Solar thermal energy ppt

solar thermal energy powerpoint presentation and solar thermal energy conversion ppt
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HelenBoyle,Greece,Researcher
Published Date:14-07-2017
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Solar Thermal Energy Prof. Keh-Chin Chang Department of Aeronautics and Astronautics National Cheng Kung University The Sun Source of Solar Energy  A sphere of intensely hot gaseous matter Consist of H, He, O, C, Ne, Fe… Surface temperature: 5,800K Core temperature:13,600,000K Between the Sun and the Earth Source of Solar Energy Average distance:149.5 million km (1 astronomical unit, AU) equinox solstice solstice Elliptic Orbit equinox Between the Sun and the Earth Source of Solar Energy Position of the Sun (view from Earth) Source of Solar Energy Apparent placement of the Sun in the northern hemisphere Position of the Sun (view from Earth) Source of Solar Energy Azimuth angle of the sun: Often defined as the angle from due north in a clockwise direction. (sometimes from south) Zenith angle of the sun: Defined as the angle measured from vertical downward. Solar Constant Source of Solar Energy  Amount of incoming solar radiation per unit area incident on a plane perpendicular to the rays.  At a distance of one 1AU from the sun (roughly the mean distance from the Sun to the Earth).  Includes a range of wavelength (not just the visible light). Solar Constant Entry point into atmosphere 2 Intensity 1350W/mSolar Radiation Spectrum Source of Solar Energy Solar Radiation Budget (to Earth) Source of Solar Energy Factors affect the Solar intensity Source of Solar Energy  Latitude  Altitude  Atmospheric transparency  Solar zenith angle Applications of Solar Energy  Reserves of energy on Earth  Solar energy distribution  Advantages of using solar energy  Types of applications Reserves of Energy on Earth Applications of Solar Energy Remaining Available Period Reserves (year) Coal 660.8 Gton 43 Oil 152 Gton 210 3 Gas 160755 Gm 67 Uranium 1.57 Mton 42 Solar Energy Distribution Applications of Solar Energy Annual global mean downward solar radiation distribution at the surface Advantages of using Solar Energy Application of Solar Energy  No pollution  Inexhaustible  Contribution to energy supply and CO reduction 2  The annual collector yield of the world was 109,713 GWh (394,968 TJ). This corresponds to an oil equivalent of 12.4 million tons and an annual avoidance of 39.4 million tons of CO . 2  The annual collector yield of Taiwan was 918 GWh (3306 TJ). This corresponds to an oil equivalent of 101,780 tons and an annual avoidance of 322,393 tons of CO . 2 Weiss, Werner, I. Bergmann, and G. Faninger. Solar Heat Worldwide–Markets and Contribution to the Energy Supply 2008. International Energy Agency, 2010. Advantages of using Solar Energy Application of Solar Energy  Energy production prediction Types of Applications Application of Solar Energy  Photovoltaic (PV)  Solar cell  Solar thermal energy  Solar water heater  Solar thermal power  Solar cooling  Solar thermal ventilation Introduction to Heat Transfer  Heat Transfer in a Solar Collector  Heat Transfer Modes  Conduction  Convection  Radiation Heat Transfer Processes in a Solar Collector qconv,air qemit qsun absorbing film qconv,mediu Medium flow m qcond,insulator Insulator qcond,panel Panel(metal) Heat transfer modes Three heat transfer modes in a solar collector:  Radiation  𝑞 : solar irradiation 𝑛𝑢𝑠  𝑞 : emitted radiant energy from the panel 𝑒𝑖𝑚𝑡  Convection  𝑞 : heat loss due to wind 𝑣𝑐𝑜𝑛 ,𝑎𝑖𝑟  𝑞 : heat transfer to the flow medium 𝑣𝑐𝑜𝑛 ,𝑒𝑚𝑑𝑚𝑖𝑢 throughout tube wall  Conduction  𝑞 : heat transfer inside the metal panel 𝑑𝑐𝑜𝑛 ,𝑒𝑝𝑎𝑙𝑛  𝑞 : heat loss to the insulator from the panel 𝑑𝑐𝑜𝑛 ,𝑙𝑎𝑢𝑡𝑜𝑟𝑠𝑖𝑛Conduction Definition: The transfer of energy from the more energetic to the less energetic particles (atoms or molecules ) of a substance due to interactions between the particles without bulk motion. 𝑞 =𝑞 " ∙𝐴 𝑛𝑐𝑜𝑑 𝑛𝑐𝑜𝑑 heat flux area gradient Fourier’s Law: 𝑞 " =−𝑘 𝑛𝑐𝑜𝑑 thermal conductivity 𝛻𝑇