Energy storage system coupling sensible heat and phase change heat storage and method thereof

Abstract

The application provides an energy storage system coupling sensible heat and phase change heat storage and a method thereof. The energy storage system comprises a heat storage tank and an insulation layer. The first end of the heat storage tank is provided with a first gas inlet, and the second end opposite to the first end of the heat storage tank is provided with a second gas inlet. The heat storage tank is filled with a heat storage medium. The phase change region and the insulation region are arranged between the heat storage tank and the insulation layer along the first direction. The phase change region and the insulation region and the insulation layer are separated by a partition. The phase change region is filled with a phase change material, and the insulation region is filled with a porous medium. By adding the phase change region and the insulation region, the heat storage efficiency of the energy storage system itself is improved, and the heat storage temperature is increased, so that the amount of the insulation material is reduced, and the heat storage cost is reduced. Meanwhile, by changing the structure of the energy storage system, the phase change material and the porous material are combined to achieve the insulation effect, the performance requirement of the insulation material is reduced, and the applicable types of the insulation material are widened.

Description

Technical Field

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

[0002] Renewable energy is considered an effective means to replace traditional fossil fuels in the future. Renewable energy sources such as solar and wind power are considered to have enormous potential application value due to their abundant reserves, environmental friendliness, and ease of access. However, the inherent intermittency of these energy sources leads to a mismatch between energy supply and demand, thus necessitating the use of energy storage technologies to achieve effective dispatch of renewable energy.

[0003] Among various energy storage technologies, thermal energy storage has attracted widespread attention due to its high cost-effectiveness, energy conversion efficiency, and flexibly adjustable storage capacity. However, as the storage temperature of thermal storage tanks increases, the required thickness of insulation materials becomes enormous in order to reduce heat loss, leading to a significant increase in storage costs. Furthermore, the types of insulation materials that can be selected decrease accordingly with increasing storage temperatures, which is detrimental to achieving effective insulation. Summary of the Invention

[0004] To address the aforementioned issues, this application provides an energy storage system and method that couples sensible heat and phase change thermal storage. By adding a phase change zone and an insulation zone within the energy storage system, the system's thermal storage efficiency is improved, the thermal storage temperature is increased, and the amount of insulation material used is reduced, thereby lowering the thermal storage cost. Simultaneously, by modifying the energy storage system's structure, and in conjunction with phase change materials and porous materials, a more efficient insulation effect is achieved, reducing the performance requirements of the insulation materials and broadening the range of applicable insulation materials.

[0005] In a first aspect, this application provides an energy storage system that couples sensible heat and phase change heat storage, the energy storage system comprising: a thermal storage tank (1) and an insulation layer (2);

[0006] The first end (11) of the heat storage tank (1) is provided with a first gas outlet (111), and the second end (12) of the heat storage tank (1) opposite to the first end (11) is provided with a second gas outlet (121). The heat storage tank (1) is filled with a heat storage medium.

[0007] 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 the first direction. The phase change zone (3) and the heat preservation zone (4) are separated from each other by a partition (5).

[0008] The phase change zone (3) is filled with a phase change material, and the insulation zone (4) is filled with a porous medium.

[0009] Furthermore, the thermal storage tank (1) is provided with a plurality of storage pipes (13), which are used to store the phase change material;

[0010] The storage pipes (13) are spaced apart in the heat storage tank (1) along a second direction perpendicular to the first direction, and the heat storage medium is located between two adjacent storage pipes (13).

[0011] Furthermore, the storage pipe (13) has a dimension of 0.5 m to 5 m along the first direction.

[0012] 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.

[0013] Furthermore, the distance between the phase change material and the partition (5) between the phase change region (3) and the insulation region (4) is 0.5 m to 2 m.

[0014] Furthermore, a third gas inlet (41) and a fourth gas inlet (42) are respectively provided at opposite ends of the heat preservation zone (4), and the third gas inlet (41) and the fourth gas inlet (42) are used to transport room temperature gas.

[0015] Furthermore, the porous medium occupies 30% to 50% of the total volume inside the insulation zone (4).

[0016] Furthermore, the energy storage system also includes a wind distribution plate (6);

[0017] The air distribution plate (6) is respectively disposed at the first end (11) and the second end (12);

[0018] The air distribution plate (6) has multiple ventilation holes (61) which are connected to the first air inlet (111) and the second air inlet (121).

[0019] 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).

[0020] Secondly, this application provides an energy storage method that couples sensible heat and phase change thermal storage, the method being applicable to the energy storage system that couples sensible heat and phase change thermal storage as described in the first aspect, the method comprising:

[0021] A heat storage gas with a temperature of 500 ℃~1500 ℃ is sent into the heat storage tank (1) through the first gas inlet (111). After the heat storage gas transfers heat to the heat storage medium, it is discharged from the heat storage tank (1) through the second gas inlet (121).

[0022] The heat storage medium transfers heat to the phase change zone (3) through the heat storage tank (1) and exchanges heat with the phase change material. The phase change material melts when heated, and the temperature of the phase change zone (3) is maintained at the melting point temperature of the phase change material.

