Composite modified particle and heat storage tank

Abstract

The invention relates to a composite modified particle and a heat storage tank, the composite modified particle adopts a metal material as a packaging shell, and in the long-term frequent heat storage and release circulation process, a traditional heat storage medium is easy to crack into powder due to the thermal stress effect, so that the heat storage performance is reduced, and a pipeline is possibly blocked. The composite modified particles are effectively prevented from cracking into powder through a metal packaging technology and a metal shell, so that the composite modified particles can maintain a stable particle form in a complex thermal environment. The long-time stable and reliable operation of the solar photo-thermal heat storage system is ensured, and the heat exchange efficiency is higher. The composite modified particle comprises a metal shell, heat storage particles and a condensation heat transfer material, a hollow inner cavity is formed in the metal shell, the heat storage particles are arranged in the inner cavity of the metal shell, and the condensation heat transfer material is arranged in the inner cavity of the metal shell.

Description

Technical Field

[0001] The present invention relates to the field of heat storage technology, and specifically provides a composite modified particle and a heat storage tank. Background Art

[0002] Solar energy has become a highly sought-after renewable energy source due to its clean, pollution-free, abundant reserves, and wide distribution. Currently, application technologies based on solar photovoltaic and solar thermal conversion have made significant progress in both research and practical application. Among the many ways to utilize solar energy, solar thermal power generation has garnered widespread attention due to its outstanding advantages of being environmentally friendly, relatively mature technology, and stable power output. However, the intermittent and discontinuous supply of solar energy makes it particularly necessary to install heat storage devices during the utilization of solar thermal energy. This allows for the storage of energy when there is excess solar energy and its release when needed.

[0003] Currently, dual-tank thermal storage systems are a common commercial heat storage method in solar thermal power plants. However, these systems suffer from high thermal fluid consumption, large floor space requirements, and high construction costs. In contrast, single-tank thermal storage systems, with their simple structure, small footprint, and low investment costs, have gained popularity in the industry.

[0004] To further reduce the cost of energy storage systems, some existing energy storage systems use rock particles, industrial byproduct particles, and other energy carriers, deposited within a single-tank thermocline tank for direct heat exchange with a flowing medium. During heat storage, the flowing medium transfers heat to the particles, and during heat release, the particles transfer heat to the flowing medium, forming a particle-packed bed thermocline tank. However, the particles are susceptible to cracking and pulverization under the flow of the flowing medium and the long-term storage and release cycles. This reduces the average particle size of the packed bed, impairs fluid permeability, and increases fluid flow resistance, affecting the safe and stable operation of the tank during the storage and heat exchange process. Furthermore, the varying shapes of these particles and their poor thermal conductivity make sufficient heat exchange with the flowing medium difficult, leading to uneven temperatures within the tank and low heat exchange efficiency. Summary of the Invention

[0005] In response to the above problems, the present invention provides a composite modified particle and a heat storage tank. The composite modified particle is not easily cracked into powder and has higher heat exchange efficiency.

[0006] One aspect of the present invention provides a composite modified particle, comprising a metal shell, heat storage particles and a condensation heat transfer material, wherein a hollow inner cavity is formed inside the metal shell, the heat storage particles are built into the inner cavity of the metal shell, and the condensation heat transfer material is built into the inner cavity of the metal shell.

[0007] According to this technical solution, first, the composite modified particles use a metal material as the encapsulation shell. During long-term and frequent heat storage and release cycles, traditional heat storage media are prone to cracking and powdering due to thermal stress, resulting in a decrease in heat storage performance and possible blockage of pipelines. However, the composite modified particles use metal encapsulation technology, and the metal shell effectively prevents the particles from cracking and powdering, allowing them to maintain a stable particle shape in complex thermal environments. This extends the service life of the heat storage particles, reduces the cost and time of frequent material replacement due to particle damage, ensures the long-term stable and reliable operation of the solar thermal heat storage system, and provides a strong guarantee for the continuous and stable supply of energy.

[0008] Secondly, the metal shell has higher thermal conductivity and smaller heat transfer resistance. Furthermore, the interior of the metal shell is filled with condensation heat transfer material. In the solar thermal system, when storing heat, the metal shell transfers heat to the inside, and the condensation heat transfer material undergoes phase change and vaporization, and the heat can be quickly and efficiently transferred to the composite modified particles; and when releasing heat, the heat of the composite modified particles is condensed through the condensation heat transfer material and quickly transferred to the metal shell, so that the heat can be quickly transferred to the flowing medium. Compared with traditional heat storage media, the composite modified particles have a faster heat transfer speed and higher efficiency, which can effectively shorten the heat storage and heat release time, ensure that the solar thermal storage system fully absorbs heat during the day, and stably releases heat under no-light conditions such as at night or on cloudy days, thereby improving the overall performance of the solar thermal storage system and achieving efficient energy utilization.

