A phase change buffer energy storage device

Abstract

The utility model provides a kind of phase change buffer energy storage device, including device ontology, high temperature area, thermocline regulating function layer and low temperature area are sequentially arranged from top to bottom in device ontology;High temperature area stores high temperature heat storage medium, low temperature area stores low temperature heat storage medium, thermocline regulating function layer sequentially includes small hole composite layer, baffle and large hole composite layer from top to bottom, small hole composite layer includes small hole skeleton and the first phase change material for filling small hole skeleton, large hole composite layer includes large hole skeleton and the second phase change material for filling large hole skeleton, the aperture of small hole composite layer is less than the aperture of large hole composite layer, the aperture of baffle is less than the aperture of small hole composite layer.The scheme core is in introducing a kind of thermocline regulating function layer as the partition and heat management core of high temperature area and low temperature area, for solving the problem that thermocline layer is difficult to control, can integrate "heat storage" and "anti-solidification" function, fundamentally overcome the defects of prior art.

Description

Technical Field

[0001] This utility model relates to the field of thermal energy storage technology, specifically to a phase change buffer energy storage device. Background Technology

[0002] Currently, energy structure transformation and efficient utilization of renewable energy have become the core directions of development in the energy sector. This is especially true for high-energy-consuming public buildings with dense populations and complex functions (such as hotels), where the low-carbon transformation and energy efficiency improvement of their energy systems have become core tasks for the industry's green development. These buildings not only face long-term high energy demands for air conditioning, heating, hot water supply, and kitchen equipment, but their traditional energy systems (such as gas boilers and electric heating) also suffer from high carbon emissions and fragmented energy utilization. Therefore, technological innovation is urgently needed to achieve the dual goals of "carbon reduction" and "efficiency improvement."

[0003] Thermal energy storage technology (especially molten salt thermal energy storage technology) is perfectly suited to meet the key needs of energy systems in high-energy-consuming public buildings (such as hotel energy systems) due to its core advantages of high thermal density, wide operating temperature range, and good long-term thermal stability. On the one hand, high-energy-consuming public buildings generate a large amount of recoverable high-temperature heat energy during daily operation (such as waste heat from kitchen cooking, condensation heat from air conditioning systems, and surplus heat from hot water preparation). Molten salt can efficiently absorb and store this dispersed waste heat, avoiding energy waste. On the other hand, for the concentrated energy demand of high-energy-consuming public buildings during peak periods (such as morning and evening hot water peaks and winter heating peaks), the stored high-temperature molten salt can release heat on demand, replacing part of the fossil fuel consumption, thus reducing carbon emissions and alleviating energy supply pressure.

[0004] However, existing thermal storage technologies (especially molten salt thermal storage technology) all have certain technical problems when applied to energy systems of high-energy-consuming public buildings with dense populations and complex functions (such as hotel energy systems), which are summarized as follows: The core design feature of existing dual-tank thermal storage systems lies in the use of two completely independent tanks to store cold and hot molten salt, respectively. This approach directly leads to a significant increase in tank material usage, floor space, piping systems, and supporting equipment, resulting in extremely high total system investment costs and becoming one of the core bottlenecks restricting cost reduction in molten salt thermal storage technology. Furthermore, the two tanks have a huge heat loss surface area, leading to significant heat loss during system operation.

[0005] Existing single-tank technology mainly achieves this through "layered thermal storage," creating a temperature gradient between upper and lower layers within the same tank to prevent direct mixing of hot and cold salt. However, this technology has extremely high requirements for tank height and feed position accuracy, and the layered interface is easily disrupted by disturbances, resulting in high heat loss, low thermal storage efficiency, and significant difficulty in controlling the thermocline.

[0006] Existing single-tank all-phase change material filling schemes have a series of key technical challenges, such as low overall heat exchange rate inside the tank, limited charging and discharging power, and long response time. These challenges make it difficult for the system to match the characteristics of the heat source and the energy demand in practical applications, thus restricting the practical value and economy of the thermal storage system.