[0023] The molten phase change material transfers some of its heat to the insulation zone (4) through the partition (5), and the porous medium absorbs heat and maintains the temperature of the insulation zone (4) at 100 ℃~250 ℃;

[0024] The insulation layer (2) is used to prevent the heat inside the insulation area (4) from being transferred to the outside, thus providing insulation.

[0025] The heat storage gas is any one of air, nitrogen, and argon;

[0026] The heat storage medium is any one of alumina particles, quartz sand particles, and cement particles.

[0027] The phase change material is any one of tin, aluminum, and iron;

[0028] The porous medium is aluminum oxide or magnesium oxide.

[0029] In summary, this application includes at least one of the following beneficial technical effects:

[0030] 1. This application provides an energy storage system that couples sensible heat and phase change thermal storage. By filling a thermal storage tank with a thermal storage medium and setting a phase change zone, and filling the phase change zone with a phase change material, efficient energy storage is achieved through coupling sensible heat and phase change thermal storage. The phase change material can absorb or release a large amount of heat during the phase change process, while the thermal storage medium further increases the energy storage capacity through sensible heat storage. This allows the device to efficiently store heat within different temperature ranges, improving energy storage efficiency and flexibility. Furthermore, by setting an insulation zone and filling it with a porous medium, heat loss can be further reduced, especially at higher storage temperatures, effectively retaining heat and reducing heat loss from the thermal storage tank. The structure of the phase change zone and insulation zone enables the energy storage system itself to achieve high insulation performance, thereby reducing the amount and thickness of insulation material used, significantly reducing thermal storage costs. Moreover, by setting the phase change zone and insulation zone, the dependence on insulation material is reduced, allowing for the selection of more types of insulation materials and increasing the flexibility of insulation material selection.

[0031] 2. This application provides an energy storage method that couples sensible heat and phase change thermal energy storage. This method, by coupling sensible heat and phase change thermal energy storage, enables the thermal storage gas to transfer heat to the thermal storage medium at a high temperature of 500 ℃~1500 ℃, achieving efficient thermal energy storage. Then, the heat is further transferred to the phase change material. After the phase change material is heated and melted, it can maintain its melting point temperature for a long time, keeping the temperature of the phase change zone constant. At the same time, it absorbs a large amount of heat, further improving the energy storage density and efficiency, and helping to reduce heat loss. The molten 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, storing the heat and maintaining the temperature of the insulation zone between 20 ℃~30 ℃, further reducing the heat loss. This 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 thermal storage cost. Since the insulation material blocks the temperature loss at a low level, the selection range of insulation materials is wider. Attached Figure Description

[0032] 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.

[0033] Figure 1 A schematic diagram of the structure of the energy storage system that couples sensible heat and phase change thermal energy storage according to an embodiment of this application is shown;

[0034] Figure 2 This paper shows a cross-sectional structural schematic diagram of the thermal storage tank and phase change zone proposed in an embodiment of this application;

[0035] Figure 3 A schematic diagram of the air distribution plate proposed in an embodiment of this application is shown;

[0036] Figure 4 A flowchart of the energy storage method combining sensible heat and phase change thermal energy storage proposed in an embodiment of this application is shown;

[0037] Figure 5 A flowchart of the heat release method for coupling sensible heat and phase change heat storage proposed in an embodiment of this application is shown;

[0038] Figure 6 The energy storage system used in Comparative Example 1 of this application is shown.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1. Thermal storage tank; 11. First end; 111. First gas inlet; 12. Second end; 121. Second gas inlet; 13. Storage pipe; 14. Cavity;

[0041] 2. Insulation layer;

[0042] 3. Phase transition region;

[0043] 4. Insulation zone; 41. Third air inlet; 42. Fourth air inlet;

[0044] 5. Partition;

[0045] 6. Air distribution panel; 61. Ventilation hole. Detailed Implementation

[0046] 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.

[0047] 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.

[0048] Among related technologies, renewable energy is considered an effective means to replace traditional fossil fuels in the future. Renewable energy sources such as solar and wind power are considered to have enormous potential application value due to their abundant resources, environmental friendliness, and ease of access. However, the inherent intermittency of these energy sources leads to a mismatch between energy supply and demand, thus requiring the use of energy storage technologies to achieve effective dispatch of renewable energy.

[0049] Among various energy storage technologies, thermal energy storage technology has attracted widespread attention due to its high cost-effectiveness, energy conversion efficiency, and flexibly adjustable 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. Sensible heat storage is the main form of thermal energy storage technology.

[0050] Sensible thermal energy storage: This method utilizes the temperature difference of substances to store thermal energy. In sensible thermal energy storage, heat is directly stored within the temperature of the substance, and when needed, the stored thermal energy is released through heat exchange. This energy storage method is relatively simple, but the storage density is low, and energy loss is likely to occur during the storage process.

[0051] In addition to the energy storage methods mentioned above, thermal insulation materials are usually required to wrap the outside of the thermal storage tank. However, the thermal storage temperature of current thermal storage tanks is getting higher and higher, and in order to reduce heat loss, the required thickness of the insulation material has become huge; on the other hand, as the thermal storage temperature increases, the types of insulation materials that can be selected are also reduced accordingly, which leads to higher costs for insulation materials.

