Radiation refrigeration coating infrared temperature difference testing device and testing method

Abstract

The invention relates to the field of radiation refrigeration coating effect evaluation devices, in particular to an infrared temperature difference testing device for a radiation refrigeration coating. Comprising a control module, a detection bin assembly and an infrared imager, the detection bin assembly comprises a detection bin body, a heating plate and a temperature sensor; the working wave band of the infrared imager is 8-14 microns, and the infrared imager is used for detecting the surface infrared temperature of the detection plate or the calibration piece in the detection bin body through the detection hole; the control module can adjust the emissivity of the infrared imager to be the same as the emissivity of the calibration piece; when the detection plate is placed in, the control module controls the heating plate to heat, so that the temperature detected by one of the temperature sensor and the infrared imager reaches a set value, and the other detection temperature is obtained. According to the invention, the temperature difference effect caused by radiation cooling of the atmosphere window can be accurately measured.

Description

Technical Field

[0001] This application relates to the field of radiation cooling coating effect evaluation devices, and in particular to an infrared temperature difference testing device and testing method for radiation cooling coatings. Background Technology

[0002] Radiative cooling technology is a novel cooling technique where objects lower their temperature to below ambient temperature by emitting thermal radiation. This technology primarily utilizes the atmospheric radiation window between Earth and outer space, allowing thermal radiation from objects on Earth to pass through this window and directly radiate heat into outer space, thus achieving heat exchange with the colder environment of outer space. However, the resulting cooling or insulation benefits have not been effectively measured, making the evaluation of this effect a pressing issue for the industry.

[0003] Currently, the standard T / CIE 082-2020, "Test Method for Thermal Insulation Coatings," measures the temperature difference between the tested coating and a reference coating surface, both under specific heat source conditions, by measuring the temperature difference between the tested coating's surface near the heat source and the reference coating's surface near the heat source, as well as the temperature difference between the tested coating's back surface and the reference coating's back surface. The heat source used is water at 90±2℃.

[0004] CN111398340A discloses a method and system for measuring radiative cooling materials, which heats the radiative cooling material until its surface temperature matches the ambient temperature; a controller outputs a PWM signal based on the surface temperature and ambient temperature using a PID feedback algorithm to obtain the cooling power. CN120403920A discloses a radiative cooling power testing device and method that adjusts the heating power to make the material temperature match the ambient temperature, and calculates the cooling power based on the heating power.

[0005] The methods described above all rely solely on thermocouple temperature measurement. Temperature difference is a comprehensive property encompassing thermal conduction, convection, and infrared radiation. This inevitably leads to interference from the material's own thermal conduction, ambient air convection, and ambient light radiation, potentially misidentifying low thermal conductivity, high reflectivity materials as "radiative" materials. These methods also fail to effectively shield against ambient background radiation, resulting in measurement results including environmental reflection components and affecting the accuracy of emissivity calculations. Furthermore, they do not consider the uneven temperature distribution on the surface of the tested coating. Finally, they fail to optimize measurement parameters for the infrared atmospheric window band (8–14 μm), causing the measurement results to deviate from the actual requirements of radiation performance testing.

[0006] Infrared imagers receive the infrared radiation energy emitted by the target object through an optical imaging system (such as an optical objective lens) and focus it onto the photosensitive element of an infrared detector. They have good transmittance only in the mid-wave (3-5 μm) or long-wave (8-14 μm) bands; these are the wavelengths of light that can be "seen," meaning they respond within these bands. The core function of a thermal imager is to calculate temperature by detecting the infrared radiation energy emitted by an object. This calculation process requires knowledge of a key parameter—emissivity. Failure to change the emissivity parameter will lead to errors, and this error is precisely the temperature difference we need. The far-infrared band corresponds to the atmospheric window of 8-14 μm, which is also the emissivity of the band we need to measure. It offers high spatial resolution, measuring 200,000 points per second, making it suitable for measuring temperature fields such as coatings, increasing the accuracy of the test.

