Magnesium oxide-based composite material coupling coil pipe heat storage device

Abstract

The invention belongs to the technical field of magnesium oxide-based heat storage devices, and particularly discloses a magnesium oxide-based composite material coupling coil pipe heat storage device which comprises an outer shell, a heat preservation layer, a high-temperature heat insulation lining and a transverse supporting ring, the heat preservation layer is arranged on the inner side of the outer shell, and the high-temperature heat insulation lining is arranged on the inner side of the heat preservation layer; a magnesium oxide-based gradient composite packed bed is arranged in the high-temperature heat-insulating lining, a spiral coil bundle is arranged in the magnesium oxide-based gradient composite packed bed, a plurality of transverse supporting rings which are uniformly distributed are arranged on the outer side of the outer shell, and a thermocouple array and a pressure sensor are arranged on the outer side of the high-temperature heat-insulating lining. According to the magnesium oxide-based composite material coupling coil pipe heat storage device, the integrated structural design that the porous magnesium oxide framework is doped with the high-heat-conduction material in a gradient mode and the spiral coil pipe reinforcing ribs is adopted, and direct transfer and efficient storage of heat on a fluid-solid interface are achieved through a dynamic direct heat coupling method of a molten salt medium and a heat storage material; and a complicated heat exchanger structure is not involved.

Description

Technical Field

[0001] The present invention relates to the technical field of magnesium oxide-based heat storage devices, and in particular to a magnesium oxide-based composite material coupled coil heat storage device. Background Art

[0002] With the rapid development of concentrated solar thermal power generation and high-temperature industrial waste heat utilization technologies, traditional heat storage media (such as molten salt and concrete) have exposed bottlenecks such as insufficient heat storage density, high-temperature corrosion, and short cycle life. In contrast, magnesium oxide (MgO) has a sensible heat storage capacity of up to 1.5 times the baseline value of molten nitrate salt. Its high-temperature stability enables long-term operation at 1000°C without the risk of phase change decomposition. Its gradient-matched thermal expansion coefficient ensures stable thermal cycling and excellent thermal shock resistance. Its chemical inertness effectively mitigates the corrosion and leakage risks of molten salt systems. Furthermore, magnesium oxide combines abundant raw materials, environmental friendliness (zero toxic emissions), and lifecycle cost advantages. These breakthrough properties have made magnesium oxide a key next-generation material for high-temperature heat storage.

[0003] Despite the inherent theoretical advantages of magnesium oxide-based heat storage technology, its current industrialization process faces multiple technical bottlenecks: First, direct electric heating devices suffer from the core flaw of low electricity-to-heat conversion efficiency; second, indirect coupling devices have a prolonged response time and significant heat loss due to multi-stage heat exchange; third, traditional gradient heat storage devices are forced to add redundant structures to compensate for thermal resistance effects, and microchannel devices, while improving heat exchange efficiency, significantly increase manufacturing costs. These technical shortcomings make it difficult for existing solutions to meet the needs of large-scale application in terms of energy efficiency indicators, dynamic response, and economic efficiency.

[0004] To address these issues, the present invention proposes a heat storage device based on a magnesium oxide-based composite coupled coil. This device utilizes a porous magnesium oxide framework gradiently doped with a high-thermal-conductivity material, integrated with spiral coil reinforcement ribs. Through dynamic direct thermal coupling between the molten salt medium and the heat storage material, heat is directly transferred and efficiently stored at the fluid-solid interface, eliminating the need for complex heat exchanger structures. Due to its simple structure, dynamic adjustability, high reliability, short thermal response time, and high-temperature adaptability, this device enables rapid, high-capacity heat storage. Summary of the Invention

[0005] The present invention aims to provide a magnesium oxide-based composite material coupled coil heat storage device. This device utilizes a porous magnesium oxide framework gradiently doped with a high-thermal-conductivity material and an integrated structure with spiral coil reinforcement ribs. Through dynamic direct thermal coupling between the molten salt medium and the heat storage material, heat is directly transferred and efficiently stored at the fluid-solid interface, eliminating the need for complex heat exchanger structures. Due to its simple structure, dynamic adjustability, high reliability, short thermal response time, and high-temperature adaptability, this device enables rapid and high-capacity heat storage.

