A thermal physical property testing apparatus for phase change energy storage panels and methods of use

Abstract

This invention discloses a thermophysical performance testing device for phase change energy storage panels and its usage method, relating to the field of thermophysical performance testing technology for building materials. The testing device includes two measuring devices connected by tie bolts to a support frame, the two devices being symmetrically placed. Each measuring device includes a variable-temperature constant-temperature water circulation tank and a testing unit, the variable-temperature constant-temperature water circulation tank being connected to the testing unit via water pipes. The testing unit includes, from the inside out, a support pressure plate, an insulation box, a heat exchanger, a thermally conductive silicone pad, and a heat flux sensor. The tie bolts to the support pressure plate are mounted on the support frame using support nuts. Utilizing the principles of heat transfer, this device can provide clear test results for multiple thermophysical performance parameters of the phase change energy storage panel.

Description

Technical Field

[0001] This invention relates to the field of thermophysical performance testing technology for building materials, and more specifically to a thermophysical performance testing device for a phase change energy storage plate and its usage method. Background Technology

[0002] Heating and cooling energy consumption accounts for more than half of the total energy consumption during the building's lifespan. Strengthening the thermal insulation performance of the building envelope is a common method for building energy conservation. Insulation materials are mostly lightweight and porous, which can reduce heat transfer through the building envelope, but their effect on improving heat storage capacity is limited. Enhancing the heat storage capacity of the building envelope not only attenuates and delays temperature fluctuations, but also has a significant impact on indoor temperature regulation and energy conservation.

[0003] Currently used building materials such as concrete, mortar, insulation boards, and gypsum boards are all common building materials, meaning their thermophysical properties change very little with temperature variations. Commercially available equipment for testing the thermal performance of building materials, such as heat storage coefficient testers and thermal conductivity testers, as well as relevant national standards, are all designed for common building materials.

[0004] Phase change energy storage panels (PCS) maintain a constant temperature after reaching their phase change temperature, absorbing heat from the building environment through their latent heat and thus regulating room temperature. However, their thermophysical properties change significantly with temperature variations. While some engineers use digital subtraction angiography (DSC) to test the thermophysical properties of PCS materials, DSC tests can only measure samples smaller than 10 milligrams, and PCS panels may contain pores or have unique material structures. Currently available testing equipment cannot provide results for the thermophysical properties of PCS panels, such as phase change temperature, specific heat capacity, and latent heat.

[0005] Therefore, designing a thermophysical performance testing device for phase change energy storage panels and its usage method, and accurately measuring multiple physical performance parameters of phase change energy storage panels, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] In view of this, the present invention provides a thermophysical performance testing device for phase change energy storage panels and a method for using the device, which can measure multiple physical characteristic parameters of phase change energy storage panels.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] On one hand, the present invention discloses a thermophysical performance testing device for a phase change energy storage plate, comprising: two measuring devices connected by tie bolts through a bracket, the two measuring devices being placed symmetrically;

[0009] The measuring device includes a variable constant temperature water circulation tank and a testing unit, wherein the variable constant temperature water circulation tank is connected to the testing unit via a water pipe;

[0010] The test unit includes, from the inside out, a support pressure plate, an insulation box, a heat exchanger, a thermally conductive silicone pad, and a heat flux sensor;

[0011] The bracket tie bolts are installed on the bracket pressure plate via bracket nuts.

[0012] Preferably, the variable constant temperature water circulation tank is connected to the heat exchanger via a water pipe.

[0013] Preferably, the thermophysical performance testing equipment for phase change energy storage panels further includes a data recording unit, which is connected to the heat flux sensor.

[0014] Preferably, the thermophysical performance testing equipment for the phase change energy storage plate applies pressure by rotating the support nut.

[0015] Preferably, the variable constant temperature water circulation tank is equipped with a temperature control system;

[0016] The variable constant temperature water circulation tank is equipped with a heater and a refrigeration compressor.

[0017] The temperature control system controls the operation of the heater or refrigeration compressor.

[0018] On the other hand, the present invention also discloses a method for using the thermophysical performance testing equipment of the above-mentioned phase change energy storage plate, comprising the following steps:

[0019] After drying, the phase change energy storage panel under test is allowed to cool naturally to room temperature;

[0020] The phase change energy storage plate to be tested is placed between two heat flux sensors of the thermophysical performance testing equipment for phase change energy storage plates.

