Jet Za Internet Celotna - Volume 2 - Issue 3 - August 2009

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    JET

    JOURNAL OF ENERGY TECHNOLOGY

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    JET

    VOLUME 2 / Issue 3

    RevijaJournalofEnergyTechnology(JET)jeindeksiranavnaslednjihbazah:INSPEC,CambridgeScientific Abstracts: Abstracts in New Technologies and Engineering (CSA ANTE), ProQuest'sTechnologyResearchDatabase.The JournalofEnergyTechnology (JET) is indexedandabstracted in the followingdatabases:INSPEC

    ,CambridgeScientificAbstracts:Abstracts inNewTechnologiesandEngineering (CSA

    ANTE),andProQuest'sTechnologyResearchDatabase.

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    JET

    JOURNAL OF ENERGY TECHNOLOGY

    Ustanovitelji/FOUNDERSFakultetazaenergetiko,UNIVERZAVMARIBORU/

    FACULTYOFENERGYTECHNOLOGY,UNIVERSITYOFMARIBOR

    Izdajatelj/PUBLISHER

    Fakultetazaenergetiko,UNIVERZAVMARIBORU/

    FACULTYOFENERGYTECHNOLOGY,UNIVERSITYOFMARIBOR

    Izdajateljskisvet/PUBLISHINGCOUNCIL

    Zasl.Prof.dr.DaliONLAGI,

    UniverzavMariboru,Slovenija,predsednik/UniversityofMaribor,Slovenia,President

    Prof.dr.BrunoCVIKL,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.ddr.DenisONLAGI,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.DaniloFERETI,

    SveuiliteuZagrebu,Hrvaka/UniversityinZagreb,Croatia

    Prof.dr.RomanKLASINC,

    TechnischeUniversittGraz,Avstrija/GrazUniversityOfTechnology,Austria

    Prof.dr.AlfredLEIPERTZ,

    UniversittErlangen,Nemija/UniversityofErlangen,Germany

    Prof.dr.MilanMARI,UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.BranimirMATIJAEVI,SveuiliteuZagrebu,Hrvaka/UniversityinZagreb,Croatia

    Prof.dr.BorutMAVKO,

    IntitutJoefStefan,Slovenija/JozefStefanInstitute,Slovenia

    Prof.dr.GregNATERER,

    UniversityofOntario,Kanada/UniversityofOntario,Canada

    Prof.dr.EnrikoNOBILE,

    UniversitdegliStudidiTrieste,Italia/UniversityofTrieste,Italy

    Prof.dr.IztokPOTR,UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.AndrejPREDIN,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Profdr.MatjaRAVNIK,IntitutJoefStefan,Slovenija/JozefStefanInstitute,Slovenia

    Prof.dr.JoeVORI,UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.KoichiWATANABE,

    KEIOUniversity,Japonska/KEIOUniversity,Japan

    Odgovorniurednik/EDITORINCHIEF

    AndrejPREDIN

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    JET

    Uredniki/COEDITORS

    JurijAVSEC

    GorazdHREN

    MilanMAR

    I

    IztokPOTR

    JanezUSENIK

    JoeVORI

    JoePIHLER

    Urednikiodbor/EDITORIALBOARD

    Prof.dr.JurijAVSEC,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.ddr.DenisONLAGI,

    UniverzavMariboru,Slovenija/UniversityofMaribor,SloveniaProf.dr.RomanKLASINC,

    TechnischeUniversittGraz,Avstrija/GrazUniversityOfTechnology,Austria

    Prof.dr.JurijKROPE,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.AlfredLEIPERTZ,

    UniversittErlangen,Nemija/UniversityofErlangen,Germany

    Prof.dr.BranimirMATIJAEVI,

    SveuiliteuZagrebu,Hrvaka/UniversityofZagreb,Croatia

    Prof.dr.MatejMENCINGER,

    UniverzavMariboru,

    Slovenija

    /University

    of

    Maribor,

    Slovenia

    Prof.dr.GregNATERER,

    UniversityofOntario,Kanada/UniversityofOntario,Canada

    Prof.dr.EnrikoNOBILE,

    UniversitdegliStudidiTrieste,Italia/UniversityofTrieste,Italy

    Prof.dr.IztokPOTR,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.AndrejPREDIN,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.AleksandarSALJNIKOV,

    UniverzaBeograd,Srbija/UniversityofBeograd,Serbia

    Prof.dr.BraneIROK,

    UniverzavLjubljani,Slovenija/UniversityofLjubljana,Slovenia

    Prof.ddr.JanezUSENIK,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.JoeVORI,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Doc.dr.TomaAGAR,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Doc.dr.FrancERDIN,

    UniverzavMariboru,Slovenija/UniversityofMaribor,Slovenia

    Prof.dr.KoichiWATANABE,KEIOUniversity,Japonska/KEIOUniversity,Japan

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    Tehnikapodpora/TECHNICALSUPPORTJankoOMERZU

    SonjaNOVAK

    Izhajanjerevije/PUBLISHINGRevijaizhajatirikratletnovnakladi300izvodov.lankisodostopninaspletnistranirevije

    www.fe.unimb.si/si/ejet/index.php.

    Thejournalispublishedfourtimesayear.Articlesareavailableatthejournalshomepage

    www.fe.unimb.si/si/ejet/index.php.

    Lektoriranje/LanguageEditingTerryT.JACKSON

    Produkcija/PRODUCTIONVizualnekomunikacijecomTECd.o.o.

    Oblikovanjerevijeinznakarevije/JOURNALANDLOGODESIGNAndrejPREDIN

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    Slovenijanapotivnizkoogljinodrubo?

    Trajnostni razvoj energetike v Slovenijimora biti oblika razvoja, ki zadoa potrebam poenergiji, ne da bi pri tem ogroal okolje in s tem monosti ivljenja in razvoj prihodnjim

    generacijam,da prav tako zadostijo svojim potrebam.V tej smeri (vsajupam tako)je bilspisan tudi dokument Republike Slovenije, sveta vlade RS za konkurennost, StratekidokumentsektorskerazvojneskupineENERGETIKAINTRAJNOSTNIVIRIENERGIJE,zdne10

    novembra,2008.Vodseku,kjernavajapremogje zapisano,dapremogdanespredstavlja

    pomembenprimarnivirzaproizvodnjoelektrineenergije(vstrukturiproizvodnjepriblinotretjino proizvodnje elektrine energije v RS). Predvideno je, da se bo v prihodnosti

    proizvodnjaelektrineenergijeizpremogadoleta2030celopodvojila!?Vduhuzapisanega

    stratekegadokumentamebegaodloitev vladeRS, ki sejeodloila za izgradnjonovegablokaTE6,zzastarelotehnologijoseiganjapremogovegaprahupripovianemtlaku(CCT).Tatehnologijasejepojavilav90.letihprejnjegastoletja.(kombiniraniplinskoparniproces

    PCCinFBCtehnologiji).eboljerazmislimoinobpoznavanjutrendovrazvoja,bisemoralavlada odloiti vsaj za IGCC (Integrated Gasification Combined Cycle) tehnologijo, ki bi

    omogoalaVelenjskiotanjski regijinadaljnji razvojnapodrojuenergetike, tudikobodoizrpanezalogepremogavVelenju.Grezakombiniranplinskoparniprocesspredhodnim

    uplinjanjempremoga.Prednosttetehnologijejevmonostiuporabealternativnihgoriv,kotso: lesnabiomasa,odpadnaolja,naftniodpadki, komunalniodpadki.Ob temje zanimiva

    monost uporabe zemeljskega plina ob prikljuitvi Slovenije na Juni tok ruskegaplinovoda. V tem primeru je tehnoloki del elektrarne sestavljen iz turbin, ki lahkokoristijo razline vrste plinastih goriv. Ta novozgrajen blok bi v tem primeru deloval v

    strukturitrajnostnegaenergetskegarazvojaSlovenije.Strukturnobilahkobilvkljuenvsedo

    takrat,kobodotehnologijauporabeobnovljivihvirovenergije(OVE)takorazvita,dabomov

    Slovenijilahkopokrilivseenergetskepotrebe.

    IsSloveniaonthewaytolowlevelcarbonsociety?

    Sustainable energy development in Slovenia should perform as a development to fulfil

    today'senergyneedswithoutcompromisingtheenvironmentand,aboveall,giving future

    generations the possibilities of quality life and development of their own needs. In this

    direction (at least Ihopeso)waswrittentheStrategyPlanofDevelopmentofEnergyand

    SustainableEnergySourcesby theCouncilonCompetitivenessof theRepublicofSlovenia

    (dated10November,2008).Inthecoalsection, it isstatedthattodaycoal isan importantprimarysourceforelectricityproduction(representingonethirdofelectricityproductionin

    Sloveia).Itisenvisagedthatinthefuture,by2030,electricityproductionfromcoalwillhave

    doubled. In the spirit of the above strategy document, I am very surprised by the

    Government's decision for the implementation of a new TES 6 block, with outdated

    technology burning pulverised coal at an elevated pressure. This technology is from the

    1990s(combinedgassteamprocessPCCandFBCtechnology).Abetterconsiderationonthe

    partofthegovernment,withtheknowledgeoftodaysdevelopmenttrends,wouldbetheIGCC (Integrated Gasification Combined Cycle) technology, allowing the Velenjeotanjregion further development in the energy field, after the coal reserves in Velenje are

    exhausted. IGCC is a combined gassteam process with previous coal gasification. Theadvantage of this technology is in its possibility of using alternative fuels such aswood

    biomass,wasteoil, andmunicipalwaste. Italsohas theopportunityofusingnatural gas

    when Slovenia is connected to the South Stream pipeline from Russia. In this case, the

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    technology of the powerplant consists of gas turbines,which can benefit fromdifferenttypes of gaseous fuels. This newly built block could be integrated into the structure ofsustainable energy development, providing much needed energy until the technology ofalternativeenergysourceswillbefullydevelopedtomeetallenergyneedsinSlovenia.

