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INDEX LIST OF FIGURE I
SOLAR ENERGY 11.1 INTRODUCTION 2
1.2 APPLICATION OF SOLAR
ENERGY7
1.2.1 ARCHITECTURE &URBAN PLANNING
81.2.2 AGRICULTURE &
HORTICULTURE9
! 1.2.3 SOLAR LIGHTING 10' 1.2.4 WATER HEATING 11
1.2.5 SOLAR COOKER 121.3 ENERGY STORAGE
METHOD13
1 1.4 DEVELOPMENT 14"* SOLAR TRACKER 15
2.1 HISTORY 162.2 TYPES QF SOLAR TRACKER 172.2.1 HORIZONTAL AXLE 182.2.2 VERTICAL AXLE 192.2.3 ALTITUDE-AZIMUTH 202.2.4 TWO-AXIS MOUNT 21
2.2.5 MULTI-MIRROR REFLECTIVE
UNIT22
2.3 DRIVE TYPES 232.3.1 ACTIVE TRACKER 232.3.2 PASSIVE TRACKER 242.3.3 CHRONOLOGICAL TRACKER 252.3.4 THIN-FILM SOLAR TRACKER 26
& SOLAR CELL
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27
1. INTRODUCTION 28
2. TYPES OF SOLAR CELL 29
1. HIGH-EFFICIENCY CELLS 29
2. MULTIPLE-JUNCTION SOLAR CELLS 31
3. THIN-FILM SOLAR CELLS 32
4. CRYSTALLINE SILICON 33
1. APPLICATION 34
2. SOLAR CELL EFFICIENCY FACTOR 35
3. MATERIAL USED FOR SOLAR CELL 40
DESIGN AND DEVELOPMENT
OF SOLAR TRACKER 42
1. METHOD OF POWER GENERATION 43
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2. SELECTION OF MATERIAL 44
3. DETAIL OF EACH COMPONENT 45
4. ASSEMBLY OF SOLAR TRACKER 52
5. WORKING OF SOLAR TRACKER 53
6. COST OF SOLAR TRACKER 54
7.
1.
FUTURE ASCPECT 55
1. FUTURE ASCPECT 56
2. CONCLUSION 57
3. REFERANCES 58
4.
LIST OF FIGURES
Fig No. Title1.1 Use of different energy in the word1.2 Use of solar energy in the world1.3 Architecture Building1.4 Farm house1.5 Solar lighting1.6 Water heating1.7 Solar cooker2.1 Horizontal Axle2.2 Vertical Axle2.3 Two Axis Mount2.4 Multi mirror reflective unit2.5 Thin-film solar tracker3.1 Types of solar cells & its efficiency4.1 Assembly of base stand4.2 Gear box
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4.3 Solar Plate4.4 Battery Assembly4.5 Assembly of solar trackerPage No.
SOLAR ENERGY
CONTENTS:
1. INTRODUCTION2. APPLICATION OF SOLAR ENERGY
3.1.
1. ARCHITECTURE & URBAN PLANNING
2. AGRICULTURE & HORTICULTURE
3. SOLAR LIGHTING
1. WATER HEATING2. SOLAR COOKER3.
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1.
[
~-
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1. ENERGY STORAGE METHOD2. DEVELOPMENT3.1.1 INTRODUCTION
In today's climate of growing energy needs and increasing environmental concern,
alternatives to the use of non-renewable and polluting fossil fuels have to be
investigated. One such alternative is solar energy.
Solar energy is quite simply the energy produced directly by the sun and collected
elsewhere, normally the Earth.
Solar energy is the radiant light and heat from the Sun that has been harnessed by
humans since ancient times using a range of ever-evolving technologies. Solar
radiation along with secondary solar resources such as wind and wave power,
hydroelectricity and biomass account for most of the available renewable energy on
Earth. Only a minuscule fraction of the available solar energy is used.
