Sensible heat and phase change heat storage coupled energy storage system and method thereof

Abstract

The invention provides a sensible heat and phase change heat storage coupled energy storage system and method. The energy storage system comprises a heat storage tank and a heat preservation layer. A first gas transmission port is formed in the first end of the heat storage tank, a second gas transmission port is formed in the second end, opposite to the first end, of the heat storage tank, and the heat storage tank is filled with a heat storage medium; a phase change area and a heat preservation area are arranged between the heat storage tank and the heat preservation layer in the first direction. The phase change area and the heat preservation area are separated through a partition plate, and the heat preservation area and the heat preservation layer are separated through a partition plate. The phase change area is filled with a phase change material, and the heat preservation area is filled with a porous medium. By additionally arranging the phase change area and the heat preservation area, the heat storage efficiency of the energy storage system is improved, the heat storage temperature is increased, the use amount of heat preservation materials is reduced, and therefore the heat storage cost is reduced. Meanwhile, the heat preservation effect is achieved through the change of the structure of the energy storage system in cooperation with the phase-change material and the porous material, the requirement for the performance of the heat preservation material can be lowered, and therefore the application variety of the heat preservation material is widened.

Description

Technical Field

[0001] The present application relates to the field of thermal energy storage technology, and more specifically, to an energy storage system and method thereof that couples sensible heat and phase change heat storage. Background Art

[0002] Renewable energy is considered a promising alternative to traditional fossil fuels in the future. Renewable energy sources, such as solar and wind, are considered to have enormous potential due to their abundant resources, environmental friendliness, and ease of access. However, the inherent intermittent nature of these energy sources creates a mismatch between supply and demand, necessitating the use of energy storage technologies to effectively dispatch renewable energy.

[0003] Among numerous energy storage technologies, thermal energy storage has attracted widespread attention for its high cost-effectiveness, energy conversion efficiency, and flexible storage capacity. However, as the storage temperature of thermal storage tanks increases, the required insulation thickness becomes significantly thicker to minimize heat loss, significantly increasing storage costs. Furthermore, as the storage temperature increases, the available insulation materials decrease, hindering effective thermal insulation. Summary of the Invention

[0004] To address the above-mentioned issues, this application provides an energy storage system and method that couples sensible heat and phase change heat storage. By adding phase change zones and insulation zones within the energy storage system, the system's own heat storage efficiency is improved, the heat storage temperature is increased, and the amount of insulation material used is reduced, thereby reducing heat storage costs. Furthermore, by changing the energy storage system's structure, in combination with phase change materials and porous materials, a more efficient insulation effect is achieved, thereby reducing the performance requirements for insulation materials and broadening the range of applicable insulation materials.

[0005] In a first aspect, the present application provides an energy storage system that couples sensible heat and phase change heat storage, the energy storage system comprising: a heat storage tank (1) and an insulation layer (2); The first end (11) of the heat storage tank (1) is provided with a first gas delivery port (111), and the second end (12) of the heat storage tank (1) opposite to the first end (11) is provided with a second gas delivery port (121), and the interior of the heat storage tank (1) is filled with a heat storage medium; A phase change zone (3) and a heat preservation zone (4) are provided between the heat storage tank (1) and the heat preservation layer (2) along a first direction, and the phase change zone (3) and the heat preservation zone (4), as well as the heat preservation zone (4) and the heat preservation layer (2) are separated by partitions (5); The phase change zone (3) is filled with a phase change material, and the heat preservation zone (4) is filled with a porous medium.

[0006] Furthermore, a plurality of storage pipes (13) are provided inside the heat storage tank (1), and the storage pipes (13) are used to store the phase change material; The storage pipes (13) are arranged in the heat storage tank (1) at intervals along a second direction perpendicular to the first direction, and the heat storage medium is located between two adjacent storage pipes (13).

[0007] Furthermore, the size of the storage pipe (13) along the first direction is 0.5 m to 5 m.

[0008] Furthermore, the ratio of the total filling amount of the phase change material to the total filling amount of the heat storage medium is (1-1.5):1.

[0009] Furthermore, the distance between the phase change material and the partition (5) between the phase change zone (3) and the heat preservation zone (4) is 0.5 m to 2 m.

[0010] Furthermore, a third gas delivery port (41) and a fourth gas delivery port (42) are respectively provided at two opposite ends of the heat preservation zone (4), and the third gas delivery port (41) and the fourth gas delivery port (42) are used to deliver gas at room temperature.

[0011] Furthermore, the porous medium accounts for 30% to 50% of the total volume of the interior of the insulation zone (4).

[0012] Furthermore, the energy storage system further includes an air distribution plate (6); The air distribution plates (6) are respectively arranged at the first end (11) and the second end (12); The air distribution plate (6) is provided with a plurality of vent holes (61), and the vent holes (61) are connected to the first air delivery port (111) and the second air delivery port (121).

[0013] Furthermore, the total volume of the plurality of ventilation holes (61) accounts for 5% to 15% of the total volume of the air distribution plate (6).

[0014] In a second aspect, the present application provides an energy storage method for coupling sensible heat and phase change heat storage, the method being applicable to the energy storage system for coupling sensible heat and phase change heat storage as described in the first aspect, the method comprising: A heat storage gas having a temperature of 500° C. to 1500° C. is fed into a heat storage tank (1) through a first gas delivery port (111); the heat storage gas transfers heat to a heat storage medium and then is discharged from the heat storage tank (1) through a second gas delivery port (121); The heat storage medium transfers heat to the phase change zone (3) through the heat storage tank (1), exchanges heat with the phase change material, and the phase change material melts due to the heat, and the temperature of the phase change zone (3) is maintained at the melting point temperature of the phase change material; The melted phase change material transfers part of the heat to the heat preservation zone (4) through the partition (5), and the porous medium absorbs the heat and maintains the temperature of the heat preservation zone (4) at 100°C to 250°C; The heat-insulating layer (2) is used to prevent the heat inside the heat-insulating zone (4) from being transferred to the outside, thereby maintaining heat; Wherein, the heat storage gas is any one of air, nitrogen and argon; The heat storage medium is any one of alumina particles, quartz sand particles and cement particles; The phase change material is any one of tin, aluminum and iron; The porous medium is aluminum oxide or magnesium oxide.

