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SOLAR ENERGYSOLAR ENERGY
Thiagarajar College of EngineeringThiagarajar College of Engineering
Madurai – 625 015.Madurai – 625 015.
INTRODUCTION TOINTRODUCTION TO
SOLAR ENERGYSOLAR ENERGY
An overview ofAn overview of
the technologiesthe technologies
and applicationsand applications
ON JULY 4, 1997, THE PATHFINDERON JULY 4, 1997, THE PATHFINDER
SPACECRAFT BOUNCED TO A STOP ON MARS.SPACECRAFT BOUNCED TO A STOP ON MARS.
THE NEXT DAY, THE ROVER SOJOURNERTHE NEXT DAY, THE ROVER SOJOURNER
ROLLED OUT OF ONE OF THE LANDER PETALSROLLED OUT OF ONE OF THE LANDER PETALS
ONTO THE SURFACE OF THE PLANET TOONTO THE SURFACE OF THE PLANET TO
BEGIN ITS MISSION OF EXPLORATION.BEGIN ITS MISSION OF EXPLORATION.
Sojourner was able to move around the planet and
examine rocks like this one named “Yogi” – located
20 feet from the Pathfinder lander – thanks to
the power generated by the solar panel on its
WHAT DO YOU SEE HERE?WHAT DO YOU SEE HERE?
Take a close look –Take a close look –
is this the profile of ais this the profile of a
beautiful young lady, or thebeautiful young lady, or the
face of an ugly, old woman?face of an ugly, old woman?
They’re both here, butThey’re both here, but
for a variety of reasonsfor a variety of reasons
that make up your ownthat make up your own
psychological make-up,psychological make-up,
some of you see onesome of you see one
woman, some the other.woman, some the other.
When people think of solar energy,When people think of solar energy,
the same thing often happens.the same thing often happens.
Some see it as something for theSome see it as something for the
future, others see it as somethingfuture, others see it as something
that is here today.that is here today.
IF YOU THINK SOLAR ENERGY ISIF YOU THINK SOLAR ENERGY IS
SOMETHING TO BE USED IN THE FUTURE .SOMETHING TO BE USED IN THE FUTURE .
. .. .
• you may be picturingyou may be picturing
something like this solarsomething like this solar
array used by the spacearray used by the space
shuttle to provide for powershuttle to provide for power
needs in outer space.needs in outer space.
• There are people who thinkThere are people who think
that solar energy isthat solar energy is
something not quite down-something not quite down-
to-earth and not ready to useto-earth and not ready to use
HOWEVER, THERE ARE OTHER PEOPLEHOWEVER, THERE ARE OTHER PEOPLE
WHO THINK OF SOLAR ENERGY ASWHO THINK OF SOLAR ENERGY AS
SOMETHING THAT’S BEEN AROUND FOR ASOMETHING THAT’S BEEN AROUND FOR A
LONG TIME.LONG TIME.
Solar collector for
A home in California in 1906
For hundreds of years, people have wanted to harness
the sun’s power for weapons, heating, and many other
uses to make their lives more comfortable.
• Actually, the first solar waterActually, the first solar water
heating collector appears to haveheating collector appears to have
been built in the 18been built in the 18thth
Century by aCentury by a
Swiss scientistSwiss scientist
• who constructed a simplewho constructed a simple
wooden box with a glass top andwooden box with a glass top and
a black base.a black base.
• It trapped solar energy, and theIt trapped solar energy, and the
collector reached a temperature ofcollector reached a temperature of
190 degrees Fahrenheit.190 degrees Fahrenheit.
SO WHICH VIEW OF SOLAR ENERGYSO WHICH VIEW OF SOLAR ENERGY
-- FOR THE FUTURE OR FOR TODAY-- FOR THE FUTURE OR FOR TODAY
– IS CORRECT?– IS CORRECT?
• Probably a little of both.Probably a little of both.
• Solar energy will certainly play anSolar energy will certainly play an
important role in the future energy needsimportant role in the future energy needs
of our planetof our planet
• But it’s also here today and ready forBut it’s also here today and ready for
hundreds of uses in homes, businesses,hundreds of uses in homes, businesses,
and industry.and industry.
THE SUN IS AN INEXHAUSTIBLE POWERTHE SUN IS AN INEXHAUSTIBLE POWER
SUPPLY. IT BRINGS ENOUGH ENERGY TOSUPPLY. IT BRINGS ENOUGH ENERGY TO
OUR PLANET EVERY SINGLE DAY TO MEETOUR PLANET EVERY SINGLE DAY TO MEET
A FULL YEAR’S WORTH OF ENERGY FORA FULL YEAR’S WORTH OF ENERGY FOR
EVERYONE ON EARTH.EVERYONE ON EARTH.
• And during the past century – back toAnd during the past century – back to
1891, in fact, when the first solar1891, in fact, when the first solar
collector was manufactured in thecollector was manufactured in the
United States, U.S. industry hasUnited States, U.S. industry has
developed a variety of products thatdeveloped a variety of products that
have proven both reliable and cost-have proven both reliable and cost-
effective in meeting all kinds of energyeffective in meeting all kinds of energy
THE BATTERIES IN THIS SOLAR-POWERED LIGHT IN ATHE BATTERIES IN THIS SOLAR-POWERED LIGHT IN A
REMOTE PART OF KEY WEST, FLORIDA, ARE CHARGED BYREMOTE PART OF KEY WEST, FLORIDA, ARE CHARGED BY
THE SUN DURING THE DAY TO PROVIDE POWER FORTHE SUN DURING THE DAY TO PROVIDE POWER FOR
STREET LIGHTING AT NIGHT.STREET LIGHTING AT NIGHT.
• But to many people, solarBut to many people, solar
power today means justpower today means just
• Calculators watches andCalculators watches and
other simple homeother simple home
products like this lanternproducts like this lantern
that use solar powerthat use solar power
instead of electricity toinstead of electricity to
charge the batteries.charge the batteries.
They don’t realize that millions ofThey don’t realize that millions of
people around the world use solarpeople around the world use solar
energy because it is the only available,energy because it is the only available,
reliable power source for many of theirreliable power source for many of their
basic needs such as lighting and waterbasic needs such as lighting and water
Meanwhile, do-it-yourselfers haveMeanwhile, do-it-yourselfers have
long tried to build their own solarlong tried to build their own solar
systems to take advantage of thesystems to take advantage of the
free power provided by thefree power provided by the
sun . . .sun . . .
