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solar radiation measurement vivek singh

measurement of solar radiation

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solar radiation measurement vivek singh

  1. 1. 2/17/20162013BTECHEE014 1 PRESENTED BY:- VIVEK KUMAR SINGH 2013BTECHEE014 JK Lakshmipat University
  2. 2. SOLAR ENERGY TERMS • Solar Radiation-energy radiated by the sun. Or, Solar radiation is a term used to describe visible and near-visible (ultraviolet and near-infrared) radiation emitted from the sun. • Ultraviolet: 0.20 - 0.39 µm • Visible: 0.39 - 0.78 µm • Near-Infrared: 0.78 - 4.00 µm • Infrared: 4.00 - 100.00 µm • Solar irradiation-the radiated energy received on the earth surface. • Solar insolation-solar radiation received on a flat horizontal surface on earth 2/17/20162013BTECHEE014 2
  3. 3. Why we need solar radiation? It is important to measure solar radiation:- • Owing to increasing the number of solar heating and Colling application. • For accurate solar radiation data to predict performance. • To know the availability of the solar energy. 2/17/20162013BTECHEE014 3
  4. 4. DEVICES USED FOR MEASURING THE SOLAR ENERGY PYRANOMETER 2/17/20162013BTECHEE014 4 PYRHELIOMETER SUNSHINE RECORDER
  5. 5. 1.PYRANOMETER • It measure the total hemispherical solar radiation. • Solar constant-The average amount of solar radiation received by the Earth's atmosphere, per unit area, when the Earth is at its mean distance from the Sun. • The value of the solar constant is found experimentally to be 1368 W/m2. 2/17/20162013BTECHEE014 5
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  7. 7. 2/17/20162013BTECHEE014 7 CONSTRUCTION
  8. 8. • When it placed in sun rays then it receive the radiation, due to which the temperature of the surface(absorbing surface) start rising . • The rise in temperature of the absorbing surface is detected by thermopile. • Now the thermopile generate thermo emf proportional to radiation absorbed. • This thermo emf is calibrated in terms of received radiation 2/17/20162013BTECHEE014 8 working
  9. 9. placed in sun rays temperature of the surface(absorbing surface) start rising rise in temperature detected by thermopile thermopile generate thermo emf proportional to radiation absorbed This thermo emf is calibrated in terms of received radiation • Principle-working principle is that sensitive surface is exposed to total radiation. 2/17/2016 2013BTECHEE014 9 WORKING
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  11. 11. • Used to measure beam of direct radiation. • It collimate the radiation to determine the beam intensity as a function of incident angle. • Also known as normal incidence pyranometer. 2/17/20162013BTECHEE014 11 PYRHELIOMETER
  12. 12. Principle of working Sunlight enters the instrument through collimator tube and is directed onto a thermopile (sensing element) which converts heat to an electrical signal that can be recorded. 2/17/20162013BTECHEE014 12
  13. 13. CONSTRUCTION & WORKING 2/17/20162013BTECHEE014 13 • Uses a long collimator tube to collect beam radiation whose field of view is limited to a solid angle of 5.5° by appropriate diaphragms inside the tube. • Inner surface is blackened to absorb any radiation. • At the base of tube a wire wound thermopile having a sensitivity of approximately 8 micro volt/W/M^2 • Tube sealed with dry air to eliminate absorption of beam of radiation within the tube by water vapour.
  14. 14. • Measures the duration in hours of bright sunshine during the course of the day. 2/17/20162013BTECHEE014 14 Sunshine recorder
  15. 15. • Consist of a glass sphere installed in a section of “spherical metal bowl” having groves for holding a recorder card strip and the glass sphere. 2/17/20162013BTECHEE014 15 CONSTRUCTION
  16. 16. WORKING • Glass-sphere which act as a convex lens, focusses the sun’s rays to a point on the card strip. • Whenever there is bright sunshine the image formed is intense enough to burn a spot on the card strip. • The image moves along the strip due to the sun movement. • Thus a burnt space whose length is proportional to the duration of sunshine is obtained on the strip. 2/17/20162013BTECHEE014 16
  17. 17. Solar radiation data Solar radiation data includes following information:-  Whether they are instantaneous measurements or value integrated over some period of time. • Time period of the measurement. • Whether the measurement are of beam or of total radiation . When data are not available ‘maps’ can be used as a source of average radiation. 2/17/20162013BTECHEE014 17
  18. 18. Solar radiation data is collected on the basis of :- 1. Solar power calculation with reference to the movement of the sun 2. Hourly measurement of solar radiation at the location and calculation of :- o “daily average” at the location for a month (kj/m^2*day) o “Monthly average” at the location for various month (kj/m^2*year) 2/17/20162013BTECHEE014 18
  19. 19. Estimation of average solar radiation • Angstrom equation for average daily global radiation: 𝐻𝑔 𝐻𝑐 = a+{b (La/Lm)} Where, Hg=monthly average of the daily global radiation on a horizontal surface at the location(kj/m^2 day). Hc=monthly_ _ _ _ __ _ _ _ _ _ on the same horizontal surface at the same location but on clear sky day (kj/m^2 day). a,b=Constant determined from various cities in the world by measurements La= avg. length of solar day for a particular month calculated Lm=length of longest solar day in the month 2/17/20162013BTECHEE014 19
  20. 20. 2/17/20162013BTECHEE014 20 Modified angstrom’s equation
  21. 21. 2/17/20162013BTECHEE014 21
  22. 22.  Non conventional energy sources and utilization by Er. R K Rajput  Non conventional energy resources by B H Khan  www.globalspec.com  www.directindustry.com  http://www.campbellsci.com/solar-radiation 2/17/20162013BTECHEE014 22 BIBLIOGRAPHY
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