Air Cooler Solar 2011 Sa Poly Final

7/23/2019 Air Cooler Solar 2011 Sa Poly Final

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LITTLE FLOWER POLYTECHNIC COLLEGE,

Porur, Chennai-600 116.

TITLE NAME :

Fabrication of Solar Air Cooler

PROJECT MEMBERS REG. No.

V. ANAND 2512607

P. ASHOK KUMAR 2512609

S. RAMEEZ RAJA 2512631

M. RAMESH 2512632

B. SANJAY 2512635

J. SHANMUGAM 2512641

PROJECT GUIDE

H.O.D. Mr. B. SELVAM


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A.M.K TECHNOLOGICAL POLYTECHNIC COLLEGE

CHENNAI- BANGALORE ROAD

SEMBARAMBAKKAM

CHENNAI 602103

BONAFIDE CERTIFICATE

This is to certify that this Project work on

solar air cooler

submitted by . Reg. No.

in partial fulfillment for the award of

DIPLOMA IN MECHANICAL ENGINEERING

This is the bonafide record of work carried out by him under our superision

during the year !"##

$ubmitted for the %ia&oce e'am held on ..

()*+ ,- +)P*RT)NT PR,/)0T 123+)

3NT)RN*4 )5*3N)R )5T)RN*4 )5*3N)R


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CKNOWLEDGEMENT


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ACKNOWLEDGEMENT

*t the outset6 we would like to emphasi7e our sincere thanks to the

Principal Mr. R.J. KUMAR M.E.F.I.E M.I.S.T.Efor encouragement and

aluable adice.

we thank our )s8uired (ead of +epartment Mr. R. RAJKUMAR M.E.for

presenting his felications on us.

9e are grateful on our )ntourages Mr. S. SURESH B..E. -or guiding in

arious aspects of the project making it a grand success.

9e also owe our sincere thanks to all staff members of the echanical

+epartment

2ltimately6 we e'tend our thanks to all who had rendered their co&

operation for the success of the project.


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CONTENTS


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CONTENTS

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INTRODUCTION


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INTRODUCTION ABOUT THE PROJECT

This is a self E assessment test on the part of the students to assess his

competency in creatiity.

+uring the course of study6 the student is put on a sound theoretical

foundation of arious mechanical engineering subjects and of course6 to a

satisfactory e'tent. ,pportunities are made aailable to him to work on

different kinds of machines6 so that he is e'posed to arious kinds of

manufacturing process.

*s a students learn more and more his hold on production technology

becomes stronger. (e attains a stage of perfection6 when he himself is able

to design and fabricate a deice.

This is the project work. That is the testimony for the strenuous

training6 which the student had in the institute. This assures that he is no

more a student6 he is an engineer.

This report discuses the necessity of the project and arious aspects of

planning 6design6 selection of materials6 fabrication6 erection6 estimation and

testing.


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SYNPOSIS


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SYNPOSIS

The solar panel is conerting sun rays to the )lectricity by Photo&

%oltaic )ffect. This electric power is stored in a #!&%olt battery. Dattery

+.0. power is used to run the +.0. motor and +.0. water pump. Dlock

diagram6 Photo&oltaic )ffect and major components of our project are

Dattery6 +.0. otor -an6 #! %olt +0 Pump and #! +0 solar panel and core

unit.

The +.0. motor is coupled with impeller blades. The +.0. motor runs

during the air cooler button ,N6 the impeller blades starts rotating. The

water pump is used to circulate the water to the blower unit.

The forced air is flow through the water which is sprayed by water

pump6 so that the cold air produced. The solar panel stand and complete

diagram are gien below.


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CONSTRUCTION


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CONSTRUCTION

3t consists of a bo' shaped hollow structure to a si7e of


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WORKING

PRINCIPLE


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WORKING PRINCIPLE

There are three circuits and one control panel inoled6

#. 9ater circuit

!. *ir circuit

;. $,4*R P*N)4 circuit


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AIR CIRCUIT!

The outside temperature of the cooler is reduced to lower leel and

the cooling effect is achieed by the supplying air mist from the cooler

forced from the fan blower. The sprayed water is collected in a sump at the

bottom of the cooler unit..


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DESCRIPTION OFSOLAR CELL


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* "#$%r &'$$ Galso called ()#*#+#$*%,& &'$$H is a solid state deice that

conerts the energy of sunlightdirectly into electricityby the ()#*#+#$*%,&

''&*. *ssemblies of cells are used to make solar modules6 also known as

solar panels. The energy generated from these solar modules6 referred to as

solar power6 is an e'ample ofsolar energy.

Photovoltaicsis the field of technology and research related to the practical

application of photooltaic cells in producing electricity from light6 though it

is often used specifically to refer to the generation of electricity from

sunlight.

0ells are described as photovoltaic cells when the light source is not

necessarily sunlight. These are used for detecting light or other

electromagnetic radiation near the isible range6 for e'ample infrared

detectors6 or measurement of light intensity.

C#*'*"