[0052] To address the problems existing in related technologies, this application provides an energy storage system that couples sensible heat and phase change thermal storage, see [link to relevant documentation]. Figure 1 The system includes: a thermal storage tank 1 and an insulation layer 2;

[0053] The first end 11 of the heat storage tank 1 is provided with a first gas outlet 111, and the second end 12 of the heat storage tank 1, which is opposite to the first end 11, is provided with a second gas outlet 121. The heat storage tank 1 is filled with a heat storage medium.

[0054] A phase change zone 3 and a heat preservation zone 4 are provided between the thermal storage tank 1 and the heat preservation layer 2 along the first direction. 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 a partition 5.

[0055] The phase change zone 3 is filled with a phase change material, and the insulation zone 4 is filled with a porous medium.

[0056] It should be noted that the thermal storage tank 1 consists of a sealed tank body made of high-temperature and corrosion-resistant materials, such as stainless steel, carbon steel, etc.

[0057] The cross-sectional shape of the thermal storage tank 1 is rectangular, circular, etc.;

[0058] 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.

[0059] The first direction x is the direction extending along the width of the thermal storage tank 1;

[0060] The insulation layer 2 is a layered structure made of insulation material of a certain thickness. The insulation layer 2 is arranged along the first direction on the outside of the partition 5 set in the insulation area 4.

[0061] In this embodiment of the application, the thickness of the insulation layer 2 can be 0.5 m to 1 m. In specific implementation, the thickness of the insulation layer 2 can be set according to the size of the thermal storage tank 1.

[0062] Both the phase change zone 3 and the insulation zone 4 are sealed spaces. The two ends of two adjacent partitions 5 are connected. The two ends of the partition 5 between the phase change zone 3 and the insulation zone 4 are also connected to the outer wall of the heat storage tank 1, forming a sealed energy storage system.

[0063] The material of the partition 5 can be any of ceramic materials, refractory bricks, high-temperature alloys and heat-insulating fiber materials, and must not melt at 2000 ℃ and not react with phase change materials and heat-insulating materials.

[0064] The heat storage medium is any one of alumina particles, quartz sand particles, and cement particles;

[0065] The phase change material is a metallic element, which can be any one of tin, aluminum, and iron.

[0066] The porous medium is alumina or magnesium oxide.

[0067] In practice, the heat storage gas first enters the heat storage tank 1 downwards through the first gas inlet 111 and exchanges heat with the heat storage medium inside the tank, storing the heat in the medium. Then, the heat storage medium transfers heat to the phase change zone 3 through the outer wall of the heat storage tank 1, causing the phase change material to heat up and reach its melting point, beginning to melt. As the phase change material gradually melts, the temperature in the phase change zone 3 remains consistent with the melting point temperature of the phase change material, thus absorbing and storing the heat dissipated from the heat storage 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 for insulation, further reducing the heat diffused to the insulation layer 2. This significantly reduces the amount of heat that the insulation layer 2 needs to block for outward diffusion. In practice, this allows for a reduction in the thickness of the insulation layer 2, lowering heat storage costs. Furthermore, because the amount of heat diffused to the insulation layer 2 is smaller, a wider variety of insulation layer types can be selected, making it easier to achieve efficient insulation with a thinner insulation layer.

[0068] During heat release, cold gas is fed upward into the heat storage tank 1 through the second gas inlet 121 to exchange heat with the heat storage medium, and the cold gas absorbs heat and rises in temperature. After the temperature of the heat storage medium drops, it absorbs heat from the phase change material through the heat storage tank 1. After the temperature of the phase change material drops to the freezing point, it begins to condense. Heat release is completed after all the molten phase change material has condensed.

[0069] For specific implementation, please refer to Figure 1 The dimensions of the first end 11 and the second end 12 of the thermal storage tank 1 gradually decrease along the length of the thermal storage tank 1 in the first direction. 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 thermal storage tank 1 in the first direction. This reduces the surface area at both ends of the thermal storage tank 1. Since heat loss is proportional to surface area, the tapering design of the thermal storage tank 1 helps reduce heat loss, thereby improving the energy efficiency of the thermal storage tank 1. It also allows more thermal energy to be effectively stored and utilized, thus improving the thermal efficiency of the entire energy storage system.

[0070] As the dimensions at both ends of the thermal storage tank 1 gradually decrease, the thermal expansion in these areas also decreases accordingly. This helps alleviate the thermal stress generated inside the thermal storage tank 1 under high-temperature conditions, thereby improving the structural stability of the thermal storage tank 1. Furthermore, it reduces the deformation of the thermal storage tank 1 under temperature changes to a certain extent, further enhancing the overall structural reliability.

[0071] In some embodiments, see Figure 2 The thermal storage tank 1 is provided with a plurality of storage pipes 13, which are used to store the phase change material;

[0072] The storage pipes 13 are spaced apart in the heat storage tank 1 along a second direction perpendicular to the first direction, and the heat storage medium is located between two adjacent storage pipes 13.

[0073] It should be noted that the cross-sectional shape of the storage pipe 13 can be circular, rectangular, rhomboid, etc.

[0074] The number of storage pipes 13 is not specifically limited in this embodiment of the application. In specific implementation, they are arranged at intervals along the second direction in the heat storage tank 1 according to the size of the heat storage tank 1.

