一、The right way to install solar PV panels
1. Before installation, you first need to clarify the positive and negative poles of the photovoltaic panels, and connect them in series. Don't be mistaken, otherwise it will lead to a failure to charge, and in severe cases, it will burn the battery panel, greatly shorten the service life, and even the danger of explosion.
2. Next, you need to arrange the wire, try to choose the insulating copper wire, and the color is preferably different, so as to facilitate the installation. To install the wires in place, the joints need to be wrapped with insulating tape.
3. Then determine the direction of solar photovoltaic panel installation, and the direction is preferably due south to meet the requirements of light. Finally, adjust the angle of inclination, if it is close to the south, the angle can be set to a smaller one. For example, if the latitude is 0 to 25 degrees, the elevation angle can be set at about 25 degrees. If the latitude reaches between 26~40 degrees, add 5 degrees or 10 degrees to the surface on the basis of 25 degrees.
二、What are the photovoltaic solar installation tips??
1. Between the installation of photovoltaic solar energy, first use a right angle ruler to fix the tail of the rafters, and then move the secondary angle to the edge of the roof and make a mark on the position with chalk, preferably visible at the top of the roof, which is convenient for installation. In addition, when using this measurement method, it is necessary to rely on the rafters, and it is necessary to estimate the position of the rafters, preferably in a triangle and perpendicular to the rafters. If the roof has a particularly close backplate, you can see that there are many nails on the joists at the edges, which makes it possible to find out the approximate location of the rafters.
2. After you have measured the general position of the eaves, you can use a variety of methods to study how to install photovoltaic solar energy more conveniently. One of the easiest ways to do this is to use a lubricated dough hammer (a cowhide hammer can also be used) to strike it perpendicular to the rafters until you hear a very hard sound. Mark the location within a few feet of the very center of the rafters. You can also drill a few small holes in the left or right side of the rafters until you hit the center of the rafters. Another method is to use a high-density electronic sensor on a high-range device, carefully slide the device over a thin piece of cardboard (which can slide along the roof shingles) and you will see the end and end of the rafters.
3. When the approximate location of the rafters is known, the tiles can be moved around the installation of photovoltaic solar energy. Finally, follow the same order as above.
4. It is best to mark a hole in chalk after you have determined the center of the rafters.
三、Solar power generation installation technology
Solar power generation is a device that uses battery modules to directly convert solar energy into electricity. Solar cells are solid devices that use the electronic properties of semiconductor materials to achieve P-V conversion, and in the vast area without power grid, the device can easily realize power supply for user lighting and life, and some developed countries can also be connected to the regional grid to complement each other. At present, from the perspective of civil use, the foreign technology research tends to mature and is beginning to take shape in the integration of photovoltaic-building (lighting) technology, while the domestic main research and production of small solar power generation systems suitable for household lighting in areas without electricity.
1 Principles of solar power generation
The solar power generation system mainly includes: solar cell components (arrays), controllers, batteries, inverters, users, lighting loads, etc. Among them, the solar module and battery are the power supply system, the controller and inverter are the control and protection system, and the load is the system terminal.
1.1 Solar power system
Solar cells and batteries form the power supply unit of the system, so the performance of the battery directly affects the working characteristics of the system.
(1) Battery Unit:
Due to technical and material reasons, the power generation of a single cell is very limited, and the practical solar cell is a battery system composed of a single cell in series and parallel, called a battery assembly (array). A single cell is a silicon crystal diode, according to the electronic characteristics of semiconductor materials, when sunlight hits the P-N junction composed of two different conductive types of homogeneous semiconductor materials of P type and N type, under certain conditions, solar radiation is absorbed by the semiconductor material, producing non-equilibrium carriers that are electrons and holes in the conduction band and valence band. There is a strong built-in electrostatic field in the P-N junction barrier region, so that the current density J, short-circuit current Isc, and open-circuit voltage Uoc can be formed under illumination. If the electrodes are drawn out on both sides of the built-in electric field and connected to the load, theoretically speaking, the loop formed by the P-N junction, the connecting circuit and the load, there is a photogenerated current flowing through, and the solar module realizes the power P output to the load.
Theoretical studies have shown that the peak power Pk of solar modules is determined by the local average solar radiation intensity and the power load (electricity demand) at the end.
(2) Electric energy storage unit:
The direct current generated by the solar cell enters the battery storage first, and the characteristics of the battery affect the efficiency and characteristics of the system. Battery technology is very mature, but its capacity is affected by the power demand at the end and the sunshine time (power generation time). Therefore, the watt-hour capacity and ampere-hour capacity of the battery are determined by the predetermined continuous sunshine-free time.
The main function of the controller is to keep the solar power generation system near the maximum power point of power generation at all times to obtain the highest efficiency. The charging control usually adopts pulse width modulation technology, that is, PWM control mode, so that the whole system always runs in the area near the maximum power point Pm. Discharge control mainly refers to the cut-off switch when the battery is short of power and the system fails, such as the battery is open or reversed. At present, Hitachi has developed a sunflower controller that can track both the control point Pm and the sun's movement parameters, which improves the efficiency of fixed battery components by about 50%.
