A phase change energy storage hot water circulation storage system and control method

Abstract

The application discloses a phase change energy storage hot water circulation storage system, which comprises a heat storage box body with a heat preservation structure, a composite phase change heat storage module arranged in the heat storage box body, the composite phase change heat storage module comprising a phase change material base body and a three-dimensional heat conduction network reinforcing structure embedded in the phase change material base body, an inner built-in reinforced heat exchanger immersed in the composite phase change heat storage module, the inner built-in reinforced heat exchanger comprising a heat exchange main pipe and fins fixedly connected to the outer wall of the heat exchange main pipe, a temperature sensor group comprising at least a first temperature sensor arranged on a water inlet pipe, a second temperature sensor arranged on a water outlet pipe and a module temperature sensor arranged in the composite phase change heat storage module, and an intelligent controller. Compared with the prior art, the phase change energy storage hot water circulation storage system adopts the composite phase change material of the phase change material base body, the porous heat conduction framework and the nano heat conduction additive, so that the defects of low heat conductivity and slow response speed of the phase change material in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of thermal energy storage and utilization, specifically to a phase change energy storage hot water circulation storage system and control method. Background Technology

[0002] With the global energy structure transformation and the advancement of "dual carbon" goals, efficient thermal energy storage technology has become key to solving the spatial and temporal mismatch between energy supply and demand. Hot water supply is a rigid demand, and its traditional storage methods mainly rely on the sensible heat storage of water.

[0003] Centralized hot water storage tanks utilize the sensible heat of water for heat storage, but their heat storage capacity per unit volume is limited. To meet long-term, large-capacity heating demands, enormous tanks must be constructed, which not only increases building costs but also makes them difficult to promote and apply in space-constrained locations such as high-rise apartments and distributed energy stations.

[0004] During thermal storage, energy loss is unavoidable due to thermal bridging and surface heat dissipation. More importantly, traditional water tanks rely on the natural stratification of hot water to achieve effective heat extraction. However, during frequent water extraction and replenishment, the mixing of hot and cold water quickly disrupts this stratification, leading to a sharp reduction in available thermal energy and a significant decrease in system efficiency.

[0005] Although phase change energy storage technology has been introduced to improve energy density, commonly used phase change materials (such as paraffin) have extremely low thermal conductivity (typically 0.1-0.3 W / (m·K)). This results in slow heat transfer during the charging (heat absorption and melting of the phase change material) and releasing (heat release during solidification) processes, leading to a severe lag in system response and an inability to quickly meet the hot water demand during peak periods.

[0006] Phase change materials (PCMs) exhibit volume changes and fluidity during solid-liquid phase transitions. Poor encapsulation techniques can easily lead to leakage, contaminating water or damaging equipment. Furthermore, prolonged thermal cycling can cause phase separation and performance degradation, affecting the long-term reliability of the system. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing hot water energy storage devices, such as large size, low energy density, stratification of hot and cold water mixing leading to a sharp reduction in available thermal energy, significant decrease in system efficiency, poor thermal conductivity, and slow response speed. To overcome these deficiencies, this invention proposes a phase change energy storage hot water circulation system and control method. To achieve the above objectives, the present invention adopts the following technical solution: A phase change energy storage hot water circulation system includes: The thermal storage box has an insulated structure; The composite phase change thermal storage module is set inside the thermal storage box. The composite phase change thermal storage module includes a phase change material matrix and a three-dimensional thermally conductive network reinforcement structure embedded in the phase change material matrix. An integrated enhanced heat exchanger is immersed inside the composite phase change thermal storage module. The integrated enhanced heat exchanger includes a heat exchange main tube and fins fixedly connected to the outer wall of the heat exchange main tube. A solenoid valve is installed at the water inlet end of each heat exchange main tube. The water inlets of all heat exchange main tubes are connected through a main water inlet pipe, and the water outlets are connected through a main water outlet pipe. The hot water circulation pipeline includes an inlet pipe, an outlet pipe, and a circulation pump. The inlet pipe and the outlet pipe are respectively connected to the inlet main pipe and the outlet main pipe of the built-in enhanced heat exchanger. The circulation pump is used to drive the fluid to flow in the hot water circulation pipeline and the built-in enhanced heat exchanger. The temperature sensor group includes at least a first temperature sensor installed on the inlet pipe, a second temperature sensor installed on the outlet pipe, and a module temperature sensor installed inside the composite phase change thermal energy storage module. The intelligent controller is electrically connected to the temperature sensor group, the circulating pump, and the solenoid valve. The intelligent controller controls the start, stop, or speed of the circulating pump and the solenoid valve based on the detection signals from the temperature sensor group.