[0007] There is a lack of precise cooling devices for measuring coatings with an 8-14μm atmospheric window. Infrared imaging utilizes the 8-14μm band. If the two are combined, the temperature difference caused by the material's emissivity can be measured as the cooling temperature difference, making the test simple, fast, and accurate. Summary of the Invention

[0008] In view of this, this application provides an infrared temperature difference testing device and method for radiation cooling coatings, which can accurately measure the temperature difference effect caused by radiation cooling of atmospheric windows.

[0009] To achieve the above objectives, this application employs the following technical solution:

[0010] An infrared temperature difference testing device for radiation-cooled coatings, characterized in that it includes a control module, a detection chamber assembly, and an infrared imager disposed outside the detection chamber assembly; the detection chamber assembly includes a detection chamber body and a heating plate and a temperature sensor disposed inside the detection chamber body; the heating plate is used to place and heat the detection plate or calibration piece, and the temperature sensor is used to detect the surface temperature of the detection plate or calibration piece; the detection chamber body is provided with a detection hole, and the infrared imager operates in the 8-14μm band, and the infrared imager detects the surface infrared temperature of the detection plate or calibration piece inside the detection chamber body through the detection hole; the control module is connected to the infrared imager and the temperature sensor respectively to obtain the temperature values ​​detected by each, and the control module can adjust the emissivity of the infrared imager to the emissivity of the calibration piece; the control module is connected to the heating plate to control its heating temperature, and when the control module controls the heating plate to heat the detection plate placed inside the detection chamber to a set value, the control module can simultaneously record the temperature value detected by the other of the temperature sensor and the infrared imager.

[0011] The aforementioned infrared temperature difference testing device for a radiation-cooled coating utilizes the characteristics of an infrared imager to collect infrared heat emission in the 8-14μm band of an atmospheric window, avoiding the influence of heat convection, heat conduction, and ambient light sources. By controlling the temperature of the calibration piece and the test plate to be consistent (ensuring consistent temperature measurements by the temperature sensors), the temperature difference between the test plate temperature measured by infrared imaging and the temperature of the calibration piece is calculated. Alternatively, the infrared imaging temperatures of the test plate and the calibration piece can be unified to test the temperature difference of the temperature sensors. This allows for an accurate comparison of the cooling effect brought about by actual "radiation." This device provides rapid and accurate detection, precisely measuring the temperature difference effect caused by radiative cooling of the atmospheric window.

[0012] The infrared imager can be an uncooled long-wave infrared thermal imager with a working wavelength of 8–14 μm, a frame pixel of 640×480 or higher, a frame rate of 25 Hz, an integration time of 10 ms, and an output mode of infrared radiation brightness and the average temperature of the entire board.

[0013] In some embodiments, the inner wall of the detection chamber is coated with a black paint with an absorptivity greater than 0.95 to create a near-blackbody environment.

[0014] In some embodiments, the temperature sensor is a thermocouple sensor, and a magnetic block is provided in the middle of the heating plate, so that the thermocouple sensor is fixed to the detection plate by magnetic attraction. This structure makes the thermocouple sensor easy to install and remove.

[0015] In some embodiments, the detection chamber is further equipped with an angle adjustment device, and the heating plate is mounted on the angle adjustment device. The angle adjustment device is used to adjust the angle between the normal of the coating surface of the detection plate and the optical axis of the infrared imager. By adding an angle adjustment device, detection plates of different thicknesses can be accommodated, thus improving the applicability and flexibility of the device.

[0016] In some embodiments, the testing chamber is provided with an openable door for taking out and placing the testing plate, the door is provided with a handle, and the testing chamber is provided with an insulation layer.

[0017] In some embodiments, a display module is also included, and the control module is connected to the display module. The temperature detected by the infrared imager and the temperature sensor is displayed on the display module through the control module.

[0018] In some implementations, the calibration element is a blackbody radiation source or a standard plate.

[0019] The radiation source can be a surface blackbody with an emissivity >0.99, a temperature control range of 20–150℃, and a temperature stability of ±0.1℃.