THE OWNER OF A SMALL LAUNDRY IN NORTHERNTHE OWNER OF A SMALL LAUNDRY IN NORTHERN
FLORIDA TRIED TO BUILD HIS OWN CONCENTRATINGFLORIDA TRIED TO BUILD HIS OWN CONCENTRATING
SYSTEM FOR WATER HEATING. (WE DON’T KNOW IF THESYSTEM FOR WATER HEATING. (WE DON’T KNOW IF THE
SIGN IN THE BACKGROUND WAS PUT UP BEFORE ORSIGN IN THE BACKGROUND WAS PUT UP BEFORE OR
AFTER THIS HOMEMADE SYSTEM WAS BUILT.)AFTER THIS HOMEMADE SYSTEM WAS BUILT.)
BUT WE DO KNOW THAT GROWING PUBLICBUT WE DO KNOW THAT GROWING PUBLIC
CONCERN ABOUT ENVIRONMENTALCONCERN ABOUT ENVIRONMENTAL
PROBLEMS . . .PROBLEMS . . .
MEANWHILE, THERE IS ONE ENERGY SOURCE THAT ISMEANWHILE, THERE IS ONE ENERGY SOURCE THAT IS
FREE AND INEXHAUSTIBLE. IT’S LIKE A GIANT NUCLEARFREE AND INEXHAUSTIBLE. IT’S LIKE A GIANT NUCLEAR
REACTOR – ONLY THIS ONE IS LOCATED 93 MILLIONREACTOR – ONLY THIS ONE IS LOCATED 93 MILLION
MILES AWAY.MILES AWAY.
• It’s not uncommon aroundIt’s not uncommon around
the world to see solarthe world to see solar
systems used along withsystems used along with
the traditional ways of lifethe traditional ways of life
to become an integralto become an integral
part of people’s lives.part of people’s lives.
THE HOUSE OF THE FUTURE?THE HOUSE OF THE FUTURE?
• This zero-energyThis zero-energy
house in thehouse in the
Netherlands hasNetherlands has
of PV panelsof PV panels
for powerfor power
generation andgeneration and
of solarof solar
collectors for watercollectors for water
and space heating.and space heating.
NO MATTER WHAT THE FUTURE WILL BE LIKE, ONENO MATTER WHAT THE FUTURE WILL BE LIKE, ONE
THING IS FOR CERTAIN: SOME TYPE OF ENERGYTHING IS FOR CERTAIN: SOME TYPE OF ENERGY
WILL BE NEEDED TO POWER IT.WILL BE NEEDED TO POWER IT.
What will that energy source be?
The answer ought to be obvious.
It’s been up there all the time.
EARTH’S RADIATIONEARTH’S RADIATION
AND THE SEASONSAND THE SEASONS
Need to KnowNeed to Know
Energy flow through the atmosphereEnergy flow through the atmosphere
Energy changes with latitude and seasonEnergy changes with latitude and season
What is the incoming and outgoing radiation?
γ-rays X-rays UV Infrared Microwave Radio
10-8 0.01 0.4-0.7 103
Peak energy output of sun
output at ~20o
Wavelength in micro-metres (microns or µm)
10,000 times more
energy than we use
24% absorbed in atmosphere
INCOMING SOLAR RADIATIONINCOMING SOLAR RADIATION
• Top of atmosphere, solar constant 1.37kW/mTop of atmosphere, solar constant 1.37kW/m22
J/year (humans use ~4x10J/year (humans use ~4x102020
• Full sun at surface, facing sun, ~1kW/mFull sun at surface, facing sun, ~1kW/m22
• But due to clouds, absorption, scattering only about 25% ofBut due to clouds, absorption, scattering only about 25% of
sunlight, on average, reaches surfacesunlight, on average, reaches surface
• At one location only daylight ½ the timeAt one location only daylight ½ the time
From Christopherson p89
Some trivia: Australians each use about
250GJ fossil fuel per year, = about 6m2
All the energy
absorbed by the
air and surface is
out into space
OUTGOING RADIATIONOUTGOING RADIATION
• Infrared with a peak intensity at about 10Infrared with a peak intensity at about 10µµmm
• Gases such as COGases such as CO22 absorb some of this infrared radiation,absorb some of this infrared radiation,
hence concern about global warminghence concern about global warming
• Cloudy night is warmer because radiation cannot ‘escape’Cloudy night is warmer because radiation cannot ‘escape’
to spaceto space
THE SEASONSTHE SEASONS
• Solar SystemSolar System
• Earth about 150,000km from sunEarth about 150,000km from sun
Summer and Winter Sun Paths for Hobart
Very important for solar house design
• Radiation from sunRadiation from sun
• Radiation from EarthRadiation from Earth
• More incoming energy near equatorMore incoming energy near equator
• Earth’s tilt:- seasonsEarth’s tilt:- seasons
Associate Professor – EEE Dept.Associate Professor – EEE Dept.
Thiagarajar College of EngineeringThiagarajar College of Engineering
Madurai – 625 015.Madurai – 625 015.
Most of Energy, Earth Receive from
Sun Comes in the Form of Light
FLAT PLATE SOLAR COLLECTORFLAT PLATE SOLAR COLLECTOR
SOLAR ENERGY -SOLAR ENERGY -
INTRODUCTIONINTRODUCTION• Solar – The Greatest potential of the renewable energy sourcesSolar – The Greatest potential of the renewable energy sources
• Solar power hitsSolar power hits
• Atmosphere – 10Atmosphere – 101717
• Earth Surface – 10Earth Surface – 101616
• Total world Power Demand – 10Total world Power Demand – 101313
• 1000 times the power requirement of world1000 times the power requirement of world
• 5% utilization will meet 50 times the requirement5% utilization will meet 50 times the requirement
• Energy Radiated by bright sun is – 1kw/mEnergy Radiated by bright sun is – 1kw/m22
SOLAR POWERSOLAR POWER
• Solar thermal technologiesSolar thermal technologies
• Concentrating solar power systemConcentrating solar power system
• Flat plate solar collectorsFlat plate solar collectors
• Passive solar heating designPassive solar heating design
• Utilize the sun photons orUtilize the sun photons or
light to create electricity.light to create electricity.