[0006] To achieve the above-mentioned objectives, the present invention provides a magnesium oxide-based composite material coupled coil heat storage device, comprising an external shell, an insulation layer, a high-temperature thermal insulation lining, and a transverse support ring. An insulation layer is provided on the inner side of the external shell, a high-temperature thermal insulation lining is provided on the inner side of the insulation layer, a magnesium oxide-based gradient composite filler bed is provided in the high-temperature thermal insulation lining, a spiral coil bundle is provided inside the magnesium oxide-based gradient composite filler bed, a plurality of evenly distributed transverse support rings are provided on the outer side of the external shell, a thermocouple array and a pressure sensor are provided on the outer side of the high-temperature thermal insulation lining, the thermocouple array is used to measure the temperature change of the magnesium oxide-based gradient composite filler bed, and the pressure sensor is used to measure the pressure change of the magnesium oxide-based gradient composite filler bed.

[0007] Preferably, the insulation layer is divided into four layers from outside to inside according to thickness: refractory bricks, phase change materials, ceramic fibers, and microporous insulation boards.

[0008] Preferably, the high-temperature thermal insulation lining is composed of a ceramic fiber-based composite material and a microporous thermal insulation board.

[0009] Preferably, an inner tube rib reinforcement structure is provided inside the spiral coil tube bundle, and the inner tube rib reinforcement structure includes a surface layer inner tube rib reinforcement structure array, a transition layer inner tube rib reinforcement structure array, and a core layer inner tube rib reinforcement structure array.

[0010] Preferably, the magnesium oxide-based gradient composite filler bed comprises a surface layer of composite particles, a transition layer of porous material, and a core layer of porous magnesium oxide (MgO).

[0011] Preferably, the transverse support ring adopts a corrugated expansion joint design and is pre-tightened with high-strength bolts through a preset thermal expansion gap.

[0012] Preferably, a salt inlet direct current pipeline is provided above the spiral coil tube bundle, and the salt inlet direct current pipeline is connected with the spiral coil tube bundle through a flow guide cover.

[0013] Preferably, the deflector cover includes a conical top structure and internal deflection grooves, and the conical top structure is provided with a plurality of deflection grooves.

[0014] The advantages and beneficial effects of the present invention using the above-mentioned magnesium oxide-based composite material coupled coil heat storage device are: 1. This invention utilizes a porous magnesium oxide-based gradient composite thermal storage material, significantly improving its thermal conductivity and achieving high thermal energy storage density, significantly outperforming traditional molten salt or phase change materials. High-efficiency thermal storage is achieved through direct contact heat transfer and layered composite thermal storage (surface layer, transition layer, core layer).

[0015] 2. The heat storage device of the present invention has a simple structure. Compared with the existing mainstream magnesium oxide (MgO)-based heat storage system, it does not require an additional heat exchanger structure, occupies a small space, and has more flexible usage scenarios. It adopts a design of direct heating of spiral coils and a multi-stage adjustable tube rib reinforcement structure array to induce vortex flow, taking into account high Reynolds number turbulence enhancement, achieving faster heat charging response, and is also suitable for low pump power requirements.

[0016] 3. The gradient composite filler bed designed in the present invention sequentially reduces the difference in thermal expansion coefficient of materials, effectively disperses stress concentration, and improves thermal shock cycle resistance and cycle life. It has a modular and scalable design. After verification on a pilot scale, it can be scaled up to large industrial heat storage tanks, maintaining similar thermodynamic and mechanical properties, and operating reliably and safely. It is equipped with auxiliary devices such as lateral support rings, deflectors, thermocouple arrays, and pressure sensors to achieve thermal expansion control, uniform flow rate distribution, and online temperature and pressure monitoring, effectively preventing thermal shock and structural instability.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic structural diagram of a magnesium oxide-based composite material coupled coil heat storage device of the present invention; Figure 2 This is a schematic diagram of the structure of a flow guide cover in a magnesium oxide-based composite material coupled coil heat storage device of the present invention; Figure 3 This is a schematic diagram of the inner tube rib reinforcement structure in a magnesium oxide-based composite material coupled coil heat storage device of the present invention; Figure 4 This is a schematic diagram of a spiral coil bundle and a magnesium oxide-based gradient composite filler bed in a magnesium oxide-based composite coupled coil heat storage device of the present invention; Figure 5 This is a schematic diagram of a magnesium oxide-based gradient composite filler bed in a magnesium oxide-based composite material coupled coil heat storage device of the present invention; Figure 6 It is a schematic diagram of the flow of molten salt and related heat flow direction inside the magnesium oxide-based composite material coupled coil heat storage device of the present invention.

