The document discusses the theory and components of solar cells. It provides information on:
1) The key components of solar cells including the p-n junction, semiconductor materials like silicon, and the photovoltaic effect which generates electricity from sunlight.
2) How solar cells work by using photon absorption to generate electron-hole pairs, which then travel across the p-n junction producing electricity.
3) The advantages of solar cells like being renewable, clean and requiring little maintenance, as well as disadvantages like high costs and inability to generate power at night.
The most common type of solar cells are Photovoltaic Cells (PV cells)
Converts sunlight directly into electricity
Cells are made of a semiconductor material (eg. silicon)
Light strikes the PV cell, and a certain portion is absorbed
The light energy (in the form of photons) knocks electrons loose, allowing them to flow freely, forming a current
Metal contacts on the top and bottom of PV cell draws off the current to use externally as power
The most common type of solar cells are Photovoltaic Cells (PV cells)
Converts sunlight directly into electricity
Cells are made of a semiconductor material (eg. silicon)
Light strikes the PV cell, and a certain portion is absorbed
The light energy (in the form of photons) knocks electrons loose, allowing them to flow freely, forming a current
Metal contacts on the top and bottom of PV cell draws off the current to use externally as power
Solar cell is the device that converts energy of light directly into electrical energy (electricity) by photovoltaic effect In general, a solar cell that includes both solar and non solar sources of light
(such as photons from incandescent bulbs) is termed a photovoltaic cell. Solar cell is also know as photovoltaic cell
Most familiar solar cells are based on the effect
of photovoltaic In this effect, light falling on semiconductor device of the two layer produces a potential difference or photo voltage between the layers The voltage thus produced can drive a current through an external circuit producing useful work
An Overview of Photovoltaic Systems or PV Systems. This PPT outlines what a solar systems is and what it is consisted of. From solar panels to charge controller to deep cycle batteries to the inverter.
This new minute lecture gives an introduction to photovoltaic (PV) systems for residential use, providing an answer to following questions:
* How does a PV system work?
* What can be expected from a PV system?
* What types of systems are available?
* How is technology expected to evolve?
introduction,advantage and disadvantage of solar energy,Generation of solar cell: 1st 2nd 3rd generation solar cell , I-V characteristics, working,application, efficiency data and advantage solar cell.
In presentation photovoltaic effect, solar cell material, types of solar cell, working principle, solar pv module, PV systems, Sizing of solar PV system etc are included.
Solar cell is the device that converts energy of light directly into electrical energy (electricity) by photovoltaic effect In general, a solar cell that includes both solar and non solar sources of light
(such as photons from incandescent bulbs) is termed a photovoltaic cell. Solar cell is also know as photovoltaic cell
Most familiar solar cells are based on the effect
of photovoltaic In this effect, light falling on semiconductor device of the two layer produces a potential difference or photo voltage between the layers The voltage thus produced can drive a current through an external circuit producing useful work
An Overview of Photovoltaic Systems or PV Systems. This PPT outlines what a solar systems is and what it is consisted of. From solar panels to charge controller to deep cycle batteries to the inverter.
This new minute lecture gives an introduction to photovoltaic (PV) systems for residential use, providing an answer to following questions:
* How does a PV system work?
* What can be expected from a PV system?
* What types of systems are available?
* How is technology expected to evolve?
introduction,advantage and disadvantage of solar energy,Generation of solar cell: 1st 2nd 3rd generation solar cell , I-V characteristics, working,application, efficiency data and advantage solar cell.
In presentation photovoltaic effect, solar cell material, types of solar cell, working principle, solar pv module, PV systems, Sizing of solar PV system etc are included.
All about the solar cell for the purpose of usage of solar cells and solar battery bank.if we want to take knowledge for a solar then we should need to know about the conversation of solar energy into electrical energy .
This is not an efficient conversation of energy because the conversation of solar energy in to electrical energy gives the output only 18% output
In this Presentation on solar cell is most effect for student of class 12
Contents:
Introduction to Solar Cells .
* The working principal of a solar cell .
* Types of solar cells.
* Working and construction.
* Benefit and disadvantages.
* application.
