All-weather light-following automatic testing device for photo-thermal conversion rate of phase change heat storage material

Abstract

The invention discloses an all-weather light-following automatic testing device for the photo-thermal conversion rate of a phase-change heat storage material, and aims to solve the problems of insufficient authenticity, limited testing size and complex data processing in the measurement of the photo-thermal conversion rate of the phase-change heat storage material. By designing a light following control unit, a photo-thermal conversion storage unit and a data acquisition and processing unit, the integrated photo-thermal conversion rate testing device is built. The device truly simulates illumination conditions and environmental change factors of the phase change heat storage material in actual work, ensures authenticity of test results, considers test requirements of samples with different sizes, realizes adjustability of irradiation light spots along with the sizes of the samples, simplifies a data processing flow, and automatically outputs a photo-thermal conversion rate result. The device is simple in structure and convenient to operate, and has certain engineering application potential.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of phase change heat storage, and relates to a phase change heat storage material light-heat conversion rate automatic testing device capable of all-weather light tracking. BACKGROUND

[0002] Phase change heat storage materials are important components in the field of thermal energy storage and utilization due to their high heat storage density and stability. Especially in the process of solar thermal energy conversion and storage, phase change heat storage materials can effectively improve the efficiency and stability of solar energy utilization. Among them, the light-heat conversion rate of phase change heat storage materials is an important performance indicator for measuring the conversion of solar energy into heat energy. Therefore, accurately and efficiently measuring the light-heat conversion rate has important guiding significance for optimizing the performance of phase change heat storage materials and promoting practical engineering applications.

[0003] The existing measurement devices for the light-heat conversion rate of phase change heat storage materials mostly use artificial light sources such as solar simulators, xenon lamps, and halogen lamps. By simulating indoor irradiation conditions, the temperature change curve of phase change heat storage materials under light is measured, and the light-heat conversion rate is obtained by formula conversion However, this testing method based on artificial light sources has limitations such as: (1) Since the testing device is located indoors, it is difficult to simulate real all-weather changes in the actual working environment, such as outdoor temperature fluctuations, wind speed changes (enhanced convective heat transfer under high wind speed conditions), weather conditions (changes in sunny and cloudy conditions), and dynamic changes in the intensity of full-sunlight irradiation, for example, the solar irradiation intensity at 12:00 noon is about 6 times that at 16:00 in the evening, resulting in a large deviation between the test results and the actual application scenario; (2) Limited by the effective irradiation area of artificial light sources, current testing devices are usually only suitable for small-sized (about 1-50mm) phase change heat storage material samples, and there are difficulties in testing large-sized phase change heat storage material samples. In addition, high-power artificial light sources are expensive, and their cost is proportional to the effective irradiation area, further increasing the cost of testing large-sized samples (more than 50mm).

[0004] In terms of testing procedures, the current testing method can usually only record the temperature change curve of phase change heat storage materials over time, but cannot directly output the actual heat absorbed, resulting in the need for additional data conversion when obtaining the light-heat conversion rate. This not only increases the difficulty of data processing, but also may introduce experimental errors, reducing the efficiency and accuracy of the test. Therefore, developing a measurement device that can accurately measure the light-heat conversion rate of phase change heat storage materials under natural light conditions, suitable for various sizes of samples, and with low cost and simple data processing, has become one of the technical problems to be solved in the practical engineering application of heat storage materials. SUMMARY

[0005] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide an all-weather light-chasing phase change heat storage material light-heat conversion rate automatic testing device, which aims at the problems of insufficient authenticity, limited test size and complex data processing in the prior art of using artificial light source to measure the light-heat conversion rate of phase change heat storage material. By designing a light-chasing control unit, a light-heat conversion storage unit and a data acquisition and processing unit, an integrated light-heat conversion rate testing device is built to realize the testing and evaluation of phase change heat storage material under real conditions.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0007] An all-weather light-chasing phase change heat storage material light-heat conversion rate automatic testing device, comprising:

[0008] A light-chasing control unit for automatic all-weather light-chasing outdoors, which adopts a frame structure with a Fresnel lens installed on the top of the frame structure;

[0009] A light-heat conversion storage unit for placing the sample to be tested and keeping warm, comprising a sample bin with a heat insulation protective sleeve, the sample bin is configured to be arranged in the frame structure and can move along the column direction of the frame structure, and is always located below the Fresnel lens;

[0010] A data acquisition and processing unit for real-time automatic data acquisition, transmission and processing, comprising a temperature sensor, an outdoor temperature acquisition device, a light power meter, a wind speed and direction instrument and a data processor, wherein the number of temperature sensors is multiple and is arranged at different height positions of the sample bin.