[0019] Reference numerals 1. External shell; 2. Insulation layer; 3. High-temperature insulation lining; 4. Horizontal support ring; 5. High-temperature molten salt; 5-1. Inlet straight pipe high-temperature molten salt; 5-2. Surface layer high-temperature molten salt; 5-3. Transition layer medium-high temperature molten salt; 5-4. Core layer medium-low temperature molten salt; 5-5. Outlet straight pipe low-temperature molten salt; 6. Flow inlet regulating valve; 7. Salt inlet pipe flange; 8. Salt inlet direct current pipe; 9. Flow guide cover; 9-1. Conical top structure; 9-2. Flow guide groove; 10. Spiral coil bundle; 1 1. Rib reinforcement structure inside the tube; 11-1. Array of rib reinforcement structure inside the surface tube; 11-2. Array of rib reinforcement structure inside the transition layer tube; 11-3. Array of rib reinforcement structure inside the core layer tube; 12. Magnesium oxide-based gradient composite filler bed; 12-1. Composite particles on the surface layer; 12-2. Porous material on the transition layer; 12-3. Porous magnesium oxide on the core layer; 13. Thermocouple array; 14. Pressure sensor; 15. Salt outlet direct current pipeline; 16. Salt outlet pipe flange; 17. Flow outlet regulating valve. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons of ordinary skill in the field to which the present invention belongs. The words "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0022] Example 1 like Figure 1As shown, a magnesium oxide-based composite material coupled coil heat storage device includes an outer shell 1, an insulation layer 2, a high-temperature thermal insulation lining 3, and a transverse support ring 4. The outer shell 1 is provided with an insulation layer 2, the inner side of the insulation layer 2 is provided with a high-temperature thermal insulation lining 3, the high-temperature thermal insulation lining 3 is provided with a magnesium oxide-based gradient composite filler bed 12, the magnesium oxide-based gradient composite filler bed 12 is provided with a spiral coil bundle 10, the outer side of the outer shell 1 is provided with a plurality of evenly distributed transverse support rings 4, the outer side of the high-temperature thermal insulation lining 3 is provided with a thermocouple array 13 and a pressure sensor 14, the thermocouple array 13 is used to measure the temperature change of the magnesium oxide-based gradient composite filler bed 12, and the pressure sensor 14 is used to measure the pressure change of the magnesium oxide-based gradient composite filler bed 12.

[0023] Flow control valves (including an inlet flow control valve 6 and an outlet flow control valve 17) and a salt inlet flange 7 are located above the spiral coil bundle 10. A salt outlet straight pipe 15 and a salt outlet flange 16 are located at the bottom. High-temperature molten salt 5 flows within the spiral coil bundle 10 and is divided into an inlet straight pipe high-temperature molten salt 5-1, a surface layer high-temperature molten salt 5-2, a transition layer medium-high-temperature molten salt 5-3, a core layer medium-low-temperature molten salt 5-4, and an outlet straight pipe low-temperature molten salt 5-5.

[0024] The insulation layer 2 is divided into four layers from the outside to the inside according to thickness: refractory bricks, phase change materials, ceramic fibers, and microporous insulation boards.

[0025] The high-temperature heat-insulating lining 3 is composed of a ceramic fiber-based composite material and a microporous heat-insulating board.

[0026] An inner tube rib reinforcement structure 11 is provided inside the spiral coil tube bundle 10. The inner tube rib reinforcement structure 11 includes a surface inner tube rib reinforcement structure array 11-1, a transition layer inner tube rib reinforcement structure array 11-2, and a core layer inner tube rib reinforcement structure array 11-3.

[0027] The magnesium oxide-based gradient composite filler bed 12 includes a surface layer of composite particles 12 - 1 , a transition layer of porous material 12 - 2 , and a core layer of porous magnesium oxide 12 - 3 .

[0028] The transverse support ring 4 adopts a corrugated expansion joint design and is pre-tightened by a preset thermal expansion gap and high-strength bolts.