[0020] The standard plate can be made of any emissivity-stable material, such as polished aluminum plate (0.15), copper mirror (0.05), gold mirror (0.02), nickel-chromium alloy (0.70), etc.

[0021] In some implementations, to ensure uniform heating of the heating plate, a rectangular induction coil is selected as the heating plate. The number of coil turns is adjusted to control the magnetic field strength and distribution, so that the eddy currents generated in each part of the metal sheet are uniform, thereby achieving uniform heating.

[0022] In some implementations, to ensure more accurate data, the device is tested in a constant-temperature environment. This environment temperature is fixed at a single value to reduce measurement errors, and the temperature parameter is input into the infrared thermal imager. Moisture and dust can attenuate infrared signals, so the detection chamber is designed to maintain humidity below 85% and a dust-free environment for measurement.

[0023] This application also provides a method for testing the infrared temperature difference of a radiation-cooled coating, characterized by comprising the following steps:

[0024] ① Adjust the emissivity of the infrared imager to the emissivity of the calibration piece, place the calibration piece into the detection chamber and place it on the heating plate, heat the heating plate to make the temperature Ta1 of the calibration piece measured by the infrared imager consistent with the temperature Ta2 of the calibration piece measured by the temperature sensor;

[0025] ②The emissivity of the infrared imager remains constant. The detection plate is placed on the heating plate, the heating plate is heated, the temperature sensor measures the temperature of the detection plate as Ta2, and the infrared imager records the temperature Tb at this moment.

[0026] ③ Calculate the temperature difference between Tb and Ta2.

[0027] In this measurement method, the higher the emissivity of the calibration plate, the higher the infrared imaging temperature will be. This is because a higher emissivity indicates stronger atmospheric window radiation, resulting in a higher infrared capture temperature.

[0028] This application also provides another method for testing the infrared temperature difference of a radiation-cooled coating, characterized by the following steps:

[0029] ① Adjust the emissivity of the infrared imager to the emissivity of the calibration piece, place the calibration piece into the detection chamber and place it on the heating plate, heat the heating plate to make the temperature Ta1 of the calibration piece measured by the infrared imager consistent with the temperature Ta2 of the calibration piece measured by the temperature sensor;

[0030] ②The emissivity of the infrared imager remains constant. The detection plate is placed on the heating plate, which heats up. The infrared imager measures the temperature of the detection plate as Ta1, and the temperature sensor records the temperature Tb at this moment.

[0031] ③ Calculate the temperature difference between Tb and Ta1.

[0032] In this method, the higher the emissivity of the calibration plate, the lower the thermocouple temperature. This is because higher emissivity results in stronger atmospheric window radiation and a more significant cooling effect on the surface.

[0033] As can be seen from the above technical solution, this application has at least the following advantages and positive effects:

[0034] 1. By fixing the ambient temperature (thermocouple), the radiative temperature difference caused by different emissivity (with calibration components) can reflect its radiation and cooling capabilities. The temperature evaluation method is simpler and more intuitive, and can be used to evaluate the cooling effect of radiative cooling materials. The device has a simple and convenient structure.

[0035] 2. High-precision surface measurement: Through the area array detection of the infrared imager, large-area, high-resolution measurement of the emissivity of the coating surface is achieved, with a measurement resolution of up to 0.1mm×0.1mm.

[0036] 3. Strong environmental adaptability: The enclosed measurement cavity design effectively shields against environmental background radiation and reflection. Combined with a blackbody radiation source, it eliminates environmental interference and improves measurement accuracy.

[0037] 4. Adaptive temperature field correction: Based on multi-frame infrared image data, the surface temperature of the coating is more accurate, avoiding measurement errors caused by uneven temperature.

