A detachable heat storage and exchange device based on high-temperature-resistant phase change microcapsule particles and an application method thereof

Abstract

The application discloses a detachable heat storage and exchange device based on high-temperature-resistant phase change microcapsule particles and an application method thereof.The device comprises a high-temperature-resistant outer shell, a microporous sieve plate, a high-temperature phase change microcapsule filling layer, a flow guide structure and a quick connection interface.The shell is filled with phase change microcapsule particles of high-temperature phase change materials packaged by high-temperature-resistant inorganic shells, forming a porous medium filling bed.When a high-temperature fluid to be cooled flows through the gap between the particles, the microcapsules absorb heat through phase change, quickly reduce the temperature of the fluid and store heat in the form of latent heat at high density.When the heat storage is saturated, the whole device or the internal module can be taken out, as an independent "heat battery", which is placed in a low-temperature fluid to heat the low-temperature fluid through the reverse solidification heat release process of the phase change material.The application realizes rapid transfer, high-density storage and flexible utilization of heat energy, and is particularly suitable for intermittent high-temperature waste heat recovery, emergency cooling and mobile heating scenes.

Description

Technical Field

[0001] This invention relates to the field of thermal energy storage and utilization technology, specifically to a thermal energy storage and heat exchange device based on phase change materials, and more particularly to a device and method that uses high-temperature resistant phase change microcapsule particles as the thermal energy storage medium to achieve rapid heat exchange, modular access, and flexible heating. Background Technology

[0002] Industrial production and energy systems often generate large amounts of medium- and low-temperature waste heat, such as engine exhaust, industrial furnace exhaust, and process cooling water. This heat is of low quality, and direct discharge results in energy waste and thermal pollution. Meanwhile, in certain situations (such as field operations and emergency response), rapid cooling of high-temperature fluids or provision of a stable heat source for low-temperature objects is required.

[0003] Traditional thermal storage technologies are mainly divided into sensible thermal storage and latent thermal storage. Sensible thermal storage (such as refractory bricks and water tanks) has low thermal density and requires large device volume. Latent thermal storage utilizes the latent heat of phase change materials (PCMs), resulting in a much higher thermal density than sensible thermal storage. However, traditional block or macroscopically packaged PCMs suffer from problems such as low thermal conductivity, large volume changes during phase change, limited contact area with heat exchange fluids, potential corrosion of containers, and solid-liquid phase separation, leading to slow charging / discharging rates and poor cycle stability.

[0004] Phase change microencapsulation (PCM) technology encapsulates PCM within micron- or millimeter-sized shells, effectively addressing issues of leakage, corrosion, and volume changes. Its small particle size and large specific surface area significantly enhance heat transfer. However, most commercially available PCM microcapsules currently use organic polymer shells (such as melamine resin), whose temperature resistance is typically below 200°C. Prolonged exposure to high temperatures can lead to aging and decomposition, making them unsuitable for medium- to high-temperature industrial waste heat recovery scenarios. Furthermore, existing PCM-based heat storage devices are mostly stationary, with heat storage and release occurring in the same location, hindering flexible spatial transfer of thermal energy. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide a detachable heat storage and exchange device based on high-temperature resistant phase change microcapsule particles and its application method. This device can not only efficiently and rapidly absorb and store heat from high-temperature fluids at high density, but also function as a portable thermal battery, releasing the stored heat at another location and time to heat low-temperature objects, thus achieving heat energy transfer.