* Summary.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
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Honest Reviews of Tim Han LMA Course Program.pptxtimhan337
Personal development courses are widely available today, with each one promising life-changing outcomes. Tim Han’s Life Mastery Achievers (LMA) Course has drawn a lot of interest. In addition to offering my frank assessment of Success Insider’s LMA Course, this piece examines the course’s effects via a variety of Tim Han LMA course reviews and Success Insider comments.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
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June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
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Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
2. Theory of Solar Cell
Before we move towards solar energy collector or solar cell we
have to focus towards following points:
Solar constant
◦ Sun diameter = 1.39 x 106 km
◦ Earth diameter = 1.27 x 104 km
◦ Mean distance = 1.5 x 108 km
◦ The rate at which solar energy arrives at the top of the atmosphere is called solar
constant. This is the amount of energy received in unit time on a unit area
perpendicular to the sun’s direction at the mean distance of the earth from the
sun.
◦ NASA standard value for solar constant is 1353 watt/ m2
Solar Radiation
◦ Solar radiation that penetrate the earth’s atmosphere and reaches the surface
differs in both amount and character.
◦ Radiation reflected back by the clouds, then absorbed by the molecules in air.
3.
4. ◦ O2 and O3 absorb all UV radiation.
◦ Water vapors and CO2 absorb infra red radiation.
◦ Solar radiation which not absorbed and reaches to the ground is known as direct
radiation or beam radiation.
Solar radiation geometry
5. PH 0101 Unit-5 Lecture-2 5
Introduction
Photovoltaic effect
Electron-hole formation
A solar panel (or) solar array
Types of Solar cell
Principle, construction and working of
Solar cell
Advantage, disadvantage and
application
UNIT-1 LECTURE 2
6.
7.
8.
9.
10. PH 0101 Unit-5 Lecture-2 10
*Photo means light in Greek and Volt is the name of a
pioneer in the study of electricity .
Solar cell: Solar cell is a photovoltaic device that converts
the light energy into electrical energy based on
the principles of photovoltaic effect
Albert Einstein was awarded the 1921 Nobel Prize in physics
for his research on the photoelectric effect—a phenomenon
central to the generation of electricity through solar cells.
In the early stages, the solar cell was developed only with 4 to
6 % efficiency( because of inadequate materials and problems
in focusing the solar radiations). But, after 1989, the solar cells
with more than 50% efficiency was developed.
1. Introduction
11. PH 0101 Unit-5 Lecture-2 11
Three generations of solar cells
First Generation
First generation cells consist of large-area, high quality
and single junction devices.
First Generation technologies involve high energy and
labour inputs which prevent any significant progress in
reducing production costs.
12. PH 0101 Unit-5 Lecture-2 12
Second Generation
Second generation materials have been developed to
address energy requirements and production costs of
solar cells.
Alternative manufacturing techniques such as vapour
deposition and electroplating are advantageous as they
reduce high temperature processing significantly
13. PH 0101 Unit-5 Lecture-2 13
Materials for Solar cell
Solar cells are composed of various semiconducting materials
1. Crystalline silicon
2. Cadmium telluride
3. Copper indium diselenide
4. Gallium arsenide
5. Indium phosphide
6. Zinc sulphide
Note: Semiconductors are materials, which become
electrically conductive when supplied with light or heat, but
which operate as insulators at low temperatures
14. PH 0101 Unit-5 Lecture-2 14
• Over 95% of all the solar cells produced worldwide are
composed of the semiconductor material Silicon (Si). As the
second most abundant element in earth`s crust, silicon has
the advantage, of being available in sufficient quantities.
• To produce a solar cell, the semiconductor is contaminated
or "doped".
• "Doping" is the intentional introduction of chemical
elements into the semiconductor.
• By doing this, depending upon the type of dopant, one can
obtain a surplus of either positive charge carriers (called
p-conducting semiconductor layer) or negative charge
carriers (called n-conducting semiconductor layer).
15. PH 0101 Unit-5 Lecture-2 15
• If two differently contaminated semiconductor layers are
combined, then a so-called p-n-junction results on the
boundary of the layers.