[0011] In one embodiment, the column direction of the frame structure is provided with a focal length adjustment track, and the sample bin is directly or indirectly arranged in the focal length adjustment track to move along the column direction on the focal length adjustment track to adjust the distance from the Fresnel lens.

[0012] In one embodiment, the Fresnel lens is parallel to the cross section of the sample bin to ensure that sunlight is accurately projected to the center position of the sample bin; the stroke of the focal length adjustment track is 0-1m, the distance between the sample bin and the Fresnel lens is adjusted to control the size of the light spot, and the size range of the light spot is 5-150mm.

[0013] In one embodiment, a precision light-chasing device is installed on the frame structure, the bottom of the frame structure is connected to a support column through a horizontal rotating shaft, the support column is connected to the frame structure through a driving screw arranged along the column direction, and the horizontal rotating shaft is perpendicular to the column direction.

[0014] In one embodiment, the precision light tracker is installed at the same horizontal position as the sample chamber, and the photoelectric sensor element built in the precision light tracker converts the light intensity into an electrical signal to control the start and stop of the motor driving the screw rod and the rotation of the shaft, thereby controlling the pitch angle and orientation of the device so that the plane of the Fresnel lens always faces the sunlight. The present application uses the precision light tracker in cooperation with the driving screw rod to accurately and real-time track the position of the sun, automatically adjust the angle of incidence of sunlight, and ensure that the light is always perpendicular to the sample surface, thereby achieving all-weather tracking.

[0015] In one embodiment, the photo-thermal conversion storage unit further comprises a sample placement platform.

[0016] The sample placement platform is installed in the frame structure, and the sample chamber is installed on the sample placement platform. The sample chamber is made of high-temperature-resistant stainless steel and has a sample lining frame inside, with a size range of 10-100 mm, for accommodating different sizes of phase change heat storage materials. An external heat insulation protective sleeve is provided to prevent heat loss to the environment and leakage of the phase change heat storage material.

[0017] In one embodiment, the working temperature of the temperature sensor is -30℃-1200℃.

[0018] In one embodiment, the data processor collects the data collected by the temperature sensor, the outdoor temperature acquisition device, the optical power meter and the anemometer, and automatically calculates and displays the photo-thermal conversion rate of the phase change heat storage material in real time.

[0019] The present application also provides an automatic testing method for the all-weather light tracking photo-thermal conversion rate automatic testing device for phase change heat storage materials, comprising the following steps:

[0020] Place the sample to be tested into the sample chamber, and adjust the distance between the sample to be tested in the sample chamber and the Fresnel lens so that the sample is within the focal length range of the Fresnel lens.

[0021] Start the precision light tracker to automatically track the position of the sun, and adjust the lens angle by the driving screw rod so that the sunlight is always perpendicular to the surface of the sample to be tested.

[0022] The optical power meter measures and records the solar irradiance P in real time, the temperature sensor collects the internal temperature change ΔT of the sample in real time, the anemometer and the outdoor temperature acquisition device record the environmental changes, and all the data are sent to the data processor. According to the formula The photo-thermal conversion rate η in time t is calculated.

[0023] In one embodiment, the internal temperature change ΔT is collected by the following method:

[0024] The temperature sensors at different height positions collect the internal temperature of the sample bin in real time, and the internal temperature change ΔT is obtained by averaging the values by the data processor.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] 1. The present application provides a full-weather test device for testing the photo-thermal conversion rate of phase change heat storage materials suitable for outdoor environments, which truly simulates key factors such as outdoor temperature changes, wind speed and direction fluctuations, weather condition changes, and dynamic changes in full-day sunlight intensity of phase change heat storage materials in actual working environments, solves the limitation that indoor test devices cannot truly reflect actual application conditions, and ensures the accuracy and authenticity of test results.

[0027] 2. Through the cooperative matching of the precision light tracker, the Fresnel lens, and the focal length adjustment track, the sun position can be tracked in real time and accurately, and the sunlight incidence angle and the size of the condensing spot can be dynamically adjusted, which expands the testable size of the sample; through the integrated data acquisition and real-time processing system, automatic acquisition and real-time synchronous processing of multiple parameters such as temperature, light power, wind speed, and wind direction are realized, the photo-thermal conversion rate of phase change heat storage materials is automatically calculated, and the test efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a front view of the automatic test device for the photo-thermal conversion rate of phase change heat storage materials.

[0029] Figure 2 It is a left view of the automatic test device for the photo-thermal conversion rate of phase change heat storage materials.