[0009] As an optional technical solution, a plurality of heat storage particles are evenly distributed in the condensation heat transfer material.

[0010] This optional technical solution evenly distributes the heat storage particles within the condensation heat transfer material, increasing the contact area between the particles and the condensation heat transfer material, thereby improving heat exchange efficiency. Furthermore, it evenly distributes heat within the composite modified particles, maintaining a stable structure during long-term thermal cycles and further enhancing their resistance to cracking and pulverization.

[0011] As an optional technical solution, the inner cavity includes a heat transfer cavity and a heat storage cavity that are independent of each other. The heat transfer cavity is formed around the heat storage cavity. The condensed heat transfer material is filled in the heat transfer cavity, and the heat storage particles are filled in the heat storage cavity.

[0012] According to this optional technical solution, by accommodating the condensation heat transfer material and the heat storage particles in layers through the heat transfer cavity and the heat storage cavity structure, the heat storage particles can completely conduct heat with the metal shell through the condensation heat transfer material, resulting in a larger heat transfer area and higher heat transfer efficiency.

[0013] As an optional technical solution, the shape of the composite modified particles is spherical, spindle-shaped or teardrop-shaped.

[0014] According to this optional technical solution, the composite heat storage particles in the shape of a sphere, a spindle or a teardrop have better fluidity, generate less resistance when in contact with the flowing working fluid, reduce the scouring of the composite modified particles by the flowing working fluid, further ensure structural stability, and improve the safety and stability of the equipment during the heat exchange process.

[0015] Moreover, the above-mentioned shape filling can ensure uniform gap distribution of particles in the storage tank, while ensuring the gaps between particles, so as to improve the overall heat storage and heat release performance of the heat storage tank, and maintain a stable structure during long-term thermal cycles, preventing problems such as local overheating or uneven cooling caused by particle movement or aggregation.

[0016] As an optional technical solution, the particle size of the composite modified particles is 50-100 mm.

[0017] According to this optional technical solution, the composite modified particles with a particle size of 50-100 mm can ensure good fluidity and filling performance in the stacked bed. At the same time, the size of the heat transfer gap between the composite modified particles is maintained in a relatively preferred range, ensuring that the heat exchange between the composite modified particles and the working fluid is sufficiently uniform, so as to improve the overall heat transfer efficiency and temperature distribution uniformity. In addition, it can reduce the resistance between the working fluid and the particles, prevent the fluid permeability from deteriorating, and further improve the safety and stability of the equipment during the heat exchange process.

[0018] As an optional technical solution, the heat storage particles are one or more combinations of metal oxides, metal hydrides, rocks, gravel, and concrete.

[0019] According to this optional technical solution, the heat storage particles are made of any one or more of the above materials, which can make them have high thermal stability. For example, as the basic material for heat storage, rock particles have high thermal stability, can maintain structural stability within a large temperature range, withstand repeated thermal shocks, and provide basic thermal capacity for the heat storage process.

[0020] As an optional technical solution, the particle size of the heat storage particles is 0.5-5 mm.

[0021] According to this optional technical solution, heat storage particles with a particle size of 0.5-5 mm can fully absorb and release heat, thereby improving heat exchange efficiency.

[0022] As an optional technical solution, the phase change temperature of the condensation heat transfer material is 110-218°C.

[0023] According to this optional technical solution, the phase change temperature of the condensation heat transfer material is 110-218°C, so that the phase change temperature of the condensation heat transfer material matches the operating temperature range of the heat storage tank, ensuring that phase change can fully occur during the heat storage and heat release process, thereby efficiently absorbing and releasing heat, and further improving the heat exchange efficiency of the composite modified particles.

[0024] As an optional technical solution, the condensation heat transfer material is one or more combinations of methanol, toluene, and naphthalene.

[0025] According to this optional technical solution, first, one or more combinations of methanol, toluene, and naphthalene are selected as condensation heat transfer materials, which can undergo phase change within the operating temperature range of the heat storage system, and significantly improve the heat exchange performance of the composite modified particles through condensation heat transfer.

[0026] Secondly, during the condensation process, methanol, toluene, and naphthalene vapors form droplets on the condensation surface and quickly fall off. The contact area between the droplets and the condensation surface is small, resulting in low thermal resistance, which greatly improves heat transfer efficiency and quickly releases a large amount of latent heat. Compared with conventional heat transfer materials, its heat transfer coefficient can be increased by several times or even dozens of times, ensuring the high efficiency and rapidity of the heat storage system during the condensation heat transfer process. This efficient heat transfer performance enables the heat storage system to complete a large amount of heat exchange in a relatively short period of time, effectively improving the overall energy efficiency of the system.