    Krko,August2009

    AndrejPREDIN

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    10 JET

    Table of Contents /

    Kazalo

    Nuclearrenaissanceasaviablesolutionforreducinggreenhousegasestheenvironmentalimpactofdifferentenergytechnologies/Jedrska energija zmanjuje emisije toplogrednih plinov vplivi razlinih tehnologij za

    proizvodnjoelektrineenergijenaokolje

    Tomaagar,RobertBergant,SamoFrst................................................................................11

    Mathematicalmodelofthepowersupplysystemcontrol/Matematinimodelupravljanjaenergetskegasistema

    JanezUsenik...............................................................................................................................29

    The calculationof thermodynamicproperties forhydrochloric and copper compounds in ahydrogenproductionprocess/Izraun termodinaminih lastnosti v hidroklorovih in baker klorovih komponentah v procesu

    proizvodnjevodika

    JurijAvsec,GregF.Naterer,AndrejPredin...............................................................................47

    InvestmentsinrenewableenergysourcesandcasesofgoodpracticesoffiscalstimulationinEU/InvesticijevobnovljiveenergetskevireinprimeridobrepraksefiskalnihspodbudvEUMejraFesti.................................................................................................................................65

    Cavitationswirlattheentranceofcentrifugalpump/KavitacijskivrtinecnavstopuvradialnorpalkoAndrejPredin,BotjanGregorc,IgnacijoBilu..........................................................................85

    Instructionsforauthors..............................................................................................................99

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    JET 11

    JETVolume2(2009),p.p.1128

    Issue3,August2009

    http://www.fe.unimb.si/si/ejet/index.php

    NUCLEAR RENAISSANCE AS A VIABLE

    SOLUTION FOR REDUCING GREENHOUSE

    GASES THE ENVIRONMENTAL IMPACTOF DIFFERENT ENERGY TECHNOLOGIES

    JEDRSKA ENERGIJA ZMANJUJE EMISIJETOPLOGREDNIH PLINOV - VPLIVI

    RAZLINIH TEHNOLOGIJ ZAPROIZVODNJO ELEKTRINE ENERGIJE NA

    OKOLJE

    Tomaagar,1,RobertBergant2,SamoFrst3

    Keywords:emissions,environment,technology,electricityproduction

    Abstract

    Climate change is happening and represents one of the greatest environmental, social and

    economicthreats

    facing

    the

    planet.

    The

    Intergovernmental

    Panel

    on

    Climate

    Change

    (IPCC),

    an

    associationofscientistsfromallovertheworld,cametotheconclusionthatthemainreasonistheenhancedgreenhouseeffect.

    Tomaagar,PhD.,GENenergija,d.o.o.,Tel.:+386(7)4910132,Fax:+386(7)4901118,

    Emailaddress:[email protected] Tomaagar,PhD.,UniversityofMaribor, FacultyofEnergyTechnology, Tel.:+386 (7)62022102

    Robert

    Bergant,

    PhD.,

    GEN

    energija,

    d.o.o.,

    Tel.:

    +386

    (7)

    491

    0404,

    Fax:

    +386

    (7)

    490

    1118,

    Emailaddress:[email protected],GENenergija,d.o.o.,Tel.:+386(7)4910136,Fax:+386(7)4901118,

    Emailaddress:[email protected]

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    12 JET

    PhD.Tomaagar,PhD.RobertBergant,SamoFrst JETVol.2(2009) Issue3

    The production of electricity is, beside transportation, the most harmful contributor to the

    enhancedgreenhouseeffect.Unfortunately,themajorityofelectricityproduction isstillbased

    onacombustionoffossilfuels,e.g.coal,oilandgas.Renewablesourcessuchashydro,solaror

    wind

    are

    becoming

    increasingly

    preferable.

    Nuclear

    energy

    is

    also

    an

    important

    low

    carbon

    energy sourcewith insignificant impacton theenvironment. Itswholecycleemissionsareat

    leastaslowastheemissionsofabovementionedrenewablesources.Besidesitsenvironmental

    benefits,nuclearenergyhasalsoeconomical, spatial and socialadvantagesover someother

    renewablesources.

    The purpose of the article is to present integrated environmental impacts for different

    technologychainsused forelectricityproduction.Two separateand independent studiesare

    shown in this intention.A summaryofdifferent studies,madebyOrganization forEconomic

    CooperationandDevelopment (OECD),presents thecomparisonofenvironmental impactsof

    differenttechnologychainsfortheelectricityproductionsector,basedondatasuppliedbythe

    OECD organizations members. The study of the company GEN energija is focused on thecomparison of environmental impacts of different technology chains that are feasible for

    electricity production in Slovenia, i.e. technologies such as nuclear, coal, gas, different

    renewablesourcesandamixtureofrenewablesources,whichincludethehydro,biomass,wind

    andphotovoltaicproduction.

    Theevaluationoftheenvironmentalimpactsfordifferentenergytechnologiesisimplemented

    withinradius10kmoftheexistinglocationofNuklearnaelektrarnaKrko(NEK)site,inorderto

    evaluateandpresenttheenvironmentalconsequencesofdifferentelectricalpowerproducing

    energy technologies.Electricalpowerproduction from fourpotentialnuclear reactordesigns,

    imported coalfired power generation, combinedcycle gasfired generation, and renewable

    power generation sources, including hydroelectric generation, solar photovoltaic generation,windgeneration,biomasscogeneration,andgeothermalelectricgenerationareconsidered.

    Twoassumptionsforelectricalpowerproducingtechnologiesareaninstalledcapacityof1,100

    MWeanda90%BaseloadCapacityFactor.Therenewablesourcesareevaluatedasaresource

    mix (RESMix)andarenotcapable reaching the required90%BaseloadCapacityFactor. It is

    assumedtohaveacombined34%BaseloadCapacityFactoriftheevaluationregionisexpanded

    tothewholeofSlovenia.FortheRESMix,32%hydroelectricgeneration,36%windgeneration,

    32% biomass cogeneration,

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    JET 1

    NuclearRenaissanceasViableSolution forreducingGreenhouseGasesEnvironmentalImpactofdifferentEnergyTechnologies

    goriv, ki imajonajvejidoprinos kemisijam toplogrednihplinov. Zaradipotrebpo znievanjuspecifinihemisijnapomembnostizopetpridobivatudijedrskaenergija,kisodivnizkoogljinoproizvodnjoenergije.Pravtakosonjeniskupnivplivinaokoljeindrubougodnejialivsajtako

    ugodnikotvpliviobnovljivihvirov.

    Namen prispevkaje prikaz celostnih vplivov na okolje pri proizvodnji elektrine energije pri

    uporabi razlinih tehnologij.V tanamen staprikazanidve loeni inneodvisni tudiji, in sicerpovzetekrazlinihtudijmednarodneorganizacijezagospodarskosodelovanjeinrazvoj(OECD)in tudija podjetja GEN energija. Povzetek tudij organizacije OECD obravnava primerjavovplivov na okolje razlinih tehnolokih verig za pridobivanje elektrine energije na osnovipodatkov, ki jih organizaciji OECD posredujejo njene lanice. tudija GEN energije pa jeosredotoena na primerjavo vplivov na okolje obravnavanih tehnologij, ki so smiselne ter

    izvedljive za proizvodnjo elektrine energije v slovenskem prostoru in sicer jedrske,premogovne,plinske,obnovljivihvirov inmeaniceobnovljivihvirov,medkaterespadavodna,biomasna,vetrnainfotovoltainaproizvodnja.

    Oje obmoje prikazanih vplivov obsega 10km radij okoli obstojee lokacije NuklearneelektrarneKrko.Cilj tudijejeocenitev katera izmed tehnologijpredstavljanajnijocelostnoobremenitev okolja pri pasovni proizvodnji proizvodni elektrine energije na lokaciji ob

    obstojeiNuklearnielektrarniKrko.Zahtevizanovoproizvodnoenotostainstaliranaelektrinamo1100MWeinfaktorrazpololjivostienote90%.Ocenjenoje,dameanicaobnovljivihvirovnemore zadostiti osnovni zahtevi faktorja razpololjivosti 90% pri instalirani elektrinimoi1100MWe.Dosee levrednost34%,ob raziritvipredvidenegaobmojanacelotnoSlovenijo.Deleposameznetehnologijevmeaniciobnovljivihvirovpredstavlja32%vodna,36%vetrna,

    32%biomasna,

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    1 JET

    PhD.Tomaagar,PhD.RobertBergant,SamoFrst JETVol.2(2009) Issue3

    1 INTRODUCTION

    Climatechange

    is

    aresult

    of

    increasing

    greenhouse

    gas

    emissions

    and

    growing

    problem

    that

    requiresinterdisciplinarycooperationacrosstheworld.TheKyotoProtocolAlliancesignatories

    havetheobjectiveofa20%greenhouseemissionsreductionin2020,comparedto1986levels.

    The instrumentsforachievingthisaredifferentacrosscountries,but ingeneralallsignatories

    havetobecomelowcarbonsocietiesinallareas.Anespeciallysensitiveandimportantareain

    the transition to a lowcarbon society is the sectorof energyproduction,whichhas a large

    contributiontogreenhousegasemissions.Therefore,itisimportantforeachcountrytohavea

    detailedplanforthefurtherdevelopmentofthissector;thisalsohasan important impacton

    theeconomicperformanceofthecountry.Itisimportanttopursuedevelopmenttowardslow

    carbon,economicallyjustifiedandsustainabletechnologies.

    2 ELECTRICITY PRODUCTION IN SLOVENIA

    Theenergyproduction sectorcombinesheatproductionandelectricityproduction. In recent

    years, Slovenias electricityproductionhasbeen insufficient, since annual average electricity

    importhasreachedover20%.Suchhighinputlevelshavebeenreducingthecompetitivenessof

    the domestic economy; therefore, new investments in the modernization of the electricity

    productionaswellasexpansionofcurrentcapacityarenecessary.Amongthemost important

    technologies forSlovenianelectricityproductionarenuclear, coal,gas,hydroand renewable

    energysources

    technologies.

    Inaccordancewiththelegalcommitmentsregardingthereductionofgreenhousegasemissions

    setby theEU202020objectives,whichcall for20% fewerGHGemissions,20% lower final

    energy consumption and a 20% share of renewables in final energy consumption by 2020,

    production economy resources aims, greater economic competitiveness and sustainable

    developmentobjectives,andallproductiontechnologiesshouldbecomparedunderthesame

    principle before the decision for a particular technology in the process of extending the

    electricityproductioncapacityshouldbemade.Thecomparisonshouldbebasedonthesame

    basicplatformaswellasontheevaluationofindividualtechnologies.

    Slovenia

    has

    a

    similar

    procedure,

    as

    the

    one

    mentioned

    above,

    in

    the

    process

    of

    spatial

    planning

    called a strategic/comprehensive environmental impact assessment and an environmental

    impactassessment.Thesetwoprocessesarenotacomparisonwithothertechnologiesandthe

    choiceof theoptimal solution,butonlyevaluationof theenvironmentalacceptabilityof the

    individual plans without intervention on site. The Republic of Slovenia therefore has no

    legislation for the comparison of technologies thatwould serve foroptimal decisions in the

    processofproductioncapacityexpansion.

    Similar comparison studiesaremore common abroad.One such stuywas completedby the

    OrganizationforEconomicCooperationandDevelopment(OECD),whichhas largestdatabase

    for the comparison of technologies based on energy production factors. The analyses

    performedby

    the

    OECD

    were

    based

    on

    current

    actual

    data,

    delivered

    by

    countries

    all

    around

    theworld.Therefore,wewanttopresentthemostimportantresultsofsomeOECDanalysisas

    wellasourstudyofenvironmental impactsofdifferentenergy technologyoptions,enhanced

    withanalysisanddata,basedonglobalscaleexpertise.