[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. The present application provides an energy storage system that couples sensible heat and phase change heat storage. By filling a heat storage medium in a heat storage tank, providing a phase change zone, and filling the phase change zone with a phase change material, efficient energy storage is achieved by coupling sensible heat and phase change heat storage. The phase change material can absorb or release a large amount of heat during the phase change process, and the heat storage medium further increases the energy storage capacity through sensible heat storage, so that the device can efficiently store heat within different temperature ranges, thereby improving energy storage efficiency and flexibility. In addition, by providing a heat preservation zone and filling the heat preservation zone with a porous medium, heat loss can be further reduced. In particular, when the heat storage temperature is high, heat can be effectively retained, reducing the heat loss of the heat storage tank. The phase change zone and the heat preservation zone structure provided enable the energy storage system itself to achieve a high heat preservation effect, thereby reducing the amount of heat preservation material used, reducing the thickness of the heat preservation material, and greatly reducing the heat storage cost. In addition, by providing the phase change zone and the heat preservation zone, the dependence on the heat preservation material can be reduced, and a wider variety of heat preservation materials can be selected, increasing the flexibility of the heat preservation material selection. 2. The present application provides an energy storage method that couples sensible heat and phase change heat storage. By coupling sensible heat and phase change heat storage, the method enables the heat storage gas to transfer heat to the heat storage medium at a high temperature of 500°C to 1500°C, thereby realizing efficient thermal energy storage; and then the heat is further transferred to the phase change material. After the phase change material is heated and melted, it can maintain the melting point temperature for a long time, so that the temperature of the phase change zone remains constant, while absorbing a large amount of heat, further improving the energy storage density and efficiency, and helping to reduce the outward transfer of heat. The melted phase change material transfers a small amount of heat to the porous medium through the partition. The porous medium further realizes the heat absorption function, preserves the heat, maintains the temperature of the insulation zone between 20°C and 30°C, further reduces the heat dissipated to the outside, and greatly reduces the heat transferred to the insulation material through the partition, thereby reducing the requirement for the thickness of the insulation material and reducing the heat storage cost. Since the insulation material has a low temperature at which the heat is lost, the range of insulation materials is wider. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 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.

[0017] Figure 1 A schematic diagram of the structure of the energy storage system coupled with sensible heat and phase change heat storage proposed in an embodiment of the present application is shown; Figure 2 A schematic cross-sectional structure diagram of a heat storage tank and a phase change zone proposed in an embodiment of the present application is shown; Figure 3 A schematic structural diagram of the air distribution plate proposed in an embodiment of the present application is shown; Figure 4 A flow chart of the energy storage method of coupling sensible heat and phase change heat storage proposed in an embodiment of the present application is shown; Figure 5 A flow chart of a heat release method coupled with sensible heat and phase change heat storage proposed in an embodiment of the present application is shown; Figure 6 The energy storage system used in Comparative Example 1 of the present application is shown.

[0018] Description of reference numerals: 1. Hot storage tank; 11. First end; 111. First gas outlet; 12. Second end; 121. Second gas outlet; 13. Storage pipe; 14. Cavity; 2. Insulation layer; 3. Phase change zone; 4. Insulation zone; 41. Third gas outlet; 42. Fourth gas outlet; 5. Partition; 6. Air distribution plate; 61. Ventilation hole. DETAILED DESCRIPTION

[0019] 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.

[0020] 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.

[0021] Renewable energy is considered a promising alternative to traditional fossil fuels in the future. Renewable energy sources, such as solar and wind, are considered to have enormous potential due to their abundant resources, environmental friendliness, and ease of access. However, the inherent intermittent nature of these energy sources creates a mismatch between supply and demand, necessitating the use of energy storage technologies to effectively dispatch renewable energy.

[0022] Among various energy storage technologies, thermal energy storage has attracted widespread attention due to its high cost-effectiveness, energy conversion efficiency, and flexible storage capacity. The principles of thermal energy storage technology mainly involve the first and second laws of thermodynamics. Through certain technical means, thermal energy is converted into other forms of energy for storage and then converted back into thermal energy for utilization when needed. Among them, sensible heat storage is the main form of thermal energy storage technology: Sensible heat storage: This method uses temperature differences between materials to store thermal energy. During sensible heat storage, heat is directly stored in the material's temperature. When needed, the stored heat is released through heat exchange. This method is relatively simple, but has a low storage density and is prone to energy loss during storage.

[0023] In addition to the above energy storage methods, thermal storage tanks are often wrapped in insulation. However, as the storage temperatures of thermal storage tanks continue to rise, the required thickness of insulation material becomes significantly thicker to minimize heat loss. Furthermore, as the storage temperature increases, the available insulation material options decrease, resulting in higher insulation costs.

[0024] In order to solve the problems existing in the related art, this application provides an energy storage system that couples sensible heat and phase change heat storage, see Figure 1 , the system comprises: a heat storage tank 1 and an insulation layer 2; The first end 11 of the heat storage tank 1 is provided with a first gas delivery port 111, and the second end 12 of the heat storage tank 1 opposite to the first end 11 is provided with a second gas delivery port 121. The heat storage tank 1 is filled with a heat storage medium. A phase change zone 3 and a heat preservation zone 4 are provided between the heat storage tank 1 and the heat preservation layer 2 along a first direction, and the phase change zone 3 and the heat preservation zone 4, and the heat preservation zone 4 and the heat preservation layer 2 are separated by partitions 5; The phase change zone 3 is filled with a phase change material, and the heat preservation zone 4 is filled with a porous medium.

