Valley electricity steam heat storage energy storage equipment

Abstract

The invention relates to the technical field of heat storage equipment, in particular to valley electricity steam heat storage energy storage equipment which comprises a heating tank and a heat storage tank, a composite phase change energy storage medium and inert gas are arranged in the heating tank, and the valley electricity steam heat storage energy storage equipment further comprises an electrode stem, a heat pipe, a floating assembly, a floating block and a gas guide assembly. The composite phase change energy storage medium is heated when valley electricity is introduced into the electrode stem, the heat pipe penetrates through the heat storage tank, the evaporation section is immersed in the composite phase change energy storage medium, and when the composite phase change energy storage medium is heated and melted, the heat pipe transmits heat from the evaporation section to the condensation section and heats water in the heat storage tank. By arranging the heat pipe, the floating block, the floating assembly and the gas guide assembly, the composite phase change energy storage medium is stirred by utilizing fluctuation of water flow during electric-heat conversion, and inert gas in the heating tank is guided into the composite phase change energy storage medium, so that a thermocline is prevented from being generated, and the heat storage efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of thermal energy storage equipment, specifically a valley electricity steam thermal energy storage device. Background Technology

[0002] In the smart grid industry, thermal energy storage devices are often chosen to store off-peak electricity due to multiple economic and technical considerations. Among them, thermal energy storage devices are widely used because of their advantage of being able to absorb unstable and highly volatile renewable electricity. The core principle is to store energy through a thermal energy storage heater, which is a heater that stores thermal energy in a thermal energy storage material for later release.

[0003] Traditional thermal storage equipment includes two types: dual-tank and single-tank. However, both require large tanks to store molten salt. Although the tanks have thick insulation layers, their large surface area (including the top and walls) creates a huge radiator, resulting in static heat loss. This causes heat to continuously dissipate from the tank to the surrounding environment, affecting thermal storage efficiency. To address this issue, existing technologies offer relatively good solutions, such as the molten salt storage tank and molten salt electrothermal long-term energy storage device disclosed in CN114111044B. This energy storage device, combined with a supercritical carbon dioxide generator, forms a novel and efficient "electric-thermal-electric" technology mode, achieving large-capacity long-term energy storage and effectively improving thermal storage efficiency. However, the following drawbacks still exist: molten salt has poor thermal conductivity in its solid state, and heat transfer is slow during the transition from solid to molten state. This easily leads to a significant temperature gradient, or "temperature gradient layer," at the solid-liquid interface, limiting the electrothermal conversion efficiency and severely affecting the overall thermal storage efficiency.

[0004] Therefore, in order to solve the above problems, a valley electricity steam thermal energy storage device is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a valley-electricity steam thermal energy storage device that solves the problem that a temperature gradient layer in the molten salt within the heating tank severely limits the electrothermal conversion efficiency and affects the thermal storage efficiency. By incorporating heat pipes, floats, floating components, and gas guiding components, heat can be conducted when the composite phase change energy storage medium in the heating tank is heated using valley electricity. During steam generation, the fluctuation of the water flow agitates the composite phase change energy storage medium in the heating tank to prevent the formation of a temperature gradient layer. During this agitation, high-temperature inert gas is continuously guided into the interior of the molten composite phase change energy storage medium. While ensuring uniform heat distribution, the bubbles generated when the inert gas flows out of the molten composite phase change energy storage medium further bubble it, preventing the formation of a temperature gradient layer and effectively improving the thermal storage efficiency.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A valley electricity steam thermal energy storage device includes a heating tank and a storage tank. The heating tank contains a composite phase change energy storage medium and an inert gas. It also includes electrode rods, heat pipes, a floating assembly, a float, and a gas guiding assembly. The electrode rods are mounted on the heating tank and heat the composite phase change energy storage medium when valley electricity is applied. The heat pipes penetrate the storage tank, with their evaporation sections submerged in the composite phase change energy storage medium. Multiple sets of electrode rods and heat pipes are provided, with each set of heat pipes and electrode rods spaced apart. This spacing allows the evaporation sections of the heat pipes to effectively absorb the heat generated when the electrode rods are energized. The generated heat accelerates the heat transfer from the heating tank to the heat storage tank, thereby improving the heat storage efficiency. When the composite phase change energy storage medium is heated and melted, the heat pipe transfers heat from the evaporation section to the condensation section and heats the water in the heat storage tank. The floating component is installed through the heating tank and the heat storage tank. The float is installed on the floating component. When the water in the heat storage tank is heated and boils, the floating component drives the float to fluctuate up and down. The gas guiding component is installed on the float. When the float fluctuates up and down, the gas guiding component guides the inert gas in the heating tank to the molten composite phase change energy storage medium.