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    JET 1

    NuclearRenaissanceasViableSolution forreducingGreenhouseGasesEnvironmentalImpactofdifferentEnergyTechnologies

    GEN energija is an energy company thatwants to play an active role in the new cycle of

    investment in new electricity production capacity in Slovenia. To enhanceGENs technology

    decision with substantiated facts, the study of environmental impacts of different energy

    technologyoptions

    for

    electricity

    production

    in

    Slovenia

    [1]

    was

    ordered

    from

    an

    internationally

    recognized engineering firm, the Washington Group International (a division of URS

    Corporation),whichhasastrongteamofenvironmentalexperts.

    3 RESULTS OF OECDs TECHNOLOGY COMPARISONS STUDIES

    TheOrganization forEconomicCooperationandDevelopment (OECD)made thecomparison

    analysesofdifferenttechnologychains[2].Thesestudieswerebasedon informationsupplied

    by the organizations individualmember states, aswell as by countries that are not OECD

    members.Thestudies included theenvironmental,socialandeconomicaspectsof theentireenergychainfromthebeggingtotheend(lifecycleassessmentLCA).

    Sciencebased, industrial, international lifecycleassessment (LCA)and lifecyclemanagement

    (LCM)datafromallovertheworldcanbefoundonhttp://www.ecoinvent.org/.Theecoinvent

    Centre is theworld's leading supplierof consistent and transparent life cycle inventory (LCI)

    dataofknownquality.TheresultspresentedbelowarebasedonreportsofDonesetal.[46].

    Environmental (greenhouse gas emissions, SOX, NOX, nonradioactive waste, land use and

    accidentrisks),social(humanhealthimpacts)andeconomicindicators(useofenergyandnon

    energeticresources)arepresented.

    3.1 Greenhouse gas emissions

    Greenhousegasemissionshaveaglobalimpactontheenvironment,withamajorroleinglobal

    warming and climate change. Figure1 shows a comparisonof greenhouse gasemissions for

    eachelectricityproductiontechnologychain.

    Foreachtechnology,theaveragedatavalueispresentedtogethernetmaximumandminimum

    values.Themaxandminvaluesarealsolabeledwithcountrycodes,indicatingtheoriginofthe

    data.

    Emissions are expressed in kgCO2 equivalent per unit of generated energy. Lignite has the

    highestemissions

    in

    the

    UCTE

    (The

    Union

    for

    the

    Co

    ordination

    of

    Transmission

    of

    Electricity)

    average, slightly above 1.2 kgCO2eq./kWh; coal has a slightly lower level, with the UCTE

    average of around 1.07 kgCO2eq./kWh. The chain of natural gas has the lowest level of

    emissionsoffossilsystemswithUCTEaverageslightlyabove0.6kgCO2eq./kWhandaround0.4

    kgCO2eq./kWh for cogeneration.Greenhouse gas emissions from the nuclear chain and the

    renewableenergy sources chains are twoordersofmagnitudebelow theemissionsof fossil

    fuelschains.TheUCTEaverage fornuclear isabout8gofCO2eq./kWh,5gCO2eq./kWh for

    hydro,11gCO2eq./kWhforcostalwindturbines,14gCO2eq./kWhforoffshorewindturbines,

    60gCO2eq./kWhforPV(photovoltaics) [7]and100gCO2eq./kWhforwoodcogeneration.

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    PhD.Tomaagar,PhD.RobertBergant,SamoFrst JETVol.2(2009) Issue3

    Figure1:CO2equivalentgreenhousegasemissionsforeachelectricityproductiontechnologychains

    3.2 Other atmospheric emissions

    Whilethegreenhousegasemissionshaveimpactsonglobalwarmingandclimatechange,SOX,

    andNOXhavemoreregionalandlocalimpacts.Inaddition,thesepollutantsareimportantalso

    fromregularpointofview.ThereareSEVESOEUandnationalregulationsandEnvironmental

    protectionActlimitingtheSOXandNOXemissions.

    SO2emissionsaredominatedbythedirectemissionsfrompowerplants.Thelevelofemissions

    dependsonthesulfurcontentoffuelsandtheemissioncontrolcriteria..AsshowninFigure2

    brown

    coal

    and

    oil,

    with

    a

    UCTE

    average

    of

    around

    7

    g/kWh,

    have

    the

    highest

    level

    of

    SO2

    emissions.HardcoalhasaUCTEaverageofabout3g/kWh,whilethechainofnaturalgashasa

    UCTEaverageofabout0.2g/kWhemissions,whichistheminimumbetweenthechainsoffossil

    fuels.TherateofSO2emissions inthenuclearchainandtherenewableenergysourceschains

    aremorethantwoordersofmagnitudebelowtheemissionsoffossilfuelschains.Hydroand

    windhavethelowestlevelofSO2emissionsamongrenewableenergysourceschains.

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    Figure2:SO2emissionsforeachelectricityproductiontechnologychains

    Oilhas thehighest levelofNOXemissionsofall theenergy chain,with theUCTE averageat

    around2.8

    g/kWh

    (see

    Figure

    3).

    Levels

    of

    NOXemissions fromcoalchainsareslightly lower,

    with theUCTEaverageofaround2.2g/kWh.Thechainofnaturalgashas the lowest levelof

    NOXemissionsamongfossilsystemswithaUCTEaverageofaround0.7g/kWh.ThelevelofNOX

    emissionsfornuclear,hydroandwindtechnologyisuptotwoordersofmagnitudelowerthan

    therateoffossilfuelsNOXemissions.

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    Figure3:NOxemissionsforeachelectricityproductiontechnologychains

    3.3 Non-radioactive waste

    Figure4:Productionofnonradioactivewastefordifferentenergychains

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    ProductionofnonradioactivewastefordifferentenergychainsisshowninFigure4.Hardcoal

    and lignite power chains produce the largest quantities of nonradioactive waste with UCTE

    averagesofaround1.18kg/kWh.Withinthelignitechain,amajorcontributionisashproduced

    duringpower

    plant

    operation,

    while

    within

    hard

    coal

    chains

    asubstantial

    proportion

    of

    the

    wastecomesfromexcavation.Thenaturalgasandnuclearchainsproduceaminimumquantity

    ofnonradioactivewaste.Theamountofnonradioactivewasteinhydroandwindchainsistwo

    ordersofmagnitudehigherthanforthenuclearchain.

    3.4 Land use

    Landuse, shown inFigure5, ismeasured inm2/kWhand refers to areas which are modified

    from natural or primary habitat to different habitat states as a result of human intervention

    insidethe

    whole

    energy

    chain.

    Figure5:LandusefordifferentenergychainsDue to the forestryand logging thatarerequired for theuseofbiomass,woodcogeneration

    requires the largest land use, followed by coal and oil energy chains. Exploitation and

    productionofoil,aswellastheextractionofhardcoal,requireconsiderablespace.

    3.5 Accident risks

    The data are derived from a comprehensive severe accidents databases, ENSAD (the Energy

    relatedSevere

    Accident

    Database),

    with

    an

    emphasis

    on

    the

    energy

    sector.

    Databases

    enable

    a

    comprehensiveanalysisofaccidentsrisks,whicharenotlimitedtoelectricitypowerplantsbut

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    covertheentireenergychain, includingexploration,extraction,processing,storage,transport

    andwastemanagement.

    ENSAD currently contains 18,400 accidents, of which approximately 89% occurred between

    1969

    and

    2000.

    Human

    causes

    of

    accidents

    represent

    70%

    of

    all

    accidents,

    while

    natural

    disastersrepresent30%.Allaccidentsrelatedtoenergyrepresenting35%ofallaccidentsand

    50%ofhumancausedaccidents.Among theenergyassociatedaccidents, theshareofsevere

    accidentsis49%,amongwhich67%accidentsarewithfiveormorefatalities.Accidentsthatare

    not related to energy and natural disasters have secondary importance within ENSAD. More

    detaileddatacanbeseeninTable1.

    Table1:ENSADreportoverviewforaccidentswithatleastfivefatalitiesforperiodfrom1969to2000

    Energy OECD EU15 nonOECD

    chain

    Accidents Fatalities

    Accidents Fatalities Accidents Fatalities

    Coal 75 2,259 11 234 102

    1,044(a)

    4,83118,017

    (a)

    Oil 165 3,789 58 1,141 232 16,494

    Naturalgas 80 978 24 229 45 1,000LPG 59 1,905 19 515 46 2,016

    Hydro 1 14 0 0 10 29,924(b)

    a)Firstlinewithout China,secondlinewithChina

    b)BanqiaoandShimantandamfailurestogethercaused26,000fatalities

    Figure6:SevereaccidentsindicatorsforOECDandnonOECDcountriesforperiodfrom1969to2000

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    ChinahasexceptionalaccidentsstatisticforhydroastheresultoftheBanqiaoandShimantan

    dam failures,whichoccurred in1975.Bothdamswerebrokenasaresultofconstructionand

    engineeringerrors,whichbecamecriticalduringahugefloodin1975.Asaresultofthesetwo

    damfailures,

    62

    dams

    were

    destroyed

    flooding

    an

    area

    of

    55

    km

    by

    15

    km.

    Some

    reports

    indicatethetotalnumbersoffatalitiesaresomewherebetween90,000and230,000[3].

    Figure6representsthefatalitiesnormalizedtotheunitofenergyproducedperGWeyear.The

    highestvalueoffatalitieswascausedbyLPGenergychain,duetothedangerofhandlingLPG.

    ThesecondhighestvalueiswiththehydroenergychainduetotheabovementionedBanqiao

    andShimantandamfailures.Thecoalenergychainisonthirdplaceduetotheminingprocess,

    whichisespeciallydangerousinChina,wheresafetyisatlowlevel.ValuesforOECDandEU15

    memberstatesarealmostthesamefortheselectedtechnologychainduetothehighersafety

    culturelevel.

    3.6 Human health impacts from normal operation

    Effectsonhumanhealth inrelationtothenormaloperationcanberepresentedbymortality.

    Mortalityisdefinedasareductionofexpectationsoflife,expressedintermsofyearsoflifelost

    (YOLL). The consequences of diseases could be evaluated, but it is difficult to combine in a

    completelyobjectivemanner,becausetheendresult,yearsoflifelost,andpopulationvalues,

    providedbymonetaryrelationschangedramaticallydependingon localconditions,densityof

    thepopulation,theprospectof lifeexpectancyandthemedicalassistancethat isavailablefor

    theaffectedpopulation.Figure7showsanexampleofmortalitythatistheresultofemissions

    ofmajorpollutants,specifictothecurrentGermanenergychains,alsotakingintoaccountthe

    radioactiveemissions

    [8].