[0025] It should be noted that the heat storage tank 1 is composed of a sealed tank body made of high temperature resistant and corrosion resistant materials, such as stainless steel, carbon steel, etc. The cross-sectional shape of the heat storage tank 1 is rectangular, circular, etc.; In one case, the first end 11 is the upper end of the heat storage tank 1 and the second end 12 is the lower end of the heat storage tank 1; in another case, the first end 11 is the left end of the heat storage tank 1 and the second end 12 is the right end of the heat storage tank 1; The first direction x is a direction extending along the width of the heat storage tank 1; The insulation layer 2 is a layered structure composed of insulation material of a certain thickness. The insulation layer 2 is arranged along a first direction outside the partition 5 provided in the insulation area 4; In the embodiment of the present application, the thickness of the insulation layer 2 can be 0.5 m~1 m. In specific implementation, the thickness of the insulation layer 2 can be set according to the size of the heat storage tank 1; The phase change zone 3 and the heat preservation zone 4 are both sealed spaces, and the two ends of the adjacent partitions 5 are connected. The two ends of the partition 5 between the phase change zone 3 and the heat preservation zone 4 are also connected to the outer wall of the heat storage tank 1, forming a sealed energy storage system; The material of the partition 5 can be any one of ceramic material, refractory brick, high temperature alloy and thermal insulation fiber material, which needs to be non-melting at 2000°C and non-reactive with the phase change material and thermal insulation material; The heat storage medium is any one of alumina particles, quartz sand particles and cement particles; The phase change material is a metal element, and the metal element is any one of tin, aluminum and iron; The porous medium is aluminum oxide or magnesium oxide.

[0026] In specific implementation, the heat storage gas first flows downward through the first gas inlet 111 into the heat storage tank 1, exchanging heat with the heat storage medium within the tank 1 and storing the heat there. The heat storage medium then transfers heat to the phase change zone 3 through the outer wall of the tank 1, heating the phase change material until it reaches its melting point and begins to melt. As the phase change material gradually melts, the temperature within the phase change zone 3 remains constant at its melting point, absorbing and storing the heat dissipated from the tank 1. The phase change material then transfers a small amount of heat through the partition 5 to the insulation zone 4. The porous medium in the insulation zone 4 absorbs the heat and maintains the heat, further reducing the amount of heat that diffuses into the insulation layer 2. This significantly reduces the amount of heat that the insulation layer 2 needs to block from diffusing outward. In practice, this can reduce the thickness of the insulation layer 2, lowering heat storage costs. Furthermore, since the amount of heat that diffuses into the insulation layer 2 is relatively small, a wider range of insulation layer options are available, further facilitating efficient insulation even with a thinner insulation layer 2.

[0027] During heat release, the cold gas is fed upward through the second gas inlet 121 into the heat storage tank 1, where it undergoes heat exchange with the heat storage medium. The cold gas absorbs heat and heats up. After the heat storage medium's temperature drops, it absorbs heat from the phase change material through the heat storage tank 1. Once the phase change material's temperature drops to its freezing point, it begins to condense. Heat release is complete once the melted phase change material has completely condensed.

[0028] For specific implementation, see Figure 1 The dimensions of the first end 11 and the second end 12 of the heat storage tank 1 in the first direction gradually decrease along the length of the heat storage tank 1. Specifically, the dimensions of the first gas inlet 111 and the second gas inlet 121 in the first direction are smaller than the dimensions of the heat storage tank 1 in the first direction. This reduces the surface area at both ends of the heat storage tank 1. Since heat loss is proportional to surface area, the tapered design of the heat storage tank 1 helps reduce heat loss, thereby improving the energy efficiency of the heat storage tank 1 and enabling more thermal energy to be effectively stored and utilized, thereby enhancing the thermal efficiency of the entire energy storage system.

[0029] As the dimensions of the heat storage tank 1 at both ends gradually decrease, the thermal expansion of the heat storage tank 1 in these areas will also decrease accordingly, helping to alleviate the thermal stress generated inside the heat storage tank 1 under high temperature conditions, thereby improving the structural stability of the heat storage tank 1. It also reduces the deformation of the heat storage tank 1 under temperature changes to a certain extent, further enhancing the reliability of its overall structure.

[0030] In some embodiments, see Figure 2 , a plurality of storage pipes 13 are provided inside the heat storage tank 1, and the storage pipes 13 are used to store the phase change material; The storage pipes 13 are arranged in the heat storage tank 1 at intervals along a second direction perpendicular to the first direction, and the heat storage medium is located between two adjacent storage pipes 13 .

[0031] It should be noted that the cross-sectional shape of the storage tube 13 can be circular, rectangular, diamond-shaped, etc. The number of the storage pipes 13 is not specifically limited in the embodiment of the present application. In specific implementation, the storage pipes 13 are arranged at intervals along the second direction in the heat storage tank 1 according to the size of the heat storage tank 1. The connection between the storage pipe 13 and the heat storage tank 1 can be welding, threaded connection, riveting, etc., which is not specifically limited in the embodiment of the present application; The material of the storage tube 13 can be stainless steel, corundum or carbon fiber composite material, etc. The distance between two adjacent storage pipes 13 is not greater than 0.5 m. In specific implementation, the distance between the two storage pipes 13 is reasonably set according to the size of the heat storage tank 1; The second direction y is a direction extending along the length direction of the heat storage tank 1 .

