Oro551 res - unit 1 - physics of the sun

1. ORO551 - RENEWABLE ENERGY SOURCES
M.KARTHIKEYAN
ASSISTANT PROFESSOR
DEPARTMENT OF MECHANICAL ENGINEERING
AAA COLLEGE OF ENGINEERING & TECHNOLOGY, SIVAKASI
karthikeyan@aaacet.ac.in
8825676616M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI

2.  Position of the sun directly over head.
M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI
SUN AT ZENITH

3.  It is a vertical angle between the sun’s rays and a line
perpendicular to the horizontal plane through the point.
M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI
ZENITH ANGLE

4. 1. Role and potential of new and renewable source.
2. The solar energy option.
3. Environmental impact of solar power.
4. Physics of the sun.
5. The solar constant.
6. Extraterrestrial and terrestrial solar radiation.
7. Solar radiation on titled surface.
8. Instruments for measuring solar radiation and sun shine.
9. Solar radiation data.
UNIT I PRINCIPLES OF SOLAR RADIATION
M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI

5. COMPOSITION:
It contains,
 80% Hydrogen
 19% Helium
 1% More than 100 elements.
SOURCE OF SUN’S ENERGY:
Hydrogen to Helium Thermonuclear reaction.
M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI
PHYSICS OF THE SUN

6. M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI

7. INNER PARTS:
1. Core: where energy is produced (Thermonuclear fusion).
2. Radiative zone: energy is carried away from core as
electromagnetic radiation (photons) by the radiative diffusion
mechanism.
3. Convective zone: gas convects energy heat to surface.
M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI

8. OUTER PARTS
1. Photosphere: surface of Sun
2. Chromosphere: low density gases form “atmosphere”
3. Corona: outer part of atmosphere
M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI

9.  The Sun generates 9  1025 calories of energy every second.
 Diameter of the sun = 1.39x106 Km.
 Temperature at the outermost layer = 5485°C
 Temperature at the centre = 20x106 °C
 Rate of energy transmission from the sun = 3.8x1023 KW
[only 1.7x1014 KW is intercepted by the earth]
 Mean distance between the sun & earth = 150 million Km.
M.KARTHIKEYAN AP/MECH AAACET
SIVAKASI