储能技术应用

ApplicationofEnergyStorage,ImportanceofES,ThrustforRenewableEnergysourcesVariableoutputsEnergyBufferingImportanceinthepresentcontextWhynewtechnologiesanddevices?,DifferentTypesofES,EScanbeclassifiedasMechanicalEnergyStorage.MagneticEnergyStorage.ThermalEnergyStorage.ChemicalEnergyStorage.,MechanicalEnergyStorageFlyWheels,Principle:EnergyisstoredintheformofMechanicalEnergy.Lightweightfibercompositematerialsareusedtoincreaseefficiency.Energydensity=0.05MJ/Kg,=0.8,TheEnergyDensityisdefinedastheEnergyperunitmass:Where,Visthecircularvelocityoftheflywheelisthespecificstrengthofamaterialisthedensityofthematerial,Propertiesofsomematerialsusedforbuildingflywheels.,Advantagesanddisadvantages:Verycompactwhencomparedtootherenergystoragesystems.Flywheelsareusedforstartingandbrakinglocomotives.Aflywheelispreferredduetolightweightandhighenergycapacity.Itisnoteconomicalasithadalimitedamountofcharge/dischargecycle.,CompressedAirEnergyStorage,Operation:Usesoff-peakelectricitytocompressairandstoreitinairtightundergroundcaverns.Whentheairisreleasedfromstorage,itexpandsthroughacombustionturbinetocreateelectricity.Energydensity=0.22MJ/Kg,=0.5Advantagesanddisadvantages:Faststart-up.Drawback-Geologicalstructurereliance,PumpedHydroelectricEnergyStorage,until1970,itwastheonlycommerciallyavailableoptionforstoringenergy,Operation:Itconsistsoftwolargereservoirslocatedatdifferentelevations.Duringpeakdemand,waterisreleasedfromtheupperreservoir.IfProductionexceedsDemand,waterispumpedupandstoredintheupperreservoir.PumpusedisaCombinedMotorandDynamo.,Advantagesanddisadvantages:Mosteffectivewithlargestcapacityofelectricity(over2000MW).Energydensity=0.001MJ/Kg,=0.8Geographicaldependence.Thecapitalcostismassive.Soilerosion,landinundation,Siltingofdams.,MagneticEnergyStorageSuperConductors,SMESsystemsstoreenergyinamagneticfieldcreatedbytheflowofdirectcurrentinacoilofsuperconductingmaterialthathasbeencryogenicallycooled.Principle:Atlow-temperatures,electriccurrentsencounteralmostnoresistance.Storesenergyinthemagneticfield.EnvironmentalfriendlyandHighlyefficient.,Dependingonthepeakfieldandratioofthecoilsheightanddiametercapacityofstoragevaries.,SuperCapacitors,UseofthinfilmpolymersforthedielectriclayerCarbonnanotubesandpolymersarepracticalforsupercapacitorsInfuture-carbonnanotubeswithceramicsReducetheeffectoffluctuationsLongerlifetimewhichreducesmaintenancecosts.,ElectrochemicalStorage,TypesofBatteries:SmallCapacitiesLead-AcidBatteriesTheyuseachemicalreactiontodoworkonchargeandproduceavoltagebetweentheiroutputterminals.Energydensityis0.6MJ/Kg.Efficiencyofthecellisonly15%LargeScale,WorkingofaLeadacidBattery,Under-GroundThermalEnergyStorage,Usingmethodsofheatexchange1.Aquiferthermalstorage-Usageofundergroundwater2.Ductthermalstorage-UsageofPlasticTubesEnvironmentalimpactEg:De-icefrozenroads,ApplicationofThermalEnergyStorage,AirConditioning:Asalthydrateactsasacoolheatsinkfortheairconditionerworkingfluid.Thestoredheatisrejectedfromthesalthydrateduringnighttoheatthesurroundingair.Energydensity=0.25MJ/Kg,=0.8E.g.:SodiumSulfateDecahydrate.,FuelCells,DirectconversionEnergyElectricityBurningFuel?HighEfficiencyApplications:E.g.:NASA,Viablealternativetopetrolengines.,Typesoffuelcells:Classifiedonthebasisofoperatingconditionsandvariouselectrolytesused.Alkalinefuelcells(AFC)Polymerelectrolytemembrane(PEM)Phosphoricacidfuelcells(PAFC)Moltencarbonatefuelcells(MCFC)Solidoxidefuelcells(SOFC)Regenerativefuelcells,Energydensitiesofsomeenergystoragemethods.,Advantages:NogreenhousegasesNotmuchpoliticaldependenceMoreoperatingtime.Disadvantages:StorageofHydrogenduetohighlyinflammablenatureofH2.Thoughmetalhydrides(FeTiH1.7)andNH3canbealternative.HighcapitalcostduetoPlatinumcatalystusedintheprocess.,Whichisbetter?,Comparingonemethodofenergystoragewithanotherispointless.Thereason-Noneofthemareoptimalforallpurposes.Differentstoragemethodsdifferincapacityandmaximumusablestoragetime.,ForlargescalestorageUndergroundthermal,pumpedhydroandcompressedairenergystoragesystemsarepreferable.Superconductorscanstoreenergywithnegligiblelosses.Fuelcellsareaviablealternativetopetrolenginesduetotheirhighefficiency.Flywheelshaveanarrowrangeandarenotananswerforlargescaleoperations.,Conclusion:,Reliablean