In the previous article “Azimuth and tilt angle of solar cell array”, the relationship between the azimuth angle, the inclination angle and the power generation is described. For the specific design of the azimuth angle and the inclination angle of a solar cell array, it should be further considered in combination with the actual situation:
1) Continuity. The total amount of solar radiation in a year generally changes continuously, most of which rise and fall monotonically, and there are some fluctuations in some cases, but generally they do not fluctuate greatly.
2) Uniformity. Choosing the inclination angle, it is best to make the average daily radiation received on the surface of the square array relatively uniform throughout the year, so as to avoid excessive radiation received in summer and cause waste;
In winter, the amount of radiation received is too small, resulting in over-discharge and damage to the battery, reducing the life of the system and affecting the stability of the system.
3) Greatness. When choosing the inclination angle, not only should the solar cell array surface obtain the maximum radiation in the month with the weakest radiation, but also the annual average daily radiation should not be too small.
At the same time, a specific analysis should be made for specific situations. Generally, in southern China, the inclination angle of the solar cell array can be increased by 10°~15° compared with the local latitude; in the northern region, the inclination angle can be increased by 5°~10° compared with the local latitude. When the latitude is larger, the increased angle can be smaller.
In the Qinghai-Tibet Plateau, the inclination angle should not be too large, and can be roughly equal to the local latitude. At the same time, in order to facilitate the design and installation of the solar cell square array support, the inclination angle of the square array is often taken as an integer.
In the northern hemisphere, the solar cell arrays are uniformly oriented due south, and the angle of the inclined horizontal plane varies with latitude and longitude. When designing the inclination of the solar cell array, the main consideration is to make the solar cell array fully receive sunlight in spring, summer, autumn and winter. Especially in winter, the light intensity in winter is weak, and the angle will not be the same as in spring, summer and autumn. Therefore, when designing the angle of the solar cell array, special attention should be paid to the characteristics of solar illumination in winter. In addition, when designing the capacity of the solar cell module, it is best to leave a surplus capacity, so that the entire solar LED lighting system will work more stably. The design angle of the solar cell array is to find out the longitude and latitude of the location where the solar cell module is used, and design it according to the following conditions:
1) When the latitude is 0°~25°, the tilt angle of the solar cell module is the same as the latitude.
2) When the latitude is 26°~40°, the tilt angle of the solar cell module is latitude + (5°~10°).
3) When the latitude is 41°~55°, the tilt angle of the solar cell module is latitude + (10°~15°).
4) When the latitude>55°, the inclination angle of the solar cell module is latitude+(15°～20°).
For solar LED lighting systems, once the installation is completed, the inclination and azimuth of the solar cell array cannot be changed. In the solar LED lighting system with a tracking device installed, the solar cell array can track and move with the operation of the sun, so that the solar cells are always facing the sun, which increases the amount of solar radiation received by the solar cell array. However, relatively few tracking devices are currently used in solar LED lighting systems, because the tracking devices are complex, and the initial cost and maintenance cost are high. The benefits of installing the tracking devices to obtain additional solar radiation cannot offset the cost of installing the system.
For solar cell arrays, it is usually required to face the equator and be installed obliquely. When the solar cell phalanx is placed obliquely, the solar radiation received on the phalanx in winter months should increase to a certain extent, and the solar radiation received in summer months should be weakened to a certain extent, so that the whole year tends to be balanced, which is beneficial for battery charging. Therefore, in the solar LED lighting system, the square array of solar cells should be installed obliquely, and the optimal value of the inclination angle should be selected according to the different places of use.