[0021] Rotate the support nut in the thermophysical performance testing equipment to apply pressure to the phase change energy storage plate under test;

[0022] Turn on the variable constant temperature water circulation tank and data recording unit in the thermophysical performance testing equipment to test the phase change performance and thermal conductivity.

[0023] Preferably, the phase change performance test includes:

[0024] Set the initial temperature and target temperature;

[0025] The initial temperature is kept constant for a certain period of time until the heat flux no longer fluctuates.

[0026] Once the heat flux stabilizes, heat or cool at a constant rate of temperature change until the target temperature is reached.

[0027] The heat flux and time data of the entire process are recorded by the data recording unit, and the phase change performance is calculated.

[0028] Preferably, the phase change properties include specific heat capacity, latent heat, and thermal inertia.

[0029] Preferably, the thermal conductivity test includes:

[0030] The two heat exchangers in the thermophysical performance testing equipment are kept at a constant temperature, and there is a temperature difference between the two heat exchangers. The heat flux is observed until the fluctuation stops. The heat flux values ​​on both sides of the phase change energy storage plate under test are read respectively, and the thermal conductivity is calculated.

[0031] As can be seen from the above technical solution, compared with the prior art, this invention discloses a thermophysical performance testing device for phase change energy storage panels and its usage method. The testing device includes two measuring devices connected by tie bolts to a bracket, and the two measuring devices are placed symmetrically. The measuring device includes a variable temperature constant temperature water circulation tank and a testing unit. The variable temperature constant temperature water circulation tank is connected to the testing unit through a water pipe. The testing unit includes a bracket pressure plate, an insulation box, a heat exchanger, a thermally conductive silicone pad, and a heat flux sensor arranged sequentially from the inside to the outside. The tie bolts to the bracket pressure plate are installed by bracket nuts. Utilizing the principles of heat transfer, this device can provide clear test results for multiple thermophysical performance parameters of the phase change energy storage panel. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 A schematic diagram of the thermophysical performance testing equipment for the phase change energy storage plate provided by the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of the test unit of the present invention;

[0035] Figure 3 The figure shows the test results of the specific heat capacity of the phase change energy storage plate and the constant property plate provided in the embodiment of the present invention.

[0036] In the diagram, 1-Variable temperature constant temperature water circulation tank; 12-Temperature control system; 13-Water pipe; 21-Insulation box; 22-Heat exchanger; 221-Heat exchanger inlet; 23-Thermal conductive silicone pad; 24-Heat flux sensor; 25-Phase change energy storage plate under test; 31-Support pressure plate; 32-Support tie bolt; 33-Support nut. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0038] On one hand, embodiments of the present invention disclose a thermophysical performance testing device for a phase change energy storage plate, the structure of which is as follows: Figure 1 As shown, it includes two measuring devices connected by tie bolts 32 on a bracket, and the two measuring devices are placed symmetrically.

[0039] The measuring device includes a variable constant temperature water circulation tank 1 and a testing unit. The variable constant temperature water circulation tank 1 is connected to the testing unit through a water pipe 13. In this embodiment, the variable constant temperature water circulation tank 1 can use water, oil, or alcohol as the heat transfer medium. Specifically, the variable constant temperature water circulation tank 1 can maintain a constant temperature and can also heat or cool the water at a constant rate. The heating / cooling rate is 0.05℃ / min to 2℃ / min, with an accuracy of 0.02℃.

[0040] A temperature control system 12 is installed on the variable temperature constant temperature water circulation tank 1;

[0041] The variable temperature constant temperature water circulation tank 1 is equipped with a heater, a refrigeration compressor, a water pump, a water tank, water pipes, and a control panel;

[0042] Temperature control system 12 controls the operation of heater or refrigeration compressor.

[0043] Test Unit Structure Reference Figure 2 It includes a support pressure plate 31, an insulation box 21, a heat exchanger 22, a thermally conductive silicone pad 23, and a heat flux sensor 24 arranged sequentially from the inside to the outside; wherein, the insulation box 21 is filled with polyethylene foam and rock wool, the heat exchanger 22 is made of stainless steel, and the thermally conductive silicone pad 23 has a thermal conductivity of 5w / m·K.

[0044] The bracket tie bolt 32 is installed on the bracket pressure plate 31 via the bracket nut 33.