Passive solar (e.g. skylight)
Active solar (solar hot water)
Integration of solar energy systems in buildings
ACTIVE SOLARACTIVE SOLAR
• Also called ‘solar thermal’Also called ‘solar thermal’
• Common applicationsCommon applications
• solar hot water (domestic or non-domestic)solar hot water (domestic or non-domestic)
• swimming pool heatingswimming pool heating
• space heating or air preheatingspace heating or air preheating
• solar air-conditioningsolar air-conditioning
• using absorption or desiccant cooling systemusing absorption or desiccant cooling system
• electricity generationelectricity generation
• using steam plant and concentratorusing steam plant and concentrator
SOLAR COLLECTORSSOLAR COLLECTORS
• A device for collecting solar radiation &A device for collecting solar radiation &
transfer the energy to a fluid passing thro’transfer the energy to a fluid passing thro’
• Types of Solar CollectorsTypes of Solar Collectors
• Flat plateFlat plate
• Concentrating collectors are preferred forConcentrating collectors are preferred for
increasing the intensity of solar radiationincreasing the intensity of solar radiation
ADVANTAGES OF FLAT PLATEADVANTAGES OF FLAT PLATE
• Using Direct & diffused solar radiationUsing Direct & diffused solar radiation
• Not require any orientation controlNot require any orientation control
system towards sunsystem towards sun
• Rugged & require Little maintenanceRugged & require Little maintenance
• Simpler constructionSimpler construction
MAIN COMPONENTS OF FLATMAIN COMPONENTS OF FLAT
PLATE COLLECTORSPLATE COLLECTORS
• A Transparent coverA Transparent cover
• One or More Sheets of glass / Plastic film / SheetOne or More Sheets of glass / Plastic film / Sheet
• Tubes / Fins / Passages or ChannelsTubes / Fins / Passages or Channels
• Integral part of collectors absorber plateIntegral part of collectors absorber plate
• Absorber PlateAbsorber Plate
• Metallic one with Black surfaceMetallic one with Black surface
• Usually provided at the back side of collectors to minimizeUsually provided at the back side of collectors to minimize
the heat lossesthe heat losses
• Casing or ContainerCasing or Container
• Which enclose the above assemblyWhich enclose the above assembly
GLAZED FLAT PLATE SOLARGLAZED FLAT PLATE SOLAR
• Moderate costModerate cost
• Can operate atCan operate at
mains watermains water
• Heavier and moreHeavier and more
Basic structure of a flat-plate solar collector
Heat transfer processes at a flat-plate solar collector
EVACUATED TUBE COLLECTORSEVACUATED TUBE COLLECTORS
• Higher costHigher cost
• No convection lossesNo convection losses
• High temperatureHigh temperature
• Cold climatesCold climates
can be morecan be more
• Snow is less ofSnow is less of
a problema problem
Photo Credit: NRCan
Photo Credit: Nautilus
COLLECTOR CHOICECOLLECTOR CHOICE
• Flat plate collectors were selected overFlat plate collectors were selected over
evacuated tube collectors (ETC) forevacuated tube collectors (ETC) for
several reasons:several reasons:
• Simple construction reduces costSimple construction reduces cost
• Some ETC use two heat exchangersSome ETC use two heat exchangers
• Flat plate collectors with a selectiveFlat plate collectors with a selective
coating have out performed ETC undercoating have out performed ETC under
identical conditions in two separateidentical conditions in two separate
independent testsindependent tests
LIMITATIONS OF FLAT PLATELIMITATIONS OF FLAT PLATE
• Applicable, where temp. requirement is below 90Applicable, where temp. requirement is below 90ºCºC
• Space requirement is large compared to concentrated collectorsSpace requirement is large compared to concentrated collectors
• Partially effective during cloudy daysPartially effective during cloudy days
• Few applications requires Heat Transfer fluidsFew applications requires Heat Transfer fluids
• Non-freezing aqueous solutions required in cold countriesNon-freezing aqueous solutions required in cold countries
INTRODUCTION –INTRODUCTION –
CONCENTRATING COLLECTORSCONCENTRATING COLLECTORS
• To collect solar energy with high intensityTo collect solar energy with high intensity
• From solar radiation on the high energyFrom solar radiation on the high energy
absorbing surfaceabsorbing surface
• Have a Reflecting surface between solarHave a Reflecting surface between solar
radiations and the absorberradiations and the absorber
• Fluids can be heated up to 500Fluids can be heated up to 500ºC or moreºC or more
• Only direct solar radiation is mainly usedOnly direct solar radiation is mainly used
OPTICAL EFFICIENCYOPTICAL EFFICIENCY
• Reflection & Absorption Losses in theReflection & Absorption Losses in the
• Losses due to geometrical imperfectionsLosses due to geometrical imperfections
in the optical systemin the optical system
• Accounting the Combined effect of allAccounting the Combined effect of all
losses is indicated through a term calledlosses is indicated through a term called
Optical EfficiencyOptical Efficiency
LINE FOCUSING COLLECTORSLINE FOCUSING COLLECTORS
• Parabolic trough ReflectorParabolic trough Reflector
• Solar Radiation coming from the particular direction is collectedSolar Radiation coming from the particular direction is collected
• Over the area of the reflecting surfaceOver the area of the reflecting surface
• Concentrated at the focus of the parabolaConcentrated at the focus of the parabola
• Mostly cylindrical parabolic concentrators are usedMostly cylindrical parabolic concentrators are used
• Collector pipe, preferably with a selective absorber coatingCollector pipe, preferably with a selective absorber coating
• Used as absorberUsed as absorber
LINE FOCUSING COLLECTORLINE FOCUSING COLLECTOR
CONSTRUCTION OFCONSTRUCTION OF
PARABOLIC TROUGH REFLECTORPARABOLIC TROUGH REFLECTOR
• Dimension of parabolic cylindrical collector can beDimension of parabolic cylindrical collector can be
vary wide rangevary wide range
• Length of reflector is 3 to 5 MeterLength of reflector is 3 to 5 Meter
• Width about 1.5 to 2.4 MeterWidth about 1.5 to 2.4 Meter
• Ten or more such units are connected end to end in aTen or more such units are connected end to end in a
row & Several rows may also be paralleledrow & Several rows may also be paralleled
• Reflectors are made of Highly polished aluminum ofReflectors are made of Highly polished aluminum of
silvered glass or of a thin film of aluminized plastic on asilvered glass or of a thin film of aluminized plastic on a
firm basefirm base
• Elevation of Sun is always changingElevation of Sun is always changing
• The Reflector / Collector pipe must be turn continuouslyThe Reflector / Collector pipe must be turn continuously
with the help of solar tracking systemwith the help of solar tracking system
A TYPICAL CYLINDRICALA TYPICAL CYLINDRICAL
PARABOLIC SYSTEMPARABOLIC SYSTEM
MIRROR-STRIP REFLECTORMIRROR-STRIP REFLECTOR
• A No. of Plane or Slightly curved (Concave) mirror strips areA No. of Plane or Slightly curved (Concave) mirror strips are