[0027] Another aspect of the present invention provides a heat storage tank, comprising a tank body having a first opening and a second opening, and the tank body is internally filled with the above-mentioned composite modified particles.

[0028] According to this optional technical solution, the heat storage tank has the composite modified particles, which also has its beneficial technical effects, and can significantly improve the heat exchange efficiency and heat storage density, and optimize the system performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a heat storage tank provided in an embodiment of the present invention and an enlarged view of the composite modified particles in the heat storage tank.

[0030] Figure 2 It is a schematic diagram of the cross-sectional structure of another composite modified particle provided in an embodiment of the present invention.

[0031] Explanation of the reference numerals: 10 - metal shell; 1 - heat storage particles; 2 - condensation heat transfer material; 3 - inner cavity; 4 - first opening; 5 - second opening. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] It should be noted that in this embodiment, the term "condensation heat transfer material" refers to a fluid material that undergoes condensation / evaporation phase change within a certain temperature range. Through the phase change of the "condensation heat transfer material", a large amount of heat can be quickly absorbed / released, thereby achieving rapid heat transfer.

[0034] Figure 1 Schematic diagram of the structure of a heat storage tank provided in an embodiment of the present invention. Figure 1 As shown, the heat storage tank is formed as a hollow tank body having a first opening 4 and a second opening 5 for allowing the flowing working medium to flow in / out. Figure 1 The example in the figure shows a case where the first opening 4 and the second opening 5 are respectively provided at the top and bottom of the heat storage tank, but the present invention is not limited thereto. The first opening 4 and the second opening 5 may also be provided on the left and right sides of the tank body or at any other location. In this embodiment, when storing heat, the hot fluid flows in through the first opening 4, and the cold fluid after heat exchange flows out through the second opening 5. When releasing heat, the cold fluid flows in through the second opening 5, and the hot fluid after heat exchange flows out through the first opening 4.

[0035] The shape and type of the tank body are not limited here, and can be formed into a hollow cylinder, a sphere, a cuboid, etc. Here, a cylindrical stacked bed thermostatic layer particle heat storage tank is used as an example. In this heat storage tank, the composite modified particles are built into the interior of the tank body, wherein, optionally, a flow equalizer is provided in the tank body near the first opening 4 and near the second opening 5, and the composite modified particles are arranged between the two flow equalizers. In particular, the aperture of the flow equalizer can be smaller than the particle size of the composite modified particles, thereby being able to play a role in limiting the movement of the composite modified particles. At the same time, the flow state of the flowing working medium can also be adjusted, so that the flowing working medium can exchange heat with the composite modified particles more evenly, thereby improving the heat exchange efficiency.

[0036] Furthermore, a metal bracket (not shown) for supporting the modified particles can be installed at the bottom of the heat storage tank cavity 3. The support of the metal bracket can improve the stability of the composite modified particles during flushing, thereby increasing the service life of the heat storage tank as a whole.

[0037] The structure of the composite modified particles within the heat storage tank is further described below with reference to the accompanying drawings. It should be noted that while this embodiment uses the composite modified particles within the heat storage tank as an example, this does not limit the use of the composite modified particles. The composite modified particles can be used alone to store / release heat or placed in any container for heat storage / release.

[0038] Figure 1 A cross-sectional view of the composite modified particles in the heat storage tank is also shown. Figure 1 As shown, the composite modified particles include a metal shell 10, heat storage particles 1 and condensation heat transfer materials 2.

[0039] A hollow inner cavity 3 is formed inside the metal shell 10 . The metal shell 10 is preferably made of a material with high thermal conductivity, such as copper, aluminum, iron, or other metal materials with a thermal conductivity of ≥10 W / (m·K).

[0040] The heat storage particles 1 and the condensation heat transfer material 2 are both built into the inner cavity 3 of the metal shell 10. The heat storage particles 1 and the condensation heat transfer material 2 can be mixed in the same inner cavity 3, or the heat storage particles 1 and the condensation heat transfer material 2 can also be respectively arranged in two different inner cavities 3, which is not limited here.

[0041] The heat storage particles 1 can be any solid particles made of any heat storage material with a high specific heat capacity. Optionally, the heat storage particles 1 are one or more combinations of metal oxides, metal hydrides, rocks, gravel, and concrete. These heat storage materials have high thermal stability, with rock particles exhibiting high thermal stability, maintaining structural stability over a wide temperature range and withstanding repeated thermal shocks. These provide the fundamental thermal capacity for the heat storage process, are readily available, and are environmentally friendly, making them suitable for large-scale heat storage.