[0032] In practice, during the heat storage process, the phase change material is filled into the storage tubes 13, and the heat storage medium is filled between two adjacent storage tubes 13, as well as between the storage tubes 13 and the inner wall of the heat storage tank 1. During the heat storage process, the heat storage medium and the heat storage gas transfer heat directly to the phase change material through the storage tubes 13, causing the phase change material to melt. The melted phase change material is then stored in the storage tubes 13, preventing contamination of the heat storage medium.

[0033] By providing a storage tube 13, the heat storage gas can transfer heat directly to the phase change material through the tube 13, further reducing heat loss. During the melting process, the phase change material remains at its melting point. The heat transferred by the heat storage gas is stored by both the phase change heat of the phase change metal and the heat storage medium, significantly increasing the energy density of the heat stored in the heat storage tank 1 and improving the heat quality.

[0034] In some embodiments, the phase change material occupies 60% to 80% of the volume of the storage tube 13. Avoiding filling the storage tube 13 with the phase change material provides sufficient space for the phase change material to melt and expand, thereby reducing safety hazards during the energy storage process.

[0035] In some embodiments, see Figure 2 The size of the storage pipe 13 along the first direction is 0.5 m to 5 m.

[0036] It should be noted that the dimension of the material storage tube 13 along the first direction is the diameter of the material storage tube 13 in the first direction.

[0037] In a specific implementation, the size of the storage pipe 13 along the second direction can be 0.5 m, 1 m, 1.5 m, 2 m, 2.5 m, 3 m, 3.5 m, 4 m, 4.5 m or 5 m.

[0038] By setting the size of the storage pipe 13, it is helpful to arrange the space inside the heat storage tank 1 more reasonably, ensuring that a sufficient amount of heat storage medium is placed, and avoiding the problems of reduced heat energy transfer efficiency and insufficient structural strength caused by the storage pipe 13 being too large. It helps to optimize the overall size and weight of the heat storage tank 1 and reduce manufacturing costs and transportation difficulties.

[0039] In some embodiments, the ratio of the total filling amount of the phase change material to the total filling amount of the heat storage medium is (1-1.5):1.

[0040] In a specific implementation, the ratio of the total filling amount of the variable material to the total filling amount of the heat storage medium can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1.

[0041] By adjusting the filling ratio of the phase change material to the heat storage medium, the interior of the heat storage tank 1 can fully utilize the phase change energy storage properties of the phase change material and the sensible heat storage properties of the heat storage medium. The heat storage medium can absorb and store this heat, while the phase change material can absorb or release a large amount of heat during the phase change process, thereby improving the thermal energy storage density and release efficiency of the entire heat storage tank 1.

[0042] Combined with the spaced arrangement of the storage tubes 13 along the second direction, and a reasonable ratio of the phase change material to the heat storage medium, this facilitates uniform distribution and transfer of heat energy within the heat storage tank 1. During heat release, heat can be more efficiently transferred from the phase change material in the storage tubes 13 to the heat storage medium, and then transferred to the cold gas through the heat storage medium. This improves the uniformity of heat transfer from the heat storage tank 1 and reduces heat loss during the transfer process.

[0043] In some embodiments, see Figure 1 The distance between the phase change material and the partition 5 between the phase change zone 3 and the heat preservation zone 4 is 0.5 m~2 m.

[0044] It should be noted that the distance is the vertical distance from the phase change material to the side wall of the partition 5 along the first direction.

[0045] In a specific implementation, the distance between the phase change material and the partition 5 between the phase change zone 3 and the heat preservation zone 4 can be 0.5 m, 1 m, 1.5 m or 2 m.

[0046] Since the phase change material expands when heated and melted, sufficient space is left between the phase change material and the separator 5 by setting a certain distance to prevent the phase change material from overflowing the phase change region 3 or deforming the separator 5 after melting and expanding, thereby helping to maintain the stability of the energy storage system structure.

[0047] In some embodiments, see Figure 1The insulation zone 4 has two opposite ends respectively provided with a third gas delivery port 41 and a fourth gas delivery port 42 , and the third gas delivery port 41 and the fourth gas delivery port 42 are used to deliver room temperature gas.

[0048] It should be noted that, in one case, the third gas port 41 is arranged at the upper end of the insulation zone 4, and the fourth gas port 42 is arranged at the lower end of the insulation zone 4; in another case, the third gas port 41 is arranged at the left end of the insulation zone 4, and the fourth gas port 42 is arranged at the right end of the insulation zone 4; the third gas port 41 and the first gas port 111 are arranged in parallel on the same axis, and the fourth gas port 42 and the second gas port 121 are arranged in parallel on the same axis.

[0049] Normal temperature gas can be normal temperature air, nitrogen or argon, etc.; The temperature of the ambient gas is set to 20 ℃ ~ 30 ℃.

[0050] By providing a third gas inlet 41 and a fourth gas inlet 42 in the insulation zone 4, ambient temperature gas is delivered into the insulation zone 4 through the third gas inlet 41. The ambient temperature gas then flows downward and contacts the porous medium, exchanging heat. This helps maintain the porous medium's temperature between 20°C and 30°C, thereby consistently maintaining the temperature of the insulation zone 4 between 20°C and 30°C. This prevents the porous medium from absorbing too much heat and causing the temperature of the insulation zone 4 to rise. The heat-exchanged gas then flows downward through the fourth gas inlet 42 and out of the insulation zone 4. New ambient temperature gas is then discharged into the insulation zone 4 through the third gas inlet 41, forming a cycle that ensures the temperature of the insulation zone 4 remains within a specified range.

[0051] In some embodiments, see Figure 1 , the porous medium accounts for 30% to 50% of the total volume inside the insulation zone 4.

