A photothermal efficiency measurement device and method

Abstract

A photothermal efficiency measurement device and method, the device comprises a solar simulator, a half mirror, a current detector, a comparison integrating sphere, a black body, a temperature difference cooling sheet, a base and a test integrating sphere; a sample to be tested is arranged on the base, the test integrating sphere is arranged on the upper surface of the sample to be tested, the comparison integrating sphere is arranged on the black body and the test hole of the comparison integrating sphere is in contact with the upper surface of the black body, the method comprises first placing the sample to be tested on the base so that the upper surface of the sample to be tested is flush with the upper surface of the black body; then installing the temperature difference cooling sheet between the detection holes of the test integrating sphere and the comparison integrating sphere; an energy detector records the test results; the temperature of the black body is adjusted, and the indication of the current detector is observed. The present invention uses the method of equivalent black body to centrally integrate the influence of factors such as the self-reflection, self-radiation and incident light of the upper coating of the sample to be tested on the test results, which greatly improves the accuracy of the final test results.

Description

Technical Field

[0001] The invention relates to a solar energy device, and in particular to a photothermal efficiency measurement device and method. Background Art

[0002] As a renewable energy source, solar energy has been continuously used by humans in the form of thermal radiation. At a time when fossil fuels are decreasing and attention is paid to environmental protection, solar energy has become increasingly important in the energy used by humans. The basic ways of using solar energy can be divided into four categories: light-heat utilization, light-electricity utilization, light-chemical utilization, and light-biological utilization. Among the four types of solar energy utilization, light-heat conversion technology is the most mature, with the most products and relatively low cost. It collects solar radiation energy and converts it into thermal energy through interaction with matter for utilization, such as solar water heaters, water heaters, solar cookers, etc. Take solar water heaters as an example. The sunlight shines through the first layer of glass of the heat-absorbing tube to the black heat-absorbing layer of the second layer of glass, absorbing the heat of the solar energy. Most of the absorbed heat is transferred to the water in the glass jar, heating the water in the glass tube. The heated water becomes lighter and goes up along the heating surface of the glass tube into the heat-insulating water storage barrel. The relatively low temperature water in the barrel goes into the glass tube along the backlight side of the glass tube for replenishment. This continuous cycle keeps the water in the heat-insulating water storage barrel heated, thus achieving the purpose of hot water. However, the black heat-absorbing layer coated on the outer wall of the second tube cannot introduce all the received solar heat into the tube. Some of the energy will inevitably be lost due to the self-radiation of the black heat-absorbing layer. Therefore, how to measure the lost heat becomes the key to calculating the photothermal efficiency.

[0003] The existing test methods are to first measure the emissivity of the surface coating, then measure its temperature after the coating is exposed to sunlight, and finally use the formula (where ε 涂层 The emissivity of the coating is calculated to obtain the energy lost by thermal radiation of the coating, and then the photothermal efficiency is calculated. However, this method must first know the emissivity of the material used as the coating, and then use a thermocouple to measure the temperature of the sample during the test, and finally use the formula to calculate the heat lost by the material due to its own radiation. This method is not only cumbersome but also inconvenient for later operation. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a photothermal efficiency measurement device and method, which can solve the problems of cumbersomeness and inconvenience of the prior test method.

[0005] A photothermal efficiency measuring device comprises a solar simulator, a half-mirror, a current detector, a comparison integrating sphere, a black body, a temperature difference cooling sheet, a base and a test integrating sphere; a sample to be tested is arranged on the base, the test integrating sphere is arranged on the upper surface of the sample to be tested, and a test hole of the test integrating sphere is fitted with the upper surface of the sample to be tested, the comparison integrating sphere is arranged on the black body, and the test hole of the comparison integrating sphere is fitted with the upper surface of the black body, the temperature difference cooling sheet is arranged between the test integrating sphere and the comparison integrating sphere and is spaced apart from the two, a half-mirror and a solar simulator are arranged above the test integrating sphere from bottom to top, the temperature difference cooling sheet is connected to the current detector, and the light source of the solar simulator, the focus of the half-mirror, the light inlet of the test integrating sphere and the center of the sample to be tested are in a straight line.