[0075] The connection between the storage pipe 13 and the hot storage tank 1 can be welding, threaded connection, riveting, etc., and is not specifically limited in this embodiment.

[0076] The material of the storage tube 13 can be stainless steel, corundum, or carbon fiber composite material, etc.

[0077] The distance between two adjacent storage pipes 13 shall not exceed 0.5 m. In specific implementation, the distance between the two storage pipes 13 shall be reasonably set according to the size of the hot storage tank 1.

[0078] The second direction y is the direction that extends along the length of the thermal storage tank 1.

[0079] In practice, during the heat storage process, phase change material is filled into storage pipe 13, heat storage medium is filled between two adjacent storage pipes 13, and between storage pipe 13 and the inner wall of heat storage tank 1. During the heat storage process, the heat storage medium and heat storage gas directly transfer heat to the phase change material through storage pipe 13, causing the phase change material to melt. The melted phase change material is stored in storage pipe 13 to avoid contaminating the heat storage medium.

[0080] By setting up the storage pipe 13, the heat storage gas can directly transfer heat to the phase change material through the storage pipe 13, thereby further reducing heat loss. During the melting process, the phase change material always maintains a constant melting point. The heat transferred by the heat storage gas is stored together by the phase change heat of the phase change metal and the heat storage medium, thereby greatly increasing the energy density of the heat storage tank 1 and improving the heat quality.

[0081] In some embodiments, the phase change material occupies 60% to 80% of the volume of the storage tube 13. This avoids filling the storage tube 13 with phase change material, providing sufficient space for the phase change material to melt and expand, and reducing safety hazards in the energy storage process.

[0082] In some embodiments, see Figure 2 The storage pipe 13 has a dimension of 0.5 m to 5 m along the first direction.

[0083] It should be noted that the dimension of the storage tube 13 along the first direction is the diameter of the storage tube 13 in the first direction.

[0084] In specific implementation, the dimensions 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.

[0085] By setting the size of the storage pipe 13, it is possible to arrange the internal space of the heat storage tank 1 more reasonably. This ensures that there is a sufficient amount of heat storage medium, while avoiding problems such as reduced heat transfer efficiency and insufficient structural strength caused by an excessively large storage pipe 13. This helps to optimize the overall size and weight of the heat storage tank 1, and reduce manufacturing costs and transportation difficulties.

[0086] In some embodiments, the ratio of the total amount of phase change material to the total amount of thermal storage medium is (1~1.5):1.

[0087] In practice, the ratio of the total filling amount of variable material to the total filling amount of heat storage medium can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1.

[0088] By setting the filling ratio of phase change material (PCM) to heat storage medium, the phase change energy storage characteristics of PCM and the sensible heat energy storage characteristics of heat storage medium are fully utilized inside the heat storage tank 1. The heat storage medium can absorb and store this heat, while PCM can absorb or release a large amount of heat during the phase change process, thereby improving the overall heat storage density and release efficiency of the heat storage tank 1.

[0089] Furthermore, the spaced arrangement of the storage pipes 13 along the second direction, combined with a reasonable filling ratio of phase change material and heat storage medium, helps to ensure the uniform distribution and transfer of heat energy inside the heat storage tank 1. During heat release, heat can be more effectively transferred from the phase change material in the storage pipes 13 to the heat storage medium, and then transferred to the cold gas through the heat storage medium. This improves the uniformity of heat energy transfer in the heat storage tank 1 and reduces heat loss during the transfer process.

[0090] In some embodiments, see Figure 1The distance between the phase change material and the partition 5 between the phase change zone 3 and the insulation zone 4 is 0.5 m to 2 m.

[0091] It should be noted that this distance is the vertical distance from the phase change material along the first direction to the side wall of the partition 5.

[0092] In practice, the distance between the phase change material and the partition 5 between the phase change zone 3 and the insulation zone 4 can be 0.5 m, 1 m, 1.5 m or 2 m.

[0093] Since the phase change material expands in volume when heated and melted, setting a certain distance ensures sufficient space between the phase change material and the partition 5. This prevents the phase change material from overflowing into the phase change zone 3 after melting and expanding, or from deforming the partition 5, thus helping to maintain the stability of the energy storage system structure.

[0094] In some embodiments, see Figure 1 The insulation zone 4 has a third gas inlet 41 and a fourth gas inlet 42 at opposite ends, which are used to transport room temperature gas.

[0095] It should be noted that, in one case, the third air inlet 41 is located at the upper end of the insulation zone 4 and the fourth air inlet 42 is located at the lower end of the insulation zone 4; in another case, the third air inlet 41 is located at the left end of the insulation zone 4 and the fourth air inlet 42 is located at the right end of the insulation zone 4; the third air inlet 41 and the first air inlet 111 are arranged parallel to each other on the same axis, and the fourth air inlet 42 and the second air inlet 121 are arranged parallel to each other on the same axis.

[0096] Gases at room temperature can be air, nitrogen, argon, etc.

[0097] The temperature of the gas at room temperature is set to 20 ℃~30 ℃.

