The document discusses solar energy and photovoltaic power conversion systems. It notes that the sun provides vastly more energy to Earth than is consumed and describes some key aspects of solar radiation. It also defines solar irradiance and discusses instruments used to measure direct and diffuse solar radiation, including pyranometers and pyrheliometers. Photovoltaic systems are introduced as arrangements that convert sunlight to electricity using solar panels.

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By: N.D.Solanki

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Photovoltaic Power Conversion systems
Solar Energy:
• Radiant energy emitted by the sun.
• The Sun daily provides about 10,000 times more energy to the Earth than
we consume.
• The earth receives 174 petawatts [1015 watts] of solar radiations from the
sun.
• The total energy absorbed by earth’s atmosphere, oceans, land mass is
38,50,000 exajoules [1018 joules] per year.
• The energy reaching earth’s atmosphere consists of about 8% UV
radiation, 46% visible light, 46% infrared radiations.

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Photovoltaic Power Conversion systems

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Photovoltaic Power Conversion systems
Solar constant:

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Photovoltaic Power Conversion systems
Radiation measurement:
• Solar irradiance is the power per unit area received from the Sun in the
form of electromagnetic radiation in the wavelength range of the
measuring instrument.
• Irradiance may be measured in space or at the Earth's
surface after atmospheric absorption and scattering. It is
measured perpendicular to the incoming sunlight

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Photovoltaic Power Conversion systems
1) The global or diffuse radiation : pyranometer
2) The beam radiation or direct radiation: Pyrheliometers
3) Sunshine recorders: this instrument used to measure hours of sunshine over a
day.

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Photovoltaic Power Conversion systems
Pyranometer:

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Photovoltaic Power Conversion systems

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Photovoltaic Power Conversion systems

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Photovoltaic Power Conversion systems
• A pyrheliometer is an instrument for measurement of direct beam solar
irradiance.
• Sunlight enters the instrument through a window and is directed onto
a thermopile which converts heat to an electrical signal that can be
recorded.
• The signal voltage is converted via a formula to measure watts per
square metre

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Photovoltaic Power Conversion systems

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Photovoltaic Power Conversion systems

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Photovoltaic Power Conversion systems
• Solar Energy :
• Solar Energy Solar energy can be used through two main
routes:
1. SOLAR THERMAL : For direct heating , cooking, drying and
power generation etc.
2. SOLAR PHOTOVOLTAIC : For direct electricity generation

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Photovoltaic Power Conversion systems
• Heating

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Photovoltaic Power Conversion systems
Distillation : The Device which converts saline water into pure water by
using solar energy is called solar still.
Diagram of most commonly used solar distillation is:

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Photovoltaic Power Conversion systems
• Dryer

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Photovoltaic Power Conversion systems
• Dryer

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Photovoltaic Power Conversion systems
Solar Energy:
• Radiant energy emitted by the sun.
• The Sun daily provides about 10,000 times more energy to the Earth than
we consume.
• The earth receives 174 petawatts [1015 watts] of solar radiations from the
sun.
• The total energy absorbed by earth’s atmosphere, oceans, land mass is
38,50,000 exajoules [1018 joules] per year.
• The energy reaching earth’s atmosphere consists of about 8% UV
radiation, 46% visible light, 46% infrared radiations.

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Photovoltaic Power Conversion systems

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Solar Photovoltaic(SPV) systems
• A photovoltaic system, also PV system or solar power system, is a power
system designed to supply usable solar power by means of photovoltaics.
• It consists of an arrangement of several components, including solar
panels to absorb and convert sunlight into electricity.

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Solar Photovoltaic(SPV) systems
Solar Cell :
• Solar cells are made from semiconductor materials.
• Converts sunlight into electricity according to the principle of
photovoltaic effect.
• Photovoltaic cells use p-n junction to generates electron-hole pairs which
in turn constitutes electric current.
• Light shining on the solar cell produces both a current and a voltage to
generate electric power.