[0052] In a specific implementation, the porous medium occupies 30%, 35%, 45% or 50% of the total volume of the interior of the insulation zone 4.

[0053] By setting the volume of the porous medium, on the one hand, the temperature of the heat preservation zone 4 is ensured to be constant, and on the other hand, the amount of porous medium used is reduced, thereby saving energy storage costs.

[0054] In some embodiments, see Figure 2 , the system further includes an air distribution plate 6; The air distribution plates 6 are respectively arranged at the first end 11 and the second end 12; The air distribution plate 6 is provided with a plurality of vent holes 61 , and the vent holes 61 are connected to the first air delivery port 111 and the second air delivery port 121 .

[0055] It should be noted that the cross-sectional shape of the air distribution plate 6 can be rectangular, circular, elliptical, etc. The shape of the air distribution plate 6 is adapted to the heat storage tank 1; The size of the air distribution plate 6 along the first direction is larger than the size of the first air delivery port 111 and the second air delivery port 121 in the first direction; The material of the air distribution plate 6 is not specifically limited in this embodiment. However, the material of the air distribution plate 6 must have a melting point below 2000°C to ensure that it does not melt during the heat storage and release process. In addition, the air distribution plate 6 must be physically and chemically stable and not chemically react with the heat storage gas or heat storage medium.

[0056] During specific implementation, by providing the structure of the air distribution plate 6 and arranging the air distribution plate 6 at the first end 11 and the second end 12 of the heat storage tank 1, it is possible to evenly distribute and guide the flow of the heat storage gas through the multiple air vents 61 provided thereon, making the flow of the heat storage gas in the heat storage tank 1 more uniform. The multiple air vents 61 are connected to the first gas transmission port 111 and the second gas transmission port 121, ensuring that the heat storage gas can smoothly enter and exit the heat storage tank 1, helping to increase the contact area and contact time between the heat storage gas and the heat storage medium, thereby improving the heat exchange efficiency. Furthermore, by evenly distributing the air vents 61 on the air distribution plate 6, it is helpful to reduce local overheating or cooling in the heat storage tank 1, ensuring a more uniform temperature distribution throughout the energy storage system. At the same time, the air distribution plate 6 can also serve as an additional barrier to prevent the heat storage medium from moving or accumulating due to uneven gas flow, further enhancing the stability and safety of the system.

[0057] For specific implementation, see Figure 2 The air distribution plates 6 are installed on the inner wall of the heat storage tank 1 near the first gas outlet 111 and the second gas outlet 121. The two ends of the storage pipe 13 correspond to the two air distribution plates 6 one by one and are fixedly connected. The heat storage medium is filled between the two air distribution plates 6 to limit the movement of the heat storage medium and ensure the stability of heat transfer.

[0058] For specific implementation, see Figure 2 A cavity 14 is formed between the air distribution plate 6 and the first and second air delivery ports 111, 121. This cavity 14 provides an additional insulating layer, reducing the amount of heat transferred directly from the walls of the heat storage tank 1 to the external environment. This helps further reduce heat loss and improve the thermal insulation performance of the heat storage tank 1. The insulating effect of cavity 14 is particularly significant under high-temperature conditions, helping to maintain the high temperature of the heat storage medium and extend the storage time of thermal energy.

[0059] The presence of cavity 14 also changes the heat transfer path within heat storage tank 1. During this transfer process, heat must first pass through the heat storage medium, then through the insulating effect of cavity 14, before finally dissipating through the walls of heat storage tank 1 to the external environment. This extended path helps slow the rate of heat loss, allowing heat to be retained in the heat storage medium longer, thereby improving the thermal energy utilization efficiency of heat storage tank 1.

[0060] In some embodiments, see Figure 3 The total volume of the plurality of ventilation holes 61 accounts for 5% to 15% of the total volume of the air distribution plate 6.

[0061] It should be noted that the total volume of the plurality of vents 61 accounts for 5% to 15% of the total volume of the air distribution plate 6, which means that the porosity of the air distribution plate 6 is 5%-15%.

[0062] In practice, by setting a specific ratio between the total volume of the multiple vents 61 and the total volume of the air distribution plate 6, the heat storage gas is evenly distributed across the air distribution plate 6. The number of vents 61 helps balance the flow rate and pressure of the gas, preventing localized overheating or cooling, thereby improving the efficiency and uniformity of heat exchange. Within a porosity range of 5% to 15%, the vents 61 provide sufficient channels for the flow of heat storage gas and cold gas, promoting effective heat exchange.

[0063] Second, see Figure 4 The present application provides an energy storage method that couples sensible heat and phase change heat storage, the method comprising: Step S1: delivering heat storage gas at a temperature of 500°C to 1500°C into the heat storage tank 1 through the first gas delivery port 111. The heat storage gas transfers heat to the heat storage medium and then is discharged from the heat storage tank 1 through the second gas delivery port 121. Step S2: The heat storage medium transfers heat to the phase change zone 3 through the heat storage tank 1, exchanges heat with the phase change material, and the phase change material melts under the heat, and the temperature of the phase change zone 3 is maintained at the melting point temperature of the phase change material; Step S3: The melted phase change material transfers part of the heat to the insulation zone 4 through the partition 5, and the porous medium absorbs the heat and maintains the temperature of the insulation zone 4 at 20°C to 30°C; Step S4: The heat-insulating layer 2 is used to prevent the heat inside the heat-insulating area 4 from being transferred to the outside, thereby maintaining heat; Wherein, the heat storage gas is any one of air, nitrogen and argon; The heat storage medium is any one of alumina particles, quartz sand particles and cement particles; The phase change material is any one of tin, aluminum and iron; The porous medium is aluminum oxide or magnesium oxide.