[0006] The core concept of this invention is to utilize high-temperature phase change microcapsule particles encapsulated in high-temperature resistant inorganic materials as a heat storage medium to construct a compact packed bed heat exchange unit. During the heat storage stage, a high-temperature fluid is forced through the packed bed, and the high-temperature microcapsule particles rapidly absorb heat and undergo phase change due to their large specific surface area. After heat storage saturation, the entire heat storage unit can be quickly disassembled and transferred to the location where heat is needed. The stored latent heat is released through different heat exchange methods (such as countercurrent heat exchange with a low-temperature fluid or direct contact heating), realizing the movement and reuse of thermal energy.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A detachable heat storage and exchange device based on high-temperature phase change microcapsule particles includes a sealed shell and high-temperature phase change microcapsule particles filled therein. The outer shell of the high-temperature phase change microcapsule particles is made of inorganic materials, such as silicon dioxide and alumina, to ensure structural stability under long-term high temperatures. The internal phase change material (PCM) core material is selected from metal alloys, molten salts, etc., with a phase change temperature higher than 100℃. The particle stacking forms a packed bed with high porosity, providing a large surface area for fluid flow and heat exchange.

[0008] A detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles, comprising: The high-temperature resistant outer shell serves as the pressure-bearing and sealed container for the entire device. Its basic shape is cylindrical or cuboid to facilitate manufacturing and stacking. The outer shell has fluid inlets and outlets, typically located at the central axis at both ends to ensure uniform fluid flow across the entire filler cross-section. The outer shell has porous support structures at both ends. These structures are preferably microporous metal sieve plates or sintered ceramic porous plates. Their core functions are twofold: first, to support the internally packed high-temperature phase-change microcapsule particle layer, preventing it from clogging the flow channels or becoming damaged due to fluid impact or its own weight; second, to act as a filtration barrier. The micropore diameter is designed to be smaller than the minimum particle size of the packed microcapsules (e.g., if the minimum particle size is 50 μm, the sieve plate pore diameter can be 30 μm), thereby effectively preventing particles from being lost with the fluid. These two porous support structures, together with the inner wall of the outer shell, form a closed filling cavity.

[0009] High-temperature phase change microcapsule particles are filled within the sealed filling cavity. Each high-temperature phase change microcapsule particle consists of a high-temperature resistant inorganic encapsulation shell and a phase change material core material encapsulated within the shell. The inorganic encapsulation shell is made of materials such as alumina, silicon oxide, silicon carbide, or carbon materials, and is prepared using processes such as sol-gel method, spray drying method, or chemical vapor deposition method to ensure excellent chemical stability and mechanical strength under long-term high temperatures (e.g., >200℃ or even 500℃). The phase change material core material is selected from metal alloys with a phase change temperature higher than 100℃ (e.g., Al-Si alloy), molten salts (e.g., NaNO3-KNO3 eutectic salt, NaF, etc.), or high-temperature paraffin, with a latent heat of phase change of not less than 150 J / g to ensure high energy storage density. The microcapsule particles form interstitial channels for fluid flow. These high-temperature microcapsule particles are loosely packed within the cavity, creating a complex network of interconnected three-dimensional interstitial channels. By controlling the particle size (typically 10-500 μm) and packing density (with packing porosity controlled at 30%-60%), the size and tortuosity of these channels can be adjusted, thereby optimizing the fluid flow resistance and heat transfer area. The high-temperature resistant outer casing integrates quick-connect interfaces at both ends. These interfaces are standardized pipe fittings, such as clamp-type quick-connect couplings, flanges, or threaded joints. Their function is to enable quick and reliable connection and disconnection between the device and external high-temperature fluid source pipelines or low-temperature heat pipelines. High-temperature resistant rubber or metal gaskets are installed at the interfaces to ensure airtightness.

[0010] The inorganic high-temperature resistant shell is made of one or more composite materials selected from alumina, silicon oxide, silicon carbide, and carbon materials.

[0011] The high-temperature resistant outer shell can be designed as a double-layer structure. The inner layer is made of a high-temperature resistant material with good thermal conductivity (such as stainless steel, high-temperature alloy, or silicon carbide ceramic) to promote heat transfer from the fluid to the inside. The outer layer is made of thermal insulation material (such as ceramic fiber or aerogel felt) to reduce heat loss during heat storage and transfer. Temperature-sensitive color-changing coatings or patches can also be applied to the surface of the outer shell as temperature indicators to visually display the approximate temperature state inside the device (such as low temperature, phase transition, or high temperature saturation) through color changes.

