Non-full charge phase change capsule liquid-solid fluidized bed heat storage device

Abstract

The application provides a non-full filling phase change capsule liquid-solid fluidized bed heat storage device, and belongs to the technical field of heat storage. In view of the problem of insufficient heat transfer efficiency of the existing phase change heat storage equipment, the following technical scheme is provided. The fluidized bed main body of the device is a cylindrical barrel, and a conical pipeline is arranged at the upper and lower ends to realize uniform flow distribution, and a ball blocking net is arranged to block the capsules and allow only the medium fluid to pass. The barrel is covered with a heat preservation layer to reduce heat loss. The core heat storage carrier of the device is a core-shell structure phase change capsule with internal non-full filling phase change material. According to the density difference between the capsule and the external medium, the capsule forms a liquid-solid fluidized state of suspension, rotation and collision through the combined action of downward liquid flow and buoyancy, or the fluid pumped from the bottom to overcome gravity. A flow valve is arranged to adjust the flow to ensure stable fluidization. The fluidized state significantly weakens the temperature stratification phenomenon of the fluidized medium, and at the same time promotes the forced convection of the phase change material in the capsule, destroys the thermal boundary layer and strengthens the heat transfer, and effectively improves the heat storage and release efficiency.

Description

Background Technology

[0001] Currently, the most widely used thermal storage technologies in the industrial sector include sensible thermal storage technology and phase change thermal storage technology.

[0002] Sensible heat storage technologies (such as hot water storage tanks and thermal oil storage) hold an important position in the current market due to their mature technology and simple structure. However, sensible heat storage relies solely on the temperature rise of the medium to store energy, resulting in low heat storage density and large storage devices requiring significant floor space. Furthermore, during heat release, the output temperature of sensible heat storage continuously decreases as the temperature of the storage medium drops, making it difficult to meet the needs of applications requiring constant temperature heating, and significant heat loss occurs during long-term heat preservation.

[0003] To overcome the low energy density of sensible thermal energy storage, fixed-bed (filled-bed) phase change thermal energy storage technology has been extensively studied. This technology encapsulates phase change materials (PCAs) within spherical or tubular shells and statically stacks them, utilizing the absorption or release of latent heat during the phase change process of the PCAs to achieve high-energy-density isothermal thermal energy storage. However, fixed-bed structures have revealed significant performance bottlenecks in practical engineering applications. First, due to the extremely low thermal conductivity of most PCAs, during the thermal storage and release cycle, as the phase change interface advances, the material layer that has undergone phase change forms an ever-thickening thermal boundary layer, causing the system's heat exchange power to decrease exponentially with operating time. Second, the statically stacked capsules result in complex and highly non-uniform fluid channels within the bed, significantly increasing the system's pumping resistance and easily triggering severe "channeling" and temperature stratification, preventing some thermal storage materials from effectively participating in heat exchange and reducing the overall system utilization rate. Furthermore, PCAs often undergo significant volume expansion or contraction during solid-liquid phase changes, leading to fatigue damage of the encapsulation shell and leakage of the PCAs.

[0004] Although some studies have attempted to enhance heat transfer by adding fins or thermally conductive skeletons inside the fixed bed, this increases the system's weight and cost, and has not fundamentally solved the problems of uneven flow field and power attenuation.

[0005] Therefore, how to completely break through the thermal boundary layer barrier in the phase change process, eliminate the flow field deterioration and temperature stratification phenomenon inside the bed, and at the same time ensure the fluidization stability of the phase change capsule during long-term operation is a technical problem that urgently needs to be solved in the field of thermal energy storage. Summary of the Invention

[0006] The purpose of this invention is to provide a non-fully filled phase change capsule liquid-solid fluidized bed thermal energy storage device to solve the problems of low phase change heat transfer rate, uneven flow field distribution and easy damage of capsules due to volume expansion in existing thermal energy storage equipment, so as to achieve efficient, stable and long-life thermal energy storage and release.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a non-fully filled phase change capsule liquid-solid fluidized bed thermal storage device, comprising a fluidized bed body, an external insulation layer, a phase change capsule filled inside, a fluidized heat exchange medium, and a pipeline and instrumentation system for controlling the fluid and monitoring the status.