[0008] Preferably, the floating assembly includes a float plate, a first corrugated pipe, a first annular plate, a second corrugated pipe, a sleeve, and an L-shaped rod. The float plate is disposed in the heat storage tank, and the electrode rod is disposed at the bottom of the float plate with its lower end located inside the heating tank. The first corrugated pipe, the first annular plate, and the second corrugated pipe are all sleeved on the electrode rod. The two ends of the first corrugated pipe are respectively connected to the float plate and the heat storage tank. The first annular plate is disposed between the heating tank and the heat storage tank. The two ends of the second corrugated pipe are respectively connected to the heating tank and the first annular plate. The sleeve is disposed on the electrode rod through a groove. One end of the L-shaped rod is connected to the float block, and the other end is connected to the sleeve.

[0009] It is known that during the process of heating and storing energy using off-peak electricity, the energy storage material inside the heating tank gradually heats up and melts. However, the melting of the energy storage material proceeds gradually from the center of the heat source outwards. The melting energy storage material is blocked by unmelted energy storage material during diffusion, slowing down the heat diffusion rate and thus reducing the heat storage efficiency. To address this problem, this invention proposes a corresponding solution. Through the installation of electrode rods, heat pipes, and floats, after off-peak electricity is applied to the electrode rods, the composite phase change energy storage medium inside the heating tank can be heated. When the composite phase change energy storage medium melts, the evaporation section of the heat pipe absorbs heat and transfers it to the condensation section, thereby heating the water in the heat storage tank. During the heating process, the water in the heat storage tank will fluctuate. At this time, the float will fluctuate with the water flow, and the connection of the electrode rod will drive the float to fluctuate, thus stirring the molten composite phase change energy storage medium and increasing the diffusion rate of molecules in the molten composite phase change energy storage medium. This accelerates the heat diffusion rate inside the heat storage tank, effectively ensuring the heat storage efficiency.

[0010] Preferably, three electrode rods are provided, and grooves are formed on the surface of each electrode rod. These grooves are immersed in the composite phase change energy storage medium, and the groove height on the surface of the middle electrode rod is smaller than that on the surfaces of the two side electrode rods. By adopting the above scheme, the heating range can be expanded when using off-peak three-phase alternating current to heat the composite phase change energy storage medium in the heating tank, thereby accelerating the melting rate of the composite phase change energy storage medium and improving the heat storage efficiency.

[0011] Preferably, the gas guiding assembly includes a second annular plate, a sleeve, a gas pipe, a piston, a first one-way valve, and a second one-way valve. The float is hollow, the second annular plate is mounted on the middle electrode rod, the sleeve is mounted on the second annular plate, the piston is mounted on the gas pipe and sleeved with the sleeve, the lower end of the gas pipe extends into the interior of the float, the first one-way valve is mounted on the sleeve and positioned above the composite phase change energy storage medium, and the second one-way valve is positioned at the bottom of the float.

[0012] It is known that during the melting process of the composite phase change energy storage medium, heat flows upward and heats the inert gas in the heating tank, causing heat to accumulate inside the inert gas. This results in temperature differences at different heights of the composite phase change energy storage medium, which limits the heat storage efficiency. By utilizing the gas guiding components and the gap between the groove and the sleeve, the float is limited in its fluctuation amplitude by the composite phase change energy storage medium when it moves up and down on the float plate. This allows relative movement between the sleeve and the gas pipe, enabling the inert gas to be continuously guided into the float through one-way valves one and two. When the gas pressure inside the float exceeds the pressure exerted by the composite phase change energy storage medium on the outlet of one-way valve two, the inert gas is guided into the composite phase change energy storage medium. This not only guides heat and reduces the temperature difference at different heights within the composite phase change energy storage medium, but also increases the fluctuation amplitude in its molten state by utilizing the bubbles generated after the inert gas enters the composite phase change energy storage medium. This further disperses the temperature within the composite phase change energy storage medium, preventing the formation of a temperature gradient layer and further improving the thermal storage efficiency.