[0007] Existing single-tank technology suffers from insufficient space utilization. Simply separating the hot molten salt section from the cold molten salt section would lead to re-stratification of the hot and cold molten salt sections within their respective spaces, resulting in larger longitudinal temperature gradients and impacting the energy storage stability and output flexibility of the single tank. Furthermore, single-tank systems rely on stable thermal stratification within the tank to separate the "charging" and "discharging" functions. Inlet / outlet disturbances, pump pulsations, natural convection, or heat exchanger operation can all cause interlayer mixing, reducing usable energy storage and system efficiency.

[0008] Therefore, there is an urgent need to develop a new type of single-tank thermal storage system to fundamentally overcome the shortcomings of existing technologies. Utility Model Content

[0009] In view of the deficiencies in the existing technology, the purpose of this utility model is to provide a phase change buffer energy storage device. Its core lies in introducing a temperature jump regulation functional layer as the core of the isolation and thermal management between the high temperature zone and the low temperature zone, which is used to solve the problem of the difficulty in controlling the temperature jump layer. It can integrate the functions of "heat storage" and "anti-condensation" and fundamentally overcome the deficiencies of the existing technology.

[0010] This utility model provides a phase change buffer energy storage device, including a device body. From top to bottom, the device body contains a high-temperature zone, a temperature rise regulation functional layer, and a low-temperature zone. The high-temperature zone stores a high-temperature heat storage medium, and the low-temperature zone stores a low-temperature heat storage medium. The temperature rise regulation functional layer, from top to bottom, includes a small-pore composite layer, a partition, and a large-pore composite layer. The small-pore composite layer includes a small-pore skeleton and a first phase change material for filling the small-pore skeleton. The large-pore composite layer includes a large-pore skeleton and a second phase change material for filling the large-pore skeleton. The first phase change material and the second phase change material may be the same or different. The pore size of the small-pore composite layer is smaller than that of the large-pore composite layer, and the pore size of the partition is smaller than that of the small-pore composite layer.

[0011] Furthermore, the volume of the high-temperature zone accounts for 20%-30% of the volume of the device body, the temperature rise regulation functional layer accounts for 40%-50% of the volume of the device body, and the volume of the low-temperature zone accounts for 25%-35% of the volume of the device body.

[0012] Furthermore, the thickness of the small-pore composite layer accounts for 25% of the total thickness of the temperature regulating functional layer, the thickness of the partition accounts for 5% of the total thickness of the temperature regulating functional layer, and the thickness of the large-pore composite layer accounts for 70% of the total thickness of the temperature regulating functional layer.

[0013] Furthermore, the pore size of the microporous composite layer is 10-500 μm, the pore size of the macroporous composite layer is 5-100 mm, and the pore size of the partition is 1-5 μm.

[0014] Furthermore, the porosity of the small-pore composite layer is 30-40%, and the porosity of the large-pore composite layer is 70%-80%.

[0015] Furthermore, a floating adjustment ring is also provided within the device body, the floating adjustment ring being slidably connected to the inner wall of the device body, and the temperature jump adjustment functional layer being disposed within the floating adjustment ring.

[0016] Furthermore, the small-pore composite layer is a small-pore ceramic-phase change material composite layer, the large-pore composite layer is a large-pore ceramic-phase change material composite layer, and the partition is a ceramic transition layer.

[0017] Furthermore, the device body includes a top cover, a tank and a base arranged sequentially from top to bottom, and the tank is provided with an inner wall layer, an outer wall layer and a heat insulation layer arranged sequentially from the inside to the outside; The lower end of the top cover is provided with a high-temperature zone flow equalizer, which is connected to the input end of the high-temperature heat storage medium. The high-temperature zone is also provided with a high-temperature heat storage medium outlet for outputting the high-temperature heat storage medium. The upper end of the base is provided with a low-temperature zone flow equalizer, which is connected to the input end of the low-temperature thermal storage medium. The low-temperature zone is also provided with a low-temperature thermal storage medium outlet for outputting the low-temperature thermal storage medium.

[0018] Furthermore, the high-temperature heat storage medium input end is located on the top cover, and the high-temperature heat storage medium outlet is located at one end of the high-temperature zone near the temperature jump regulating functional layer; the low-temperature heat storage medium input end is located at one end of the low-temperature zone near the temperature jump regulating functional layer, and the low-temperature heat storage medium outlet is located at one end of the low-temperature zone near the base. A high-temperature thermal storage medium circulation pump is also installed on the pipeline connected to the outlet of the high-temperature thermal storage medium, and a low-temperature thermal storage medium circulation pump is also installed on the pipeline connected to the outlet of the low-temperature thermal storage medium.