[0029] A salt inlet direct current pipeline 8 is provided above the spiral coil tube bundle 10 , and the salt inlet direct current pipeline 8 is connected to the spiral coil tube bundle 10 through a flow guide cover 9 .

[0030] The deflector 9 includes a conical top knot 9-1 and a deflection groove 9-2, and a plurality of deflection grooves 9-2 are provided on the conical top knot 9-1.

[0031] The outer shell 1 can be constructed of API 650 carbon steel or other engineering materials meeting pressure requirements. It provides overall structural support and sealing protection, capable of withstanding the internal high-temperature molten salt pressure 5 and external wind, snow, and earthquake loads. There are no mandatory restrictions on the shell's height-to-diameter ratio; either a short and stout shell (height-to-diameter ratio H / D < 1.5) or a slender shell (height-to-diameter ratio H / D ≥ 1.5) can be optimized based on site conditions. The insulation layer 2 features a nested ring structure and is divided into four layers, from outer to inner, based on thickness: refractory bricks, phase change material, ceramic fiber, and microporous insulation board. The high-temperature insulation lining 3, composed of a ceramic fiber-based composite material and microporous insulation board, offers thermal shock resistance and long-term high-temperature stability, protecting and insulating the tank structure. The ceramic fiber provides structural support and thermal shock resistance, while the microporous insulation board enhances thermal insulation at high temperatures, making it ideally suited for the operating environment of magnesium oxide-based thermal storage devices (involving medium- and high-temperature heat storage, ranging from 500-1000°C). The transverse support ring 4 utilizes a bellows expansion joint design. By pre-setting thermal expansion clearances and pre-tightening high-strength bolts, this ensures radial rigidity and axial thermal displacement compensation for the shell under extreme operating conditions, preventing thermal expansion instability. The inlet, straight pipeline, high-temperature molten salt 5-1 is first transported through an external circulation pipeline. After flow control is achieved by the flow inlet regulating valve 6, it enters the salt inlet pipe flange 7 connected to the top of the heat storage device. The salt inlet direct current pipeline 8 is set according to the heat storage device's no-load volume threshold (≥15% of the total volume) to ensure sufficient flow of the high-temperature molten salt 5.

[0032] like Figure 2 As shown, the flow deflector 9 utilizes a removable trough structure, including a conical top junction 9-1 that initially diffuses the fluid and creates a radial guide. Several internal flow guide grooves 9-2 are defined on the conical surface to divide the fluid, forming multiple equal branches. The groove height and width are adjusted to match the molten salt flow rate, achieving uniform distribution of the molten salt. The spiral coil bundle 10 serves as the main heat transfer channel within the high-temperature molten salt 5 thermal storage device, constraining the internal operating path. It utilizes a corrosion-resistant coating material (such as a SiC-Cr composite coating) to enhance corrosion resistance. Its size can be dynamically adjusted based on the tank size and packing bed height.

[0033] like Figure 3 As shown, an inner rib reinforcement structure 11 is formed on the inner wall of the coil by extrusion or welding technology. Raised spiral ribs are used (axial, annular, grooved spiral or combined ribs are optional). The inner rib reinforcement structure 11 is inclined along the flow direction of the molten salt fluid in the spiral coil bundle 10. The number, size and spacing of the ribs are dynamically configured according to the requirements of the heat storage stage, focusing on balancing pressure drop and heat transfer efficiency.