[0098] By opening a third gas inlet 41 and a fourth gas inlet 42 in the insulation zone 4, ambient temperature gas is fed into the insulation zone 4 through the third gas inlet 41. After flowing downwards, the ambient temperature gas comes into contact with the porous medium and exchanges heat, making it easier to maintain the temperature of the porous medium between 20 ℃ and 30 ℃. This, in turn, keeps the temperature of the insulation zone 4 between 20 ℃ and 30 ℃, preventing the porous medium from absorbing too much heat and causing the temperature of the insulation zone 4 to rise. The gas after heat exchange is discharged downwards through the fourth gas inlet 42 from the insulation zone 4, and then new ambient temperature gas is discharged into the insulation zone 4 through the third gas inlet 41, forming a cycle to ensure that the temperature of the insulation zone 4 remains within the specified range.

[0099] In some embodiments, see Figure 1 The porous medium accounts for 30% to 50% of the total internal volume of the insulation zone 4.

[0100] In specific implementation, the porous medium occupies 30%, 35%, 45% or 50% of the total internal volume of the insulation zone 4.

[0101] By adjusting the volume of the porous medium, the temperature of the insulation zone 4 can be kept constant, while the amount of porous medium used can be reduced, thus saving energy storage costs.

[0102] In some embodiments, see Figure 2 The system also includes an air distribution plate 6;

[0103] The air distribution plate 6 is respectively disposed at the first end 11 and the second end 12;

[0104] The air distribution plate 6 has multiple ventilation holes 61, which are connected to the first air inlet 111 and the second air inlet 121.

[0105] It should be noted that the cross-sectional shape of the air distribution plate 6 can be rectangular, circular, elliptical, etc.

[0106] The shape of the air distribution plate 6 is adapted to the heat storage tank 1;

[0107] The dimension of the air distribution plate 6 along the first direction is larger than the dimension of the first air inlet 111 and the second air inlet 121 along the first direction;

[0108] The material of the air distribution plate 6 is not specifically limited in this embodiment. However, the material of the air distribution plate 6 needs to meet the following requirements: its melting point must be below 2000 °C to ensure that it does not melt during the heat storage and release process; and the air distribution plate 6 must have stable physical and chemical properties and not react chemically with the heat storage gas and heat storage medium.

[0109] In practical implementation, by setting up the air distribution plate 6 and placing it at the first end 11 and the second end 12 of the heat storage tank 1, the multiple vents 61 on it can evenly distribute and guide the flow of the heat storage gas, making the flow of the heat storage gas within the heat storage tank 1 more uniform. The multiple vents 61 are connected to the first air inlet 111 and the second air inlet 121, ensuring that the heat storage gas can smoothly enter and exit the heat storage tank 1, which helps to increase the contact area and contact time between the heat storage gas and the heat storage medium, thereby improving heat exchange efficiency. Furthermore, by evenly distributing the vents 61 on the air distribution plate 6, it helps to reduce local overheating or cooling phenomena within 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 act 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.

[0110] For specific implementation, please refer to Figure 2The air distribution plate 6 is installed on the inner wall of the heat storage tank 1 near the first air outlet 111 and the second air outlet 121. The two ends of the storage pipe 13 are respectively connected to the two air distribution plates 6 one by one and fixedly connected. The heat storage medium is filled between the two air distribution plates 6 to restrict the movement of the heat storage medium and ensure the stability of heat transfer.

[0111] For specific implementation, please refer to Figure 2 A cavity 14 is formed between the air distribution plate 6 and the first air inlet 111 and the second air inlet 121. The presence of the cavity 14 forms an additional heat insulation layer, reducing the direct transfer of heat to the external environment through the wall of the heat storage tank 1, which helps to further reduce heat loss and improve the heat insulation performance of the heat storage tank 1. Especially under high temperature conditions, the heat insulation effect of the cavity 14 is particularly significant, which helps to maintain the high temperature state of the heat storage medium and extend the storage time of thermal energy.

[0112] The presence of cavity 14 also alters the heat transfer path within the heat storage tank 1. During heat transfer, the heat must first pass through the heat storage medium, then be insulated by the cavity 14, and finally dissipate to the external environment through the walls of the heat storage tank 1. This extended path helps slow down the rate of heat loss, allowing heat to remain in the heat storage medium for a longer period, thereby improving the thermal energy utilization efficiency of the heat storage tank 1.

[0113] 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.

[0114] It should be noted that the total volume of the multiple vents 61 accounts for 5% to 15% of the total volume of the air distribution plate 6, indicating that the porosity of the air distribution plate 6 is 5% to 15%.

[0115] In practical implementation, by setting a specific proportion of the total volume of multiple vents 61 to the total volume of the air distribution plate 6, the heat storage gas can be evenly distributed on the air distribution plate 6. The number of vents 61 helps balance the gas flow velocity and pressure, avoiding 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 / cold gas to promote effective heat exchange.

[0116] Secondly, see Figure 4 This application provides an energy storage method that couples sensible heat and phase change thermal storage, the method comprising:

[0117] Step S1: The heat storage gas with a temperature of 500 ℃~1500 ℃ is sent into the heat storage tank 1 through the first gas inlet 111. After the heat storage gas transfers heat to the heat storage medium, it is discharged from the heat storage tank 1 through the second gas inlet 121.