[0008] The fluidized bed body includes a cylindrical fluidized bed shell in the middle. The top and bottom of the fluidized bed shell are respectively connected to tapered pipes that gradually narrow and expand, which are used to achieve uniform distribution of the fluidized heat exchange medium when it enters or flows out of the shell. The top and bottom of the fluidized bed shell are respectively provided with baffle plates. The phase change capsule is confined in the space between the upper and lower baffle plates. The aperture of the baffle plates is smaller than the particle size of the phase change capsule, allowing only the fluidized heat exchange medium to pass through.

[0009] The phase change capsule is a non-fully filled core-shell structure, comprising a phase change capsule shell, a phase change material encapsulated inside the shell, and a pre-reserved gas cavity inside the shell. The gas cavity provides a buffer space for the volume expansion of the phase change material during the solid-liquid phase change process, and simultaneously stimulates forced convection inside the phase change material during fluidization.

[0010] The piping and instrumentation system includes a flow regulating valve located at one end of the fluidized bed body, and fluidized heat exchange medium inlet and fluidized heat exchanger unit outlet located at both ends of the pipeline. In addition, the system is equipped with thermometers and pressure gauges. The thermometers are located at the fluid inlet and outlet ends to monitor the temperature before and after heat exchange; the pressure gauges are located at the top and bottom of the fluidized bed shell to monitor the bed pressure drop in real time to determine the fluidization state.

[0011] Optionally, the static filling volume of the phase change capsules inside the fluidized bed body accounts for 30%-60% of the total internal volume of the cylindrical shell.

[0012] Optionally, the tapered pipe has an expansion or contraction angle of 30-80°, and its axial length is 0.2-0.5 times the inner diameter of the cylindrical tube.

[0013] Optionally, the length-to-diameter ratio (i.e., the ratio of length to inner diameter) of the cylindrical body in the fluidized bed is 2-5.

[0014] Optionally, the outer diameter of the phase change capsule is 5-20 mm, preferably 10 mm. The phase change material filling rate inside the phase change capsule is 50-90%, preferably 75%.

[0015] Optionally, the outer shell of the phase change capsule may be made of polymer material, metal material or inorganic non-metallic material, and the phase change material filled inside the phase change capsule may be organic phase change material or inorganic phase change material.

[0016] Optionally, the fluidized bed body and conical pipe can be made of stainless steel, carbon steel or high-temperature resistant alloy materials.

[0017] Optionally, the fluidized heat exchange medium can be water, heat transfer oil, alcohol solution or liquid molten salt.

[0018] The synergistic effect of fluidized bed liquid-solid fluidization and phase change in this invention has the following beneficial effects: Taking the case where the density of the capsule is less than that of the fluid medium as an example: During operation, the fluid medium flows from top to bottom, and the capsule, under the combined action of fluid dynamics and its own buoyancy, breaks away from the fixed accumulation state and enters a suspended motion state, forming a stable liquid-solid fluidization state.

[0019] Under stable fluidization conditions, phase change capsules exhibit distinct random motion characteristics within the bed, including floating, sinking, rotation, and lateral migration, while frequent collisions and interactions occur between capsules. This multi-scale, multi-directional interaction keeps the capsules in a state of continuous disturbance, resulting in a strong macroscopic mixing effect. Compared to traditional fixed beds, fluidization significantly reduces temperature stratification in the fluidized medium, leading to a more uniform temperature distribution within the bed and thus improving overall heat transfer performance.