IhideJ

# (istory of solar cells

o #.# Dell produces the first practical cell

o #.! DermanKs price reductions

o #.; Naigation market

o #.< -urther improements

! *pplications ; Theory

< )fficiency

> 0ost

? aterials
http://en.wikipedia.org/wiki/Solid_statehttp://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Photovoltaic_effecthttp://en.wikipedia.org/wiki/Photovoltaic_effecthttp://en.wikipedia.org/wiki/Solar_modulehttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Solar_energyhttp://en.wikipedia.org/wiki/Photovoltaicshttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Infrared_detectorhttp://en.wikipedia.org/wiki/Infrared_detectorhttp://en.wikipedia.org/wiki/Solar_cellhttp://en.wikipedia.org/wiki/Solar_cell#History_of_solar_cellshttp://en.wikipedia.org/wiki/Solar_cell#Bell_produces_the_first_practical_cellhttp://en.wikipedia.org/wiki/Solar_cell#Berman.27s_price_reductionshttp://en.wikipedia.org/wiki/Solar_cell#Navigation_markethttp://en.wikipedia.org/wiki/Solar_cell#Further_improvementshttp://en.wikipedia.org/wiki/Solar_cell#Applicationshttp://en.wikipedia.org/wiki/Solar_cell#Theoryhttp://en.wikipedia.org/wiki/Solar_cell#Efficiencyhttp://en.wikipedia.org/wiki/Solar_cell#Costhttp://en.wikipedia.org/wiki/Solar_cell#Materialshttp://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Photovoltaic_effecthttp://en.wikipedia.org/wiki/Photovoltaic_effecthttp://en.wikipedia.org/wiki/Solar_modulehttp://en.wikipedia.org/wiki/Solar_powerhttp://en.wikipedia.org/wiki/Solar_energyhttp://en.wikipedia.org/wiki/Photovoltaicshttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Infrared_detectorhttp://en.wikipedia.org/wiki/Infrared_detectorhttp://en.wikipedia.org/wiki/Solar_cellhttp://en.wikipedia.org/wiki/Solar_cell#History_of_solar_cellshttp://en.wikipedia.org/wiki/Solar_cell#Bell_produces_the_first_practical_cellhttp://en.wikipedia.org/wiki/Solar_cell#Berman.27s_price_reductionshttp://en.wikipedia.org/wiki/Solar_cell#Navigation_markethttp://en.wikipedia.org/wiki/Solar_cell#Further_improvementshttp://en.wikipedia.org/wiki/Solar_cell#Applicationshttp://en.wikipedia.org/wiki/Solar_cell#Theoryhttp://en.wikipedia.org/wiki/Solar_cell#Efficiencyhttp://en.wikipedia.org/wiki/Solar_cell#Costhttp://en.wikipedia.org/wiki/Solar_cell#Materialshttp://en.wikipedia.org/wiki/Solid_state


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o ?.# 0rystalline silicon

o ?.! Thin films

?.!.# 0admium telluride solar cell

?.!.! 0opper&3ndium $elenide

?.!.; 1allium arsenide multijunction

?.!.< 4ight&absorbing dyes G+$$0H

?.!.> ,rganicFpolymer solar cells

?.!.? $ilicon thin films

@ anufacture

A 4ifespan

C Research topics

#" anufacturers and certificationo #".# 0hina

o #".! 2nited $tates

## $ee also

#! References

#; )'ternal links

H,"*#r/ # "#$%r &'$$"

Main article: Timeline of solar cells

The term LphotooltaicL comes from the 1reekM GphsH meaning LlightL6

and LoltaicL6 meaning electric6 from the name of the 3talianphysicist %olta6

after whom a unit of electro&motie force6 the olt6 is named. The term

Lphoto&oltaicL has been in use in )nglish since #A


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e'tremely thin layer of goldto form the junctions. The deice was only

around #O efficient. 3n #AAA Russian physicist *leksandr $toletobuilt the

firstphotoelectric cellGbased on the outerphotoelectric effectdiscoered by

(einrich (ert7earlier in #AA@H. *lbert )insteine'plained the photoelectric

effect in #C"> for which he receied the Nobel pri7e in Physics in #C!#.

Russell ,hlpatented the modern junction semiconductor solar cell in #C


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was higher than any competing technology. (oweer6 this success was also

the reason for slow progressQ space users were willing to pay anything for

the best possible cells6 there was no reason to inest in lower&cost solutions

if this would reduce efficiency. 3nstead6 the price of cells was determined

largely by the semiconductor industryQ their moe to integrated circuits in

the #C?"s led to the aailability of larger boulesat lower relatie prices. *s

their price fell6 the price of the resulting cells did as well. (oweer these

effects were limited6 and by #C@# cell costs were estimated to be #"" a

watt.I>J

B'r%" (r,&' r'&*,#"

3n the late #C?"s6 )lliot Derman was inestigating a new method for

producing the silicon feedstock in a ribbon process. (oweer6 he found little

interest in the project and was unable to gain the funding needed to deelop

it. 3n a chance encounter6 he was later introduced to a team at )''onwho

were looking for projects ;" years in the future. The group had concluded

that electrical power would be much more e'pensie by !"""6 and felt that

this increase in price would make new alternatie energy sources more

attractie6 and solar was the most interesting among these. 3n #C?C6 Derman

joined the 4inden6 New /ersey )''on lab6 $olar Power 0orporation G$P0H.I?J

(is first major effort was to canas the potential market to see what possible

uses for a new product were6 and they 8uickly found that if the dollars per

wattwas reduced from then&current #""Fwatt to about !"Fwatt there was

significant demand. =nowing that his ribbon concept would take years todeelop6 the team started looking for ways to hit the !" price point using

e'isting materials.I?J
http://en.wikipedia.org/wiki/Integrated_circuithttp://en.wikipedia.org/wiki/Boulehttp://en.wikipedia.org/wiki/Solar_cell#cite_note-p50-4http://en.wikipedia.org/wiki/Exxonhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-p53-5http://en.wikipedia.org/wiki/Dollars_per_watthttp://en.wikipedia.org/wiki/Dollars_per_watthttp://en.wikipedia.org/wiki/Solar_cell#cite_note-p53-5http://en.wikipedia.org/wiki/Integrated_circuithttp://en.wikipedia.org/wiki/Boulehttp://en.wikipedia.org/wiki/Solar_cell#cite_note-p50-4http://en.wikipedia.org/wiki/Exxonhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-p53-5http://en.wikipedia.org/wiki/Dollars_per_watthttp://en.wikipedia.org/wiki/Dollars_per_watthttp://en.wikipedia.org/wiki/Solar_cell#cite_note-p53-5


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The first improement was the reali7ation that the e'isting cells were based

on standard semiconductor manufacturing process6 een though that was not

ideal. This started with the boule6 cutting it into disks called wafers6

polishing the wafers6 and then6 for cell use6 coating them with an anti&

reflectie layer. Derman noted that the rough&sawn wafers already had a

perfectly suitable anti&reflectie front surface6 and by printing the electrodes

directly on this surface6 two major steps in the cell processing were

eliminated. The team also e'plored ways to improe the mounting of the

cells into arrays6 eliminating the e'pensie materials and hand wiring used

in space applications with aprinted circuit boardon the back6 acrylic plastic

on the front6 and silicone based glue between the two potting the cells. Dut

the largest improement in price point was DermanKs reali7ation that e'istingsilicon was effectiely Ltoo goodL for solar cell useQ the minor imperfections

that would ruin a boule Gor indiidual waferH for electronics would hae little

effect in the solar application.I@J

Putting all of these changes into practice6 the company started buying up

LrejectL silicon from e'isting manufacturers at ery low cost. Dy using the

largest wafers aailable6 thereby reducing the amount of wiring for a gien

panel area6 and packaging them into panels using their new methods6 by

#C@; $P0 was producing panels at #" and selling them at !"6 a fie&fold

decrease in prices in two years.