[0042] Furthermore, the particle size of the heat storage particles 1 can be 0.5-5 mm. The heat storage particles 1 with a particle size of 0.5-5 mm can fully absorb and release heat, thereby improving heat exchange efficiency.

[0043] The condensation heat transfer material 2 can be a fluid material that can quickly transfer heat through phase change (condensation and evaporation). In addition, based on the heat storage temperature range of the heat storage particles 1, condensation heat transfer materials 2 with different phase change temperatures can be adaptively selected for filling to ensure that phase change can fully occur during the heat storage and heat release process, thereby efficiently absorbing and releasing heat, and further improving the heat exchange efficiency of the composite modified particles. As an example, the phase change temperature of the condensation heat transfer material 2 can be 110 to 218°C. This phase change temperature range can better match the storage / release temperature in a general stacked bed thermostatic layer particle heat storage tank.

[0044] Furthermore, the condensation heat transfer material 2 is a combination of one or more of methanol, toluene, and naphthalene. During the condensation process, the vapors of methanol, toluene, and naphthalene form droplets on the condensation surface and quickly fall off. The contact area between the droplets and the condensation surface is small, and the thermal resistance is small, thereby greatly improving the heat transfer efficiency and quickly releasing a large amount of latent heat. Compared with conventional heat transfer materials, its heat transfer coefficient can be increased by several times or even dozens of times, ensuring the high efficiency and rapidity of the heat storage system during the condensation heat transfer process. The efficient heat transfer performance enables the heat storage system to complete a large amount of heat exchange in a relatively short period of time, effectively improving the overall energy efficiency of the system.

[0045] Specifically, when the heat storage tank is storing heat, the hot fluid enters the particle accumulation bed inclined temperature layer heat storage tank through the first opening 4, and after being equalized by the flow equalizer, it contacts and exchanges heat with the composite modified particles. These composite modified particles are made of high thermal conductivity metal materials that encapsulate heat storage particles 1 such as rocks and condensation heat transfer materials 2. The metal shell 10, with its high thermal conductivity, quickly transfers the heat of the hot fluid to the condensation heat transfer material 2. The condensation heat transfer material 2 undergoes a phase change in the heat storage temperature range, from liquid to gas, and the cold fluid after heat exchange flows out of the heat storage tank. In this process, the condensation heat transfer material 2 efficiently transfers and stores heat in the heat storage particles 1 such as rocks sealed inside. The heat is evenly distributed and the heat storage efficiency is high. At the same time, the condensation heat transfer material 2 absorbs a large amount of latent heat in the process, thereby increasing the heat storage density.

[0046] When the heat storage tank releases heat, the cold fluid enters the particle-packed bed thermostatic layer heat storage tank through the second opening 5. After being equalized by the flow equalizer, it comes into contact with the composite modified particles for heat exchange. The heat storage particles 1, such as rocks, store heat and transfer it to the condensing heat transfer material 2. The condensing heat transfer material 2 rapidly condenses into droplets in the metal shell and releases heat, transferring the heat stored in the heat storage particles 1, such as rocks, to the cold fluid. The high thermal conductivity of the metal shell 10 and the phase change condensation of the condensing heat transfer material 2 promote heat transfer, rapidly raising the temperature of the cold fluid. After heat exchange, the hot fluid carries the heat out of the heat storage tank and provides heat to the external system.

[0047] In this embodiment, the composite modified particles utilize a metal shell as their encapsulation. During long-term, frequent heat storage and release cycles, traditional heat storage media can easily crack and pulverize due to thermal stress, resulting in decreased heat storage performance and potential pipe clogging. However, the composite modified particles utilize metal encapsulation technology, with the metal shell 10 effectively preventing the particles from cracking and pulverizing, allowing them to maintain a stable particle shape in complex thermal environments. This extends the service life of the heat storage particles 1, reduces the cost and time associated with frequent material replacement due to particle breakage, ensures the long-term stable and reliable operation of the solar thermal energy storage system, and provides a strong guarantee for a continuous and stable energy supply.