[0012] The device adopts a modular design, with each device being a standard thermal storage unit. Depending on the flow rate and thermal storage capacity requirements of the actual application scenario, multiple identical devices can be connected in series (increasing the total pressure drop and heat exchange process, suitable for low-flow scenarios requiring deep cooling / heating) or in parallel (reducing flow resistance, suitable for high-flow scenarios requiring rapid processing) through external pipelines and matching T-junctions and four-way fittings, allowing for flexible system construction.

[0013] Based on the above-mentioned device, the present invention also provides a corresponding method for thermal energy storage and transfer, which mainly includes the following steps: (1) Heat Storage Stage: High-temperature fluid (gas or liquid) from heat sources such as industrial waste heat and engine exhaust is connected to the quick-connect interface of the device through an external insulated pipeline. The high-temperature fluid enters from the inlet and flows through the gap channels of the high-temperature phase change microcapsule particle layer under the pressure difference. Strong forced convection heat transfer occurs between the fluid and the particle surface, and the heat is rapidly transferred to the particles, causing the phase change material core material inside to absorb heat and melt (solid-liquid phase change). This process absorbs a large amount of sensible heat from the fluid, significantly reducing its temperature and achieving the purpose of cooling or waste heat recovery. The cooled fluid is discharged from the outlet. In this stage, it is necessary to control the fluid flow rate (e.g., 0.1-5 m / s) and Reynolds number (e.g., 50-2000) to balance the heat transfer efficiency and the flow pressure drop.

[0014] (2) Saturation judgment stage: Install a temperature sensor on the downstream pipeline of the fluid outlet of the device to monitor the outlet fluid temperature T in real time. out Simultaneously, monitor or know the inlet fluid temperature T. in When most of the phase change material in the device has completed its phase change and the heat storage is close to saturation, its cooling capacity decreases, and the outlet temperature gradually increases. A saturation threshold ΔT is set. sat (e.g., 5℃). When (T) is detected in - T out )<ΔT sat If the state of heat storage remains saturated for a period of time (e.g., 2-5 minutes), it can be determined that the device is saturated and needs to be replaced or moved.

[0015] (3) Disassembly and transfer stage: Close the pipeline valves on the heat source side and the system side, and use the convenient unlocking function of the quick connection interface (such as loosening the clamp and unscrewing the flange bolts) to completely disconnect the saturated heat storage device from the external pipeline.

[0016] (4) Heat release and utilization stage: The saturated device is transported to the location where heat is needed. The heat release method is flexibly selected according to the heat demand: (a) Heating fluid: If it is necessary to heat cryogenic fluids such as water or air, the device can be connected to the corresponding heat supply system through a quick-connect interface, so that the cryogenic fluid flows through the device in the opposite (or same) direction. The cryogenic fluid absorbs the latent heat released by the microcapsule solidification and is heated, while the device itself gradually cools and regenerates.

[0017] (b) Direct heating: If a device, space or container needs to be heated, it can be directly attached to the surface of the object or placed in the space where the temperature needs to be raised, and heat can be released through natural convection and thermal radiation.

[0018] (c) Immersion heat exchange: For liquid heating, the entire device can be simply immersed in a liquid storage tank (such as a water tank) to exchange heat with the liquid through the shell wall.

[0019] After the heat release is complete, the phase change material inside the device re-solidifies, returning to a state where it can store heat again, thus completing one working cycle.

[0020] The core innovation of this invention lies in: (1) Material innovation: The high-temperature PCM is encapsulated with an inorganic shell (such as a SiO2 / Al2O3 composite shell prepared by sol-gel method), which breaks through the limitation of poor temperature resistance of organic shells. This enables the device to be stably applied to medium and high temperature waste heat scenarios above 100℃ or even 500℃, thus extending its service life.

[0021] (2) Structural innovation: High-temperature resistant phase change microcapsules are integrated into a detachable shell in the form of a packed bed, creating a core heat storage unit that combines high-efficiency heat exchange, high-density heat storage and good mechanical stability.