N%+,4%*,# %r5'*

$P0 approached companies making buoys as a natural market for theirproducts6 but found a curious situation. The primary company in the

business was *utomatic Power6 a battery manufacturer. Reali7ing that solar

cells might eat into their battery profits6 *utomatic purchased the rights to

earlier solar cell designs and suppressed them. $eeing there was no interest
http://en.wikipedia.org/wiki/Printed_circuit_boardhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-p54-6http://en.wikipedia.org/wiki/Printed_circuit_boardhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-p54-6


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there6 $P0 turned to Tideland $ignal6 another battery company formed by

e'&*utomatic managers. Tideland introduced a solar&powered buoy and was

soon ruining *utomaticKs business.

The timing could not be betterQ the rapid increase in the number of offshore

oil platformsand loading facilities produced an enormous market among theoil companies. *s TidelandKs fortunes improed6 *utomatic started looking

for their own supply of solar panels. They found Dill :erks of $olar Power

3nternational G$P3H in 0alifornia6 who was looking for a market. $P3 was

soon bought out by one of its largest customers6 the *R0, oil giant6

forming *R0, $olar. *R0, $olarKs factory in 0amarillo6 0aliforniawas the

first dedicated to building solar panels6 and has been in continual operation

from its purchase by *R0, in #C@@ to this day.

This market6 combined with the #C@; oil crisis6 led to a curious situation. ,il

companies were now cash&flush due to their huge profits during the crisis6

but were also acutely aware that their future success would depend on some

other form of power. ,er the ne't few years6 the major oil companies

started a number of solar firms6 and were for decades the largest producers

of solar panels. )''on6 *R0,6 $hell6 *moco Glater purchased by DPH and

obil all had major solar diisions during the #C@"s and A"s. Technology

companies also had some inestment6 including 1eneral )lectric6 otorola6

3D6 Tyco and R0*.IAJ

Fr*)'r ,(r#+''*"

3n the time since DermanKs work6 improements hae brought production

costs down under # a watt6 with wholesale costs on the order of !.

LDalance of systemL costs are now more than the panels themseles6 with
http://en.wikipedia.org/w/index.php?title=Offshore_oil_platform&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Offshore_oil_platform&action=edit&redlink=1http://en.wikipedia.org/wiki/ARCOhttp://en.wikipedia.org/wiki/Camarillo,_Californiahttp://en.wikipedia.org/wiki/1973_oil_crisishttp://en.wikipedia.org/wiki/Solar_cell#cite_note-7http://en.wikipedia.org/w/index.php?title=Offshore_oil_platform&action=edit&redlink=1http://en.wikipedia.org/w/index.php?title=Offshore_oil_platform&action=edit&redlink=1http://en.wikipedia.org/wiki/ARCOhttp://en.wikipedia.org/wiki/Camarillo,_Californiahttp://en.wikipedia.org/wiki/1973_oil_crisishttp://en.wikipedia.org/wiki/Solar_cell#cite_note-7


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large commercial arrays falling to around > a watt6 fully commissioned6 in

!"#".

*s the semiconductor industry moed to eer&larger boules6 older e8uipment

became aailable at fire&sale prices. 0ells hae grown in si7e as older

e8uipment became aailable on the surplus marketQ *R0, $olarKs originalpanels used cells with ! to < inch diameter. Panels in the #CC"s and early

!"""s generally used > inch wafers6 and since !""A almost all new panels

use ? inch cells. *nother major change was the moe to polycrystalline

silicon. This material has less efficiency6 but is less e'pensie to produce in

bulk. The widespread introduction of flat screen teleisionsin the late #CC"s

and early !"""s led to the wide aailability of large sheets of high&8uality

glass6 used on the front of the panels.

,ther technologies hae also come to market. -irst $olar has grown to

become the largest panel manufacturer6 in terms of yearly power produced6

using a thin&film cell sandwiched between two layers of glass. This was the

first product to beat # a watt for production costs. ICJ$ince then a glut of

polycrystalline silicon has pushed prices of conentional panels into the

same range.

A(($,&%*,#"
http://en.wikipedia.org/wiki/Flat_screen_televisionhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-8http://en.wikipedia.org/wiki/Flat_screen_televisionhttp://en.wikipedia.org/wiki/First_Solarhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-8


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Polycrystallinephotooltaic cells laminated to backing material in a module

Polycrystalline photooltaic cells

Main article:photovoltaic system

$olar cells are often electrically connected and encapsulated as a #$'.

Photooltaic modules often hae a sheet of glass on the front Gsun upH side6

allowing light to pass while protecting the semiconductor wafers from

abrasion and impact due to wind&drien debris6 rain6 hail6 et cetera. $olar

cells are also usually connected in seriesin modules6 creating an additie

oltage. 0onnecting cells in parallel will yield a higher current. odules are

then interconnected6 in series or parallel6 or both6 to create an %rr%/with the

desired peak +0 oltage and current.
http://en.wikipedia.org/wiki/Polycrystalline_siliconhttp://en.wikipedia.org/wiki/Photovoltaic_systemhttp://en.wikipedia.org/wiki/Wafer_(electronics)http://en.wikipedia.org/wiki/Rainhttp://en.wikipedia.org/wiki/Hailhttp://en.wikipedia.org/wiki/Series_and_parallel_circuitshttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/File:Solar_panel.pnghttp://en.wikipedia.org/wiki/File:Solar_panel.pnghttp://en.wikipedia.org/wiki/File:Polycristalline-silicon-wafer_20060626_568.jpghttp://en.wikipedia.org/wiki/File:Polycristalline-silicon-wafer_20060626_568.jpghttp://en.wikipedia.org/wiki/Polycrystalline_siliconhttp://en.wikipedia.org/wiki/Photovoltaic_systemhttp://en.wikipedia.org/wiki/Wafer_(electronics)http://en.wikipedia.org/wiki/Rainhttp://en.wikipedia.org/wiki/Hailhttp://en.wikipedia.org/wiki/Series_and_parallel_circuitshttp://en.wikipedia.org/wiki/Voltage


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To make practical use of the solar&generated energy6 the electricity is most

often fed into the electricity grid using inerters Ggrid&connected

photooltaic systemsHQ in stand&alone systems6 batteries are used to store the

energy that is not needed immediately. $olar panels can be used to power or

recharge portable deices.

