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Since solar energy is a clean energy source, its application is growing rapidly around the world. Solar power generation is one way to use solar energy, but the cost of building a solar power system is still high. From the perspective of the current cost of solar power generation, the cost of solar cell modules is about 60-70%.
Therefore, in order to make more effective use of solar energy, how to choose the solar panel angle is a very important issue. The selection of azimuth and tilt angles at solar panel angle is one of the most important factors in the design of a solar PV system.
Azimuth determines the direction of incidence of sunlight and determines the lighting conditions of hillsides or buildings in different orientations in all directions. The tilt angle is the angle between the ground plane (horizontal plane) and the solar module. When the tilt angle is 0°, the solar battery is horizontal, and when the tilt angle is 90°, the solar module is vertical.
1. What is solar panel angle-azimuth
The solar panel angle of azimuth is the angle between the vertical plane of the square array and the direction due south (the eastward deviation is set to a negative angle, and the westward deviation is set to a positive angle).
In general, when the square matrix is facing due south (i.e., the angle between the vertical plane of the square and the due south is 0°), the photovoltaic power generation system is the largest.
When it deviates from due south (northern hemisphere) by 30°, the power generation of the phalanx will be reduced by about 10%~15%. When it deviates from the due south (northern hemisphere) by 60°, the power generation of the phalanx will be reduced by about 20%~30%.
However, on a clear summer day, the moment when solar radiates energy is at its most intense is around noon. Therefore, when the solar panel angle is slightly to the west, maximum power can be generated in the afternoon. Depending on the season, solar panels are angled slightly east or west to get the most electricity.
The location of the square array is conditioned by many conditions, such as the azimuth of the land when it is installed on the ground, the azimuth of the roof when it is installed on the roof, or the azimuth of the roof to avoid the shadow of the sun, as well as many factors such as layout planning, power generation efficiency, design planning, and construction purpose.
If you want to adjust the solar panel angle of azimuth so that the load peak time coincides with the peak time of the day when the power generation is at its peak, refer to the formula below. In the case of grid-connected power generation, it is hoped that the azimuth angle will be selected taking into account the above aspects.
Azimuth = (day load peak (24-hour format) - 12) × 15 + (longitude minus 116)
2. What is solar panel angle-tilt angle
The tilt angle is the angle between the plane of the solar panel square and the horizontal ground, and it is hoped that this solar panel angle is the best angle of tilt when the power generation of the square array is the largest in a year.
The optimum solar panel angle of tilt of the year is related to the local geographic latitude, and when the latitude is higher, the corresponding tilt angle is also larger. However, as with azimuth, the design should also take into account the constraints of the roof and the slope of the snow (slope greater than 50%–60%).
In the case of slope angles with snow slipping, there may be an increase in total annual power generation even if the power generation is low during the snow accumulation period. Therefore, especially in systems that are connected to the grid for power generation, the slippage of snow cover is not necessarily a priority. There are also other factors to consider.
For due south (0° azimuth angles), the insolation amount increases to the maximum when the solar panel angle of tilt gradually transitions from horizontal (0° azimuth to 0° degrees), and then decreases as the solar panel angle of tilt increases.
Especially after the tilt angle is greater than 50°~60°, the amount of sunlight drops sharply, and until the final vertical placement, the power generation drops to a minimum. There are practical examples of phalanxes ranging from vertical placement to inclined placement of 10°~20°.
For azimuth angles other than 0°, the values of the insolation in the inclined plane are generally low, and the maximum insolation is near the optimal solar panel angle of tilt close to the horizontal plane.
The above is the relationship between azimuth angle, tilt angle and power generation, and the azimuth angle and tilt angle of a certain square array should be further considered comprehensively and further combined with the actual situation.
3. What is the standard tilt angle for solar panels
The ideal tilt angle is one in which the annual power generation of the solar cell is as large as possible and the difference between winter and summer power generation is as small as possible. Generally, the local latitude or latitude plus a few degrees is used as the tilt angle of the local solar module installation.