[0038] 5. Atmospheric window band optimization: The temperature measured by infrared imaging in the 8-14μm infrared atmospheric window band is highly matched with the application of radiative cooling efficiency in the atmospheric window band. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of an embodiment of this application;

[0040] Figure 2 This is a screenshot of the detection screen in an embodiment of this application. Figure 1 ;

[0041] Figure 3 This is a screenshot of the detection screen in an embodiment of this application. Figure 2 .

[0042] Labeling Explanation: 1. Infrared Imager; 2. Detection Chamber; 21. Movable Door; 22. Handle; 23. Insulation Layer; 3. Heating Plate; 4. Temperature Sensor; 5. Detection Plate. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the application will be described in further detail below with reference to the accompanying drawings. The terminology used in the embodiments section of this application is only for explaining specific embodiments and is not intended to limit the application.

[0044] Example 1: See Figures 1 to 3 This embodiment provides an infrared temperature difference testing device for radiation-cooled coatings, including a control module, a detection chamber assembly, and an infrared imager 1 disposed outside the detection chamber assembly. The detection chamber assembly includes a detection chamber body 2 and a heating plate 3 and a temperature sensor 4 disposed inside the detection chamber body 2. The heating plate 3 is used to place and heat the detection plate 5 or calibration piece, and the temperature sensor 4 is used to detect the surface temperature of the detection plate 5 or calibration piece. A detection hole is provided on the detection chamber body 2, and the infrared imager 1 operates in the 8-14 μm band, using the infrared imager 1 to detect the detection chamber body through the detection hole. 2. Detect the surface infrared temperature of the inner detection plate 5 or calibration piece; the control module is connected to the infrared imager 1 and the temperature sensor 4 respectively to obtain the temperature values ​​detected by each, and the control module can adjust the emissivity of the infrared imager 1 to the emissivity of the calibration piece; the control module is connected to the heating plate 3 to control its heating temperature, and when the control module controls the heating plate 3 to heat the temperature of the detection plate 5 placed in the detection chamber 2 so that the temperature value detected by one of the temperature sensor 4 and the infrared imager 1 reaches the set value, the control module can simultaneously record the temperature value detected by the other of the temperature sensor 4 and the infrared imager 1.

[0045] This infrared temperature difference testing device for radiation-cooled coatings utilizes the characteristics of infrared imager 1 to collect infrared heat emission in the 8-14μm band of the atmospheric window, avoiding the influence of heat convection, heat conduction, and ambient light sources. By controlling the temperature of the calibration piece and the test plate 5 to be consistent (the temperature measured by temperature sensor 4 to be consistent), the temperature difference between the test plate 5 measured by infrared imaging and the calibration piece is calculated. Alternatively, the infrared imaging temperatures of the test plate 5 and the calibration piece can be unified to test the temperature difference of temperature sensor 4. This allows for an accurate comparison of the cooling effect brought about by actual "radiation." This device provides rapid and accurate detection, precisely measuring the temperature difference effect caused by radiative cooling of the atmospheric window.

[0046] The infrared imager 1 can be an uncooled long-wave infrared thermal imager with a working wavelength of 8-14μm, a frame pixel of 640×480 or higher, a frame rate of 25Hz, an integration time of 10ms, and an output mode of infrared radiation brightness and the average temperature of the entire panel.

[0047] The inner wall of the detection chamber 2 is coated with a black paint with an absorption rate greater than 0.95 to form a near-blackbody environment.

[0048] The temperature sensor 4 is a thermocouple sensor, and a magnetic block is provided in the middle of the heating plate 3. The thermocouple sensor is fixed to the detection plate 5 by magnetic attraction. This structure makes the thermocouple sensor easy to install and remove.

[0049] The detection chamber 2 is also equipped with an angle adjustment device, and the heating plate 3 is mounted on the angle adjustment device. The angle adjustment device is used to adjust the angle between the normal of the coating surface of the detection plate 5 and the optical axis of the infrared imager 1. By adding the angle adjustment device, detection plates 5 of different thicknesses can be accommodated, thus improving the applicability and flexibility of the device.

