Main points of solar cell module installation
◆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.
?Solar cell phalanx bracket
The solar cell array bracket is used to support the solar cell modules. The structural design of the solar cell array shall ensure that the solar cell module and the bracket are firmly and reliably connected, and the solar cell module can be easily replaced. The solar cell array and support must be able to withstand the wind of 120km/h without being damaged.
When installing the solar cell array bracket, its inclination (adjustable or fixed) should enable the solar cell array to obtain the maximum power generation in the design month (that is, the month with the worst average daily radiation). All the fasteners of the square array must have sufficient strength to reliably fix the solar cell module on the support. The solar cell array can be installed on the roof, but the bracket must be connected to the main structure of the building, not the roof material. For the solar cell array installed on the ground, the minimum distance between the solar cell module and the ground should be more than 0.3m. The bottom of the column must be firmly connected to the foundation so as to be able to bear the weight of the solar cell array and to withstand the design wind speed.
In the structural design of solar photovoltaic power generation systems, an issue that requires great attention is the design of wind resistance. According to the technical parameters of the solar cell module manufacturer, the upwind pressure that the solar cell module can withstand is 2700Pa. If the wind resistance coefficient is selected as 27m/s (equivalent to a tenth typhoon), according to the non-viscous fluid mechanics, the wind pressure on the solar cell module is only 365Pa. Therefore, the component itself can withstand the wind speed of 27m/s without being damaged. Therefore, the key considerations in the design are the design of the solar cell square array bracket, the basic design, and the connection design between the bracket and the foundation. The connection design of the solar cell phalanx bracket and the foundation should use bolts and rods to fix the connection.
The solar cell phalanx bracket must withstand environmental stresses such as wind and snow. The mounting holes must ensure easy installation and adjustment, and must withstand certain mechanical stress. The use of the correct mounting structure materials can reduce the corrosion of the module frame, mounting structure and materials to The smallest.
If the solar cell array is installed on the truss tower of the wind turbine, the solar cell array bracket should be reliably connected to the truss tower. The solar cell array bracket should be installed at a position more than 30cm away from the wind turbine blades. The battery holder is fixed with bolts. Before hoisting the truss tower, the output terminal voltage of the solar cell array should be tested, and the connection lines should be checked.
?Solar cell phalanx installation precautions
Choosing the location of the solar cell array carefully is the first step to complete the installation of the photovoltaic system. The electrical equipment should avoid unnecessary outdoor exposure, and the installation of electrical equipment should take into account that the system can be easily maintained. The solar cell array should be as close as possible to the storage battery and power conditioning equipment to shorten the line distance as much as possible to reduce line loss.
The solar cell array is expensive, light in weight, small in size, and easy to be stolen. For this reason, protection devices can be installed to improve the safety of the solar cell array. Use special screws to install the panel to prevent it from being quickly removed. An anti-theft door is installed in the passage leading to the fixed support frame to improve safety.
A simple, sturdy, and durable installation structure should be provided for the support frame of the solar cell module. The material used to manufacture and install the solar cell square array bracket must be able to withstand the erosion of wind and rain and various corrosions. Electroplated aluminum profiles, electroplated steel and stainless steel are all ideal choices. The solar cell phalanx bracket should be light in weight to facilitate transportation and installation. In the installation of many photovoltaic systems, wooden brackets and frames have been successfully applied. However, wood materials require more maintenance, so it is generally not recommended to use wood as the installation material for solar cell phalanx brackets.
