Equipment and method for testing heat storage performance of phase change heat storage refractory material

Abstract

The invention discloses equipment and a method for testing the heat storage performance of a phase change heat storage refractory material. The equipment comprises an atmosphere furnace, a calorimetric device, a circulating cooling heat exchange system and a computer control analysis system, the atmosphere furnace can realize multi-atmosphere control and heating in a wide temperature range of 0-1800 DEG C, the calorimetric device adapts to sample containers and net bags made of different materials according to test temperatures, the circulating cooling heat exchange system accurately controls the flow and temperature of cooling liquid, and the computer control analysis system realizes synchronous acquisition and calculation of multiple parameters. The testing method comprises the steps of sample preparation, heating, falling, heat transfer, parameter calculation and data verification, and the phase change temperature, sensible heat, latent heat, total heat storage amount and specific heat capacity can be measured synchronously. The invention solves the problems of narrow test range, low precision and incapability of representing the overall performance of the material in the prior art, has the advantages of simplicity in operation, wide test range, high precision, good safety and the like, and is suitable for testing adaptive heat storage materials of various specifications.

Description

A device and method for testing the heat storage performance of phase change heat storage refractory materials Technical Field

[0001] This invention relates to the field of evaluation technology of heat storage capacity of phase change heat storage refractory materials, and more specifically, to a test device and method for the heat storage performance of phase change heat storage refractory materials. Background Technology

[0002] Phase change thermal energy storage technology is a method that uses the absorption and release of energy during the phase change of phase change materials (PCMs) to store and release energy. It can effectively solve the mismatch between energy supply and demand in terms of time, location, and intensity, and make rational use of energy and reduce environmental pollution.

[0003] The heat storage density and specific heat capacity of phase change materials are the core parameters for evaluating their heat storage capacity. For phase change heat storage refractory materials, accurate measurement of their thermophysical parameters is crucial for practical application selection, system design and performance evaluation.

[0004] Currently, the main methods for testing the heat storage density and specific heat capacity of materials include differential scanning calorimetry (DSC) and calorimetry. DSC is only applicable to trace amounts of material up to 10 mg, and such small samples cannot represent the overall performance of phase change refractories, resulting in unrepresentative test results. Calorimetry uses copper as a calorimeter, calculating parameters by equating the heat absorbed by the calorimeter with the heat released by the sample; however, its temperature range is only 150℃ to 20℃, which is too low to meet the high-temperature testing requirements of refractory materials.

[0005] Chinese invention patent CN107389227A discloses a method for determining the residual heat storage capacity of phase change energy storage materials. This method, based on the principle of energy conservation, equates the heat released by the phase change energy storage material to the sum of the heat carried away by the heat exchange circulating water and the heat dissipated by the insulation box. However, the test does not consider that the power consumption during heating is absorbed not only by the phase change energy storage material but also by components inside the insulation box, leading to a large error in the heat storage capacity test and failing to specify the test temperature range. Chinese invention patent CN110174433A discloses a method for testing the heat storage capacity of phase change materials, calculating the heat storage capacity of the phase change material based on the heat received by the heat transfer medium and container. However, it does not specify how the sample after energy storage is placed in the heat transfer medium and does not consider heat loss during sample transfer, resulting in a large measurement error. Chinese invention patent with publication number CN105675647B discloses a phase change heat storage test method. It uses hot water as a heat source to heat the phase change material to calculate the heat storage. However, the temperature after heating the water does not exceed 100°C, which also cannot meet the high-temperature test requirements of refractory materials.

[0006] In addition, existing technologies also have problems with the poor adaptability of testing equipment to phase change heat storage refractory materials, lack of component material selection and atmosphere control mechanisms for high-temperature environments, and difficulty in simultaneously obtaining multi-dimensional thermophysical parameters such as phase change temperature, sensible heat, and latent heat. Furthermore, the validity of the data lacks reliable verification standards.

[0007] Therefore, there is an urgent need for a testing device and method that has a wide testing temperature range, high accuracy, can simultaneously measure multiple parameters, and is suitable for phase change heat storage refractory materials. Summary of the Invention

[0008] In view of this, the purpose of this invention is to provide a testing device and method for the heat storage performance of phase change heat storage refractory materials, so as to solve the technical problems of narrow testing temperature range, poor sample representativeness, large error, single parameter and insufficient adaptability of the prior art.

[0009] To achieve the above objectives, the first objective of this invention is to provide a testing device for the heat storage performance of phase change heat storage refractory materials, comprising an atmosphere furnace, a calorimeter, a circulating cooling heat exchange system, and a computer control and analysis system; the atmosphere furnace has a lower opening at the bottom of the furnace chamber, and a movable heat-insulating furnace cover is sealed and installed at the lower opening; the atmosphere furnace has a connecting pipe vertically embedded in the inner wall of the lower opening and an adjustable platform horizontally embedded in the side wall of the furnace chamber; the connecting pipe extends vertically upward to directly above the adjustable platform; the test sample is suitable for being placed on the upper surface of the adjustable platform and located at the inner top of the connecting pipe, and the test sample, the connecting pipe, and the... The vertical central axis of the adjustable stage coincides with the vertical axis of the calorimeter. The calorimeter includes an insulated box sealed to the bottom surface of the movable insulated furnace cover, a sample container suspended inside the insulated box, a mesh bag fixed to the bottom of the sample container, a temperature sensor assembly, and a pressure sensor connected to the mesh bag. The insulated box is filled with coolant. The temperature sensor assembly is used to test the temperature of the sample, the sample container, and the coolant. A circulating cooling heat exchange system forms a coolant circulation loop with the insulated box of the calorimeter to control the temperature of the test sample in the sample container. The computer control and analysis system is electrically connected to the atmosphere furnace and the circulating cooling heat exchange system, respectively.