[0050] The testing chamber is equipped with an openable door 21 for taking out and putting in the testing plate 5. The door 21 is equipped with a handle 22. The testing chamber body 2 is equipped with an insulation layer 23.

[0051] It also includes a display module, and the control module is connected to the display module. The temperatures detected by the infrared imager 1 and the temperature sensor 4 are displayed on the display module through the control module.

[0052] The calibration component is a blackbody radiation source or a standard plate.

[0053] The radiation source can be a surface blackbody with an emissivity >0.99, a temperature control range of 20–150℃, and a temperature stability of ±0.1℃.

[0054] The standard plate can be made of any emissivity-stable material, such as polished aluminum plate (0.15), copper mirror (0.05), gold mirror (0.02), nickel-chromium alloy (0.70), etc.

[0055] To ensure uniform heating of the heating plate 3, a rectangular induction coil is selected for the heating plate 3. The number of coil turns is adjusted to control the magnetic field strength and distribution, so that the eddy currents generated in each part of the metal sheet are uniform, thereby achieving uniform heating.

[0056] To ensure more accurate data, the equipment is tested in a constant-temperature environment. This environment is kept at a fixed temperature to reduce measurement errors. This temperature parameter is input into the infrared thermal imager. Moisture and dust can attenuate infrared signals, so the detection chamber is designed to maintain humidity below 85% and a dust-free environment for measurement.

[0057] Example 2: A method for measuring the radiative temperature difference of a common white coating (latex paint)

[0058] 1. Device initialization:

[0059] The FLIR A655sc long-wave infrared thermal imager was selected, with a working wavelength of 8–14 μm, a frame resolution of 640×480 pixels, and a frame rate of 25 Hz.

[0060] A closed measurement chamber was constructed, with the inner wall coated with Nextel Velvet Coating 811-21 black paint, with an absorption rate >0.97.

[0061] The Mikron M360 surface source blackbody was selected, with an emissivity >0.995 and a temperature control range of 20–150℃.

[0062] 2. Environmental radiation calibration:

[0063] The temperature was increased to the blackbody temperature Ta1 = 50.00℃, a blackbody radiation image was acquired, and Ta2 = 50.00℃ was recorded.

[0064] 3. Coating surface temperature measurement:

[0065] A latex paint coating sample (composed of acrylic emulsion, heavy calcium carbonate, titanium dioxide, and other fillers) with a thickness of 300 μm was placed on the plate, and the angle θ was adjusted to 0°. The heating device was adjusted, and the temperature was raised to 50°C as indicated by the thermocouple display on the plate surface. The infrared imager measured the temperature at 48.53°C.

[0066] Example 3: A method for measuring the radiative temperature difference of a reflective heat-insulating coating

[0067] 1. Device initialization:

[0068] The FLIR A655sc long-wave infrared thermal imager was selected, with a working wavelength of 8–14 μm, a frame resolution of 640×480 pixels, and a frame rate of 25 Hz.

[0069] A closed measurement chamber was constructed, with the inner wall coated with Nextel Velvet Coating 811-21 black paint, with an absorption rate >0.97.

[0070] The Mikron M360 surface source blackbody was selected, with an emissivity >0.995 and a temperature control range of 20–150℃.

[0071] 2. Environmental radiation calibration:

[0072] The temperature was increased to the blackbody temperature Ta1 = 50.00℃, a blackbody radiation image was acquired, and Ta2 = 50.00℃ was recorded.

[0073] 3. Coating surface temperature measurement:

[0074] A sample of reflective heat-insulating coating (composed of acrylic emulsion, reflective titanium dioxide, and other fillers) with a thickness of 300 μm was placed on the plate, and the angle θ = 0° was adjusted. The heating device was adjusted to raise the temperature until the thermocouple reading on the plate surface showed 50°C. The infrared imager measured the temperature at 48.78°C.

[0075] Example 4: A method for measuring the radiative temperature difference of a radiative cooling coating.

[0076] 1. Device initialization:

[0077] The FLIR A655sc long-wave infrared thermal imager was selected, with a working wavelength of 8–14 μm, a frame resolution of 640×480 pixels, and a frame rate of 25 Hz.

