Heat storage body, heat storage system and heat storage and release process

Abstract

This invention discloses a thermal storage body, a thermal storage system, and a thermal storage and release process, relating to the field of thermal storage technology. The thermal storage body comprises a matrix powder and a thermally conductive modified powder. The matrix powder includes sand, and the thermally conductive modified powder includes graphite powder. The thermal conductivity of the sand is 0.15–0.25 W / (m·K), and the thermal conductivity of the graphite powder is 70–150 W / (m·K). The thermal storage system comprises a thermal storage body, a closed thermal storage unit, and heat exchange tubes. The closed thermal storage unit houses the thermal storage body. The heat exchange tubes pass through the closed thermal storage unit and the thermal storage body, with their first and second ends located outside the closed thermal storage unit. The thermal storage and release process utilizes the thermal storage system and includes opening a thermal storage circulation loop, closing the thermal storage circulation loop, and opening a heat release circulation loop. Compared to existing technologies, this invention addresses the needs of low cost, high thermal conductivity, modularity, versatility, and long-term thermal storage across various scenarios, solving the problem of insufficient overall performance of existing sandy thermal storage materials and equipment.

Description

Technical Field

[0001] This invention relates to the field of thermal storage technology, and in particular to a thermal storage body, a thermal storage system, and a thermal storage and release process. Background Technology

[0002] Guided by the global dual-carbon development goals, the installed capacity of wind power and photovoltaic new energy in China continues to climb. However, the output of wind and solar power fluctuates significantly with weather conditions. There is a serious mismatch between the supply of heat and electricity and the energy demand of users, resulting in a large amount of renewable energy not being fully utilized. The industry urgently needs low-cost thermal storage solutions that can cover short-term peak shaving, medium-term energy storage, and long-term thermal storage across seasons.

[0003] Currently, mainstream energy storage technologies each have significant application shortcomings: electrochemical energy storage has high initial investment costs and short cycle life, making it unsuitable for large-scale centralized energy storage projects; pumped hydro storage and compressed air storage have stringent requirements for site topography, require huge upfront civil engineering investments, and have very limited applicable areas; conventional water thermal storage operates at low temperatures and can only produce low-grade heat, limiting its applicability to a single scenario; molten salt thermal storage has good heat exchange performance, but the raw materials are expensive, resulting in poor overall project economics and making it difficult to widely adopt.

[0004] Sand and gravel raw materials have abundant reserves and low purchase prices, and have the advantages of high temperature resistance and large heat storage capacity, making them an ideal basic medium in the field of solid sensible heat storage. However, pure sand and gravel have weak thermal conductivity and slow heat charging and releasing rates when used alone. To ensure heat exchange efficiency, heat exchange pipes must be densely arranged, which not only increases the fluid resistance of the pipes but also increases the manufacturing cost of the entire device.

[0005] Existing sandy thermal energy storage improvement schemes generally suffer from an imbalance in overall performance. Some improvement schemes require additional protective devices, resulting in complex equipment structures, high operation and maintenance costs, insufficient continuity of internal heat conduction networks, and uneven temperature distribution within the storage body. Furthermore, some improvement schemes use expensive thermally conductive modification materials, significantly increasing material input for large-scale thermal energy storage operations. Related equipment is mostly designed for single operating conditions, lacking modular and universal structures that can be freely assembled and flexibly adjusted to accommodate varying energy storage scales. There is also a lack of design concepts for multi-component powder synergistic modification, making it impossible to flexibly adjust the composition of thermal energy storage materials according to different operating temperatures and cost budgets. Consequently, it is difficult to simultaneously achieve multiple indicators such as low cost, high thermal conductivity, stable operation over a wide temperature range, and long-term cross-seasonal thermal energy storage, making it unsuitable for various engineering scenarios such as renewable energy power generation and consumption, industrial waste heat recovery, urban centralized heating, and integrated energy supply for industrial parks. Summary of the Invention

[0006] The purpose of this invention is to provide a thermal storage body, thermal storage system, and thermal storage and release process that takes into account the requirements of low cost, high thermal conductivity, modularity and versatility, and long-term thermal storage in all scenarios, and solves the problem of insufficient comprehensive performance of existing sandy thermal storage materials and equipment.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention discloses a heat storage body, comprising a matrix powder and a thermally conductive modified powder. The matrix powder comprises sand, and the thermally conductive modified powder comprises graphite powder. The thermal conductivity of the sand is 0.15–0.25 W / (m·K), and the thermal conductivity of the graphite powder is 70–150 W / (m·K).

