Roof fixed photovoltaic panel optimal structure calculation method considering temperature correction

Abstract

The invention discloses a method for calculating the optimal structure of a roof fixed photovoltaic panel considering temperature correction, which aims at the calculation of the solar radiation intensity of the surface of the photovoltaic panel, does not need field solar radiation data, and is determined by the longitude and latitude, date and time of a field through a solar incidence elevation angle, a solar incidence azimuth angle and a solar radiation constant. The influence of solar radiation, environment temperature and environment wind speed on the photovoltaic power generation efficiency through the surface temperature of the photovoltaic panel is considered, and the influence is added into calculation of the solar radiation intensity of the photovoltaic panel to serve as correction. And the solar radiation intensity with temperature correction on the surface under different structural parameters of the photovoltaic panel is calculated through the latitude and longitude of the site. And by comparing results under different photovoltaic panel structure parameters, an optimal structure design with the maximum annual solar radiation intensity total amount containing temperature correction as a target can be obtained. The method can be applied to a scene without historical solar radiation data, and temperature correction is introduced, so that the conclusion is more practical.

Description

Technical Field

[0001] The invention relates to a calculation method for an optimal structure of a roof-fixed photovoltaic panel taking temperature correction into consideration, and belongs to the technical field of photovoltaic power generation. Background Art

[0002] As climate change becomes increasingly serious, humans need more energy to meet the needs of living space and daily life, which leads to energy shortages. As an indispensable part of human daily life, buildings not only need to meet basic human needs, but also bear the human yearning for a better life. Therefore, the construction industry has become one of the important sources of global carbon emissions. Since renewable energy is different from non-renewable energy, it has less environmental pollution and low carbon emission intensity, so it has become an important means to reduce carbon emissions from buildings.

[0003] Among them, photovoltaic resources are an important part of renewable resources. They use the photovoltaic effect of semiconductor interfaces to directly convert light energy into electrical energy. Photovoltaic panels can be fully integrated with buildings and installed on large roofs to generate electricity to meet part of the daily electricity needs of buildings. This technology is closely integrated with buildings, and the wide application area of ​​building facades and roofs makes it have considerable application potential. At the same time, its structure is simple. Unlike wind power generation and hydropower generation, it does not require large-scale power generation and power supply equipment.

[0004] Rooftop photovoltaics are divided into tracking and fixed types. Tracking photovoltaic systems are more complex than fixed ones and have high maintenance costs, so fixed photovoltaic systems have become the first choice for rooftops of vast buildings. The power generation of photovoltaic panels is proportional to the surface radiation intensity and power generation efficiency of photovoltaic panels. At present, there are related technologies for calculating the optimal structural parameters of fixed photovoltaic panels with the maximum power generation as the goal. For example, the invention patent with publication number CN115130245A discloses a method for calculating the optimal inclination angle of fixed photovoltaic panels. This patent only considers the total amount of solar radiation acceptable to photovoltaic panels with different structural parameters, and does not consider the influence of solar radiation and ambient temperature on photovoltaic power generation efficiency and photovoltaic power generation through the surface temperature of photovoltaic panels. In addition, this patent requires obtaining solar radiation intensity data of the site in the early stage. This data is difficult to obtain for areas where meteorological data collection is not comprehensive and photovoltaic resources have never been developed before. Therefore, the optimal structural parameters of photovoltaic panels calculated by this patent are somewhat different from the actual situation, and there is a distance from actual promotion and application.

[0005] In summary, there are currently problems with huge carbon emissions from buildings and inaccurate traditional assessment methods. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a calculation method for the optimal structure of roof-mounted photovoltaic panels taking temperature correction into account.

