Talking about the main points of the installation of solar cell components in off-grid power generation systems
◆Solar cell detection
In order to judge whether the battery module is working properly, the solar cell should be tested before installation. The installer must compare the technical manual of the solar cell manufacturer during the measurement. The open circuit voltage measurement must be performed before the solar cell module is heated by sunlight, because the output voltage of the solar cell module will drop as the temperature rises. The measurement of short-circuit current is directly affected by the intensity of sunlight. Unless the intensity of sunlight can be accurately measured, only an approximate estimate can be made about the output current characteristics of the solar cell module. When measuring, make the solar cell module plane perpendicular to the sunlight. The field measurement results of most solar cell modules are within 5-10% of the data given in the product manual. It is best to measure the solar cell modules under the strongest conditions at noon. .
Installation method
1) Bracket installation method. A simple bracket device can be used to install a single solar cell array. Fix two angle-shaped galvanized steel brackets on the outer wall and roof of the building with screws, and connect the other pair of brackets to the ends of the solar cell module frame, and connect the two sets of brackets to form A simple, durable and inexpensive bracket device for installing solar cell arrays. The bracket device can be made rotatable, so as to adjust the inclination angle according to the season, so as to optimize the performance of the photovoltaic system.
2) Column installation method. Use a vertical column directly fixed on the ground to install the solar cell array. Generally speaking, a steel pipe with a diameter of 5 to 7 cm is very suitable as a material for this support structure. With this installation method, the inclination angle can also be adjusted according to the season to optimize the performance of the photovoltaic power generation system.
3) Ground installation method. When installing the solar cell array on the ground, you should make a base on the ground in advance, then fix the metal frame on the base, and finally install the solar cell array on the frame. The installation frame usually consists of two parallel trough beams. Use screws to fix the horizontal supporting aluminum profile on the trough beam. The horizontal supporting aluminum profile must have a high strength to prevent it from being damaged by the wind. Fix the aluminum frame of the solar cell array with screws on the upper and lower horizontal support aluminum profiles (should be fixed at the pre-measured inclination angle). You can also buy or make a bracket device that can adjust the inclination angle to adjust the inclination angle of the battery panel according to the season. Since the lime component in concrete will corrode aluminum materials, the metal frame directly installed on the concrete base should use galvanized steel.
In addition, screws, nuts and washers should be made of stainless steel to prevent corrosion. Before the final selection of the installation location of the solar cell array, it is necessary to evaluate the local climatic conditions and the pressure-bearing capacity of the soil in detail. The ground installation method requires a sufficiently strong base to avoid damage due to excessive pressure. The base must also withstand the tangential (lateral movement) force caused by the wind. Reference to local building standards can provide a basis for determining the foundation requirements. Before installation, ensure that the above-mentioned supporting members meet these standards.
4) Roof installation method. There are four common methods for installing solar cell arrays on the roof: bracket installation, independent installation, direct installation, and integrated installation.
① Bracket installation. In the bracket installation method, the solar cell array is supported by a metal frame and presents a preset inclination angle. For the solar cell array installed with brackets, the brackets are fixed on the roof with screws. This installation method will increase roof load-bearing and wind stress issues. However, since the airflow path completely surrounds the solar cell array, the solar cell array can maintain a relatively low operating temperature, thereby improving efficiency. Some bracket installation methods can adjust the inclination angle according to the season to improve the efficiency of the photovoltaic power generation system.
② Independent installation. The independent installation method is to install the solar cell array directly on the frame on the roof. The frame is parallel to the inclination of the roof and is 10-20cm high from the roof. The supporting crossbars are fixed on independent frames, and the solar cell array is fixed on these crossbars. The advantage of the independent installation method is that it provides a free flow path for the solar cell array. The disadvantage of the independent installation method is that it is difficult to maintain the solar cell array and replace the roofing materials.
③Install directly. Direct installation means that the solar cell modules are directly installed on the cover of the ordinary roof, so there is no need for supporting frames and cross bars. The phalanx of solar cells must maintain the integrity of the roof covering seal, so the roof must be sealed with a suitable sealant frequently. The air flow of the direct installation system cannot flow around the solar cell array, which results in the solar cell array operating temperature in this installation method being approximately 20°C higher than other installation methods. Since the electrical connection of the solar cell array cannot be fully observed, this brings difficulties to inspection and maintenance.
④Integrated installation. The integrated installation method is to install the solar cell array directly on the rafters on the roof, and replace the conventional roof covering with the solar cell array. The solar cell array is sealed with glazed butyl synthetic rubber or gasket material equipped with metal slats. This installation method is suitable for occasions where the roof orientation and inclination are illuminated by sunlight. This installation method is easy to ventilate, so it can ensure that the solar cell array runs at an efficient working temperature. Since the solar cell phalanx connection lines are exposed in the attic, it is easy to check and repair the lines.