[0034] like Figure 4As shown, the inner tube rib reinforcement structure 11 is divided into a surface layer inner tube rib reinforcement structure array 11-1, a transition layer inner tube rib reinforcement structure array 11-2, and a core layer inner tube rib reinforcement structure array 11-3 according to the gradient material distribution of the heat storage device. It is worth noting that the inner tube rib reinforcement structure 11 can be based on the following Figure 5 The multi-layer filling structure of the magnesium oxide-based gradient composite filler bed 12 is arranged in a single stage (or multiple stages), such as only in Figure 6 The surface composite particles 12-1 are arranged in the high thermal conductivity area of the pipe section (the high thermal conductivity area corresponds to the surface high-temperature molten salt 5-2), inducing secondary eddy currents to enhance surface heat exchange, which is suitable for scenarios sensitive to pressure drop (or arranged simultaneously in three layers of heat storage materials, suitable for high pump power and high heat dissipation scenarios). The surface tube inner rib reinforcement structure array 11-1 (or the transition layer tube inner rib reinforcement structure array 11-2, the core layer tube inner rib reinforcement structure array 11-3) is in the same direction and pitch as the outer spiral coil tube bundle 10 curve, forming a double spiral channel, which not only destroys the molten salt boundary layer, but also forms a secondary flow effect to induce strong eddy currents. This will greatly increase the heat exchange between the high-temperature molten salt 5 and the surface high-thermal conductivity heat storage material, quickly store the heat in the surface composite particles 12-1, and then the heat will use the transition layer porous material 12-2 as a thermal stress buffer zone (the buffer zone corresponds to the transition layer medium- and high-temperature molten salt 5-3), and efficiently and stably transfer the double heat (from the high thermal conductivity zone and the transition layer medium- and high-temperature molten salt 5-3) to the core layer porous MgO in the high-capacity heat zone (the high-capacity zone corresponds to the core layer medium- and low-temperature molten salt 5-4). The core layer porous MgO will store the double heat (from the thermal stress buffer zone and the core layer medium- and low-temperature molten salt 5-4).

[0035] The gradient thickness ratio of the composite layer of the magnesium oxide-based gradient composite filler bed 12 is adjusted by measuring the temperature and pressure gradients using a thermocouple array 13 and a pressure sensor 14. However, the core layer's porous MgO thickness must account for at least 50% to ensure sufficient heat storage capacity. After sufficient heat exchange with the heat storage material, the low-temperature molten salt in the outlet straight pipe 5-5 is regulated and monitored by a flow outlet regulating valve 17 before flowing into the salt outlet direct pipe 15 and being discharged to the external circulation system through a salt outlet pipe flange 16 connected to the side wall.

[0036] During operation, the inlet straight pipe high-temperature molten salt 5-1 is transported through an external circulation pipeline, and after flow control is completed by the flow inlet regulating valve 6, it flows into the salt inlet pipe flange 7 connected to the top of the storage tank. The molten salt then flows through the salt inlet straight pipe 8 and fully develops before reaching the deflector 9. The inlet straight pipe high-temperature molten salt 5-1 is evenly distributed to the spiral coil bundle 10 through the internal guide groove 9-2. Inside the coil, molten salts at different temperature stages (surface high-temperature molten salt 5-2, transition layer medium-high-temperature molten salt 5-3, core layer medium-low-temperature molten salt 5-4) flow in the double spiral channel formed by the inner rib spiral fins (inner channel) of the inner rib reinforcement structure array and the outer spiral curve (outer channel). This induces strong vortexes and secondary flows, causing the boundary layer to continuously peel off and redevelop, significantly improving the convective heat transfer coefficient. Under the action of three-dimensional spiral mixed flow, the molten salt performs gradient heat exchange with the magnesium oxide-based gradient composite filler bed 12, and fully exchanges heat with the high thermal conductivity area of the surface composite particles 12-1, the transition layer porous material 12-2, and the core layer porous MgO. The temperature of the molten salt changes from the initial high temperature to medium-high temperature, medium-low temperature, and then to low temperature.

[0037] The guide cover 9 includes a conical top junction 9-1 and a guide groove 9-2. The conical top junction 9-1 allows the fluid to diffuse from the center to the edge, forming a radial distribution. Its function is to evenly guide the high-temperature molten salt 5 entering from the top along the circumferential direction to prevent it from rushing directly to the bottom and causing local overheating. The internal guide groove 9-2 is symmetrically arranged to guide the molten salt to the inlet of the spiral coil bundle 10 below. Its functions are: (1) to enhance fluid disturbance and promote heat exchange. (2) to achieve layered diversion and avoid thermal shock.

[0038] The internal rib reinforcement structure 11 (surface layer internal rib reinforcement structure array 11-1, transition layer internal rib reinforcement structure array 11-2, and core layer internal rib reinforcement structure array 11-3) can be dynamically configured in multiple stages based on the layered structure of the magnesium oxide-based gradient composite filler bed 12, such as dense surface ribs, sparse transition layer ribs, and basic core layer ribs. This structure meets the flow and heat transfer requirements of different scenarios (reducing pressure drop or achieving high pumping power and heat dissipation). Simultaneously, the salt inlet and outlet direct current pipeline 8 (or salt outlet and direct current pipeline 15) maintains a smooth inner wall, eliminating local flow resistance and ensuring that the high-temperature molten salt 5 (or medium- and low-temperature molten salt) can fully develop and flow into (or out of) the storage tank, minimizing the pressure drop resistance caused by the ribs.