    The

    methodology

    for

    assessment

    of

    health

    impacts

    was

    developed

    within the European ExternE project and later revised by Friedrich et al. [9] and Bickel and

    Friedrich[10].

    Figure7:MortalityassociatedwithnormaloperationofGermanenergychainsintheyear2000

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    Nuclear,windandhydroenergychainshavelowmortalityinrelationtotheirnormaloperation.

    Themortality fornatural gas and solar PV chainsare comparable. Fossil systemsother than

    natural gas indicate a greater impact than other options.Mortality due to air pollution is

    strongly

    dependent

    on

    the

    location,

    which

    determines

    the

    number

    of

    people

    affected

    by

    the

    emissionsand the technology,whichwilldetermine thequantityofemissions.The figure for

    YOLLpertonofSO2releasedinChinaisonaveragealmostseventimeshigherthantheaverage

    of the EuropeanUnion,mainly due to drastic differences in population density around the

    plants.

    3.7 Use of energy resources

    Fossilresourceshavebeenselectedasan indicatorofenergyproductuseduetotheir lackof

    stock andusefulnesswithinother sectors.Thishas adirect impacton the longtermenergy

    sustainability,ifwe

    intend

    to

    preserve

    resources

    for

    chemical

    and

    other

    uses,

    and

    not

    just

    for

    energy.

    Theconsumptionoffossilfuelsforelectricityproductiondifferentchainsaregiven inFigure8

    andcoversthememberstatesofUCTEandsomeotherEuropeancountries.

    Figure8:RequirementsoffossilresourcesfordifferentenergychainsConsumptionis,ofcourse,muchgreaterinthefossils,coal,gasandoilchains,thaninthecase

    ofnuclearandrenewableenergysourceschains.Chainswithcombinedgaspowerplantshave

    the lowest consumption of fossil chains, which is expected due to their effectiveness.

    Renewableenergysourcesandnuclearchainsindirectlyusefossilfuelsforheatandelectricity

    consumptionwithintheirchains.Hydroenergyhasthelowestconsumptionoffossilfuels.

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    3.8 Use of non-energy resources

    Usageofothernonrenewableresourcessuchasfossilfuelsanduraniumisthemeasurementof

    electricityproduction

    impact

    to

    the

    environment,

    and

    therefore

    is

    included

    in

    economic

    indicators.Copperwasselectedasthereferencematerialforthe limitedmetalresources,but

    the consumption of othermaterials could also be used. Figure 9 shows the comparison of

    copperneedsforvariouselectricitytypesofproduction inUCTEcountries.SolarpanelsorPV

    showsthehighestneedforcopper,whichexceededtheneedsoftheotherchainsbyafactorof

    five; solar is followed by the wind energy chain. Chains of fossil fuels, nuclear, and wood

    cogenerationhavecomparableneedsforcopper,whicharelowerbyafactorof10comparedto

    PV.Hydroenergyshowsthelowestrequirementsforcopper.

    Figure9:Requirementsofcopperfordifferentenergychains

    4 ENVIRONMENTAL IMPACTS OF DIFFERENT ENERGYTECHNOLOGY OPTIONS FOR ELECTRICITY PRODUCTION INSLOVENIA

    Sloveniaisinthedecisionmakingprocessforitsfutureenergyproductionsectordevelopment.

    Thedecisionforaspecifictechnologymustbebasedonfactsderivedbyenvironmentalimpact

    comparisons liketheOECDstudies,as indicatedabove.Therefore,GENenergijahasordereda

    widened environmental impact assessment study with comparisons of different technology

    optionsforelectricityproductioninSlovenia.

    Thisstudy

    was

    done

    by

    URSs

    team

    of

    environmental

    experts.

    The

    basic

    position

    was

    the

    technology isavailable inSloveniaand, ifpossibletobe locatedwitharangeof10kmaround

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    Table2:Summaryofenergytechnologyimpacts

    The summary table (Table3) of the sitespecificdecision factorswas used for assessing and

    ranking the relative feasibilityanddesirabilityof the fourprimaryenergy technologyoptions

    evaluatedin

    the

    study.

    The summary table decision factors are land requirements per kWh, green house gases per

    kWh,energysupplysecurity,baseloadcapacity factor,ability to locate in regionof influence,

    cost per kWh, existing infrastructure, uncertainty risk, economictechnology feasibility,

    aggregateenvironmentalimpacts.Allthesedecisionfactorswereevaluatedaccordingtoseven

    differentrankings:Xexcellent,Ggood,Ffair,Ppoor,Uundesirable,Nnotavailableor

    notapplicableandSwherewassourcedepended.

    Nuclear technology is evaluated as the most optimal technology for the expansion of

    productioncapacities

    in

    Slovenia.

    Renewable energy sources, whose potential in Slovenia is already heavily utilizing, are

    estimatedtobe fair toundesirableandcanserveonlyascomplementary technologiestothe

    basicscenariofortheexpansionofproductioncapacity.

    Nuclear

    ImportedCoa

    l

    NaturalGas

    CombinedCycle

    Hydroelectric

    Solar

    (Photovoltaic)

    W

    ind

    Biomass

    Cogeneration

    Geothermal

    ZeroOption

    RESMixOption

    *

    Climate B E D A-B B-C C C C X C

    Ai r B D D A A B C B A C

    Surface Water and Groundwater C C C B A A C B B C

    Noise C B B B B C B B A C

    Ground and Agricultural Surfaces B C-D C A A-D C C-D B-D B D

    Landscape C C C A A-B C C C B C

    Nature and Natural Areas C B-D B C-D B B-D B-D B B D

    Waste M anagement System C D A A A A C A A C

    Human and Environmental Health Risks C B B A A-B D-E B B B E

    Ionizing Radiation C C-D B A-B A A A A-B X B

    Inhabi tants and their Environment A-B E C-D A D-E A C-D A D-E A-C

    Cumulations with other Regional Projects B D C A A-D B-D B-D C-D A D

    Cultural Heritage B C B B B B B B B B

    Protected Areas and Zones B C B D B D B B X D

    Integrated Ranking C D D C C D D C C D

    Features

    Impacted

    Summary of Energy Technology Impacts

    Energy Technologies

    A = No Impac t/ positive impact; B = Insubstantial impact; C = In substantial impacts with mitigation ;

    D = Substantial impact; E = Destructive impact; X = Establishing impact not possible

    * RES Mix is 32% hydro, 36% wind, 32% biomass

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    Table3:Summaryofdecisionfactorsfortechnologyselection

    6 CONCLUSION

    Thedecisionmakingprocessforshortand longtermenergyfuturesolutionsshouldbebased

    onsolidenvironmentalimpactscomparisons.

    GENenergijaordered thepresentedcomparative study to substantiate itsbusinesspurposes

    andthe

    decisions,

    but

    the

    main

    purpose

    is

    to

    convince

    all

    who

    are

    involved

    in

    the

    decision

    makingprocessesofhow the futuredevelopmentofenergy for Slovenia shouldentitled the

    environmental,economicandsustainablepointofview.

    Nuclear technology is at the top of the environmental acceptability on the global scale, as

    shownbytheOECDstudies,aswell locally,whichhasshownbytheURSGENstudy.Froman

    environmental point of view, nuclear energy is one of the optimal technology choices for

    Slovenia,whileincombinationwithotherdecisionmakingfactorsitbecomesthemostoptimal.

    Itisalsotheonlybaseloadelectricityproducer,whoseinstalledpowercanbeincreasedalmost

    without any impact to the environment, as evidencedby the study. In addition to baseload

    electricityproduction,newnuclearpowerplantsarealsocapableofoperating in load follow

    production.By

    increasing

    the

    share

    of

    nuclear

    energy

    in

    final

    energy

    consumption,

    Slovenia

    could also greatly reduce greenhouse gas emissions and could achieve the EU and national

    targetsforreducingsuchemissions.

    If Slovenia wants to stay environmentally conscious, if wants to keep or even increase the

    competitiveness of the economy and meet the requirements of sustainable development,

    nuclearenergyistheoptimalsolutionforthefuture.

    References

    [1] URS Washington Group: Preliminary Report on Environmental Impacts of Different

    EnergyTechnologyOptionsforSlovenia,April2009,URS

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    PhD.Tomaagar,PhD.RobertBergant,SamoFrst JETVol.2(2009) Issue3

    [2] OECDNuclearEnergyAgency:NuclearEnergyRisksandBenefits,2007,OECDNEA

    [3] http://en.wikipedia.org/wiki/Banqiao_Dam

    [4] DonesR.,BauerC.,BolligerR.,BurgerB.,FaistEmmeneggerM.,FrischknechtR.,HeckT.,

    JungbluthN.andRderA.,2004a,LifeCycle InventoriesofEnergySystems:Resultsfor

    CurrentSystems inSwitzerlandandotherUCTECountries.Final reportecoinvent2000

    No.5.PaulScherrerInstitut/Villigen,SwissCentreforLifeCycleInventories/Duebendorf,

    Switzerland.

    [5] DonesR.,BauerC.,BolligerR.,BurgerB.,FaistEmmeneggerM.,FrischknechtR.,HeckT.,

    JungbluthN.andRderA.,2004b,SachbilanzenvonEnergiesystemen:Grundlagen fr

    den kologischen Vergleich von Energiesystemen und den Einbezug von

    EnergiesystemeninkobilanzenfrdieSchweiz.Finalreportecoinvent2000No.6.Paul

    Scherrer Institut/Villigen, Swiss Centre for Life Cycle Inventories/Duebendorf,

    Switzerland.

    [6] DonesR.,ZhouX.,TianC.,2003,LifeCycleAssessment.In:EliassonB.andLeeY.Y.(Eds):Integrated Assessment of Sustainable Energy Systems in China The China Energy

    Technology Program, Book Series: Alliance forGlobal Sustainability Series: Volume 4,

    KluwerAcademicPublishers,Dordrecht/Boston/London(2003)319444.(Bookincl.DVD,

    Hardbound ISBN 1402011989, Paperback ISBN 1402011997). Available at:

    http://www.springeronline.com/sgw/cda/frontpage/0,11855,5403567233707785

    0,00.html

    [7] http://re.jrc.cec.eu.int/pvgis/pv/imaps/imaps.htm

    [8]

    HirschbergS.,

    Dones

    R.,

    Heck

    T.,

    Burgherr

    P.,

    Schenler

    W.

    and

    Bauer

    C.,

    2004a,

    SustainabilityofElectricitySupplyTechnologiesunderGermanConditions:AComparativeEvaluation,PSIreportNo.0415PaulScherrerInstitut,Villigen,Switzerland.