[0019] Furthermore, the low-temperature zone is also equipped with at least one electric heater.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. This utility model adopts a single-tank design. The low-temperature heat storage medium and the high-temperature heat storage medium (such as cold and hot molten salt) are integrated into a single tank. Compared with the dual-tank design, the footprint and tank material usage of this energy storage device can be reduced by about 50%, which greatly simplifies the structure of the energy storage system and significantly reduces the total investment cost of the project.

[0021] 2. This utility model abandons metal encapsulation, allowing the heat storage medium to directly contact the temperature rise regulating functional layer. That is, the heat storage medium directly contacts the porous skeleton filled with phase change material (such as a porous ceramic skeleton filled with phase change material). The heat transfer path is simplified to high-temperature heat storage medium - temperature rise regulating functional layer - low-temperature heat storage medium (such as hot molten salt - porous ceramic - phase change material composite layer - cold molten salt). It utilizes the large specific surface area of ​​porous materials for heat exchange, which reduces the heat transfer resistance compared to the prior art, thereby improving the charging and discharging power and rate. 3. This utility model uses porous ceramics with stable chemical properties and high mechanical strength as the PCM carrier and support structure. Since ceramic materials have the advantages of high temperature resistance and corrosion resistance, and their compatibility is better than that of metals, this utility model can fundamentally solve the PCM leakage problem and improve the system reliability and lifespan compared with the prior art.

[0022] 4. This utility model uses a solid-phase temperature-regulating functional layer (such as a gradient porous ceramic-PCM composite layer) to replace the liquid-liquid interface to separate the low-temperature heat storage medium and the high-temperature heat storage medium (such as cold and hot molten salt), thereby achieving efficient physical isolation between the cold and hot molten salt. The temperature-regulating layer is stably "pinned" in the solid composite layer and cannot be damaged by fluid disturbance or is damaged to a small extent by fluid disturbance. The thermal layer is stable, and the system efficiency does not decrease or decreases only slightly.

[0023] 5. This invention utilizes an optimized design with high porosity and large pore size on the low-temperature thermal storage medium (such as cold molten salt) side and low porosity and small pore size on the high-temperature thermal storage medium (such as hot molten salt) side in the temperature rise regulating functional layer. This allows the energy of the high-temperature thermal storage medium to be effectively recovered and utilized by the PCM, thereby enabling the low-temperature thermal storage medium to efficiently absorb the latent heat released by the PCM. Furthermore, since the temperature of the solid-state temperature rise regulating functional layer is always higher than that of the low-temperature thermal storage medium, the temperature of the low-temperature zone (such as the cold salt zone) can be maintained above the freezing point of the thermal storage medium (such as molten salt) for a long time. This eliminates the need for or requires only minimal backup heat tracing, significantly reducing reliance on high-energy-consuming and low-reliability electric heat tracing systems, thereby effectively reducing system operating energy consumption and improving system reliability.

[0024] 6. This utility model combines sensible heat storage of a single-tank heat storage medium (such as molten salt) with latent heat storage of phase change heat. It retains the advantage of fast response of sensible heat storage while compensating for the low energy density of single sensible heat storage through latent heat storage. Furthermore, by utilizing the synergistic advantages of the dual heat storage mechanism, it further achieves an integrated design of heat storage and release functions. This simplifies system piping connections and control logic (eliminating the need for complex medium switching processes), making overall control simpler. It also reduces the number of core equipment such as tanks and pipelines, directly lowering the system's investment cost. Compared to pure phase change heat storage systems, which rely heavily on phase change materials and require highly customized equipment, this utility model has a significantly lower investment cost. Moreover, due to the dual... The combination of heat storage mechanisms also endows the system with a high heat storage temperature, enabling it to provide medium and low temperature heat for building heating and high temperature steam for industrial production. This solves the problem that traditional single-tank systems are difficult to adapt to the heating needs of multiple scenarios due to their single heat storage temperature. Furthermore, since the latent heat storage of phase change significantly improves the heat storage capacity per unit volume, this invention does not need to rely on expanding the tank volume to meet the heat storage needs under the same heat storage capacity. Compared with the traditional single-tank thermocline system that relies solely on the sensible heat storage of molten salt and requires a larger volume to accommodate sufficient medium, this energy storage device is more compact and has a significantly higher energy density per unit volume. This saves space and reduces the space costs of system installation and maintenance.