[0006] A method for measuring photothermal efficiency comprises the following steps:

[0007] S1. First place the sample to be tested on the base so that the upper surface of the sample to be tested is flush with the upper surface of the black body;

[0008] S2. Adjust the height of the test integrating sphere so that the test hole of the test integrating sphere fits the upper surface of the sample to be tested, and then adjust the height of the comparison integrating sphere so that the test hole of the comparison integrating sphere fits the upper surface of the black body, and then install the temperature difference cooling sheet between the detection holes of the test integrating sphere and the comparison integrating sphere;

[0009] S3, set the light source output power of the solar simulator, wait for the light source output to stabilize, and the energy detector records the test result as Q. Among them, Q 灯 is the output energy of the solar simulator; Q 入射 The energy of the light source incident on the upper coating of the sample to be tested;

[0010] S4. Adjust the temperature of the black body and observe the reading of the current detector. When the reading is zero and remains for a period of time, record the temperature T of the black body at this time; the radiation energy Q of the black body 黑体辐射 =σT 4 , σ is the Boltzmann constant;

[0011] S5. Calculate the photothermal efficiency of the upper coating of the sample to be tested;

[0012]

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The measuring device of the present invention has a simple structure and stable and reliable measurement. Compared with the traditional testing method, the measuring method of the present invention does not need to perform emissivity test on the upper coating, which saves time and does not have very high requirements on the testing equipment. Moreover, since it is not necessary to know the temperature of the upper coating of the sample to be tested, there is no need to bury a thermocouple in the upper coating of the sample to be tested, thereby maintaining the integrity of the upper coating of the sample to be tested. Moreover, the device uses the equivalent black body method to centrally integrate the influence of factors such as the self-reflection, self-radiation and incident light of the upper coating of the sample to be tested on the test results, thereby greatly improving the accuracy of the final test results.

[0015] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments: BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of the light-heat efficiency measuring device of the present invention. DETAILED DESCRIPTION

[0017] like Figure 1 As shown, a photothermal efficiency measuring device of the present embodiment comprises a solar simulator (1), a semi-transparent mirror (2), a current detector 3, a comparison integrating sphere 4, a black body 5, a temperature difference cooling sheet 6, a base 7 and a test integrating sphere 9;

[0018] A sample to be tested 8 is arranged on the base, a test integrating sphere 9 is arranged on the upper surface of the sample to be tested 8, and a test hole of the test integrating sphere 9 is fitted with the upper surface of the sample to be tested 8, a comparison integrating sphere 4 is arranged on a black body 5, and a test hole of the comparison integrating sphere 4 is fitted with the upper surface of the black body 5, a temperature difference cooling sheet 6 is arranged between the test integrating sphere 9 and the comparison integrating sphere 4 and is spaced apart from the two, a half mirror 2 and a solar simulator 1 are arranged from bottom to top above the test integrating sphere 9, the temperature difference cooling sheet 6 is connected to the current detector 3, and the light source of the solar simulator 1, the focus of the half mirror 2, the light inlet of the test integrating sphere 9 and the center of the sample to be tested 8 are in a straight line. The half mirror is a semi-reflective half mirror.

[0019] The light beam of the solar simulator 1 passes concentrically through the focus of the semi-transparent mirror 2, the light inlet of the test integrating sphere 9 and the center of the sample to be tested 8. Such an arrangement is conducive to the full transmission and lossless utilization of energy, ensuring the full and accurate measurement of the photothermal efficiency. The test integrating sphere 9 and the comparison integrating sphere 4 respectively concentrate the radiation energy of the sample coating and the black body to the temperature difference cooling plate 6 after multiple reflections, and the energy loss of the gold-plated integrating sphere reflection can be basically ignored. The sample to be tested 8 can be coated with solar energy absorption coatings such as aluminum anodized coating, black chrome coating, black nickel coating or CuO conversion coating.

[0020] Usually, the temperature difference cooling sheet 6 is a semiconductor cooling sheet. It has no moving parts and good reliability. In actual use, it is also equipped with an energy detector 10, and the reflected energy of the semi-mirror 2 is absorbed by the energy detector 10.