[0008] As a further preferred embodiment of the present invention, the composite phase change thermal storage module adopts a tiered packaging structure, the tiered packaging structure comprising: First-level encapsulation: consists of microcapsules encapsulating a phase change material matrix and a three-dimensional thermally conductive network reinforcement structure; Second-level encapsulation: Composed of open-cell porous foam material filled with microcapsules; The third level of encapsulation consists of a heat storage unit formed by molding open-cell porous foam material.

[0009] As a further preferred embodiment of the present invention, the surface of the fins is coated with a hydrophilic or oleophilic modified layer.

[0010] As a further preferred embodiment of the present invention, the three-dimensional thermally conductive network enhancement structure includes a porous thermally conductive framework and nano-thermal conductive additives dispersed in the pores of the porous thermally conductive framework; the porous thermally conductive framework is expanded graphite, and the nano-thermal conductive additives are copper nanowires or carbon nanotubes.

[0011] As a further preferred embodiment of the present invention, the fins are corrugated fins, which extend radially outward along the heat exchange main pipe, and the ends of the fins extend to near the outer edge of the composite phase change thermal storage module.

[0012] As a further preferred embodiment of the present invention, the temperature sensor group includes an upper temperature sensor, a middle temperature sensor, and a lower temperature sensor distributed along the height direction of the composite phase change thermal storage module, forming a temperature sensor array.

[0013] As a further preferred embodiment of the present invention, the thermal insulation structure of the thermal storage box includes an inner liner and an outer shell, as well as a vacuum insulation layer or high-performance foamed insulation material filled between the inner liner and the outer shell.

[0014] A control method for a phase change energy storage hot water circulation system includes: In the heat charging mode, when the external heat source has surplus heat energy and the temperature of the composite phase change heat storage module has not reached the heat charging set value, the intelligent controller controls the circulation pump to start, so that the high-temperature hot water from the external heat source flows through the built-in enhanced heat exchanger. The heat is transferred to the composite phase change heat storage module through the heat exchange main tube and fins, so that the phase change material matrix absorbs heat, melts and stores latent heat. In the heat release mode, when a demand for hot water is detected at the water end or the temperature of the second temperature sensor is lower than the heat release set value, the intelligent controller controls the circulation pump to start, so that the low temperature water flows through the built-in enhanced heat exchanger to absorb the latent heat released by the solidification of the phase change material matrix in the composite phase change heat storage module. The heated water is then supplied to the water end through the outlet pipe.

[0015] As a further preferred embodiment of the present invention, in the heat release mode, the intelligent controller prioritizes the use of heat from the high-temperature region at the top of the composite phase change thermal storage module based on the temperature signal detected by the temperature sensor array distributed along the height direction of the composite phase change thermal storage module, thereby achieving gradient heat extraction.

[0016] The phase change energy storage hot water circulation storage system and control method proposed in this invention have the following advantages compared with the prior art. 1. This invention overcomes the shortcomings of low thermal conductivity and slow response speed of existing phase change materials by employing a composite phase change material matrix, a porous thermally conductive framework, and nano-thermal conductive additives. Expanded graphite forms a continuous thermally conductive framework, and copper nanowires further bridge the gaps in the framework, forming a synergistic thermally conductive network. This technique significantly increases the thermal conductivity of the composite material from 0.2 W / (m·K) of pure paraffin to over 2.5 W / (m·K), thereby greatly accelerating the charging and discharging process and achieving rapid response. 2. This invention completely solves the problems of easy leakage and poor cycle stability of phase change materials in existing technologies through a tiered encapsulation structure of microcapsules, porous foam, and molding. Microcapsules serve as the first-level encapsulation to prevent liquid leakage; open-cell polyurethane foam serves as the second-level encapsulation to provide buffer space to accommodate volume changes; and overall molding ensures structural integrity. This technology results in a heat storage efficiency decay of only 3.5% after 365 cycles (example data), far superior to the 15% decay of ordinary phase change heat storage boxes, ensuring long-term sealing and reliability. 3. This invention solves the problems of high contact thermal resistance and low heat exchange efficiency between heat exchangers and phase change materials in the prior art by setting a heat exchanger with radially corrugated fins and a hydrophilic / oleophilic modified layer on its surface. The large-diameter fins significantly increase the heat exchange area; the surface modified layer reduces the contact angle between the liquid phase change material and the metal, enhancing wettability and avoiding the "dry burning" phenomenon. This technology allows the invention to complete heat charging within 70 minutes, while ordinary phase change heat storage boxes require 150 minutes, increasing the charging rate by more than double. 4. This invention solves the defects of large heat loss and easy damage to temperature stratification in the prior art by organically combining a vacuum insulation layer, a temperature sensor array, and an intelligent control strategy. The vacuum insulation layer controls the daily heat loss rate to below 1%; the layered temperature sensor array combined with the intelligent controller realizes on-demand heat extraction and gradient heat extraction, giving priority to the use of high-temperature heat energy at the top, avoiding indiscriminate mixing of hot and cold water, and significantly improving the effective heat energy utilization rate (the total heat storage capacity is increased by 16.7% compared with traditional water tanks while the volume is smaller). Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a schematic diagram of the thermal storage unit. Figure 3 This is a schematic diagram of the heat charging mode process involved in the present invention. Figure 4 This is a schematic diagram of the exothermic mode process involved in the present invention.