[0007] The present invention adopts the following technical solutions to solve the above technical problems:

[0008] In one aspect, the present invention provides a method for calculating the optimal structure of a roof-mounted photovoltaic panel taking temperature correction into account, the method comprising:

[0009] Step 1, calculating the solar incidence altitude angle and solar incidence azimuth angle according to the longitude and latitude, solar hour angle, and declination angle of the photovoltaic panel;

[0010] Step 2, establishing a relationship between the photovoltaic panel structural parameters and the solar radiation intensity on the photovoltaic panel surface;

[0011] Step 3, introducing the surface temperature of the photovoltaic panel to perform temperature correction on the solar radiation intensity on the surface of the photovoltaic panel;

[0012] Step 4, count the total solar radiation on the surface of the photovoltaic panel including temperature correction under different photovoltaic panel structural parameters throughout the year, find out the photovoltaic panel structural parameters when the total solar radiation on the surface of the photovoltaic panel including temperature correction throughout the year is the largest (this can be achieved by fitting curves and other methods), which is the calculation result of the optimal structure of the photovoltaic panel.

[0013] Furthermore, the expression of the solar hour angle h is:

[0014]

[0015] Where T m is the average solar time in the time zone where the photovoltaic panel is located, L is the longitude of the photovoltaic panel, and L m is the longitude of the central meridian of the time zone where the photovoltaic panel is located, e is the time difference; "±", for the Eastern Hemisphere, take "+", and for the Western Hemisphere, take "-".

[0016] Furthermore, the expression of the declination angle β is:

[0017]

[0018] Where n is the number of the day in the year for which the calculation day is to be calculated.

[0019] Furthermore, the expression of the solar incidence altitude angle β is:

[0020]

[0021] in is the latitude of the photovoltaic panel; h is the hour angle; δ is the declination angle.

[0022] Furthermore, the expression of the solar incident azimuth angle A is:

[0023]

[0024] Where β is the solar incidence altitude angle; h is the hour angle; δ is the declination angle.

[0025] Furthermore, the relationship between the photovoltaic panel structural parameters and the solar radiation intensity on the photovoltaic panel surface is:

[0026] I=I N ×sin(β+θ)×cos(A+α)

[0027] Among them I N is the normal solar radiation intensity at the earth's surface; β is the solar incidence altitude angle; θ is the photovoltaic panel height inclination angle; A is the solar incidence azimuth angle; α is the photovoltaic panel azimuth inclination angle.

[0028] Furthermore, the normal solar radiation intensity I at the earth's surface N The expression is:

[0029] I N =I0×P m

[0030] Where I0 is the solar constant; P is the atmospheric transparency; m=1 / sinβ is the mass of the atmosphere, and β is the solar altitude angle.

[0031] Furthermore, the expression of the solar radiation intensity I′ on the photovoltaic panel surface including temperature correction is:

[0032] I′=I×[1-η×(TT rate )]

[0033] Where I is the solar radiation intensity on the surface of the photovoltaic panel without temperature correction, η is the temperature coefficient, T is the surface temperature of the photovoltaic panel, and T rate It is the temperature of photovoltaic panels under standard test conditions.

[0034] Furthermore, if T is less than T rate , then I′=I.

[0035] On the other hand, the present invention further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned calculation method when executing the computer program.

[0036] On the other hand, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above-mentioned calculation method when executed by a processor.

[0037] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0038] (1) The present invention calculates the solar radiation intensity on the surface of the photovoltaic panel without requiring site solar radiation data. It is determined by the site longitude and latitude, date, and time through the solar incidence altitude angle, solar incidence azimuth angle, and solar radiation constant.

[0039] (2) The present invention takes into account the influence of solar radiation, ambient temperature and ambient wind speed on the photovoltaic power generation efficiency through the surface temperature of the photovoltaic panel, and adds these influences into the calculation of the solar radiation intensity of the photovoltaic panel as a correction.

[0040] (3) The present invention calculates the temperature-corrected solar radiation intensity of the surface of the photovoltaic panel under different structural parameters through the longitude and latitude of the site. By comparing the results under different photovoltaic panel structural parameters, the optimal structural design with the goal of maximizing the annual total amount of solar radiation intensity including temperature correction can be obtained.