[0021] Based on the light-thermal efficiency measurement device of the above embodiment, a light-thermal efficiency measurement method is also proposed, comprising:

[0022] S1. First, place the sample 8 to be tested on the base 7 so that the upper surface of the sample 8 to be tested is flush with the upper surface of the black body 5;

[0023] S2, adjust the height of the test integrating sphere 9 so that the test hole of the test integrating sphere 9 fits with the upper surface of the sample 6 to be tested, and the light source of the solar simulator 1, the focus of the semi-transparent mirror 2, the light inlet of the test integrating sphere 9 and the center of the sample 8 to be tested are in a straight line, and then adjust the height of the comparison integrating sphere 4 so that the test hole of the comparison integrating sphere 4 fits with the upper surface of the black body 5, and then install the temperature difference cooling sheet 6 between the detection holes of the test integrating sphere 9 and the comparison integrating sphere 4;

[0024] The function of the temperature difference cooling sheet 6 is to detect the thermal radiation energy inside the two integrating spheres. The current detected by the differential current detector 3 is not 0, which is convenient for adjusting the temperature of the black body, and finally makes the output current of the temperature difference cooling sheet 6 0;

[0025] S3, set the light source output power of the solar simulator 1 to P, wait for the light source output to stabilize, and then the energy detector 10 records the test result as Q. Due to the semi-transparent mirror, the test result of the energy detector 10 should be half of the light source output energy and equal to the energy incident on the upper coating of the sample to be tested 8, that is, Among them, Q 灯 is the output energy of the solar simulator 1, Q 入射 The energy of the light source incident on the coating on the sample to be tested;

[0026] After the light from the solar simulator 1 enters the test integrating sphere 9, except for the energy transmitted from the upper coating of the sample 8 to the lower coating, all the remaining energy is radiated to the temperature difference cooling plate 6. According to the law of conservation of energy, we get:

[0027] Q 入射 =Q 传导 +Q 损失

[0028] S4. Adjust the temperature of the black body 5 and observe the reading of the current detector 3. When the reading is zero and remains for a period of time, record the temperature T of the black body 5 at this time; the radiation energy Q of the black body 黑体辐射 =σT 4 , σ is the Boltzmann constant;

[0029] When the reading of the current detector 3 is zero, the radiation energy received by the two sides of the temperature difference cooling plate 6 is equal, that is, the radiation energy lost by the incident light is equal to the black body radiation energy at this time, that is:

[0030] Q 损失 =Q 黑体辐射

[0031] It can be concluded that the energy transmitted through the upper coating of the sample 8 to be tested is:

[0032] Q 传导 =Q 入射 -Q 损失 =Q 入射 -Q 黑体辐射

[0033] S5, calculating the photothermal efficiency of the upper coating of the sample 8 to be tested;

[0034]

[0035] In the above step S1, the base is made of three pieces of heat-insulating material. To reduce the radiation loss, the contact area between the base 7 and the sample to be tested 8 should be as small as possible.

[0036] In step S2, the temperature difference cooling sheet 6 is installed between the test integrating sphere 9 and the comparison integrating sphere 4. In order to prevent the test integrating sphere 9 and the temperature difference cooling sheet 6 from heat conduction and causing inaccurate measurement results, the temperature difference cooling sheet 6 needs to be installed at a certain distance from the outer walls of the two integrating spheres. If it touches, it will affect the measurement results. If it is too far away, it will cause energy overflow, and part of the energy of the cooling sheet cannot be detected. The experiment shows that the two sides of the temperature difference cooling sheet 6 are kept at a distance of 1-2mm from the outer walls of the test integrating sphere 9 and the comparison integrating sphere 4.

[0037] The present invention has been disclosed as above with preferred implementation cases, but it is not used to limit the present invention. Any technician familiar with the profession can make slight changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention, which still fall within the scope of the technical solution of the present invention.