[0008] In some examples, the mass ratio of the sand to the graphite powder is 90–97:3–10.

[0009] The present invention also discloses a thermal storage system, including the above-described thermal storage body, and further comprising: A closed thermal storage unit is used to house the thermal storage body. A heat exchange tube passes through the closed heat storage unit and the heat storage body, with its first end and second end located outside the closed heat storage unit; one of the first end and the second end is used for the flow of heat exchange medium, and the other is used for the flow of heat exchange medium out.

[0010] In some examples, the enclosed thermal storage unit is an above-ground metal container or an underground reinforced concrete pit.

[0011] In some examples, the heat exchange tubes are coils, spirals, or serpentine tubes.

[0012] In some examples, the heat exchange medium is heat transfer oil, molten salt, or antifreeze.

[0013] In some examples, both the first and second ends are equipped with temperature sensors, pressure sensors, and flow sensors.

[0014] In some examples, the thermal storage system further includes a heat source connected to the first end and the second end respectively, to establish a thermal storage circulation loop.

[0015] In some examples, the thermal storage system further includes a heat exchanger connected to the first end and the second end respectively to establish a heat release circulation loop.

[0016] This invention also discloses a heat storage and release process using the above-mentioned heat storage system, comprising the following steps: S1 heat storage stage, the heat storage circulation loop is opened, the heat exchange medium absorbs heat through the heat source and flows through the heat exchange tube to store heat in the heat storage body; S2 heat preservation stage, the heat storage circulation loop is cut off, and static heat storage is achieved by relying on the closed heat storage unit for airtight heat preservation; S3 heat release stage, the heat release circulation loop is opened, the heat exchange medium carries away the heat of the heat storage body and delivers it to the heat exchanger for external heat supply.

[0017] Compared with related technologies, the present invention achieves the following technical effects: This invention uses sand as the main matrix powder and graphite powder as the thermally conductive modified powder to make a thermal storage body. Sand is readily available and has low procurement costs, and can provide sufficient thermal storage capacity. Graphite powder can build continuous thermally conductive channels inside the powder, which greatly improves the overall thermal conductivity of the thermal storage body and solves the defects of traditional single sand thermal storage materials such as slow heat transfer, large internal temperature difference and low heat charging and discharging efficiency. The ratio of the two materials is limited to 90-97:3-10, taking into account heat storage density, thermal conductivity and material cost. The optimal ratio of 95:5 can maximize the overall performance. At the same time, the material can be extended to various powder composite modifications to adapt to different working conditions.

[0018] The thermal storage system is equipped with a closed thermal storage unit, which can be either an above-ground metal container or an underground reinforced concrete pit. The modular structure can be flexibly arranged according to the energy storage scale. The pit structure can also be insulated with soil to reduce heat loss. The system is equipped with heat exchange tubes as indirect heat exchange components. The heat exchange medium is completely separated from the thermal storage body to avoid powder blockage and pipeline wear, thus extending the service life of the equipment.

[0019] Both the first and second ends of the heat exchange tube are equipped with temperature, pressure, and flow sensors, which can monitor the operating parameters of the medium in real time, identify faults such as leakage, blockage, and overpressure in a timely manner, and realize intelligent control of the entire process of heat storage and release.