[0020] The collisions and shearing between capsules induce forced motion in the internal phase change material. The partially filled structure of the phase change capsules contains a certain amount of free space. When the outer capsules collide or accelerate, the internal liquid phase change material experiences relative flow, forming an internal circulating flow similar to "shaking." This forced motion effectively disrupts the thermal boundary layer formed under traditional conduction-dominated conditions, transforming the heat transfer mechanism from a single conduction process to a coupled process of conduction and forced convection, significantly improving the heat transfer rate of the phase change material.

[0021] Furthermore, based on the density difference between the overall density of the phase change capsule and the density of the fluidized heat transfer medium, the fluidization operation mechanism of the present invention includes the following two modes: Mode 1 (Downward Fluidization): When using phase change capsules with an overall density less than that of the fluidizing heat transfer medium, the fluidizing heat transfer medium is pumped in through a flow regulating valve from the top fluidizing heat transfer medium inlet and flows downward through the cylindrical fluidized bed shell. Through the combined action of the downward liquid flow drag force and the buoyancy of the phase change capsule itself, a dynamic equilibrium is achieved, causing the phase change capsule to form a fluidized state of suspension, rotation, and collision within the bed (e.g., ...). Figure 1 (as shown) Mode 2 (Upward Fluidization): When using a phase change capsule with an overall density greater than that of the fluidizing heat transfer medium, the fluidizing heat transfer medium is pumped in through a conical pipe at the bottom and flows upward through the cylindrical fluidized bed shell. The strong upward flow of liquid from the bottom overcomes the phase change capsule's own gravity, causing it to form a liquid-solid fluidization state of suspension, rotation, and collision.

[0022] Furthermore, the upper and lower ends of the fluidized bed shell are connected to tapered pipes that gradually narrow or widen. By smoothly converting the dynamic and static pressure of the fluid, a uniform velocity field is formed on the cross-section of the cylinder, eliminating local dead zones and channeling phenomena, and achieving uniform flow distribution.

[0023] Furthermore, the fluidized bed shell is symmetrically equipped with porous baffles at the top and bottom, with apertures smaller than the minimum characteristic size of the capsule. This allows the heat exchange medium to pass through with low resistance while reliably intercepting the capsule, effectively preventing capsule loss or pipeline blockage.

[0024] Furthermore, the phase change capsule adopts a non-full-fill structure with different filling rates, and can flexibly adapt to different fluidizing media by precisely controlling the overall density. It also utilizes the swaying of the internal air cavity in fluidization to stimulate forced convection, which significantly enhances the heat transfer efficiency.

[0025] Furthermore, phase change capsules encompass ellipsoidal, polyhedral, or irregularly shaped structures with surface textures, utilizing differentiated drag coefficients to induce more intense rotation and collisions, thereby completely disrupting the thermal boundary layer and improving the overall heat transfer coefficient.

[0026] Furthermore, the system adopts a closed-loop control strategy based on real-time monitoring of bed pressure difference, and adaptively corrects flow anomalies by dynamically adjusting the flow valve to ensure that the capsule is always maintained in a highly efficient and stable fluidization state. Attached Figure Description

[0027] Figure 1 This is a front view of the non-fully filled phase change capsule liquid-solid fluidized bed of the present invention, showing the overall structure of the fluidized bed.

[0028] Figure 2 This is a cross-sectional view of the fluidized bed (AA), showing the fluidized bed configuration.

[0029] Figure 3 This is a cross-sectional view of a phase change capsule, showing the filling of the phase change material.