[0118] Step S2: The heat storage medium transfers heat to the phase change zone 3 through the heat storage tank 1, and exchanges heat with the phase change material. The phase change material melts when heated, and the temperature of the phase change zone 3 is maintained at the melting point temperature of the phase change material.

[0119] Step S3: The molten phase change material transfers some of its heat to the insulation zone 4 through the partition 5. The porous medium absorbs heat and maintains the temperature of the insulation zone 4 at 20 ℃~30 ℃.

[0120] Step S4: The insulation layer 2 is used to prevent the heat inside the insulation zone 4 from being transferred to the outside, thus providing insulation.

[0121] The heat storage gas is any one of air, nitrogen, and argon;

[0122] The heat storage medium is any one of alumina particles, quartz sand particles, and cement particles.

[0123] The phase change material is any one of tin, aluminum, and iron;

[0124] The porous medium is aluminum oxide or magnesium oxide.

[0125] It should be noted that in the energy storage system, the 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 mainly transferred to the heat storage medium through convection and radiation.

[0126] Convection refers to the heat transfer caused by temperature differences when the heat storage gas flows in the heat storage tank 1; while radiation is the transfer of heat from a high-temperature object (heat storage gas) to a low-temperature object (heat storage medium) in the form of electromagnetic waves.

[0127] Factors affecting 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. These properties directly affect the efficiency and effect of heat transfer.

[0128] Based on the above, the flow rate of the heat storage gas in this embodiment can be set to 0.2-15 m / s. This achieves high heat exchange efficiency and retains heat within the heat storage tank 1 as much as possible.

[0129] The heat storage medium selected in this application embodiment is a granular material with a particle size of <10 cm, which can greatly increase the heat exchange area; the melting point of the granular material is less than 2000 ℃, which can be used as a high-temperature heat storage material, with good physical and chemical stability, and does not react with the heat storage gas.

[0130] The phase change material selected in this application embodiment is a metallic element with a melting point between 230 ℃ and 1500 ℃;

[0131] When the temperature of the heat storage gas delivered by the first gas inlet 111 is 500 ℃~800 ℃, metallic tin or metallic aluminum is used as a phase change material to fill the phase change zone 3; when the temperature of the heat storage gas delivered by the first gas inlet 111 is 1000 ℃~1500 ℃, metallic iron is used as a phase change material to fill the phase change zone 3.

[0132] In this embodiment, the insulation layer 2 is composed of conventional insulation materials. These materials have low thermal conductivity, enabling effective insulation in various environments; their melting point is below 1000°C, thus greatly expanding the selection of insulation materials.

[0133] In this embodiment, the heat storage gas selected 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 ℃ to 1500 ℃. In specific implementation, the heat storage inlet temperature can be adjusted according to the requirements.

[0134] The porous media selected in this application embodiment—alumina or magnesium oxide—not only possess excellent thermal conductivity, enabling rapid absorption of heat from the phase change material, but also exhibit high specific heat capacity. The porous structure of the media increases its surface area, which is beneficial for heat transfer and storage.

[0135] Higher porosity results in a larger surface area for the porous medium, which is more conducive to heat transfer and storage. The alumina and magnesium oxide selected in this embodiment have a porosity of approximately 0.4.

[0136] The insulation layer 2 selected in this embodiment needs to be resistant to high temperature and have a low thermal conductivity. It can be made of ceramic fiber, aerogel or multilayer composite material, etc., which can effectively block the transfer of heat and reduce heat loss.

[0137] The energy storage method combining sensible heat and phase change thermal energy storage provided in this application, compared to traditional single energy storage methods, can fully utilize the temperature difference of the thermal storage medium and the latent heat of phase change of the phase change material, thereby significantly increasing the energy storage density. Simultaneously, since the phase change energy storage process takes place at a relatively constant temperature, i.e., the melting point temperature of the phase change material, energy loss is relatively small, thus improving energy storage efficiency.

[0138] Furthermore, by introducing a porous medium, heat loss within the thermal 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℃~30℃), 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 stability and efficiency of the energy storage system. By setting up the phase change zone 3 and the insulation zone 4, even at higher thermal storage temperatures, the thickness and type limitations of the insulation material can be effectively reduced, lowering the cost of the insulation layer 2 and improving the economics and feasibility of the energy storage system.

[0139] For specific implementation, please refer to Figure 5 The flowchart illustrates the heat release method for coupling sensible heat and phase change heat storage proposed in this application embodiment. The specific processing steps include:

[0140] Step S11: Cold gas is conveyed upward through the second gas inlet 121 into the heat storage tank 1. The heat storage medium transfers heat to the cold air. After the cold air absorbs heat, it is discharged from the heat storage tank 1 through the first gas inlet 111.

[0141] Step S12: The phase change material transfers heat to the cold air inside the heat storage tank 1 through the heat storage tank 1. 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 material is solidified, thus completing the heat release process.

[0142] Because the energy storage system provided in this application embodiment can store higher temperatures, it also releases more heat when releasing heat, making the cold gas temperature higher and achieving efficient energy storage.

[0143] To enable those skilled in the art to more clearly understand this application, the following embodiments will be used to provide a detailed description of an energy storage system and method that couples sensible heat and phase change thermal energy storage as described in this application.