[0018] The meanings of the reference numerals in the figure are as follows: 100, heat storage box; 101, inner liner; 102, outer shell; 103, insulation material; 200, heat storage unit; 201, microcapsule; 202, phase change material matrix; 203, reinforcing structure; 204, foam material; 300, built-in enhanced heat exchanger; 301, heat exchange main pipe; 302, fins; 303, solenoid valve; 401, water inlet pipe; 402, water outlet pipe; 403, circulating pump; 501, first temperature sensor; 502, second temperature sensor; 503, sensor array; 600, intelligent controller. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] The present invention relates to a phase change energy storage hot water circulation storage system and control method applicable to scenarios such as solar thermal utilization, industrial waste heat recovery, heat pump heat storage, and building heating and domestic hot water supply. Example 1: A phase change energy storage hot water circulation system, comprising: The heat storage box 100 has an insulation structure. The insulation structure of the heat storage box 100 includes an inner liner 101 and an outer shell 102, as well as a vacuum insulation layer or high-performance foamed insulation material 103 filled between the inner liner 101 and the outer shell 102.

[0021] A composite phase change thermal energy storage module is disposed inside the thermal energy storage box 100. The composite phase change thermal energy storage module includes a phase change material matrix 202 and a three-dimensional thermally conductive network reinforcement structure 203 embedded in the phase change material matrix 202. The composite phase change thermal energy storage module adopts a tiered packaging structure, which includes: The first-level encapsulation consists of microcapsules 201 that encapsulate a phase change material matrix 202 and a three-dimensional thermally conductive network reinforcement structure 203. The three-dimensional thermally conductive network reinforcement structure 203 includes a porous thermally conductive framework and nano-thermal conductive additives dispersed in the pores of the porous thermally conductive framework. The porous thermally conductive framework is expanded graphite, and the nano-thermal conductive additives are copper nanowires or carbon nanotubes.

[0022] Second-level encapsulation: Composed of open-cell porous foam material 204 filled with microcapsules 201; The third level of encapsulation consists of a heat storage unit 200 formed by molding open-cell porous foam material 204.

[0023] An integrated enhanced heat exchanger 300 is immersed inside the composite phase change thermal storage module. The integrated enhanced heat exchanger 300 includes a heat exchange main pipe 301 and fins 302 fixedly connected to the outer wall of the heat exchange main pipe 301. The surface of the fins 302 is coated with a hydrophilic or oleophilic modified layer. The fins 302 are corrugated fins 302, which extend radially outward along the heat exchange main pipe 301, and the ends of the fins 302 extend to near the outer edge of the composite phase change thermal storage module. A solenoid valve 303 is installed at the water inlet end of each heat exchange main pipe 301. The water inlets of all heat exchange main pipes 301 are connected through a main water inlet pipe, and the water outlets are connected through a main water outlet pipe.

[0024] The hot water circulation pipeline includes an inlet pipe 401, an outlet pipe 402, and a circulation pump 403. The inlet pipe 401 and the outlet pipe 402 are respectively connected to the inlet main pipe and the outlet main pipe of the built-in enhanced heat exchanger 300. The circulation pump 403 is used to drive the fluid to flow in the hot water circulation pipeline and the built-in enhanced heat exchanger 300.