T)'#r/

Main article: Theory of solar cell

The solar cell works in three steps

#. Photons in sunlight hit the solar panel and are absorbed by

semiconducting materials6 such as silicon.

!. )lectronsGnegatiely chargedH are knocked loose from their atoms6

allowing them to flow through the material to produce electricity. +ue

to the special composition of solar cells6 the electrons are only

allowed to moe in a single direction.

;. *n array of solar cells conerts solar energy into a usable amount of

direct currentG+0H electricity.

E,&,'&/

Main article: Solar cell efficiency

The efficiency of a solar cell may be broken down into reflectance

efficiency6 thermodynamic efficiency6 charge carrier separation efficiency

and conductie efficiency. The oerall efficiency is the product of each of

these indiidual efficiencies.

+ue to the difficulty in measuring these parameters directly6 other

parameters are measured instead thermodynamic efficiency6 8uantum
http://en.wikipedia.org/wiki/Photovoltaic_systemhttp://en.wikipedia.org/wiki/Theory_of_solar_cellhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Electronshttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Solar_cell_efficiencyhttp://en.wikipedia.org/wiki/Quantum_efficiency_of_a_solar_cellhttp://en.wikipedia.org/wiki/Photovoltaic_systemhttp://en.wikipedia.org/wiki/Theory_of_solar_cellhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Sunlighthttp://en.wikipedia.org/wiki/Electronshttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Solar_cell_efficiencyhttp://en.wikipedia.org/wiki/Quantum_efficiency_of_a_solar_cell


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efficiency6 %,0ratio6 and fill factor. Reflectance losses are a portion of the

8uantum efficiency under Le'ternal 8uantum efficiencyL. Recombination

losses make up a portion of the 8uantum efficiency6 %,0ratio6 and fill factor.

Resistie losses are predominantly categori7ed under fill factor6 but also

make up minor portions of the 8uantum efficiency6 %,0ratio.

0rystalline silicon deices are now approaching the theoretical limiting

efficiency of !CO.

C#"*

The cost of a solar cell is gien per unit of peak electrical power.

anufacturing costs necessarily including the cost of energy re8uired for

manufacture. $olar&specific feed in tariffs ary worldwide6 and een state by

state within arious countries.I#"J$uch feed&in tariffs can be highly effectie

in encouraging the deelopment of solar power projects.

(igh&efficiency solar cells are of interest to decrease the cost of solar energy.

any of the costs of a solar power plant are proportional to the area of the

plantQ a higher efficiency cell may reduce area and plant cost6 een if thecells themseles are more costly. )fficiencies of bare cells6 to be useful in

ealuating solar power plant economics6 must be ealuated under realistic

conditions. The basic parameters that need to be ealuated are the short

circuit current6 open circuit oltage.I##J

The chart at the right illustrates the best laboratory efficiencies obtained for

arious materials and technologies6 generally this is done on ery small6 i.e.

one s8uare cm6 cells. 0ommercial efficiencies are significantly lower.
http://en.wikipedia.org/wiki/Quantum_efficiency_of_a_solar_cellhttp://en.wikipedia.org/wiki/Fill_factorhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-9http://en.wikipedia.org/wiki/Solar_cell#cite_note-10http://en.wikipedia.org/wiki/Quantum_efficiency_of_a_solar_cellhttp://en.wikipedia.org/wiki/Fill_factorhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-9http://en.wikipedia.org/wiki/Solar_cell#cite_note-10


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* $#-"* ()#*#+#$*%,& &'$$ is a thin&film cell intended to produce

electrical energy at a price competitie with traditional Gfossil fuels and

nuclear powerH energy sources. This includes second and third generation

photooltaic cells6 that is cheaper than first generation Gcrystalline silicon

cells6 also called waferor bulk cellsH.

1rid parity6 the point at which photooltaic electricity is e8ual to or cheaper

than grid power6 can be reached using low cost solar cells. 3t is achieed first

in areas with abundant sun and high costs for electricity such as in 0alifornia

and /apan.I#!J1rid parity has been reached in (awaiiand other islands that

otherwise use diesel fuel to produce electricity. 1eorge 9. Dush had set

!"#> as the date for grid parity in the 2$*.I#;JI#


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The price of solar panels fell steadily for


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,ther materials are made as thin&films layers6 organic dyes6 and organic

polymersthat are deposited on supporting substrates. * third group are made

from nanocrystals and used as 8uantum dots Gelectron&confined

nanoparticlesH. $ilicon remains the only material that is well&researched in

both bulkand thin-filmforms.

Cr/"*%$$,' ",$,

Main articles:Monocrystalline silicon, Polycrystalline silicon, Silicon, and

list of silicon producers

Dasic structure of a silicon based solar cell and its working mechanism.

Dy far6 the most prealent bulkmaterial for solar cells is crystallinesilicon

Gabbreiated as a group as c-SiH6 also known as Lsolar grade siliconL. Dulk

silicon is separated into multiple categories according to crystallinity andcrystal si7e in the resulting ingot6 ribbon6 or wafer.

