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Material for Energy and Environmental Sustainability

PDT 463

Solar Energy

Dr. Norshah Aizat Shuaib

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Agendafortoday

u Recapfromlastweek

u Midtermtest

u Solarenergy

u Groupdiscussion

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Recapfromlastlecture

u Coal–typesofmining

u Coalandnuclear–howdotheygenerateelectric

u Nuclearfission-theprocess

u Nucleardisasters–givetwoexamples

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WhereissolarenergyinPerlis?

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What is Solar Energy?

n OriginateswiththethermonuclearfusionreacGonsoccurringinthesun.

n  RepresentstheenGreelectromagneGcradiaGon(visiblelight,infrared,ultraviolet,x-rays,andradiowaves).

n  RadiantenergyfromthesunhaspoweredlifeonEarthformanymillionsofyears.

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Twotypesofsolarenergy:Solarthermalandsolarphotovoltaic

Solarthermalu  SolarthermalelectricenergygeneraGonconcentratesthelightfrom

thesuntocreateheat,andthatheatisusedtorunaheatengine,whichturnsageneratortomakeelectricity.

u  Theworkingfluidthatisheatedbytheconcentratedsunlightcanbealiquidoragas.

u  Differentworkingfluidsincludewater,oil,salts,air,nitrogen,helium,etc.Differentenginetypesincludesteamengines,gasturbines,SGrlingengines,etc.

u  §Alloftheseenginescanbequiteefficient,oVenbetween30%and40%,andarecapableofproducing10'sto100'sofmegawa[sofpower.

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Twotypesofsolarenergy:Solarthermalandsolarphotovoltaic

Solarphotovoltaicu  Photovoltaic,orPVenergyconversion,ontheotherhand,directly

convertsthesun'slightintoelectricity.ThismeansthatsolarpanelsareonlyeffecGveduringdaylighthoursbecausestoringelectricityisnotaparGcularlyefficientprocess.

§Heatstorageisafareasierandefficientmethod,whichiswhatmakessolarthermalsoa[racGveforlarge-scaleenergyproducGon.§Heatcanbestoredduringthedayandthenconvertedintoelectricityatnight.SolarthermalplantsthathavestoragecapaciGescandrasGcallyimproveboththeeconomicsandthedispatchabilityofsolarelectricity.

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Photovoltaics

n Photo+voltaic=convertlighttoelectricity

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Principleofopera@on:PhotovoltaicCell

1.  Sunlightiscomposedofphotons,orbundlesofradiantenergy.

2.  WhenphotonsstrikeaPVcell,theymaybereflectedorabsorbed(transmi[edthroughthecell).Onlytheabsorbedphotonsgenerateelectricity.

3.  Whenthephotonsareabsorbed,theenergyofthephotonsistransferredtoelectronsintheatomsofthesolarcell.

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Principleofopera@on:PhotovoltaicCell

4.  Solarcellsareusuallymadeoftwothinpiecesofsilicon.

5.  Onepieceofsiliconhasasmallamountoftheelementboronaddedtoit,whichgivesitatendencytoa[ractelectrons.Itiscalledthep-

layerbecauseofitsposiGvetendency.

6.  Theotherpieceofsiliconhasasmallamountoftheelement

phosphorousaddedtoit,givingitanexcessoffreeelectrons(andanegaGvetendency).Thisiscalledthen-layerbecauseithasa

tendencytogiveupnegaGvelychargedelectrons.

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Principleofopera@on:PhotovoltaicCell

7.  WhenaphotonstrikesthePVcell,itsenergyisusedto“push”oneoftheextraelectronscontainedonthen-

layer(negaGvelayer)ofsiliconintothecircuit.

8.  The“pushed”electronwilltravelthroughthecircuitunGlitreachesa

“hole”inthep-layer(posiGvelayer)ofsilicon,givingusanelectricalcurrentasittravels

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Advantages and Disadvantages u  Advantages

u All chemical and radioactive polluting byproducts of the thermonuclear reactions remain behind on the sun, while only pure radiant energy reaches the Earth.

u Energy reaching the earth is incredible. By one calculation, 30 days of sunshine striking the Earth have the energy equivalent of the total of all the planet’s fossil fuels, both used and unused.

u  Disadvantages

u Sun does not shine consistently.

u Solar energy is a diffuse source. To harness it, we must concentrate it into an amount and form that we can use, such as heat and electricity.

u Addressed by approaching the problem through:

1) collection, 2) conversion, 3) storage.

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Example Application: Solar Energy to Heat Water

u A flat-plate collector is used to absorb the sun’s energy to heat the water.

u The water circulates throughout the closed system due to convection currents.

u Tanks of hot water are used as storage.

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u Energyfromthesuncanalsobegatheredtouseasasourceofheat.

u Passivesolarheatstructureshavenomovingparts,butusesouth-facingwindowstogatherandabsorbasmuchsolarheataspossible.

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SolarHea@ng

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u AcGvesolarheatstructurespumpwateroranotherliquidthroughacollector.u CanbeusedforhouseholdradiantheaGng,orasasourceofhotwaterforshowersandcooking.

Imagesource:www.almeriaspas.com

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Solar Energy to Heat Living Spaces

n  Properdesignofabuildingisforittoactasasolarcollectorandstorageunit.Thisisachievedthroughthreeelements:insula@on,collec@on,andstorage.

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SpaceHea@ngThroughPassiveSolar

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PassiveSolar

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Ac@veSolarHea@ng

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PleasesitinyourlabgroupGrouprepresentaGvepleasecometomeandpickatopicYouwillbegiven10minutestoprepare,eachgroupwillgiveaveryshortpresentaGon(lessthan1minutepergroup)totheclass.

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Discussion

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•  ChallengesofusingsolarenergyinMalaysia•  ChallengesofusingsolarenergyinPerlis•  Whysolarenergycarisuseless?•  SolarenergykityoucanbuyfromLazada/Lelong.com.mywebsite

•  Windenergyorsolarenergy:Whichoneisbe[erforMalaysia?

•  ThinkaboutasystemthatcanbepoweredusingsolarenergyinUniCITIALAMcampus

•  SolarenergysystemcurrentlyusedinUniMAPcampus(GetSol)

•  SolarcatfeedingsystembyastudentfromSKPutra,Kangar

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References

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1.   FundamentalsofMaterialsforEnergyandEnvironmentalSustainability,

Ginley,DavidS;Cahen,David,CambridgeUniversityPress,2012

2.   Energyinthe21stCentury,JohnRFanchi,WorldScienGfic,2013

3.  h[p://slideplayer.com/slide/6981942/