翻译Word文档下载推荐.docx
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翻译Word文档下载推荐.docx
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系别:
能源与环境工程学院
专业:
建筑环境与设备工程
班级:
建环101
姓名:
毕佳建
学号:
2010305131
外文出处:
BULIDINGSIMULATION2005
指导教师评语:
签字:
2014年4月25日
BUILDINGINTEGRATEDHEATINGSYSTEMS
KlausKaaeAndersena&
HenrikPoulsenb
bDTI-Energy,TheDanishInstituteofTechnology,2630Taastrup,Denmark
aDepartmentofMathematicalModelling,TheTechnicalUniversityofDenmark,
2800Lyngby,Denmark
ABSTRACT
Thispaperpresentsthepreliminarymodellingper-spectivesofanongoingprojectwhereaflexiblesimulationtoolforcomponentandsystemanalysisofdistrictheatingconsumerinstallationsisdeveloped.Thesimulationtoolmakesitpossibletosimulatedistrictheatingconsumerinstallationscontainingwaterbasedcentralheatingsystems,domestichottapwatersystems,buildingsaswellasloadpredictionsofthesystems.Themainpurposeoftheprojectistoimprovetheinteractionofthesystemcomponents,decreasetheenergyconsumptionandanalyzetheperformanceoftheheatingsystemandtherelationbetweenthebuildingandtheheatingsystem,BuildingIntegratedHeatingSystem.Thisisdonewithemphasisonincreasingthesystemperformanceofthedistrictheatingsystem.Thepaperpresentsthemodellingapproachwithmainemphasisonlumpedparametermodellingusingstatisticalmethods.Somepriorresultsarediscussedandillustratedthroughexamples,includinganalysisoftheheatdynamicsofabuildingandanewapproachonhandlingdiscontinuitiesexemplifiedinthemodellingofthe
transientflowspipes.
Keywords:
BuildingIntegratedHeatingSystems,DistrictHeatingSystems,LumpedParameterModelling,Simulationstudies.
INTRODUCTION
SincethefirstenergypricecrisisintheearlyseventiestheenergypolicyinDenmarkhasbeenfocusedonhowtoreducetheconsumptionandthedependencyofasinglefuel.InrecentyearstheenergydemandinnewbuildingsinDenmarkhasbeenreducedconsiderablyduetonewbuildingregulations.Thereducedheatdemandandthegrowingfocusontheindoorclimateincreasestherequirementsoftheperformanceoftheheatingsystemandtheinteractionbetweenbuildingandtheheatingsystem,BuildingIntegratedHeatingSystem.Morethan60%oftheheatconsumptionisbasedondistrictheating,DH,duetothenationalenergyplanssincethesecondenergycrisis
inthelateseventies.Todaythesystemsarechar-
acterizedbypooledoperationwithcombinedheatandpowerplantsmainlybasedonincineration,coalandnaturalgas.Thesuppliershavemadeagreateffortonoptimizingthesystemperformanceinordertominimizethecosts;
duringthelastfifteenyearstheoptimizationprocesshasfocusedontheproductionplantsandthedistributionsystems.Integrationoftheconsumerinstallationsintheprocessstartedaroundfiveyearsago,asthenaturallaststepinoptimizingtheoverallefficiency.Thedesignandoperationoftheconsumerinstallationsareimprovedwithrespecttothesystemperformance,i.e.theinstallationsmustoperateatalowtemperaturelevelwithahighcoolingandfewpeaks.Themanufacturersofthecomponentsareveryimportantinthisprocessandtheproductdevelopmenthaschangedfromfocusingonthecomponent(suboptimization)tofocusingontheinteractionofthecomponents(systemoptimization).Developingnewproductsorimprovingexistingistraditionallyacomplexandexpensivetaskincludingnumeroustestsinthelabfollowedbyfinaltestsofaprototypeinsiu.Todayalargepartofthesetestscanbereplacedbycomputersimulationstudies.Theuseofdynamicmodelsincomputersimulationstudieshasproventobeaperceptiveandpracticalmethodtoanalyzetheperformanceandthecontrolstrategiesinheatingsystems.Thence,thedynamicsoftheheatingsystemcanbeanalyzedsecondbysecondwithvaryingheatsupplyfrompersons,machinesandthesuninordertominimizetheheatdemandinthebuildingsandoptimizethethermalcomfort.However,theprospectsfromapplyingsimulationstudiesindevelopmentofsystemcomponentsdependsstronglyontheaccuracyandflexibilityofthemodelsusedforthesimulation.Thepaperpresentsthemodellingapproachandtheideabehindaprojectconcerningthedevelopmentofamodellibraryforsimulationpurposes.
THEMODELLINGOBJECTIVE
TheprojectisajointprojectwithcollaboratorsfromsomeofthelargestmanufacturersofDH
CompoentsinDenmarkandpublicresearchinstitutes.ThemodellingobjectiveoftheprojectistoestablishamodellibraryofthecomponentsintypicalDHsystems,sketchedinFig.1,asafoundationforsystemanalysis,simulationstudiesandproductdevelopment.Anessentialaspectoftheproject,is,thatthemodellingofsystemcomponentsiscontinuouslyvalidatedonexperimentaldatatoensureaccuracyandreliabilityinanalysis
Fig.1:
SketchofatypicalDHsystem.Thecombinedheatandpowerplantsuppliestheconsumerviaheatexchangerswithhotwater(solidline)forheatinganddomesticwater.Afterconsumption,thecooledwater(dottedline)returnstothepowerplant.
andsimulationstudies.Forthisreasonsanexperimentalsetupareusedasanempiricalbaseformodelvalidation.