#. monocrystalline silicon Gc&$iH often made using the 07ochralski

process. $ingle&crystal wafer cells tend to be e'pensie6 and because
http://en.wikipedia.org/wiki/Thin_filmshttp://en.wikipedia.org/wiki/Dyehttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Supporting_substratehttp://en.wikipedia.org/wiki/Nanocrystalline_solar_cellhttp://en.wikipedia.org/wiki/Quantum_dothttp://en.wikipedia.org/wiki/Nanoparticlehttp://en.wikipedia.org/wiki/Monocrystalline_siliconhttp://en.wikipedia.org/wiki/Polycrystalline_siliconhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/List_of_silicon_producershttp://en.wikipedia.org/wiki/Crystallinehttp://en.wikipedia.org/wiki/Ingothttp://en.wikipedia.org/wiki/Ribbonhttp://en.wikipedia.org/wiki/Wafer_(electronics)http://en.wikipedia.org/wiki/Monocrystalline_siliconhttp://en.wikipedia.org/wiki/Czochralski_processhttp://en.wikipedia.org/wiki/Czochralski_processhttp://en.wikipedia.org/wiki/File:Silicon_Solar_cell_structure_and_mechanism.svghttp://en.wikipedia.org/wiki/File:Silicon_Solar_cell_structure_and_mechanism.svghttp://en.wikipedia.org/wiki/Thin_filmshttp://en.wikipedia.org/wiki/Dyehttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Supporting_substratehttp://en.wikipedia.org/wiki/Nanocrystalline_solar_cellhttp://en.wikipedia.org/wiki/Quantum_dothttp://en.wikipedia.org/wiki/Nanoparticlehttp://en.wikipedia.org/wiki/Monocrystalline_siliconhttp://en.wikipedia.org/wiki/Polycrystalline_siliconhttp://en.wikipedia.org/wiki/Siliconhttp://en.wikipedia.org/wiki/List_of_silicon_producershttp://en.wikipedia.org/wiki/Crystallinehttp://en.wikipedia.org/wiki/Ingothttp://en.wikipedia.org/wiki/Ribbonhttp://en.wikipedia.org/wiki/Wafer_(electronics)http://en.wikipedia.org/wiki/Monocrystalline_siliconhttp://en.wikipedia.org/wiki/Czochralski_processhttp://en.wikipedia.org/wiki/Czochralski_process


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they are cut from cylindrical ingots6 do not completely coer a s8uare

solar cell module without a substantial waste of refined silicon. (ence

most c-Sipanels hae uncoered gaps at the four corners of the cells.

!. Poly- or multicrystalline siliconGpoly&$i or mc&$iH made from cast

s8uare ingots S large blocks of molten silicon carefully cooled and

solidified. Poly&$i cells are less e'pensie to produce than single

crystal silicon cells6 but are less efficient. 2$ +,)data shows that

there were a higher number of multicrystalline sales than

monocrystalline silicon sales.

;. ibbon siliconI#AJ is a type of multicrystalline silicon it is formed by

drawing flat thin films from molten silicon and results in a

multicrystalline structure. These cells hae lower efficiencies thanpoly&$i6 but sae on production costs due to a great reduction in

silicon waste6 as this approach does not re8uire sawingfrom ingots.

*nalysts hae predicted that prices of polycrystalline silicon will drop as

companies build additional polysilicon capacity 8uicker than the industrys

projected demand. ,n the other hand6 the cost of producing upgraded

metallurgical&grade silicon6 also known as 21 $i6 can potentially be one&

si'th that of makingpolysilicon.I#CJ

anufacturers of wafer&based cells hae responded to thin&film lower prices

with rapid reductions in silicon consumption. *ccording to /ef Poortmans6

director of 3)0Ks organic and solar department6 current cells use between

eight and nine grams of silicon per watt of power generation6 with wafer

thicknesses in the neighborhood of ".!"" mm. *t !""A springKs 3)))

Photooltaic $pecialistsK 0onference GP%$K"AH6 /ohn 9ohlgemuth6 staff

scientist at DP $olar6 reported that his company has 8ualified modules based

on ".#A" mm thick wafers and is testing processes for ".#? mm wafers cut
http://en.wikipedia.org/wiki/Multicrystalline_siliconhttp://en.wikipedia.org/wiki/US_DOEhttp://en.wikipedia.org/wiki/Ribbon_siliconhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-17http://en.wikipedia.org/wiki/Moltenhttp://en.wikipedia.org/wiki/Multicrystallinehttp://en.wikipedia.org/w/index.php?title=Silicon_waste&action=edit&redlink=1http://en.wikipedia.org/wiki/Sawhttp://en.wikipedia.org/wiki/Ingothttp://en.wikipedia.org/wiki/UMG_Sihttp://en.wikipedia.org/wiki/Polysiliconhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-autogenerated1-18http://en.wikipedia.org/wiki/IMEChttp://en.wikipedia.org/wiki/IEEEhttp://en.wikipedia.org/wiki/IEEEhttp://en.wikipedia.org/wiki/PVShttp://en.wikipedia.org/wiki/PVShttp://en.wikipedia.org/wiki/BP_Solarhttp://en.wikipedia.org/wiki/Multicrystalline_siliconhttp://en.wikipedia.org/wiki/US_DOEhttp://en.wikipedia.org/wiki/Ribbon_siliconhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-17http://en.wikipedia.org/wiki/Moltenhttp://en.wikipedia.org/wiki/Multicrystallinehttp://en.wikipedia.org/w/index.php?title=Silicon_waste&action=edit&redlink=1http://en.wikipedia.org/wiki/Sawhttp://en.wikipedia.org/wiki/Ingothttp://en.wikipedia.org/wiki/UMG_Sihttp://en.wikipedia.org/wiki/Polysiliconhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-autogenerated1-18http://en.wikipedia.org/wiki/IMEChttp://en.wikipedia.org/wiki/IEEEhttp://en.wikipedia.org/wiki/IEEEhttp://en.wikipedia.org/wiki/PVShttp://en.wikipedia.org/wiki/BP_Solar


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with ".# mm wire. 3)0Ks roadmap6 presented at the organi7ationKs recent

annual research reiew meeting6 enisions use of "."A mm wafers by !"#>.

I!"J

T), ,$"

Main article: Thin film solar cell

Thin&film technologies reduce the amount of material re8uired in creating a

solar cell. Though this reduces material cost6 it may also reduce energy

conersion efficiency. Thin&film silicon cells hae become popular due to

cost6 fle'ibility6 lighter weight6 and ease of integration6 compared to wafer

silicon cells.

C%, *'$$r,' "#$%r &'$$

Main article: !admium telluride photovoltaics

* cadmium telluride solar cell use a cadmium tellurideG0dTeH thin film6 a

semiconductor layer to absorb and conert sunlight into electricity.

$olarbu77I!#J has reported that the lowest 8uoted thin&film module price

stands at 2$#.@? per watt&peak6 with the lowest crystalline silicon Gc&$iH

module at !.


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Main article: !opper indium gallium selenide solar cell

0opper indium gallium selenideG031$H is a direct&bandgapmaterial. 3t has

the highest efficiency GV!"OH among thin film materials Gsee 031$ solar

cellsH. Traditional methods of fabrication inole acuum processes

including co&eaporation and sputtering. Recent deelopments at 3DandNanosolar hae been targeting to lower the cost by using non&acuum

solution processes.