Solar power provides electrical generation by means of heat engines or photovoltaic.
Once converted its uses are only limited by human ingenuity. A partial list of solar
applications includes space heating and cooling through solar architecture, potable
water via distillation and disinfection, daylighting, hot water, thermal energy for
cooking, and high temperature process heat for industrial purposes. Solar
technologies are broadly characterized as either passive solar or active solar
depending on the way they capture, convert and distribute sunlight. Active solar
techniques include the use of photovoltaic panels, solar thermal collectors, with
electrical or mechanical equipment, to convert sunlight into useful outputs. Passive
solar techniques include orienting a building to the Sun, selecting materials with
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favorable thermal mass or light dispersing properties, and designing spaces that
naturally circulate air.
The Earth receives 174 peta watts (PW) of incoming solar radiation (insulation) at
the upper atmosphere. Approximately 30% is reflected back to space while the rest
is absorbed by clouds, oceans and land masses. The spectrum of solar light at the
Earth's surface is mostly spread across the visible and near-infrared ranges with a
small part in the near-ultraviolet.
Earth's land surface, oceans and atmosphere absorb solar radiation, and thisraises their temperature. Warm air containing evaporated water from the oceans
rises, causing atmospheric circulation or convection. When the air reaches a high
altitude, where the temperature is low, water vapor condenses into clouds, which
rain onto the Earth's surface, completing the water cycle. The latent heat of water
condensation amplifies convection, producing atmospheric phenomena such as
wind, cyclones and anti-cyclones. Sunlight absorbed by the oceans and land
masses keeps the surface at an average temperature of 14 C. By photosynthesis
green plants convert solar energy into chemical energy, which produces food, wood
and the biomass from which fossil fuels are derived.
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~ .s ~
> ' I ) > )
) )
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i
Coal 2 5% Gas 2 3%
I
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Biomass 4% Hydrouclear>A>
fN
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ir r
olar heat 0.5% Wind 0.3%
*
Geothermal
0.2%
B
io
f
u
e
l
s
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0
.
2
%
S
o
l
a
r
p
h
o
t
o
v
o
l
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t
a
i
c
0
.
0
4
%
1.1 Use of Different Energy in
the World
~ 4
As we seen from the above graph solar energy is most wildly use as a non-
conversional energy in the world. Renewable energy sources are even larger than
the traditional fossil fuels and in theory can easily supply the world's energy needs.
89 PW of solar power falls on the planet's surface. While it is not possible to capture
all, or even most, of this energy, capturing less than 0.02% would be enough to meet
the current energy needs. Barriers to further solar generation include the high price
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of making solar cells and reliance on weather patterns to generate electricity. Also,
solar generation does not produce electricity at night, which is a particular problem
in high northern and southern latitude countries; energy demand is highest in
winter, while availability of solar energy is lowest. This could be overcome by
buying power from countries closer to the equator during winter months. Globally,
solar generation is the fastest growing source of energy, seeing an annual average
growth of 35% over the past few years. Japan, Europe, China, U.S. and India are
the major growing investors in solar energy. Advances in technology and
economies of scale, along with demand for solutions to global warming, have led
photovoltaic to become the most likely candidate to replace nuclear and fossil
fuels.
~5~
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7.2 TW
32 TW
86,000 TW
Hydro Geothermal
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870 TW
15 TW
Glob
al Solar Wind
Consumption 1.2 Use of Solar
Energy in the World
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1.2 APPLICATIONS OF SOLAR ENERGY
ARCHITECTURE AND URBAN PLANNING
AGRICULTURE AND HORTICULTURE
SOLAR LIGHTING
SOLAR THERMAL
WATER HEATING
HEATING, COOLING AND VENTILATION
WATER TREATMENT
COOKING
PROCESS HEAT
ELECTRICAL GENERATION
EXPERIMENTAL SOLAR POWER
SOLAR CHEMICAL
SOLAR VEHICLES
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7
1.2.1 ARCHITETURE AND URBAN PLANNING
Darmstadt University of Technology in
Germany won the 2007 Solar Decathlon in
Washington, D.C. with this passive house
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designed specifically for the humid and hot
subtropical climate. Sunlight has influenced
1.3 Architecture Building building design since the
beginning of architectural history. Advanced solar architecture and urban planning
methods were first employed by the Greeks and Chinese, who oriented their
buildings toward the south to provide light and warmth.