[0048] Secondly, the metal shell 10 has a higher thermal conductivity and a smaller heat transfer resistance. Furthermore, the interior of the metal shell 10 is filled with a condensation heat transfer material. In the solar thermal system, when storing heat, the metal shell 10 transfers heat to the interior, and the condensation heat transfer material 2 undergoes a phase change and vaporization, and the heat can be quickly and efficiently transferred to the composite modified particles; and when releasing heat, the heat of the composite modified particles is condensed through the condensation heat transfer material 2 and quickly transferred to the metal shell 10, so that the heat can be quickly transferred to the flowing medium. Compared with traditional heat storage media, the composite modified particles have a faster heat exchange speed and higher efficiency, which can effectively shorten the heat storage and heat release time, ensure that the solar thermal storage system fully absorbs heat during the day, and stably releases heat under no-light conditions such as at night or on cloudy days, thereby improving the overall performance of the solar thermal storage system and achieving efficient energy utilization.

[0049] Optionally, the composite modified particles may be spherical, conical, or teardrop-shaped. The particle size may be 50-100 mm. On the one hand, spherical, conical, or teardrop-shaped particles with moderate particle sizes exhibit good fluidity, generating less resistance when in contact with a flowing medium, thereby reducing the scouring of the composite modified particles by the flowing medium.

[0050] On the other hand, these composite modified particles are packed in the heat storage tank in the form of a stacked bed. To ensure good heat transfer and fluidity of the flowing medium, a certain amount of space between the particles is required. Therefore, using composite modified particles of the above size and shape to fill the tank can ensure a uniform distribution of particles in the tank, while ensuring the gaps between the particles, thereby improving the overall heat storage and heat release performance of the heat storage tank, and maintaining a stable structure during long-term thermal cycles, preventing problems such as local overheating or uneven cooling caused by particle movement or aggregation.

[0051] Among them, in some specific embodiments, such as Figure 1 As shown, multiple heat storage particles 1 and condensation heat transfer materials 2 are uniformly mixed in the inner cavity 3 of the metal shell 10. That is, multiple heat storage particles 1 are uniformly distributed in the condensation heat transfer material 2. It should be noted that Figure 1 The example in the figure shows a case where the metal shell 10 has one inner cavity 3, but in some other embodiments, the metal shell 10 has multiple inner cavities 3, and each inner cavity 3 is mixed with heat storage particles 1 and condensation heat transfer material 2 at the same time, which also falls within the scope of protection of the present invention.

[0052] In this embodiment, by evenly distributing the heat storage particles 1 within the condensation heat transfer material 2, the contact area between the heat storage particles 1 and the condensation heat transfer material 2 is increased, thereby improving heat exchange efficiency. Furthermore, the heat distribution within the composite modified particles is uniform, maintaining a stable structure during long-term thermal cycles and further enhancing their resistance to cracking and pulverization.

[0053] In other specific embodiments, Figure 2 As shown, an inner cavity 3 of the metal shell 10 can include mutually independent heat transfer and heat storage cavities. The heat transfer cavity surrounds the heat storage cavity, which is filled with condensed heat transfer material 2 and heat storage particles 1. By accommodating the condensed heat transfer material 2 and heat storage particles 1 in a layered structure, the heat storage particles 1 can fully conduct heat to the metal shell 10 through the condensed heat transfer material 2, resulting in a larger heat transfer area and higher heat exchange efficiency.

[0054] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite modified particle, characterized in that: include: A metal shell having a hollow inner cavity formed therein; Heat storage particles are built into the inner cavity of the metal shell; Condensation heat transfer material is built into the inner cavity of the metal shell.

2. The composite modified particles according to claim 1, characterized in that The plurality of heat storage particles are evenly distributed in the condensation heat transfer material.

3. The composite modified particles according to claim 1, characterized in that The inner cavity includes a heat transfer cavity and a heat storage cavity which are independent of each other. The heat transfer cavity is formed around the heat storage cavity. The condensed heat transfer material is filled in the heat transfer cavity, and the heat storage particles are filled in the heat storage cavity.

4. The composite modified particles according to any one of claims 1 to 3, characterized in that: The composite modified particles are in the shape of a sphere, a spindle or a droplet.

5. The composite modified particles according to any one of claims 1 to 3, characterized in that: The particle size of the composite modified particles is 50-100 mm.

6. The composite modified particles according to claim 5, characterized in that The heat storage particles are one or more combinations of metal oxides, metal hydrides, rocks, gravel, and concrete.

7. The composite modified particles according to claim 6, characterized in that The particle size of the heat storage particles is 0.5-5 mm.

8. The composite modified particles according to any one of claims 1 to 3, characterized in that: The phase change temperature of the condensation heat transfer material is 110-218°C.

9. The composite modified particles according to claim 8, characterized in that The condensation heat transfer material is one or more combinations of methanol, toluene and naphthalene.

10. A heat storage tank, comprising a tank body, wherein the tank body has a first opening and a second opening, wherein: The tank body contains the composite modified particles according to any one of claims 1 to 9.

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