mounted on a flat basemounted on a flat base
• The angles of the individual mirrors areThe angles of the individual mirrors are
• Such that they reflect solar radiation from a specific direction on toSuch that they reflect solar radiation from a specific direction on to
the same focal linethe same focal line
• Angles of the mirrors can be adjusted to allow for changes in theAngles of the mirrors can be adjusted to allow for changes in the
sun elevationsun elevation
• While the focal line remains fixed positionWhile the focal line remains fixed position
• Alternatively Mirror strips may be fixed & Collector pipe movedAlternatively Mirror strips may be fixed & Collector pipe moved
• So as to remain on the focal lineSo as to remain on the focal line
MIRROR STRIP SOLARMIRROR STRIP SOLAR
ARRAY SOLAR DISH SHAPEDARRAY SOLAR DISH SHAPED
FRESNEL LENS COLLECTORFRESNEL LENS COLLECTOR
• In addition to the ReflectingIn addition to the Reflecting
collectors, a refraction collectorscollectors, a refraction collectors
has been developedhas been developed
• It utilizes the focusing effect of aIt utilizes the focusing effect of a
Fresnel lensFresnel lens
FLAT PLATE COLLECTOR WITHFLAT PLATE COLLECTOR WITH
ADJUSTABLE MIRRORSADJUSTABLE MIRRORS
• Consists of a Flat plate facing sunConsists of a Flat plate facing sun
• With mirrors attached to its North &With mirrors attached to its North &
South edgesSouth edges
• Mirrors are set at proper angleMirrors are set at proper angle
• Such that reflect solar radiation onSuch that reflect solar radiation on
the absorber platethe absorber plate
COMPOUND PARABOLICCOMPOUND PARABOLIC
•Consists of two facing parabolicConsists of two facing parabolic
mirrors on a plat plate collectormirrors on a plat plate collector
•Non focusing type collectorNon focusing type collector
•Called as Winston CollectorCalled as Winston Collector
ADVANTAGES OF CONCENTRATINGADVANTAGES OF CONCENTRATING
TYPE COLLECTORSTYPE COLLECTORS
• Surface area required per unit of SolarSurface area required per unit of Solar
Energy is lessEnergy is less
• Improves Collector EfficiencyImproves Collector Efficiency
• Solar Intensity is highSolar Intensity is high
• Less cost on insulation since collectorLess cost on insulation since collector
area is smallarea is small
• Heat loss is lessHeat loss is less
• Can be used for Electric PowerCan be used for Electric Power
• Anti-freeze requirement is less / nilAnti-freeze requirement is less / nil
• Only beam component is collectedOnly beam component is collected
• Solar tracking system requirementSolar tracking system requirement
• Additional maintenance requirementAdditional maintenance requirement
• For Dirt, Weather, OxidationFor Dirt, Weather, Oxidation
• Non-uniform flux on the absorberNon-uniform flux on the absorber
• Additional optical lossesAdditional optical losses
• High initial costHigh initial cost
SOLAR CELLSSOLAR CELLS
THE PHOTOVOLTAICTHE PHOTOVOLTAIC
Ryan SchlueterRyan Schlueter
WHAT ARE SOLAR CELLS?WHAT ARE SOLAR CELLS?
• Solar cells are devices that convert sunlight (solar energy) intoSolar cells are devices that convert sunlight (solar energy) into
• The most commonly utilized solar cell employs theThe most commonly utilized solar cell employs the
photovoltaic (PV) effect.photovoltaic (PV) effect.
• As sunlight falls on a bi-layer semi-conductive device, aAs sunlight falls on a bi-layer semi-conductive device, a
potential difference is created between the barriers.potential difference is created between the barriers.
• The voltage has the ability to produce a current in an externalThe voltage has the ability to produce a current in an external
circuit, thereby “making” useful electricity.circuit, thereby “making” useful electricity.
GENERATION OF THE SOLAR CELLGENERATION OF THE SOLAR CELL
• 1839: Henri Bequerel discovers that shining a light into1839: Henri Bequerel discovers that shining a light into
certain chemical solutions produces an electricalcertain chemical solutions produces an electrical
• 1877: the material metal selenium was used in might1877: the material metal selenium was used in might
meters. Very inefficient conductor.meters. Very inefficient conductor.
• 1954: Chapin, Pearson, and Fuller develop a solar cell1954: Chapin, Pearson, and Fuller develop a solar cell
with 6% efficiency.with 6% efficiency.
• Present: new materials have made it possible to reachPresent: new materials have made it possible to reach
about 18% efficiency. (Silicon)about 18% efficiency. (Silicon)
WHAT CAN SOLAR CELLS DO FORWHAT CAN SOLAR CELLS DO FOR
• Solar cells are a low maintenanceSolar cells are a low maintenance
source of electricity.source of electricity.
• They can be used in remote locations.They can be used in remote locations.
• Solar cells are reliable.Solar cells are reliable.
• Solar cells are non-polluting.Solar cells are non-polluting.
• Solar cells can produce small amountSolar cells can produce small amount
of energy for devices.of energy for devices.
• Solar cells run on a “renewable”Solar cells run on a “renewable”
source of energy. Reduce globalsource of energy. Reduce global
TYPES OF SOLAR CELLSTYPES OF SOLAR CELLS
(SILICON BASED)(SILICON BASED)
• Solar cells are made bySolar cells are made by
• Single crystal wafersSingle crystal wafers
• Poly-crystalline wafersPoly-crystalline wafers
• Thin-film technology.Thin-film technology.
• Single Wafer: sliced to theSingle Wafer: sliced to the
millimeter from a largemillimeter from a large
single crystal ingot.single crystal ingot.
• Very expensive, but theVery expensive, but the
silicon is much purer andsilicon is much purer and
therefore more efficient.therefore more efficient.
POLYCRYSTALLINE WAFERSPOLYCRYSTALLINE WAFERS
• Made by a casting processMade by a casting process
• In which molten silicon is poured into a mould.In which molten silicon is poured into a mould.
• It is allowed to set, and then cut into wafers.It is allowed to set, and then cut into wafers.
• Not as energy efficient.Not as energy efficient.
• About half the silicon is lost to dust in the cutting process.About half the silicon is lost to dust in the cutting process.
THIN-FILM TECHNOLOGYTHIN-FILM TECHNOLOGY
• Amorphous silicon made byAmorphous silicon made by
depositing silicon onto substratedepositing silicon onto substrate
from a reactive gas.from a reactive gas.
• Substrates are normally glass orSubstrates are normally glass or
• Thin film has ease of deposition, lowThin film has ease of deposition, low
cost, is mass produciblecost, is mass producible
• Suitable for large applications.Suitable for large applications.
THE DOPING PROCESSTHE DOPING PROCESS
• Adding an impurity to silicon in order to change its internal properties.Adding an impurity to silicon in order to change its internal properties.
• Because the production of energy depends on the separation ofBecause the production of energy depends on the separation of
positive and negative charges, silicon must be modified.positive and negative charges, silicon must be modified.