[0041] (4) The present invention can be applied to scenarios without historical solar radiation data. At the same time, the introduction of temperature correction can make the conclusion more realistic, and has broad application prospects and value. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a flow chart for calculating the solar radiation intensity on the surface of a photovoltaic panel including temperature correction in the present invention.

[0043] Figure 2 It is a schematic diagram of the solar incidence altitude angle and azimuth angle.

[0044] Figure 3 This is the relationship curve between the surface solar radiation intensity and the height inclination angle with temperature correction for the optimal structural parameters of photovoltaic panels in Nanjing. DETAILED DESCRIPTION

[0045] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0046] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0047] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0048] In order to improve the efficiency of photovoltaic power generation, the present invention proposes a method for calculating the optimal structure of a roof-fixed photovoltaic panel taking temperature correction into account, including a method for calculating the optimal height inclination angle and the optimal azimuth inclination angle of the roof-fixed photovoltaic panel, which includes calculations of the relationship between the solar incidence height angle and the azimuth angle and the longitude and latitude and date, calculations of the relationship between the solar radiation intensity and the height inclination angle and the azimuth inclination angle of the photovoltaic panel, calculations of the relationship between the surface temperature of the photovoltaic panel and the date, calculations of the solar radiation intensity on the surface of the photovoltaic panel with temperature correction, and calculations of the optimal structural parameters of the photovoltaic panel.

[0049] The calculation of the relationship between the solar incidence altitude angle, the azimuth angle and the longitude and latitude includes steps 1 to 4.

[0050] Step 1: Calculate the declination. The angle between the line connecting the center of the Earth and the center of the Sun and the Earth's equatorial plane is defined as declination, denoted by δ, which is expressed as:

[0051]

[0052] In the above formula, n is the number of the day in a year, such as January 12 is 12.

[0053] Step 2: Calculate the hour angle. The angle between the projection of the sun-earth center line on the Earth's equatorial plane at the moment of the sun's incidence and the sun-earth center line on the equatorial plane at 12 o'clock local true solar time is expressed as h, which can be expressed as:

[0054]

[0055] In the above formula, T m is the average solar time in the time zone, h; L is the longitude of the site, L m is the longitude of the central meridian of the time zone, e is the time difference, min; ±, positive for the Eastern Hemisphere and negative for the Western Hemisphere. The hour angle is zero at 12 o'clock when the true solar time is true, and changes by 15° every hour, such as -30° at 10 o'clock and 30° at 14 o'clock.

[0056] Step 3: Calculate the solar incidence altitude angle. The angle between the sun's rays and the horizontal plane is defined as the solar altitude angle, denoted by β, which can be expressed as:

[0057]

[0058] In the above formula, is the latitude of the site; h is the hour angle, indicating the change of time; δ is the declination, indicating the change of date.

[0059] Step 4: Calculate the solar incidence azimuth. The angle between the projection of the line from the sun to the ground and the local meridian (south) is positive if it is east and negative if it is west. It is represented by A and can be expressed as:

[0060]

[0061] In the above formula, β is the solar incidence altitude angle; h is the hour angle, indicating the change of time; δ is the declination, indicating the change of date.

[0062] The calculation of the relationship between the solar radiation intensity on the photovoltaic panel and the height tilt angle and the azimuth tilt angle of the photovoltaic panel includes steps 5 and 6.

[0063] Step 5: Calculate the normal solar radiation intensity at the earth's surface when the solar altitude angle is β, using I N It is expressed as:

[0064] I N =I0×P m

[0065] In the above formula, I0 is the solar constant, W / m 2 , as shown in Table 1 below; P is the atmospheric transparency. The closer P is to 1, the clearer the atmosphere is. It is generally taken as 0.65-0.75. m is the mass of the atmosphere, which reflects the distance that sunlight passes through the atmosphere, which is 1 / sinβ.