[0030] Figure 1 : 1. Flow regulating valve; 2. Fluidized heat exchange medium inlet; 3. Conical pipe; 4. Baffle plate; 5. Fluidized bed shell; 6. Insulation layer; 7. Phase change capsule; 8. Fluidized heat exchange medium; 9. Baffle plate; 10. Fluidized heat exchange medium outlet; 11. Thermometer; 12. Pressure gauge; 13. Pressure gauge; 14. Thermometer. Figure 2 : 5. Fluidized bed shell, 6. Insulation layer, 7. Phase change capsule, 8. Fluidized heat exchange medium Figure 3 : 1. Gas cavity, 2. Phase change material, 3. Phase change capsule shell Specific implementation methods

[0031] The following is a detailed description of embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements with similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships, are based on the accompanying drawings, in particular... Figure 1 The orientation or positional relationship shown when the fluidized bed is placed vertically is only for the purpose of describing the present invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation (for example, although the core cylinder of this device is mainly vertical, it does not exclude the inclined arrangement under specific working conditions), and therefore should not be construed as a limitation of the present invention.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, such as a plurality of phase change capsules packed within a bed, unless otherwise explicitly specified. Unless otherwise defined, all technical and scientific terms used herein, such as "fluidization," "boundary layer," "pressure drop," etc., have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0034] The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections (such as welding a tapered pipe to a cylindrical shell), detachable connections (such as threaded or flanged connections of thermometers or pressure gauges), or integral connections; they can refer to mechanical connections or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium (such as contact heat transfer between a fluidized heat exchange medium and a phase change capsule shell); they can refer to the internal communication between two components (such as the internal communication between a fluid pipeline and the fluidized bed body) or the interaction between two components. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Those skilled in the art will understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. In this invention, unless expressly specified and limited otherwise, "above" or "below" a second feature can include direct contact between the first and second features, or contact between the first and second features not in direct contact but through another feature between them, such as a phase change capsule located below an upper baffle plate and above a lower baffle plate, but not always in direct contact. Furthermore, "above," "over," and "on top" of a second feature include the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" of a second feature include the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0036] The following disclosure provides different embodiments or examples, such as a downward flow pattern for light capsules and an upward flow pattern for heavy capsules, to achieve different structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the invention. Furthermore, reference numerals (such as reference numerals 1-14) and reference letters may be repeated in different examples; this repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and arrangements discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and the use of other materials.

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0038] Example 1: The overall system structure and connection relationships are as follows Figure 1 and Figure 2 As shown, a non-fully filled phase change capsule liquid-solid fluidized bed thermal storage device mainly consists of three parts: a fluidized bed body, an internal thermal storage carrier, and external control pipelines. The fluidized bed body includes a cylindrical fluidized bed shell 5 in the middle. To reduce heat loss during the heat storage and release process and ensure thermal storage stability, the fluidized bed shell 5 is entirely covered with an insulation layer 6, such as rock wool or polyurethane insulation material. The length-to-diameter ratio (i.e., the ratio of length to inner diameter) of the cylindrical body in the fluidized bed body is preferably 2-5.

[0039] The top and bottom of the fluidized bed shell 5 are respectively connected to tapered pipes 3 that taper / expansion. The taper angle of the tapered pipe 3 is preferably 30-80°, and its axial length is 0.2-0.5 times the inner diameter of the cylindrical shell. This structure is used to achieve a smooth transition of the fluidized heat exchange medium 8 when entering or exiting the cylindrical shell, thereby forming a uniform velocity field on the cross-section of the shell, achieving uniform flow distribution, and eliminating local dead zones and channeling phenomena.

[0040] Inside the fluidized bed shell 5, baffle plates are horizontally arranged at the top and bottom, namely the upper baffle plate 4 and the lower baffle plate 9. The area between the two baffle plates constitutes the fluidization zone of the phase change capsule 7. The baffle plates have a porous structure, and their flow aperture is strictly smaller than the minimum particle size of the phase change capsule 7. This allows the fluidized heat exchange medium 8 to pass through with low resistance while effectively intercepting the phase change capsule 7, preventing it from leaking or causing blockage of external pipelines.