    [9] FriedrichR.,MarkandyaA.,HuntA.,OrtizR.A.,DesaiguesB.BounmyK.,AmiD.,Masson

    S.,RablA.,SantoniL.,SalomonM.A.AlberiniA.,ScarpaR.,KrupnickA.,DeNockerL.,

    Vermoote S.,Heck T., Bachmann T.M., Panis L.I., Torfs R., Burgherr P.,Hirschberg S.,

    PreissP.,GressmannA.,DrosteFrankeB.,2004,NewElements for theAssessmentof

    External Costs from Energy Technologies (NewExt). Final Report to the European

    Commission, DG Research, Technological Development and Demonstration (RTD),

    September 2004. http://www.ier.uni

    stuttgart.de/forschung/projektwebsites/newext/newext_final.pdf

    [10] Bickel,P.andFriedrich,R. (Editors),2005,ExternEExternalitiesofEnergyMethodology2005 Update. European Commission, Directorate General for Research, SustainableEnergySystems,EUR21951.

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    JETVolume2(2009),p.p.2946

    Issue3,August2009

    http://www.fe.unimb.si/si/ejet/index.php

    MATHEMATICAL MODEL OF THE POWER

    SUPPLY SYSTEM CONTROL

    MATEMATINI MODEL UPRAVLJANJAENERGETSKEGA SISTEMA

    JanezUSENIK

    Keywords:powersupplysystem,control,optimalenergycapacities,Laplacetransform,

    fuzzylogic;

    Abstract

    Inthisarticle,asimplemathematicalmodelofacontinuousstochasticpowersupplysystem isdescribed. Some analytical approaches have been developed to describe the influence of

    productionand stock, i.e.additionalcapacitiesonahierarchical spatialpatternanddemand.

    UsingtheLaplacetransform, it ispossibletosolvethesystemofdifferentialequations,which

    arerepresentedwiththecontinuousmodel.Duetothestochasticnatureofsysteminputs,the

    optimality criteria with the Wiener filter are satisfied. The inverse Laplace transform is

    calculated with residues in the complex space. Furthermore, an interesting and efficient

    approachwithfuzzylogicisused,whichispresentedattheendofthisarticle.

    Povzetek

    V lankujepredstavljenmatematinimodelupravljanjazveznega stohastinegaenergetskega

    sistema.Razvitisonekaterianalitinipristopi,skaterimiopiemomedsebojnivplivproizvodnje

    terzalog,v taknihsistemihso tododatnekapacitete,nahiearhinoporazdeljenoprostorsko

    dogajanje/porabooziromapovpraevanje.ZuporaboLaplaceovetransformacijereimosistem

    diferencialnihenab,kiopisujejodinamikozveznegasistema.Pogojuoptimalnostilahkozaradi

    stohastinih vhodov sistema zadostimo z uporabo Wienerjevega filtra. Inverzno Laplaceovo

    transformacijoopravimozuporaboresiduov.Vnadaljevanju lankaprikaemoekot izjemno

    zanimiv in zlasti zelo uinkovit nain pristopa k reevanju taknega problema tudi monost

    uporabemehkelogike.

    Corresponding author: Prof. JanezUSENIK, PhD.,University ofMaribor, Faculty of Energy

    Technology,tel.+38631751203,Fax:+38676202222,Mailingaddress:Hoevarjevtrg1,8270

    Krko,emailaddress:[email protected]

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    JanezUsenik JETVol.2(2009) Issue3

    1 DEFINING THE PROBLEM

    Every model of optimal control is determined by a system, input variables and the

    optimality

    criterion

    function.

    The

    system

    represents

    a

    regulation

    circle,

    which

    generally

    consists of a regulator, a control process, a feedback loop, and input and output

    information (DiStefano, 1987). In this article, we will only discuss linear dynamic

    stationary continuous systems (Usenik et all, 2008). The optimality criterion is the

    standardagainstwhichthecontrolqualityisevaluated.The termcontrolqualitymeans

    optimalandsynchronizedbalancingofplannedandactualoutputfunctions.

    Let us consider aproductionmodel in a linear stationarydynamic system inwhich the

    input variables indicate the demand for products manufactured by a company. These

    variables, i.e. the demand in this case, can be a onedimensional ormultidimensional

    vector functionon the onehandand deterministic, stochasticor fuzzyon the other. In

    thisarticle,

    stochastic

    variables

    and

    an

    outline

    of

    afuzzy

    approach

    are

    presented.

    Let ustakeastationaryrandomprocessXwiththe knownmathematicalexpectationE(X)

    and autocorrelationRXX(t) asthe demand inastochasticsituationthatshouldbemet, if

    possible,bythe currentproduction.The differencebetweenthe currentproductionand

    demand isthe inputfunctionfor the controlprocess,the outputfunctionofwhich isthe

    current stock/additional capacities.When the difference ispositive, the surpluswillbe

    stockedand when it isnegative,the demandwillalsobecoveredfromstock.Ofcourse,

    in the caseofpower supplywedonot have stock in the usual sense (suchas in caror

    computeretc.);energycannotbeproducedinadvanceforaknowncustomernorcanstockbe

    builtupforunknowncustomers.Thedemandofenergyservicesisneitheruniformintimenor

    knownin

    advance.

    It

    varies,

    has

    its

    ups

    (peaks)

    and

    downs

    (minima)

    and

    it

    can

    only

    be

    met

    by

    installingandactivatingadditionalpropertechnologicalcapacities.Becauseofthis,thefunction

    of stock in the energy supply process belongs to all the additional technological

    potential/capacities, largeenough tomeetperiodsof extrademand. Thedemandofenergy

    servicesisnotgivenandpreciselyknowninadvance.Withmarketresearch,wecanonlylearn

    about theprobabilityofourspecificexpectationsof intensityofdemand.Thedemand isnot

    givenwithexplicitlyexpressedmathematicalfunction;weonlyknowtheshapeandtypeofthe

    familyof functions.Demand is,according to these facts,a randomprocess forwhichall the

    statisticalindicatorsareknown.

    Thesystem inputrepresentsthedemandfortheproducts/services thatagivensubjectoffers.

    Let demand be a stationary random process with two known statistical characteristics:

    mathematical expectation and autocorrelation function (Usenik, 2001). Any given demand

    should be met with current production. The difference between the current capacity of

    production/services and demand is the input function for the object of control. The output

    function measures the amount of unsatisfied costumers or unsatisfied demand in general.

    When thisdifference ispositive, i.e.when thepowersupplycapacityexceeds thedemand,a

    surplus of energy will be made. When the difference is negative, i.e. when the demand

    surpassesthecapacities,extracapacitieswillhavetobeaddedor,iftheyarenotenough,extra

    purchasing fromoutsidewillhave tobedone.Otherwise, therewillbedelays,queuesetc. In

    thenewcycle,therewillbeasystemregulator,whichwillcontainallthenecessarydataabout

    thetrue

    state

    and

    which

    will,

    according

    to

    given

    demand,

    provide

    basic

    information

    for

    the

    productionprocess.Inthisway,theregulationcircuitisclosed(Fig.1).Withoptimalcontrolwewill understand the situation in which all costumers are satisfied with the minimum

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    Mathematicalmodelofthepowersupplysystemcontrol

    involvement of additional facilities. On the basis of the described regulation circuit, we can

    establishamathematicalmodelofpowersupplycontrol,i.e.asystemofdifferentialequations

    forcontinuoussystems(Bogataj,Usenik,2005)inoursituation.

    Figure1:Regulationcircuitofthepowersupplysystem

    The task istodeterminethe optimumproductionand stock/capacities,sothatthe total

    costwillbeaslow aspossible.

    2 EQUATIONS OF THE MODEL

    Notationsfor 0t areasfollows:

    Z t additionalcapacities(stocks)atagiventimet,

    u t productionattimet,

    d t demandforproductattimet,

    leadtime

    Let Z t , u t and d t bestationarycontinuousstationaryrandomvariables/functions; theyarecharacteristicsofcontinuousstationaryrandomprocess.

    Nowthe

    system

    will

    be

    modelled

    with

    the

    known

    equations:

    Z t v t d t (2.1)

    v t u t (2.2)

    0

    t

    u t G Z t d (2.3)

    In the equation (03) the function G t is the weight of the regulation that must be

    determinedat

    optimum

    control,

    so

    that

    the

    criterion

    of

    minimum

    total

    cost

    is

    satisfied.

    The parameter ,namedleadtime, isthe timeperiodneededtoactivatethe additionalcapacities inthe powersupplyprocess.Weusedarealsituation inwhichany goodscan

    demand powerstation capacity,potential

    production

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    be sold to the customeronly from the storehouseof finishedgoods,becauseonly in

    this case can the information flow of a company be updated and in accordance with

    legislation.

    Assumingthat

    the

    input

    variable

    demand

    is

    astationary

    random

    process,

    we

    can

    also

    considerproduction and stock/additional capacities tobe stationary randomprocesses

    for reasonsofthe linearityofthe system.Let usconsiderthe functions Z t , u t and d t

    tobecontinuousstationaryrandomprocesses.

    Let us express the total cost, the minimum ofwhichwe are trying to define,with the

    mathematicalexpectationofthe squareofrandomvariables Z t and u t :

    2 2Z uQ t K E Z t K E u t (2.4)

    In(2.4)

    ZKand

    uK arepositive

    constant

    factors,

    attributing

    greater

    or

    smaller

    weight

    to

    individualcosts.Both factorshavebeendeterminedempirically for the productand are

    thereforeinthe separateplant(Usenik,Bogataj,2005).

    Equations (2.1)(2.4)representa linearmodelofcontrol inwhichwehave todetermine

    the minimumofthe meansquareerror,ifbymeansofaparallelshiftwecausethe ideal

    quantitytoequalzero.

    Functionsofthesystemare normallytransferred intothe complexareabymeansofthe

    Laplace transform. Let be L Laplace operator and Z s , D s , u s , v s Laplacetransforms:

    Z s Z t

    D s d t

    U s u t

    V s v( t )

    L

    L

    L

    L

    Whennow the Laplacetransform isperformedon the functionsofthe system (01)(03),

    weobtainthe expressions:

    1

    Z s v s d s

    s

    (2.5)

    sv s e u s (2.6)

    u s G s Z s (2.7)

    nthe simplifiedversiontheexpressionsare defined,asfollows

    pD s G s d s (2.8)

    fV s G s u s (2.9)

    f f pG s G s G s (2.10)

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    1

    f

    G sW s

    G s G s

    (2.11)

    wemaydrawthe flowchartinan usualcascadeform(Figure2).