G%$$, %r"',' $*,7&*,#

Main article:Multi"unction photovoltaic cell

(igh&efficiency multijunction cells were originally deeloped for special

applications such as satellitesand space e'ploration6 but at present6 their use

in terrestrial concentrators might be the lowest cost alternatie in terms of

Fk9h and F9.I!;JThese multijunction cells consist of multiple thin films

produced using metalorganic apour phase epita'y. * triple&junction cell6 for

e'ample6 may consist of the semiconductors 1a*s6 1e6 and 1a3nP!.I!
http://en.wikipedia.org/wiki/Copper_indium_gallium_selenide_solar_cellhttp://en.wikipedia.org/wiki/Copper_indium_gallium_selenidehttp://en.wikipedia.org/wiki/Direct_bandgaphttp://en.wikipedia.org/wiki/Copper_Indium_Gallium_Selenide_Solar_Cellshttp://en.wikipedia.org/wiki/Copper_Indium_Gallium_Selenide_Solar_Cellshttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Nanosolarhttp://en.wikipedia.org/wiki/Multijunction_photovoltaic_cellhttp://en.wikipedia.org/wiki/Satellitehttp://en.wikipedia.org/wiki/Space_explorationhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-22http://en.wikipedia.org/wiki/Metalorganic_vapour_phase_epitaxyhttp://en.wikipedia.org/wiki/Gallium(III)_arsenidehttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Indium_gallium_phosphidehttp://en.wikipedia.org/wiki/Indium_gallium_phosphidehttp://en.wikipedia.org/wiki/Solar_cell#cite_note-23http://en.wikipedia.org/wiki/Band_gaphttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-24http://en.wikipedia.org/wiki/Copper_indium_gallium_selenide_solar_cellhttp://en.wikipedia.org/wiki/Copper_indium_gallium_selenidehttp://en.wikipedia.org/wiki/Direct_bandgaphttp://en.wikipedia.org/wiki/Copper_Indium_Gallium_Selenide_Solar_Cellshttp://en.wikipedia.org/wiki/Copper_Indium_Gallium_Selenide_Solar_Cellshttp://en.wikipedia.org/wiki/IBMhttp://en.wikipedia.org/wiki/Nanosolarhttp://en.wikipedia.org/wiki/Multijunction_photovoltaic_cellhttp://en.wikipedia.org/wiki/Satellitehttp://en.wikipedia.org/wiki/Space_explorationhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-22http://en.wikipedia.org/wiki/Metalorganic_vapour_phase_epitaxyhttp://en.wikipedia.org/wiki/Gallium(III)_arsenidehttp://en.wikipedia.org/wiki/Germaniumhttp://en.wikipedia.org/wiki/Indium_gallium_phosphidehttp://en.wikipedia.org/wiki/Solar_cell#cite_note-23http://en.wikipedia.org/wiki/Band_gaphttp://en.wikipedia.org/wiki/Electromagnetic_radiationhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-24


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This technology is currently being utili7ed in the ars )'ploration Roer

missions which hae run far past their C" day design life.

Tandem solar cells based on monolithic6 series connected6 gallium indium

phosphide G1a3nPH6 gallium arsenide 1a*s6 and germanium 1e pn junctions6

are seeing demand rapidly rise. 3n just the past #! months G#!F!""? E#!F!""@H6 the cost of " per kg to

?A" per kg. *dditionally6 germanium metal prices hae risen substantially

to #"""E#!"" per kg this year. Those materials include gallium G


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state cell designs. +$$0Ks can be engineered into fle'ible sheets6 and

although its conersion efficiency is less than the best thin film cells6 its

priceFperformance ratioshould be high enough to allow them to compete

with fossil fuel electrical generation. The +$$0 has been deeloped by Prof.

ichael 1rXt7elin #CC# at the $wiss -ederal 3nstitute of TechnologyG)P-4H

in 4ausanne G0(H.

Typically a ruthenium metalorganic dye GRu&centeredH is used as a

monolayerof light&absorbing material. The dye&sensiti7ed solar cell depends

on a mesoporouslayer of nanoparticulatetitanium dio'ideto greatly amplify

the surface area G!""E;"" m!Fg Ti,!6 as compared to appro'imately #" m!Fg

of flat single crystalH. The photogenerated electrons from the light absorbing

dye are passed on to the n-type Ti,!6 and the holes are absorbed by an

electrolyteon the other side of the dye. The circuit is completed by a redo'

couple in the electrolyte6 which can be li8uid or solid. This type of cell

allows a more fle'ible use of materials6 and is typically manufactured by

screen printingandFor use of 2ltrasonic No77les6 with the potential for lower

processing costs than those used for bulksolar cells. (oweer6 the dyes in

these cells also suffer from degradationunder heat and 2%light6 and the cell

casing is difficult to sealdue to the solents used in assembly. 3n spite of the

aboe6 this is a popular emerging technology with some commercial impact

forecast within this decade. The first commercial shipment of +$$0 solar

modules occurred in /uly !""C from 1!


38/56

of a simple roll&to&roll printing process6 leading to ine'pensie6 large scale

production.

,rganic solar cells and polymer solar cells are built from thin films

Gtypically #"" nmH of organic semiconductorsincluding polymers6 such as

polyphenylene inylene and small&molecule compounds like copperphthalocyanine Ga blue or green organic pigmentH and carbon fullerenesand

fullerene deriaties such as P0D. )nergy conersion efficiencies

achieed to date using conductie polymers are low compared to inorganic

materials. (oweer6 it improed 8uickly in the last few years and the highest

NR)4 GNational Renewable )nergy 4aboratoryH certified efficiency has

reached ?.@@O.I!@J 3n addition6 these cells could be beneficial for some

applications where mechanical fle'ibility and disposability are important.