Claims

1. A method for measuring photothermal efficiency, characterized in that: Include: S1. First, place the sample to be tested (8) on the base (7) so that the upper surface of the sample to be tested (8) is flush with the upper surface of the black body (5); S2, adjusting the height of the test integrating sphere (9) so that the test hole of the test integrating sphere (9) fits the upper surface of the sample to be tested (8), and then adjusting the height of the comparison integrating sphere (4) so ​​that the test hole of the comparison integrating sphere (4) fits the upper surface of the black body (5), and then installing the temperature difference cooling sheet (6) between the detection holes of the test integrating sphere (9) and the comparison integrating sphere (4); S3, setting the light source output power of the solar simulator (1), waiting for the light source output to stabilize, and the energy detector (10) records the test result as Q, Among them, Q 灯 is the output energy of the solar simulator; Q 入射 It is the energy of the light source incident on the upper coating of the sample to be tested; S4. Adjust the temperature of the black body (5) and observe the reading of the current detector (3). When the reading reaches zero and remains zero for a period of time, record the temperature T of the black body (5) at this time; the radiation energy Q of the black body 黑体辐射 =σT 4 , σ is the Boltzmann constant; S5. Calculate the photothermal efficiency of the upper coating of the sample to be tested (8):

2. A method for measuring photothermal efficiency according to claim 1, characterized in that: In step S1, the base (7) is made of three pieces of heat-insulating material.

3. A method for measuring photothermal efficiency according to claim 2, characterized in that: In step S2, the light source of the solar simulator (1), the focus of the semi-transparent mirror (2), the light inlet of the test integrating sphere (9) and the center of the sample to be tested (8) are on a straight line.

4. The method for measuring photothermal efficiency according to claim 1, characterized in that: The temperature difference cooling plate (6) is installed between the test integrating sphere (9) and the comparison integrating sphere (4), and the two sides of the temperature difference cooling plate (6) are respectively kept at a distance of 1-2 mm from the outer walls of the test integrating sphere (9) and the comparison integrating sphere (4).

5. The method for measuring photothermal efficiency according to claim 1, characterized in that: In step S3, after the light from the solar simulator (1) enters the test integrating sphere (9), except for the energy transmitted from the upper coating of the sample to be tested (8) to the lower coating, all the remaining energy is radiated to the temperature difference cooling plate (6). According to the law of conservation of energy, the following is obtained: Q 入射 =Q 传导 +Q 损失 In step S4, when the reading of the current detector (3) is zero, the radiation energy received by the two sides of the temperature difference cooling plate (6) is equal, that is, the radiation energy lost by the incident light is equal to the black body radiation energy at this time, that is: Q 损失 =Q 黑体辐射 It can be concluded that the energy conducted through the upper material of the sample to be tested (8) is: Q 传导 =Q 入射 -Q 损失 =Q 入射 -Q 黑体辐射 The photothermal efficiency of the upper coating of the sample to be tested (8) can be obtained as:

6. A photothermal efficiency measurement device for implementing the photothermal efficiency measurement method of claim 1, characterized in that: It comprises a solar simulator (1), a half mirror (2), a current detector (3), a comparison integrating sphere (4), a black body (5), a temperature difference cooling sheet (6), a base (7) and a test integrating sphere (9); A sample to be tested (8) is arranged on a base (7); a test integrating sphere (9) is arranged on the upper surface of the sample to be tested (8), and a test hole of the test integrating sphere (9) is fitted with the upper surface of the sample to be tested (8); a comparison integrating sphere (4) is arranged on a black body (5), and a test hole of the comparison integrating sphere (4) is fitted with the upper surface of the black body (5); a temperature difference cooling sheet (6) is arranged between the test integrating sphere (9) and the comparison integrating sphere (4) and is spaced apart from the two; a semi-transparent mirror (2) and a solar simulator (1) are arranged above the test integrating sphere (9) from bottom to top; the temperature difference cooling sheet (6) is connected to a current detector (3); and a light source of the solar simulator (1), a focus of the semi-transparent mirror (2), a light inlet of the test integrating sphere (9) and the center of the sample to be tested (8) are on a straight line.

7. The photothermal efficiency measuring device according to claim 6, characterized in that: The temperature difference cooling plate (6) is a semiconductor cooling plate.

8. The photothermal efficiency measuring device according to claim 6, characterized in that: It also comprises an energy detector (10), and the reflected energy of the semi-transparent mirror (2) is absorbed by the energy detector (10).

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