• By doping trivalent element, we get p-type semiconductor.
(with excess amount of hole)
• By doping pentavalent element, we get n-type
semiconductor ( with excess amount of electron)
n-type semiconductor
p- type semiconductor
p-n junction layer
16. PH 0101 Unit-5 Lecture-2 16
2. Photovoltaic effect
Definition:
The generation
of voltage across the
PN junction in a
semiconductor due
to the absorption of
light radiation is
called photovoltaic
effect. The Devices
based on this effect
is called photovoltaic
device.
Light
energy
n-type semiconductor
p- type semiconductor
Electrical
Power
p-n junction
17. PH 0101 Unit-5 Lecture-2 17
3. electron-hole formation
• Photovoltaic energy conversion relies on the number
of photons strikes on the earth. (photon is a flux of
light particles)
• On a clear day, about 4.4 x 1017 photons strike a square
centimeter of the Earth's surface every second.
• Only some of these photons - those with energy in
excess of the band gap - can be converted into
electricity by the solar cell.
• When such photon enters the semiconductor, it may
be absorbed and promote an electron from the
valence band to the conduction band.
18. PH 0101 Unit-5 Lecture-2 18
• Therefore, a vacant is created in the valence band and it is
called hole.
• Now, the electron in the conduction band and hole in
valence band combine together and forms electron-hole pairs.
hole
Valence band
Conduction band
electron
Photons
19. PH 0101 Unit-5 Lecture-2 19
4. A solar panel (or) Solar array
Single solar cell
• The single solar cell constitute the n-typpe layer
sandwiched with p-type layer.
• The most commonly known solar cell is configured as a
large-area p-n junction made from silicon wafer.
• A single cell can produce only very tiny amounts of electricity
• It can be used only to light up a small light bulb or power a
calculator.
• Single photovoltaic cells are used in many small electronic
appliances such as watches and calculators
20. PH 0101 Unit-5 Lecture-2 20
N-type
P-type
Single Solar cell
21. PH 0101 Unit-5 Lecture-2 21
Solar panel (or) solar array (or) Solar module
The solar panel (or) solar array is the interconnection of
number of solar module to get efficient power.
• A solar module consists of number of interconnected
solar cells.
• These interconnected cells embedded between two
glass plate to protect from the bad whether.
• Since absorption area of module is high, more energy
can be produced.
23. PH 0101 Unit-5 Lecture-2 23
Based on the types of crystal used, soar cells can be classified as,
1. Monocrystalline silicon cells
2. Polycrystalline silicon cells
3. Amorphous silicon cells
1. The Monocrystalline silicon cell is produced from
pure silicon (single crystal). Since the Monocrystalline
silicon is pure and defect free, the efficiency of cell will be
higher.
2. In polycrystalline solar cell, liquid silicon is used as raw material
and polycrystalline silicon was obtained followed by solidification
process. The materials contain various crystalline sizes. Hence,
the efficiency of this type of cell is less than Monocrystalline cell.
5. Types of Solar cell
24. PH 0101 Unit-5 Lecture-2 24
3. Amorphous silicon was obtained by depositing silicon
film on the substrate like glass plate.
•The layer thickness amounts to less than 1µm – the
thickness of a human hair for comparison is 50-100 µm.
•The efficiency of amorphous cells is much lower than that
of the other two cell types.
• As a result, they are used mainly in low power
equipment, such as watches and pocket calculators,
or as facade elements.
25. PH 0101 Unit-5 Lecture-2 25
Comparison of Types of solar cell
Material Efficiency (%)
Monocrystalline silicon 14-17
Polycrystalline silicon 13-15
Amorphous silicon 5-7
26. PH 0101 Unit-5 Lecture-2 26
6. Principle, construction and working of Solar cell
Principle: The solar cells are based on the principles
of photovoltaic effect.The photovoltaic effect is the
photogeneration of charge carriers in a light absorbing
materials as a result of absorption of light radiation.
Construction
• Solar cell (crystalline Silicon) consists of a n-type
semiconductor (emitter) layer and p-type semiconductor
layer (base). The two layers are sandwiched and hence
there is formation of p-n junction.