[0013] Preferably, the groove is a reciprocating thread groove, the float is cylindrical and has multiple flow-blocking grooves arranged in a circumferential array on its surface, the flow-blocking grooves are offset from the center line of the float along the center line of the horizontal plane, multiple floats are provided, and the flow-blocking grooves on the surfaces of two adjacent floats are offset in opposite directions from the center line of the horizontal plane.

[0014] By adopting the above scheme, the float will rotate during its up-and-down movement due to the obstruction of the molten composite phase change energy storage medium in the flow-blocking groove. During the rotation, the float can move up and down by utilizing the cooperation between the sleeve and the groove, allowing it to continuously move closer to and away from the lower end of the electrode rod. This increases the agitation amplitude of the molten composite phase change energy storage medium and promotes the relative movement between the sleeve and the gas pipe, ensuring the normal guidance of the inert gas and thus improving the thermal storage efficiency.

[0015] Preferably, the bottom of the heating tank is provided with a heat insulation cover, the bottom of the heat insulation cover is provided with a mounting plate, the mounting plate is provided on the heat storage tank, and the condensation section of the heat pipe is provided inside the heat insulation cover.

[0016] By adopting the above scheme, the heat from the condensing section of the heat pipe can be concentrated to heat the water accumulated inside the insulation cover in the heat storage tank. As the water inside the insulation cover is heated and flows upward, the amplitude of the water flow fluctuation is increased. This, in turn, increases the amplitude of the upward and downward fluctuation of the float plate under the fluctuation of the water flow in the heat storage tank. Furthermore, under the action of the electrode rod, the amplitude of the upward and downward fluctuation of the float is increased, further avoiding the formation of a temperature gradient layer in the heating tank, reducing heat loss, and improving the heat storage efficiency.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. Through the setting of electrode rods, heat pipes, floats, and floating components, when the electrode rods guide off-peak electricity to heat the composite phase change energy storage medium in the heating tank, the evaporation and condensation sections of the heat pipes can guide the heat to heat the water in the storage tank to generate steam for heat storage. During the process of the water in the storage tank heating up to generate steam, the fluctuation of the water flow will cause the float to stir in the molten composite phase change energy storage medium, thereby accelerating the rapid flow of the molten composite phase change energy storage medium. This ensures that the heat in the heating tank is evenly distributed and avoids the formation of a temperature gradient layer, thus effectively ensuring the electrothermal conversion efficiency and improving the overall heat storage efficiency.

[0019] 2. By using the floating components, gas guiding components, and grooves on the electrode rod, the contact range between the electrode rod and the composite phase change energy storage medium can be increased during the up-and-down movement of the floating plate. This expands the heating range of the composite phase change energy storage medium. Furthermore, by utilizing the resistance of the floating block, the sleeve moves back and forth along the axis of the electrode rod, allowing high-temperature inert gas to be continuously guided into the interior of the composite phase change energy storage medium. This promotes the uniform distribution of heat inside the heating tank, effectively avoids the formation of a temperature gradient layer, and improves the thermal storage efficiency.

[0020] 3. By using the flow-blocking grooves and gas-guiding components on the surface of the float, the resistance generated by the composite phase change energy storage medium when the float moves up and down will squeeze the flow-blocking grooves, causing the float to drive the sleeve to rotate through the L-shaped rod. This accelerates the relative movement between the float and the electrode rod under the action of the grooves, thereby speeding up the process of guiding the inert gas into the molten composite phase change energy storage medium. At the same time, the different directions of the flow-blocking grooves cause adjacent floats to rotate in opposite directions, further avoiding the formation of a temperature gradient layer in the heating tank and further improving the heat storage efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is a cross-sectional view of the connection structure of the heating tank, the heat storage tank, and the floating component of the present invention.

[0023] Figure 3 For the present invention Figure 2 Enlarged view of part A in the middle section;

[0024] Figure 4 This is a schematic diagram of the structure of some of the electrode rods and heat pipes of the present invention;

[0025] Figure 5 This is a schematic diagram of the connection structure between the float plate and the float block of the present invention;

[0026] Figure 6 This is a schematic diagram of the air guiding assembly of the present invention;

[0027] Figure 7 This is a schematic diagram showing the positional structure of the multiple floating blocks in this invention.