[0010] Preferably, the atmosphere furnace is further provided with a multi-atmosphere ventilation pipeline communicating with the interior of the furnace chamber and a plurality of distributed thermocouples and heating elements uniformly distributed inside the furnace chamber. The multi-atmosphere ventilation pipeline is adapted to introduce oxidizing, reducing or inert atmosphere into the furnace chamber of the atmosphere furnace. The distributed thermocouples and the heating elements are electrically connected to the computer control and analysis system, respectively.

[0011] Preferably, the adjustable stage is located inside the connecting pipe and is equipped with a first automatic control valve electrically connected to the computer control and analysis system. The first automatic control valve is adapted to automatically open to allow the test sample to fall into the connecting pipe. The movable heat preservation furnace cover is equipped with a second automatic control valve electrically connected to the computer control and analysis system, located opposite the connecting pipe and the sample container. The second automatic control valve is adapted to automatically open to allow the test sample located in the connecting pipe to fall into the sample container.

[0012] Preferably, both the adjustable platform and the movable insulated furnace cover are made of heat-insulating refractory material, which is any one of alumina heat-insulating refractory bricks, high-alumina heat-insulating refractory bricks, clay heat-insulating refractory bricks, silica heat-insulating refractory bricks, and diatomaceous earth heat-insulating refractory bricks.

[0013] Preferably, the inner diameter of the connecting pipe is larger than the diameter of the test specimen, and the inner diameter of the sample container is not smaller than the inner diameter of the connecting pipe.

[0014] Preferably, when the temperature of the test sample is between 0-120°C, the coolant is water; when the temperature of the test sample is between 120-1800°C, the coolant is dimethicone oil with a viscosity of 450-550 cp; when the temperature of the test sample is between 0-1000°C, the sample container is made of copper; when the temperature of the test sample is between 1000-1200°C, the sample container is made of platinum; when the temperature of the test sample is between 1200-1800°C, the sample container is made of graphite; when the temperature of the test sample is between 0-1200°C, the mesh bag is made of alumina; and when the temperature of the test sample is between 1200-1800°C, the mesh bag is made of carbon fiber.

[0015] Preferably, the circulating cooling heat exchange system includes a first flow meter, a first control valve, a coolant compressor, a constant temperature coolant tank, a coolant pump, a three-way valve, and a second flow meter connected sequentially along the coolant flow direction. The end of the first flow meter away from the first control valve is connected to the medium outlet of the insulation tank, and the end of the second flow meter away from the three-way valve is connected to the medium inlet of the insulation tank. A first temperature measuring device is also connected to the pipeline between the three-way valve and the second flow meter, a second temperature measuring device is also connected to the pipeline between the first flow meter and the first control valve, and an exhaust safety valve is also connected to the pipeline between the first flow meter and the first control valve.

[0016] Preferably, the computer control and analysis system includes a temperature control module, an atmosphere control module, a valve control module, and a data processing module; the temperature control module is used to control the heating, holding, and cooling of the atmosphere furnace, wherein the heating rate of the atmosphere furnace is 8-12℃ / min, and after reaching the set temperature, it is held for 1.4-1.6 hours, and the cooling rate of the atmosphere furnace is 14-16℃ / min; the atmosphere control module is used to control the nitrogen flow rate introduced into the atmosphere furnace, wherein the nitrogen flow rate is 0.49-0.51 L / min. The air pressure is 0.1 MPa; the valve control module is electrically connected to the first automatic control valve and the second automatic control valve respectively; the data processing module includes a data acquisition unit, an image processing unit and a data calculation unit. The data acquisition unit is used to acquire and receive measurement data from the temperature sensor assembly, the first flow meter and the second flow meter. The image processing unit is used to generate a temperature change curve based on the acquired temperature data. The data calculation unit is used to calculate the heat storage density and specific heat capacity of the test sample according to the built-in heat storage density and specific heat capacity calculation formula.

[0017] The second objective of this invention is to provide a method for testing the heat storage performance of phase change heat storage refractory materials. This method utilizes the aforementioned testing equipment for phase change heat storage refractory materials and includes the following steps: S1: Preparing the phase change heat storage refractory material into a test sample. The test sample has a cylindrical structure with a diameter of Φ60–100 mm and a height of 40–50 mm; S2: Vacuuming or purging the atmosphere furnace and calorimeter before testing; S3: During the test, setting the heating rate, holding time, and cooling rate of the atmosphere furnace, and controlling these parameters via computer. The control and analysis system simultaneously opens the automatic control valves of the adjustable stage and the movable insulated furnace lid, allowing the test sample to fall into the calorimeter through the connecting pipe. After the pressure sensor detects the falling signal, the circulating cooling heat exchange system starts to introduce coolant. The computer-controlled analysis system times and collects the temperature and flow rate data of the coolant. S4: The computer-controlled analysis system calculates the heat storage density, specific heat capacity, phase change temperature, sensible heat, and latent heat of the test sample based on the collected temperature and flow rate data. S5: Repeat steps S1-S4 to calculate the average value and standard deviation of three identical test samples and determine whether the data is valid.