[0041] The external piping and instrumentation system includes a flow regulating valve 1 installed at the medium inlet for precise flow rate control. A fluidized heat exchange medium inlet 2 is located at the top of the system, and a fluidized heat exchanger unit outlet 10 is located at the bottom (in downward fluidization mode). Furthermore, thermometers 11 and 14 are installed at the fluid inlet and outlet respectively to monitor the temperature changes of the medium before and after heat exchange in real time. Pressure gauges 12 and 13 are installed near the baffle plates 4 and 9 on the fluidized bed shell 5 to read the pressure difference between the upper and lower layers of the bed in real time.

[0042] Example 2: Structural features of phase change capsules as follows Figure 3 As shown, the core heat storage carrier in this embodiment is a phase change capsule 7 with a non-fully filled structure. Specifically, it includes an outermost phase change capsule shell 3, an internally encapsulated phase change material 2, and a reserved air cavity 1. The outer diameter of the phase change capsule 7 is set between 5-20 mm, preferably 10 mm. In a static state, the phase change capsule 7 fills 30%-60% of the total volume inside the cylindrical body. The non-fully filled design has a dual function: on the one hand, the air cavity 1 provides sufficient buffer space for the volume expansion of the phase change material 2 during the solid-liquid phase change process, preventing the phase change capsule shell 3 from cracking due to stress concentration; on the other hand, during capsule fluidization and tumbling, the violent shaking of the air cavity 1 can effectively stimulate forced convection inside the phase change material 2.

[0043] Example 3: Downward fluidization operation mode. For light capsules, when the overall density of the phase change capsule 7 is less than the density of the fluidizing heat exchange medium 8 (such as water or salt solution), the system operates in downward fluidization mode. The specific operation process is as follows: The fluidizing heat exchange medium 8 is pumped in from the top fluidizing heat exchange medium inlet 2, flows through the flow regulating valve 1, is evenly distributed through the top conical pipe 3, and passes through the baffle plate 4 into the fluidized bed shell 5. The fluidizing heat exchange medium 8 flows from top to bottom, generating a downward drag force on the statically stacked phase change capsule 7. When the downward liquid drag force and the upward buoyancy of the phase change capsule 7 itself reach dynamic equilibrium, the capsule detaches from the fixed stacking state of the upper layer and enters a liquid-solid fluidization state of suspension, rotation, and collision. In this state, the capsule frequently collides and migrates laterally, causing the internal phase change material 2 to be forced to shake, transforming the single heat conduction process into a coupled process of heat conduction and forced convection, completely destroying the heat conduction boundary layer. After heat exchange, the medium passes through the lower baffle plate 9 and flows out from the outlet 10 of the fluidized heat exchanger unit into the next cycle.

[0044] Example 4: Upward Fluidization Operation Mode. For heavy capsules, when the overall density of the phase change capsule 7 is greater than the density of the fluidized heat exchange medium 8, the system operates in upward fluidization mode. The specific operation process is as follows: The external pipeline connection is changed so that the fluidized heat exchange medium 8 is pumped in reverse from the bottom outlet 10, and enters the cylinder from bottom to top through the lower conical pipe and baffle 9. The strong upward liquid flow drag force overcomes the gravity of the phase change capsule 7, causing it to detach from the static accumulation at the bottom and form a suspended, rotating fluidized state. This mode can also reduce medium temperature stratification and achieve efficient phase change heat storage and release.

[0045] Example 5: Closed-Loop Stabilization Control Based on Differential Pressure Monitoring During the aforementioned heat storage and release operation, the system introduces a closed-loop control strategy to maintain a stable fluidization state. The pressure drop of the current bed is calculated by real-time acquisition of readings from pressure gauges 12 and 13. The control system compares the real-time pressure drop with a preset stable fluidization pressure drop range: when the pressure drop drops abnormally and sharply, it is determined that the fluid has experienced "channeling" or flow instability, and the system sends a feedback signal to flow regulating valve 1 to appropriately increase the flow rate to re-guide the flow and disperse the capsules; when the pressure drop rises abnormally, it is determined to be a local blockage, and the system controls flow regulating valve 1 to appropriately reduce the flow rate. Through this adaptive correction mechanism, it is ensured that the phase change capsule 7 is always maintained in an ideal fluidization state with controllable collision wear and optimal heat transfer efficiency.

