Upload
others
View
4
Download
0
Embed Size (px)
Citation preview
1
Material for Energy and Environmental Sustainability
PDT 463
Solar Energy
Dr. Norshah Aizat Shuaib
Page3
Recapfromlastlecture
u Coal–typesofmining
u Coalandnuclear–howdotheygenerateelectric
u Nuclearfission-theprocess
u Nucleardisasters–givetwoexamples
Page5
What is Solar Energy?
n OriginateswiththethermonuclearfusionreacGonsoccurringinthesun.
n RepresentstheenGreelectromagneGcradiaGon(visiblelight,infrared,ultraviolet,x-rays,andradiowaves).
n RadiantenergyfromthesunhaspoweredlifeonEarthformanymillionsofyears.
Page6
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.
Page7
Twotypesofsolarenergy:Solarthermalandsolarphotovoltaic
Solarphotovoltaicu Photovoltaic,orPVenergyconversion,ontheotherhand,directly
convertsthesun'slightintoelectricity.ThismeansthatsolarpanelsareonlyeffecGveduringdaylighthoursbecausestoringelectricityisnotaparGcularlyefficientprocess.
§Heatstorageisafareasierandefficientmethod,whichiswhatmakessolarthermalsoa[racGveforlarge-scaleenergyproducGon.§Heatcanbestoredduringthedayandthenconvertedintoelectricityatnight.SolarthermalplantsthathavestoragecapaciGescandrasGcallyimproveboththeeconomicsandthedispatchabilityofsolarelectricity.
Page9
Principleofopera@on:PhotovoltaicCell
1. Sunlightiscomposedofphotons,orbundlesofradiantenergy.
2. WhenphotonsstrikeaPVcell,theymaybereflectedorabsorbed(transmi[edthroughthecell).Onlytheabsorbedphotonsgenerateelectricity.
3. Whenthephotonsareabsorbed,theenergyofthephotonsistransferredtoelectronsintheatomsofthesolarcell.
Page10
Principleofopera@on:PhotovoltaicCell
4. Solarcellsareusuallymadeoftwothinpiecesofsilicon.
5. Onepieceofsiliconhasasmallamountoftheelementboronaddedtoit,whichgivesitatendencytoa[ractelectrons.Itiscalledthep-
layerbecauseofitsposiGvetendency.
6. Theotherpieceofsiliconhasasmallamountoftheelement
phosphorousaddedtoit,givingitanexcessoffreeelectrons(andanegaGvetendency).Thisiscalledthen-layerbecauseithasa
tendencytogiveupnegaGvelychargedelectrons.
Page11
Principleofopera@on:PhotovoltaicCell
7. WhenaphotonstrikesthePVcell,itsenergyisusedto“push”oneoftheextraelectronscontainedonthen-
layer(negaGvelayer)ofsiliconintothecircuit.
8. The“pushed”electronwilltravelthroughthecircuitunGlitreachesa
“hole”inthep-layer(posiGvelayer)ofsilicon,givingusanelectricalcurrentasittravels
Page12
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.
Page13
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.
Page14
u Energyfromthesuncanalsobegatheredtouseasasourceofheat.
u Passivesolarheatstructureshavenomovingparts,butusesouth-facingwindowstogatherandabsorbasmuchsolarheataspossible.
14
SolarHea@ng
Page1515
u AcGvesolarheatstructurespumpwateroranotherliquidthroughacollector.u CanbeusedforhouseholdradiantheaGng,orasasourceofhotwaterforshowersandcooking.
Imagesource:www.almeriaspas.com
Page16
Solar Energy to Heat Living Spaces
n Properdesignofabuildingisforittoactasasolarcollectorandstorageunit.Thisisachievedthroughthreeelements:insula@on,collec@on,andstorage.
Page20
PleasesitinyourlabgroupGrouprepresentaGvepleasecometomeandpickatopicYouwillbegiven10minutestoprepare,eachgroupwillgiveaveryshortpresentaGon(lessthan1minutepergroup)totheclass.
Page21
Discussion
21
• ChallengesofusingsolarenergyinMalaysia• ChallengesofusingsolarenergyinPerlis• Whysolarenergycarisuseless?• SolarenergykityoucanbuyfromLazada/Lelong.com.mywebsite
• Windenergyorsolarenergy:Whichoneisbe[erforMalaysia?
• ThinkaboutasystemthatcanbepoweredusingsolarenergyinUniCITIALAMcampus
• SolarenergysystemcurrentlyusedinUniMAPcampus(GetSol)
• SolarcatfeedingsystembyastudentfromSKPutra,Kangar