These deices differ from inorganic semiconductor solar cells in that they do

not rely on the large built&in electric field of a PN junction to separate the

electrons and holes created when photons are absorbed. The actie region of

an organic deice consists of two materials6 one which acts as an electron

donor and the other as an acceptor. 9hen a photon is conerted into an

electron hole pair6 typically in the donor material6 the charges tend to remain

bound in the form of an e'citon6 and are separated when the e'citon diffuses

to the donor&acceptor interface. The short e'citon diffusion lengths of most

polymer systems tend to limit the efficiency of such deices. Nanostructured

interfaces6 sometimes in the form of bulk heterojunctions6 can improe

performance.I!AJ

S,$, *), ,$"
http://en.wikipedia.org/wiki/Polymer_solar_cellhttp://en.wikipedia.org/wiki/Organic_semiconductorhttp://en.wikipedia.org/wiki/Polyphenylene_vinylenehttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/PCBMhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-26http://en.wikipedia.org/wiki/Excitonhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-27http://en.wikipedia.org/wiki/Polymer_solar_cellhttp://en.wikipedia.org/wiki/Organic_semiconductorhttp://en.wikipedia.org/wiki/Polyphenylene_vinylenehttp://en.wikipedia.org/wiki/Fullerenehttp://en.wikipedia.org/wiki/PCBMhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-26http://en.wikipedia.org/wiki/Excitonhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-27


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$ilicon thin&film cells are mainly deposited by chemical apor deposition

Gtypically plasma&enhanced GP)&0%+HH from silanegas and hydrogen gas.

+epending on the deposition parameters6 this can yieldI!CJ

#. *morphous siliconGa&$i or a&$i(H

!. Protocrystallinesilicon or;. Nanocrystalline siliconGnc&$i or nc&$i(H6 also called microcrystalline

silicon.

3t has been found that protocrystalline silicon with a low olume fraction of

nanocrystalline silicon is optimal for high open circuit oltage. I;"J These

types of silicon present dangling and twisted bonds6 which results in deep

defects Genergy leels in the bandgapH as well as deformation of the alence

and conduction bands Gband tailsH. The solar cells made from these materials

tend to hae lower energy conversion efficiency than bulksilicon6 but are

also less e'pensie to produce. The 8uantum efficiencyof thin film solar

cells is also lower due to reduced number of collected charge carriers per

incident photon.

*n amorphous silicon Ga&$iH solar cell is made of amorphous or

microcrystalline silicon and its basic electronic structure is the p&i&n

junction. *s the amorphous structure has a higher absorption rate of light

than crystalline cells6 the complete light spectrum can be absorbed with a

ery thin layer of photo&electrically actie material. * film only # micron

thick can absorb C"O of the usable solar energy.I;#JThe production of a&$i

thin film solar cells uses glass as a substrate and deposits a ery thin layer ofsilicon by plasma&enhanced chemical apor deposition GP)0%+H. *&$i

manufacturers are working towards lower costs per watt and higher

conersion efficiency with continuous research and deelopment on

ultijunction solar cells for solar panels. *nwell Technologies 4imited
http://en.wikipedia.org/wiki/Silicon_thin-film_cellhttp://en.wikipedia.org/wiki/Chemical_vapor_depositionhttp://en.wikipedia.org/wiki/Silanehttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-28http://en.wikipedia.org/wiki/Amorphous_siliconhttp://en.wikipedia.org/wiki/Protocrystallinehttp://en.wikipedia.org/wiki/Nanocrystalline_siliconhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-29http://en.wikipedia.org/wiki/Quantum_efficiencyhttp://en.wikipedia.org/wiki/Amorphous_siliconhttp://en.wikipedia.org/wiki/P-i-n_and_n-i-phttp://en.wikipedia.org/wiki/Solar_cell#cite_note-30http://en.wikipedia.org/wiki/Plasma-enhanced_chemical_vapor_depositionhttp://en.wikipedia.org/wiki/Multijunction_solar_cellhttp://en.wikipedia.org/wiki/Anwell_Technologies_Limitedhttp://en.wikipedia.org/wiki/Silicon_thin-film_cellhttp://en.wikipedia.org/wiki/Chemical_vapor_depositionhttp://en.wikipedia.org/wiki/Silanehttp://en.wikipedia.org/wiki/Hydrogenhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-28http://en.wikipedia.org/wiki/Amorphous_siliconhttp://en.wikipedia.org/wiki/Protocrystallinehttp://en.wikipedia.org/wiki/Nanocrystalline_siliconhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-29http://en.wikipedia.org/wiki/Quantum_efficiencyhttp://en.wikipedia.org/wiki/Amorphous_siliconhttp://en.wikipedia.org/wiki/P-i-n_and_n-i-phttp://en.wikipedia.org/wiki/Solar_cell#cite_note-30http://en.wikipedia.org/wiki/Plasma-enhanced_chemical_vapor_depositionhttp://en.wikipedia.org/wiki/Multijunction_solar_cellhttp://en.wikipedia.org/wiki/Anwell_Technologies_Limited


40/56

recently announced its target for multi&substrate&multi&chamber P)0%+6 to

lower the cost to 2$+".> per watt.I;!J

*morphous silicon has a higher bandgap G#.@ e%H than crystalline silicon Gc&

$iH G#.# e%H6 which means it absorbs the isible part of the solar spectrum

more strongly than the infraredportion of the spectrum. *s &-S,has aboutthe same bandgap as c&$i6 the nc&$i and a&$i can adantageously be

combined in thin layers6 creating a layered cell called a *%' &'$$. The top

cell in a&$i absorbs the isible light and leaes the infrared part of the

spectrum for the bottom cell in nc&$i.

Recently6 solutions to oercome the limitations of thin&film crystalline

silicon hae been deeloped. 4ight trapping schemes where the weakly

absorbed long waelength light is obli8uely coupled into the silicon and

traerses the film seeral times can significantly enhance the absorption of

sunlight in the thin silicon films.I;;J Thermal processing techni8ues can

significantly enhance the crystal 8uality of the silicon and thereby lead to

higher efficiencies of the final solar cells.I;


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Poly&crystalline silicon wafers are made by wire&sawing block&cast silicon

ingots into ery thin G#A" to ;>" micrometerH slices or wafers. The wafers

are usually lightly p&typedoped. To make a solar cell from the wafer6 a

surface diffusion of n&typedopants is performed on the front side of the

wafer. This forms a p&n junction a few hundred nanometers below the

surface.

*ntireflection coatings6 to increase the amount of light coupled into the solar

cell6 are typically ne't applied. $ilicon nitride has gradually replaced

titanium dio'ide as the antireflection coating because of its e'cellent surface

passiation 8ualities. 3t preents carrier recombination at the surface of the

solar cell. 3t is typically applied in a layer seeral hundred nanometers thick

using plasma&enhanced chemical apor deposition GP)0%+H. $ome solar

cells hae te'tured front surfaces that6 like antireflection coatings6 sere to

increase the amount of light coupled into the cell. $uch surfaces can usually

only be formed on single&crystal silicon6 though in recent years methods of

forming them on multicrystalline silicon hae been deeloped.