[0022] (3) Application Model Innovation: A detachable and mobile application method of "heat storage-extraction-heat release" is proposed. The device achieves spatial and temporal decoupling of thermal energy storage and utilization, greatly improving application flexibility. This model is particularly suitable for scenarios with discontinuous heat generation or where the heat source and the heat consumption point are separated. Attached Figure Description

[0023] Figure 1 This is a simplified structural diagram of the present invention.

[0024] Figure 2 This is a schematic diagram illustrating the use of multiple device modules in series in this invention.

[0025] Figure 3 This is a schematic diagram of the drawer-type modular thermal storage device described in Embodiment 3 of the present invention.

[0026] The labels in the diagram are explained as follows: 1. Fluid inlet; 2. Fluid outlet; 3. Porous support structure; 4. Quick-connect interface; 5. High-temperature phase change microcapsule particles; 6. Inorganic encapsulation shell; 7. Phase change material core material; 8. High-temperature resistant outer shell (inner layer); 9. Thermal insulation layer (outer layer); 10. Temperature indicator; 11. Drawer-type outer shell frame; 12. Modular thermal storage tank; 13. Guide rail; 14. Tank handle / pull ring. Detailed Implementation

[0027] The following will refer to the appendices in the embodiments of the present invention. Figure 1-3The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Basic detachable thermal storage unit: This embodiment provides, as follows: Figure 1 The basic device shown.

[0029] The main body of the device consists of a cylindrical high-temperature resistant outer shell (inner layer) 8, a heat insulation layer 9, and high-temperature phase change microcapsule particles 5. The high-temperature resistant outer shell (inner layer) 8 is made of stainless steel tubing, and the heat insulation layer 9 is made of ceramic fiber insulation cotton. A reversible temperature-sensitive color-changing patch is attached to the surface of the outer shell as a temperature indicator 10. A fluid inlet 1 and a fluid outlet 2 are respectively opened at the center of both ends of the outer shell. Standard clamp-type quick-connect couplings are welded to both the inlet and outlet as quick connection interfaces 4, and the interfaces are embedded with fluororubber sealing rings.

[0030] Inside the outer casing, adjacent to the inner walls of the inlet and outlet, a 316L stainless steel microporous sieve plate is fixedly installed as a porous support structure 3, with a sieve plate pore size of 40 μm. The cavity formed between the two sieve plates is filled with high-temperature phase change microcapsule particles 5. In this embodiment, the microcapsules use an alumina / silica composite sol-gel shell as the inorganic encapsulation shell 6, and sodium fluoride (NaF) molten salt as the phase change material core material 7. The phase change temperature is approximately 995℃ (suitable for extremely high-temperature waste heat; in practical applications, a suitable phase change temperature PCM can be selected based on the heat source temperature). The microcapsule particle size ranges from 150-300 μm, and they are loaded using a vibration filling method. The measured packed bed porosity is approximately 45%.

[0031] As an independent module, the device has standardized quick-connect fittings at both its inlet and outlet, allowing for direct plug-in connection with compatible insulated hoses equipped with quick-connect plugs.

[0032] Method for recovering waste heat from engine coolant: This embodiment demonstrates the process of using the device described in Embodiment 1 to recover waste heat from the high-temperature coolant of a certain type of diesel engine.

[0033] System Connection: A branch pipe is drawn from the engine's high-temperature coolant (mainly composed of ethylene glycol aqueous solution, normal operating temperature approximately 95-120℃) circulation line. A high-temperature resistant hose with matching clamps at both ends is connected in series to this branch pipe to connect the heat storage device from Example 1. The device inlet is connected to the high-temperature side of the engine, and the outlet is connected to the coolant return line or an intermediate reservoir. During connection, the hose connector is aligned with the quick-connect interface 4 on the device and inserted, then secured with clamps; the process is quick and provides a reliable seal.