[0030] Figure 3 It is a structure schematic diagram of the sample bin of the automatic test device for the photo-thermal conversion rate of phase change heat storage materials.

[0031] Figure 4 It is a structure schematic diagram of the precision light tracker, the driving screw, and the rotating shaft of the automatic test device for the photo-thermal conversion rate of phase change heat storage materials.

[0032] Figure 5 It is a test schematic diagram of the automatic test device for the photo-thermal conversion rate of phase change heat storage materials.

[0033] Figure 6 It is an example of test results of the photo-thermal conversion rate of stearic acid-carbon composite phase change heat storage materials.

[0034] Label name in the figure: 1-Fresnel lens, 2-light power meter, 3-focal length adjustment track, 4-precision light tracker, 5-driving screw, 6-data processor, 7-sample bin placement platform, 8-outdoor temperature acquisition device, 9-wind speed and direction instrument, 10-sample bin, 11-heat insulation protective sleeve, 12-temperature sensor. DETAILED DESCRIPTION

[0035] For more clearly set forth the purpose, method and advantages of the present application, the present application is further described in conjunction with the drawings.

[0036] In view of the problems of authenticity deficiency, limited test size and complex data processing in the prior art of using artificial light source to measure the photo-thermal conversion rate of phase change thermal storage material, the present application provides an automatic testing device for photo-thermal conversion rate of phase change thermal storage material under all-weather light tracking.

[0037] As shown in Figure 1 , Figure 2 , Figure 3 and Figure 4 , the device mainly comprises a light tracking control unit, a photo-thermal conversion storage unit and a data acquisition and processing unit.

[0038] The light tracking control unit mainly consists of a Fresnel lens 1, a focal length adjustment track 3, a driving screw 5 and a precision light tracker 4, and its main function is to automatically track the azimuth of the sun in real time, ensure that the light is vertically irradiated on the surface of the test sample, realize the adjustment of the irradiation spot size, and simulate the real outdoor sunlight conditions. In the present application, the light tracking control unit adopts a frame structure, the Fresnel lens 1 is installed at the top of the frame structure, the focal length adjustment track 3 is arranged along the column direction of the frame structure, and the driving screw 5 and the precision light tracker 4 act on the frame structure to drive the Fresnel lens 1 to automatically track the light in all-weather outdoor conditions.

[0039] The photo-thermal conversion storage unit mainly consists of a sample bin 10 and a heat insulation protective sleeve 11, and can further comprise a sample placement platform 7. The unit is used to place the phase change thermal storage material sample to be tested, and to ensure the temperature stability and leakage prevention effect of the sample during the test. The heat insulation protective sleeve 11 is a protective structure of the sample bin 10 and is fixedly arranged outside the sample bin 10. The sample bin 10 can follow the light tracking action of the aforementioned frame structure, and is installed in the frame structure and can move along the column direction of the frame structure, and is always located below the Fresnel lens 1. Specifically, it can be directly installed on the focal length adjustment track 3 and can move along the focal length adjustment track 3. When the sample placement platform 7 is arranged, the sample placement platform 7 is vertically installed on the focal length adjustment track 3 and can move along the focal length adjustment track 3. At this time, the sample bin 10 can be fixed on the sample placement platform 7 to realize indirect arrangement on the focal length adjustment track 3. By moving the sample bin 10 on the focal length adjustment track 3 along the column direction, the distance between the sample to be tested and the Fresnel lens 1 is adjusted.

[0040] The data acquisition and processing unit mainly comprises a temperature sensor 12, an outdoor temperature acquisition device 8, a light power meter 2, a wind speed and direction instrument 9 and a data processor 6, the temperature sensor 12, the outdoor temperature acquisition device 8, the light power meter 2 and the wind speed and direction instrument 9 acquire and transmit various test data in real time, and the data processor 6 automatically calculates and displays the light-heat conversion rate of the phase change heat storage material, wherein the number of the temperature sensor 12 is multiple, and the temperature sensor 12 is arranged at different height positions of the sample bin 10, and the working temperature of the temperature sensor 12 is-30 DEG C to 1200 DEG C.

[0041] In the embodiment of the present application, the Fresnel lens 1 is located at the top of the device, parallel to the cross section of the sample bin 10, with a length of 1 m and a width of 1 m, and a focal length of 1 m, so as to ensure that sunlight can be accurately projected to the center position of the sample bin 10, and the sunlight can be effectively focused to irradiate the sample surface, the stroke of the focal length adjusting track 3 is 0-1 m, the distance between the sample bin 10 and the Fresnel lens 1 is adjusted within the focal length range, and then the size range of the light spot is controlled to be 5-150 mm, for example, when the distance is adjusted to 0.9 m, the light spot diameter d is 20 mm.