• The charge carrying behavior of the crystal silicon is changed.The charge carrying behavior of the crystal silicon is changed.
Silicon has 4 valence
electrons (electrons on
the outer shell). To create
an impurity between the
silicon bonds, boron and
phosphorus are added
through a heating/vapor
process.Silicon is very stable
in pure crystal form.
BORON’S JOBBORON’S JOB
• Boron has 3 valenceBoron has 3 valence
• When boron is introduced aWhen boron is introduced a
hole or electron vacancy ishole or electron vacancy is
• The hole is like a positiveThe hole is like a positive
charge because it attractscharge because it attracts
This type of silicon is called
P-type due to its positive
charge. Acceptor dopant.
PHOSPHORUS’ JOBPHOSPHORUS’ JOB
• Phosphorus has 5 valencePhosphorus has 5 valence
• Phosphorus adds an extraPhosphorus adds an extra
• The extra electron causesThe extra electron causes
a negative charge.a negative charge.
• This type of silicon isThis type of silicon is
called N-type due to itscalled N-type due to its
negative charge. Donornegative charge. Donor
dopant.dopant. 5 valence electrons
LET’S TALK SUNLIGHTLET’S TALK SUNLIGHT
• Light is composed of tiny packets of energy calledLight is composed of tiny packets of energy called
• Photons may have different masses and carry varyingPhotons may have different masses and carry varying
amounts of energy.amounts of energy.
• When a photon strikes an atom, it can interact with theWhen a photon strikes an atom, it can interact with the
electrons, and the photon’s energy can be absorbedelectrons, and the photon’s energy can be absorbed
• The additional energy can drive an atom’s outerThe additional energy can drive an atom’s outer
electrons off.electrons off.
• An electron freed in this manner is called aAn electron freed in this manner is called a
conduction electron because it is free to move about.conduction electron because it is free to move about.
• This is how sunlight stimulates an abundance ofThis is how sunlight stimulates an abundance of
electrons to be present on the N-type side of theelectrons to be present on the N-type side of the
SOLAR CELL MODELSOLAR CELL MODEL
• Here is a model of theHere is a model of the
typical solar cell.typical solar cell.
• Notice the split betweenNotice the split between
the two types of silicon.the two types of silicon.
COMBINING THE SILICON TYPESCOMBINING THE SILICON TYPES
• When the two types of silicon are put together a chargeWhen the two types of silicon are put together a charge
free zone is created between them, also known as thefree zone is created between them, also known as the
P-N junction.P-N junction.
• The charge free zone must be enlarged to maximize theThe charge free zone must be enlarged to maximize the
charge collection.charge collection.
• The electrons released by the sunlight flow more easilyThe electrons released by the sunlight flow more easily
in the region where there are many of them.in the region where there are many of them.
• The holes flow more easily in the P-type silicon.The holes flow more easily in the P-type silicon.
THE ELECTRIC FIELDDEALTHE ELECTRIC FIELDDEAL
• Every PV cell has an electric field.Every PV cell has an electric field.
• When the two types of silicon are joined, and sunlightWhen the two types of silicon are joined, and sunlight
hits them, all of the free electrons rush to fill in thehits them, all of the free electrons rush to fill in the
• But there are only so many holes.But there are only so many holes.
• A diode is made (electron “pusher”).A diode is made (electron “pusher”).
• After this electric field has been created, sunlightAfter this electric field has been created, sunlight
continues to hit the solar cells. The electric field willcontinues to hit the solar cells. The electric field will
cause the electrons to move to the n-side and thecause the electrons to move to the n-side and the
holes to move to the p-side creating a potentialholes to move to the p-side creating a potential
difference between the sides.difference between the sides.
PIECING IT TOGETHERPIECING IT TOGETHER
• A current is produced by the flow of electrons from the n-side.A current is produced by the flow of electrons from the n-side.
• If a wire is connected to the N-type silicon, and the other endIf a wire is connected to the N-type silicon, and the other end
attached to the P-type region, the electrons will flow through theattached to the P-type region, the electrons will flow through the
wire and be absorbed by the boron doped silicon, or P-type.wire and be absorbed by the boron doped silicon, or P-type.
This flow of electrons
through an external circuit
can be used just like
POWER OUTPUT AND EFFICIENCYPOWER OUTPUT AND EFFICIENCY
• Every photon only frees one electron.Every photon only frees one electron.
• Affected byAffected by
• Surface area of solar cellSurface area of solar cell
• Amount of sunlight hitting cellAmount of sunlight hitting cell
• Intensity of lightIntensity of light
• Cell material.Cell material.
• Mono-crystalline: 25% efficientMono-crystalline: 25% efficient
• Poly-crystalline: 20% efficientPoly-crystalline: 20% efficient
• Thin Film: 10% efficientThin Film: 10% efficient
PHOTOVOLTAIC PANELSPHOTOVOLTAIC PANELS
• Multiple solar cells working in coordination to provideMultiple solar cells working in coordination to provide
varying voltages.varying voltages.
• The cells are joined in series, or amorphous.The cells are joined in series, or amorphous.
• The number of cells directly affects the voltage.The number of cells directly affects the voltage.
Right: These panels are
beneficial to use for large
applications and greater
RELIABILITY OF SOLAR CELLSRELIABILITY OF SOLAR CELLS
• Most solar cells can be ensured to have a lifetime ofMost solar cells can be ensured to have a lifetime of
at least 25 years.at least 25 years.
• Solar cells are very durable.Solar cells are very durable.
Right: shows the
decreasing cost of
FUTURE PROSPECTSFUTURE PROSPECTS
• Solar cells have become a growing industry.Solar cells have become a growing industry.
• Demand for cells is increasing.Demand for cells is increasing.
• Solar cells reduce global warming.Solar cells reduce global warming.
• Much Japanese/Australian development.Much Japanese/Australian development.
OTHER APPLICATIONSOTHER APPLICATIONS
• Corrosion ProtectionCorrosion Protection
• Electric FencesElectric Fences
• Remote LightingRemote Lighting
• Solar powered waterSolar powered water
• Heated water treatment.Heated water treatment.
• Alivisatos, Paul. “Make and Use Solar Cells Efficiently.”Alivisatos, Paul. “Make and Use Solar Cells Efficiently.” Inside R & DInside R & D March 2002: 29.March 2002: 29. The Gale Group: InfoTrac OneFile.The Gale Group: InfoTrac OneFile.
Internet. 19 April 2002.Internet. 19 April 2002.
• Bond, Martin. “Solar Energy: Seeing the Light.”Bond, Martin. “Solar Energy: Seeing the Light.” GeographicalGeographical November 2000.November 2000. The Gale Group:The Gale Group:
InfoTrac OneFileInfoTrac OneFile. Internet. 19 April 2002.. Internet. 19 April 2002.
