This document provides an overview of renewable energy sources as taught by Prof. Madhuri K. Pawar. It discusses various renewable sources including solar energy, wind energy, bioenergy, geothermal energy and ocean energy. For solar energy specifically, it describes the physics of the sun including its layers of core, radiative zone, convection zone, photosphere, chromosphere and corona. It also discusses the solar constant, terrestrial radiation and extra-terrestrial radiation. The document aims to educate students on different renewable sources and the fundamentals of solar energy as the most abundant renewable resource.

1. Renewable Energy Sources
PROF. MADHURI K. PAWAR
A S S I S TA N T P R O F E S S O R , D E PA R T M E N T O F E L E C T R I C A L E N G I N E E R I N G ,
S V E R I ’ S C O L L E G E O F E N G I N E E R I N G ,
PA N D H A R P U R .
C O N TA C T: + 9 1 9 6 0 4 3 4 9 3 8 8
E M A I L : - M K PAWA R @ C O D . S V E R I . A C . I N
1.Solar Radiation & its Measurement
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2. Welcome to All
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3. Syllabus
1. Solar Radiation and its Measurement
2. Solar Energy Collection
3. Solar Energy Storage and Applications
Different methods, Sensible, latent heat and stratified
storage, solar ponds, Solar Applications-solar heating/cooling
technique, solar distillation and drying, photovoltaic energy
conversion
Flat plate and concentrating collectors, classification of
concentrating collectors, orientation and thermal analysis,
advanced collector
Role and potential of new and renewable source, the solar
energy option, physics of the sun, the solar constant,
terrestrial and extra-terrestrial solar radiation, solar radiation
on tilted surface, instruments for measuring solar radiation
and sun shine, solar radiation data.
Section-I Section-II
Principles of Bio-Conversion, Anaerobic/aerobic digestion, types
of Bio-gas digesters, gas yield, combustion characteristics of bio-
gas, utilization for cooking, I.C. Engine operation and economic
aspects
5. Bio-Mass
6. Geothermal Energy
Resources, types of wells, methods of harnessing the energy,
potential in India.
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4. Wind Energy
Sources and potentials, site selection considerations, Basic
components of a WECS, classification of WEC systems,
advantages and disadvantages of WECS, horizontal and
vertical axis windmills, performance characteristics of Wind-
machines, Bet’z criteria
7. Ocean Energy
OTEC, Principles utilization, setting of OTEC plants,
thermodynamic cycles, Tidal and wave Energy: Potential and
conversion techniques, mini-hydel power plants, and their
economics
8. Direct Energy Conversion
Need for DEC, Carnot cycle, limitations, principles of DEC