[0045] Specifically, the variable temperature constant temperature water circulation tank 1 is connected to the heat exchanger 22 through the water pipe 13. In this embodiment, the variable temperature constant temperature water circulation tank 1 transports water from the water tank to the heat exchanger 22 through the water pipe 13 and the heat exchanger inlet 221. The water flow rate is 0.5 liters per second.

[0046] The thermophysical performance testing equipment for phase change energy storage panels also includes a data recording unit, which is connected to a heat flux sensor 24. The data recording unit can continuously collect heat flux and display the heat flux status in real time. The sensor is 0.3 mm thick.

[0047] The thermophysical performance testing equipment for phase change energy storage plates applies pressure by rotating the support nut 33. In this embodiment, the applied pressure is 50N.

[0048] On the other hand, embodiments of the present invention also disclose a method for using a thermophysical performance testing device for a phase change energy storage plate, comprising the following steps:

[0049] S1. After drying the phase change energy storage plate to be tested, allow it to cool naturally to room temperature.

[0050] Take a flat phase change energy storage plate with dimensions of 200×200×15mm as the phase change energy storage plate to be tested. Place it in a drying oven and dry it at 100℃ for 72 hours. After drying, allow it to cool naturally to room temperature and weigh the phase change energy storage plate to be tested.

[0051] S2. Place the phase change energy storage plate to be tested between the two heat flux sensors of the phase change energy storage plate thermophysical performance testing equipment.

[0052] S3. The bracket nut in the rotating thermophysical performance testing equipment presses the bracket pressure plate, thereby applying pressure to the phase change energy storage plate to be tested. In this embodiment, the pressure is 50N.

[0053] S4. Turn on the variable constant temperature water circulation tank and data recording unit in the thermophysical performance testing equipment to test the phase change performance and thermal conductivity.

[0054] Specifically, testing phase transition performance includes:

[0055] S411. Set the initial temperature and target temperature;

[0056] This embodiment tests the thermophysical performance of the variable phase energy storage panel under test in the range of 5 to 45°C. The initial temperature is set to 5°C and the target temperature is 45°C.

[0057] S412. Maintain a constant temperature of 5°C for 20 minutes until the heat flux no longer fluctuates.

[0058] S413. After the heat flux stabilizes, heat or cool at a constant rate of temperature change until the target temperature is reached.

[0059] In this embodiment, heating is performed at a constant rate of 0.2°C / min until the water temperature reaches 45°C.

[0060] S414. Record the heat flux and time data of the entire process (within the range of 5 to 45°C) through the data recording unit, and calculate the phase change performance, including specific heat capacity, latent heat, thermal inertia, phase change initiation temperature, and phase change end temperature.

[0061] Specifically, specific heat capacity C p The formula for calculating (t) is as follows:

[0062]

[0063] In the formula: A is the side surface area of ​​the variable phase energy storage panel under test, in m². 2 q(t) is the sum of the heat flux densities on both sides of the variable phase energy storage plate under test at a certain temperature, in W / m³. 2 m is the mass of the variable phase energy storage plate under test, kg; dt / dτ is the rate of temperature change with time, k / min.

[0064] The formula for calculating latent heat ΔH is as follows:

[0065]

[0066] In the formula: C p,ave t1 is the average specific heat capacity of the solid and liquid phases, J / kg·K; t1 is the phase transition initiation temperature, K; t2 is the phase transition termination temperature, K; t1 is determined from the specific heat capacity-temperature curve (i.e., Figure 3 The intersection of the tangent line at the point where the slope of the rising segment is maximum and the baseline; the value of t2 is the intersection of the tangent line at the point where the slope of the falling segment of the specific heat capacity-temperature curve is maximum and the baseline.

[0067] The formula for calculating thermal inertia is as follows:

[0068]

[0069] In the formula: a(t) is the thermal diffusivity at a certain temperature, i.e., thermal inertia, m 2 / s;λ ave ρ is the average thermal conductivity in the solid and liquid states, W / m·K; ρ is the density, kg / m³. 3 .

[0070] Furthermore, the thermal conductivity was tested, including:

[0071] S421. In the thermophysical performance test equipment, the two heat exchangers are kept at a constant temperature, and the temperature difference between the two heat exchangers is 5°C or more. The heat flux is observed until the fluctuation stops. The heat flux values ​​on both sides of the phase change energy storage plate under test are read respectively, and the thermal conductivity is calculated.