[0020] The system is equipped with a heat source to construct an independent heat storage circulation loop and a heat release circulation loop to construct a heat exchanger. The two loops do not interfere with each other and can be started and stopped independently. The heat exchange medium is circulated by a circulation pump, which efficiently recovers low-grade heat energy such as solar energy and industrial waste heat, and realizes peak-shifting heat energy storage and on-demand external heating.

[0021] The entire heat storage and release process is divided into three stages: heat storage, heat preservation, and heat release. It relies on closed heat storage units and supporting high-efficiency heat preservation structures to achieve long-term static heat storage. It can cover all scenarios of short-term, medium-term, long-term and cross-seasonal energy storage and is suitable for various fields such as photovoltaic and wind power consumption, industrial waste heat recovery, and urban centralized heating. The entire system is modular and easy to install and disassemble. Its performance degradation is extremely low over long-term and multiple cycles of charging and discharging. Compared with existing energy storage solutions such as electrochemical, molten salt, and pumped storage, the engineering investment and operating costs are significantly reduced. It is not limited by geographical conditions and has higher value for large-scale promotion. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the combination of a closed thermal storage unit and a heat exchange tube in some examples of the present invention; Figure 2 This is a schematic diagram of a heat exchanger tube arrangement in a serpentine configuration. Figure 3 This is a schematic diagram when the heat exchange tubes are coils; Figure 4 This is a schematic diagram of a thermal storage system in some examples of the present invention.

[0024] In the diagram: 1-Closed thermal storage unit; 2-Storage body; 3-Heat exchange tube; 4-First end; 5-Second end; 6-Circulating pump; 7-Heat source; 8-Heat exchanger; 9-Pipeline; 11-Steel frame; 12-Plate; 91-Pipeline 1; 92-Pipeline 2; 93-Pipeline 3; 94-Pipeline 4; 95-Pipeline 5; 96-Pipeline 6; 97-Pipeline 7; 98-Pipeline 8; 99-Pipeline 9; A-Valve. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The purpose of this invention is to provide a thermal storage body, thermal storage system, and thermal storage and release process that takes into account the requirements of low cost, high thermal conductivity, modularity and versatility, and long-term thermal storage in all scenarios, and solves the problem of insufficient comprehensive performance of existing sandy thermal storage materials and equipment.

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Reference Figures 1-4 This embodiment provides a heat storage body 2, comprising a matrix powder and a thermally conductive modified powder. The matrix powder includes sand, and the thermally conductive modified powder includes graphite powder. The thermal conductivity of sand is 0.15–0.25 W / (m·K), and the thermal conductivity of graphite powder is 70–150 W / (m·K).

[0029] The working principle of the heat storage body 2 in this embodiment is as follows: The specific heat capacity of sand is 800 J / (kg·K), and its density is 1.4–1.5 t / m³. 3 It has a temperature resistance of ≤1300℃, a raw material price of approximately 60 yuan / ton, a specific heat capacity of 800 J / (kg·K), and a density of 0.6~0.8 t / m³. 3Temperature resistance ≤450℃.

[0030] Sand, as a matrix powder, is readily available and inexpensive, possessing stable heat storage capacity and able to store large amounts of thermal energy based on its specific heat capacity. However, its thermal conductivity is relatively weak, resulting in slow heat transfer within the heat storage body 2 when used alone, easily leading to excessively large local temperature differences and low heat charging and discharging efficiency. Graphite powder, with its high thermal conductivity, can be mixed with sand to create continuous thermal conduction pathways within the overall powder, significantly improving the overall thermal conductivity of the heat storage body 2. This accelerates heat conduction within the heat storage body 2, reduces temperature differences between different areas, and makes the heat storage and discharging process more uniform. Furthermore, the combination of the two can balance heat storage capacity and heat transfer efficiency, achieving a balance between operating costs and performance.

[0031] The materials used in the thermal storage body 2 are not limited to sand and graphite powder; they can also include other materials, thereby achieving corresponding performance optimization through the combination of multiple materials.