[0028] In the diagram: 1. Heating tank; 11. Insulation cover; 12. Mounting plate; 2. Heat storage tank; 3. Electrode rod; 31. Groove; 4. Heat pipe; 5. Floating assembly; 51. Float plate; 52. Bellows I; 53. Annular plate I; 54. Bellows II; 55. Sleeve; 56. L-shaped rod; 6. Float; 61. Flow-blocking groove; 7. Air guiding assembly; 71. Annular plate II; 72. Sleeve; 73. Air pipe; 74. Piston; 75. One-way valve I; 76. One-way valve II. Detailed Implementation

[0029] 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.

[0030] Please see Figures 1 to 7 This invention provides a valley electricity steam thermal energy storage device, the technical solution of which is as follows:

[0031] For details, please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4A valley electricity steam thermal energy storage device includes a heating tank 1 and a storage tank 2. The heating tank 1 contains a composite phase change energy storage medium and an inert gas, and also includes an electrode rod 3, a heat pipe 4, a floating component 5, a float 6, and a gas guiding component 7. The electrode rod 3 is mounted on the heating tank 1. When valley electricity is supplied to the electrode rod 3, it heats the composite phase change energy storage medium. The heat pipe 4 penetrates the storage tank 2, and its evaporation section is immersed in the composite phase change energy storage medium. A heat insulation cover 11 is provided at the bottom of the heating tank 1, and a mounting plate 12 is fixedly mounted at the bottom of the heat insulation cover 11. The mounting plate 12 can be fixed to the storage tank 2 by bolts to achieve a fixed connection between the heat insulation cover 11 and the heating tank 1. The condensation section of the heat pipe 4 is located inside the heat insulation cover 11. When heated by the electrode rod 3, the design of the heat pipe 4 causes the water in the storage tank 2 to boil, causing the floating component 5 to move irregularly up and down along the electrode rod 3 under the action of boiling water. Multiple sets of heat pipes 4 and electrode rods 3 are provided in each set, with each set of heat pipes 4 and electrode rods 3 arranged alternately. This alternating arrangement of heat pipes 4 and electrode rods 3 allows the evaporation section of heat pipes 4 to effectively absorb the heat generated when electrode rods 3 are energized, thereby accelerating the heat transfer from the heating tank to the heat storage tank 2 and improving the heat storage efficiency. There are three electrode rods 3, and grooves 31 are formed on the surface of the electrode rods 3. The grooves 31 on the surface of the middle electrode rod 3 are smaller than those on the two side electrode rods 3. Under the action of the grooves 31 on the surface of the electrode rod 3, the contact range between the composite phase change energy storage medium and the surface of the electrode rod 3 can be increased, so that the electrode rod 3 can increase the heating range of the composite phase change energy storage medium when energized, thereby improving the heat storage efficiency. When the composite phase change energy storage medium heats up and melts, the heat pipes 4 transfer heat from the evaporation section to the condensation section and heat the water in the heat storage tank 2, realizing the heat storage function of the heat storage tank 2.

[0032] As one embodiment of the present invention, refer to Figure 1 , Figure 2 and Figure 3A floating assembly 5 is installed through the heating tank 1 and the heat storage tank 2. A float 6 is installed on the floating assembly 5. When the water in the heat storage tank 2 is heated and boils, the floating assembly 5 drives the float 6 to fluctuate up and down. The floating assembly 5 includes a float plate 51, a first corrugated pipe 52, a first annular plate 53, a second corrugated pipe 54, a sleeve 55, and an L-shaped rod 56. The float plate 51 is installed in the heat storage tank 2. The electrode rod 3 is fixedly installed at the bottom of the float plate 51, with its lower end located inside the heating tank 1. The end of the electrode rod 3 installed in the heat storage tank 2 is waterproof and insulated to prevent leakage and safety accidents. The first corrugated pipe 52, the first annular plate 53, and the second corrugated pipe 54 are all... The corrugated pipe 52 is sleeved on the electrode rod 3. Its two ends are fixedly connected to the float plate 51 and the heat storage tank 2, respectively. The annular plate 53 is set between the heating tank 1 and the heat storage tank 2. The two ends of the corrugated pipe 54 are connected to the heating tank 1 and the annular plate 53, respectively. Both the corrugated pipe 52 and the corrugated pipe 54 are heat-insulating corrugated pipes, which not only achieves the sealing of the connection between the electrode rod 3 and the heating tank 1 and the heat storage tank 2, avoiding leakage of inert gas and water, but also reduces heat loss. The sleeve 55 is set on the electrode rod 3 through the groove 31. One end of the L-shaped rod 56 is connected to the float 6, and the other end is connected to the sleeve 55.