1.3 DC-AC inverter
According to the excitation mode, the inverter can be divided into self-excited oscillation inverter and other excited oscillation inverter. The main function is to convert the DC of the battery
Electricity inverts into alternating current. Through the full-bridge circuit, the SPWM processor is generally used to obtain the same illumination through modulation, filtering, boosting, etc
Matching sinusoidal alternating current such as clear load frequency f and rated voltage UN is used by the end user of the system.
Efficiency of solar power generation systems
In a solar power generation system, the total efficiency of the systemη ese consists of the PV conversion rate of the cell module, controller efficiency, battery efficiency, inverter efficiency and load efficiency. However, compared with solar cell technology, it is much more mature than the technology and production level of other units such as controllers, inverters and lighting loads, and the conversion rate of the current system is only about 17%. Therefore, improving the conversion rate of battery modules and reducing the cost per unit power are the key and difficult points of solar power industrialization. Since the advent of solar cells, crystalline silicon has maintained its dominance as the protagonist material. At present, the research on the conversion rate of silicon cells mainly focuses on increasing the energy-absorbing surface, such as bifacial cells, to reduce reflection; The use of impurity absorption technology to reduce the composite of semiconductor materials; Ultra-thin battery; Improve theory and establish new models; concentrating cells, etc. The conversion efficiency of several solar cells is shown in Table 1.
Table 1 Conversion efficiency of several solar cells
Laboratory typical battery Commercial thin-film battery
Various solar cells ηmax(%) Various solar cells η(%)
Monocrystalline silicon 24.4 Polysilicon 16.6
Polysilicon 18.6 Copper indium gallium selenide 18.8
GaAs (single junction) 25.7 cadmium telluride 16.0
A-Si (single junction) 13 Copper indium selenium 14.1
Making full use of solar energy is one of the important contents of green lighting. The real sense of green lighting at least includes: high efficiency of the lighting system, high stability, efficient and energy-saving green light source.
3.1 Power generation - integration of architectural lighting
At present, the solar modules and building components have been successfully integrated, such as solar roofs (roofs), walls, doors and windows, etc., to achieve photovoltaic-architectural lighting integration (BIPV). In June 1997, the United States announced the Solar Million Roof program, named after the president, to implement solar power systems for 1 million homes by 2010. Japan's New Sunshine Project has reduced the installed cost of photovoltaic building modules to 170~210 yen/W before 2000, the annual output of solar cells reaches 10MW, and the battery cost is reduced to 25~30 yen/W. On May 14, 1999, Germany built the world's first zero-emission solar module plant in only one year and two months, providing electricity entirely from renewable energy and emitting no CO2 in production. The south wall of the factory is about 10m high PV array glass curtain wall, including roof PV components, the entire factory building is equipped with 575m2 of solar modules, which alone can provide more than one-third of the building's electric energy, and its wall and roof PV component shape, color, architectural style and building combination, and the integration with the surrounding natural environment has reached a perfect coordination. The building has an additional capacity of about 45kW and is provided by a thermal power plant fueled by canola oil in its natural state, and is designed to produce a truly zero-emission plant that balances the CO2 produced when burning rapeseed oil and the CO2 required for rapeseed growth. BIPV also pays attention to the research of architectural decorative arts, and in the Czech Republic by the German company WIP and the Czech Republic to build the world's first color PV curtain wall. In the Indian state of West Bengal, 117 villagers on an island without electricity were installed with 12.5kW BIPV. Domestic Changzhou Tianhe Aluminum Curtain Wall Manufacturing Co., Ltd. successfully developed a solar room, the power generation, energy saving, environmental protection, value-added integration into one room, successfully combined photoelectric technology with building technology, called solar building system (SPBS), SPBS has passed the expert demonstration on September 20, 2000. Recently, the first solar-lighting integrated public toilet in Shanghai Pudong was built, and all electricity is provided by rooftop solar cells. This will effectively promote the industrialization and marketization of energy conservation in solar buildings.
3.2 Research on green lighting sources
The optimized design of the green lighting system requires high light efficiency output with low energy consumption and extended lamp life. Therefore, the DC-AC inverter design should obtain a reasonable filament warm-up time and the voltage and current waveforms of the excitation lamp.
At present, there are four typical circuits for the excitation of solar lighting sources in research and development:
(1) Self-excitation push-pull oscillation circuit, preheating and starting through filament series starter. The main parameters of the light source system are: input voltage DC=12V, output light efficiency > 495Lm/piece, lamp rated efficiency 9W, effective life 3200h, continuous opening times > 1000 times.
(2) Self-excited push-pull oscillation (simple type) circuit, the main parameters of the light source system are: input voltage DC=12V, lamp power 9W, output light efficiency 315Lm/branch, continuous start times > 1500 times.
(3) Self-excited single-tube oscillation circuit, filament series relay preheating start mode.
(4) Self-excited single-tube oscillation (simple) circuit and other high-efficiency energy-saving green light source.
IV. Concluding remarks
The issue of green energy and sustainable development is a major issue facing mankind in this century, and the development of new energy and the full and rational use of existing energy have received great attention from all governments. As an inexhaustible clean and environmentally friendly energy source, solar power generation will be developed unprecedentedly. With the deepening of solar energy industrialization process and technology development, its efficiency and cost performance will be improved, and it will be widely used in various fields including BIPV, and will also greatly promote the rapid development of China's green lighting projects.
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