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Solar Energy. The Sun. 99.98 % of enegy from the sun 1/3 of the tide and flood caused by the sun’s gravitation Distance: 150 million kilometers. The Sun. 99,9 % of the mass of the solar system (1,989 x 10 30 kg) Temperature at the centre: 14,8 million K Surface temperature: 5.800 K
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The Sun • 99.98 % of enegy from the sun • 1/3 of the tide and flood caused by the sun’s gravitation • Distance: 150 million kilometers
The Sun • 99,9 % of the mass of the solar system(1,989 x 1030 kg) • Temperature at the centre: 14,8 million K • Surface temperature: 5.800 K • 73,5 % Hidrogen, 25 % Helium • Gravity 27 times higher than on earth • Ca. 4,5 billion years old
Energy generation in the Sun • Mainly proton-proton reaction • 564 mio t of hidrogen are burned to 560 mio t of Helium • Output power:3,7 x 1026 W • E=mc2
Structure of the Sun • Structure • Core • Radiation zone • Convection zone • Photosphere • Chromosphere • Corona
Lifecycle • 4,6 billions years ago: gravitational collaps • Today: main sequence evolution (halfway in ca. 10 billion years of H to He fusion) • In 0,9 billion years: earth temperature > 30°C • In 1,9 million years:earth temperature > 100°C • in 7 billion years: red giant, venus and mercury destroyed, earth surface molten • He to C fusion starts (ca 130 million years) • White dwarf (only 50 % of its original mass)
Solar spectrum • Solar constant (AM 0): 1354 W/m2 • AM 1: 1040 W/m2 • AM 1,5: 970 W/m2
Solar energy harvesting • Photovoltaic or Photothermal
Solar thermal energy harvesting Solar thermal energy harnessing • Passive: • Ventilation • Thermal mass • Active: • Heating • Cooling • electricity
Passive usage of Solar Energy: Ventilation • Solar chimney • Down Draft cool • tower
Passive usage of Solar Energy: heat mass • Simply heat mass for storing energy • Trombe wall
Active usage of solar energy:heating • Solar collectors: • Themosyphon • Low Flow System • High Flow System
Active usage of solar energy:heating Solar thermal collectors • Non concentrated: • Flat plate • Evacuated tubes • Concentrator type: • parabolic trough • parabolic dishes • heliostats • evacuated tubes
Non concentrated solar thermal collectors Evacuated tube collectors: Lower heat losses in cold periods, For water heating and auxilliary heating Flat plate collectors: simple, hot water generation and auxilliary heating, heat losses in cold perois
Concentrator type solar thermal collectors • High temperatures possible • Using coolants for heat • transfer (mostly some oil)
Active usage of solar energy:electricity • Always use concentrators (except photovoltaics) • Concentrated solar energy is used to produce steam • Normal steamturbine-generator power plants • Stirling motors
Solar power towers • Solar One in the USA • PS 10 Spain:using molten sodium
Solar power plants • SEGS: 354 MW(USA) • Andasol 1: 20 MW (Spain)