[0033] Under the above conditions, when a valley current is applied to electrode rod 3 to heat the composite phase change energy storage medium in heating tank 1, heat will be transferred inside the composite phase change energy storage medium, and the composite phase change energy storage material near electrode rod 3 will begin to melt first. After absorbing heat, the evaporation section of heat pipe 4 will transfer the heat from the evaporation section to the condensation section. The heat in the condensation section of heat pipe 4 will heat the water in heat storage tank 2, and the water in heat storage tank 2 will gradually heat up and vaporize, thus storing heat. During the heating process, the diffusion rate of water molecules in heat storage tank 2 will gradually increase. As the water flow causes fluctuations, the float 6, which floats in the water, will cause the float 6 to fluctuate. The up-and-down fluctuations of the float 6 will cause the electrode rod 3 to fluctuate. Since the electrode rod 3 is connected to the sleeve 55 through the groove 31, and the sleeve 55 is connected to the float 6 through the L-shaped rod 56, the float 6 will fluctuate along with the float plate 51 as the composite phase change energy storage medium gradually melts. This will agitate the composite phase change energy storage medium in the molten state, accelerate the diffusion rate of heat in the composite phase change energy storage medium, and thus improve the heat storage efficiency.

[0034] As one embodiment of the present invention, refer to Figure 1 , Figure 5 , Figure 6 and Figure 7The gas guiding component 7 is mounted on the float 6. When the float 6 moves up and down, the gas guiding component 7 guides the inert gas in the heating tank 1 into the molten composite phase change energy storage medium. The gas guiding component 7 includes an annular plate 71, a sleeve 72, a gas pipe 73, a piston 74, a one-way valve 75, and a two-way valve 76. The float 6 is hollow. The annular plate 71 is mounted on the middle electrode rod 3. The sleeve 72 is mounted on the annular plate 71. The piston 74 is mounted on the gas pipe 73 and is sleeved with the sleeve 72. The gas pipe 73... The lower end extends into the interior of the float 6. One-way valve 75 is mounted on the sleeve 72 and positioned above the composite phase change energy storage medium. One-way valve 76 is located at the bottom of the float 6. The groove 31 is a reciprocating threaded groove. This composite phase change energy storage medium is a chloride molten salt (NaCl-KCl-MgCl2 ternary eutectic salt can be used, which has a high latent heat of phase change, a mass ratio of 20:45:35, a melting point of 385℃, and a liquid phase density of 1.65 g / cm³ at an operating temperature of 450℃). 3 During the phase change process, it can absorb or release a large amount of latent heat, thereby effectively storing and releasing thermal energy. During the heating and melting process, an inert gas (which can be nitrogen with a purity of 99.9% and a pressure of 0.15 MPa at room temperature inside the heating tank 1) is used to isolate oxygen, which can prevent it from oxidizing and forming particles that would affect the movement and rotation of the sleeve 55 on the electrode rod 3. The float 6 is cylindrical and has multiple flow-blocking grooves 61 arranged in a circular array on its surface. The flow-blocking grooves 61 are offset from the center line of the float 6 along the center line of the horizontal plane. There are multiple floats 6, and the flow-blocking grooves 61 on the surface of two adjacent floats 6 are offset in opposite directions along the center line of the horizontal plane. It is also worth noting that all parts in contact with the composite phase change energy storage medium are made of 316L stainless steel to improve corrosion resistance.

