The best sunlight angle of solar panels---Benwei solar street lights
The inclination angle of solar cell modules (referring to the angle between the plane of the solar cell panel and the ground plane) has been discussed in many technical circles. The angle of inclination is determined according to the geographic location (latitude, etc.); the front of the solar panel is facing the sun (or slightly west from the south), and the inclination angle is the same as the local latitude. If conditions permit.
Solar energy is a kind of clean energy, and its application is growing rapidly all over the world. Using solar power to generate electricity is a way to use solar energy, but the cost of building a solar power system is still relatively high. Judging from the current cost of solar power generation in China, the cost of solar cell components is about 60-70. %. Therefore, in order to use solar energy more fully and effectively, how to select the azimuth and inclination angle of the solar cell array is a very important issue.
1. Azimuth
The azimuth angle of the solar cell array is the angle between the vertical plane of the array and the positive south direction (the eastward deviation is set as a negative angle, and the westward deviation is set as a positive angle). Under normal circumstances, when the square array faces true south (that is, the angle between the vertical plane of the square array and true south is 0°), the solar cell generates the largest amount of electricity. When it deviates from the true south (Northern Hemisphere) by 30°, the power generation of the square array will be reduced by about 10% to 15%; when it deviates from the true south (Northern Hemisphere) by 60°, the power generation of the square will be reduced by about 20% to 30%. . However, in a sunny summer, the maximum time of solar radiation energy is after noon, so when the orientation of the square array is slightly westward, the maximum power generation can be obtained in the afternoon. In different seasons, the orientation of the solar cell phalanx is slightly east or west when the power generation capacity is the largest. The location of the square array is restricted by many conditions, such as the azimuth angle of the land when it is installed on the ground, the azimuth angle of the roof when it is installed on the roof, or the azimuth angle when it is used to avoid the shadow of the sun, as well as layout planning, power generation efficiency, Many factors such as design planning and construction purpose are related. If you want to adjust the azimuth angle so that the peak load moment and the peak power generation moment of the day coincide, please refer to the following formula. As for grid-connected power generation, it is hoped that the azimuth angle should be selected by considering the above aspects. Azimuth = (peak time of day load (24-hour clock)-12) × 15 + (longitude-116) When the solar cell array in Beijing is at different azimuths on October 9th, the relationship curve between solar radiation and the passage of time. In different seasons, the peak insolation time of each azimuth is different.
2. Tilt angle
The angle of inclination is the angle between the plane of the solar cell array and the horizontal ground, and it is hoped that this angle is the best angle of inclination when the power generation of the array is the largest in a year. The best tilt angle in a year is related to the local geographic latitude. When the latitude is higher, the corresponding tilt angle is also large. However, as with the azimuth angle, the design should also consider the restrictive conditions of the inclination angle of the roof and the inclination angle of snow falling (the slope is greater than 50%-60%). For the slope angle of snow fall, the total annual power generation may increase even if the amount of power generation is small during the snow accumulation period. Therefore, especially in grid-connected power generation systems, snow fall is not necessarily prioritized. , And other factors must be further considered. For true south (azimuth angle is 0°), when the tilt angle is gradually transitioning from horizontal (tilt angle is 0°) to the best tilt angle, its insolation will continue to increase until the maximum, and then increase the tilt angle. The amount of solar radiation continues to decrease. Especially after the inclination angle is greater than 50°-60°, the solar radiation will drop sharply, until the final vertical placement, the power generation will drop to a minimum. There are practical examples for the square matrix from vertical placement to 10°～20° oblique placement. For the case where the azimuth angle is not 0°, the value of the slope insolation is generally low, and the value of the maximum insolation is near the inclination angle close to the horizontal plane. The above is the relationship between the azimuth angle, the inclination angle and the power generation. For the specific design of the azimuth and inclination angle of a square array, it should be further considered in combination with the actual situation.
3. The influence of shadows on power generation
Under normal circumstances, when we calculate the power generation, we get it under the premise that there is no shadow at all on the square front. Therefore, if the solar cell cannot be directly illuminated by sunlight, only the scattered light is used to generate electricity. At this time, the amount of electricity generated will be reduced by about 10% to 20% compared with that without shadows. In view of this situation, we have to correct the theoretical calculation value. Usually, when there are buildings and mountain peaks around the square array, there will be shadows around the buildings and mountains after the sun comes out. Therefore, you should try to avoid shadows when choosing a place to lay the square array. If it is impossible to avoid it, it should also be solved from the wiring method of the solar cell to minimize the influence of the shadow on the power generation. In addition, if the square matrix is placed front and back, the distance between the back square and the front square is close, the shadow of the front square will affect the power generation of the back square. There is a bamboo pole with a height of L1, the shadow length in the north-south direction is L2, and the sun height (elevation angle) is A. When the azimuth angle is B, assuming the shadow magnification is R, then: R = L2/L1 = ctgA×cosB This formula should be calculated on the day of the winter solstice, because that day has the longest shadow. For example, the height of the upper edge of the square matrix is h1, and the height of the lower edge is h2, then: the distance between the square matrix a=(h1-h2)×R. When the latitude is higher, the distance between the square matrices increases, and the area of the installation site will increase accordingly. For the square matrix with anti-snow measures, its inclination angle is large, so the height of the square matrix is increased. In order to avoid the influence of shadow, the distance between the square matrix will be increased accordingly. Usually when arranging square arrays, the structural dimensions of each square should be selected separately, and its height should be adjusted to an appropriate value, so as to use its height difference to adjust the distance between the squares to a minimum. The specific solar cell phalanx design, while reasonably determining the azimuth and inclination angle, should also be comprehensively considered in order to achieve the best state of the phalanx.