[0032] It should be noted that if the sand and graphite powder are not mixed evenly, the areas where graphite accumulates will conduct heat too quickly, while the areas without graphite will have slow heat transfer. This will result in significant differences in the heat exchange efficiency of the heat storage body 2 and will also cause heat accumulation. Long-term use will easily exacerbate local thermal stress losses in the pipeline. Therefore, in actual use, the sand and graphite powder must be mixed evenly so that the graphite particles are evenly dispersed in the gaps between the sand grains, forming continuous heat conduction channels everywhere. This avoids situations where there is local graphite accumulation or areas where there is no graphite at all, ensuring that the overall thermal conductivity of the heat storage body 2 remains consistent. During charging and discharging, the internal heat conduction speed is uniform, and there will be no temperature difference defects such as local high temperature and local low temperature.

[0033] In some examples, the mass ratio of sand to graphite powder is 90–97:3–10. The optimal ratio is 95:5, which significantly improves the thermal conductivity of the thermal storage body 2, results in high thermal density, and has relatively low overall material costs, making it more suitable for large-scale engineering applications.

[0034] This formulation range uses sand as the main raw material, which can reduce the overall production cost of thermal storage materials and ensure that thermal storage body 2 has sufficient thermal storage capacity. A small amount of graphite powder is evenly dispersed between sand particles to form a complete and continuous heat conduction network. This avoids the situation where the heat conduction path is broken and the heat transfer effect is insufficient due to insufficient graphite addition. It also limits the upper limit of graphite proportion to prevent excessive graphite usage from significantly increasing material costs. In addition, it can also avoid the problems of agglomeration and uneven local heat conduction caused by excessive graphite powder accumulation.

[0035] Reference Figures 1-4This embodiment also provides a thermal storage system, including the aforementioned thermal storage body 2, and a closed thermal storage unit 1, which houses the thermal storage body 2. A heat exchange pipe 3 passes through the closed thermal storage unit 1 and the thermal storage body 2, with its first end 4 and second end 5 located outside the closed thermal storage unit 1. One of the first end 4 and the second end 5 is used for the inflow of heat exchange medium, and the other is used for the outflow of heat exchange medium.

[0036] The working principle of the thermal storage system in this embodiment is as follows: The enclosed thermal storage unit 1 can completely enclose and house the thermal storage body 2, forming a sealed space. This reduces the outward loss of heat stored in the thermal storage body 2, lowers insulation losses, prevents rainwater and debris from entering and contaminating the thermal storage body 2, and avoids the leakage of thermal storage powder dust, ensuring the long-term stable operation of the system. The enclosed thermal storage unit 1 has a modular structure, can be independently deployed or assembled, has flexible and adjustable overall dimensions, and covers a wide range of energy storage thresholds.

[0037] The heat exchange tubes 3, arranged throughout the system, are completely embedded inside the heat storage body 2. The heat exchange medium can continuously circulate within the tubes, exchanging heat with the heat storage body 2. Both ends of the heat exchange tubes 3 extend outside the enclosed heat storage unit 1, facilitating connection to external heating and heat-using equipment. The circulation pattern of the medium flowing in from one end and out from the other continuously completes the heat exchange process of heat being stored in or removed from the heat storage body 2, achieving the storage and release of thermal energy. The entire heat storage system adopts an indirect heat exchange design; the heat exchange medium does not directly contact the heat storage body 2, and the two are separated by the tube walls of the heat exchange tubes 3. Valves A, such as shut-off valves, are typically installed at the first and second ends to control the operation.

[0038] In some examples, the enclosed thermal storage unit 1 is an above-ground metal container or an underground reinforced concrete pit.

[0039] For above-ground metal containers, they are easy to process and form, have good overall sealing, and are relatively lightweight, making them easy to hoist and install on-site. They are suitable for small to medium-sized distributed thermal storage scenarios, and their installation positions can be flexibly adjusted. For underground reinforced concrete pits, they rely on civil engineering structures to build large-capacity thermal storage spaces. The soil layer can help isolate heat from spreading outwards, resulting in more outstanding insulation effects. They are suitable for large-scale, long-term, and cross-seasonal thermal storage conditions. For above-ground metal containers, they can include square or cylindrical boxes and steel frames 11 for fixing and supporting the boxes. The boxes are assembled from plates 12.

