The basic ways of using solar energy can be divided into the following four categories.
(1) Light and heat utilization
Its basic principle is to collect solar radiant energy and convert it into heat energy through interaction with matter for use. Currently, the most commonly used solar collectors include three types: flat-plate collectors, evacuated tube collectors, and focused collectors. The International Energy Agency (IEA) divides solar thermal utilization into low-temperature utilization (40~100℃), medium-temperature utilization (100~400℃) and high-temperature utilization (400~800℃) according to different temperatures and uses that can be reached. ,. At present, low-temperature applications mainly include solar water heaters, solar dryers, solar distillers, solar houses, solar greenhouses, solar air-conditioning refrigeration systems, etc., medium-temperature applications mainly include solar cookers, solar thermal power generation, etc., high-temperature applications mainly include solar thermal power generation, high-temperature solar Furnace and so on.
(2) Solar power generation
The large-scale utilization of solar energy in the future is mainly used to generate electricity. There are many ways to use solar power to generate electricity, and currently there are mainly the following two practical ones.
① Light-heat-electricity conversion. That is to use the heat generated by solar radiation to generate electricity. Generally, a solar collector is used to convert the absorbed light energy into the heat energy of the working fluid steam, and then the steam drives the steam turbine to drive the generator to generate electricity. The former process is light-heat conversion, and the latter process is heat-electric conversion.
②Optical-electrical conversion. Its basic principle is to use the photovoltaic effect to directly convert solar radiant energy into electrical energy, and its basic device is a solar cell.
(3) Photochemical utilization
This is a photochemical conversion method that uses solar radiation energy to directly split water to produce hydrogen.
(4) Photobiological utilization
The process of converting solar energy into biomass is realized through photosynthesis of plants. At present, there are mainly fast-growing plants (such as firewood), oil crops and giant seaweeds.
The following article mainly introduces the use of solar light and heat and solar power generation, excluding photochemical use and photobiological use.