[0018] Preferably, the formula for calculating the heat storage density is:

[0019] The formula for calculating the specific heat capacity is:

[0020] The formula for calculating the heat carried away by the coolant is:

[0021] The heat storage capacity of the sample container and mesh bag is:

[0022] in: To test the heat storage density of the sample, To test the heat storage capacity of the sample, To test the mass of the sample, For specific heat capacity, T0 is the heat carried away by the coolant, and T0 is the test temperature of the atmosphere furnace heating. E To test the temperature of the sample, This refers to the coolant flow rate. This refers to the coolant outlet temperature. This refers to the coolant inlet temperature. This is the time it takes for the coolant to reach thermal equilibrium. It stores heat in the sample container and mesh bag.

[0023] Compared with the prior art, the present invention has the following advantages and effects: The phase change heat storage refractory material heat storage performance testing equipment of the present invention adopts intelligent control. The atmosphere furnace, calorimeter, circulating cooling heat exchange system and computer control analysis system are coordinated and linked. After the test sample is heated to the test temperature, the computer control analysis system automatically controls the adjustable stage and the movable heat-insulating furnace cover to open automatically. The test sample falls and triggers the pressure sensor, the circulating cooling heat exchange system starts automatically, and the computer control analysis system simultaneously times and collects data. After the test, the results are automatically exported, demonstrating a high degree of intelligence. The testing range of this equipment covers 0 to 1800℃. High-temperature heating of the test sample is achieved through a high-temperature atmosphere furnace, and the calorimeter selects an appropriate sample container and mesh bag according to the test temperature. The material meets the high-temperature testing requirements of phase change thermal storage refractory materials. The calorimeter uses a vacuum-insulated chamber, with the connecting pipes wrapped in insulating material to effectively reduce heat loss. It also considers the heat carried away by the coolant, the heat absorbed by the sample container, and the heat absorbed by the mesh bag, compensating for heat loss with standard samples, significantly reducing testing errors and further ensuring testing accuracy. This equipment can simultaneously test the phase change temperature, sensible heat, latent heat, total heat storage, and specific heat capacity of the sample. It identifies the phase change temperature through temperature change curves, distinguishing between latent heat in the phase change process and sensible heat in non-phase change processes, providing comprehensive data for material performance evaluation. The equipment has a wide range of applicable materials; it can test various thermal storage materials of suitable specifications and sizes, not only limited to phase change thermal storage refractory materials but also adaptable to the testing needs of different types of materials. Attached Figure Description

[0024] Figure 1 is a three-dimensional structural schematic diagram of the phase change thermal storage refractory material thermal storage performance testing equipment in an embodiment of the present invention; Figure 2 is a schematic diagram of the internal structure of the atmosphere furnace in an embodiment of the present invention; Figure 3 is a schematic diagram of the internal cross-sectional structure of the test sample before testing in an embodiment of the present invention; Figure 4 is a schematic diagram of the internal cross-sectional structure of the test sample during the falling process in an embodiment of the present invention; Figure 5 is a schematic diagram of the internal cross-sectional structure of the test sample falling into the bottom of the calorimeter in an embodiment of the present invention; Figure 6 is a three-dimensional structural schematic diagram of the adjustable stage in an embodiment of the present invention; Figure 7 is a three-dimensional structural schematic diagram of the movable heat-insulating furnace cover in an embodiment of the present invention; Figure 8 is a structural schematic diagram of the connecting pipe in an embodiment of the present invention; Figure 9 is a structural schematic diagram of the test sample in an embodiment of the present invention; Figure 10 is a structural schematic diagram of the circulating cooling heat exchange system in an embodiment of the present invention; Figure 11 is a structural framework schematic diagram of the computer control analysis system in an embodiment of the present invention; Figure 12 is a flowchart of the phase change thermal storage refractory material thermophysical property testing method in an embodiment of the present invention; Figure 13 is a temperature change curve of the sample and sample container in an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached drawings: 100-Test equipment; 1-Atmosphere furnace; 11-Lower opening; 12-Movable insulated furnace lid; 13-Connecting pipe; 14-Adjustable stage; 15-Multi-atmosphere ventilation pipe; 16-Distributed thermocouple; 17-Heating element; 2-Calligraphy device; 21-Insulated box; 211-Medium inlet; 212-Medium outlet; 22-Sample container; 23-Net bag; 24-Temperature sensor assembly; 241-First temperature sensor; 242-Second temperature sensor; 243-Third temperature sensor; 25-Pressure sensor; 26-Cooling 3- Circulating cooling heat exchange system; 31- First flow meter; 32- First control valve; 33- Coolant pump; 34- Constant temperature coolant tank; 35- Coolant pump; 36- Three-way valve; 37- Second flow meter; 38- First temperature measuring device; 39- Second temperature measuring device; 301- Exhaust safety valve; 4- Computer control and analysis system; 41- Temperature control module; 42- Atmosphere control module; 43- Valve control module; 44- Data processing module; 441- Data acquisition unit; 442- Image processing unit; 443- Data calculation unit; 5- Test sample. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be noted that the terms "comprising" and "including" as used herein should be understood as inclusive and open-ended, not exclusive. Specifically, when the terms "comprising" and "including" and their synonyms are used in the specification and claims, they indicate the inclusion of the specified features, steps, or components. These terms should not be construed as excluding the presence of other features, steps, or components.

[0028] Please refer to Figures 1-11. An embodiment of the present invention provides a phase change heat storage refractory material heat storage performance testing device 100. The testing device 100 includes an atmosphere furnace 1, a calorimeter 2, a circulating cooling heat exchange system 3, and a computer control and analysis system 4. The atmosphere furnace 1, the calorimeter 2, the circulating cooling heat exchange system 3, and the computer control and analysis system 4 work together to achieve accurate testing of the thermophysical properties of the phase change heat storage refractory material.