[0064] It should be noted that in the energy storage system, a heat storage gas (such as air, nitrogen, or argon) enters through the first gas inlet 111 of the heat storage tank 1 and exchanges heat with the heat storage medium (such as alumina particles, quartz sand particles, or cement particles). During this heat storage process, the heat of the heat storage gas is transferred to the heat storage medium primarily through convection and radiation. Among them, convection refers to the heat transfer caused by temperature difference when the heat storage gas flows in the heat storage tank 1; while radiation refers to the heat transfer from the high-temperature object (heat storage gas) to the low-temperature object (heat storage medium) in the form of electromagnetic waves.

[0065] Factors that affect heat storage efficiency include: (1) the flow rate of the heat storage gas. The higher the flow rate, the better the convective heat transfer effect; (2) the physical properties of the heat storage medium, such as particle size, shape, thermal conductivity and specific heat capacity, which directly affect the efficiency and effect of heat transfer.

[0066] Based on the above, the flow rate of the heat storage gas in the embodiment of the present application can be set to 0.2-15 m / s, which can achieve a high heat exchange effect and preserve the heat in the heat storage tank 1 as much as possible.

[0067] The heat storage medium selected in the embodiment of the present application is a granular material with a particle size of less than 10 cm, which can greatly increase the heat exchange area. The granular material has a melting point of less than 2000°C, can be used as a high-temperature heat storage material, has good physical and chemical stability, and does not react with the heat storage gas. The phase change material selected in the embodiment of the present application is a metal element with a melting point between 230°C and 1500°C; When the temperature of the heat storage gas delivered by the first gas delivery port 111 is 500°C to 800°C, metal tin or metal aluminum is used as the phase change material to fill the phase change zone 3; when the temperature of the heat storage gas delivered by the first gas delivery port 111 is 1000°C to 1500°C, metal iron is used as the phase change material to fill the phase change zone 3; The insulation layer 2 selected in the embodiment of the present application is composed of conventional insulation materials. This insulation material has low thermal conductivity and can effectively keep heat in different environments. The melting point of this insulation material is below 1000°C, which greatly broadens the selection of insulation materials. The heat storage gas selected in the embodiment of the present application is air, nitrogen or argon; when the heat storage medium reacts with air, nitrogen or argon is selected as the heat storage gas; the heat storage temperature of the heat storage gas can be selected from 250°C to 1500°C. During specific implementation, the heat storage inlet temperature can be adjusted according to needs.

[0068] The porous media selected in this embodiment of the application: aluminum oxide or magnesium oxide not only has good thermal conductivity, can quickly absorb heat from the phase change material, but also has a high specific heat capacity. The pore structure of the porous medium increases its surface area, which is conducive to the transfer and storage of heat.

[0069] The higher the porosity, the larger the surface area of ​​the porous medium, which is more conducive to heat transfer and storage. The porosity of the aluminum oxide and magnesium oxide selected in the embodiment of the present application is about 0.4.

[0070] The insulation layer 2 selected in the embodiment of the present application needs to be resistant to high temperatures and have low thermal conductivity. Ceramic fibers, aerogels or multi-layer composite materials, etc. can be selected to effectively block heat transfer and reduce heat loss.

[0071] Compared to traditional single-energy storage methods, the energy storage method proposed in this application, which combines sensible heat and phase change heat storage, can fully utilize the temperature differences of the heat storage medium and the latent heat of the phase change material, thereby significantly improving energy storage density. Furthermore, because the phase change energy storage process occurs at a relatively constant temperature, i.e., the melting point of the phase change material, energy loss is relatively small, improving energy storage efficiency.

[0072] By introducing a porous medium, heat loss inside the heat storage tank 1 and the phase change zone 3 is effectively reduced. The porous medium can absorb and store heat from the phase change material, while maintaining the insulation zone 4 within a relatively low temperature range (20°C to 30°C), reducing energy loss caused by heat conduction and radiation. The insulation layer 2 further blocks the transfer of heat from the insulation zone 4 to the external environment, ensuring the long-term energy storage stability and efficiency of the energy storage system. By providing the phase change zone 3 and the insulation zone 4, even at high heat storage temperatures, the thickness and type of insulation materials can be effectively reduced, reducing the cost of the insulation layer 2 and improving the economy and feasibility of the energy storage system.

[0073] For specific implementation, see Figure 5 , shows a flow chart of the heat release method of coupling sensible heat and phase change heat storage proposed in an embodiment of the present application, and the specific processing steps include: Step S11: The cold gas is transported upwards into the heat storage tank 1 along the second gas transmission port 121. The heat storage medium transfers heat to the cold air. After the cold air absorbs the heat, it is discharged from the heat storage tank 1 along the first gas transmission port 111. Step S12: wherein the phase change material transfers heat to the cold air in the heat storage tank 1 through the heat storage tank 1, and the phase change material releases heat and solidifies, so that the temperature of the phase change zone 3 is maintained at the phase change point temperature until all the melted phase change materials are solidified, completing the heat release process.

[0074] Since the energy storage system provided in the embodiment of the present application can store higher temperatures, it also releases more heat when releasing heat, making the temperature of the cold gas higher and achieving efficient energy storage.

[0075] In order to enable those skilled in the art to understand the present application more clearly, the energy storage system and method for coupling sensible heat and phase change heat storage described in the present application are now described in detail through the following embodiments.

[0076] Example 1 application Figure 1 The energy storage system shown couples sensible heat and phase change heat storage.

