It must carry a 30W load, operate 6 hours per day and consume 1,360 Wh of electricity per week. The solar panel absorbs energy and requires losses, and the conversion efficiency is 80-95%. and the loss during the charging process, this loss in the process is 60% to 75%. If there are no rainy days and the light is counted for 8 hours per day, the load is approximately 38W taking into account 3 rainy days. days per week, you have to multiply it by 4/3, or 51.4w, it is almost enough to choose 50w.
What is the best direction for solar panels?
1. Classification of solar cells:
Solar cells currently on the market are divided into amorphous silicon and crystalline silicon. Crystalline silicon can be divided into polycrystalline silicon and monocrystalline silicon. Judging from the photoelectric conversion efficiency of the three materials: silicmonocrystalline silicon (up to 17%) > polycrystalline silicon (12 to 15%) > amorphous silicon (around 5%). However, crystalline silicon (monocrystalline silicon and polycrystalline silicon) basically does not generate current under low light, and amorphous silicon is good under low light (it has very little energy under low light). Therefore, from an overall point of view, it is suitable to use monocrystalline silicon or polycrystalline silicon solar cell materials.
Second, the selection method of solar cells
1 When we purchase solar cells, the focus is on the power of solar cells. Generally speaking, the power of solar panels is the same. like the power of solar cells. Directly proportional to the surface area of the solar panel. The surface area of the solar cell wafer is not completely equal to the surface area of the solar package panel, because biAlthough some solar panels are large, the gaps between single solar panels are very wide and the power of these solar panels is not necessarily high.
Knowledge about purchasing solar batteries
2. Generally speaking, the greater the power of the solar panel, the better. In this way, the current generated by sunlight is large, and it is large. can be integrated quickly. The battery is fully charged. But in reality, you have to find a balance between the power of the solar panel and the portability of the solar charger. It is generally believed that the minimum power of a solar charger cannot be less than 0.75W, and an under-power solar panel can produce 140mA current under standard strong light. The current generated under sunlight is about 100mA. If the charging current is too low below the underpower, there will basically be nono obvious effect.
It is preferable that the solar panels face south.
Solar panels must face the sun and benefit from maximum sunlight. The azimuth angle of the panels on common solar street lights in life is generally chosen to be in the south direction, which can optimize the power output of solar panels per unit time if the solar street lights are installed in places such as roofs. slopes, mountains and building structures. When considering restrictions on shadows, etc., you should consider how to make full use of the existing land and effective area, and try to avoid shadows generated by surrounding buildings, structures or trees.
As long as it is ±20° due south, it will not have a big impact on electricity production. If conditions permit, it should be as far away asue possible less than 20° southwest to allow the peak. of solar energy production will appear at noon. A little later, this will allow more electricity to be produced in winter. When the installation area of solar panels in the south direction is not large enough, the solar panels can also be installed in the east and west directions.
Selection of the tilt angle of the solar panels:
The ideal tilt angle is to make the annual energy production of the street lighting solar panels as large as possible, so that in winter The difference in electricity production between summer and summer is as small as possible. Generally, local latitude or local latitude plus a few degrees is used as the tilt angle for local installation of solar cell module. (Generally, the tilt angle is 30 degrees in areas south of the riverYangtze and 45 degrees in areas north of the Yangtze River.)
Of course, if computer-aided design software can be used, the A tilt angle optimization calculation solar can be done, it would be better to be able to take both into account, which is particularly important for high latitudes. There is a very large difference in horizontal solar radiation between winter and summer at high latitudes.
If the design is based on horizontal plane radiation parameters, the storage capacity of the battery in winter will be too large, resulting in an increase in the design capacity and investment of the battery. battery. By choosing the optimal tilt angle, the difference between winter and summer radiation on the solar panel becomes smaller and the battery capacity can also be reduced. A balance is found, which reduces the cost of the entire ssolar public lighting system. the design more reasonable.