[0029] Please refer to Figures 1, 3, 4, and 5. The atmosphere furnace 1 has a lower opening 11 at the bottom of its furnace chamber. A movable heat-insulating furnace cover 12 is sealed and connected to the lower opening 11 to ensure the heating and heat preservation effect of the atmosphere furnace 1. The atmosphere furnace 1 has a connecting pipe 13 and an adjustable platform 14 inside its furnace chamber. The adjustable platform 14 is horizontally embedded in the furnace chamber of the atmosphere furnace 1. The connecting pipe 13 is vertically embedded in the inner wall of the lower opening 11 and extends upward to directly above the adjustable platform 14. The test sample 5 is suitable for being placed on the upper surface of the adjustable platform 14 and located at the inner top of the connecting pipe 13. The vertical central axes of the test sample 5, the connecting pipe 13, and the adjustable platform 14 are coincident. The adjustable platform 14 is located inside the connecting pipe 13 and has a first automatic control valve electrically connected to the computer control and analysis system 4 to facilitate the accurate fall of the test sample 5 to the calorimeter device 2 through the connecting pipe 13.

[0030] Preferably, the inner diameter of the connecting pipe 13 is larger than the diameter of the test sample 5, and the inner diameter of the sample container 22 is not smaller than the inner diameter of the connecting pipe 13.

[0031] Specifically, as shown in Figures 6 and 7, in one embodiment of the present invention, the base of the adjustable stage 14 is movably set, and the inner diameter of the connecting pipe 13 is about 3mm larger than the diameter of the test sample 5. This ensures that the test sample 5 falls into the sample container 22 of the calorimeter 2 and fits against the inner wall of the sample container 22.

[0032] Specifically, in one embodiment of the present invention, the adjustable platform 14 and the movable heat-insulating furnace cover 12 are both made of heat-insulating refractory material, which is any one of alumina heat-insulating refractory bricks, high-alumina heat-insulating refractory bricks, clay heat-insulating refractory bricks, silica heat-insulating refractory bricks and diatomaceous earth heat-insulating refractory bricks.

[0033] It should be noted that the adjustable stage 14 is used to place the standard sample and the phase change heat storage refractory material to be tested, and the adjustable stage 14 is located inside the atmosphere furnace 1. Therefore, the adjustable stage 14 is generally made of heat-insulating refractory material.

[0034] The atmosphere furnace 1 is also equipped with a multi-atmosphere ventilation pipeline 15, which can introduce oxidizing, reducing or inert atmospheres to meet the needs of different testing environments. The furnace chamber is equipped with multiple sets of distributed thermocouples 16 and heating elements 17. The distributed thermocouples 16 are electrically connected to the computer control and analysis system 4 to realize accurate temperature monitoring and control, and can heat the test sample 5 to a temperature range of 0 to 1800℃.

[0035] The connecting pipe 13 is used to connect the adjustable stage 14 to the calorimeter 2, ensuring that the test sample 5 falls into the sample container 22 of the calorimeter 2. The outer part of the connecting pipe 13 is also wrapped with heat insulation material to reduce heat loss during the sample's descent. The size of the connecting pipe 13 is about 3mm larger than the diameter of the test sample 5, which ensures that the test sample 5 passes smoothly while reducing heat loss.

[0036] Therefore, the temperature control function of atmosphere furnace 1 (heating rate, holding time and cooling rate are controllable) can reproduce the state of phase change heat storage refractory materials under different high temperature scenarios, ensuring that the test environment is consistent with the actual application scenario and avoiding the distortion of test results due to environmental differences; the computer control and analysis system 4 receives temperature data synchronously and can generate a more comprehensive test report, providing richer evidence for the evaluation of the material's heat storage performance.

[0037] Please refer to Figures 1, 3, 4, and 5. In one embodiment of the present invention, the calorimetric device 2 includes an insulated box 21, a sample container 22, a net bag 23, a temperature sensor assembly 24, and a pressure sensor 25. The sample container 22 is a pipe structure with an open top, and its inner diameter is greater than or equal to the inner diameter of the connecting pipe 13. The upper opening of the sample container 22 is sealed by a movable insulated furnace cover 12. To ensure that the test sample 5 falls into the sample container 22 of the calorimetric device 2, the vertical central axis of the sample container 22 coincides with the connecting pipe 13. The movable insulated furnace cover 12 is provided with a second automatic control valve that can be automatically opened and closed and is suitable for the free passage of the test sample 5. The second automatic control valve automatically opens to allow the test sample 5 located in the connecting pipe 13 to fall smoothly into the sample container 22. The net bag 23 is fixed to the inner bottom of the sample container 22 to prevent the test sample 5 from falling and damaging the sample container 22.

[0038] Specifically, in this embodiment, the insulated box 21 is a stainless steel insulated inner liner structure with a vacuum partition. The inner wall surface of the insulated box 21 is silver-plated or copper-plated. The insulated box 21 completely covers the outside of the sample container 22, suspending the sample container 22 inside the insulated box 21. The top of the insulated box 21 is sealed to the bottom surface of the movable insulated furnace lid 12. The opposite side walls of the insulated box 21 are respectively provided with a medium inlet 211 and a medium outlet 212 communicating with the inside of the insulated box 21. In this embodiment, the test temperature of the test sample 5 is 1500℃, so coolant 26 is added to the inside of the insulated box 21. The coolant 26 flows into the inside of the insulated box 21 from the medium inlet 211 to exchange heat with the suspended sample container 22, and flows out of the insulated box 21 from the medium outlet 212.