[0078] A closed measurement chamber was constructed, with the inner wall coated with Nextel Velvet Coating 811-21 black paint, with an absorption rate >0.97.

[0079] The Mikron M360 surface source blackbody was selected, with an emissivity >0.995 and a temperature control range of 20–150℃.

[0080] 2. Environmental radiation calibration:

[0081] The temperature was increased to the blackbody temperature Ta1 = 50.00℃, a blackbody radiation image was acquired, and Ta2 = 50.00℃ was recorded.

[0082] 3. Coating surface temperature measurement:

[0083] A sample of reflective heat-insulating coating (composed of acrylic emulsion, radiation fillers, etc.) with a thickness of 300 μm was placed on the plate, and the angle θ = 0° was adjusted. The heating device was adjusted to raise the temperature until the thermocouple temperature display on the plate surface showed 50°C. The infrared imager measured the temperature at 49.67°C.

[0084] Example 5: A method for measuring the radiative temperature difference of a radiative cooling coating (low-emission control panel)

[0085] 1. Device initialization:

[0086] The FLIR A655sc long-wave infrared thermal imager was selected, with a working wavelength of 8–14 μm, a frame resolution of 640×480 pixels, and a frame rate of 25 Hz.

[0087] A closed measurement chamber was constructed, with the inner wall coated with Nextel Velvet Coating 811-21 black paint, with an absorption rate >0.97.

[0088] The standard plate is made of low emissivity material, polished aluminum, and its emissivity calibration (Fourier transform infrared integrating sphere calibration) is 0.15.

[0089] 2. Standard plate calibration:

[0090] Heat the standard plate to a temperature of Ta1 = 50.00℃, adjust the infrared emissivity index to 0.15, acquire the radiation image of the standard plate, and record Ta2 = 50.00℃.

[0091] 2. Coating surface temperature measurement:

[0092] A sample of reflective heat-insulating coating (composed of acrylic emulsion, radiation fillers, etc.) with a thickness of 300 μm was placed on the plate, and the angle θ = 0° was adjusted. The heating device was adjusted to raise the temperature until the thermocouple display on the plate showed 50°C. The infrared imager measured the temperature at 57.83°C.

[0093] Example 6: Method for Measuring the Radiation Temperature Difference of a Common White Paint (Low Emission Comparison Panel)

[0094] 1. Device initialization:

[0095] The FLIR A655sc long-wave infrared thermal imager was selected, with a working wavelength of 8–14 μm, a frame resolution of 640×480 pixels, and a frame rate of 25 Hz.

[0096] A closed measurement chamber was constructed, with the inner wall coated with Nextel Velvet Coating 811-21 black paint, with an absorption rate >0.97.

[0097] The standard plate is made of low emissivity material, polished aluminum, and its emissivity calibration (Fourier transform infrared integrating sphere calibration) is 0.15.

[0098] 2. Standard plate calibration:

[0099] Heat the standard plate to a temperature of Ta1 = 50.00℃, adjust the infrared emissivity index to 0.15, acquire the radiation image of the standard plate, and record Ta2 = 50.00℃.

[0100] 3. Coating surface temperature measurement:

[0101] A sample of reflective heat-insulating coating (composed of acrylic emulsion, radiation fillers, etc.) with a thickness of 300 μm was placed on the plate, and the angle θ = 0° was adjusted. The heating device was adjusted to raise the temperature until the thermocouple temperature display on the plate surface showed 50°C. The infrared imager measured the temperature at 55.91°C.

[0102] Example 7: A method for measuring the radiative cooling temperature difference (fixed infrared temperature, testing the thermocouple temperature difference)

[0103] 1. Device initialization:

[0104] The FLIR A655sc long-wave infrared thermal imager was selected, with a working wavelength of 8–14 μm, a frame resolution of 640×480 pixels, and a frame rate of 25 Hz.