[0025] 7. This invention utilizes a floating adjustment ring to achieve a floating design for the temperature jump adjustment functional layer. This allows the system to dynamically adjust the position of the temperature jump adjustment functional layer based on real-time monitoring of the demand for high-temperature thermal storage media (such as hot molten salt) and the return flow rate of low-temperature thermal storage media (such as cold molten salt). Stepless adjustment can be achieved between the maximum capacity of the high-temperature thermal storage media (such as hot molten salt) and the maximum capacity of the low-temperature thermal storage media (such as cold molten salt), ensuring the system is always adjusted to the optimal operating point under the current load, thereby maximizing energy utilization. Attached Figure Description

[0026] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 A cross-sectional structural schematic diagram of a phase change buffer energy storage device provided for an embodiment of this utility model; Figure 2 A schematic diagram of a small-hole ceramic skeleton provided for an embodiment of this utility model; Figure 3 This is a schematic diagram of a macroporous ceramic skeleton provided for an embodiment of the present invention.

[0027] In the picture: 1. High-temperature thermal storage medium circulation pump; 2. Top cover; 3. High-temperature zone flow equalizer; 4. High-temperature zone; 5. High-temperature thermal storage medium outlet; 6. Inner wall layer; 7. Small-hole composite layer; 8. Baffle; 9. Floating regulating ring; 10. Large-hole composite layer; 11. Outer wall layer; 12. Low-temperature thermal storage medium circulation pump; 13. Low-temperature zone; 14. Electric heater; 15. Insulation layer; 16. Low-temperature zone flow equalizer; 17. Low-temperature thermal storage medium outlet; 18. Tank body; 19. Base. Detailed Implementation

[0028] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0029] It should be noted that in this utility model, hot salt, hot molten salt, and high-temperature molten salt are the same substance, and cold salt, cold molten salt, and low-temperature molten salt are the same substance.

[0030] First embodiment: Please see Figures 1-3 This embodiment provides a phase change buffer energy storage device, including a device body. The device body includes a top cover 2, a tank 18, and a base 19 arranged sequentially from top to bottom. The tank 18 is provided with an inner wall layer 6, an outer wall layer 11, and an insulation layer 15 arranged sequentially from the inside to the outside. The inner wall layer 6 is provided at the position corresponding to the high temperature zone 4 of the tank 18, or the entire tank 18 is provided with an inner wall layer 6. The tank 18 is provided with a high temperature zone 4, a temperature jump regulation functional layer, and a low temperature zone 13 arranged sequentially from top to bottom. The high temperature zone 4 stores a high temperature heat storage medium, and the low temperature zone 13 stores a high temperature heat storage medium. The low-temperature thermal storage medium, with a temperature rise regulation functional layer comprising, from top to bottom, a small-pore composite layer 7, a partition 8, and a large-pore composite layer 10. The small-pore composite layer 7 includes a small-pore skeleton and a first phase change material for filling the small-pore skeleton. The large-pore composite layer 10 includes a large-pore skeleton and a second phase change material for filling the large-pore skeleton. The first phase change material and the second phase change material may be the same or different. The pore size of the small-pore composite layer 7 is smaller than that of the large-pore composite layer 10, and the pore size of the partition 8 is smaller than that of the small-pore composite layer 7. The low-temperature zone 13 is also provided with at least one electric heater 14. The high-temperature thermal storage medium input end is located on the top cover 2, and the high-temperature thermal storage medium outlet 5 is located at the end of the high-temperature zone 4 near the temperature jump adjustment functional layer; the low-temperature thermal storage medium input end is located at the end of the low-temperature zone 13 near the temperature jump adjustment functional layer, and the low-temperature thermal storage medium outlet 17 is located at the end of the low-temperature zone 13 near the base 19. A high-temperature thermal storage medium circulation pump 1 is also installed on the pipeline connected to the high-temperature thermal storage medium outlet 5, and a low-temperature thermal storage medium circulation pump 12 is also installed on the pipeline connected to the low-temperature thermal storage medium outlet 17. The volume of high-temperature zone 4 accounts for 20%-30% of the total volume of the device body, the volume of temperature rise regulating functional layer accounts for 40%-50% of the total volume of the device body, and the volume of low-temperature zone 13 accounts for 25%-35% of the total volume of the device body; the thickness of small-hole composite layer 7 accounts for 25% of the total thickness of temperature rise regulating functional layer, the thickness of partition 8 accounts for 5% of the total thickness of temperature rise regulating functional layer, and the thickness of large-hole composite layer 10 accounts for 70% of the total thickness of temperature rise regulating functional layer; The pore size of the small-pore composite layer 7 is 10-500μm, the pore size of the large-pore composite layer 10 is 5-100mm, and the pore size of the partition 8 is 1-5μm. The porosity of the small-pore composite layer 7 is 30-40%, and the porosity of the large-pore composite layer 10 is 70%-80%. Preferably, the heat storage medium can be molten salt, the small-pore composite layer 7 can be a small-pore ceramic-phase change material composite layer, the large-pore composite layer 10 can be a large-pore ceramic-phase change material composite layer, and the partition 8 can be a ceramic transition layer.