[0039] As a preferred embodiment, the coolant 26 is dimethicone oil with a viscosity of 500 cp, the sample container 22 is made of graphite, and the mesh bag 23 is made of carbon fiber.

[0040] The temperature sensor assembly 24 includes a first temperature sensor 241 for testing the temperature of the sample 5, a second temperature sensor 242 for testing the temperature of the sample container 22, and a third temperature sensor 243 for testing the temperature of the coolant 26. Considering the accuracy of the measurement, the measurement accuracy of the first temperature sensor 241, the second temperature sensor 242, and the third temperature sensor 243 in this embodiment is ±0.01℃.

[0041] Pressure sensor 25 is connected to net bag 23 to monitor the test sample 5 falling into calorimeter device 2.

[0042] Preferably, when the temperature of the test sample 5 is between 0-120℃, the coolant 26 is water; when the temperature of the test sample 5 is between 120-1800℃, the coolant 26 is dimethicone oil with a viscosity of 450-550cp. Specifically, in the temperature range of 0-120℃, water is used as the coolant because water has a high specific heat capacity and thermal conductivity, which can quickly remove heat in the medium and low temperature range, meet the heat dissipation requirements of the sample at 0-120℃, and maintain temperature stability. In addition, water is widely available and inexpensive, and its chemical properties are stable in this temperature range, making it less likely to react with surrounding components, thus reducing testing costs and maintenance difficulty.

[0043] Dimethicone can be used for extended periods from -50℃ to 200℃. It is not easily decomposed or deteriorated in high-temperature environments of 120-1800℃, and can maintain stable cooling performance, avoiding temperature runaway caused by coolant failure. Its viscosity of 450-550cp can maintain good fluidity at high temperatures, allowing it to evenly cover the sample surface and achieve efficient heat dissipation, while avoiding leakage and excessive volatilization problems caused by excessively low viscosity.

[0044] Preferably, when the temperature of the test sample 5 is between 0-1000℃, the sample container 22 is made of copper; when the temperature of the test sample 5 is between 1000-1200℃, the sample container 22 is made of platinum; and when the temperature of the test sample 5 is between 1200-1800℃, the sample container 22 is made of graphite.

[0045] Specifically, within a temperature range of 0-1000℃, copper is used as the material for sample container 22. Copper has a high thermal conductivity, enabling rapid heat transfer and ensuring uniform heating of the sample, thus guaranteeing accurate test results. This is particularly suitable for medium- and low-temperature testing scenarios where high temperature uniformity is required. Furthermore, copper is easily processed into containers of various shapes to meet the testing needs of different samples, and it is not easily deformed within the 0-1000℃ range, ensuring the structural integrity of the container. Compared to materials such as platinum and graphite, copper can reduce the manufacturing cost of testing equipment, making it suitable for large-scale applications.

[0046] Platinum, used as the material for sample container 22, maintains stable physical and chemical properties at high temperatures of 1000-1200℃. With a melting point as high as 1772℃, platinum is resistant to strong acids and alkalis and will not chemically react with the sample, ensuring the sample purity remains unaffected. Furthermore, its minimal expansion upon heating ensures dimensional stability of the container, preventing breakage or leakage due to thermal expansion and contraction, thus extending its service life.

[0047] Within a temperature range of 1200-1800℃, graphite, as the material for sample container 22, exhibits structural stability at high temperatures of approximately 3650℃, without softening or melting, thus withstanding extreme high-temperature testing. Furthermore, graphite has an extremely low coefficient of thermal expansion, making it less prone to cracking during rapid heating or cooling, allowing it to adapt to temperature fluctuations in high-temperature testing and ensuring the safety and reliability of the container.

[0048] Preferably, when the temperature of the test sample 5 is between 0-1200℃, the material of the net bag 23 is alumina, and when the temperature of the test sample 5 is between 1200-1800℃, the material of the net bag 23 is carbon fiber.

[0049] Specifically, alumina can withstand long-term operating temperatures of 1200-1600℃ and maintains structural stability within the 0-1200℃ range, preventing damage from high temperatures and effectively supporting the sample. Furthermore, alumina fibers have high tensile strength and maintain a certain rigidity even at high temperatures, preventing deformation of the mesh; simultaneously, their low thermal conductivity reduces heat transfer through the mesh, avoiding excessive impact on the sample temperature.

[0050] Carbon fiber exhibits stable performance at high temperatures of 1200-1800℃ and has a low coefficient of thermal expansion, enabling it to withstand drastic temperature changes without easily cracking or deforming, thus ensuring the reliability of the mesh bag 23 in extreme high-temperature environments. Furthermore, carbon fiber's high strength and low density allow it to withstand significant loads at high temperatures while reducing the weight of the mesh bag itself, preventing excessive pressure on the sample and making it suitable for high-temperature testing of heavier samples.

[0051] Please refer to Figure 10. In one embodiment of the present invention, the circulating cooling heat exchange system 3 includes a first flow meter 31, a first control valve 32, a coolant pump 33, a constant temperature coolant tank 34, a coolant pump 35, a three-way valve 36, and a second flow meter 37 connected sequentially along the coolant flow direction. The end of the first flow meter 31 away from the first control valve 32 is connected to the medium outlet 212 of the insulation box 21, and the end of the second flow meter 37 away from the three-way valve 36 is connected to the medium inlet 211 of the insulation box 21. In this way, a coolant circulation loop is formed between the circulating cooling heat exchange system 3 and the insulation box 21.