[0025] The temperature sensor group includes at least a first temperature sensor 501 disposed on the water inlet pipe 401, a second temperature sensor 502 disposed on the water outlet pipe 402, and a module temperature sensor disposed inside the composite phase change thermal storage module; the temperature sensor group includes an upper layer temperature sensor, a middle layer temperature sensor and a lower layer temperature sensor distributed along the height direction of the composite phase change thermal storage module, forming a temperature sensor array 503.

[0026] The intelligent controller 600 is electrically connected to the temperature sensor group, the circulating pump 403 and the solenoid valve 303. The intelligent controller 600 controls the start, stop or speed of the circulating pump 403 and the solenoid valve 303 according to the detection signal of the temperature sensor group.

[0027] Example 2: A control method for a phase change energy storage hot water circulation system, comprising: In the heat charging mode, when the external heat source has surplus heat energy and the temperature of the composite phase change heat storage module has not reached the heat charging set value, the intelligent controller controls the circulation pump to start, so that the high-temperature hot water from the external heat source flows through the built-in enhanced heat exchanger. The heat is transferred to the composite phase change heat storage module through the heat exchange main tube and fins, so that the phase change material matrix absorbs heat, melts and stores latent heat. In the heat release mode, when a demand for hot water is detected at the water end or the temperature of the second temperature sensor is lower than the heat release set value, the intelligent controller controls the circulation pump to start, so that the low temperature water flows through the built-in enhanced heat exchanger to absorb the latent heat released by the solidification of the phase change material matrix in the composite phase change heat storage module. The heated water is then supplied to the water end through the outlet pipe.

[0028] In the heat release mode, the intelligent controller prioritizes the use of heat from the high-temperature region at the top of the composite phase change thermal storage module based on the temperature signals detected by the temperature sensor array distributed along the height of the module, thereby achieving gradient heat extraction.

[0029] Example 3: A phase change energy storage hot water circulation storage system is used as a solar-assisted heating system for a small office building.

[0030] Thermal storage chamber: Stainless steel inner liner and galvanized steel outer shell, with nanoporous silica aerogel filling the space between the two to form a vacuum insulation layer with a thermal conductivity of less than 0.005 W / (m・K) and an inner liner volume of 200L.

[0031] Composite phase change thermal energy storage module: Composed of shaped composite phase change material thermal energy storage units, tightly packed in the inner tank. (See Figure 2.)

[0032] The composite phase change thermal energy storage unit employs a tiered encapsulation method. The specific fabrication process includes: 1. Material preparation: Paraffin wax with a melting point of 60℃ and a latent heat of 180 kJ / kg was used as the matrix; 5% by mass of expanded graphite and 2% by mass of copper nanowires were added and mixed evenly.

[0033] 2. First-stage encapsulation: The above mixture is encapsulated in a melamine resin shell by in-situ polymerization to form microcapsules with a diameter of 1-5 mm; 3. Second-stage encapsulation: Microcapsules are filled into the pores of open-cell polyurethane foam.

[0034] 4. Third-stage encapsulation: The foam blocks filled above are molded into standard "brick"-shaped thermal storage units.

[0035] Built-in enhanced heat exchanger: vertically installed in the center of the heat storage module.

[0036] The built-in enhanced heat exchanger consists of a 25mm outer diameter 316L stainless steel heat exchange main tube and multiple radially extending corrugated fins. The fins have an outer diameter of 180mm, a spacing of 20mm, and are coated with an oleophilic modified layer. The heat storage units are tightly packed around the heat exchanger, with a 5-10mm expansion gap between them and the inner wall.

[0037] Hot water circulation pipeline: including circulation pump, three-way valve, inlet pipe, and outlet pipe.

[0038] Temperature sensor group: including the first sensor at the inlet, the second sensor at the outlet, and the third sensor array distributed in the upper, middle and lower layers of the thermal storage module.

[0039] Intelligent controller: Connects all sensors, circulation pumps, and heat source control terminals.

[0040] Combination Figure 3 In the charging mode, when the outlet water temperature of the solar collector reaches 85℃, the intelligent controller starts the circulation pump. The 85℃ hot water enters the heat exchange main pipe through the inlet pipe, and the heat is rapidly conducted to the surrounding heat storage units through the main pipe wall and fins. Under the action of the thermally conductive network composed of expanded graphite and copper nanowires, the paraffin wax quickly absorbs latent heat and melts. The cooled water (approximately 65℃) flows back through the outlet pipe. After 70 minutes, the temperature distribution throughout the entire heat storage module is uniform, completing the charging process.

