Solar Tracking1

8/2/2019 Solar Tracking1

1/35

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


2/35

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


3/35

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


4/35

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.


5/35

1.

[

~-


6/35

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


7/35

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.


8/35

~ .s ~

> ' I ) > )

) )


9/35

i

Coal 2 5% Gas 2 3%

I


10/35

Biomass 4% Hydrouclear>A>

fN


11/35

ir r

olar heat 0.5% Wind 0.3%

*

Geothermal

0.2%

B

io

f

u

e

l

s


12/35

0

.

2

%

S

o

l

a

r

p

h

o

t

o

v

o

l


13/35

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


14/35

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~


15/35

7.2 TW

32 TW

86,000 TW

Hydro Geothermal


16/35

870 TW

15 TW

Glob

al Solar Wind

Consumption 1.2 Use of Solar

Energy in the World


17/35

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


18/35

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


19/35

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 ~


20/35

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.


21/35

~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


22/35

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 ~


23/35

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.


24/35

~ 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


25/35

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~


26/35

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


27/35

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


28/35

US (SERI, now NREL), Japan (NEDO), and Germany (Fraunhofer Institute for

Solar Energy Systems ISE).

~ 14-


29/35

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


30/35

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


31/35

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.


32/35

~ 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.


33/35

~ 17 ~

2.2.1 HORIZONTAL AXLE


34/35

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).


35/35

~ 18-

Solar Tracking1

Documents

Transcript of Solar Tracking1