[0035] Under the above-mentioned conditions, during the up-and-down fluctuation of the float 6, the flow-blocking groove 61 on its surface will be blocked by the composite phase change energy storage medium in the molten state, driving the float 6 to rotate. During the rotation of the float 6, the sleeve 55 will be driven to rotate through the connection of the L-shaped rod 56. Since the groove 31 is a reciprocating threaded groove, and the electrode rod 3 can only move vertically under the action of the float plate 51, the sleeve 55 will move up and down along the axis of the electrode rod 3 through the reciprocating threaded groove during the rotation, and will drive the float 6 to move vertically in sync under the action of the L-shaped rod 56. Since the sleeve 72 is connected to the electrode rod 3 through the annular plate 71, the sleeve 72 will rotate. Furthermore, the air pipe 73 is installed on the float 6. During the vertical reciprocating movement of the float 6, the air pipe 73 will drive the piston 74 installed on it to move synchronously inside the sleeve 72. Thus, under the one-way air guiding action of the one-way valve 1 75 and the one-way valve 2 76 (the opening pressure difference of the one-way valve 1 75 is 1.5 kPa, and the opening pressure difference of the one-way valve 2 76 is 2.0 kPa), the inert gas above the composite phase change energy storage medium can be guided into the interior of the composite phase change energy storage medium, which promotes the uniform distribution of heat inside the heat storage tank 2. In addition, during the up and down fluctuation of the electrode rod 3, the heating range can be expanded, the formation of the inclined temperature layer can be avoided, and the heat storage efficiency can be further improved.

[0036] Working principle:

[0037] When off-peak electricity is supplied to electrode rod 3, electrode rod 3 begins to heat the composite phase change energy storage medium in heating tank 1, causing the composite phase change energy storage medium to begin to heat up and melt. After the heat is transferred to the position of heat pipe 4, the evaporation section of heat pipe 4 absorbs the heat and transfers the heat to the condensation section. After the heat is transferred to the condensation section, it heats the water inside the insulation cover 11. During the heating process, the water molecules in the water inside the insulation cover 11 move faster after the temperature rises, causing the water in the heat storage tank 2 to fluctuate faster. During the fluctuation of the water, the floating float 51 will fluctuate, further accelerating the diffusion speed of water molecules, so that the heat of the water in the heat storage tank 2 can be quickly balanced, thereby improving the heat storage efficiency.

[0038] Since the float plate 51 is connected to the float block 6 set in the heating tank 1 in sequence through the electrode rod 3, the sleeve 55 and the L-shaped rod 56, the float plate 51 can drive the electrode rod 3 and the float block 6 to move up and down in the molten composite phase change energy storage medium during the up and down movement of the float plate 51 in the water. Among them, the electrode rod 3 can further expand the heating range by cooperating with the groove 31 on its own surface during the up and down movement of the float plate 51, while the float block 6 can increase the agitation of the molten composite phase change energy storage medium during the up and down movement of the float plate 51, accelerate the rapid diffusion of temperature in the molten composite phase change energy storage medium, avoid the formation of a temperature slope layer, and thus improve the heat storage efficiency.

[0039] During the up-and-down oscillation of the float 6, the flow-blocking grooves 61 on its surface are blocked by the composite phase change energy storage medium, causing the float 6 to rotate. Since the two ends of the L-shaped rod 56 are fixedly connected to the float 6 and the sleeve 55 respectively, and the groove 31 is a reciprocating thread groove, the sleeve 55 will reciprocate along the axis of the electrode rod 3 during rotation. When the sleeve 55 moves downward along the axis of the electrode rod 3, the sleeve 55 drives the float 6 away from the electrode rod 3 through the L-shaped rod 56. During this process, since the sleeve 55 can only rotate around the electrode rod 3 following the annular plate 71, the air pipe 73 installed on the float 6 moves away from the electrode rod 3. This will drive the piston 74 to move downwards. When the gas pipe 73 moves downwards, some of the inert gas in the heating tank 1 will be drawn into the sleeve 72 under the action of the one-way valve 75. When the sleeve 55 moves upwards along the axis of the electrode rod 3 during rotation, the float 6 will move closer to the electrode rod 3. During this process, the high-temperature inert gas stored in the sleeve 72 will be pressed into the interior of the composite phase change energy storage medium in the molten state under the action of the gas pipe 73 and the one-way valve 76. While achieving uniform mixing of heat inside the heating tank 1, the bubbles generated by the inert gas will expand the fluctuation range of the composite phase change energy storage medium, further avoiding the formation of a temperature slope layer and further improving the heat storage efficiency.