[0040] The two structural forms can be flexibly selected according to site conditions and energy storage scale, thus broadening the applicable scenarios of the entire thermal storage system.

[0041] In some examples, heat exchange tube 3 is a coil, spiral tube, or serpentine tube.

[0042] The coils can extend fully within a planar space, ensuring uniform heat distribution and low fluid flow resistance. They are suitable for shallow, flat installations, guaranteeing consistent heat exchange across the planar area. The spiral tubes utilize a three-dimensional winding structure, maximizing the arrangement of heat exchange tubes within limited vertical space. This effectively increases the heat exchange contact area, improves overall heat charging and discharging efficiency, and ensures more uniform heat exchange between the upper and lower areas of the heat storage unit 2. The serpentine tube arrangement is neat and orderly, facilitating easy disassembly and maintenance. Its symmetrical and balanced layout enables large-scale uniform heat exchange, making it suitable for layered heat storage structures. In practical applications, the type of heat exchange tubes 3 can be flexibly selected based on the internal spatial structure of the heat storage unit 1 and the required energy storage power.

[0043] The heat exchange tube 3 is preferably made of 20# seamless steel pipe or stainless steel pipe. The pipeline can be arranged in layers, vertically or in a multi-point distributed manner. The pipelines can be connected in series or in parallel in sections.

[0044] In some examples, the heat exchange medium is heat transfer oil, molten salt, or antifreeze.

[0045] Heat transfer oil offers excellent thermal stability and flow properties, making it suitable for medium- and low-temperature thermal storage scenarios. It is not prone to vaporization loss and can be used continuously for extended periods. Molten salt boasts high operating temperature and thermal density, making it suitable for high-temperature thermal storage conditions and capable of meeting the heat exchange cycle requirements of high-power, high-energy storage. Antifreeze exhibits excellent low-temperature performance, preventing pipe freezing and blockage in low-temperature environments, and is suitable for outdoor and low-temperature systems. The selection of these three media options allows the thermal storage system to stably complete heat transfer and exchange under different temperatures and operating conditions.

[0046] In some examples, temperature sensors, pressure sensors, and flow sensors are installed at both the first end 4 and the second end 5.

[0047] Temperature sensors accurately collect the temperature difference between the inlet and outlet of the medium, thereby determining the real-time charging and discharging status and heat exchange efficiency of the thermal storage system. Pressure sensors monitor changes in the internal pressure of the medium throughout the pipeline, promptly identifying potential faults such as pipeline blockage, abnormal pressure, and leaks, preventing equipment damage caused by high-pressure overload or low-pressure anomalies. Flow sensors accurately monitor the circulating flow rate of the medium, ensuring stable and balanced heat exchange circulation.

[0048] Multi-dimensional sensing and monitoring work together to achieve data acquisition, enabling real-time feedback of system operating parameters. This allows staff to accurately control the system's operating conditions, achieving precise and intelligent management of the heat storage and release process. It effectively improves the operational safety and stability of the entire heat storage system and extends the service life of the equipment.

[0049] In some examples, the thermal storage system also includes a heat source 7, which is connected to the first end 4 and the second end 5 to establish a thermal storage circulation loop.

[0050] The heat source 7 and the heat exchange tube 3 are connected at both ends to form an independent heat storage circulation loop, which can effectively collect external low-grade surplus heat energy such as solar energy and industrial waste heat, and transfer the collected heat to the heat exchange medium flowing in the loop. The heated heat exchange medium flows through the heat exchange tube 3 inside the heat storage body 2, and the heat is continuously transferred and stored in the heat storage body 2 through heat exchange, thus fully realizing the process of external heat energy recovery, transfer and storage.