The common features of passive solar architecture are orientation relative to the
Sun, compact proportion (a low surface area to volume ratio), selective shading
(overhangs) and thermal mass. When these features are tailored to the local climate
and environment they can produce well-lit spaces that stay in a comfortable
temperature range. Socrates' Megaron House is a classic example of passive solar
design. The most recent approaches to solar design use computer modeling tying
together solar lighting, heating and ventilation systems in an integrated solar design
package. Active solar equipment such as pumps, fans and switchable windows can
complement passive design and improve system performance.
~ 8 ~
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1.2.2 AGRICULTURE AND HORTICULTURE
1.4 Farm house
Agriculture and horticulture seek to optimize the capture of solar energy in order
to optimize the productivity of plants. Techniques such as timed planting cycles,
tailored row orientation, staggered heights between rows and the mixing of plant
varieties can improve crop yields. While sunlight is generally considered a
plentiful resource, the exceptions highlight the importance of solar energy to
agriculture. During the short growing seasons of the Little Ice Age, French and
English farmers employed fruit walls to maximize the collection of solar energy.
These walls acted as thermal masses and accelerated ripening by keeping plants
warm. Early fruit walls were built perpendicular to the ground and facing south,
but over time, sloping walls were developed to make better use of sunlight. In
1699, Nicolas Fatio de Duillier even suggested using a tracking mechanism which
could pivot to follow the Sun. [26] Applications of solar energy in agriculture aside
from growing crops include pumping water, drying crops, brooding chicks and
drying chicken manure. More recently the technology has been embraced by
vinters, who use the energy generated by solar panels to power grape presses.
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~9~
1.2.3 SOLAR LIGHTING
Daylighting features such as this oculus at
the top of the Pantheon, in Rome, Italy have
been in use since antiquity. The history of
lighting is dominated by the use of natural
light. The Romans recognized a right to
light as early as the 6th century and
1.5 Solar Lighting English law echoed these
judgments with the Prescription Act of 1832. In the 20th century artificial lighting
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became the main source of interior illumination but daylighting techniques and
hybrid solar lighting solutions are ways to reduce energy consumption.
Daylighting systems collect and distribute sunlight to provide interior illumination.This passive technology directly offsets energy use by replacing artificial lighting,
and indirectly offsets non-solar energy use by reducing the need for air-
conditioning. [34] Although difficult to quantify, the use of natural lighting also
offers physiological and psychological benefits compared to artificial lighting.
Hybrid solar lighting is an active solar method of providing interior illumination.
HSL systems collect sunlight using focusing mirrors that track the Sun and use
optical fibers to transmit it inside the building to supplement conventional lighting.
~ 10 ~
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1.2.4 WATER HEATING
Solar hot water systems use sunlight to heat water.
In low geographical latitudes (below 40 degrees)
from 60 to 70% of the domestic hot water use with
temperatures up to 60 C can be provided by solar
heating systems. The most common types of solar
water heaters are evacuated tube collectors (44%)
and glazed flat plate collectors (34%) generally
used for
1.6 water heating domestic hot water; and
unglazed plastic collectors (21%) used mainly to heat swimming pools.
As of 2007, the total installed capacity of solar hot water systems is approximately
154 GW. China is the world leader in their deployment with 70 GW installed as of
2006 and a long term goal of 210 GW by 2020. Israel and Cyprus are the per capita
leaders in the use of solar hot water systems with over 90% of homes using them. In
the United States, Canada and Australia heating swimming pools is the dominant
application of solar hot water with an installed capacity of 18 GW as of 2005.