[0042] A specific structure of the light tracking control unit is that a precision light tracker 4 is mounted on the frame structure, a support is connected to the bottom of the frame structure through a horizontal rotating shaft, the support is connected to the frame structure through a driving screw 5 arranged along the column direction of the frame structure, and the horizontal rotating shaft is always perpendicular to the column direction, that is, the frame structure can rotate along the horizontal rotating shaft to track the sun. Obviously, the direction of the horizontal rotating shaft needs to be set according to the sunrise and sunset direction of the use place.

[0043] Further, the precision light tracker 4 and the sample bin 10 are installed at the same horizontal position in the present application, the photoelectric sensing element built in the precision light tracker 4 converts the light intensity into an electric signal to control the start and stop of the motor of the driving screw 5 and the rotating direction of the rotating shaft, so as to control the pitch angle and the direction of the device, so that the plane of the Fresnel lens 1 always faces the sunlight, and ensure that the light always vertically irradiates the sample surface, and the all-weather tracking is realized.

[0044] The sample bin 10 of the present application can be made of high-temperature-resistant stainless steel or similar materials, and the maximum working temperature of the sample is 800 DEG C. A sample lining frame is arranged in the bin, and the size range is 10-100 mm, and the size of the sample lining frame in the embodiment is 20*20*20 mm, which is used to adapt to phase change heat storage materials with different sizes. The external heat insulation protective sleeve 11 can prevent heat loss to the environment and prevent the phase change heat storage material from leaking.

[0045] In the embodiment of the present application, the sample to be tested is a composite phase change heat storage material composed of stearic acid as a phase change heat storage material and expanded graphite as an additive with a mass ratio of 8:2, and the total mass m is 0.2 kg, and the specific heat capacity c is obtained by a specific heat capacity measuring instrument and is 0.4 J / (g·K).

[0046] The working principle of the device is as shown in Figure 5 When the test starts, first, the sample to be tested is placed in the sample bin 10, the focal length adjustment track 3 and the sample placement platform 7 are adjusted to ensure that the distance between the sample and the Fresnel lens 1 is within the focal length range of the Fresnel lens 1, for example, 0.9 m. Then, the precision light tracker 4 is started to automatically track the position of the sun, and the screw rod 5 is driven to adjust the angle of the lens, so that the sunlight is always perpendicular to the sample surface. The light power meter 2 measures and records the solar irradiance P in real time, the temperature sensor 12 collects the internal temperature change ΔT of the sample in real time, the wind speed and direction instrument 9 and the outdoor temperature collection device 8 record the environmental changes, and all data are automatically processed by the data processor 6 according to The photo-thermal conversion rate η in time t is calculated, and the results are output on the display. The test time period is 8:00-17:00, and the test results are as shown in Figure 6 The results show that the photo-thermal conversion rate of the material gradually increases after the test starts, reaches a peak at 12:00-14:00, and then gradually decreases.

[0047] In summary, the all-weather light tracking phase change heat storage material photo-thermal conversion rate automatic test device designed by the present application can effectively realize the comprehensive evaluation of the photo-thermal conversion rate of the phase change heat storage material by simulating the light conditions and environmental changes in the real environment. The device considers the testing needs of samples of different sizes, and the integrated data acquisition and processing system greatly simplifies the test process and reduces the calculation steps in the traditional test method. The device has a simple structure, convenient operation, and certain application potential.

[0048] Although the above describes the embodiments of the present application, those skilled in the art can still make changes and modifications according to the inventive concept of the present application, so the content of the specification is only one embodiment of the present application, and is not limited to the protection scope of the present application. Any equivalent transformation or direct or indirect application in other related technical fields using the content described in the present application is included in the protection scope of the present application, and should not be understood as a limitation of the present application.