[0077] 1. Nitrogen at a temperature of 1000°C is delivered to the cavity 14 through the first gas delivery port 111, and then flows downward into the heat storage tank 1 through the vents 61 on the air distribution plate 6 at the first end 11 of the heat storage tank 1. After the nitrogen transfers heat to the alumina particles, it flows downward to the air distribution plate 6 at the second end 12, and is discharged from the heat storage tank 1 in sequence through the vents 61 on the air distribution plate 6 at the second end 12, the cavity 14, and the second gas delivery port 121. 2. The alumina particles transfer the absorbed heat to the phase change zone 3 through the heat storage tank 1. The metallic iron in the phase change zone 3 is melted by the heat, and the temperature of the phase change zone 3 is kept at the melting point of the metallic iron. 3. The molten iron transfers some of its heat to the insulation zone 4 through the partition 5. The porous magnesium oxide in the insulation zone 4 absorbs the heat. At the same time, room temperature air is transported downward through the third air inlet 41 to the insulation zone 4 and then discharged downward through the fourth air inlet 42. Together, the temperature of the insulation zone 4 is maintained at 25°C. 4. The insulation layer 2 is used to prevent the heat inside the insulation zone 4 from being transferred to the outside and to perform insulation treatment until all the nitrogen is stored.

[0078] Example 2 The main differences between Example 2 and Example 1 are the different temperatures of the heat storage gas and the different phase change materials.

[0079] 1. Air at a temperature of 650°C is delivered to the cavity 14 through the first air delivery port 111, and then flows downward into the heat storage tank 1 through the air vents 61 on the air distribution plate 6 at the first end 11 of the heat storage tank 1. After the air transfers heat to the quartz sand particles, it reaches the air distribution plate 6 at the second end 12 and is discharged from the heat storage tank 1 in sequence through the air vents 61 on the air distribution plate 6 at the second end 12, the cavity 14, and the second air delivery port 121. 2. The quartz sand particles transfer the absorbed heat to the phase change zone 3 through the heat storage tank 1. The metal tin in the phase change zone 3 is melted by the heat, and the temperature of the phase change zone 3 is kept at the melting point of the metal tin; 3. The molten tin metal transfers some of its heat through the partition 5 to the insulation zone 4. The porous alumina in the insulation zone 4 absorbs the heat and simultaneously delivers room temperature air downward through the third air delivery port 41 to the insulation zone 4. The air is then discharged downward through the fourth air delivery port 42 to maintain the temperature of the insulation zone 4 at 25°C. 4. The insulation layer 2 is used to prevent the heat inside the insulation area 4 from being transferred to the outside and to perform insulation treatment until all the air has completed energy storage.

[0080] Example 3 The difference between Example 3 and Example 1 is that the heat storage tank 1 used in Example 3 is provided with a storage pipe 13 .

[0081] 1. Nitrogen at a temperature of 1000°C is delivered into the cavity 14 through the first gas delivery port 111. The nitrogen then flows downward into the heat storage tank 1 through the air vents 61 on the air distribution plate 6 at the first end 11 of the heat storage tank 1. The nitrogen transfers heat to the alumina particles and the metallic iron in the storage tube 13. The nitrogen then flows downward to the air distribution plate 6 at the second end 12. The nitrogen then flows out of the heat storage tank 1 through the air vents 61 on the air distribution plate 6 at the second end 12, the cavity 14, and the second gas delivery port 121. The metallic iron is melted by the heat, and the temperature in the storage tube 13 is maintained at the melting point of the metallic iron. 2. The alumina particles transfer the absorbed heat to the phase change zone 3 through the heat storage tank 1. The metallic iron in the phase change zone 3 is melted by the heat, and the temperature of the phase change zone 3 is kept at the melting point of the metallic iron. 3. The molten iron transfers some of its heat to the insulation zone 4 through the partition 5. The porous magnesium oxide in the insulation zone 4 absorbs the heat. At the same time, room temperature air is transported downward through the third air inlet 41 to the insulation zone 4 and then discharged downward through the fourth air inlet 42. Together, the temperature of the insulation zone 4 is maintained at 25°C. 4. The insulation layer 2 is used to prevent the heat inside the insulation zone 4 from being transferred to the outside and to perform insulation treatment until all the nitrogen is stored.

[0082] Example 4 The difference between Example 4 and Example 1 is that Example 3 further includes a heat release step, specifically: 1. Nitrogen at a temperature of 1000°C is delivered to the cavity 14 through the first gas delivery port 111, and then flows downward into the heat storage tank 1 through the vents 61 on the air distribution plate 6 at the first end 11 of the heat storage tank 1. After the nitrogen transfers heat to the alumina particles, it flows downward to the air distribution plate 6 at the second end 12, and is discharged from the heat storage tank 1 in sequence through the vents 61 on the air distribution plate 6 at the second end 12, the cavity 14, and the second gas delivery port 121. 2. The alumina particles transfer the absorbed heat to the phase change zone 3 through the heat storage tank 1. The metallic iron in the phase change zone 3 is melted by the heat, and the temperature of the phase change zone 3 is kept at the melting point of the metallic iron. 3. The molten iron transfers some of its heat to the insulation zone 4 through the partition 5. The porous magnesium oxide in the insulation zone 4 absorbs the heat. At the same time, room temperature air is transported downward through the third air inlet 41 to the insulation zone 4 and then discharged downward through the fourth air inlet 42. Together, the temperature of the insulation zone 4 is maintained at 25°C. 4. The insulation layer 2 is used to prevent the heat inside the insulation zone 4 from being transferred to the outside, and to perform insulation treatment until all the nitrogen is stored; 5. The cold gas is directed upwardly through the second gas delivery port 121 into the cavity 14. The cold gas is then directed upwardly through the vents 61 on the second end 12 of the air distribution plate 6 into the heat storage tank 1. The alumina particles transfer heat to the cold air. After the cold air absorbs the heat, it is discharged from the heat storage tank 1 through the vents 61 on the air distribution plate 6 at the first end 11, the cavity 14, and the first gas delivery port 111. 6. The molten metal iron transfers heat to the cold air in the heat storage tank 1 through the heat storage tank 1, causing the liquid metal iron to release heat and solidify, so that the temperature of the phase change zone 3 is maintained at the phase change point temperature until all the liquid iron is solidified, completing the heat release process.