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~ 11 ~
1.2.5 SOLAR COOKER
The Solar Bowl in Auroville, India,
concentrates sunlight on a movable receiver to
produce steam for cooking.
Solar cookers use sunlight for cooking, drying
and pasteurization. They can be grouped into
three
1.7 solar cooker broad categories: box
cookers, panel cookers and reflector cookers. The simplest solar cooker is the box
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cooker first built by Horace de Saussure in 1767. A basic box cooker consists of an
insulated container with a transparent lid. It can be used effectively with partially
overcast skies and will typically reach temperatures of 90-150 C.[58] Panel
cookers use a reflective panel to direct sunlight onto an insulated container and
reach temperatures comparable to box cookers. Reflector cookers use various
concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking
container. These cookers reach temperatures of 315 C and above but require direct
light to function properly and must be repositioned to track the Sun. The solar bowl
is a concentrating technology employed by the Solar Kitchen in Auroville,
Pondicherry, India, where a stationary spherical reflector focuses light along a lineperpendicular to the sphere's interior surface, and a computer control system moves
the receiver to intersect this line. Steam is produced in the receiver at temperatures
reaching 150 C and then used for process heat in the kitchen.
~12~
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1.3 ENERGY STORAGE METHODS
Solar Two's thermal storage system generated electricity during cloudy weather
and at night.
Solar energy is not available at night, and energy storage is an important issue
because modern energy systems usually assume continuous availability of energy.
Thermal mass systems can store solar energy in the form of heat at domestically
useful temperatures for daily or seasonal durations. Thermal storage systems
generally use readily available materials with high specific heat capacities such as
water, earth and stone. Well-designed systems can lower peak demand, shift time-
of-use to off-peak hours and reduce overall heating and cooling requirements.
Phase change materials such as paraffin wax and Glauber's salt are another thermal
storage media. These materials are inexpensive, readily available, and can deliver
domestically useful temperatures (approximately 64 C). The "Dover House" (in
Dover, Massachusetts) was the first to use a Glauber's salt heating system, in 1948.
Solar energy can be stored at high temperatures using molten salts. Salts are an
effective storage medium because they are low-cost, have a high specific heat
capacity and can deliver heat at temperatures compatible with conventional power
systems. The Solar Two used this method of energy storage, allowing it to store
1.44 TJ in its 68 m3
storage tank with an annual storage efficiency of about 99%.
Off-grid PV systems have traditionally used rechargeable batteries to store excess
electricity. With grid-tied systems, excess electricity can be sent to the transmission
grid. Net metering programs give these systems a credit for the electricity they
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deliver to the grid. This credit offsets electricity provided from the grid when the
system cannot meet demand, effectively using the grid as a storage mechanism.
~ 13 ~
1.4 DEVELOPMENT
Nellis Solar Power Plant in the United States, the largest photovoltaic power plant
in North America.
Beginning with the surge in coal use which accompanied the Industrial Revolution,
energy consumption has steadily transitioned from wood and biomass to fossil
fuels. The early development of solar technologies starting in the 1860s was driven
by an expectation that coal would soon become scarce. However development of
solar technologies stagnated in the early 20th century in the face of the increasing
availability, economy, and utility of coal and petroleum.
The 1973 oil embargo and 1979 energy crisis caused a reorganization of energy
policies around the world and brought renewed attention to developing solar
technologies.[104] [105] Deployment strategies focused on incentive programs
such as the Federal Photovoltaic Utilization Program in the US and the Sunshine
Program in Japan. Other efforts included the formation of research facilities in the
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US (SERI, now NREL), Japan (NEDO), and Germany (Fraunhofer Institute for
Solar Energy Systems ISE).