[0046] This invention has the following significant advantages, which directly address and partially solve problems in existing thermal storage devices such as low thermal storage density, low phase change heat transfer rate, uneven flow field distribution, and susceptibility of capsules to volume expansion damage. Breaking through the thermal conductivity bottleneck and greatly improving the heat transfer rate: This invention innovatively couples a non-fully filled phase change capsule with a liquid-solid fluidization state. The intense external disturbances generated during the fluidization process of suspension and collision of the capsule are transformed into forced convection of the internal phase change material, completely destroying the traditional thermal resistance boundary layer. This mechanism upgrades the heat transfer mode from single thermal conduction to a synergistic heat exchange of "conduction + convection", achieving a qualitative leap in the storage and release of heat power.

[0047] Reshaping the flow uniformity structure and completely eliminating flow field deterioration: The use of tapered pipes with gradually expanding / contracting ends achieves a smooth transition between the dynamic and static pressures of the fluid. This structure creates a highly uniform velocity field across the fluidized bed cross-section, effectively eliminating the "channeling," "dead zones," and severe temperature stratification phenomena commonly found in traditional thermal storage beds, while significantly reducing the system's pumping pressure drop.

[0048] Constructing a buffer space significantly extends capsule life: Addressing the volume expansion characteristics of phase change materials during solid-liquid conversion, the pre-reserved air cavity inside the capsule provides ample physical buffer space. This non-fully-filled design effectively releases localized stress concentration caused by volume expansion, fundamentally reducing the risk of capsule rupture and leakage during long-term high-frequency charge-discharge cycles.

[0049] Integrated intelligent control ensures long-term system stability: Leveraging the high thermal density of phase change materials, this device further introduces a closed-loop control strategy based on real-time monitoring of the pressure difference between the upper and lower layers of the bed. The system can predict flow anomalies (such as blockage or instability) in advance and adaptively adjust the inlet flow rate, ensuring that the thermal storage medium is always maintained in an optimal fluidization state with high efficiency and low wear, greatly improving the engineering applicability and operational reliability of the device.

[0050] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In the above embodiments of this application, the descriptions of each embodiment have their own emphasis. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments. For example, the specific logic of voltage drop monitoring in Mode 1 and Mode 2 can be used as mutual reference.

[0051] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of units, such as the fluidized bed body, piping system, and monitoring instruments, can be a logical functional division. In actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections, such as the feedback connection between pressure signals and flow control valves, can be indirect couplings or communication connections through interfaces, units, or modules, and can be electrical, mechanical, or other forms.

[0052] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0053] The above description is merely a preferred embodiment of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application (such as replacing different phase change materials for specific temperature zones, adjusting the specific scaling ratio of the conical pipe, etc.). These improvements and modifications should also be considered within the scope of protection of this application. It should be understood that the above description is for illustrative purposes only and not for limitation. Many embodiments and applications beyond the provided examples, such as industrial waste heat recovery, building heating, or cold chain logistics energy storage, will become apparent to those skilled in the art upon reading the above description.

[0054] Therefore, the scope of this patent should not be determined by reference to the foregoing description, but rather by reference to the foregoing claims and the full scope of their equivalents. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not an abandonment of that subject matter, nor should it be considered that the applicant has not considered it part of the disclosed inventive subject matter.

