Tell me what you think of solar energy.

Solar energy is the energy generated by the continuous nuclear fusion reaction inside the sun. The average solar radiation intensity in Earth orbit is 65,438+367 kW/m2. The circumference of the equator of the earth is 40000km, so it can be calculated that the energy obtained by the earth can reach 173000 tw. The standard peak intensity of sea level is 1kw/m2. The 24-hour annual average radiation intensity at a certain point on the earth's surface is 0.20kw/m2, which is equivalent to the energy of 102000 tw. Human beings depend on this energy for survival, including all other forms of renewable energy (except geothermal energy resources). Although the total amount of solar energy resources is more than 1 10,000 times of the energy currently used by human beings, the energy density of solar energy is low, and it varies from place to place and from time to time. This is the development and utilization of solar energy.

The sun is a huge, ancient and endless energy source. Although the energy radiated by the sun to the earth's atmosphere is only 2.2 billion times of its total radiation energy (about 3.75× 1026W), it reaches 173000 tw, which means that the energy radiated by the sun to the earth every second is equivalent to 5 million tons of coal. The picture below shows the energy flow map on the earth. Even the fossil fuels on the earth (such as coal, oil, natural gas, etc. ) are basically solar energy stored since ancient times, so the broad sense of solar energy is very wide, while the narrow sense of solar energy is limited to the direct conversion of solar radiation into photothermal, photoelectric and photochemical energy.

Solar energy is not only a primary energy, but also a renewable energy. Rich in resources, can be used for free without transportation, and has no pollution to the environment. But solar energy also has two main disadvantages: first, the energy flow density is low; Second, its intensity cannot be kept constant due to various factors (season, place, climate, etc.). ), which greatly limits the effective use of solar energy.

Humans have a long history of using solar energy. As early as more than 2,000 years ago during the Warring States Period, China knew to use a steel four-sided mirror to focus the sunlight and ignite it. Using solar energy to dry agricultural and sideline products. With the development of modern times, the utilization of solar energy is increasingly extensive, including photothermal utilization, photoelectric utilization and photochemical utilization of solar energy.