Claims

1. An all-weather automatic testing device for light-heat conversion rate of phase change heat storage material light chasing, characterized in that, The application relates to a light tracking device for testing the light-heat conversion rate of phase change heat storage materials, which comprises the following parts: a light tracking control unit for automatically tracking light in all-weather outdoor conditions, a frame structure, and a Fresnel lens (1) arranged on the top of the frame structure; a light-heat conversion storage unit for placing a sample to be tested and keeping the sample warm, wherein the unit comprises a sample bin (10) provided with a heat insulation protective sleeve (11), the sample bin (10) is arranged in the frame structure and can move along the column direction of the frame structure and is always located below the Fresnel lens (1); and a data acquisition and processing unit for automatically collecting, transmitting and processing data in real time, wherein the unit comprises a temperature sensor (12), an outdoor temperature acquisition device (8), a light power meter (2), a wind speed and direction meter (9) and a data processor (6), the temperature sensor (12) is arranged at different height positions of the sample bin (10) and the number of the temperature sensor (12) is multiple. The column direction of the frame structure is provided with a focal length adjusting track (3), and the sample bin (10) is arranged on the focal length adjusting track (3) directly or indirectly so as to move along the column direction of the focal length adjusting track (3) and adjust the distance from the sample bin (10) to the Fresnel lens (1). The Fresnel lens (1) is parallel to the cross section of the sample bin (10), so that sunlight can be accurately projected to the center position of the sample bin (10); the distance between the sample bin (10) and the Fresnel lens (1) is adjusted through the focal length adjusting track (3), so that the size of a light spot can be controlled, and the size range of the light spot is 5-150 mm. A precision light tracker (4) is arranged on the frame structure, the bottom of the frame structure is connected with a support column through a horizontal rotating shaft, the support column is connected with the frame structure through a driving screw (5) arranged along the column direction, and the horizontal rotating shaft is perpendicular to the column direction.

2. The automatic device for testing the photo-thermal conversion rate of phase change heat storage materials for all-weather light chasing according to claim 1, characterized in that, The precision light tracker (4) and the sample bin (10) are arranged at the same horizontal position, the photoelectric sensing element arranged in the precision light tracker (4) converts light intensity into an electric signal to control the start and stop of a motor of the driving screw (5) and the rotating direction of a rotating shaft, so as to control the pitch angle and the direction of the device, make the plane of the Fresnel lens (1) always face the sunlight, ensure that light is always vertically irradiated on the sample surface, and realize all-weather tracking.

3. The automatic device for testing the photo-thermal conversion rate of phase change heat storage material for all-weather light chasing according to claim 2, characterized in that, The light-heat conversion storage unit further comprises a sample placing platform (7).

4. The automatic device for testing the photo-thermal conversion rate of phase change heat storage material for all-weather light chasing according to claim 1, characterized in that, The sample placing platform (7) is arranged in the frame structure, the sample bin (10) is arranged on the sample placing platform (7), the sample bin (10) is made of high-temperature-resistant stainless steel, is internally provided with a sample lining frame with a size range of 10-100 mm for adapting to phase change heat storage materials with different sizes, and is externally provided with a heat insulation protective sleeve (11) for preventing heat loss to the environment and phase change heat storage material leakage.

5. The automatic device for testing the photo-thermal conversion rate of phase change heat storage material for all-weather light chasing according to claim 4, characterized in that, The working temperature of the temperature sensor (12) is -30-1200 DEG C.

6. The automatic device for testing the photo-thermal conversion rate of phase change heat storage materials for all-weather light chasing according to claim 1, characterized in that, The data processor (6) collects the data collected by the temperature sensor (12), the outdoor temperature acquisition device (8), the light power meter (2) and the wind speed and direction meter (9), automatically calculates and displays the light-heat conversion rate of the phase change heat storage material in real time. The application further discloses a method for testing the light-heat conversion rate of phase change heat storage materials, which comprises the following steps:

7. The automatic device for testing the photo-thermal conversion rate of phase change heat storage material for all-weather light chasing according to claim 1, characterized in that, ​ 8. The automatic device for testing the photo-thermal conversion rate of phase change heat storage materials for all-weather light chasing according to claim 1, characterized in that, ​ 9. The automatic testing method of the automatic testing device for photo-thermal conversion rate of phase change heat storage material based on all-weather light chasing according to claim 1, characterized in that, ​ Put the sample to be tested into the sample chamber (10), adjust the distance between the sample to be tested in the sample chamber (10) and the Fresnel lens (1), so that the sample is within the focal length range of the Fresnel lens (1); Start the precision light tracker (4) to automatically track the position of the sun, drive the screw rod (5) to adjust the angle of the lens, so that the sunlight is always vertically irradiated to the surface of the sample to be tested; The light power meter (2) measures and records the solar irradiance P in real time, the temperature sensor (12) collects the internal temperature change of the sample ΔT in real time, the wind speed and direction meter (9) and the outdoor temperature collection device (8) record the environmental changes, and all the data are sent to the data processor (6) to calculate the photo-thermal conversion rate η in time t according to the formula The photo-thermal conversion rate η in time t is calculated.

10. The automatic testing method of claim 9, wherein, The internal temperature change ΔT is collected by the following method: The temperature sensors (12) at different height positions collect the internal temperature of the sample chamber (10) in real time, and the data processor (6) obtains the average value to obtain the internal temperature change ΔT.

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