Solar energy is a renewable energy source. Solar energy is generated by the fusion of hydrogen and helium inside the sun to release huge nuclear energy. It is the radiant energy from the sun. With the decline of fossil fuels, solar energy has been called an important part of renewable energy used by mankind, an important green energy material. The advantages of solar energy are: (1) Abundant resources, the annual solar radiant energy on the surface of the earth is equivalent to about 130 trillion tons of coal, the total amount of which is the largest energy source that can be developed today; (2) Clean energy, unlike fossil fuels such as coal, oil, and natural gas, solar energy does not pollute the environment; (3) It is easy to use, there is no geographical restriction on solar energy, and there is no need for mining and transportation. There are mainly two ways of using solar energy: light-to-heat conversion and photoelectric conversion.
- Solar cell: The photovoltaic conversion method of solar energy is currently the most widely used method. Solar cells can directly convert sunlight energy into required electrical energy. In aerospace, the use of solar energy can ensure the normal operation of spacecraft, and the application of solar cells on aircraft can save a lot of space and reduce load. In terms of automobiles, the application of solar cells can solve the problem of battery life of electric vehicles. In terms of communications, solar energy can be applied to solar signal transmission towers, solar wireless emergency telephones and other fields. In terms of transportation facilities, street lights and signal lights can be powered by solar energy or stored electricity to reduce the use of electrical energy. In terms of building facilities, solar cells can be used on the roof and curtain walls of buildings to provide electrical energy for the TV, refrigerator, lighting facilities and other electrical appliances in the house.
- Heating in agricultural greenhouses: The application of greenhouses in agriculture makes good use of light and heat conversion. Greenhouses can significantly increase crop yields and productivity. In the cold winter, the temperature in the solar greenhouse is relatively low, which cannot meet the normal growth of crops. The scientific and reasonable use of solar energy can effectively improve the temperature in the greenhouse in winter. For example, the solar energy cross-season heat storage heating system, using water as the medium, can indirectly store the excess solar energy resources in other seasons underground. Then the hot water is discharged in winter to increase the temperature of the soil heat source in the winter greenhouse to meet the growth temperature required by the plants, and to give full play to the role and advantages of solar energy.
- Ying Zhang, Muttucumaru Sivakumar, Shuqing Yang, Keith Enever, Mohammad Ramezanianpour. Application of solar energy in water treatment processes: A review [J]. Desalination, 2018, 428(15), 116-145.