[0052] To measure the coolant temperature at the medium inlet 211 of the insulation box 21, a first temperature measuring device 38 is connected to the pipeline between the three-way valve 36 and the second flow meter 37. To monitor the coolant temperature at the medium outlet 212 of the insulation box 21, a second temperature measuring device 39 is connected to the pipeline between the first flow meter 31 and the first control valve 32. In addition, to ensure the safety of the circulating cooling heat exchange system 3, an exhaust safety valve 301 is connected to the pipeline between the first flow meter 31 and the first control valve 32.

[0053] Please refer to Figure 11. In one embodiment of the present invention, the computer control and analysis system 4 includes a temperature control module 41, an atmosphere control module 42, a valve control module 43, and a data processing module 44. The temperature control module 41 is used to control the heating, holding, and cooling of the atmosphere furnace 1. The heating rate of the atmosphere furnace 1 is preferably 10°C / min. After reaching the set temperature, it is held for 1.5 hours. The cooling rate of the atmosphere furnace 1 is 15°C / min.

[0054] The atmosphere control module 42 is used to control the flow rate of nitrogen gas. In this embodiment, the nitrogen flow rate is preferably 0.5 L / min and the gas pressure is 0.1 MPa.

[0055] The valve control module 43 is electrically connected to the electrically controlled valves on the adjustable platform 14 and the movable insulation furnace cover 12, respectively, to control the opening and closing of the electrically controlled valves on the adjustable platform 14 and the movable insulation furnace cover 12. It should be noted that the electrical connection is located outside the furnace, and the opening and closing of the electrically controlled valves on the adjustable platform 14 and the movable insulation furnace cover 12 is controlled by an electrically controlled telescopic mechanism, effectively avoiding the electrical connection being located in an extreme temperature environment.

[0056] Please refer to Figure 11. In one embodiment of the present invention, the data processing module 44 includes a data acquisition unit 441, an image processing unit 442, and a data calculation unit 443. The data acquisition unit 441 acquires and receives measurement data from the temperature sensor assembly 24, the first flow meter 31, and the second flow meter 37. The image processing unit 442 is used to plot and generate a temperature change curve based on the acquired temperature data. The data calculation unit 443 is used to calculate the heat storage density and specific heat capacity according to the built-in heat storage density and specific heat capacity calculation formulas.

[0057] Understandably, the data acquisition unit 441 is used to achieve synchronous and automated acquisition of multi-source data, avoiding delays or reading errors when manually recording temperature; the data calculation unit 443 automatically calculates using built-in heat storage density and specific heat calculation formulas, replacing manual calculation and significantly improving the accuracy of data processing; the image processing unit 442 is used to generate temperature change curves based on the acquired temperature, making the test conclusions more convincing.

[0058] Please refer to Figure 12. Another embodiment of the present invention also provides a method for testing the thermophysical properties of phase change heat storage refractory materials. Using the above-mentioned testing equipment, the testing method includes the following steps: S1: In the sample preparation process, the phase change heat storage refractory material is prepared into a test sample 5. The test sample 5 is set as a cylindrical structure with a diameter of Φ60~100mm and a height L of 50~80mm.

[0059] In this step, the diameter of the test specimen 5 is preferably 60mm, the height of the test specimen 5 is preferably 60mm, and the deviation of the height and diameter of the test specimen 5 is ±0.8mm, the deviation of the parallel plane is 0.3mm, and the edges and corners of the test specimen 5 are perpendicular, without cracks, and the surface is flat and clean.

[0060] S2: Before testing, the atmosphere furnace 1 and calorimeter 2 are controlled by the computer control and analysis system 4 to perform vacuum treatment. After the vacuum degree reaches -0.09MPa, nitrogen is introduced to replace the atmosphere. After replacement 3 times, the nitrogen atmosphere is maintained.

[0061] S3: During the test, the computer control and analysis system 4 sets the heating rate of the atmosphere furnace 1 to 10℃ / min, heats the atmosphere furnace 1 to 1500℃ and holds it for 1.5h. During the holding period, the temperature fluctuation is controlled within ±3℃. Then, the computer control and analysis system 4 controls the electric valves of the adjustable stage 14 and the movable heat preservation furnace cover 12 to open simultaneously. The test sample 5 falls into the sample container 22 of the calorimeter device 2 along the connecting pipe 13. After the pressure sensor 25 detects the falling signal, it controls the circulation cooling heat exchange system 3 to start. The coolant pump 35 pumps the dimethyl silicone oil in the constant temperature coolant tank 34 into the heat preservation box 21. The computer control and analysis system 4 starts timing and continuously collects the temperature data of the first temperature sensor 241, the second temperature sensor 242 and the third temperature sensor 243, as well as the flow data of the first flow meter 31 and the second flow meter 37. The data is collected continuously for 2h until thermal equilibrium is reached.

[0062] In this step, the prepared test sample 5 is placed on the adjustable stage 14 inside the atmosphere furnace 1; the atmosphere type (oxidizing, reducing, or inert environment) is set through the computer control and analysis system 4; the heating rate of the atmosphere furnace 1 is set simultaneously, and the atmosphere furnace 1 is heated to the test temperature T0, and held at that temperature for more than 1 hour to ensure the temperature of the test sample 5 is stable, with temperature fluctuations not exceeding ±5℃ during the holding period; after reaching the test temperature and time, the circulating cooling heat exchange system 3 is turned on 5 minutes in advance, and the first automatic control valve of the adjustable stage 14 and the second automatic control valve of the movable heat-insulating furnace cover 12 are opened simultaneously through the valve control module 43. The test sample 5 falls into the sample container 22 of the calorimeter 2 through the connecting pipe 13 and the movable heat-insulating furnace cover 12. The pressure sensor 25 at the bottom of the sample container 22 sends the gravity signal of the test sample 5 to the computer control and analysis system 4 after sensing it. At this time, the temperature of the calorimeter 2 is T1, and the temperature T of the test sample 5 inside the calorimeter 2 is collected through the data acquisition unit 441. E The crucible temperature T3 and the circulating water inlet and outlet flow rates q t The circulating water inlet temperature T1, the circulating water outlet temperature T2, and the time t for the circulating water to reach thermal equilibrium. E .