Inordertoanalyzetheinfluencefromtheheatingsystemontheindoorclimatethemodelsaredividedintotwocategories,namely:
(i)Modelsofsystemcomponents.
(ii)Modelsofthetotalsystem.
Themodelsofsystemcomponentsaregatheredinthemodellibraryandmaybeusedforanalyzingpurposesandsimulationstudies.Theuserofthemodellibrarycanselectcomponentsfromagraphicaluserinterface(GUI)environment.Specificarrangementsorsetupsarecreatedusingadrag-and-droptechniqueofthecomponentsintoaworksheet,wherethecomponentsareconnectedintoadesiredsetup.Themodellibraryincludesmodelsof:
•Plateheatexchangers.
•Radiators.
•Thermostaticandpressurereliefvalves.
•Pipesandfittings.
•Pumps.
•Thermalzonesandbuildings.
Bydescendingorder,eachclassofthecomponentscf.above,containdifferentmodelsofeachcomponent.Themodelsmayvaryincomplexity,controlstrategiesanduserinterface.Furthermore,eachcomponentmaybeadjustedtoaspecificproduct,i.e.physicalpropertiessuchasheatcapacities,resistances,sizesetc.maybecontrolledbytheuser.
Themodelinterface
AssketchedinFig.1thetotalDHsystembesidesthedynamicsofthepowerplantisconsidered.Thesystemisaffectedbyclimatevariablesaswellastheloadfromthepowerplant,interactionbetweencomponents,humanactivityetc.Inordertoachieveawell-defineduserinterface,onlythemodelsofthetotalsystemandentireroomsandbuildingsmaybeaffecteddirectlybytheclimatevariables,suchastheoutdoortemperature,solarradiationetc.Systemcomponents,suchasradiatorsandvalves,areonlyindirectlyaffectedbytheclimatevariables,i.e.viathebuildinginwhichtheyareplaced.Theinterfaceofthesystemcomponentsareindoortemperatures,supplyandreturnwatertemperaturesaswellasflowandpressuredropinpipes.Themodelsofsystemcomponentsusedinthesimulationtoolaremainlylumpedparametermodels.
Thereareseveralargumentsforpreferringandusinglumpedparametermodelsforsystemcomponentscomparedtoblackboxmodelsandmodelsintermsofpartialdifferentialequations.Firstly,lumpedparametermodelsbasedonthelawsofnaturearedirectlyphysicallyinterpretable,akeyissuewheretheblackboxmodelsfail.Secondly,lumpedparametermodelsintermsofordinarydifferentialequationsarefarsimplertoestablishandforsimulationpurposescomparedtodistributedparametermodels,i.e.modelsintermsofpartialdifferentialequations.Thelumpedparametermodelsmaybeusedfor’standalone’simulationstudiesortogetherwithothermodelsofcomponentsinsimulationstudiesofcomponentinteractions.Themodelsofatotalsystemmayinprinciplebeasystemoflumpedparametermodels,correspondingtoasetupoflumpedparametersmodelsofthecomponentsinthesystem.However,forlargescalesimulations,thismaynotbenecessaryoreventocomplexatask.Whenonlytherelationbetweentheinputandtheoutputsignalsofthesystemisofinterest,thetransferfunctionrepresentationisregardedasasufficientdescriptionofthesystem.Theuserinterfaceisstillphysicallyinterpretable,e.g.flowrates,supplytemperaturesandpressuredrops,whereasthetransferfunctionfrominputtooutputisnotphysicallyinterpretable.
THEEXPERIMENTALSETUP
Inordertogetanempiricalbaseforthedynamicalmodelsofthecomponentsintheconsumerinstallationtheinput-outputrelationshipanddynamicalcharacteristicsofeachcomponentaswellastheinteractionbetweenthesystemcomponentsareinvestigatedinanexperimentalsetup.ThissectionpresentsadesignedtestrigfordetailedtestingofDHsystemcomponents.Theexperimentalsetup,a100kWtestrig,correspondingto20-30apartments,representsatypicallyconsumerinstallationinWesternEuropeancountries.Theheatingsystemisseparatedfrom2theDHsystembyaheatexchanger.Theradiatorsystemisdividedintothree,wherehotwatertanksemulatethedynamicsofeachzone.Theloadinthedomestichotwatersystemisemulatedbypredictions,i.e.tapprogramsfromacomputer.Thedomestichotwaterisproducedinstantaneousinaheatexchanger.Inthemainsetupoftheheatingsystemonlytheloadfromtheradiatorsystemisofimportance,nottheperformanceoftheindividualradiator.Therefor,theempiricaldataoftheradiatorisassembledinaseparatesetup,wheretherm-visionisusedtoverifytheheattransferfromtheradiator.Theheatexchangers,radiatorsandhotwatertanksareconnectedthroughpipesandfittingswherepumpsandvalvescontroll
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