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Similar to Chapter 2 Solar Radiations.pdf Chapter 2 Solar Radiations.pdf
Chapter 2 Solar Radiations.pdf Chapter 2 Solar Radiations.pdf
- 1. Solar Radiations 1 2/16/2023 WCE,Sangli • Sun is composed of 73% hydrogen, 25% helium and 2% other elements (02, CO2, N) • Hydrogen converted into Helium => Fusion process • Four Hydrogen atoms combine to give one molecule of Helium • Large amount of energy • Sun surface temp= 57600K • Earth receives energy from the sun, which is necessary to sustain life on the earth • Electromagnetic radiations wave length range => 10-6 μm to 1000 μm • sun radiation wavelength => 0.15 μm to 120 μm
- 2. Solar Radiations • Irradiance:( Power density) refers Rate of energy received by a surface per unit area. It is flux of solar energy • Unit of Irradiance : watts/ sq.meter = J/ Sq. meter. Sec • Irradiation or Insolation: Energy density : Amount of energy received by a surface area over the given period of time. • Integrated Irradiance over a period of time • Insolation is Long term average intensity of solar radiations. units W/sq.m 2/16/2023 WCE, Sangli 2
- 3. Solar spectrum atearths Surface • Earth continuously receives about 174X1016 Watts of solar irradiation continuously . • It is 1000 larger than our current power consumption from all sources • In atmosphere 6% irradiation is reflected and 16% is absorbed • When Radiations enter in earths atmosphere it under goes several interactions => Absorption and scattering • Scattering radiations is called diffuse radiation • Direct radiation or beam radiation • Reflected radiations is called albendo radiation • Sum of all the radiations is called global Radiations
- 4. Types of solarradiation on earth Direct
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- 6. Solar spectrum atearths Surface 2/16/2023 WCE, Sangli 6
- 7. AIR MASS • Lesssolar radiations will reach when they travel a longer distance through air mass ( Atmosphere) • Morning and Evening => solar radiations will travel a longer distance through air Mass • Radiation spectrum outside the earth surface is AM0 • During Noon radiation spectrum is AM1 • If sun rays making angle θ with vertical then AM= 1/cosθ •
- 8. Solar Radiation Spectrum 8 2/16/2023WCE, Sangli
- 9. Solar Irradiance underdifferent AM condition 9 2/16/2023 WCE, Sangli Air Mass Irradiation W/sq.m AM 0 => Extra Terrestrial 1376 AM 1 => Sun at over head position 1105 AM 1.5 => Sun at above 48 degree from overhead position 1000 AM 2 => Sun at about 60 deg from overhead position 894 894
- 10. Solar Radiation Measurement 10 2/16/2023WCE, Sangli • Various equipment's to measure solar radiations •Pyranometer => Measures global and diffused radiations •Pyreliometer => beam of direct solar radiations •Sunshine hour recorder => No. of sunshine hours
- 11. Measurement of solarradiation :Pyranometer 11 2/16/2023 WCE, Sangli • Construction: • Glass Domes • set of Thermo-couple • (Thermopile) • One end in black body • Voltage induced • Proportional • To light intensity • Global radiations
- 12. Pyranometer 12 2/16/2023 WCE, Sangli •thermo-couple • It is used to measure • Global direct and diffused • radiation
- 13. Pyranometer For measurementof diffused radiation 13 2/16/2023 WCE, Sangli • Shading Ring • Blocks the • Direct radiation • Then diffused • Radiations will • Fall on black plate
- 14. Pyrheliometer 14 2/16/2023 WCE, Sangli •It is used to measure direct radiations
- 15. Pyrheliometer 15 2/16/2023 WCE, Sangli •It is used to measure direct radiations • Two axis tracking mechanism
- 16. Sun shine recorder 16 2/16/2023WCE, Sangli • Construction • Glass Sphere • Light sensitive trace paper for recoding
- 17. Sun shine Recorder 17 2/16/2023WCE, Sangli