[0144] Example 1

[0145] application Figure 1 The energy storage system shown is a combination of sensible heat and phase change thermal energy storage.

[0146] 1. Nitrogen gas at a temperature of 1000 ℃ is delivered into the cavity 14 through the first gas inlet 111, and then enters the heat storage tank 1 through the vent 61 on the air distribution plate 6 at the first end 11. After the nitrogen gas transfers heat to the alumina particles, it reaches the air distribution plate 6 at the second end 12 and is discharged from the heat storage tank 1 through the vent 61 on the air distribution plate 6 at the second end 12, the cavity 14, and the second gas inlet 121 in sequence.

[0147] 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 heated and melted, and the temperature of the phase change zone 3 is maintained at the melting point temperature of the metallic iron.

[0148] 3. After the molten iron is melted, some of the heat is transferred to the heat preservation zone 4 through the partition 5. The porous magnesium oxide in the heat preservation zone 4 absorbs heat. At the same time, room temperature air is transported down to the heat preservation zone 4 through the third air inlet 41 and then discharged down to the heat preservation zone 4 through the fourth air inlet 42, together maintaining the temperature of the heat preservation zone 4 at 25 ℃.

[0149] 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 nitrogen has been stored.

[0150] Example 2

[0151] The main difference between Example 2 and Example 1 lies in the temperature of the heat storage gas and the phase change material.

[0152] 1. Air at a temperature of 650 ℃ is delivered into the cavity 14 through the first air inlet 111, and then enters the heat storage tank 1 through the vent 61 on the air distribution plate 6 at the first end 11. The air transfers heat to the quartz sand particles and then reaches the air distribution plate 6 at the second end 12. It is then discharged from the heat storage tank 1 through the vent 61 on the air distribution plate 6 at the second end 12, the cavity 14, and the second air inlet 121 in sequence.

[0153] 2. The quartz sand particles transfer the absorbed heat to the phase change zone 3 through the heat storage tank 1. The metallic tin in the phase change zone 3 is heated and melted, and the temperature of the phase change zone 3 is maintained at the melting point temperature of metallic tin.

[0154] 3. The molten tin transfers some of its heat to the insulation zone 4 through the partition 5. The porous alumina in the insulation zone 4 absorbs the heat. At the same time, room temperature air is transported downwards to the insulation zone 4 through the third air inlet 41 and then discharged downwards from the insulation zone 4 through the fourth air inlet 42, together maintaining the temperature of the insulation zone 4 at 25 ℃.

[0155] 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 air has completed energy storage.

[0156] Example 3

[0157] The difference between Example 3 and Example 1 is that the heat storage tank 1 used in Example 3 is equipped with a storage pipe 13.

[0158] 1. Nitrogen gas at a temperature of 1000 ℃ is delivered into the cavity 14 through the first gas inlet 111, and then enters the hot storage tank 1 through the vent 61 on the air distribution plate 6 at the first end 11. The nitrogen gas transfers heat to the alumina particles and the metallic iron in the storage pipe 13, and then reaches the air distribution plate 6 at the second end 12. It is discharged from the hot storage tank 1 through the vent 61 on the air distribution plate 6 at the second end 12, the cavity 14, and the second gas inlet 121 in sequence. The metallic iron is heated and melts, and the temperature in the storage pipe 13 is maintained at the melting point temperature of the metallic iron.

[0159] 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 heated and melted, and the temperature of the phase change zone 3 is maintained at the melting point temperature of the metallic iron.

[0160] 3. After the molten iron is melted, some of the heat is transferred to the heat preservation zone 4 through the partition 5. The porous magnesium oxide in the heat preservation zone 4 absorbs heat. At the same time, room temperature air is transported down to the heat preservation zone 4 through the third air inlet 41 and then discharged down to the heat preservation zone 4 through the fourth air inlet 42, together maintaining the temperature of the heat preservation zone 4 at 25 ℃.

[0161] 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 nitrogen has been stored.

[0162] Example 4

[0163] The difference between Example 4 and Example 1 is that Example 3 further includes an exothermic step, specifically:

[0164] 1. Nitrogen gas at a temperature of 1000 ℃ is delivered into the cavity 14 through the first gas inlet 111, and then enters the heat storage tank 1 through the vent 61 on the air distribution plate 6 at the first end 11. After the nitrogen gas transfers heat to the alumina particles, it reaches the air distribution plate 6 at the second end 12 and is discharged from the heat storage tank 1 through the vent 61 on the air distribution plate 6 at the second end 12, the cavity 14, and the second gas inlet 121 in sequence.

[0165] 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 heated and melted, and the temperature of the phase change zone 3 is maintained at the melting point temperature of the metallic iron.

[0166] 3. After the molten iron is melted, some of the heat is transferred to the heat preservation zone 4 through the partition 5. The porous magnesium oxide in the heat preservation zone 4 absorbs heat. At the same time, room temperature air is transported down to the heat preservation zone 4 through the third air inlet 41 and then discharged down to the heat preservation zone 4 through the fourth air inlet 42, together maintaining the temperature of the heat preservation zone 4 at 25 ℃.

[0167] 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 nitrogen has been stored.