[0105] A closed measurement chamber was constructed, with the inner wall coated with Nextel Velvet Coating 811-21 black paint, with an absorption rate >0.97.

[0106] The standard plate selected is made of low-emissivity polished aluminum, with an emissivity calibration (Fourier transform infrared integrating sphere) of 0.15.

[0107] 2. Standard plate calibration:

[0108] Heat the standard plate to a temperature of Ta1 = 50.00℃, adjust the infrared emissivity index to 0.15, acquire the radiation image of the standard plate, and record Ta2 = 50.00℃.

[0109] 3. Coating surface temperature measurement:

[0110] A radiation-cooled coating sample (composed of acrylic emulsion, radiation filler, etc.) with a thickness of 300 μm was placed, and the angle θ = 0° was adjusted. The heating device was adjusted, and the temperature of the plate surface was raised to 50.00℃ as measured by the infrared imager, while the thermocouple temperature reading was 42.06℃.

[0111] Comparative Examples 2-4 all used a high-emissivity blackbody material as the standard plate. The measured temperature differences were: ordinary coating: 1.47℃, reflective heat insulation coating: 1.22℃, and radiative cooling coating: 0.33℃. Analysis showed that the radiative cooling coating was closer to a blackbody. Since the comparison plate was a high-emissivity material, the lower the temperature difference, the stronger the radiation capability.

[0112] Comparative Examples 5-6, where 4 and 5 are low-emissivity polished aluminum plates used as standard plates, show temperature differences of 5.91℃ for ordinary coating and 7.83℃ for radiation-cooled coating, respectively. The temperature difference is larger than that of the blackbody comparison plate; a larger temperature difference indicates stronger radiation capability. Comparative Examples 2-6 all use uniform thermocouple temperatures and measure infrared temperature differences. For radiating materials, the infrared measured temperature does not "cool down" but rather increases; in reality, the high-emissivity material is "seen" at a higher temperature by infrared imaging. Comparative Example 6 uses uniform infrared imager temperatures for both the standard plate and the test plate, and measures the thermocouple temperature. Using the polished aluminum plate as a comparison plate, a significant cooling effect is observed, with radiation cooling reaching 7.94℃.

[0113] To verify whether the temperature difference is caused by the emissivity of the atmospheric window, emissivity inversion was performed on the material.

[0114] In Comparative Example 7, the atmospheric window emissivity of the radiation-cooling coating was measured to be 0.93 using a Fourier integrating sphere.

[0115] The standard plate was selected as a low emissivity material, which was polished aluminum. Its emissivity calibration (Fourier transform infrared integrating sphere) was 0.15. The plate was heated to a temperature of Ta1 = 50.00℃, and the infrared emissivity index was adjusted to 0.15. The radiation image of the standard plate was acquired and recorded as Ta2 = 50.00℃.

[0116] Coating surface temperature measurement: A radiation-cooled coating sample (composed of acrylic emulsion, radiation filler, etc.) with a thickness of 300 μm was placed, and the angle θ = 0° was adjusted. The emissivity was adjusted to 0.93, and the heating device was adjusted to raise the temperature to 50.00°C as measured by an infrared imager. The thermocouple temperature was measured at 49.98°C. It can be seen that there is almost no temperature difference, while the temperature difference of 7.94°C in the original Example 6 was caused by emissivity. This detection method can accurately measure the temperature difference caused by the emissivity of the atmospheric window.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of this application, and are not intended to limit them; although the embodiments of this application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An infrared temperature difference testing device for a radiation-cooled coating, characterized in that: The system includes a control module, a detection chamber assembly, and an infrared imager (1) disposed outside the detection chamber assembly. The detection chamber assembly includes a detection chamber body (2) and a heating plate (3) and a temperature sensor (4) disposed inside the detection chamber body (2). The heating plate (3) is used to place the detection plate (5) or calibration piece and heat it. The temperature sensor (4) is used to detect the surface temperature of the detection plate (5) or calibration piece. The detection chamber body (2) is provided with a detection hole. The infrared imager (1) operates in the wavelength range of 8 to 14 μm. The infrared imager (1) uses the detection hole to detect the detection plate (5) or calibration piece inside the detection chamber body (2). The surface infrared temperature of the component; the control module is connected to the infrared imager (1) and the temperature sensor (4) respectively to obtain the temperature values ​​detected by each, and the control module can adjust the emissivity of the infrared imager (1) to the emissivity of the calibration component; the control module is connected to the heating plate (3) to control its heating temperature, and when the control module controls the heating plate (3) to heat the temperature of the detection plate (5) placed in the detection chamber (2) so that the temperature value detected by one of the temperature sensor (4) and the infrared imager (1) reaches the set value, the control module can simultaneously record the temperature value detected by the other of the temperature sensor (4) and the infrared imager (1).