• The surface is coated with anti-refection coating to avoid the
loss of incident light energy due to reflection.
28. Material for solar coating
silicon nitride, silica (SiO2), Titania
and zinc oxide.
There several techniques to fabricate
them , which mainly depend on the
type of application.
PH 0101 Unit-5 Lecture-2 28
30. PH 0101 Unit-5 Lecture-2 30
• A proper metal contacts are made on the n-type and p-
type side of the semiconductor for electrical connection
Working:
• When a solar panel exposed to sunlight , the light energies
are absorbed by a semiconduction materials.
• Due to this absorded enrgy, the electrons are libereted
and produce the external DC current.
• The DC current is converted into 240-volt AC current using
an inverter for different applications.
31. PH 0101 Unit-5 Lecture-2 31
Mechanism:
• First, the sunlight is absorbed by a solar cell in a solar
panel.
• The absorbed light causes electrons in the material to
increase in energy. At the same time making them free to
move around in the material.
• However, the electrons remain at this higher energy for
only a short time before returning to their original lower
energy position.
• Therefore, to collect the carriers before they lose the
energy gained from the light, a PN junction is typically
used.
32. PH 0101 Unit-5 Lecture-2 32
• A PN junction consists of two different regions of a
semiconductor material (usually silicon), with one side
called the p type region and the other the n-type region.
• During the incident of light energy, in p-type material,
electrons can gain energy and move into the n-type region.
• Then they can no longer go back to their original low
energy position and remain at a higher energy.
• The process of moving a light- generated carrier from
p-type region to n-type region is called collection.
• These collections of carriers (electrons) can be either
extracted from the device to give a current, or it can remain in
the device and gives rise to a voltage.
33. PH 0101 Unit-5 Lecture-2 33
• The electrons that leave the solar cell as current give
up their energy to whatever is connected to the solar
cell, and then re-enter the solar cell. Once back in the
solar cell, the process begins again:
34. PH 0101 Unit-5 Lecture-2 34
The mechanism of electricity production- Different stages
Conduction band High density
Valence band Low density
E
The above diagram shows the formation of p-n junction in a solar
cell. The valence band is a low-density band and conduction
band is high-density band.
35. PH 0101 Unit-5 Lecture-2 35
Stage-1
Therefore, the hole
(vacancy position left
by the electron in the
valence band) is
generates. Hence, there
is a formation of
electron-hole pair on
the sides of p-n
junction.
When light falls on the semiconductor surface, the electron
from valence band promoted to conduction band.
Conduction band High density
Valence band Low density
E
36. PH 0101 Unit-5 Lecture-2 36
Stage-2
In the stage 2, the electron and holes are diffuse across the
p-n junction and there is a formation of electron-hole pair.
Conduction band High density
Valence band Low density
E
junction
37. PH 0101 Unit-5 Lecture-2 37
Stage-3
In the stage 3, As electron continuous to diffuse, the negative
charge build on emitter side and positive charge build on the
base side.
Conduction band High density
Valence band Low density
E
junction
38. PH 0101 Unit-5 Lecture-2 38
Stage-4
When the PN junction is connected with external circuit, the
current flows.
Conduction band High density
Valence band Low density
E
junction
Power
39. PH 0101 Unit-5 Lecture-2 39
7. Advantage, disadvantage and application of Solar cell
Advantage
1. It is clean and non-polluting
2. It is a renewable energy
3. Solar cells do not produce noise and they are totally
silent.
4. They require very little maintenance
5. They are long lasting sources of energy which can be
used almost anywhere
6. They have long life time
7. There are no fuel costs or fuel supply problems
40. PH 0101 Unit-5 Lecture-2 40
Disadvantage
1. Soar power can be obtained in night time
2. Soar cells (or) solar panels are very expensive
3. Energy has not be stored in batteries
4. Air pollution and whether can affect the production
of electricity
5. They need large are of land to produce more
efficient power supply
41. PH 0101 Unit-5 Lecture-2 41
Applications
1.Soar pumps are used for water supply.