[0168] 5. Cold gas enters the cavity 14 upward through the second air inlet 121. The cold gas is then transported upward through the vent 61 on the second end 12 of the air distribution plate 6 to the heat storage tank 1. The alumina particles transfer heat to the cold air. After absorbing the heat, the cold air is discharged from the heat storage tank 1 through the vent 61 on the air distribution plate 6 at the first end 11, the cavity 14, and the first air inlet 111.

[0169] 6. The molten iron transfers heat to the cold air inside the heat storage tank 1, causing the liquid iron to release heat and solidify, thus maintaining the temperature of the phase change zone 3 at the phase change point temperature until all the liquid iron is solidified, completing the heat release process.

[0170] Comparative Example 1

[0171] application Figure 6 The energy storage system shown.

[0172] The energy storage system used in Comparative Example 1 only includes a thermal storage tank and an insulation layer, without phase change zone 3 and insulation zone 4. The specific energy storage methods include:

[0173] 1. Nitrogen gas at a temperature of 1000 ℃ is fed downward into the heat storage tank. The nitrogen gas transfers heat to the alumina particles and then is discharged downward from the heat storage tank.

[0174] 2. The insulation layer is used to prevent heat from the inside of the thermal storage tank from being transferred to the outside, and to keep it warm until all the nitrogen has been stored.

[0175] In summary, this application provides an energy storage system and method that couples sensible heat and phase change thermal storage. By adding a phase change zone and an insulation zone within the energy storage system, the thermal storage efficiency of the system itself is improved, the thermal storage temperature is increased, and the amount of insulation material used is reduced, thereby lowering the thermal storage cost. Simultaneously, through changes in the energy storage system's structure, combined with phase change materials and porous materials, a highly efficient insulation effect is achieved, reducing the performance requirements of the insulation materials and thus broadening the range of applicable insulation materials.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] The above provides a detailed description of an energy storage system and method that couples sensible heat and phase change thermal energy storage, as provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are 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. An energy storage system coupling sensible heat and phase change thermal storage, characterized in that, The energy storage system includes: a thermal storage tank (1) and an insulation layer (2); The first end (11) of the heat storage tank (1) is provided with a first gas outlet (111), and the second end (12) of the heat storage tank (1) opposite to the first end (11) is provided with a second gas outlet (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 the first direction. The phase change zone (3) and the heat preservation zone (4) are separated from each other by a partition (5). The phase change zone (3) is filled with a first phase change material, and the heat preservation zone (4) is filled with a porous medium, which is alumina or magnesium oxide. The insulation zone (4) has a third gas inlet (41) and a fourth gas inlet (42) at opposite ends. The third gas inlet (41) and the fourth gas inlet (42) are used to transport room temperature gas that exchanges heat with the porous medium, so that the temperature of the insulation zone (4) is kept within a limited range.

2. The energy storage system coupling sensible heat and phase change thermal storage according to claim 1, characterized in that, The heat storage tank (1) is provided with a plurality of storage pipes (13), which are used to store the second phase change material; The storage pipes (13) are spaced apart in the heat storage tank (1) 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 coupling sensible heat and phase change thermal storage according to claim 2, characterized in that, The storage pipe (13) has a dimension of 0.5 m to 5 m along the first direction.

4. The energy storage system coupling sensible heat and phase change thermal storage according to claim 2, characterized in that, The ratio of the total filling amount of the second phase change material to the total filling amount of the heat storage medium is (1~1.5):

1.

5. The energy storage system coupling sensible heat and phase change thermal storage according to claim 2, characterized in that, The distance between the second 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 coupling sensible heat and phase change thermal storage according to claim 1, characterized in that, The porous medium accounts for 30% to 50% of the total volume inside the insulation zone (4).

7. The energy storage system coupling sensible heat and phase change thermal storage according to claim 1, characterized in that, The energy storage system also includes a wind distribution plate (6); The air distribution plate (6) is respectively disposed at the first end (11) and the second end (12); The air distribution plate (6) has multiple ventilation holes (61) which are connected to the first air inlet (111) and the second air inlet (121).

8. The energy storage system coupling sensible heat and phase change thermal storage according to claim 7, 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).

9. An energy storage method coupling sensible heat and phase change thermal storage, characterized in that, The method is applicable to the energy storage system coupled with sensible heat and phase change thermal storage as described in any one of claims 1 to 8, and the method includes: A heat storage gas with a temperature of 500 ℃~1500 ℃ is sent into the heat storage tank (1) through the first gas inlet (111). After the heat storage gas transfers heat to the heat storage medium, it is discharged from the heat storage tank (1) through the second gas inlet (121). The heat storage medium transfers heat to the phase change zone (3) through the heat storage tank (1) and exchanges heat with the first phase change material. The first phase change material melts when heated, and the temperature of the phase change zone (3) is maintained at the melting point temperature of the first phase change material. After melting, the first phase change material transfers some of its heat to the insulation zone (4) through the partition (5). The porous medium absorbs heat and maintains the temperature of the insulation zone (4) at 100 ℃~250 ℃. The insulation layer (2) is used to prevent the heat inside the insulation area (4) from being transferred to the outside, thus providing insulation. 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-strength concrete particles, and cement particles. The first phase change material is any one of tin, aluminum, and iron; The porous medium is aluminum oxide or magnesium oxide.

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