[0034] Thermal storage operation: The engine is started, and high-temperature coolant (approximately 110°C) flows through the device at a rate of approximately 0.5 m / s. The coolant passes through the interstitial channels of the high-temperature phase change microcapsule particles 5, transferring heat to the particles, causing the NaF phase change material to absorb heat and melt. The coolant is discharged after its outlet temperature drops to approximately 85°C, achieving auxiliary cooling and waste heat recovery. Operation continues until the coolant temperature at the device outlet rises to approximately 105°C (i.e., the temperature difference ΔT between the outlet and inlet is less than 5°C). A thermocouple temperature sensor installed on the outlet pipeline determines that the device's thermal storage is nearing saturation.

[0035] Disassembly and Heat Release: Close the upstream and downstream valves of the branch pipe, loosen the clamps, and quickly disassemble the device from the pipeline. At this time, the temperature indicator 10 on the device casing will show a high temperature. Immerse the disassembled saturated device entirely in a thermostatically insulated container filled with 20 liters of room temperature (approximately 20°C) water. The device casing exchanges heat with the cold water, and the internal NaF molten salt gradually solidifies, releasing its stored latent heat to heat the water in the container. After about 1 hour, the water temperature can rise to over 70°C, which can be used for cleaning, preheating, or other low-grade heat needs. The device is then cooled and regenerated, and the temperature indicator returns to a low-temperature color, ready for reuse.

[0036] Example 3: Drawer-type modular thermal storage system This embodiment provides an optimized solution that enables continuous online operation, such as... Figure 3 As shown.

[0037] The system includes a fixed drawer-type outer frame 11 with parallel guide rails 13 inside. Multiple independent modular thermal storage tanks 12 are mounted side-by-side on the guide rails like drawers. Each tank is essentially a variation of the device described in Embodiment 1, but its high-temperature resistant outer shell is designed in a flatter cuboid shape and has a tank handle / pull ring 14 on the outside for easy pulling out. The inlets and outlets of all tanks are connected in parallel to a main interface at the rear of the frame via pre-designed manifolds.

[0038] When the system is running, the high-temperature fluid flows simultaneously through all the tanks in their operating positions. Once a tank reaches saturation (determined by monitoring its branch outlet temperature), the corresponding inlet and outlet valves can be closed, and the tank can be smoothly pulled out of the frame along guide rail 13, like a drawer. Subsequently, a spare tank that has already undergone heat release and cooling regeneration elsewhere can be pushed into the empty position along the guide rail, and its valve opened. The entire process can be completed within minutes, enabling "hot-swappable" replacement of the heat storage units and ensuring the continuity of the main system's heat storage function. The extracted saturated tanks can be transported centrally to distant heat-using workshops, where they can be connected to cryogenic fluids for heat release via a similar manifold system, achieving large-scale, specialized transfer and cascade utilization of thermal energy.

Claims

1. A detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles, characterized in that, include: The high-temperature resistant outer shell is the pressure-bearing and sealing container of the entire device. It is cylindrical or cuboid in shape, and the two ends of the inner shell are provided with porous support structures. High-temperature phase change microcapsule particles are filled in a closed filling cavity. The high-temperature phase change microcapsule particles are all composed of a high-temperature resistant inorganic encapsulation shell and a phase change material core material encapsulated in the shell. The microcapsule particles form gap channels for fluid flow. The high-temperature microcapsule particles are filled in the cavity in a loosely stacked manner, and the particles form a complex three-dimensional interconnected gap channel. The high-temperature resistant housing has integrated quick-connect interfaces at both ends.

2. The detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles according to claim 1, characterized in that: The high-temperature resistant outer shell is equipped with a fluid inlet and a fluid outlet, located at the central axis of both ends of the high-temperature resistant outer shell, to ensure that the fluid can pass evenly through the entire cross-section of the filling layer.