• Gorman, J. “New Method Lights a Path for Solar Cells.”Gorman, J. “New Method Lights a Path for Solar Cells.” Science NewsScience News August 2002: 11.August 2002: 11. The GaleThe Gale
Group: InfoTrac OneFileGroup: InfoTrac OneFile. Internet. 19 April 2002.. Internet. 19 April 2002.
• Green, Martin A. Power to the People. South Wales: University of South Wales Press, 1982.Green, Martin A. Power to the People. South Wales: University of South Wales Press, 1982.
• Green, Martin A.Green, Martin A. Solar Cells: Operating Principles, Technology, and System ApplicationsSolar Cells: Operating Principles, Technology, and System Applications. South Wales: University of. South Wales: University of
South Wales Press, 1982.South Wales Press, 1982.
• ““How Solar Cells Work.” 19 April 2002How Solar Cells Work.” 19 April 2002 http://www.howstuffworks.com/solar-cell1.htmhttp://www.howstuffworks.com/solar-cell1.htm
• Maycock, Paul D., and Edward N. Stirewalt.Maycock, Paul D., and Edward N. Stirewalt. Photovoltaics: Sunlight to Electricity in One Step.Photovoltaics: Sunlight to Electricity in One Step.
Massachusetts: Brick House Publishing Co., 1981.Massachusetts: Brick House Publishing Co., 1981.
• Merrigan, Joseph A.Merrigan, Joseph A. Sunlight to Electricity: Prospects for Solar Energy Conversion by PhotovoltaicsSunlight to Electricity: Prospects for Solar Energy Conversion by Photovoltaics Massachusetts: MITMassachusetts: MIT
Press, 1975. Press, 1975.
• ““Solar Cell Principles and Applications.” 19 April 2002Solar Cell Principles and Applications.” 19 April 2002 acre.murdoch.edu.au/refiles/pv/text.htmlacre.murdoch.edu.au/refiles/pv/text.html
APPLICATION OF SOLARAPPLICATION OF SOLAR
Associate ProfessorAssociate Professor
Thiagarajar College ofThiagarajar College of
Madurai – 625 015.Madurai – 625 015.
LIST OF APPLICATIONSLIST OF APPLICATIONS
• Solar Water HeatingSolar Water Heating
• Space Heating & CoolingSpace Heating & Cooling
• Solar Thermal Energy ConversionSolar Thermal Energy Conversion
• Photovoltaic Energy ConversionPhotovoltaic Energy Conversion
• Solar DistillationSolar Distillation
• Solar PumpingSolar Pumping
• Agricultural & Industrial Process heatAgricultural & Industrial Process heat
• Solar FurnaceSolar Furnace
• Solar CookingSolar Cooking
• Solar Production of HydrogenSolar Production of Hydrogen
• Solar Green HousesSolar Green Houses
SOLAR WATER HEATINGSOLAR WATER HEATING
• Proven technologyProven technology
• Widely usedWidely used
• Various Techniques areVarious Techniques are
• Thermo siphonThermo siphon
• Closed loopClosed loop
SPACE HEATINGSPACE HEATING
• Direct gainDirect gain
• Thermal Storage wallThermal Storage wall
• Attached sun spaceAttached sun space
• Convective LoopConvective Loop
ROOF STORAGE OF SOLARROOF STORAGE OF SOLAR
CONVECTIVE LOOP PASSIVECONVECTIVE LOOP PASSIVE
SOLAR HEATINGSOLAR HEATING
SPACE COOLINGSPACE COOLING
ABSORPTION AIR-CONDITIONINGABSORPTION AIR-CONDITIONING
• Lithium Bromide Water systemLithium Bromide Water system
• Water vapour is a refrigerantWater vapour is a refrigerant
• 85 to 9585 to 95°C is enough & achievable°C is enough & achievable
with flat plate collectorswith flat plate collectors
• Heat is supplied to the solution ofHeat is supplied to the solution of
refrigerant (Water Vapour)refrigerant (Water Vapour)
• LiBr-HLiBr-H22O system consists ofO system consists of
• Solar Collector & StorageSolar Collector & Storage
• Absorption Air-conditioners &Absorption Air-conditioners &
Auxiliary heatingAuxiliary heating
SOLAR OPERATEDSOLAR OPERATED
ABSORPTION AIR CONDITIONERABSORPTION AIR CONDITIONER
WORKING PRINCIPLE OF LIBR-WORKING PRINCIPLE OF LIBR-
HH22O SYSTEMO SYSTEM
• Heat is supplied to a solution of refrigerant in the absorbentHeat is supplied to a solution of refrigerant in the absorbent
• Where refrigerant is distilled out of the absorbent fluidWhere refrigerant is distilled out of the absorbent fluid
• Refrigerant (In liquid) is condensed & Goes thro’ a PressureRefrigerant (In liquid) is condensed & Goes thro’ a Pressure
Reducing Valve (PRV) to the evaporatorReducing Valve (PRV) to the evaporator
• Where it operates & cools air / water for space coolingWhere it operates & cools air / water for space cooling
• The solar intensity varies the capacity of the coolerThe solar intensity varies the capacity of the cooler
SOLAR THERMAL ELECTRICSOLAR THERMAL ELECTRIC
• Solar energy is utilized to heatSolar energy is utilized to heat
working fluidworking fluid
• Gas, Water or Other volatile liquidGas, Water or Other volatile liquid
• Energy is first collected by using aEnergy is first collected by using a
solar pondsolar pond
• With a help of flat / focusing typeWith a help of flat / focusing type
• Heat energy is converted intoHeat energy is converted into
mechanical energy in the turbinemechanical energy in the turbine
• Finally the turbine drive the GeneratorFinally the turbine drive the Generator
• Solar Thermal power generation employsSolar Thermal power generation employs
• Low, Medium & High temp. cyclesLow, Medium & High temp. cycles
• For Efficient conversion of heat energy toFor Efficient conversion of heat energy to
mechanical energymechanical energy
• Working fluid to be supplied to turbine atWorking fluid to be supplied to turbine at
High Temp.High Temp.