[0039] The magnesium oxide-based gradient composite filler bed 12 absorbs heat from the molten salt at different temperature stages and stores it in a gradient manner, achieving efficient heat storage. Finally, the flow rate outlet regulating valve 17 adjusts and monitors the flow rate of the low-temperature molten salt 5-5 in the outlet straight pipe. The flow first passes through the salt outlet direct current pipe 15 and then is discharged to the external circulation system through the salt outlet pipe flange 16.

[0040] During the entire heat storage process, a safety monitoring system is equipped, including a thermocouple array 13, a pressure sensor 14, etc. When local overtemperature or abnormal pressure drop is detected, the valve adjustment and safety pressure relief mechanism are automatically triggered to ensure efficient and safe heat storage.

[0041] Therefore, the present invention utilizes the aforementioned magnesium oxide-based composite material coupled coil heat storage device, employing a porous magnesium oxide framework gradiently doped with a high-thermal-conductivity material and an integrated structure with spiral coil reinforcement ribs. Through dynamic direct thermal coupling between the molten salt medium and the heat storage material, heat is directly transferred and efficiently stored at the fluid-solid interface, eliminating the need for complex heat exchanger structures. Due to its simple structure, dynamic adjustability, high reliability, short thermal response time, and high-temperature adaptability, this device enables rapid and high-capacity heat storage.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A magnesium oxide-based composite material coupled coil heat storage device, characterized in that: It includes an external shell, an insulation layer, a high-temperature thermal insulation lining, and a transverse support ring. The inner side of the external shell is provided with an insulation layer, the inner side of the insulation layer is provided with a high-temperature thermal insulation lining, the high-temperature thermal insulation lining is provided with a magnesium oxide-based gradient composite filler bed, the interior of the magnesium oxide-based gradient composite filler bed is provided with a spiral coil bundle, the outer side of the external shell is provided with multiple evenly distributed transverse support rings, the outer side of the high-temperature thermal insulation lining is provided with a thermocouple array and a pressure sensor, the thermocouple array is used to measure the temperature change of the magnesium oxide-based gradient composite filler bed, and the pressure sensor is used to measure the pressure change of the magnesium oxide-based gradient composite filler bed.

2. The magnesium oxide-based composite material coupled coil heat storage device according to claim 1, characterized in that: The thermal insulation layer is divided into four layers from outside to inside according to thickness: refractory bricks, phase change materials, ceramic fibers, and microporous thermal insulation boards.

3. The magnesium oxide-based composite material coupled coil heat storage device according to claim 1, characterized in that: The high-temperature heat-insulating lining is composed of a ceramic fiber-based composite material and a microporous heat-insulating board.

4. The magnesium oxide-based composite material coupled coil heat storage device according to claim 1, characterized in that: The spiral coil tube bundle is provided with an inner tube rib reinforcement structure, which includes a surface layer inner tube rib reinforcement structure array, a transition layer inner tube rib reinforcement structure array, and a core layer inner tube rib reinforcement structure array.

5. The magnesium oxide-based composite material coupled coil heat storage device according to claim 1, characterized in that: The magnesium oxide-based gradient composite filler bed comprises surface composite particles, a transition layer of porous material, and a core layer of porous magnesium oxide.

6. The magnesium oxide-based composite material coupled coil heat storage device according to claim 1, characterized in that: The transverse support ring adopts a corrugated expansion joint design and is pre-tightened by a preset thermal expansion gap and high-strength bolts.

7. The magnesium oxide-based composite material coupled coil heat storage device according to claim 1, characterized in that: A salt inlet direct current pipeline is provided above the spiral coil tube bundle, and the salt inlet direct current pipeline is communicated with the spiral coil tube bundle through a flow guide cover.

8. The magnesium oxide-based composite material coupled coil heat storage device according to claim 7, characterized in that: The deflector cover comprises a conical top structure and a deflection groove, and the conical top structure is provided with a plurality of deflection grooves.

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