[0066] Table 1 Solar constants for each month

[0067] month 1 2 3 4 5 6 7 8 9 10 11 12 Solar constant 1405 1394 1378 1353 1334 1316 1308 1315 1330 1350 1372 1392

[0068] Step 6: Calculate the relationship between the photovoltaic panel structural parameters and the solar radiation intensity on the photovoltaic panel surface, expressed as I, as follows:

[0069] I=I N ×sin(β+θ)×cos(A+α)

[0070] In the above formula, I N is the normal solar radiation intensity at the earth's surface; β is the solar altitude angle; θ is the photovoltaic panel altitude inclination angle; A is the solar azimuth angle; α is the photovoltaic panel azimuth inclination angle, which is the angle at which the projection of the normal line of the photovoltaic panel surface on the horizontal plane deviates from the local meridian (south), which is negative to the west and positive to the east.

[0071] The calculation of the relationship between the photovoltaic panel surface temperature and the date includes step 7.

[0072] Step 7: Calculate the relationship between the surface temperature of the photovoltaic panel and the date. The calculation is based on the calculation method of the surface temperature of the photovoltaic panel in the reference paper "A detailed modelling method for photovoltaic cells", which is represented by T and is expressed as:

[0073] T=0.943×T a+0.028×i-1.528V+4.3

[0074] In the above formula, T a is the average temperature of the site, ℃; I is the solar radiation intensity on the surface of the photovoltaic panel, W / m 2 ; V is the average wind speed at the site, m / s.

[0075] The calculation of solar radiation intensity including temperature correction on the photovoltaic panel surface includes step 8.

[0076] Step 8: Calculate the solar radiation intensity on the photovoltaic panel surface with temperature correction, expressed as I′, which is expressed as:

[0077] I′=I×[1-η×(TT rate )]

[0078] In the above formula, I is the solar radiation intensity on the photovoltaic panel surface, W / m 2 ; η is the temperature coefficient, % / ℃; T is the surface temperature of the photovoltaic panel, ℃; T rate is the temperature of the photovoltaic panel under standard test conditions, °C. If T is less than T rate Then I′=I.

[0079] The calculation of the optimal structural parameters of the photovoltaic panel includes step 9.

[0080] Step 9: The time unit in the above steps is hour, h. Therefore, the solar radiation intensity and surface temperature of the photovoltaic panel surface at each moment are calculated in hours, and then the solar radiation intensity with temperature correction of the photovoltaic panel at each moment is calculated. The time range is from 8:00 to 16:00 every day. The total solar radiation of the photovoltaic panel surface with temperature correction for the whole year can be obtained by accumulating the calculation results hour by hour. The results under different structural parameters can be obtained by changing the structural parameters of the photovoltaic panel through the code. The optimal structural parameters can be obtained by comparing the results of different structural parameters.

[0081] The following takes Nanjing as an example to clearly describe the technical solution of the present invention.

[0082] First, we need to obtain the site information of Nanjing. Nanjing's latitude is 32° and longitude is 119°. The monthly average temperature data and average wind speed data are shown in Table 2 below:

[0083] Table 2 Monthly average temperature (℃) and wind speed data (m / s) in Nanjing in 2023

[0084] month 1 2 3 4 5 6 7 8 9 10 11 12 temperature 10 10 18 22 26 30 32 32 28 24 18 10 Wind speed 2.8 3.1 3.2 3.6 3.1 2.7 2.9 2.5 2.5 2.4 3.1 2.6

[0085] Taking July in Nanjing as an example, in step 7, the relationship between the surface temperature of the photovoltaic panel and the date is calculated. The calculation method of the surface temperature of the photovoltaic panel in the paper "A detailed modelling method for photovoltaic cells" is referred to, and T is used to represent it, which is expressed as:

[0086] T=0.943×T a +0.028×I-1.528V+4.3

[0087] The calculation result is T = 0.943 × 32 + 0.028 × I - 1.528 × 2.9 + 4.3, where I is the solar radiation intensity on the photovoltaic panel surface, W / m 2 , which can be obtained by calculating from steps 1 to 6.