[0041] Combination Figure 4 In heat release mode, when the outlet water temperature of the solar collector reaches 85℃, the intelligent controller starts the circulation pump. In heat release mode 8, when water or heating demand is activated in the office building, and the controller detects that the outlet water temperature is lower than the set value (55℃), it starts the circulation pump. At room temperature tap water (approximately 15℃) enters the heat exchanger, absorbs the latent heat released by the solidification of liquid paraffin in the heat storage module, and is heated to approximately 60℃ before being supplied to the user. Based on temperature data from the third sensor array, the controller prioritizes the use of heat from the upper high-temperature area to achieve gradient heat extraction.

[0042] Example 4: To verify the technical effect of the phase change energy storage hot water circulation storage system and control method involved in this invention, the following comparative example is set up: Comparative Example 1 (Traditional Water Tank): 200L ordinary hot water storage tank, without phase change materials.

[0043] Comparative Example 2 (Ordinary Phase Change Chamber): Same volume, but filled with 150kg of pure paraffin (no expanded graphite, copper nanowires, no cascade encapsulation, no reinforcing fins).

[0044] Conduct a heat charging rate test: The conditions are: source inlet temperature 90℃, flow rate 20L / min.

[0045] The test results are as follows: Traditional water tank: the water temperature rises from 20℃ to 60℃ in 90 minutes; Ordinary phase change tank: the center temperature of the paraffin reaches 60℃ in 150 minutes; Embodiment of the present invention: the entire thermal storage module completes the phase change in 70 minutes.

[0046] The conclusion is that the embodiment of the present invention has the fastest heating rate, and the rate of response is improved compared with traditional water tanks.

[0047] Conduct effective thermal storage density and capacity tests: The heat storage capacity of a traditional water tank is approximately 33440 kJ, calculated as follows: 200kg × 4.18 kJ / (kg·K) × (60-20)K ≈ 33440 kJ.

[0048] In this embodiment of the invention: heat storage = latent heat (150kg × 180 kJ / kg = 27000 kJ) + sensible heat (150kg × 2.0 kJ / (kg·K) × 40K ≈ 12000 kJ) = 39000 kJ.

[0049] The conclusion is that, with a volume significantly smaller than that of a traditional water tank (the inner tank actually holds only about 50L of water, with the remaining space occupied by the heat storage unit), the total heat storage capacity is increased by about 16.7%.

[0050] Long-term cycling stability test: Conditions: Simulate a complete charge-discharge cycle once a day for 365 days.

[0051] Test results: Ordinary phase change chamber: obvious phase separation and leakage occurred, and the thermal storage efficiency decreased by 15%. Embodiment of this invention: cascaded encapsulation effectively prevents leakage, causes no structural damage, and the thermal storage efficiency decreases by only 3.5%.

[0052] In conclusion, the embodiments of the present invention show no structural damage, slow decline in thermal storage efficiency, and a significantly extended service life.

[0053] Comprehensive application scenario testing: During prolonged cloudy winter days (when solar energy is insufficient), the system uses solar heating to replenish heat during peak daytime electricity prices. During off-peak nighttime electricity prices and before the next morning's peak electricity demand, the system releases heat to supply the office building's heating and domestic hot water needs from 8:00 AM to 10:00 AM. Actual measurement results show that, relying on this system, the power consumption of heat pump-assisted heating is reduced by 62% compared to a system without energy storage, achieving significant peak shaving and valley filling benefits and economic operational efficiency.

[0054] Example 5: Alternative Solution. The phase change material matrix of this invention can be replaced with fatty acids (such as lauric acid), with a melting point controlled at 40-50°C, suitable for low-temperature floor radiant heating systems.

[0055] The porous thermally conductive framework can be made of copper foam or aluminum foam, and the nano-additives can be carbon nanotubes.

[0056] Melamine foam can be used as the foam material for tiered encapsulation.

[0057] The structure, connection relationship and control method of other components of the alternative scheme are basically the same as those of Embodiments 1 and 2, and will not be described again here.