2. The infrared temperature difference testing device for radiation-cooled coatings according to claim 1, characterized in that: The inner wall of the detection chamber (2) is coated with a black paint with an absorption rate greater than 0.95 to form a near-blackbody environment.

3. The infrared temperature difference testing device for radiation-cooled coatings according to claim 1, characterized in that: The temperature sensor (4) is a thermocouple sensor. A magnetic block is provided in the middle of the heating plate (3). The thermocouple sensor is fixed on the detection plate (5) by magnetic attraction.

4. The infrared temperature difference testing device for radiation-cooled coatings according to claim 1, characterized in that: An angle adjustment device is also provided inside the detection chamber (2). The heating plate (3) is installed on the angle adjustment device. The angle adjustment device is used to adjust the angle between the normal of the coating surface of the detection plate (5) and the optical axis of the infrared imager (1).

5. The infrared temperature difference testing device for radiation-cooled coatings according to claim 1, characterized in that: The testing chamber is equipped with an openable door (21) for taking out and putting in the testing plate (5). The door (21) is equipped with a handle (22). The testing chamber body (2) is equipped with an insulation layer (23).

6. The infrared temperature difference testing device for radiation-cooled coatings according to claim 1, characterized in that: It also includes a display module, and the control module is connected to the display module. The temperature detected by the infrared imager (1) and the temperature sensor (4) is displayed on the display module through the control module.

7. The infrared temperature difference testing device for radiation-cooled coatings according to claim 1, characterized in that: The calibration component is a blackbody radiation source or a standard plate.

8. A method for testing the infrared temperature difference of a radiation-cooled coating, characterized in that: Includes the following steps: ① Adjust the emissivity of the infrared imager (1) to the emissivity of the calibration piece, place the calibration piece in the detection chamber (2) and place it on the heating plate (3), and heat the heating plate (3) so that the temperature Ta1 of the calibration piece measured by the infrared imager (1) is consistent with the temperature Ta2 of the calibration piece measured by the temperature sensor (4); ② The emissivity of the infrared imager (1) remains unchanged. It is placed on the detection plate (5) and placed on the heating plate (3). The heating plate (3) is heated. The temperature sensor (4) measures the temperature of the detection plate (5) as Ta2. The infrared imager (1) records the temperature Tb at this moment. ③ Calculate the temperature difference between Tb and Ta2.

9. A method for testing the infrared temperature difference of a radiation-cooled coating, characterized in that: Includes the following steps: ① Adjust the emissivity of the infrared imager (1) to the emissivity of the calibration piece, place the calibration piece in the detection chamber (2) and place it on the heating plate (3), and heat the heating plate (3) so that the temperature Ta1 of the calibration piece measured by the infrared imager (1) is consistent with the temperature Ta2 of the calibration piece measured by the temperature sensor (4); ② The emissivity of the infrared imager (1) remains unchanged. It is placed on the detection plate (5) and placed on the heating plate (3). The heating plate (3) is heated. The infrared imager (1) measures the temperature of the detection plate (5) as Ta1. The temperature sensor (4) records the temperature Tb at this moment. ③ Calculate the temperature difference between Tb and Ta1.

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