[0031] In a practical application scenario, the thermal storage medium is molten salt. The small-pore composite layer 7 is a small-pore ceramic-phase change material composite layer, the large-pore composite layer 10 is a large-pore ceramic-phase change material composite layer, and the partition 8 is a ceramic transition layer. In this case, the high-temperature thermal storage medium circulation pump 1 is a hot salt circulation pump, the high-temperature zone flow equalizer 3 is a hot salt flow equalizer, the high-temperature zone 4 is a hot salt zone, and the high-temperature thermal storage medium outlet is a hot salt outlet. The low-temperature thermal storage medium circulation pump 12 is a cold salt circulation pump, the low-temperature zone 13 is a cold salt zone, the low-temperature zone flow equalizer 16 is a cold salt flow equalizer, and the low-temperature thermal storage medium outlet 17 is a cold salt outlet. The specific design of each structure is as follows: The hot salt circulation pump is used to pump out the high-temperature molten salt in tank 18 and deliver it to the energy consumption end, such as power generation system, heating system, etc. The top cover 2 is used to seal the tank body 18, and has the necessary openings for pipe, manhole and instrument access; The hot salt flow equalizer is located at the top of the hot salt zone, which ensures that the newly injected high-temperature molten salt flows in evenly and avoids a violent impact on the flow field inside the tank 18. The hot salt zone has a lower density, so it is located at the top of tank 18 and is used to store high-temperature molten salt. Under normal circumstances, the temperature of high-temperature molten salt is about 560°C. The hot salt outlet is connected to the hot salt circulation pump, forming a channel for the high-temperature molten salt to leave the tank 18; The inner wall layer 6 is made of an alloy material that is resistant to high temperature and molten salt corrosion, such as optional Inconel 625 or 316H stainless steel. To reduce costs, the inner wall layer 6 can be positioned only in relation to the hot salt zone. In this case, it is essentially used to encapsulate the hot salt, achieve physical isolation of the hot salt, and prevent leakage caused by the corrosiveness of the hot salt to the metal. The microporous ceramic-phase change material composite layer consists of porous ceramics with low porosity and small pore size, and PCM impregnated with high phase change temperature. The porous ceramics can be, for example, SiC or Al2O3; the PCM can be, for example, customized eutectic salts such as Na2CO3-Li2CO3, NaCl-MgCl2, NaCl-CaCl2-MgCl2, or LiNO3-KCl. Its core function is efficient thermal conductivity. The pore size is 10μm-500μm, which falls within the micrometer range and generates extremely strong capillary forces, firmly locking the PCM within the pores and preventing leakage or migration. The low porosity, at 30-40%, means a higher ceramic skeleton density, thus forming continuous high thermal conductivity pathways and maximizing its effective thermal conductivity. The core task of this region is to "speed up" the process, rapidly introducing heat from the hot salt to ensure a high ceramic content, high effective thermal conductivity, and rapid heat transfer. The ceramic transition layer is a functionally graded region with a pore size of 1-5 μm. In principle, the pore size is smaller than that of the small-pore layer to prevent the movement of PCM material in the small-pore ceramic layer. The thickness is kept as small as possible to achieve a smooth transition of thermal stress and optimized distribution of heat flow. The macroporous ceramic-phase change material composite layer is composed of porous ceramic impregnated PCM with high porosity and large pore size. Its core functions are massive heat storage and efficient convective heat transfer. The pore size of the macroporous ceramic-PCM composite layer is 5-100 mm, which is within the millimeter range and greatly reduces the resistance to fluid flow. The high porosity of 70%-80% means that it can accommodate the largest amount of PCM, thereby maximizing the latent heat storage capacity. At the same time, the large pore size allows cold molten salt to penetrate and flow more deeply, significantly enhancing the convective heat transfer effect and ensuring that a high PCM ratio, high latent heat capacity, large pore size, strong convective heat transfer, and efficient heat release can be achieved. The outer wall layer 11 is made of carbon steel or low alloy steel and is the main structure that bears the overall pressure of the tank body 18. The cold salt circulation pump is used to pump out the molten salt from the cold salt zone and deliver it to the solar collector or heat exchanger for heating. The cold salt zone has a higher density and is located at the bottom of tank 18. It is used to store low-temperature molten salt, which is usually around 290°C. The electric heater 14 serves as an emergency backup system and is only activated under extreme conditions, such as after a long period of inactivity, to provide auxiliary heating for the cold salt zone and prevent the molten salt from solidifying. During normal operation, it relies on the temperature rise regulation function layer for heating and does not require activation. The insulation layer 15 is a high-performance insulation material wrapped around the entire tank body 18, such as optional nano aerogel, insulation cotton or rock wool, which greatly reduces the heat loss of the tank body 18 to the environment. The cold salt flow equalizer is located at the bottom of the cold salt zone, which ensures that the returned or pumped cold salt flows evenly and maintains stable thermal stratification. The cold salt outlet is connected to the cold salt circulation pump, forming a channel for the low-temperature molten salt to leave the tank 18; Tank 18 is the main body of the energy storage device; The base 19 is used to connect the tank 18 to the ground.