22. Solar Cell Technology
Max Lab
Efficiency
Typical Cell
Thickness
Si Use Cost
Mono-crystalline Silicon (c-Si) 27.6% ~200µm High $$$
Poly-crystalline Silicon (p-Si) 20.4% ~200µm Moderate $$
Amorphous Silicon Thin Film (a-
Si)
12.5% <1µm Low $
 Why Silicon?
• Non-toxic
• Abundant
• Relatively cheap
• Mature infrastructure
from computer industry
c-Si Cell p-Si Cell a-Si Cell

23. The photoelectric effect was first noted
by a French physicist, Edmund
Bequerel, in 1839, who found that
certain materials would produce small
amounts of electric current when
exposed to light.
Albert Einstein explained the
underlying mechanism of light
instigated carrier excitation the photo
electric effect-in 1905

24. Photovoltaic Effect
Voltage is generated in a solar cell by a process known as the
‘photovoltaic effect’
Sunlight is composed of photons, or particles of solar energy that contain
various amounts of energy corresponding to the different wavelengths of
the solar spectrum.
The electrons present in the valence band absorb energy and, being
excited, jump to the conduction band and become free.
These highly excited electrons are accelerated
into a different material by a built-in
potential.
This generates an electromotive force, and
thus some of the light energy is converted into
electric energy.

25. Construction of Solar Cell

26. I-V curve and PV curve of solar cell

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I-V Curve of Solar Panel

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Efficiency of solar cell
1. The efficiency is the most commonly used parameter to compare the
performance of one solar cell to another.
2. Theoretical efficiency for PV is 86.8 % .
3. The maximum practical efficiency observed for solar power panel is 24.7
%.
4. But the general solar cell efficiency observed in daily applications is a
measly 13-14 %.
5. The solar panel power conversion efficiency can be given as :
6. Where Imax and vmax are the current and voltage for maximum power,
corresponding to solar intensity I (t) and Ac is Area of solar cell.

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Efficiency of Solar Panel
Major factors affecting solar power panel efficiency are :-
1) Dusting
2)Temperature rise effect
3)Poor sunlight absorption

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Effect of Dust On Performance Of Solar PV Panel
1. The heavy layer of dust accumulation on module array might cause
reduction in output power, so that can recovered by washing process
2. A major problem facing scientist is sand accumulation, hence numerous
researches proved that, more than 50% of solar module performance
reduction caused by unclean throughout period of one month
3. Performance of the PV module is proportional to dirt accumulation.
Actually as little of 10% shade on PV module array can result in of 50%
lost energy. Even though with an appropriate tilt angle installation still
sand particles accumulate on module surface.

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Effect of Dust On Performance Of Solar PV Panel
solar module covered by heavy
layer due to dust accumulation
before cleaning.
solar module after cleaning.

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Effect of Dust On Performance Of Solar PV Panel
To remove dust a wiper/slider mechanism is widely used in practice.
It will be programmed to wipe out the dust on the panel surface after a
particular period of time.
This duster will remove the dust particles hence preventing the fall in
efficiency of the panel and maintaining its original efficiency.
In addition to that clean solar panels are beautiful visually than unclean
panels.

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Effect of Dust On Performance Of Solar PV Panel

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Effect of temperature on solar power panel efficiency
1. Opposite to what we normally believe, solar panel efficiency is affected
negatively by temperature increase.
2. Heat can reduce output efficiency by 10-25%.
3. As temperature of the solar panel increases, output voltage decreases
exponentially
4. A field experiment in the UK revealed a drop of 1.1% of peak output for
every increase in degrees Celsius of a home photovoltaic solar panel,
once the panel reached 42 degree Celsius.
5. Solar power panels work best when maintained at a temperature of
around 25 degree Celsius.
:

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Effect of temperature on solar power panel efficiency
output P-V characteristics of the
PV module with different temperatures
Output I-V characteristics of the PV module
with different temperatures

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Solar Photovoltaic(SPV) systems

37. PV Modules
Assemblies of cells are used to make solar modules , also known as
solar panels and these panels are combined to form arrays.
For this , many cells are connected in series and/or parallel to obtain
the expected current and voltage levels and this set of cells is
mounted on an appropriate structure to create a photovoltaic module.

38. Applications of Solar Panels
•Solar Power Plant
•Household Applications
•Street Lights
•Satellites
•Solar Water Pumping
•Battery Charging
•Solar Automobiles