1.Domestic power supply for appliances include
refrigeration, washing machine, television and lighting
1.Ocean navigation aids: Number of lighthouses and
most buoys are powered by solar cells
1.Telecommunication systems: radio transceivers on
mountain tops, or telephone boxes in the country can
often be solar powered
1.Electric power generation in space: To providing
electrical power to satellites in an orbit around the Earth
46. Solar Energy collector
Flat plate collectors
When temp. below about 90 ◦C are adequate and for water heating.
They are made in rectangular panels from about 1.7 to 2.9 m2 in
area.
Flat plate can collect and absorb both direct and diffuse solar
radiation.
They are effective even on cloudy days when there is no direct
radiation.
Flat plate solar collectors may be divided into two main
classification based on the type of heat transfer fluid used.
◦ Liquid heating collectors
◦ Solar air heater or air collectors
The difference between the two types is the design of the
passages for the heat for the transfer fluid.
47. Major components
A transparent cover which may be one or more sheets of glass or
radiation transmitting plastic film or sheet.
Tubes, fins, or passages or channels are integral with the collector
absorber plate or connected to it, which carry the water, air or other
fluid.
The absorber plate, normally metallic or with a black, surface,
although a wide variety of other materials can be used with air
heaters.
Insulation, which should be provided at the back and sides to
minimize the heat losses. Standard insulating materials such as fiber
glass or styro foam are used for this purpose.
the casing or container which enclose the other components and
protects them from the weather.
48. Typical liquid collector
There are many flat plate collector design, but most are based on
principle as shown in diagram:
It is the plate and tube type collector.
It basically consists of a flat surface with high absorptive for solar
radiation, called the absorbing surface.
A metal plate usually of copper, steel or aluminum materials with
tubing of copper in thermal contact with the plate, are the most
commonly used materials.
49.
50.
51. Fluid (water and ehtylene
glycol)
The absorber plate is usually made from a metal sheet 1 to 2 mm in
thickness, while the tube range in diameter 1 to 1.5 cm.
they are soldered to the bottom or top of the absorber plate with the
pitch ranging from 5 to 15 cm.
Heat is transferred from the absorber plate to a point of use by
circulation of fluid (usually water) across the solar heated surface.
Thermal insulation of 5 to 10 cm thickness is usually placed behind
the absorber plate to prevent the heat losses from the rear surface.
Insulation materials is generally mineral wool or glass wool or fibre
wool.
The front cover is generally glass and opaque to the infra red re-
radiation from the absorber. (act like convection shield).
Thickness of glass i.e. 3 to 4 mm.
Typical dimensions of collector = 2m x 1m x 15 cm
52. Concentrating Collector
They are also known as focusing collector.
The concentrating collector are used for medium (100-300◦C),
application such as steam production for generation of electricity.
The high temperature is achieved at absorber because of reflecting
arrangement provided for concentrating the radiation required
location using mirror and lenses.
These collector are best suited at place having more numbers of
clean days in a year.
Concentrating collector employ systems in the form of reflectors to
concentrate the energy of direct solar radiation on the absorbing
surface.
Application demanding temperature of 250◦F or higher usually
requires a concentrating collector.
53.
54. They are also called as focusing type collectors.
The surface of a concentrating collector must be highly reflective,
enabling concentration of the sun’s rays on the heat absorption
device.
Such collectors normally use optical system in the form of
reflectors.
In these collectors, the solar radiation falling on a relatively large
area is concentrated on to receiver or absorber of significantly lesser
area.
as a result of the energy concentration, fluids can be heated to
temperatures up to 500◦C or more.
The heat transfer fluid can be a liquid or gas.
55. Focusing type collectors concentrate only direct radiation coming
from a specific direction.
Therefore, concentrating collector is usually a tracing collector in
order to keep the sun’s rays focused on a small surface.
Concentrating collectors that accurately track the suns position are
more efficient that the non tracking one.
Other type of concentrating, tracking collectors use movable
mirrors that can concentrate the solar energy on a small surface
that remains fixed.
The angle of the individual mirrors are such that they reflect solar
radiation from a specific direction on to the same focal point.
These fully tracking mirrors are usually computer controlled to
concentrate the maximum amount of solar energy.
