Sunlight shines on the semiconductor pn junction, bai f […]
Sunlight shines on the semiconductor pn junction, bai forms a new hole du hole-electron pair. Under the action of the pn junction electric zhi field, the holes flow from the daon area to the p area, and the electrons flow from the p area to the n area. After the circuit is turned on It forms an electric current. This is the working principle of photovoltaic effect solar cells. 1. Solar power generation There are two methods of solar power generation, one is light-heat-electric conversion, and the other is light-electric direct conversion. (1) The light-heat-electric conversion method uses solar radiation to generate heat to generate electricity. Generally, a solar collector converts the absorbed heat into vapor of the working fluid, and then drives a steam turbine to generate electricity. The former process is a light-heat conversion process; the latter process is a heat-electric conversion process, which is the same as ordinary thermal power generation.
The disadvantages of solar thermal power generation are its low efficiency and high cost. It is estimated that its investment is at least higher than that of ordinary thermal power generation. The power station is 5-10 times more expensive. A 1,000MW solar thermal power station requires an investment of 2 to 2.5 billion US dollars, and the average investment for 1 kW is 2000 to 2500 US dollars. Therefore, it can only be applied to special occasions on a small scale at present, and large-scale utilization is very economically uneconomical and cannot compete with ordinary thermal or nuclear power plants. (2) Light-to-electricity direct conversion method This method uses the photoelectric effect to directly convert solar radiant energy into electrical energy. The basic device of light-to-electricity conversion is solar cells. A solar cell is a device that directly converts sunlight energy into electrical energy due to the photovoltaic effect. It is a semiconductor photodiode. When the sun shines on the photodiode, the photodiode will turn the sun’s light energy into electrical energy to produce Current. When many batteries are connected in series or in parallel, it can become a square array of solar cells with relatively large output powerChina Solar Surface Pumps Suppliers. Solar cells are a promising new type of power source, with three major advantages: permanence, cleanliness and flexibility. Solar cells have a long life, as long as the sun exists, solar cells can be invested in one time and used for a long time; and thermal power generation, nuclear power generation In contrast, solar cells do not cause environmental pollution; solar cells can be large, medium and small, ranging from medium-sized power stations of a million kilowatts to small solar battery packs for only one household. This is a raw material for solar panels that other power sources cannot match: Glass, EVA, battery sheet, aluminum alloy shell, tin-clad copper sheet, stainless steel bracket, battery, etc.
Solar water heaters convert sunlight energy into heat energy and heat water from low temperature to high temperature to meet people's hot water use in life and production. Solar water heaters are composed of heat collection tubes, water storage tanks and related accessories. The conversion of solar energy into heat energy mainly relies on heat collection tubes. The temperature of the heat collector exposed to sunlight is high, and the temperature of the back surface of the heat collector tube is low, and the water in the tube produces a temperature difference reaction. Using the principle of hot water floating up and cold water sinking, the water generates microcirculation to reach the required hot water.
The working principles of solar panels and solar water heaters are quite different, the only thing in common is that they both absorb solar energy