[0051] The closed-loop thermal storage circuit ensures stable circulation of the heat exchange medium, reduces heat loss and leakage, continuously heats the thermal storage body 2, effectively utilizes idle waste heat and renewable thermal energy, improves energy efficiency, and allows the system to complete thermal storage operations autonomously without relying on traditional energy sources for heating, significantly reducing system operating energy consumption and operating costs.

[0052] In some examples, the thermal storage system also includes a heat exchanger 8, which is connected to the first end 4 and the second end 5 respectively to establish a heat release circulation loop.

[0053] The heat exchanger 8 and heat exchange tube 3 are connected at both ends to form an independent heat release circulation loop. When external heat supply is required, the heat exchange medium flowing in the loop can pass through the heat storage body 2 to absorb the stored heat. The medium carrying the heat energy is transported to the interior of the heat exchanger 8, and the heat is transferred to the terminal medium such as heating or industrial heat through the heat exchange interface, thus completing the external supply of heat energy. The heat release circulation loop and the heat storage circulation loop do not work simultaneously. The heat release process can be started and stopped separately according to the actual heat demand without activating the heat storage pipeline on the heat source 7 side, allowing for flexible control.

[0054] The heat storage circulation loop and the heat release circulation loop can use the same circulation pump 6, or they can each be configured with a separate circulation pump 6.

[0055] For specific details on the form of the thermal storage system, please refer to Figure 4 . Figure 4 The diagram shows multiple pipes 9. The outlet of heat source 7 is connected to the first end 4 of heat exchange tube 3 via pipes 1 (91) and 2 (92). The inlet of heat source 7 is connected to the outlet of heat exchanger 8 via pipes 3 (93), 4 (94), and 5 (95). The second end 5 of heat exchange tube 3 is connected to the inlet of heat exchanger 8 via pipes 7 (97) and 8 (98). One end of pipe 6 (96) merges with pipes 1 (91) and 2 (92) at a point, and the other end of pipe 6 (96) merges with pipes 3 (93) and 4 (94) at a point. One end of pipe 9 (99) merges with pipes 7 (97) and 8 (98) at a point, and the other end of pipe 9 (99) merges with pipes 4 (94) and 5 (95) at a point.

[0056] Figure 4In the process, when valve A on pipeline 1 (91), pipeline 2 (92), pipeline 7 (97), pipeline 9 (99), pipeline 4 (94), and pipeline 3 (93) is open, and valve A on pipeline 5 (95), pipeline 6 (96), and pipeline 8 (98) is closed, the thermal storage system is in the thermal storage cycle process.

[0057] Figure 4 In the process, when valve A on pipelines 7 (97), 8 (98), 5 (95), 4 (94), 96, and 2 (92) is open, and valve A on pipelines 1 (91), 3 (93), and 9 (99) is closed, the heat storage system is in a heat release cycle process.

[0058] Reference Figures 1-4 This embodiment also provides a heat storage and release process using the aforementioned heat storage system, comprising the following steps: S1 Heat storage stage: the heat storage circulation loop is opened, and the heat exchange medium absorbs heat through the heat source 7 and flows through the heat exchange tube 3 to store heat in the heat storage body 2. S2 Heat preservation stage: the heat storage circulation loop is closed, and static heat storage is achieved by relying on the sealed heat storage unit 1 for heat preservation. S3 Heat release stage: the heat release circulation loop is opened, and the heat exchange medium carries away the heat from the heat storage body 2 and delivers it to the heat exchanger 8 for external heat supply.