4. What are renewables -
• These are resources found in nature that are self regenerating.
• Renewable energy is the energy generated from natural resources like solar, wind, geo,
hydro, bio & tidal.
• These sources are normally used to produce clean (or green) energy. This production
does not lead to climate change & does not involve emission of pollutants.
•These are secondary energy sources.
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5. Comparison between energy sources-
RENEWABLE ENERGY
1. It can be used again & again throughout its
life.
2. It is sustainable.
3. The rate of renewal is greater than the rate of
consumption.
4. These resources are present in unlimited
quantity.
5. Pollution free.
6. Sunlight, wind are examples of renewable
resources.
NON - RENEWABLE ENERGY
1. It is limited which can be depleted one day.
2. It is exhaustible.
3. The rate of renewal is lower than the rate
of consumption.
4. These resources are present in limited
quantity.
5. Not pollution free.
6. Coal, petroleum, natural gases, batteries.
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6. Need for renewable sources-
1) Limited primary reserves.
2) Pollution free
3) Clean
4) Eco friendly
5) Cheap in cost
6) Abundantly available
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7. Solar Energy -
• The energy from the sun in the form of radiation is called solar energy.
•The sun is a source of enormous energy.
•India receives solar energy equivalent to over 5000 trillion Kwh/year.
•Collecting solar energy in the form of heat & using the heat as such is the
principle of solar energy devices.
•Example- solar cooker, solar heater, geyser etc.
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8. The solar energy option-
1. It’s a free source of energy.
2. It Can Make Use of the Underutilized Land
3. It Can Cause Less Electricity Loss
4. It Can Make Your Home Go Off-the-Grid
5. It’s Good for the Environment
6. It Helps Improve Your Grid Security
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9. Sun as a source of energy -
•The radiant energy emitted by the sun is called solar energy.
•Solar energy has the greatest potential of all the sources of renewable energy.
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10. Physics of sun-
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11. Physics of sun-
•This graphic shows a model of the layers of the Sun.
•For the inner layers, the mileage is from the sun's core; for the outer layers, the
mileage is from the sun's surface.
•The inner layers are the Core, Radiative Zone and Convection Zone.
•The outer layers are the Photosphere, the Chromosphere and the Corona.
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13. 1.Core-
• The Sun's core is the central region where nuclear reactions consume hydrogen to form helium.
•These reactions release the energy that ultimately leaves the surface as visible light.
•The temperature at the very center of the Sun is about 15,000,000° C.
•And the density is about 150 g/cm³.
•Thermonuclear fusion is the process that occurs when two atoms combine to make a larger
atom, creating a whole lot of energy.
•The core is the sun’s hardest layer.
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14. 2.Radiative zone -
•The radiative zone is a thick layer of highly ionized, very dense gases which are under constant
bombardment by the gamma rays from the core.
•The nuclear energy generated in the sun’s core travels to the radiative zone in the form of
electromagnetic radiation better known as light.
•The Sun's radiative zone is the section of the solar interior between the innermost core and the
outer convective zone.
•Density slightly decreases but it’s still tremendous.
•The radiative zone is 186,965 miles across
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15. 3.Convection zone-
•The convection zone is the outer-most layer of the solar interior.
•It extends from a depth of about 200,000 km right up to the visible surface.
•At the base of the convection zone the temperature is about 2,000,000° C.
•Now density finally becomes low enough for light travelling out of core to transform into heat.
•The rising material will dissipate its heat (energy) into the surrounding environment, become
more dense (cooler), and will sink to start the process over.
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17. 4.Photosphere -
•The photosphere is a sun's outer shell from which light is radiated.
•It is very very thin layer about a 100-400km thick.(physical limit of the sun)
•Its density is 0.01% of earths atmosphere density.
•The Sun is composed primarily of the chemical elements hydrogen and helium; they account for
74.9% and 23.8% of the mass of the Sun in the photosphere.
•Temperature is about 6000 degrees kelvin.
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18. 5.Chromosphere-
•The chromosphere is above the photosphere, the visible "surface" of the Sun.
•It lies below the solar corona, the Sun's upper atmosphere.
•The plasma (electrically charged gas) in the chromosphere has a very low density.
• The temperature decreases with height - from roughly 6,000° C .
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19. 6.Corona-
•The Sun’s corona is the outermost part of the Sun’s atmosphere.
•The corona is usually hidden by the bright light of the Sun's surface.
•The corona is about 10 million times less dense than the Sun’s surface. This low density makes
the corona much less bright than the surface of the Sun.
•The corona extends far out into space. From it comes the solar wind that travels through our
solar system. The corona's temperature causes its particles to move at very high speeds. These
speeds are so high that the particles can escape the Sun's gravity.
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20. 6.Corona-
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21. Solar constant-
•The sun is a large sphere of very hot gases, the heat being generated by various kinds of fusion
reactions.
•Its diameter is 1.39*10^6 km while that of the earth is 1.27*10^8 km.
•The mean distance between sun & earth surface is 1.50* 1068 km .
•Although the sun is large, it subtends an angle of 32 minutes at the earth’s surface & this is
because it is also at a very large distance.
•Thus the beam radiation received from the sun on the earth is almost parallel.
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22. Solar constant-
•The rate at which solar energy arrives at the top of the atmosphere is called the solar constant
Isc.
•The amount of energy received in unit time on a unit area perpendicular to sun’s direction at
the mean distance of the earth from the sun.
•Because of the sun distance & activity vary throughout the year, the rate of arrival of solar
radiation varies accordingly.
•The National Aeronautics and Space Administration’s (NASA) standard value for the solar
constant is 1.353Kw/m^2.
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23. Solar constant-
n – day of year
I – Intensity of solar radiation that reaches the earth.
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24. Terrestrial radiation-
•The insolation received by the earth is in short waves forms & heats up its surface.
•The earth after being heated itself becomes a radiating body & it radiates energy to the
atmosphere in long waveform.
•This energy heats up the atmosphere from below.
•The long wave radiation is absorbed by the atmospheric gases particularly by carbon dioxide ,
water vapor & other greenhouse gases, so the atmosphere is indirectly heated by the earth’s
radiation.
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25. Terrestrial radiation-
•The atmosphere in turn radiates & transmits heat to the space.
•The amount of heat received from the sun is returned to space thereby maintaining constant
temperature at the earth’s surface & in the atmosphere.
•The solar radiation that reaches the earth surface after passing through earth’s atmosphere is
known as terrestrial radiation.
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26. Extra terrestrial radiation-
•Solar radiation incident outside the earth's atmosphere is called extraterrestrial radiation.
• On average the extraterrestrial irradiance is 1361 Watts/meter2 (W/m2).
•This value varies by ±3% as the earth orbits the sun.
•The extraterrestrial radiation is
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Io= 1361 * (Rav / R)2 W/m2
Rav is the mean sun-earth distance
R is the actual sun-earth distance depending on the day
of the year.

27. If Any Queries, Let me Know!!!!!
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