[0063] It should be noted that the test temperature range is 0 to 2000℃, which can be determined according to the actual service temperature of the sample.

[0064] S4: The computer-controlled analysis system 4 calculates the heat storage density, specific heat capacity, phase change temperature, sensible heat, and latent heat of the test sample 5 based on the collected temperature and flow rate data.

[0065] In this step, the heat storage density and specific heat calculation module of data calculation unit 443 calculates according to the following formula: As shown in Figure 13, the test temperature is higher than the phase change temperature, the time to reach the phase change temperature is t0, the phase change ends at t1, and the time to reach equilibrium is t E The sensible heat of the test sample temperature is higher than the phase transition temperature.

[0066] Q x1 To test the heat storage from the test temperature to the phase transition temperature; The heat carried away by the coolant over time t0; Time t0: Heat storage in the sample container and mesh bag; The heat absorbed by the insulated box and other components over time t0;

[0067]

[0068] The latent heat of phase transition is

[0069] Among them: Q x2 For heat storage during phase transition; The heat carried away by the coolant over time t1; Time t1: Heat storage in the sample container and mesh bag; The heat absorbed by the insulated box and other components over time t1;

[0070]

[0071] After the phase transition, it is obvious

[0072] Q x3 To store heat to balance the temperature to the phase change temperature; For time t E The heat carried away by the coolant; Time t E Sample containers and mesh bags store heat; Time t E Heat absorbed by the insulated box and other components;

[0073]

[0074] Total heat storage of the sample

[0075]

[0076] Heat storage density

[0077] It refers to the mass of the sample; It is the heat storage capacity of the sample; It is the heat storage density of the sample.

[0078] The formula for calculating specific heat capacity is as follows:

[0079] in, Heat carried away by the circulating water:

[0080] For circulating water flow rate, For the outlet temperature, Inlet temperature, The time required to reach thermal equilibrium.

[0081] Sample container and mesh bag for heat storage for:

[0082] The amount of heat absorbed by the insulated box and other components is determined through standard sample testing.

[0083] Therefore, the heat storage density of test sample 5 was calculated to be 1200 kJ / m³, and the specific heat capacity was 1.1 kJ / (kg·m³). K), phase transition temperature is 850℃, sensible heat is 700kJ / kg, latent heat is 350kJ / kg.

[0084] S5: Repeat steps S1-S4 to calculate the average and standard deviation of the three identical test samples 5, and determine whether the data is valid.

[0085] In this step, the values ​​of 3 test samples 5 are calculated simultaneously. and The mean and standard deviation are as follows: the mean is 1180 kJ / m³ and the standard deviation is 95 kJ / m³. If the standard deviation is less than 10% of the mean, the data is considered valid; otherwise, the sample needs to be prepared again and tested.

[0086] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this invention.

Claims

1. A device for testing the heat storage performance of phase change heat storage refractory materials, characterized in that, The system includes an atmosphere furnace, a calorimeter, a circulating cooling heat exchange system, and a computer control and analysis system. The atmosphere furnace has a lower opening at the bottom of its furnace chamber, and a movable, insulated furnace cover is sealed at the lower opening. The atmosphere furnace has a vertically embedded connecting pipe on the inner wall of the lower opening and a horizontally embedded adjustable platform on the side wall of the furnace chamber. The connecting pipe extends vertically upwards to directly above the adjustable platform. The test sample is suitable for placement on the upper surface of the adjustable platform and located at the inner top of the connecting pipe, and the vertical central axes of the test sample, the connecting pipe, and the adjustable platform coincide. The thermal device includes an insulated box sealed to the bottom surface of the movable insulated furnace lid, a sample container suspended inside the insulated box, a mesh bag fixed to the bottom of the sample container, a temperature sensor assembly, and a pressure sensor connected to the mesh bag. The insulated box is filled with coolant. The temperature sensor assembly is used to test the temperature of the sample, the sample container, and the coolant. A circulating cooling heat exchange system forms a coolant circulation loop with the insulated box of the calorimeter to control the temperature of the test sample in the sample container. The computer control and analysis system is electrically connected to the atmosphere furnace and the circulating cooling heat exchange system, respectively.

2. The testing equipment for the heat storage performance of phase change heat storage refractory materials according to claim 1, characterized in that, The atmosphere furnace is also equipped with a multi-atmosphere ventilation pipeline communicating with the interior of the furnace chamber, as well as multiple sets of distributed thermocouples and heating elements evenly distributed inside the furnace chamber. The multi-atmosphere ventilation pipeline is adapted to introduce oxidizing, reducing, or inert atmospheres into the furnace chamber of the atmosphere furnace. The distributed thermocouples and the heating elements are electrically connected to the computer control and analysis system, respectively.