[0083] Comparative Example 1 application Figure 6 The energy storage system shown.

[0084] The energy storage system used in Comparative Example 1 includes only a heat storage tank and a thermal insulation layer, and does not include a phase change zone 3 and a thermal insulation zone 4. The energy storage method specifically includes: 1. Send nitrogen with a temperature of 1000°C downward into the heat storage tank. The nitrogen transfers heat to the alumina particles and then is discharged downward from the heat storage tank. 2. The insulation layer is used to prevent the heat inside the hot storage tank from being transferred to the outside and to perform thermal insulation until all the nitrogen is stored.

[0085] In summary, the energy storage system and method provided by this application, which couples sensible heat and phase change heat storage, improves the heat storage efficiency of the energy storage system itself, increases the heat storage temperature, and reduces the amount of insulation material used, thereby reducing heat storage costs. Furthermore, by changing the structure of the energy storage system itself, and combining phase change materials and porous materials to achieve efficient insulation, the requirements for insulation material performance are reduced, thereby broadening the types of insulation materials that can be used.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] The above is a detailed introduction to the energy storage system and method for coupling sensible heat and phase change heat storage 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 idea 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. An energy storage system that couples sensible heat and phase change heat storage, characterized in that: The energy storage system comprises: a heat storage tank (1) and a thermal insulation layer (2); The first end (11) of the heat storage tank (1) is provided with a first gas delivery port (111), and the second end (12) of the heat storage tank (1) opposite to the first end (11) is provided with a second gas delivery port (121), and the interior of the heat storage tank (1) is filled with a heat storage medium; A phase change zone (3) and a heat preservation zone (4) are provided between the heat storage tank (1) and the heat preservation layer (2) along a first direction, and the phase change zone (3) and the heat preservation zone (4), as well as the heat preservation zone (4) and the heat preservation layer (2) are separated by partitions (5); The phase change zone (3) is filled with a phase change material, and the heat preservation zone (4) is filled with a porous medium.

2. The energy storage system coupled with sensible heat and phase change heat storage according to claim 1, characterized in that: A plurality of storage tubes (13) are provided inside the heat storage tank (1), and the storage tubes (13) are used to store the phase change material; The storage pipes (13) are arranged in the heat storage tank (1) at intervals along a second direction perpendicular to the first direction, and the heat storage medium is located between two adjacent storage pipes (13).

3. The energy storage system coupled with sensible heat and phase change heat storage according to claim 2, characterized in that: The size of the material storage pipe (13) along the first direction is 0.5 m to 5 m.

4. The energy storage system coupled with sensible heat and phase change heat storage according to claim 1, characterized in that: The ratio of the total filling amount of the phase change material to the total filling amount of the heat storage medium is (1-1.5):

1.

5. The energy storage system coupled with sensible heat and phase change heat storage according to claim 1, characterized in that: The distance between the phase change material and the partition (5) between the phase change zone (3) and the heat preservation zone (4) is 0.5 m to 2 m.

6. The energy storage system coupled with sensible heat and phase change heat storage according to claim 1, characterized in that: A third gas delivery port (41) and a fourth gas delivery port (42) are respectively provided at opposite ends of the heat preservation zone (4), and the third gas delivery port (41) and the fourth gas delivery port (42) are used to deliver gas at room temperature.

7. The energy storage system coupled with sensible heat and phase change heat storage according to claim 1, characterized in that: The porous medium accounts for 30% to 50% of the total volume of the interior of the insulation zone (4).

8. The energy storage system coupled with sensible heat and phase change heat storage according to claim 1, characterized in that: The energy storage system further includes an air distribution plate (6); The air distribution plates (6) are respectively arranged at the first end (11) and the second end (12); The air distribution plate (6) is provided with a plurality of vent holes (61), and the vent holes (61) are connected to the first air delivery port (111) and the second air delivery port (121).

9. The energy storage system coupled with sensible heat and phase change heat storage according to claim 8, characterized in that: The total volume of the plurality of ventilation holes (61) accounts for 5% to 15% of the total volume of the air distribution plate (6).

10. A method for energy storage by coupling sensible heat and phase change heat storage, characterized in that: The method is applicable to the energy storage system coupled with sensible heat and phase change heat storage according to any one of claims 1 to 9, and the method comprises: A heat storage gas having a temperature of 500° C. to 1500° C. is fed into a heat storage tank (1) through a first gas delivery port (111); the heat storage gas transfers heat to a heat storage medium and then is discharged from the heat storage tank (1) through a second gas delivery port (121); The heat storage medium transfers heat to the phase change zone (3) through the heat storage tank (1), exchanges heat with the phase change material, and the phase change material melts due to the heat, and the temperature of the phase change zone (3) is maintained at the melting point temperature of the phase change material; The melted phase change material transfers part of the heat to the heat preservation zone (4) through the partition (5), and the porous medium absorbs the heat and maintains the temperature of the heat preservation zone (4) at 100°C to 250°C; The heat-insulating layer (2) is used to prevent the heat inside the heat-insulating zone (4) from being transferred to the outside, thereby maintaining heat; Wherein, the heat storage gas is any one of air, nitrogen and argon; The heat storage medium is any one of alumina particles, quartz sand particles, magnesium oxide particles, cast iron particles, high concrete particles and cement particles; The phase change material is any one of tin, aluminum and iron; The porous medium is aluminum oxide or magnesium oxide.

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