Solar panel is by absorbing sunlight, the solar radiation energy through photoelectric effect or photochemical effect directly or indirectly converted into electrical energy device, most of the solar panel's main material is "silicon", when the light hits the surface of the solar cell, part of the photons are absorbed by the silicon material; The energy of the photon is transferred to the silicon atom, which makes the electrons transition and become free electrons to gather on both sides of the P-N junction to form a potential difference. When the external circuit is connected, a current will flow through the external circuit to produce a certain output power under the action of the voltage. The essence of this process is: the process of converting photon energy into electric energy.
Solar panel power calculation
Solar ac power generation system is composed of solar panels, charging controller, inverter and battery. Solar DC power systems do not include inverters. In order to make the solar power system can provide enough power for the load, it is necessary to choose the components reasonably according to the power of electrical appliances. The following takes the 100W output power for 6 hours a day as an example to introduce the calculation method:
1. First of all, calculate the watt-hours consumed every day (including the loss of the inverter) : if the conversion efficiency of the inverter is 90%, then when the output power is 100W, the actual output power should be 100W/90%=111W; If it is used for 5 hours a day, the output power is 111W*5 hours =555Wh.
2. Calculation of solar panels: according to the daily effective sunshine time of 6 hours, and considering the charging efficiency and loss in the charging process, the output power of solar panels should be 555Wh/6h/70%=130W. Seventy percent of that is the actual power used by the solar panel during charging.
Solar panel power generation efficiency
Monocrystalline silicon solar energy has the highest photoelectric conversion efficiency of 24%, which is the highest in all kinds of solar cells. But monocrystalline silicon solar cells are too expensive to be widely and universally used. In terms of production cost, polycrystalline silicon solar cells are cheaper than monocrystalline silicon solar cells, but the photoelectric conversion efficiency of polycrystalline silicon solar cells is much lower, in addition, the service life of polycrystalline silicon solar cells is shorter than monocrystalline silicon solar cells. Therefore, monocrystalline silicon solar cells are slightly better in terms of performance/price ratio.
Researchers have found that a number of compound semiconductor materials are suitable for use as thin films for solar photovoltaics. Such as CdS, CdTe; ⅲ -V compound semiconductor: GaAs,AIPInP, etc. Thin film solar cells made of these semiconductors show good photoelectric conversion efficiency. Semiconductor materials with multiple gradient band gaps can enlarge the spectrum of solar energy absorption and improve the efficiency of photoelectric conversion. Therefore, a large number of practical applications of thin film solar cells show a broad prospect. Cu(In,Ga)Se2 is one of the most excellent solar absorbent materials. Based on it, thin film solar cells can be designed with a photoelectric conversion efficiency of 18%, which is significantly higher than that of silicon.
The life of a solar panel
The service life of solar panels is determined by the materials of cells, tempered glass, EVA, TPT and so on. Generally, the service life of solar panels made by manufacturers with better materials can reach 25 years, but with the impact of the environment, the material of solar panels will be aging with the change of time. In general, the power will decay by 30% after 20 years and 70% after 25 years.