3. The testing equipment for the heat storage performance of phase change heat storage refractory materials according to claim 1, characterized in that, The adjustable stage is located inside the connecting pipe and is equipped with a first automatic control valve electrically connected to the computer control and analysis system. The first automatic control valve is adapted to automatically open to allow the test sample to fall into the connecting pipe. The movable heat preservation furnace cover is equipped with a second automatic control valve electrically connected to the computer control and analysis system, located directly opposite the connecting pipe and the sample container. The second automatic control valve is adapted to automatically open to allow the test sample located inside the connecting pipe to fall into the sample container.

4. The testing equipment for the heat storage performance of phase change heat storage refractory materials according to claim 1, characterized in that, Both the adjustable platform and the movable insulated furnace cover are made of heat-insulating refractory material, which is any one of alumina heat-insulating refractory bricks, high-alumina heat-insulating refractory bricks, clay heat-insulating refractory bricks, silica heat-insulating refractory bricks, and diatomaceous earth heat-insulating refractory bricks.

5. The testing equipment for the heat storage performance of phase change heat storage refractory materials according to claim 1, characterized in that, The inner diameter of the connecting pipe is larger than the diameter of the test specimen, and the inner diameter of the sample container is not smaller than the inner diameter of the connecting pipe.

6. The testing equipment for the heat storage performance of phase change heat storage refractory materials according to claim 1, characterized in that, When the temperature of the test sample is between 0-120℃, the coolant is water; when the temperature of the test sample is between 120-1800℃, the coolant is dimethicone oil with a viscosity of 450-550cp; when the temperature of the test sample is between 0-1000℃, the sample container is made of copper; when the temperature of the test sample is between 1000-1200℃, the sample container is made of platinum; when the temperature of the test sample is between 1200-1800℃, the sample container is made of graphite; when the temperature of the test sample is between 0-1200℃, the net is made of alumina; when the temperature of the test sample is between 1200-1800℃, the net is made of carbon fiber.

7. The heat storage performance testing equipment for phase change heat storage refractory materials according to claim 3, characterized in that, The circulating cooling heat exchange system includes a first flow meter, a first control valve, a coolant compressor, a constant temperature coolant tank, a coolant pump, a three-way valve, and a second flow meter connected sequentially along the coolant flow direction. The end of the first flow meter away from the first control valve is connected to the medium outlet of the insulation tank, and the end of the second flow meter away from the three-way valve is connected to the medium inlet of the insulation tank. A first temperature measuring device is also connected to the pipeline between the three-way valve and the second flow meter, a second temperature measuring device is also connected to the pipeline between the first flow meter and the first control valve, and an exhaust safety valve is also connected to the pipeline between the first flow meter and the first control valve.

8. The testing equipment for the thermal storage performance of phase change thermal storage refractory materials according to claim 7, characterized in that, The computer control and analysis system includes a temperature control module, an atmosphere control module, a valve control module, and a data processing module. The temperature control module controls the heating, holding, and cooling of the atmosphere furnace. The heating rate of the atmosphere furnace is 8-12℃ / min, and after reaching the set temperature, it is held for 1.4-1.6 hours. The cooling rate of the atmosphere furnace is 14-16℃ / min. The atmosphere control module controls the nitrogen flow rate introduced into the atmosphere furnace. The nitrogen flow rate is 0.49-0.51 L / min, and the gas pressure is... The pressure is 0.1 MPa; the valve control module is electrically connected to the first automatic control valve and the second automatic control valve respectively; the data processing module includes a data acquisition unit, an image processing unit and a data calculation unit. The data acquisition unit is used to acquire and receive measurement data from the temperature sensor assembly, the first flow meter and the second flow meter. The image processing unit is used to generate a temperature change curve based on the acquired temperature data. The data calculation unit is used to calculate the heat storage density and specific heat capacity of the test sample according to the built-in heat storage density and specific heat capacity calculation formula.

9. A method for testing the heat storage performance of phase change heat storage refractory materials, using the heat storage performance testing equipment for phase change heat storage refractory materials as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: Prepare a test specimen from the phase change heat storage refractory material. The test specimen has a cylindrical structure with a diameter of Φ60-100mm and a height of 40-50mm. S2: Before testing, evacuate or purge the atmosphere furnace and calorimeter. S3: During testing, set the heating rate, holding time, and cooling rate of the atmosphere furnace. The computer control and analysis system simultaneously opens the automatic control valves of the adjustable platform and the movable heat-insulating furnace lid. The test specimen falls into the calorimeter through a connecting pipe. After the pressure sensor detects the falling signal, the circulating cooling heat exchange system begins to circulate coolant. The computer control and analysis system times and collects the temperature and flow rate data of the coolant. S4: The computer control and analysis system calculates the heat storage density, specific heat capacity, phase change temperature, sensible heat, and latent heat of the test specimen based on the collected temperature and flow rate data. S5: Repeat steps S1-S4 to calculate the average and standard deviation of three identical test specimens and determine the validity of the data.

10. The method for testing the heat storage performance of phase change heat storage refractory materials according to claim 9, characterized in that, The formula for calculating the heat storage density is: The formula for calculating the specific heat capacity is: The formula for calculating the heat carried away by the coolant is: The heat storage capacity of the sample container and mesh bag is: in: To test the heat storage density of the sample, To test the heat storage capacity of the sample, To test the mass of the sample, For specific heat capacity, T0 is the heat carried away by the coolant, and T0 is the test temperature of the atmosphere furnace heating. E To test the temperature of the sample, This refers to the coolant flow rate. This refers to the coolant outlet temperature. This refers to the coolant inlet temperature. This is the time it takes for the coolant to reach thermal equilibrium. It stores heat in the sample container and mesh bag.

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