    Figure2:The cascadeflowchart

    The function (2.4), the minimum of which we are trying to determine, is written in

    accordancewiththedefinition ofthe autocorrelationinthe followingform:

    0 0 Z ZZ u uuQ K R K R

    or,divided

    by

    0ZK

    2

    2

    0 0 ZZ uu

    Z

    u

    Z

    P R A R

    QP

    K

    KA

    K

    (2.12)

    FromFigure2wecansee:

    u s W s D s (2.13)

    1fZ s W s G s D s (2.14)

    Spectraldensitiesfrom ZZR t and uuR t are asfollows:

    0

    1 1st

    ZZ ZZ ZZ f f DDs R t R t e dt W s G s W s G s s

    L (2.15)

    0

    st

    uu uu uu DDs R t R t e dt W s W s s

    L (2.16)

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    Bothequations(2.15)(2.16)are transformedinthe realtimespaceand insertedintothe

    equation(2.12):

    2

    1 1 2 1 2 2

    1 1 2 2 3 3 4 1 2 3 4 4

    2

    1 1 2 1 2 2

    0 0

    0 2

    ZZ uu

    DD f DD

    f f DD

    DD

    P R A R

    R W t dt G t R t t dt

    W t dt G t dt W t dt G t R t t t t dt

    A W t dt W t R t t dt

    (2.17)

    Weare looking for the minimumof the equation (2.17).Thisoptimum isobtainedwith

    thevariation

    calculus:

    optW t W t W t (2.18)

    In(2.18),thefunction W t isavariationofthe function W t , representsavariation

    parameterand optW t isthe optimalsolutionof(2.18).Function 0W t for 0t .From

    (2.17)and(2.18),theWienerHopfequationisderived

    2

    3 3 2 2 4 1 2 3 4 4 1 3

    2 1 2 2 10 for 0

    opt f f DD DD

    f DD

    W t dt G t dt G t R t t t t dt A R t t

    G t R t t dt t

    (2.19)

    The second variation 2

    2

    d P

    d

    is obviously positive for every 1 0t and the solution

    optW t ofthe equation(2.19)istheminimum.

    3 SOLUTION OF THE WIENER-HOPF EQUATION

    The WienerHopf equation (2.19) is solved by the spectral factorisation method

    (Schneeweiss,1971).From (2.19) theWienerHopfequation isobtained inthe following

    form:

    0 for ,optW t d t t

    (3.1)

    Thisequation isanordinary integralequationof the firstorder,whichcan besolvedby

    theFourier/Laplace

    transform:

    0optW s s s

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    andfinally

    opt

    sW s

    s

    (3.2)

    The function s has its zeros(i.e.polesof(3.2))onlyonthe leftsideofthecomplex

    plane (s1,s2, s3 inFigure3).Similarly,the function s has itszeroson the rightsideofthecomplexplane(s4,s5, s6inFigure3).

    Figure3:Polesofthefunction(21)

    Alsothefunction s has itspolesonly inthe lefthalfcomplexplane,whereas s onlyintherighthalfcomplexplane.

    The optimalsolution for the cascadeoperator isobtained in formaldesignby (3.2).The

    functionsinthe formula(3.2)are definedwithexpressionsinthe Laplaceform:

    2 f DD

    f f

    G s ss

    G s G s A

    2 f f DDs G s G s A s

    4 THE INVERSE LAPLACE TRANSFORM AND RESIDUES

    The Laplace transform method solves differential equations and corresponding initial and

    boundary value problems. The solution of the subsidiary equation in the complex plane is

    transformedback to realplane to obtain the solutionof the given problem. In theend,we

    determinethe

    inverse

    transform -1 f t F sL , i.e. the solution of the problem. This is

    generally themostdifficultstep,and in itwemayuse the tableofLaplace transformsor the

    residues(Kreyszig,1999).

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    The purpose of the residue integrationmethod is the evaluation of integrals C

    f s ds ,

    takenaroundasimpleclosedpathC.Iff(s)isanalyticeverywhereonCand insideC, such

    an integralequalszero: 0C

    f s ds .Iff(s) has a singularity at the point

    0s s inside C, but is otherwise analytic on C and

    insideC,the function f(s)assumestheLaurentseries:

    0

    0 10

    2 3 31 2

    0 1 0 2 0 3 0 2 3

    0 0 0

    k k

    k kk k

    b f s a s s

    s s

    bb ba a s s a s s a s s

    s s s s s s

    (4.1)

    thatconvergesinall pointsnear0

    s s (exceptats=s0itself), insomedomainofthe form

    0, 0s s R R .The coefficient 1b ofthe firstnegativepowerofthisseriesisobtainedby

    theformula

    11

    2 Cb f s ds

    i

    (4.2)

    Wecanuse the formula(4.2)toevaluatethe integral:

    12C

    f s ds ib Herewe integratecounterclockwisearound the simple closedpath containing

    0s s in

    its interior, but noothersingularpointsoff(s)onorinsideC.

    The coefficientb1iscalledthe residueoff(s)at 0s s andisdenotedby

    0

    1Re

    2s s

    C

    s f s f s ds

    i

    (4.3)

    Residue integrationcanbeextended from thecaseofasinglesingularity to the caseof

    severalsingularitieswithinthe contourC.Thisisthepurposeofthe residuetheorem:Let

    f(s)beanalytic insideasimpleclosedpathCand onC,except for finitelymanysingular

    points s1, s2,, sn insideC (Figure4). Then the integralof f(s) taken counterclockwise

    aroundCequals2itimesthe sum ofthe residuesoff(s)ats1,s2,,sn.

    1

    2 Rej

    n

    s sjC

    f s ds i s f s

    (4.4)

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    Figure4:The residuetheorem

    The formulafor theresidueatapoleofany orderisgivenby(Kreyszig,1999):

    1

    11Re lim 1,2,3,1 ! kk

    N

    NkNs ss s

    ds f s s s f s k N ds

    (4.5)

    Inthisformula,f(s)has apoleofNthorderat ks s ,and nisthenumberofall poles.Inparticular,for asimplepoleat 0s s theformulais:

    00

    0Re lim

    s ss ss f s s s f s

    (4.6)

    The residueswillbeusedtocomputethe inverseLaplacetransform:

    1 lim2

    c i st

    c i

    f t F s F s e dsi

    L-1

    (4.7)

    In(4.7),wehaveto integrateoverthe lineRe(s)=c.Thislineisbasedonthe assumption

    thatall the singularities(poles)ofthe functionF(s)are onthe leftsideofthe line(Fig.5).

    Figure5:Integrationoverthe lineRe(s)=c

    Ifwe

    are

    to

    apply

    the

    residue

    theorem,

    we

    have

    to

    integrate

    over

    the

    counter

    clockwise

    closed path d . An integral taken over the line Re s c is given as follows. We can

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    describeacirclewiththecentreinthe point0and withsucha largeradiusdthatallthe

    singularitiesofthe functionf(s)are insidethiscircle(Figure6)

    Figure6:Path d andthe insidesingularitiesofthe function f s

    Following the residuetheorem, weshallnow write

    1 Re2 k

    st st

    s skd

    F s e ds s F s ei

    (4.8)

    The integraloverthepath d ispossiblydividedintwoparts:the integraloverthe line

    AB andthe integral overthe restofthe circle BCDEA .

    st st st d AB BCDEA

    F s e ds F s e ds F s e ds

    (4.9)

    Becausethe secondintegral in(4.9)equalszero,weget the followingequationfrom(4.8)

    and(4.9):

    Rek

    st st

    s skd

    F s e ds s F s e

    (4.10)

    andthe integral(28)equalsthe sum ofthe residuesof stF s e at 1 2 3, , , , ks s s s toleftofthelineRe(s)=c:

    1

    lim Re2 k

    c ist st

    s skc i

    f t F s F s e ds s F s ei

    L

    -1

    (4.11)

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    5 AN EXAMPLE

    For the problem (2.1)(2.4), let the autocorrelation function of demand be known, for

    example:

    ddR e

    (5.1)

    Comparing(2.5)(2.7)with(2.8)(2.10)wecanwrite:

    1

    p

    s

    f

    f f

    s

    p

    G ss

    G s e

    G s G s

    eG s

    s

    (5.2)

    The spectraldensityofthegivenautocorrelationfunctionis,asfollows:

    2

    2

    1dd dd s R t

    s

    L (5.3)

    From

    p

    d sD s G s d s

    s weget

    2 2

    2

    1DD

    ss s

    andinthe righthalfplane

    1

    1DD s

    s s

    Due to

    2 1f fG s G s A As

    and 2 1

    f fG s G s A A

    s

    wecanobtaintheoptimalcascadeoperator

    1

    1opt

    s CsW s

    As

    (5.4)

    where

    1

    1

    A eC

    A

    Nowwecanobtainthe operatorofthe optimumregulation

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    1

    1 1 1

    opt

    s

    opt f

    W s s CsG s

    W s G s As e Cs

    inorder

    to

    get:

    a) theoptimalproduction:

    1

    1 1opt opt p

    Csu s W s G s d s

    As s

    (5.5)

    b) theoptimalstock/additionalcapacities:

    1

    11

    s

    opt f opt

    CsZ s G s u s D s e D s

    As

    (5.6)

    Withthe inverseLaplacetransformweobtainthesefunctionsinthe timearea.

    a)the optimalproduction:Informula (5.5),thereare two singlepoles

    1

    1s A

    and2

    1s and consequentlytwo

    residues:

    1

    11 1Re lim

    1 11

    t

    st A

    sA

    Cs e A C es s s

    A A A A A s sA

    1

    1 1Re 1 lim 1

    1 11

    st t

    s

    Cs e C es s s

    A A s s

    A

    Consequently,the functioninthe realtimespaceis, asfollows:

    2

    1

    1Re

    1 1k

    t tAst

    opts s

    k

    A C e C eu t s F s e

    A A A

    and finally

    1

    11

    t

    tAopt

    C Au t e C e

    A A

    (5.7)

    Similarlyit

    is

    possible

    to

    obtain:

    b)the productionwhichreachesthe storehousewiththe delayoftimeunits:

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    1

    1 1

    t

    tAA C C

    v t u t e eA A

    (5.8)

    c)the

    total

    demand

    in

    agiven

    time

    interval

    with

    avariable

    upper

    limit:

    1 t D t D s e L-1 (5.9)

    d)the totaloptimalstock/additionalcapacities:

    t

    tAopt

    Z t M e Ke

    (5.10)

    whereKand Mare constants:

    1

    1

    CK e

    A

    and 1

    C AM

    A

    6 FUZZY CONDITIONS

    6.1 Fuzzy logic

    Fuzzy logic isan innovative formof logicthatallowsadescriptionofthe desiredsystem

    behaviourusing spoken language.Many successfulapplicationshavebeenachievednot

    with conventional mathematical modelling but with fuzzy logic. As a theoreticalmathematical discipline, fuzzy logic is designed to react to continuously changing

    variables and to challenge traditional logic by not being restricted to the conventional

    binaryvaluesof0and 1.Fuzzy logicallowsthe interpretationthatsomething isnot only

    trueorfalse,but isalsoapplicabletopartialormultivaluedtruths.Thisdiscipline is

    especially useful with problems that cannot be simply represented by classical

    mathematicalmodelling for reasons of incomplete data or an overly complex process.