[0059] The working principle of the heat storage and release process in this embodiment is as follows: This thermal energy storage and release process relies on a supporting thermal energy storage system to achieve phased and orderly operation. Each step is seamlessly connected and clearly defined, ensuring stable storage, sealing, and release of thermal energy. In the thermal storage stage, the thermal energy storage circulation loop is opened, allowing the heat exchange medium to continuously flow through the heat source 7 to absorb external renewable thermal energy or surplus waste heat. The heat-carrying medium flows through the heat exchange pipe 3 into the interior of the thermal storage body 2, and through sufficient heat conduction, the heat is evenly stored in the sand, achieving effective recovery and storage of clean energy and waste heat, alleviating energy waste. In the insulation stage, the thermal energy storage circulation loop is closed to stop dynamic heat exchange. The sealed insulation structure of the enclosed thermal storage unit 1 isolates internal and external heat exchange, maximizing the suppression of heat loss from the thermal storage body 2, achieving long-term static constant-temperature thermal energy storage, and meeting the needs of delayed heat use and cross-period energy storage. In the heat release stage, the circulation loop is reopened, using the flow of the heat exchange medium to carry away the thermal energy stored inside the thermal storage body 2, and transporting the high-temperature medium to the heat exchanger 8 to complete the heat energy conversion, providing stable external heat supply, and achieving controllable release and efficient utilization of thermal energy. The entire process is simple, controllable, and stable in operation. It can flexibly switch between heat storage, insulation, and heat release states according to heat demand, effectively realizing peak-shifting storage and on-demand supply of thermal energy, significantly improving energy utilization efficiency, and adapting to the energy storage and heating needs of various scenarios.

[0060] Before the entire system is put into operation, a complete commissioning process must be completed: install all pipelines and sensing equipment, conduct pipeline pressure tests and sensor signal calibration, and record the initial temperatures of the heat storage body 2, heat exchange medium, and environment; repeat the heat storage, heat preservation, and heat release cycles 3 to 5 times to verify the long-term operational stability and performance degradation level of the system.

[0061] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A heat storage body (2), characterized in that: The material includes a matrix powder and a thermally conductive modified powder. The matrix powder includes sand, and the thermally conductive modified powder includes graphite powder. The thermal conductivity of the sand is 0.15 to 0.25 W / (m·K), and the thermal conductivity of the graphite powder is 70 to 150 W / (m·K).

2. The heat storage body (2) according to claim 1, characterized in that: The mass ratio of the sand to the graphite powder is 90-97:3-10.

3. A thermal storage system, characterized in that, Including the thermal storage body (2) as described in any one of claims 1 or 2, further comprising: A closed thermal storage unit (1) is used to house the thermal storage body (2). The heat exchange tube (3) passes through the closed heat storage unit (1) and the heat storage body (2), and its first end (4) and second end (5) are located outside the closed heat storage unit (1); one of the first end (4) and the second end (5) is used to flow into the heat exchange medium, and the other is used to flow out of the heat exchange medium.

4. The thermal storage system according to claim 3, characterized in that: The enclosed thermal storage unit (1) is an above-ground metal container or an underground reinforced concrete foundation pit.

5. The thermal storage system according to claim 3, characterized in that: The heat exchange tube (3) is a coil, a spiral tube, or a serpentine tube.

6. The thermal storage system according to claim 3, characterized in that: The heat exchange medium is heat transfer oil, molten salt, or antifreeze.

7. The thermal storage system according to claim 3, characterized in that: Temperature sensor, pressure sensor and flow sensor are installed at both the first end (4) and the second end (5).

8. The thermal storage system according to claim 3, characterized in that, Also includes: Heat source (7) is connected to the first end (4) and the second end (5) respectively to establish a heat storage circulation loop.

9. The thermal storage system according to claim 3, characterized in that, Also includes: The heat exchanger (8) is connected to the first end (4) and the second end (5) respectively to establish a heat release circulation loop.

10. A heat storage and release process, characterized in that, Using the thermal storage system as described in any one of claims 3 to 9, the following steps are included: S1 Thermal storage stage, the thermal storage circulation loop is opened, the heat exchange medium absorbs heat through the heat source (7) and flows through the heat exchange tube (3) to store heat in the thermal storage body (2); S2 Heat preservation stage, the thermal storage circulation loop is cut off, and static thermal storage is achieved by relying on the closed thermal storage unit (1) for heat preservation; S3 Heat release stage, the heat release circulation loop is opened, the heat exchange medium carries away the heat of the thermal storage body (2) and delivers it to the heat exchanger (8) for external heat supply.

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