[0040] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A valley-electricity steam thermal energy storage device, comprising a heating tank (1) and a thermal storage tank (2), characterized in that: The heating tank (1) contains a composite phase change energy storage medium and an inert gas, and also includes an electrode rod (3), a heat pipe (4), a floating assembly (5), a float (6), and a gas guiding assembly (7). The electrode rod (3) is installed on the heating tank (1). When the electrode rod (3) is supplied with off-peak electricity, it heats the composite phase change energy storage medium. The heat pipe (4) is installed through the heat storage tank (2), and the evaporation section is immersed in the composite phase change energy storage medium. When the composite phase change energy storage medium heats up and melts, the heat pipe (4) transfers heat from the evaporation section to the condensation section. Water in the heat storage tank (2) is supplied and heated. The floating component (5) is installed through the heating tank (1) and the heat storage tank (2). The float (6) is installed on the floating component (5). When the water in the heat storage tank (2) is heated and boils, the floating component (5) drives the float (6) to fluctuate up and down. The gas guiding component (7) is installed on the float (6). When the float (6) fluctuates up and down, the gas guiding component (7) guides the inert gas in the heating tank (1) to the molten composite phase change energy storage medium.

2. The off-peak electricity steam thermal energy storage device according to claim 1, characterized in that: The floating assembly (5) includes a float plate (51), a first corrugated pipe (52), a first annular plate (53), a second corrugated pipe (54), a sleeve (55), and an L-shaped rod (56). The float plate (51) is disposed in the heat storage tank (2). The electrode rod (3) is disposed at the bottom of the float plate (51) and its lower end is located inside the heating tank (1). The first corrugated pipe (52), the first annular plate (53), and the second corrugated pipe (54) are all sleeved on the electrode rod (3). The two ends of the first corrugated pipe (52) are connected to the float plate (51) and the heat storage tank (2) respectively. The first annular plate (53) is set between the heating tank (1) and the heat storage tank (2). The two ends of the second corrugated pipe (54) are connected to the heating tank (1) and the first annular plate (53) respectively. The sleeve (55) is set on the electrode rod (3) through the groove (31). One end of the L-shaped rod (56) is connected to the float (6), and the other end is connected to the sleeve (55).

3. The off-peak electricity steam thermal energy storage device according to claim 1, characterized in that: The electrode rod (3) and heat pipe (4) are provided in multiple sets, and the heat pipe (4) and electrode rod (3) in each set are arranged alternately.

4. The off-peak electricity steam thermal energy storage device according to claim 2, characterized in that: The electrode rod (3) is provided with three rods. The surface of the electrode rod (3) is provided with grooves (31). The grooves (31) are immersed in the composite phase change energy storage medium. The height of the groove (31) on the surface of the middle electrode rod (3) is less than the height of the grooves (31) on the surface of the two side electrode rods (3).

5. The off-peak electricity steam thermal energy storage device according to claim 1, characterized in that: The gas guiding assembly (7) includes an annular plate two (71), a sleeve (72), a gas pipe (73), a piston (74), a one-way valve one (75), and a one-way valve two (76). The float (6) is hollow. The annular plate two (71) is set on the middle electrode rod (3). The sleeve (72) is set on the annular plate two (71). The piston (74) is set on the gas pipe (73) and sleeved with the sleeve (72). The lower end of the gas pipe (73) extends into the interior of the float (6). The one-way valve one (75) is set on the sleeve (72) and above the composite phase change energy storage medium. The one-way valve two (76) is set at the bottom of the float (6).

6. The off-peak electricity steam thermal energy storage device according to claim 1, characterized in that: The groove (31) is a reciprocating thread groove, the float (6) is cylindrical and has multiple flow-blocking grooves (61) arranged in a circular array on its surface, and the flow-blocking grooves (61) are offset from the center line of the float (6) along the center line of the horizontal plane.

7. The off-peak electricity steam thermal energy storage device according to claim 6, characterized in that: The float (6) is provided in multiple ways, and the flow-blocking grooves (61) on the surfaces of two adjacent floats (6) deviate in opposite directions along the center line of the horizontal plane.

8. The off-peak electricity steam thermal energy storage device according to claim 1, characterized in that: The bottom of the heating tank (1) is provided with a heat insulation cover (11), and the bottom of the heat insulation cover (11) is provided with a mounting plate (12). The mounting plate (12) is provided on the heat storage tank (2), and the condensation section of the heat pipe (4) is provided inside the heat insulation cover (11).

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