Solar Energy
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Transcript of 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 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 thermal energy harvesting
Solar thermal energy harnessing
Active:- Heating- Cooling- electricity
Passive:- Ventilation- Thermal mass
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
Flat plate collectors: simple, hot water generation and auxilliary heating, heat losses in cold perois
Evacuated tube collectors:Lower heat losses in cold periods,For water heating and auxilliary heating
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