3. A detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles according to claim 1 or 2, characterized in that: The high-temperature resistant outer shell is designed with a double-layer structure. The inner layer is made of high-temperature resistant and thermally conductive materials, including stainless steel, high-temperature alloys, or silicon carbide ceramics, to promote heat transfer from the fluid to the inside. The outer layer is made of thermal insulation materials, including ceramic fibers or aerogel felt, to reduce heat loss during heat storage and transfer. The surface of the outer shell is equipped with temperature-sensitive color-changing paint or patches as temperature indicators, which intuitively display the internal temperature status of the device through color changes.

4. The detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles according to claim 1, characterized in that: The porous support structure supports the high-temperature phase change microcapsule particle layer filled inside, preventing blockage or damage to the flow channel due to fluid impact or self-weight accumulation; the porous support structure acts as a filter barrier, with the micropore diameter designed to be smaller than the minimum particle size of the filled microcapsule particles, preventing particles from being lost with the fluid; the porous support structure and the inner wall of the outer shell together form a closed filling cavity.

5. A detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles according to claim 1, characterized in that: The phase change material is selected from one or more combinations of metal alloys, molten salts, or high-temperature paraffins, with a minimum phase change temperature of 100℃ and a latent heat of phase change of not less than 150J / g.

6. A detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles according to claim 1, characterized in that: The microcapsules have a particle size of 10-500 μm, a filling density of 30-60%, and form a three-dimensional interstitial channel with an equivalent diameter of 50-500 μm.

7. A detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles according to claim 1, characterized in that: The device adopts a modular design, with each device being a standard thermal storage unit. Based on the flow rate and thermal storage capacity requirements of the actual application scenario, multiple identical devices can be connected in series or in parallel through external pipelines and matching tees and crosses.

8. An application method for a detachable heat storage and heat exchange device based on high-temperature resistant phase change microcapsule particles, characterized in that: Includes the following steps: Heat storage stage: High-temperature fluid from industrial waste heat and engine exhaust is connected to the quick connection interface of the device through an external insulated pipeline; the high-temperature fluid enters from the inlet and flows through the gap channels of the high-temperature phase change microcapsule particle layer under the pressure difference drive; strong forced convection heat transfer occurs between the fluid and the particle surface, and the heat is rapidly transferred to the particles, causing the internal phase change material core material to absorb heat and melt; the cooled fluid is discharged from the outlet. Saturation determination stage: Install a temperature sensor on the downstream pipeline of the fluid outlet of the device to monitor the outlet fluid temperature T in real time. out Simultaneously, monitor or know the inlet fluid temperature T. in When most of the phase change material in the device has completed its phase change and the heat storage is close to saturation, the cooling capacity decreases and the outlet temperature gradually increases; a saturation judgment threshold ΔT is set. sat When (T) is detected in -T out ) < ΔT sat If the state continues for a period of time, it is determined that the heat storage device is saturated and needs to be replaced or moved. Disassembly and transfer phase: Close the pipeline valves on the heat source side and the system side, and use the convenient unlocking function of the quick connection interface to completely disconnect the saturated heat storage device from the external pipeline; Heat release utilization stage: The saturated device is transported to the location where heat is needed; after the heat release is completed, the phase change material inside the device is re-solidified, restoring it to a state where it can store heat again, thus completing one working cycle.

9. The method according to claim 8, characterized in that: Heat release methods include: Heating fluid: If it is necessary to heat water or air, the device is connected to the corresponding heat supply pipeline system through the quick connection interface, so that the low temperature fluid flows through the device in the opposite direction; the low temperature fluid absorbs the latent heat released by the microcapsule solidification and is heated, while the device itself gradually cools and regenerates. Direct heating: If it is necessary to heat a piece of equipment, space or container, the device is directly attached to the surface of the object or placed in the space where the temperature needs to be raised, and heat is released through natural convection and thermal radiation. Immersion heat exchange: For liquid heating, the entire device is immersed in the liquid storage tank, and heat is exchanged between the device and the liquid through the shell wall.

10. The method according to claim 9, characterized in that: During the thermal storage stage, the liquid flow rate is 0.1-5 m / s, and the Reynolds number is controlled within the range of 50-2000 to ensure sufficient heat exchange.

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