[0032] In this practical application scenario, the specific working process of the energy storage device is as follows: 1. Charging process (energy input): High-temperature molten salt from the solar collector or heat exchanger enters the hot salt zone of tank 18 from the top through pipes; the heat from the high-temperature molten salt is rapidly conducted to the microporous ceramic-PCM composite layer. Utilizing the low porosity and high thermal conductivity of this region, it can quickly absorb heat, causing the PCM inside to undergo a solid-liquid phase change, storing energy in the form of latent heat; subsequently, the heat continues to be transferred through the ceramic transition layer to the macroporous ceramic-PCM composite layer. Due to the high porosity structure of this region, it can accommodate a large amount of PCM, thus storing a large amount of latent heat; afterwards, some of the heat is released from the macroporous ceramic-PCM composite layer to the cold salt zone, continuously and gently heating the low-temperature molten salt therein, keeping its temperature always above the freezing point, achieving "active anti-freezing".

[0033] 2. Discharge Process (Energy Output): When the energy-consuming end requires electricity or heat, the hot salt circulation pump starts, pumping the high-temperature molten salt from the hot salt zone through the hot salt outlet to the power generation system or heating system. The molten salt that has released heat in the power generation system or heating system cools to approximately 290°C, becoming "cold salt." This cold salt returns to the cold salt zone inside tank 18 through pipes. The returning cold salt immediately comes into contact with the macroporous ceramic-PCM composite layer. Based on the large pore size and high surface area structure of this region, the convective heat transfer efficiency between the cold salt and the macroporous ceramic-PCM composite layer can be greatly enhanced. The cold salt absorbs heat from the macroporous ceramic-PCM composite layer, causing the PCM to undergo a liquid-solid phase change and release the stored latent heat. This process effectively increases the temperature of the cold salt, completely avoiding the risk of solidification. The heat from the small-pore ceramic-PCM composite layer then replenishes the cold side, forming a stable radial heat flow.