LOW TEMPERATURE CYCLELOW TEMPERATURE CYCLE
• Working temp. Max. is limited to 100Working temp. Max. is limited to 100°°CC
• Rankine cycle is preferred for ThermalRankine cycle is preferred for Thermal
to Mechanical energy conversionto Mechanical energy conversion
• Use flat plate collectorsUse flat plate collectors
• Poor efficiency of the turbine systemPoor efficiency of the turbine system
• Since operating temperature is lowSince operating temperature is low
SOLAR COLLECTOR TYPESOLAR COLLECTOR TYPE
LOW TEMP. SOLAR POWER PLANTLOW TEMP. SOLAR POWER PLANT
MEDIUM TEMPERATURE CYCLEMEDIUM TEMPERATURE CYCLE
• Work at temp. between 150 to 300Work at temp. between 150 to 300°°CC
• Rankine cycle is preferred for Thermal toRankine cycle is preferred for Thermal to
Mechanical energy conversionMechanical energy conversion
• Temp. above 175Temp. above 175°°C requires to useC requires to use
focusing / concentrating collectorsfocusing / concentrating collectors
• Used where ample sunshineUsed where ample sunshine
• Solar Energy conversion done in twoSolar Energy conversion done in two
• Central Receiver SystemCentral Receiver System
• Distributed collector systemDistributed collector system
CENTRAL RECEIVER SYSTEMCENTRAL RECEIVER SYSTEM
• Commonly known as power tower designCommonly known as power tower design
• An array of sun tracking mirrors (heliostats) reflects solar radiationAn array of sun tracking mirrors (heliostats) reflects solar radiation
• Into a receiver mounted on the top of a central towerInto a receiver mounted on the top of a central tower
• Solar energy absorbed in the central receiver is removed as heat bySolar energy absorbed in the central receiver is removed as heat by
means of heat transportmeans of heat transport
• Convert into Mechanical energy in the turbine and then convertedConvert into Mechanical energy in the turbine and then converted
into electrical energyinto electrical energy
DISTRIBUTED COLLECTORDISTRIBUTED COLLECTOR
SYSTEMSYSTEM Consist of No. of Parabolic trough collectors / Parabolic dish typeConsist of No. of Parabolic trough collectors / Parabolic dish type
Absorber pipes (Receivers) of individual collector are connectedAbsorber pipes (Receivers) of individual collector are connected
To carry away the heated fluid to a single locationTo carry away the heated fluid to a single location
Heated fluid is pass thro’ a turbine to convert thermal toHeated fluid is pass thro’ a turbine to convert thermal to
mechanical energymechanical energy
Finally mechanical energy is converted into electrical energyFinally mechanical energy is converted into electrical energy
Limited to Smaller size of power plant applicationLimited to Smaller size of power plant application
HIGH TEMPERATURE CYCLEHIGH TEMPERATURE CYCLE
• Work at a temp. above 300Work at a temp. above 300°°CC
• Rankine, Bryton & Stirling cyclesRankine, Bryton & Stirling cycles
are being used for Thermal toare being used for Thermal to
Mechanical energy conversionMechanical energy conversion
• Central receiver type of solarCentral receiver type of solar
collectors are usedcollectors are used
• Larger size of power generation isLarger size of power generation is
THERMAL ELECTRICTHERMAL ELECTRIC
CONVERSION SYSTEMSCONVERSION SYSTEMS
• Energy is first collected by using a solarEnergy is first collected by using a solar
pond – Brine Solutionpond – Brine Solution
• By using a flat plate / focusing collectorBy using a flat plate / focusing collector
• This energy is used to increaseThis energy is used to increase
• Internal energy of a temperature of aInternal energy of a temperature of a
• Organic Fluid may be directly using aOrganic Fluid may be directly using a
Rankine, Brayton or Stirling cycleRankine, Brayton or Stirling cycle
• To convert heat to mechanical energyTo convert heat to mechanical energy
SOLAR PONDSOLAR POND
ELECTRIC POWER PLANTELECTRIC POWER PLANT
PHOTO-VOLTAIC POWERPHOTO-VOLTAIC POWER
•System Consists ofSystem Consists of
• Solar Cell arraySolar Cell array
• Load LevelerLoad Leveler
• Storage SystemStorage System
• Tracking SystemTracking System
PHOTOVOLTAIC SYSTEMPHOTOVOLTAIC SYSTEM
INTEGRATED WITH POWER GRIDINTEGRATED WITH POWER GRID
AGRICULTURAL & INDUSTRIALAGRICULTURAL & INDUSTRIAL
PROCESS HEATPROCESS HEAT
• Classification of ApplicationsClassification of Applications
• Low temperatures below 100Low temperatures below 100°°CC
• Intermediate temperature 100 toIntermediate temperature 100 to
• High temperature above 175High temperature above 175°°CC
LOW TEMPERATURELOW TEMPERATURE
• Flat plat collectorsFlat plat collectors
• Drying of Grains, peanut pods, TeaDrying of Grains, peanut pods, Tea
leaves & Coffee beansleaves & Coffee beans
• Salty water into potable waterSalty water into potable water
• Space heating of livestock shelters,Space heating of livestock shelters,
Dairy farms & Poultry housesDairy farms & Poultry houses
INTERMEDIATE TEMPERATUREINTERMEDIATE TEMPERATURE
• Uses Flat plate collectors followed by anUses Flat plate collectors followed by an
array of parabolic trough concentratingarray of parabolic trough concentrating
• Laundry, Fabric dying, Food processingLaundry, Fabric dying, Food processing
and Can washing, Kraft pulpingand Can washing, Kraft pulping
• Laminating & Drying of glass fiberLaminating & Drying of glass fiber
• Drying & Baking in Automobile andDrying & Baking in Automobile and
HIGH TEMPERATUREHIGH TEMPERATURE
• Pumping of Irrigation waterPumping of Irrigation water
• Treatment of Industrial EffluentTreatment of Industrial Effluent
SOLAR DISTILLATIONSOLAR DISTILLATION
• Converting saline water intoConverting saline water into
distilled waterdistilled water
• Consists of blackened basinConsists of blackened basin
containing saline water at a shallowcontaining saline water at a shallow
• Over which a transparent air tightOver which a transparent air tight
cover that encloses completely thecover that encloses completely the
space above the basinspace above the basin
• Solar radiation pass thro’ the cover isSolar radiation pass thro’ the cover is
absorbed & converted into heat in theabsorbed & converted into heat in the
black surfaceblack surface
• Saline water in the basin is heated &Saline water in the basin is heated &
water vapour produced - condensed aswater vapour produced - condensed as
purified waterpurified water
• Transparent roof material transmits allTransparent roof material transmits all
radiation falling on it & remains coolradiation falling on it & remains cool
enough to condense water vapourenough to condense water vapour
SOLAR PUMPINGSOLAR PUMPING
• Utilizing the power generated by solar energy for waterUtilizing the power generated by solar energy for water