[0058] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A phase change energy storage hot water circulation system, characterized in that, include: A thermal storage box, wherein the thermal storage box has a heat insulation structure; A composite phase change thermal storage module is disposed inside the thermal storage box. The composite phase change thermal storage module includes a phase change material matrix and a three-dimensional thermally conductive network reinforcement structure embedded in the phase change material matrix. An integrated enhanced heat exchanger is immersed in the interior of the composite phase change thermal storage module. The integrated enhanced heat exchanger includes a heat exchange main pipe and fins fixedly connected to the outer wall of the heat exchange main pipe. Each heat exchange main pipe is equipped with a solenoid valve at its inlet end. The inlets of all heat exchange main pipes are connected through a main inlet pipe, and the outlet ends are connected through a main outlet pipe. The hot water circulation pipeline includes an inlet pipe, an outlet pipe, and a circulation pump. The inlet pipe and the outlet pipe are respectively connected to the inlet main pipe and the outlet main pipe of the built-in enhanced heat exchanger. The circulation pump is used to drive the fluid to flow in the hot water circulation pipeline and the built-in enhanced heat exchanger. The temperature sensor group includes at least a first temperature sensor disposed on the inlet pipe, a second temperature sensor disposed on the outlet pipe, and a module temperature sensor disposed inside the composite phase change thermal energy storage module. The intelligent controller is electrically connected to the temperature sensor group, the circulating pump, and the solenoid valve. The intelligent controller controls the start / stop or speed of the circulating pump and the solenoid valve based on the detection signals from the temperature sensor group.

2. The phase change energy storage hot water circulation system according to claim 1, characterized in that, The composite phase change thermal energy storage module adopts a tiered packaging structure, which includes: First-level encapsulation: consisting of microcapsules encapsulating the phase change material matrix and the three-dimensional thermally conductive network reinforcement structure; Second-level encapsulation: Composed of an open-cell porous foam material filled with the microcapsules; The third level of encapsulation consists of a heat storage unit formed by molding the aforementioned open-cell porous foam material.

3. The phase change energy storage hot water circulation system according to claim 1, characterized in that, The surface of the fins is coated with a hydrophilic or oleophilic modified layer.

4. The phase change energy storage hot water circulation system according to claim 1, characterized in that, The three-dimensional thermally conductive network enhancement structure includes a porous thermally conductive framework and nano-thermal conductive additives dispersed in the pores of the porous thermally conductive framework; the porous thermally conductive framework is expanded graphite, and the nano-thermal conductive additives are copper nanowires or carbon nanotubes.

5. The phase change energy storage hot water circulation system according to claim 1, characterized in that, The fins are corrugated fins that extend radially outward along the heat exchange main pipe, with the ends of the fins extending close to the outer edge of the composite phase change thermal storage module.

6. The phase change energy storage hot water circulation system according to claim 1, characterized in that, The temperature sensor group includes an upper temperature sensor, a middle temperature sensor, and a lower temperature sensor distributed along the height direction of the composite phase change thermal storage module, forming a temperature sensor array.

7. The phase change energy storage hot water circulation system according to claim 1, characterized in that, The thermal insulation structure of the thermal storage box includes an inner liner and an outer shell, as well as a vacuum insulation layer or high-performance foamed insulation material filled between the inner liner and the outer shell.

8. A control method for a phase change energy storage hot water circulation storage system based on any one of claims 1 to 7, characterized in that, include: In the heat charging mode, when the external heat source has surplus heat energy and the temperature of the composite phase change heat storage module has not reached the heat charging set value, the intelligent controller controls the circulation pump to start, so that the high-temperature hot water from the external heat source flows through the built-in enhanced heat exchanger. The heat is transferred to the composite phase change heat storage module through the heat exchange main pipe and the fins, so that the phase change material matrix absorbs heat, melts and stores latent heat. In the heat release mode, when a demand for hot water is detected at the water end or the temperature of the second temperature sensor is lower than the heat release set value, the intelligent controller controls the circulation pump to start, so that the low temperature water flows through the built-in enhanced heat exchanger to absorb the latent heat released by the solidification of the phase change material matrix in the composite phase change heat storage module. The heated water is then supplied to the water end through the outlet pipe.

9. The control method according to claim 8, characterized in that, In the heat release mode, the intelligent controller prioritizes the use of heat from the high-temperature region at the top of the composite phase change thermal storage module based on the temperature signals detected by the temperature sensor array distributed along the height direction of the composite phase change thermal storage module, thereby achieving gradient heat extraction.

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