Claims

1. A phase change capsule liquid-solid fluidized bed thermal storage device, characterized in that, It includes a fluidized bed body, an external insulation layer, a phase change capsule filled inside, a fluidized heat exchange medium, and piping and instrumentation systems for controlling the fluid and monitoring its status; The fluidized bed body includes a cylindrical fluidized bed shell in the middle. The top and bottom of the fluidized bed shell are respectively connected to tapered pipes that gradually narrow or expand, which are used to achieve uniform distribution of the fluidized heat exchange medium when it enters or flows out of the shell. The top and bottom of the fluidized bed shell are respectively provided with baffles. The phase change capsule is confined in the space between the upper and lower baffles. The aperture of the baffles is smaller than the particle size of the phase change capsule, allowing only the fluidized heat exchange medium to pass through. The phase change capsule is a non-fully filled core-shell structure, which includes a phase change capsule shell, a phase change material encapsulated inside the shell, and a gas cavity reserved inside the shell. The piping and instrumentation system includes a flow regulating valve located at one end of the fluidized bed body, and fluidized heat exchange medium inlet and fluidized heat exchange unit outlet located at both ends of the pipeline; the system is equipped with a thermometer and a pressure gauge, wherein the thermometer is located at the fluid inlet and outlet, and the pressure gauge is located at the top and bottom of the fluidized bed shell.

2. The phase change capsule liquid-solid fluidized bed thermal storage device according to claim 1, characterized in that, When a phase change capsule with an overall density less than that of the fluidized heat exchange medium is used, the fluidized heat exchange medium is pumped in through the flow regulating valve at the top fluidized heat exchange medium inlet and flows from top to bottom through the cylindrical fluidized bed shell; through the combined action of the downward liquid flow drag force and the buoyancy of the phase change capsule itself, the phase change capsule forms a fluidized state of suspension, rotation and collision in the bed.

3. The phase change capsule liquid-solid fluidized bed thermal storage device according to claim 1, characterized in that, When a phase change capsule with an overall density greater than that of the fluidized heat exchange medium is used, the fluidized heat exchange medium is pumped in through a conical pipe at the bottom and flows upward through the cylindrical fluidized bed shell. The strong upward flow of liquid from the bottom overcomes the gravity of the phase change capsule itself, causing it to form a liquid-solid fluidization state of suspension, rotation, and collision.

4. The phase change capsule liquid-solid fluidized bed thermal storage device according to claim 1, characterized in that, The system adopts a closed-loop control strategy based on real-time monitoring of bed pressure difference; it calculates the current pressure drop of the bed by collecting the readings of the pressure gauges at the top and bottom of the fluidized bed shell in real time; the control system compares the real-time pressure drop with the preset stable fluidization pressure drop range, and adaptively corrects abnormal flow conditions by dynamically adjusting the flow regulating valve to ensure that the capsule maintains a stable fluidization state.

5. The phase change capsule liquid-solid fluidized bed thermal storage device according to claim 1, characterized in that, The static filling volume of phase change capsules inside the fluidized bed body accounts for 30%-90% of the total internal volume of the cylindrical shell.

6. The phase change capsule liquid-solid fluidized bed thermal storage device according to claim 1, characterized in that, The conical pipe has an expansion or contraction angle of 30-80°, and its axial length is 0.2-0.5 times the inner diameter of the cylindrical tube; the ratio of the length to the inner diameter of the cylindrical tube in the fluidized bed body is 2-5.

7. The phase change capsule liquid-solid fluidized bed thermal storage device according to claim 1, characterized in that, The outer diameter of the phase change capsule is 5-20mm, and the phase change material filling rate inside the phase change capsule is 50-90%.

8. The phase change capsule liquid-solid fluidized bed thermal storage device according to claim 1, characterized in that, Phase change capsules encompass ellipsoidal, polyhedral, or irregularly shaped structures with surface textures.

9. The phase change capsule liquid-solid fluidized bed thermal storage device according to claim 1, characterized in that, The outer shell of the phase change capsule is made of polymer, metal or inorganic non-metal; the phase change material filled inside the phase change capsule is organic or inorganic; the fluidized bed body and conical pipe are made of stainless steel, carbon steel or high-temperature alloy; the fluidized heat exchange medium is water, heat transfer oil, alcohol solution or liquid molten salt.

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