The earth can be regarded as a solid ball with an average radius of about 637 1km. Its structure is like a half-boiled egg, which is mainly divided into three layers. The appearance of the earth is equivalent to the eggshell, which is called the "crust". Its thickness varies from several kilometers to 70 kilometers, with the continental crust thicker and the marine crust thinner.
Below the crust is the "middle layer", which is equivalent to egg white, also called "mantle". It is mainly composed of molten magma with a thickness of about 2900 kilometers. The interior of the earth's crust equivalent to egg yolk is called the "core", and the core is divided into an outer core and an inner core.
In the history of the earth, the average heat generated by the decay of radioactive elements on the earth is 5 trillion calories (calories) per year. 198 1 In August, the United Nations New Energy Conference was held in Nairobi, Kenya. According to the technical report of the conference, the potential resources of global geothermal energy are equivalent to 450,000 times of the total global energy consumption.
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The role of geothermal energy:
1, geothermal heating
Using geothermal energy to directly heat, warm and make hot water is the second only to geothermal power generation. Because of its simple utilization mode and good economy, it is highly valued by all countries, especially the western countries located in the alpine region, among which Iceland is the best to develop and utilize. As early as 1928, the country built the world's first geothermal heating system in Reykjavik, the capital. Now, this heating system has developed very well, and it can extract 7740t80℃ hot water from underground every hour for the use of 1 10000 residents in the city.
2. Geothermal agriculture
Geothermal energy is widely used in agriculture. If the farmland is irrigated with geothermal water with suitable temperature, the crops can be matured and the yield can be increased. Using geothermal water to raise fish can accelerate the fattening of fish at 28℃ and increase the output of fish. Using geothermal energy to build greenhouses, raise seedlings, grow vegetables and flowers; Using geothermal energy to heat biogas digesters to increase biogas production.
Baidu encyclopedia-geothermal (energy resources)
Baidu encyclopedia-geothermal energy