• Solar Pumping system Consist ofSolar Pumping system Consist of
• Solar CollectorsSolar Collectors
• Heat transport systemHeat transport system
• Heat exchangerHeat exchanger
• Heat EngineHeat Engine
• Water PumpWater Pump
SCHEMATIC OF A SOLAR PUMPSCHEMATIC OF A SOLAR PUMP
SOLAR FURNACESOLAR FURNACE
• An equipment to get high temp. by concentrating solar radiationAn equipment to get high temp. by concentrating solar radiation
• Parabolic Concentrator is used (Aluminium polished)Parabolic Concentrator is used (Aluminium polished)
• Where the solar radiation is concentratedWhere the solar radiation is concentrated
• No. of Heliostats (turn able mirrors) are usedNo. of Heliostats (turn able mirrors) are used
• To focus the solar radiation to the parabolic concentratorTo focus the solar radiation to the parabolic concentrator
• Collector focus the the radiation in a small volume (Receiver)Collector focus the the radiation in a small volume (Receiver)
• A Solar tracking system is moving the heliostat to divert theA Solar tracking system is moving the heliostat to divert the
radiation towards the concentratorradiation towards the concentrator
PRINCIPLE OF SOLAR FURNACEPRINCIPLE OF SOLAR FURNACE
ADVANTAGES OF SOLARADVANTAGES OF SOLAR
• Heating is carried out without anyHeating is carried out without any
• Temp. is easily controlled by changingTemp. is easily controlled by changing
the position of the material in focusthe position of the material in focus
• Extremely high temp. is achievableExtremely high temp. is achievable
• Provides rapid heating & coolingProvides rapid heating & cooling
LIMITATIONS – SOLAR FURNACELIMITATIONS – SOLAR FURNACE
•Limited to sunny day applicationLimited to sunny day application
• During Bright sunshine only – 4During Bright sunshine only – 4
to 5 Hrsto 5 Hrs
•High CostHigh Cost
SOLAR COOKINGSOLAR COOKING
• Flat plate type solar cooker with or without reflectorFlat plate type solar cooker with or without reflector
• Maximum no load temp. with a single reflector reaches up to 160Maximum no load temp. with a single reflector reaches up to 160°°CC
• Multi reflector type solar ovenMulti reflector type solar oven
• Four Square or Triangular or Rectangular reflectors are mounted – upFour Square or Triangular or Rectangular reflectors are mounted – up
to 200to 200°°CC
• Parabolic disc concentrator typeParabolic disc concentrator type
• Solar Radiations concentrated onto a focal pointSolar Radiations concentrated onto a focal point
• Up to 450Up to 450°°C can be achievedC can be achieved
PRINCIPLE OF BOX TYPEPRINCIPLE OF BOX TYPE
REFLECTOR TYPE SOLARREFLECTOR TYPE SOLAR
PRINCIPLE OF CONCENTRATINGPRINCIPLE OF CONCENTRATING
TYPE COOKERTYPE COOKER
MERITS OF SOLAR COOKERMERITS OF SOLAR COOKER
• No attention is requiredNo attention is required
• No fuel is requiredNo fuel is required
• Negligible maintenanceNegligible maintenance
• No pollutionNo pollution
• Vitamins of the food are not destroyedVitamins of the food are not destroyed
• No problem of charring & no overNo problem of charring & no over
flowing of foodflowing of food
LIMITATIONS OF SOLARLIMITATIONS OF SOLAR
• Cook according to the sunshineCook according to the sunshine
• Menu has to be preplannedMenu has to be preplanned
• One can not cook short noticeOne can not cook short notice
• Can not cook during night & cloudyCan not cook during night & cloudy
• Takes comparatively more timeTakes comparatively more time
• Chapattis are not cooked – SinceChapattis are not cooked – Since
high temp. requirementhigh temp. requirement
SOLAR GREEN HOUSESSOLAR GREEN HOUSES
• A Structure covered with transparent materialA Structure covered with transparent material
• Is a growth chamberIs a growth chamber
• Which offers the possibilities of year round plant productionWhich offers the possibilities of year round plant production
• Green houses attached to a residence creates a pleasantGreen houses attached to a residence creates a pleasant
• In physical & mental environment of occupantIn physical & mental environment of occupant
• Designed truly passive solar collection mannerDesigned truly passive solar collection manner
• With a well applied heat storeWith a well applied heat store
• Helps crop cultivation under controlled environmentHelps crop cultivation under controlled environment
GREEN HOUSESGREEN HOUSES
•Create a micro climateCreate a micro climate
•Results in several fold increaseResults in several fold increase
in crop photosynthesisin crop photosynthesis
• Summer Green HousesSummer Green Houses
• Winter Green HousesWinter Green Houses
GOTHIC ARCH GREEN HOUSEGOTHIC ARCH GREEN HOUSE
PARAMETERS FOR PLANTPARAMETERS FOR PLANT
GROWTHGROWTH• Light – Essential requirementLight – Essential requirement
• Plants are found to use only radiant energy in the visible & nearPlants are found to use only radiant energy in the visible & near
visible portion of spectrumvisible portion of spectrum
• Grow quite well at intensities of 27500 Lux (1/4Grow quite well at intensities of 27500 Lux (1/4thth
Full sun light)Full sun light)
• 16500 Lux – also for good plant growth16500 Lux – also for good plant growth
• Dominant environmental factorDominant environmental factor
• Different optimum temp. for each stage of plant developmentDifferent optimum temp. for each stage of plant development
• Comfortable temp. 10 to 25Comfortable temp. 10 to 25°°CC
• Soil TemperatureSoil Temperature
• 20 to 2520 to 25°°C reported to be optimumC reported to be optimum
• Temp. determines the ability of a plantTemp. determines the ability of a plant
to absorb water from soilto absorb water from soil
• Low soil temp. are widely reportedLow soil temp. are widely reported
good for young plantsgood for young plants
• High soil temp. are recommended forHigh soil temp. are recommended for
rooting plants or germinating seedsrooting plants or germinating seeds
• Air movementsAir movements
• Influences the transpiration, evaporationInfluences the transpiration, evaporation
of water from soil & availability of COof water from soil & availability of CO22
• Optimum growth has been reported at aOptimum growth has been reported at a
speed of 0.8 to 2 cm/secspeed of 0.8 to 2 cm/sec
• Affects plant growthAffects plant growth
• High humidity – plant susceptible toHigh humidity – plant susceptible to
diseases due to pathogenic organismsdiseases due to pathogenic organisms
• High humidity also results in taller plantsHigh humidity also results in taller plants
• Low humidity increases the evaporationLow humidity increases the evaporation
rate & requires more waterrate & requires more water
• Ideal humidity level is 55 to 65% @ 21 toIdeal humidity level is 55 to 65% @ 21 to
PIPE FRAMED GREEN HOUSESPIPE FRAMED GREEN HOUSES