[0072] Specifically, the thermal conductivity test range in this embodiment is 10–15°C.

[0073] Set the water temperature of the left heat exchanger to 10℃ and the water temperature of the right heat exchanger to 15℃.

[0074] Maintain the temperature for 20 minutes until the heat flux data no longer fluctuates, and then read the heat flux data from both sides of the phase change energy storage plate under test.

[0075] The thermal conductivity λ of the phase change energy storage plate under test is calculated using the following formula:

[0076]

[0077] In the formula: λ is the thermal conductivity, W / m·K; q ave The average heat flux density across both sides of the specimen is W / m². 2 ;d represents the thickness of the phase change energy storage plate under test, in meters;t r The temperature on the right side of the phase change energy storage plate to be measured is kJ; t l The temperature on the left side of the phase change energy storage plate to be measured is in kJ.

[0078] Figure 3 The figure shows the test results of the specific heat capacity of the phase change energy storage plate and the constant property plate. The specific heat capacity of the constant property plate (MPCM0) changes with temperature as a horizontal straight line, while the specific heat capacity of the phase change energy storage plate (MPCM1-4) shows obvious peaks with temperature. This invention can effectively characterize the thermophysical properties of the phase change energy storage plate.

[0079] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0080] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thermophysical performance testing device for a phase change energy storage plate, characterized in that, include: Two measuring devices are connected by tie bolts (32) on the bracket, and the two measuring devices are placed symmetrically. The measuring device includes a variable constant temperature water circulation tank (1) and a testing unit. The variable constant temperature water circulation tank (1) is connected to the testing unit through a water pipe (13). The test unit includes a support pressure plate (31), an insulation box (21), a heat exchanger (22), a thermally conductive silicone pad (23), and a heat flux sensor (24), arranged sequentially from the inside to the outside. The bracket tie bolt (32) is mounted on the bracket pressure plate (31) by the bracket nut (33); pressure is applied by rotating the bracket nut (33).

2. The thermophysical performance testing equipment for a phase change energy storage plate according to claim 1, characterized in that, The variable constant temperature water circulation tank (1) is connected to the heat exchanger (22) through a water pipe (13).

3. The thermophysical performance testing equipment for a phase change energy storage plate according to claim 1, characterized in that, It also includes a data recording unit, which is connected to the heat flux sensor (24).

4. The thermophysical performance testing equipment for a phase change energy storage plate according to claim 1, characterized in that, A temperature control system (12) is installed on the variable constant temperature water circulation tank (1). The variable constant temperature water circulation tank (1) is equipped with a heater and a refrigeration compressor; The temperature control system (12) controls the operation of the heater or refrigeration compressor.

5. A method of using a thermophysical performance testing device for a phase change energy storage plate as described in any one of claims 1-4, characterized in that, Includes the following steps: After drying, the phase change energy storage panel under test is allowed to cool naturally to room temperature; The phase change energy storage plate to be tested is placed between two heat flux sensors of the thermophysical performance testing equipment for phase change energy storage plates. Rotate the support nut in the thermophysical performance testing equipment to apply pressure to the phase change energy storage plate under test; Turn on the variable constant temperature water circulation tank and data recording unit in the thermophysical performance testing equipment to test the phase change performance and thermal conductivity.

6. The method of using the thermophysical performance testing equipment for a phase change energy storage plate according to claim 5, characterized in that, The phase transition performance test includes: Set the initial temperature and target temperature; The initial temperature is kept constant for a certain period of time until the heat flux no longer fluctuates. Once the heat flux stabilizes, heat or cool at a constant rate of temperature change until the target temperature is reached. The heat flux and time data of the entire process are recorded by the data recording unit, and the phase change performance is calculated.

7. The method of using the thermophysical performance testing equipment for a phase change energy storage plate according to claim 6, characterized in that, The phase change properties include specific heat capacity, latent heat, and thermal inertia.

8. The method of using the thermophysical performance testing equipment for a phase change energy storage plate according to claim 5, characterized in that, The thermal conductivity test includes: The two heat exchangers in the thermophysical performance testing equipment are kept at a constant temperature, and there is a temperature difference between the two heat exchangers. The heat flux is observed until the fluctuation stops. The heat flux values ​​on both sides of the phase change energy storage plate under test are read, and the thermal conductivity is calculated.

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