~ 14-
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SOLAR TRACKER
CONTENTS:
1. HISTORY2. TYPES OF SOLAR TRACKER
1. HORIZONTAL AXLE
2. VERTICAL AXLE
3. ALTITUDE-AZIMUTH
4. TWO-AXIS MOUNT
5. MULTI-MIRROR REFLECTIVE UNIT
2.3 DRIVE TYPES
1. ACTIVE TRACKER
2. PASSIVE TRACKER
3. CHRONOLOGICAL TRACKER
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4. THIN-FILM SOLAR TRACKER
15
2.1 HISTORY A solar tracker is a device for orienting a daylighting reflector, solar
photovoltaic panel or concentrating solar reflector or lens toward the sun. The sun's
position in the sky varies both with the seasons and time of day as the sun moves
across the sky. Solar powered equipment works best when pointed at or near the
sun, so a solar tracker can increase the effectiveness of such equipment over any
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fixed position, at the cost of additional system complexity. There are many types of
solar trackers, of varying costs, sophistication, and performance. One well-known
type of solar tracker is the heliostat, a movable mirror that reflects the moving sun to
a fixed location, but many other approaches are used as well.
The required accuracy of the solar tracker depends on the application.
Concentrators, especially in solar cell applications, require a high degree of
accuracy to ensure that the concentrated sunlight is directed precisely to the
powered device, which is at (or near) the focal point of the reflector or lens.
Typically concentrator systems will not work at all without tracking, so at least
single-axis tracking is mandatory. Very large power plants or high temperature
materials research facilities using multiple ground-mounted mirrors and an absorber
target require very high precision similar to that used for solar telescopes.
Non-concentrating applications require less accuracy, and many work without any
tracking at all. However, tracking can substantially improve both the amount of
total power produced by a system and that produced during critical system demand
periods (typically late afternoon in hot climates) The use of trackers in non-
concentrating applications is usually an engineering decision based on economics.
Compared to photovoltaics, trackers can be inexpensive. This makes them
especially effective for photovoltaic systems using high-efficiency (and thus
expensive) panels.
For low-temperature solar thermal applications, trackers are not usually used,
owing to the high expense of trackers compared to adding more collector area and
the more restricted solar angles required for Winter performance, which influence
the average year-round system capacity.
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~ 16 ~
~
2.2 TYPES OF SOLAR TRACKER
Solar trackers may be active or passive and may be single axis or dual axis.
Single axis trackers usually use a polar mount for maximum solar efficiency.
Single axis trackers will usually have a manual elevation (axis tilt) adjustment on a
second axis which is adjusted on regular intervals throughout the year.
Compared to a fixed mount, a single axis tracker increases annual output by
approximately 30%, and a dual axis tracker an additional 6%.
There are two types of dual axis trackers, polar and altitude-azimuth.
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~ 17 ~
2.2.1 HORIZONTAL AXLE
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2.1 Horizontal Axle
Several manufacturers can deliver single axis horizontal trackers which may be
oriented by either passive or active mechanisms, depending upon manufacturer. In
these, a long horizontal tube is supported on bearings mounted upon pylons or
frames. The axis of the tube is on a North-South line. Panels are mounted upon the
tube, and the tube will rotate on its axis to track the apparent motion of the sun
through the day. Since these do not tilt toward the equator they are not especially
effective during winter mid day (unless located near the equator), but add a
substantial amount of productivity during the spring and summer seasons when the
solar path is high in the sky. These devices are less effective at higher latitudes.
The principal advantage is the inherent robustness of the supporting structure and
the simplicity of the mechanism. Since the panels are horizontal, they can be
compactly placed on the axle tube without danger of self-shading and are also
readily accessible for cleaning. For active mechanisms, a single control and motor
may be used to actuate multiple rows of panels. Manufacturers include Array
Technologies, Inc. Wattsun Solar Trackers (gear driven active), Zomeworks
(passive) and Power light (active).
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~ 18-