Of course, if computer-aided design software can be used to optimize the calculation of the solar panel angle of azimuth, it would be better if both could be taken into account, which is particularly important for high latitudes. The amount of solar radiation at the water level in winter and summer varies greatly in high latitudes.
By choosing the optimal tilt angle, the difference between the amount of radiation in winter and summer on the solar cell is reduced, and the battery capacity(12v 100ah lithium ion batteries) can be reduced. Obtain an equilibrium, so that the cost of the system is reduced and the design is more reasonable. The optimal installation solar panel angle of different types of solar PV systems is different.
For example, in photovoltaic power generation systems powered by seasonal loads such as light-controlled solar street lighting systems, the working hours of such loads vary with the seasons, and they are characterized by the use of natural light to determine the length of the load's daily working hours.
In winter, the hours of sunshine are short, the solar radiation energy is small, and the night load works for a long time and consumes a lot of electricity. Therefore, the system design should take winter into account, and determine the solar panel angle of tilt that can obtain maximum power generation in winter.
The solar panel angle should be greater than the local latitude. For photovoltaic systems that mainly supply power to summer loads, such as photovoltaic pumps, refrigeration and air conditioning, it should be considered to provide maximum power generation for summer loads, and the solar panel angle should be smaller than the local latitude.
4. What is the benefit of tilting solar panels
Reduce the impact of shading on power generation.
In general, when we calculate the amount of electricity generated, we get it on the premise that there is no shadow on the surface of the solar panel. Therefore, if it cannot be directly illuminated by sunlight, then only scattered light is used to generate electricity, and the power generation at this time is about 10%-20% less than that without shadow.
The specific high efficiency solar panels design, while reasonably determining the solar panel angle, should also be considered comprehensively, so that the square array can reach the best state.
5. How to determine the angle and installation direction of the solar panel
Before we get into that, the first thing we should do is:
- Know how much solar radiation you have in your area.
- Familiarize yourself with the meteorological information of your location.
- Find the average daily radiation on the water level of the area over the last month.
- Adjust the light intensity of the panels to the minimum and maximum levels of solar radiation to make more efficient use of the panels' solar energy.
Secondly, a problem that cannot be ignored is that in different seasons and time periods, the peak isolation time in each direction is different. Then we should pay attention to the different incidences of sunlight in the hot summer and cold winter, and adjust the installation measures of the panel for different seasons.
At the same time, in order to make more efficient use of space and avoid obstruction of sunlight entering the process, tall buildings should be avoided when installing solar panels.
Installation direction: When the sunlight is facing the panel, the solar energy absorption per unit area of the panel is the largest, and it is best to face north in the southern hemisphere and face south in the northern hemisphere.
Mounting angle: The tilt angle of the panel is to allow solar energy to receive as much energy as possible, and the size of the tilt angle is related to the latitude you are at.
6. Precautions when installing solar panels
- Install photovoltaic panels to avoid shading as much as possible.
- Try to clean the dust and debris on the solar panels regularly. Otherwise, it is easy to cause heat island effect and affect power generation efficiency.
- Stability and firmness of the stent placement (taking into account local meteorological data, such as sunshine hours, severe weather, storms, etc.).
- Routing distance and combiner box location.
- Try to keep the distance short and even.
- The terminal should be secured to prevent false connections or breakages.
- The battery terminal(12 volt 200ah lithium battery) should be firm (never short circuited) and pay attention to the polarity when installing to avoid explosion and fire.
7. Conclusion
Because the Earth's axis of rotation and orbit are not perpendicular, the angle of the sun is different in different seasons, with a difference of ±23.4 degrees. The median angle of the sun occurs at the spring and autumn, and at noon, the angle of the sun is exactly equal to (90 degrees minus your latitude).
Taking it all together, the optimal solar panel angle of tilt for a year should be a little larger than the latitude you are at to reach the maximum you receive throughout the year.
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