The wafer then has a full area metal contact made on the back surface6 and a

grid&like metal contact made up of fine LfingersL and larger LbusbarsL are

screen&printed onto the front surface using a silerpaste. The rear contact is

also formed by screen&printing a metal paste6 typically aluminium. 2sually

this contact coers the entire rear side of the cell6 though in some cell

designs it is printed in a grid pattern. The paste is then fired at seeral

hundred degrees celsius to form metal electrodes in ohmic contactwith the

silicon. $ome companies use an additional electro&plating step to increase

the cell efficiency. *fter the metal contacts are made6 the solar cells are

interconnected in series GandFor parallelH by flat wires or metal ribbons6 and
http://en.wikipedia.org/wiki/P-type_semiconductorhttp://en.wikipedia.org/wiki/N-type_semiconductorhttp://en.wikipedia.org/wiki/Silverhttp://en.wikipedia.org/wiki/Ohmic_contacthttp://en.wikipedia.org/wiki/P-type_semiconductorhttp://en.wikipedia.org/wiki/N-type_semiconductorhttp://en.wikipedia.org/wiki/Silverhttp://en.wikipedia.org/wiki/Ohmic_contact


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assembled into modules or Lsolar panelsL. $olar panels hae a sheet of

tempered glasson the front6 and apolymerencapsulation on the back.

L,'"(%

ost commercially aailable solar cells are capable of producing electricity

for at least twenty years without a significant decrease in efficiency. The

typical warranty gien by panel manufacturers is for a period of !> E ;"

years6 wherein the output shall not fall below a specified percentage Garound

A"OH of the rated capacity.I;>J
http://en.wikipedia.org/wiki/Photovoltaic_modulehttp://en.wikipedia.org/wiki/Tempered_glasshttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-34http://en.wikipedia.org/wiki/Solar_cell#cite_note-34http://en.wikipedia.org/wiki/Photovoltaic_modulehttp://en.wikipedia.org/wiki/Tempered_glasshttp://en.wikipedia.org/wiki/Polymerhttp://en.wikipedia.org/wiki/Solar_cell#cite_note-34


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COOLINGMECH NISM


44/56

COOLING MECH NISM

9heneer the moisture is e'posed air either in the form of droplets

GorH sheet6 part of it is eaporated. *s the li8uid changes into apour6 the

heat re8uired for eaporation is taken from the remaining water itself and

thus the water gets cooled.

9heneer the hot water comes in contact with the cold air6 the heat

from the water to air is also transferred as sensible heat as the hot water

temperature is higher than the cold air temperature. The heat transfer due to

eaporation increases6 as 9DT of atmosphere air is lower than +DT of air.

The difference between the +DT and 9DT indicates the capacity of air to

absorbs the water apor. The rate of heat transfer between the hot water and

air depends upon

#. The initial temperature of hot water

!. Temperature of atmospheric air6

;. Relatie humidity of air6


45/56

>. (igher +DT

?. 4ower 9DT

@. (igher air moement gies the better cooling of water

A. *rea of heat transfer

C. +uration of contact between the two medicines

The net heat absorbed per kg of air from the hot water is gien by

A"O of total heat lost by water is remoed by eaporation and !"O by

sensible heat transfer.

Total heat transferred Y heat of eaporation Z sensible heat

The rate of eaporation of water in cooling tower and subse8uent

reduction in water temperature depends upon the following factors6

*mount of water surface e'posed

The time of e'posure

The relatie elocity of air passing oer the water droplets formed in

0ooling tower

The R.(. of air and difference between the inlet air 9DT and water

3nlet temperature

The direction of air flow relatie to water

(igher the surface area6 more time of e'posure6 low relatie humidity6

higher difference between 9DT of air and water inlet temperature and cross

flow lead to effectie cooling and reduce the tower si7e.


46/56

The temperature difference between 9DT of incoming air and

outgoing temperature of circulating water is known as 0ooling tower

approach lower cooling tower approach is always desirable as it is an

indication of effectie cooling. (igher the 8uantity of water circulated is

economically also limited by the power re8uirements of the 09 pump.

* cooling tower is a semi&closed deice for eaporating cooling of

water by contact with air. 3t is a wooden6 steel or concrete structure and

corrugated surfaces GorH through or baffle or perforated trays are proided

inside the tower for uniform distribution and better atomi7ation of water in

the tower. The hot water coming out from the condenser is fed to the tower

on the top and allowed to tickle down in the form of thin sheet GorH drop. The

airflow form the bottom of the tower of the tower and perpendicular to the

direction of flow and than e'haust to the atmosphere after effectie cooling.

To preent the escape of water particles with air6 drift eliminators are

proided at the top of the tower.


47/56

F

DV NT GES &

DIS DV NT GES


48/56

DV NT GES

$maller in si7e

The cooling capacity can be controlled in amount of forced air

0an be located inside the building because they do not depend upon

the atmospheric air.

DIS DV NT GES

(igh 3nitial cost

The maintenance of fans6 motors and controls increases the operating

cost


49/56

COST ESTIM TION


50/56

COST ESTIM TION

#. Dlower # #""".""

!. $olar panel # !""".""

;. esh < #"".""

. %ales ! #"".""

?. pump # A"".""

@. Paints && !"".""

A. fabrication of cooler # #?"".""

&&&&&&&&&&&

T,T*4 ?""".""

&&&&&&&&&&&&&&


51/56

CONCLUSION


52/56

CONCLUSION

The test carried out on cooling tower indicates that the apparatus has

gien correct alues comparable to apparatus manufactured by professionals

This apparatus can be easily manufactured and marketed

0ost of this apparatus is reasonable

The e'perience gained in this project will gie self E confidence to

design simple machines and apparatus on similar lines under entrepreneurs

scheme of the 1oernment.


53/56

BIBLIOGR PHY


54/56

BIBILOGR PHY

#. *ir conditioning by R.$. =2R3

!. Production technology by (ajra 0houdry

;. achine shop technology by $.$.*N3*N

.*PP43)+ T()R,+:N*30$ D: $2N+R*,,RT(:


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PHOTOVIEW


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PHOTOVIEW

Documents

Air Cooler Solar 2011 Sa Poly Final