along the first direction, through the through hole 21 on the suppression plate 2, to the second heat storage layer 14, where it undergoes a second heat exchange with the sand and gravel.

[0148] 3. After the secondary heat exchange, the heat transfer oil travels along the first direction, passes through the through hole 21 on the suppression plate 2, reaches the third heat storage layer 15, and then undergoes a third heat exchange with the cast iron.

[0149] 4. After three heat exchanges, the heat transfer oil passes through the through hole 21 on the suppression plate 2 in the first direction, reaches the second cavity 17, and then is discharged from the heat storage tank 1 through the second opening 12, thus completing the heat storage process.

[0150] Example 3

[0151] 1. Nitrogen gas at a temperature of 2000 ℃ is delivered downward through the first opening 11 into the heat storage tank 1. After passing through the first cavity 16, it reaches the first heat storage layer 13 and undergoes a heat exchange with magnesium oxide.

[0152] 2. After the first heat exchange, the nitrogen gas travels along the first direction, passes through the through hole 21 on the suppression plate 2, reaches the second heat storage layer 14, and then undergoes a second heat exchange with the graphite.

[0153] 3. After the secondary heat exchange, the nitrogen gas travels along the first direction, passes through the through hole 21 on the suppression plate 2, reaches the third heat storage layer 15, and then undergoes a third heat exchange with magnesium oxide.

[0154] 4. After three heat exchanges, the nitrogen gas passes through the through hole 21 on the suppression plate 2 in the first direction, reaches the second cavity 17, and then exits the heat storage tank 1 from the second opening 12, completing the heat storage process.

[0155] Example 4

[0156] 1. Argon gas at a temperature of 1000 ℃ is delivered downward through the first opening 11 into the heat storage tank 1. After passing through the first cavity 16, it reaches the first heat storage layer 13 and exchanges heat with alumina once.

[0157] 2. After the first heat exchange, the argon gas travels along the first direction, passes through the through hole 21 on the suppression plate 2, reaches the second heat storage layer 14, and then undergoes a second heat exchange with the concrete.

[0158] 3. After the second heat exchange, the argon gas travels along the first direction, passes through the through hole 21 on the suppression plate 2, reaches the third heat storage layer 15, and then undergoes a third heat exchange with the alumina.

[0159] 4. After three heat exchanges, the argon gas passes through the through hole 21 on the suppression plate 2 in the first direction, reaches the second cavity 17, and then exits the heat storage tank 1 from the second opening 12, completing the heat storage process.

[0160] 5. Argon gas with a temperature below 30 ℃ is sent upward into the heat storage tank 1 through the second opening 12, 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 and come into contact with alumina. The alumina then begins to release heat once.

[0161] 6. After the first heat release, the argon gas rises and reaches the second heat storage layer 14 through the through hole 21 on the suppression plate 2, where it comes into contact with the concrete, and the concrete releases heat a second time.

[0162] 7. After the argon gas undergoes secondary heat release, it rises upward and reaches the first heat storage layer 13 through the through hole 21 on the suppression plate 2. It comes into contact with the alumina, and 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 through the first opening 11.

[0163] In summary, the embodiments of this application provide a high-temperature thermal storage system and method composed of multiple layers of different materials. This system divides the interior of the thermal storage tank into a first thermal storage layer, a second thermal storage layer, and a third thermal storage layer, with each layer composed of stacked different thermal storage media. The differences in thermal conductivity between the different materials allow for a more uniform distribution of heat within the thermal storage tank, thereby suppressing the formation of a thermocline. Simultaneously, heat transfer between different layers is hindered by material differences, thus slowing down the formation rate and reducing the thickness of the thermocline. By suppressing the thermocline phenomenon, the efficiency of the thermal storage system can be significantly improved, resulting in less loss during storage and release, and enhancing the economic benefits of the thermal storage system.

[0164] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0165] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0166] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0167] The above provides a detailed description of a high-temperature thermal storage system and method composed of multiple layers of different materials provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A high-temperature thermal storage system composed of multiple layers of different materials, characterized in that, The system includes a thermal storage tank (1); The heat storage tank (1) has a first opening (11) and a second opening (12) at opposite ends along the first direction, with the first opening (11) located above the second opening (12). 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) communicates with the interior of the first heat storage layer (13), and the second opening (12) communicates with the interior of the third heat storage layer (15). The first heat storage layer (13) is composed of stacked first heat storage media, the second heat storage layer (14) is composed of stacked second heat storage media, and the third heat storage layer (15) is composed of stacked third heat storage media; The density, thermal conductivity, and specific heat capacity of the first thermal storage medium are all greater than those of the second thermal storage medium, and the density and specific heat capacity of the third thermal storage medium are greater than those of the second thermal storage medium. The second heat storage layer (14) occupies 50% to 90% of the total internal volume of the heat storage tank (1); 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.

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

3. The high-temperature thermal 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).

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

5. The high-temperature thermal storage system composed of multiple layers of different materials according to claim 1, characterized in that, The system also includes multiple suppression plates (2), and the suppression plates (2) are provided with through holes (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).

6. The high-temperature thermal storage system composed of multiple layers of different materials according to claim 5, characterized in that, The size of the suppression plate (2) in the first direction is 0.1 m to 1 m.

7. A high-temperature heat storage method composed of multiple layers of different materials, characterized in that, The method is applicable to the high-temperature thermal storage system composed of multiple layers of different materials as described in any one of claims 1 to 6, and the method includes: A heat storage fluid with a temperature of 500 ℃~2000 ℃ is fed into the heat storage tank (1) through the first opening (11). After the heat storage fluid reaches the first heat storage layer (13), it exchanges heat with the first heat storage medium once. After the heat storage fluid undergoes the first heat exchange, it reaches the second heat storage layer (14) along the first direction and then undergoes a second heat exchange with the second heat storage medium. After the secondary heat exchange, the heat storage fluid reaches the third heat storage layer (15) along the first direction and undergoes three heat exchanges with the third heat storage medium. The heat storage fluid after the three heat exchanges is discharged from the heat storage tank (1) through the second opening (12) along the first direction to complete the heat storage; The heat storage fluid is any one of molten salt, heat transfer oil, quartz sand, air, nitrogen, and argon. The first heat storage medium is any one of cast iron, stainless steel, alumina, magnesium oxide, zirconium oxide and phase change material with a particle size of <2 cm; The second heat storage medium is any one of sand, quartz, cement, concrete and graphite with a particle size of <2 cm; The third heat storage medium is any one of cast iron, stainless steel, alumina, magnesium oxide, zirconium oxide, and phase change materials with a particle size of <2 cm.

8. The high-temperature thermal storage method comprising multiple layers of different materials according to claim 7, characterized in that, The first thermal storage medium and the third thermal storage medium are phase change materials; The phase change material is composed of a metallic element coated with particles; The particle coating is composed of hollow particles made of any one of aluminum silicate, calcium silicate, polyimide, alumina, and zirconium oxide. The metallic element is any one of iron, aluminum, tin, magnesium, and copper.

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