[0034] 3. Idle / Insulation Process: During the idle period when the system is neither charged nor discharged, the core value of the temperature rise regulation function layer is realized. Its stored latent heat becomes a stable internal heat source, continuously and slowly releasing heat to the cold salt zone to compensate for the heat lost from the tank 18 to the environment through the insulation layer 15. Therefore, even after a long period of idleness, the cold salt can be kept above its freezing point without the need for a high-energy-consuming electric heating system. The electric heater 14 is only used as a final emergency protection measure.

[0035] In a specific hotel application scenario, the specific implementation method is as follows: Designed according to the heating requirements of a large hotel, considering heat loss and load fluctuations, solar salt is selected. The molten salt is heated by ultra-high temperature steam exceeding 600°C generated by a valley-coupled ultra-high temperature heat pump or by high-temperature steam recovered during daily operation. The generated high-temperature molten salt is injected into the hot salt zone from the top, and the heat is rapidly conducted to the microporous silicon carbide-PCM layer. This PCM layer is filled with Na2CO3-Li2CO3, with a phase transition point of 500°C, and melts rapidly upon heating, storing a large amount of latent heat. The heat is then transferred through a ceramic transition layer to the macroporous alumina-PCM layer, where the PCM is filled with LiNO3-KCl, with a phase transition point of 283°C, and melts upon heating. During this process, the molten salt in the cold salt zone is... Continuous heating maintains a stable temperature above 300°C. A hot salt circulation pump pumps hot salt at approximately 550°C from the hot salt outlet to the power generation or heating system. Cold salt at approximately 290°C, returning after power generation or heating, enters the cold salt zone and immediately comes into contact with the macroporous alumina-PCM layer, whose temperature is still above its freezing point, and absorbs heat. The PCM solidifies and releases heat, ensuring that the cold salt temperature is always maintained within a safe range. When the system is idle during off-peak hours, the PCM in the macroporous alumina-PCM layer solidifies slowly, and the latent heat released is sufficient to compensate for the heat dissipation of the tank 18, maintaining the cold salt temperature at approximately 295°C. The electric heater 14 can be activated to heat the cold salt in extreme cases where the ambient temperature is extremely low and the system is shut down for a long time, preventing solidification.

[0036] Second Embodiment Unlike the first embodiment, the phase change buffer energy storage device provided in this embodiment also includes a floating adjustment ring 9, which is slidably connected to the inner wall of the tank 18, and the temperature rise adjustment function layer is disposed inside the floating adjustment ring 9; at this time, the entire tank 18 is provided with an inner wall layer 6.

[0037] The floating regulating ring 9 allows the system to dynamically adjust the position of the temperature surge regulating functional layer based on the real-time monitored hot salt demand and cold salt return flow. This enables the system to achieve stepless adjustment between the maximum hot salt capacity and the maximum cold salt capacity, thus optimizing its ability to cope with extreme load fluctuations. It should be noted that the temperature surge regulating functional layer itself is a robust and sealed whole, with no risk of hot salt mixing with cold salt or leakage.

[0038] At this point, the specific working process of the energy storage device is as follows: 1. Charging process (energy input): High-temperature molten salt from the solar collector or heat exchanger enters the hot salt zone of tank 18 from the top through pipes; the heat from the high-temperature molten salt is rapidly conducted to the microporous ceramic-PCM composite layer. Utilizing the low porosity and high thermal conductivity of this region, it can quickly absorb heat, causing the PCM inside to undergo a solid-liquid phase change, storing energy in the form of latent heat; subsequently, the heat continues to be transferred through the ceramic transition layer to the macroporous ceramic-PCM composite layer. Due to the high porosity structure of this region, it can accommodate a large amount of PCM, thus storing a large amount of latent heat; afterwards, some of the heat is released from the macroporous ceramic-PCM composite layer to the cold salt zone, continuously and gently heating the low-temperature molten salt therein, keeping its temperature always above the freezing point, achieving "active anti-freezing".