[0088] The calculation results show that the optimal design parameters are the structural parameters for the south direction and the height inclination angle of 44° under the condition of atmospheric transparency of 0.7 in Nanjing. The relationship curve between the surface solar radiation intensity with temperature correction and the height inclination angle of the structural parameters is shown in the figure below: Figure 3 shown.

[0089] Based on the same technical solution, the present invention also designs an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned method for calculating the optimal structure of the roof-fixed photovoltaic panel when executing the computer program.

[0090] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the above-mentioned method for calculating the optimal structure of the roof-mounted photovoltaic panel are implemented.

[0091] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0092] The above description is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technology can understand and think of any changes or substitutions within the technical scope disclosed by the present invention, which should be included in the scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction, characterized in that: The calculation method includes: Step 1, calculating the solar incidence altitude angle and solar incidence azimuth angle according to the longitude and latitude, solar hour angle, and declination angle of the photovoltaic panel; Step 2, establishing a relationship between the photovoltaic panel structural parameters and the solar radiation intensity on the photovoltaic panel surface; Step 3, introducing the surface temperature of the photovoltaic panel to perform temperature correction on the solar radiation intensity on the surface of the photovoltaic panel; Step 4, the total solar radiation on the surface of the photovoltaic panel including temperature correction throughout the year under different photovoltaic panel structural parameters is counted, and the photovoltaic panel structural parameters when the total solar radiation on the surface of the photovoltaic panel including temperature correction throughout the year is the largest are found, which is the calculation result of the optimal structure of the photovoltaic panel.

2. The method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction according to claim 1 is characterized in that: The expression of the solar hour angle h is: Where T m is the average solar time in the time zone where the photovoltaic panel is located, L is the longitude of the photovoltaic panel, and L m is the longitude of the central meridian of the time zone where the photovoltaic panel is located, and e is the time difference; "±", "+" for the Eastern Hemisphere and "-" for the Western Hemisphere.

3. The method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction according to claim 1 is characterized in that: The expression of declination angle β is: Where n is the number of the day in the year for which the calculation day is to be calculated.

4. The method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction according to claim 1, characterized in that: The expression of the solar incidence altitude angle β is: in is the latitude of the photovoltaic panel; h is the hour angle; δ is the declination angle.

5. The method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction according to claim 1, characterized in that: The expression of the solar incident azimuth angle A is: Where β is the solar incidence altitude angle; h is the hour angle; δ is the declination angle.

6. The method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction according to claim 1, characterized in that: The relationship between the photovoltaic panel structural parameters and the solar radiation intensity on the photovoltaic panel surface is: I=I N ×sin(β+θ)×cos(A+α) Among them I N is the normal solar radiation intensity at the earth's surface; β is the solar incidence altitude angle; θ is the photovoltaic panel height inclination angle; A is the solar incidence azimuth angle; α is the photovoltaic panel azimuth inclination angle.

7. The method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction according to claim 6, characterized in that: Normal solar radiation intensity at the earth's surface I N The expression is: I N =I0×P m Where I0 is the solar constant; P is the atmospheric transparency; m=1 / sinβ is the mass of the atmosphere, and β is the solar altitude angle.

8. The method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction according to claim 1, characterized in that: The expression of solar radiation intensity I′ on the photovoltaic panel surface including temperature correction is: I′=I×[1-η×(T-T rate )] Where I is the solar radiation intensity on the photovoltaic panel surface without temperature correction, η is the temperature coefficient, T is the photovoltaic panel surface temperature, T rate It is the temperature of photovoltaic panels under standard test conditions.

9. The method for calculating the optimal structure of roof-mounted photovoltaic panels considering temperature correction according to claim 8, characterized in that: If T is less than T rate , then I′=I.

10. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the computing method described in any one of claims 1 to 9 are implemented.

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