    Statements using subjective categories have a major role in the decision making

    processes of the humans. The contents of these statements may be quantitative,

    uncertain, imprecise or ambiguous, but people can use them successfully for complex

    evaluations.

    A mathematical model is required to implement the human logic into engineering

    solutions. Fuzzy logic makes the representation of the human decision and evaluation

    processespossibleinalgorithmicform.Fuzzylogicoperateswithtermssuchasfuzzyset,

    fuzzy variable, fuzzynumber, fuzzy relation, fuzzy reasoning etc.A classicalBooleanor

    binary logic isbasedon two crisp extremes: yesnow. Yesornow is an answerbeyond

    doubt.The set in thiscase isdefinedbycrispboundaries,whereanelement iseithera

    memberof some crisp setor it isnot,or its membership can be representedwith the

    special functionwhose values are 0 or 1. Fuzzy logic, however, has unclear threshold.

    Fuzzy set is not defined by crisp boundaries, some elements are members with

    membership1,

    some

    elements

    are

    members

    with

    membership

    0,

    but

    certain

    elements

    canalsobemoreor lessmembersof this set an theirmembershipcanbebetween0

    and 1. Membership mapping the objects onto the unit interval [0, 1]. The degree of

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    membership inafuzzyset,for examplenamedA, isexpressedbyacontinuousfunction,

    calledthemembershipfunction A x .The combinationofimpreciselogicrulesinasinglecontrolstrategyiscalledapproximate

    orfuzzy

    reasoning.

    Thus,

    the

    fuzzy

    inference

    is

    the

    process

    of

    mapping

    from

    agiven

    input

    to an output, using fuzzy logic. Generally, there are five parts of the fuzzy inference

    process: fuzzificationof the inputvariable,applicationof the fuzzyoperator (and/or) in

    the antecedent, implication from the antecedent to the consequent,aggregationof the

    consequentsacrossthe rules,andfinally,defuzzification(Ross,2007).

    In fuzzy logic, different values of a given linguistic variable represent concepts, not

    numbers.LinguisticvaluesortermsassociatedwiththelinguisticvariablePRICEcanbe

    obtainedby specific fuzzy sets like LOW, MEDIUM, HIGH etc.A technicalquantity

    PRICE ismeasuredwithnumbers(crispvalue),for example1,000EUR. Incontrast,the

    fuzzy approach uses terms, not numbers. Each fuzzy set like LOW or MEDIUM or

    HIGHis

    formed

    by

    its

    membership

    function.

    This

    function

    represents

    acertain

    degree

    to

    whichacrispvaluebelongstoagivenfuzzyset.Fromexperience,weknowthatapriceof

    10EURor20EUR isLOW,apriceof1,000EURor5,000EUR isHIGH,but 10EUR is

    less than 20 EUR, so the degree of membership of the fuzzy set LOW for the crisp

    number10isgreaterthanfor the crispnumber20. Theprocedureoftransformationcrisp

    numbersintofuzzytermsiscalledfuzzification.Asinglefuzzyruleassumesthe form:

    if x isSET_A,thenyisSET_B,where SET_A and SET_B are linguistic values defined by fuzzy sets in the universes of

    discourseXandY,respectively.The ifpartofthe ruleiscalledthe antecedentorpremise,while

    the

    then

    part

    is

    called

    the

    consequent

    or

    conclusion.

    The

    variables x

    and

    y

    are

    definedonthe setsXandY.The output of the fuzzy process can be the logical union of two or more fuzzy

    membership functions defined in the universe of discourse of the output variable.

    Defuzzification is the conversionofagiven fuzzyquantity toaprecisecrispquantity. In

    literature, at least seven methods (Ross, 2007) are common for defuzzifying: max

    membership principle, centroid method, weighted average method, meanmax

    membership,centreofsums,centreofthe largestarea,first(last)ofmaxima.6.2 Fuzzy reasoning

    Inprincipleeverysystemcanbemodeled,analyzedandsolvedbymeansof fuzzy logic.

    Due to the complexityof the givenproblemand the subjectivedecisionsof customers,

    which are better described with fuzzy reasoning, it is advisable to introduce a fuzzy

    approach. Some basic solutions of the control problems using fuzzy reasoning were

    presented inthe paper (Usenik,Bogataj,2005).For someproblemsaboutthe controlof

    the powersupplysystem,weproposefuzzyreasoning.Itisobviousthatdecisionmakers,

    whensolvingeverydayproblems incontrolofsystems,operatewithfuzzy logic(Terano,

    1992).

    Our proposed fuzzymodelwillbebasedon these assumptions,whereby the usual five

    stepshave

    to

    be

    taken:

    fuzzification

    of

    the

    input

    and

    output

    variables,

    application

    of

    the

    fuzzy operator in the antecedent, implication from the antecedent to the consequent,

    aggregationofthe consequentsacrossthe rules,and defuzzification.

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    6.3 Fuzzification

    In the fuzzification phase we have to define fuzzy sets for all fuzzy variables (input and

    output)and definetheirmembershipfunctions.

    Let us assume for example that the demand id at the location jz depends on a) the

    market area, b) the density of the area, c) price, d) season and d) uncertainty. The

    demand is in fact the basic variable, on which the behaviour of all retailers depends

    (Figure7).

    Figure7:Outputfuzzyvariabledemanddependson5inputfuzzyvariables

    We assume that all expressions are fuzzy variables, market area, density of the area,

    price, season and uncertainty are input fuzzy variable, and demand is an output fuzzy

    variable.Everyfuzzyvariableispresentedbymoreterms,for example:

    a) inp utfuzzyvariableMARKETAREAisrepresentedby: SMALL,BIG,

    b) inp ut fuzzy variable DENSITY OF THE AREA is represented by: WEAK, MEDIUM,

    STRONG,

    c) inputfuzzyvariablePRICEisrepresentedby: LOW,MEDIUM,HIGH,

    d) inp utfuzzyvariableSEASONisrepresentedby: LOW,HIGH,

    e) inp ut

    fuzzy

    variable

    UNCERTAINTY

    is

    represented

    by:

    SMALL,

    MEDIUM,

    BIG,

    VERY_BIG,

    f) output fuzzy variable DEMAND is represented by: VERY_LOW, LOW, MEDIUM,

    HIGH,EXTREMELY_HIGH.

    For everyfuzzysetand for everyfuzzyvariable, wehavetocreatemembership functions.

    For the fuzzy variable DEMAND they could be as shown in Figure 8. On the xaxis, we

    measurethevariableDEMANDgiveninunitslikekWh,MWh and soon, dependingonour

    data. On the yaxis, we measure membership for every possible demand and for every

    fuzzyset VERY_LOW,LOW,MEDIUM,HIGH,EXTREMELY_HIGH.

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    Figure8:MembershipsfunctionsoffuzzysetsforfuzzyvariablePRICE

    6.4 Fuzzy model

    Inourcasewecandefinenphasemodelwithatleastnruleblocksandnsetsofinput/output

    fuzzyvariables(Fig.9),(Usenik,2009).

    Figure9:Thestructureofthefuzzysystem

    These fuzzy variables can solve the problem in general and can introduce quite a good

    startingpointfor furtheractionsand stepstobetakeninthe processofdecisionmaking.

    Due to the simplicity of this process, all membership functions will be of a simple

    triangular and trapezoidal shape. Of course, in further iterations and studies of market

    behaviour relevant for the customers demands and requests, we shall state more

    sophisticatedconditionstofindanswerstoquestionsinrealworldsituations.6.5 Fuzzy rules inference

    The computationof fuzzy rules iscalled fuzzy inferenceandconsistsof threesteps: the

    application of the fuzzy operator (and/or) in the antecedent, the implication from the

    antecedent to the consequentand the aggregationof the consequentsacross the rules.

    The firststepdeterminesthe degreetowhichthe completeIFpartofthe ruleissatisfied.

    In thisstep,weusuallyuse theoperatorOR for the minimumand the operatorAND for

    the maximum.The secondstepmakesuse ofthe supportofthepreconditiontocalculate

    thesupport

    of

    the

    consequence.

    Finally,

    the

    aggregation

    step

    determines

    the

    maximum

    degreeofsupportfor eachconsequence.

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    In our work, we applied FuzzyTech software (FuzzyTech, 2000). In accordance of this

    softwaretool,the ruleswereautomaticallycreated.

    6.6 Defuzzification

    The resultfromthe evaluationoffuzzyrules isfuzzy.Defuzzification isthe conversionof

    a given fuzzyquantity to aprecise crispquantity. The most frequentlymethodused in

    praxis isCoMdefuzzification (theCenterofMaximum).Asmore than one output term

    can beacceptedasvalid, the defuzzificationmethod shouldbea compromisebetween

    differentresults.The CoM methoddoesthisbycomputingthe crispoutputasaweighted

    averageofthe termmembershipmaxima,weightedbythe inferenceresults(Ross,2007).

    CoM is a kindof compromise between the aggregated resultsofdifferent termsjof a

    linguisticoutputvariableandisbasedonthemaximumYjofeachtermj.

    7 CONCLUSION

    Inthisarticle,the modelofthe controlofthe powersupplysystemhas beenpresented,

    provided that the input functions (and for reason of linearity and stationarity, also an

    outputfunction)weregivenasstochasticorfuzzyprocesses.Onthe basisofthe specific

    items of the systems, the mathematical model of a system for the possibility of

    input/outputfunctionsbeingrandomprocesseswas createdandsolved. Incaseoffuzzy

    conditions, demand and other functionswere represented as fuzzy sets. In the future,

    researchwill

    have

    to

    be

    done

    in

    order

    to

    create

    amathematical

    model

    of

    the

    power

    supplysystemfor fuzzyconditionsingeneral,showninFig.8.Oneofthe veryinteresting

    and highly realisticpossibilities is the creationof the fuzzymodel forsolvingor,better,

    predicting optimal energy capacities and technologies for permanent and reliable

    electricitysupply,consideringriskcontrol(Fabijan,Predin,2009).Thisresearchispartof

    the realizationofthat.

    References

    [1]

    DiStefano,

    J.J.,

    Stubberud,

    A.R.,

    Williams,

    I.,J.:

    Theoryand

    Problems

    of

    Feedback

    and

    ControlSystems,McgrawHillBookCompany,1987.