[0039] 2. Discharge Process (Energy Output): When the energy-consuming end requires electricity or heat, the hot salt circulation pump starts, pumping the high-temperature molten salt from the hot salt zone through the hot salt outlet to the power generation system or heating system. The molten salt that has released heat in the power generation system or heating system cools to approximately 290°C, becoming "cold salt." This cold salt returns to the cold salt zone inside tank 18 through pipes. The returning cold salt immediately comes into contact with the macroporous ceramic-PCM composite layer. Based on the large pore size and high surface area structure of this region, the convective heat transfer efficiency between the cold salt and the macroporous ceramic-PCM composite layer can be greatly enhanced. The cold salt absorbs heat from the macroporous ceramic-PCM composite layer, causing the PCM to undergo a liquid-solid phase change and release the stored latent heat. This process effectively increases the temperature of the cold salt, completely avoiding the risk of solidification. The heat from the small-pore ceramic-PCM composite layer then replenishes the cold side, forming a stable radial heat flow.

[0040] 3. Idle / Insulation Process: During the idle period when the system is neither charged nor discharged, the core value of the temperature rise regulation function layer is realized. Its stored latent heat becomes a stable internal heat source, continuously and slowly releasing heat to the cold salt zone to compensate for the heat lost from the tank 18 to the environment through the insulation layer 15. Therefore, even after a long period of idleness, the cold salt can be kept above its freezing point without the need for a high-energy-consuming electric heating system. The electric heater 14 is only used as a final emergency protection measure.

[0041] 4. Temperature Jump Regulation Function Layer Adjustment Process: When the system starts up, the temperature jump regulation function layer is located in a preset middle position, which is the initialization position. When in charging mode, a large amount of high-temperature hot salt absorbs heat and enters tank 18. The system predicts that the demand for hot salt will increase significantly, so it drives the floating regulating ring 9 to move downward, that is, to move the temperature jump regulation function layer downward, maximizing the volume of the hot salt zone to store more high-grade heat energy. When in energy release mode, hot salt enters the heat exchange equipment, and after releasing energy, cold salt flows back. The system drives the floating regulating ring 9 to move upward, that is, to move the temperature jump regulation function layer upward, appropriately increasing the volume of the cold salt zone to provide a larger buffer capacity and ensure sufficient heat exchange area to prevent cold salt from solidifying. In low-load mode, the floating regulating ring 9 can be adjusted to a balanced position, so that the system is in the optimal efficiency range.

[0042] In a specific hotel application scenario, the implementation method is as follows: Designed according to the heating requirements of a large hotel, considering heat loss and load fluctuations, solar salt is selected. A high-temperature steam exceeding 600°C, generated by a valley-coupled ultra-high-temperature heat pump or high-temperature steam recovered during daily operation, is used to heat the molten salt. The generated high-temperature molten salt is injected from the top into the hot salt zone, and the heat is rapidly conducted to the microporous silicon carbide-PCM layer. This PCM layer is filled with Na2CO3-Li2CO3, with a phase transition point of 500°C, and melts rapidly upon heating, storing a large amount of latent heat. The heat is then transferred through a ceramic transition layer to the macroporous alumina-PCM layer, where the PCM is filled with LiNO3-KCl, with a phase transition point of 283°C, and melts upon heating. During this process, the molten salt in the cold salt zone is continuously heated, with the temperature stabilized above 300°C. The hot salt circulation pump... Hot salt at approximately 550°C is pumped from the hot salt outlet to the power generation or heating system; cold salt at approximately 290°C, returning after power generation or heating, enters the cold salt zone and immediately comes into contact with the macroporous alumina-PCM layer, whose temperature is still above its freezing point, and absorbs heat. The PCM solidifies and releases heat, ensuring that the cold salt temperature is always maintained within a safe range; when the heat / electricity demand is low and the system is idle, the PCM in the macroporous alumina-PCM layer solidifies slowly, and the latent heat released is sufficient to compensate for the heat dissipation of the tank 18, keeping the cold salt temperature at approximately 295°C; due to the low heat demand load, the floating regulating ring 9, i.e., the temperature jump regulating function layer, is maintained in a balanced position, keeping the system in the optimal efficiency range; the electric heater 14 can be activated to heat the cold salt in extreme cases where the ambient temperature is extremely low and the system is shut down for a long time, preventing solidification.

[0043] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this utility model. Unless otherwise specified, the embodiments and features of this utility model can be arbitrarily combined with each other.

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