Solar energy is the sun's nuclear fusion reactions within the continuous energy generated. Earth orbit Josh Reddick Jersey , the average solar radiation intensity 1367kwm2. Earth's equatorial circumference to 40000km, and thus calculated the Earth's energy was up to 173,000 TW. At sea level standard peak intensity 1kwm2, a point on the earth's surface 24h, the average radiation intensity 0.20kwm2, the equivalent of a 102,000 TW of energy, human survival depends on these energies Jose Canseco Jersey , including all other forms of Renewable Energy (Except for geothermal energy resources) Although the total amount of solar energy resources is the human equivalent of energy used by ten thousand times, but the solar energy density is low, and it vary, as time changes, which is facing the development and utilization of solar energy major problem. These characteristics make it solar integrated energy system in the role of subject to certain restrictions. Sun is a huge, long, endless energy. Although the solar radiation energy to the Earth's atmosphere is only the total radiation energy (about 3.75 ? 1026W) 2.2 billion to one, but up to 173 Joe Morgan Jersey ,000 TW, that sun exposure to the earth per second is equivalent to the energy 5 million tons of coal. The figure is the planet's energy flow diagram. As can be seen from the chart, earth wind energy, hydropower, ocean thermal energy, wave energy and biomass and some solar tidal energy comes from; even the earth of fossil fuels (such as coal, oil, natural gas ) basically said that since the store is down the ancient solar energy Jed Lowrie Jersey , it covered a broad range of solar energy is very large, narrow solar energy is limited to solar radiation, solar thermal, photovoltaic and photochemical direct conversion. Earth energy flow diagram (unit 106MW) Solar energy is an energy, is renewable energy. It is rich in resources, both free, then no transport, no pollution on the environment. However Jarrod Parker Jersey , there are two main solar disadvantages: First, energy density is low; Second, its strength due to various factors (season, location, climate, etc) can not maintain a constant effect. These two drawbacks greatly limit the effective use of solar energy. Human use of solar energy has a long history. In the early years of the Warring States period in 2000 knew of four steel mirror to focus sunlight ignition; use of solar energy to dry agricultural products. To the modern, solar energy has become increasingly widespread, it includes the use of solar light and heat Glenn Hubbard Jersey , solar photovoltaic and solar energy use photochemical utilization. 1.2 Structure of the Sun Sun is a hot gaseous sphere, its diameter is about 1.39 ? 106km, a mass of about 2.2 ? l027t, the quality of the Earth 3.32 ? 105 times larger than the earth in volume, 1.3 ? 106 times the average density of the Earth 1 4. The main component gases of hydrogen (about 80%) and helium (about 19%). Within the sun is going with hydrogen into helium fusion reaction polymerization, has continued to release tremendous amounts of energy, and in the way of radiation and convection heat transfer from the core to the surface temperature also decreased gradually from the center to the surface. Known by the nuclear fusion of hydrogen into helium in the aggregate, while the release of enormous energy Dennis Eckersley Jersey , the quality of the loss of 0.00729 per 1g. Under the current estimated rate of nuclear energy the sun produces its hydrogen reserves are sufficient to maintain 60 billion years, so solar energy can be unlimited. The structure shown above the sun. Radius of the sun an average of 23% (0.23R) in the region of the sun's core, its temperature is about 8 ? 106 ~ 4 ? 107K, the density of water of 80 ~ 100 times, accounting for 40% of the quality of the sun all, the total volume 15%. This part of the total solar energy generated 90% of the total energy generated. -ray polymerization of hydrogen release, when it is cold zone through the consumption of energy because the wavelength growth into X-ray or ultraviolet and visible light. From 0.23 ~ 0.7R area known as "radiation lose energy region", the temperature dropped to 1.3 ? 105K Dave Henderson Jersey , the density dropped to 0.079gcm3. 0.7 ~ 1.0R between the known as the "convective zone", the temperature dropped to 5 ? 103K , the density dropped to 10-8gcm3. The sun's outer layer is a light ball, it is the people the naked eye can see the sun's surface, the temperature of 5762K, a thickness of 500km, the density of 10-6gcm3, which is formed by the strongly ionized gas Coco Crisp Jersey , solar most of the radiation is thus launched into space. Light not only distributed the ball outside light and almost transparent solar atmosphere, called the "anti-change layer", which is composed of very thin air, hundreds of kilometers thick, it absorbs some of the visible spectrum of radiation . "Anti-change layer" is outside the upper solar atmosphere, called the "chromosphere", a thickness of 1 ~ 1.5 ? 104km, most composed of hydrogen and helium. "Chromosphere" is inserted into the space outside the silver-white corona Catfish Hunter Jersey , the temperature up to 1 million degrees, high and sometimes up to dozens of solar radius. The structure can be seen from the sun, the sun is not a black body temperature constant, but rather a multi-emission and absorption of different wavelengths of the radiator. But in the utilization of solar energy is usually regarded it as a temperature of 6000K, emission wavelength of 0.3 ~ 3 m in bold.