    [2] Usenik, J., Vidiek, M., Vidiek M., Usenik, J.: Control of the logistics system using

    Laplacetransformsandfuzzylogic.Logisticsandsustainabletransport,2008,vol.1,issue1,pp.119.

    [3] Usenik,J.:ControlofTrafficSystem inConditionsofRandomorFuzzy InputProcesses,

    PrometTrafficTraffico,2001,Vol.13No.1,p.18.

    [4] Bogataj,M.,Usenik,J.:Fuzzyapproachtothespatialgamesinthetotalmarketarea.Int.j.prod.econ.[Printed.],2005,vol.9394,pp.493503.

    [5] Usenik, J., Bogataj, M.:A fuzzy set approach for a locationinventorymodel. Transp.plann.technol.,2005,vol.28,no.6,pp.447464.

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    JanezUsenik JETVol.2(2009) Issue3

    [6] Schneeweiss, C.: Regelungstechnische stochastische Optimierung Verfahren inUnternehmensforschungundWirtschsaftstheorie,SpringerVerlag,Berlin,1971.

    [7] Kreyszig, E.:Advanced Engineering Mathematics, JohnWiley& Sons, Inc.,New York,1999.

    [8] Ross,J.,T.:FuzzyLogicwithEngineeringApplications,2nded.,JohnWileySonsLtd,TheAtrium,SouthernGate,Chichester,England,2004,reprinted2005,2007.

    [9] Terano, T., Asai, K., Sugeno, M.:FuzzySystemsTheoryand itsAplicactions,AcademicPress,Inc.,SanDiego,London,1992.

    [10] Usenik,J.:Fuzzyapproach inprocessofmultipleattributedecisionmaking,JETJournalofEnergytechnology,Volume1(2009),p.p.4358.

    [11] FuzzyTech,UsersManual,2000,INFORMGmbH,InformSoftwareCorporation.

    [12]

    Fabijan,D.,Predin,A.:Optimalenergycapacitiesand technologies forpermanentandreliable electricity supply, considering risk control, JET Journal of Energy technology,

    Volume2(2009),p.p.6984.

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    JETVolume2(2009),p.p.4764

    Issue3,August2009

    http://www.fe.unimb.si/si/ejet/index.php

    THE CALCULATION OF THERMODYNAMIC

    PROPERTIES FOR HYDROCHLORIC AND

    COPPER COMPOUNDS IN A HYDROGEN

    PRODUCTION PROCESS

    IZRAUN TERMODINAMINIH LASTNOSTIV HIDROKLOROVIH IN BAKER KLOROVIH

    KOMPONENTAH V PROCESU

    PROIZVODNJE VODIKA

    JurijAvsec1,GregF.Naterer2,AndrejPredin11UniversityofMaribor,FacultyofEnergyTechnology,

    Hoevarjevtrg1,8270Krko,SLOVENIA

    2UniversityofOntarioInstituteofTechnology,Oshawa,Ontario,Canada

    Keywords:Hydrogenproduction,CuClcycle,thermophysicalproperties,statistical

    thermodynamics

    Abstract

    Efficientand sustainablemethodsofclean fuelproductionareneeded inallcountriesof the

    world in the faceofdepletingoil reservesand theneed to reducecarbondioxideemissions.

    With commitments for a hydrogen village, a hydrogen airport and a hydrogen corridor, the

    CanadianprovinceofOntariohasalreadybeguntomovetowardahydrogenfueledeconomy.

    However,akeymissingelement isa largescalemethodofhydrogenproduction.Asacarbon

    based technology, the predominant existing process (steammethane reforming (SMR)) is

    unsuitable.

    Correspondingauthor:Assoc.Prof.JurijAvsec,,Tel.:+38676202217,Fax:+38626202222,

    Mailingaddress:Hoevarjevtrg1,8270Krko,SLOVENIA

    Emailaddress:[email protected]

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    J.Avsec,G.F.Naterer,A.Predin JETVol.2(2009) Issue3

    This paper focuses on a copperchlorine (CuCl) cycle, and the models of calculating

    thermodynamic properties. It discusses the mathematical model for computing the

    thermodynamicpropertiesforpuresubstancessuchasH2,CuClandHCl,whichareimportantin

    hydrogenproduction

    in

    their

    fluid

    phase,

    with

    the

    aid

    of

    statistical

    chain

    theory.

    The

    constants

    requiredmakethiscomputation,suchasthecharacteristictemperaturesofrotation,electronic

    stateetc.,andthemomentsof inertiaareobtainedanalytically,byapplyingtheknowledgeof

    theatomicstructureofthemolecule.Theproceduresforcalculatingessentialthermodynamic

    propertiessuchaspressure,speedofsound,thespecificheat,volumetricexpansioncoefficient,

    enthalpyandentropyarepresented.Tocalculate the thermodynamicpropertiesofLennard

    Joneschains,wehaveusedtheLiuLiLuandTangLumodels.Thethermodynamicpropertiesof

    theLennardJonesmixturesareobtainedusingtheonefluidtheory.

    Inrecentyears,thermodynamictheoriesbasedonstatisticalthermodynamicshavebeenrapidly

    developed.Fluidswithchainbondingandassociationhavealsoreceivedmuchattention.The

    interestin

    these

    fluids

    isdue

    to

    the

    fact

    that

    they

    cover

    much

    wider

    range

    of

    real

    fluids

    than

    sphericalones.Agood theory for these fluidswillbeverybeneficial forchemicalengineering

    applications, by reducing the number of parameters, and making them more physically

    meaningfulandmorepredictable.

    Intechnicalpractice,energyprocessesareofvitalimportance.Inordertodesigndevicesinthis

    field of activity, it is necessary to be familiar with the equilibrium and nonequilibrium

    thermodynamicpropertiesofstateinaoneandtwophaseenvironmentforpurerefrigerants

    andtheirmixtures.Tocalculatethethermodynamicpropertiesofreal fluid,theLiuLiLu(LLL)

    (revisited Cotterman) equation of state, based on simple perturbation theory and SAFTVR

    equationofstateforLJchainfluidwasapplied.Wedevelopedthemathematicalmodelforthe

    calculationof

    all

    equilibrium

    thermodynamic

    functions

    of

    state

    for

    pure

    hydrocarbons

    and

    their

    mixtures.

    Inthispaper,wehavedevelopedananalyticalmodelbasedonthestatisticalthermodynamics

    andchaintheoryforpurecomponentssuchasH2,CuClandHClinthefluidregion.

    PovzetekToplogredni plini, ki nastajajo pri zgorevanju fosilnih goriv, predstavljajo veliko potencialno

    nevarnost za prihodnost obstoja loveka. Zaradi zmanjevanja emisije ogljikovega dioksida v

    ozraju inzaradizmanjevanjazalog fosilnihgorivv svetujepotrebnopreitivprihodnostina

    novetehnologijepridobivanjagoriv.Kanadajezrazvojemvodikovihvasi,vodikovihletalie

    priela z aplikacijo vodikovih tehnologij. V principu manjka za primer irokomasovneproizvodnjelemetodazapridobivanjevodikavvelikihkoliinah.

    lanekopisujebakerklorovprocesintermodinaminelastnostivomenjenemprocesu.Vlanku

    jeprikazanmodel,kako izraunati termodinamine lastnostikomponentkotsovodik,CuCl in

    HCl.Omenjene komponente so zelopomembne vproizvodnemprocesupridobivanja vodika.

    Omenjenametodajepovsemanalitina inzadoloevanjetermodinaminih lastnostiuporablja

    statistinomehanikoinmolekularnostrukturomaterialov.

    Talanekopisujemodelizraunatermodinaminihlastnosti,kotsonaprimertlak,hitrostzvoka,

    specifinetoplote,volumetriniekspanzijskikoeficientinentropija.Vtanamensmozaizraun

    LennardJonesovih

    verig

    uporabili

    Liu

    LiLu

    jev

    model.

    Termodinami

    ne

    lastnosti

    zmesi

    so

    izraunanenaosnovienofluidneteorije.Predstavljenmodelpredstavljaprvitovrstenposkusv

    svetovni literaturi za izraun termodinaminih veliin, ki se uporabljajo v bakerklorovem

    procesu.

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    Thecalculationofthermodynamicpropertiesforhydrochloricandcoppercompoundsinahydrogenproductionprocess

    1 INTRODUCTION

    Currently, the world consumes about 85 million barrels of oil and 104 trillion cubic feet of

    natural

    gas

    per

    day,

    releasing

    greenhouse

    gases

    that

    lead

    to

    global

    warming.

    In

    contrast,

    hydrogenisacleanenergycarrier.Somehavequestionedwhetherthehydrogeneconomyis

    feasible inthenearfutureorremainsadistant ideal.However,theglobalhydrogenmarket is

    alreadyvaluedatover$282billion/year,growingat10%/year,risingto40%/yearby2020,and

    reaching several trillions of dollars by 2020. In Alberta, Canada, the oil sands need large

    amounts of hydrogen to convert bitumen to synthetic crude and remove impurities. A key

    challengefacingthehydrogeneconomyisamoreefficient,sustainableandlowercostmethod

    of hydrogen production. As a carbonbased technology, the predominant existing process

    (steammethanereforming(SMR)isunsustainable.

    Ratherthanderivinghydrogenfromfossilfuels,apromisingalternative isthethermochemical

    decompositionofwater.Electrolysis isaproven,commercial technologythatseparateswaterinto hydrogen and oxygen using electricity. Net electrolysis efficiencies (including both

    electricity and hydrogen generation) are typically about 24%. In contrast, thermochemical

    cycles to produce hydrogen promise heattohydrogen efficiencies up to approximately 50%.

    This article examines the thermophysical properties of a specific cycle called the copper

    chlorine (CuCl) cycle, with particular relevance to nuclearproduced hydrogen. A conceptual

    schematicoftheCuClcycleisshowninFig.1.

    IntheCuClcycle,waterisdecomposedintohydrogenandoxygenthroughintermediateCuCl

    compounds [4,5]. Nuclearbased water splitting requires an intermediate heat exchanger

    betweenthe

    nuclear

    reactor

    and

    hydrogen

    plant,

    which

    transfers

    heat

    from

    the

    reactor

    coolant

    to the thermochemical cycle. An intermediate loop prevents exposure to radiation from the

    reactorcoolant in thehydrogenplant,aswellascorrosive fluids inthethermochemicalcycle

    enteringthenuclearplant.

    This paper develops new models for calculating the thermodynamic properties of copper

    chlorinecompoundsintheCuClcycle.Statisticalassociatingfluidtheoryisusedtocalculatethe

    thermodynamicproperties,basedontheCottermanequationofstate[13],aswellastheTang

    Lu model [3] from the OrnsteinZernike equation of state and perturbation chain theory.

    Predictive mod