Application are mainly for steam generation used to produce
electric power.
56. Material for concentrating
collector
The reflector should have high reflectivity. Therefore mirror glass
may be used.
Glass is the most durable with low iron content and are used as
transmitting material.
Now a days plastic are also in use. Acrylic is found to be good
material for fresnel lenses.
Poly methyl methacrylate
is generally used.
Aluminum and silver are
very good reflecting
surfaces.
57. Glass and transparent plastic films are generally used as cover
material for receivers.
Coating are required to have strong solar absorptivity, weather
resistance, stability at high temperature. Black paint is good.
It can be electroplated on steel, copper, aluminum etc.
58. Advantages and disadvantages
of concentrating collector
Advantage
These collectors are used for high temperature application.
Thermal losses are less.
The efficiency increases at high temp.
The size of the absorber can be reduced that gives high
concentration ratio.
Disadvantages
Non uniform flux on absorber.
It collects only beam radiation because diffuse radiation
components can not be reflected, hence these are lost.
Need costly tracking device.
High initial cost.
Need maintenance to retain the quality of reflecting surface against
dirt and oxidation.
59. Performance of concentrating
collectors
The useful heat output Qc of a concentrating collector is given by:
The optical efficiency of a concentrating collector is defined as the
ratio of the solar radiation absorbed by the absorber to the beam
radiation on the concentrator and is given by :
60.
61. Solar Cell power plant
As we discussed semiconductor materials such as silicon are used in
photovoltaic solar cell.
In the cell incoming photons separate positive and negative charge
carriers.
This produces and electrical voltage and electric current and can
drive a load.
The solar cell can be connected in series and parallel and
incorporated in a module.
Several modules may be interconnected to comprise a solar array,
but a large land area is required.
In solar cell power plant we generally convert solar energy into
electrical energy.
62.
63. There are two types of solar power plants namely:
◦ Grid independent solar power plant
◦ Grid connected solar power plant
Grid independent solar power plant
Grid independent solar power plant are also known as stand alone
PV power plant or Autonomous solar power plant for supplying
the current and having no connection with grid.
These power plants are used for local network such as solar water
pump, telecommunications, home power supply in rural areas.
The main components of Autonomous solar power plant are as
follows:
◦ Photovoltaic array
◦ Storage battery
◦ Power conditioner
64. (a) Photovoltaic array
It consists of the required number of modules interconnected in
series and parallel to give desired system voltage and current.
(b) Storage battery
The battery supplies energy to the load during periods of little or no
solar irradiance and solar energy from the array during periods of
high irradiance.
This enables the system to meet momentary peak power demands
and to maintain stable voltage to load.
(c) Power conditioner
Because the voltage output of the photovoltaic array varies with
insolation and temperature.
65. systems with battery storage require voltage or shunt regulator to
prevent excessive overcharging of the battery.
Further controls are used to prevent discharge or to ensure that the
array is operating at its maximum power point.
Figure shows the combined solar/wind/diesel power plant
67. Grid connected solar power plant
In block diagram photovoltaic array produces DC power and this
must be converted into AC power for local use and feeding into
grid.
An inverter converts DC voltage to AC and feeds the solar power to
grid or supply to consumer.
In case of low power availability from photovoltaic generation, the
local load can be fed from the grid.
68. s
Photovoltaic arrays supplies the current only when sunlight falling
on it, the magnitude of direct current depends upon the intensity of
solar radiation.
In grid connected system the power is fed into the grid during day
time and taking power from grid during night.
Grid connected system require additional components to regulate
voltage, frequency and waveform to meet the requirement of
feeding the power into the grid.
69. Solar cell materials
The solar cell are made of various materials.
Silicon is the most commonly used material for the solar cell.
The electrical properties of silicon depends on the type and amount
of dopants.
Phosphorous and Boron are most widely used donor and acceptor
dopant in silicon.
The choice of the material depend upon the energy band gap,
efficiency and cost.
There are four important types of material which is used in solar
cells:
◦ Single crystal silicon
◦ Poly crystalline and Amorphous silicon
◦ Cadmium sulphide cadmium telluride
◦ Copper indium diselenide