高校楼宇电气节能

HigherEducationBuildingEfficientElectricalDesignMatthewCobb,NathanJustin,AdelEl-Shahat,RamiJ.HaddadDepartmentofElectricalEngineeringGeorgiaSouthernUniversityStatesboro,Georgia30458Email:{aahmed,rhaddad}@georgiasouthern.eduAbstract—Thispaperencompassesdesignanddevelopmentforanenergyefficientelectricaldesignofacommercialstructureforapost-secondaryacademicinstitution.Thegoalofthisworkistodesignacompleteandsafeelectricalsystemthatreducespowerconsumptionandincreasesuserfriendlyoperationofallhighandlowvoltageequipmentfortheendusersofthebuilding.ComputerAidedDesign(CAD)andBuildingInfor-mationModeling(BIM)toolsareusedtodesignandmodeltheelectricalsystems.Inthispaper,astepbystepprocesshasbeenpresentedtoaccomplisheachtasktosuccessfullycompletedesigns.Backgroundinformation,goals,andmethodologiesareincludedwithsupportingmaterialtoshowcasethatthisdesignhasahighprobabilityofachievingallexpectations.Thedeviceandequipmentlayoutofthefloorplansforeachtypeofelectricalsystemweredesigned.Inaddition,allelectricalloadandlightingcalculationswereperformedusingMicrosoftExcelandAcuityBrandsVisual2012.Furthermore,threedimensionalmodelingofcomponentswithinthebuildingenvironmentwaspresented.Schematicfloorplanlayoutson30”x42”architec-turalsheetsalongwithhighlightingimportantpointsfromourtechnicalspecificationswerealsointroducedandpresented.Alsosimulationresultsobtainedfromthelightinganalysissoftwarewerepresentedtodemonstratethecompletionofthepowerdistributiondiagram,thelightningprotectiondesign,andalltechnicaldetailedinstallationdrawingsinAutoCADMEPandAutodeskRevit.Keywords—Energy,Design,Efficient,Building,Education,Electrical.I.INTRODUCTIONIntoday’ssociety,buildingsareverycomplexandhavemanydifferentsystemsimplementedwithinthem.Someofthesesystemsincludeheatingandairconditioning,firealarmsystems,elevators,anddatasystems.Eachofthesesystemshasnumerousstandardsthatmustcomplywith[1–5].TheNationalElectricCode(NEC)hasthousandsofpagesofreg-ulationsthatincludeveryspecificdetails.Themostimportantprioritythatmustbeconsideredwhendesigningabuildingissafety[1],[6].Allcalculationsmustbeaccuratebecausethegeneralpublicwillbeatriskincaseofanymalfunction.Therefore,safetyisoneofthemainobjectivesthatmotivatedthecreationoftheNECinthefirstplace.Allbuildingsmusthaveexitsandalternateroutes.Theymustalsoincludefirealarmsandmaximumoccupancydata.Manyorganizationswhichdealswithdifferentaspectsofbuildingregulationshavedevelopedovertheyears.TheNationalFireProtectionAgencyisoneofthoseagenciesthatishighlyinvolvedwithallbuildingstructures[2],[7].TheAmericanSocietyofHeating,Refrigerating,andAir-ConditioningEngineersisanotherorga-nizationthatgovernstheenergyrequirementsforbuildings[5],[8].TheBuildingIndustryConsultingServiceInternationalisanorganizationthatsetsbestpracticesandstandardsofhowtelecommunicationsinbuildingsaredesignedandinstalled[6].Typicallymostelectricdesignsarecompletedbyconsultingcompanies.Dependingonthebuildingsizeandcomplexity,therecouldbeoneortwoengineersworkingontheprojectuptoanentireteam.Thedurationoftheprojectmayalsovarydependingonthebuildingcomplexityandsize.Thefirststepinthedesignprocessisplacingcomponentsonthefloorplansheets.Thenthecalculationsaremadeinordertosizetheelectricalpanels.Bytheendoftheprocess,everythingfromtransformersizetowiresizeisspecified.Thisinfor-mationisgiventothecontractoralongwithnumerousotherspecifications.Thecontractorthenconstructsthebuildingandreturns”asbuilt”markupsontheplanstothedesigningteam.ThistypeofelectricaldesignistypicallydonebyEngineersinTraining,EngineerswhohavepassedtheFundamentalsofEngineering(FE)exam,orProfessionalEngineers.Big-scaleprojectsrequiremoreworkingforceinvolvement,aswellasmoreprofessionalengineerstomakesureallthecalculationsanddesignsareaccurateandcomplywiththedesigncode.Inthispaper,allelectricalracewaysystemsandsupportingdevices,exceptforconcreteencasedductbanks,areapplied.Electricalracewaysystemincludes,butnotlimitedto,allelectricalraceways,boxes,fittingsandsimilarcomponentsnecessaryforacontinuouspathwayfortheinstallationofcablesorconductors.Supportsareanydevicesorcomponentswhichareusedtosupportracewaysorelectricalequipment.II.SIMULATIONANDIMPLEMENTATIONThesimulationwasusedforthepointbypointlightinganalysis.Inordertofullyunderstandhowthelightinganalysisisperformed,thelightinganalysismethodologymustbeconsideredfirst.ThezonalcavitymethodwasusedinordertogeneratearoughestimatebeforesimulatingeachroomwiththeVisual2012software.Thismethodisusuallyusedtoaccuratelycalculatetheilluminanceofaroom.Therearethreespacestoconsiderinaroom,theceilingcavity,theroomcavity,andthefloorcavity.Eachcavityhasitsowncavityratio.Thisratioisdeterminedbythedimensionsofthearea978-1-5090-2246-5/16/$31.00c©2016IEEEFig.1.Room122Excelbeingcalculated.Abasicformulaforcalculatingagenericcavityratioisasfollows:CavityRatio=2.5×cavityheight×cavityperimetercavitybasearea(1)Oncethecavityratioisdetermined,thecavityreflectancemustbeevaluated.ThesevaluesarethenusedtodeterminetheCoefficientofUtilization(CU).Thiscoefficientisusedtodeterminehowmanylampsareneededinaroomifgivenaspecificfoot-candlevalue.Inthisproject,alevelof50foot-candlesfortheclassroomsaswellas80-50-20reflectancevaluesforceiling,walls,andfloorswereused.Thesearecom-monlyusedvaluesinmostbuildingdesigns.Thereflectancevaluesmustbeconvertedtoeffectivereflectancevalues.Thesevaluesarethenusedinconjunctionwithatabletolookupthecoefficientofutilization(CU).Finally,thefollowingequationisusedinconjunctionwithsomeparameterssuchasthelumensperlamp,numberoffixtures,lampsperfixture,CU,roomarea,andthelightlossfactor(LLF)toevaluatethedesiredfoot-candlelevel.Foot−candles=No.offixtures×lampsperfixture×lumensperlamp×CU×LLFarea(sq−ft)(2)Inordertodothecalculationsforalltheroomsinabuilding,anexcelspreadsheetisused.Thedimensionsofeachroom,theroomcavityratio,andspecificinformationforeachlightfixtureareusedalongwiththefoot-candlevalueforeachroomasatarget.Usingthisdata,thenumberoffixturesthatwouldbeneededineachroomiscalculated.AfterthatlightingfixturesareplacedontotheplansaccordingtoNECregulations.Usingtheexcelspreadsheet,averycloseestimateforthefoot-candlesineachroomisobtained.Figure1illustratestheexcelsheetcalculationsforroom122.AmoredetailedlightinganalysiscanbeobtainedbyusingtheVisual2012software.Whenusingthesimulationsoftware,thereareonlyafewparametersneeded,namely,thenumberoffixturesineachroom,thelightingfixturefile,andthedimensionsofeachroom.Eachroomiscreatedaccordingtoitsdimensions.Thenthelightingfixturefileandthenumberoffixturesareuploaded.Atthispointthefixturesareplacedintheroomanda3Dpictureoftheroomcouldbesimulated.Withthisview,thelightconcentrationcanbedetermined.Themostimportantparameterinthisanalysisistheaveragenumberoffoot-candlesintheroom.ThisapproachwasusedanditsresultswerecomparedwiththeresultsgeneratedbytheFig.2.Room122Simulationexcelspreadsheet.Figure2illustratesthelightconcentrationinfoot-candlevalueforroom122basedonthesimulation.Usingbothapproaches,aslightdifferencebetweentheExcelspreadsheetandthesimulationresultswasobserved.Forroom122,theExcelaverageresultwascalculatedtobe48.3foot-candleswhilethesimulationgaveanaverageresultof52foot-candles.Thesimulationgivesamoreaccuratevalueandalsoshowstheconcentrationoflightineachareaoftheroom.Theexcelformulaisonlyusedtogiveanestimatesothereisareferenceastowhatthesimulationshouldgiveasaresult.Thecollegebuildingstructureselectedwasatypicalcollegebuildingthatcanbefoundonmostsmallcollegecampuses.Itconsistedmainlyofatwostorieswithmanyclassroomsandoffices.Figure3illustratestheeducationalbuildingstructureusedinthisproject.Fig.3.EducationalBuildingStructureOncethebuildingwaschosenthenextstepinrealap-plicationwouldbetodiscusswiththecustomerthekindofcomponentstobeusedinthebuilding.Thisincludesanythingthatuseselectricity.Identifyingthelocationstoplacethesecomponentsandtheelectricalrequirementsareimportanttooptimallycircuitandaccuratelysizeallofthepanelsinthebuilding.Onceallofthecomponentsareknown,theyareplacedonthelayoutinRevit.Allofthelights,smokedetectors,firepullstations,poweranddatareceptacles,floorboxes,audibleandvisualalarms,andwirelessaccesspointsmustbeplacedaccordingtoregulation.AnythingthatconsumeselectricitymustbeplacedinaccordancetoacodethatissetbytheNECorbestpracticesstandardbyBICSI.Figure4isanexampleofthecomponentsinatypicalroom.Thelightsarenotdisplayedinthisviewbecausethereisaseparatelightingsheet.Thisfigureshowsfloorboxeswithduplexreceptaclesandtelecommunicationsoutlets,wallduplexreceptacles,walltelecommunicationboxes,aceilingmountedtelecommunicationsjunctionboxaswellasceilingmountedduplexreceptacle,andamotorloadfortheprojectorscreen.Fig.4.ComponentsPlacementExampleFigures5and6illustratethepowerplandesignsforthefirstandthesecondfloor.Fig.5.FirstFloorPowerPlanThefollowingistheappropriatecircuitinginformationthatwascoordinatedbetweenthepowerplansandeachrespectiveFig.6.SecondFloorPowerPlanpanelschedule.Branchcircuitson208/120Vthatare20ampsinglepoletripcanhandle20Ax120V=2400VA.Becauseofthevariationsofthetime-currenttripcurvesofmoldedcasethermalmagneticcircuitbreakers,80%ofthisloadresultingin1920VAwasused.Becauseofthedistinctpossibilitythateveryoneoftheelectricaldevicesonthisparticulartypeofcircuitmayberunningcontinuouslyforatleastthreehours(NECdefinitionofcontinuous),another80%of1920VAloadwasusedresultinginanapproximatemaxloadingof1536VAforeach20Aand120Vsinglepolebranchcircuit.Thesameprocessisfollowedwhenalargerthan20Asinglepolecircuitisusedorforpanelsof480/277V.ThePanelLB2asshowninfigure7hasatotalthreephaseconnectedloadof64,382VA.PanelLB2isa208Y/120Vconnectedpanelwhichmeans64,380VA/(208Vx3)=178.7A.ThisrequiresthePanelLB2mainbreakertoberatedat200A.Withaconnectedloadof64,382VA,thisrequirestheisolationtransformertoberatedat75kVA.TheNationalElectricCoderequiresthattheprimarysideofdelta-wyetransformersbeprotectedat125%ofthetransformerratedcurrent.Ifnobreakersizematchesthiscurrentvalue,thenextstandardsizeupshouldbeused.Thefollowingisanexamplecalculationofthebreakersizeneededforapanel.Fig.7.PanelLB2ExampleT−LB2=75,000VA480V×√3=90.21ABreakerSize=90.21A×1.25=112.76A(Notastandardbreakersizeso125AO.C.P)UsingthefollowingNECtable,thecurrentcarryingcon-ductorscanbesized(aswellas100%neutralwhererequired).NotethatTHHNinsulatedconductorhasbeenspecifiedandisratedat90C,butthelugsonthepanelswillberatedat75CsothecapacityoftheTHHNmustbede-ratedto75C.Thisdesignandreferenceprocedureisrepeatedforallpanelboardfeederconductorsandrequiredtransformerswhennecessary.Figures8and9arethelightingplansforthefirstandthesecondfloor.Fig.8.FirstFloorLightingPlanFig.9.SecondFloorLightingPlanAlllightingfixturesshallbewiredandcircuitedat277V(Line-Neutral)singlephasetotheH1andH2Panels,re-spectively.Occupancysensorswitchingisusedincorridorsandrestrooms.Vacancysensorswitchingisusedineveryotherroomwiththeexceptionofelectricalrooms,mechanicalrooms,communicationsrooms,janitorclosetsandotherverysmallstorageclosets.Theseexceptionscanhousenormaltoggleswitcheswithsafetyinmind.Whenworkinginautilityroom,itwouldnotbesafeforadualtechnologysensortoshutthelightsoffwhenunabletodetectaworkerkneelingbehindawaterpump.ThisprojectusedLEDlightingtoachieveitsenergyefficiency,butaprocessknownasValueEngineering(initiatedbytheclient)mayforcethelightingtoreverttoafluorescentdesign.Sotoprepareforsuchascenario,alloftheLEDlightingiscircuitedonthepanelschedulesatfluorescentlampandballastvolt-amploads.ThisprocessissafeandeffectivebecauseLEDlightingconsumesafarlesselectricload.Theseloadsareasfollows(coordinatewithlightfixturescheduleandfloorplans):A1=72VA,B1=72VA,B2=105VA,B4=72VA,E1=72VA,G2=32VA,KH1=32VA,NF1=32VA,S1=32VA,W1=72VA,XA=0VA.Theexitsigns(XA)haveanominalconsumptionoflessthanonewatt.Theexitsignsarestillwiredinaccordancewiththeirassignedbranchcircuitbutdonotfactorintoanyloadcalculationsasatypicalpractice[3],[4],[7].Figures10and11arethefirealarmplansforthefirstandthesecondfloor.Fig.10.FirstFloorFireAlarmPlanAsnotedinthetechnicalspecificationssectionofthispaper,thefirealarmsystemisaschematicrepresentationonlyandsubjecttoperformancestandardswithinthebuiltenvironment.Ifchangesareneededtobemadeupontesting,thelicensedfirealarminstallershouldcoordinatewiththeelectrical,mechanical,andfireprotectionengineers.Thefirealarmcontrolpanelisplacedinalocationthatiseasilyaccessiblebybuildingemployees/supervisor.Thefirealarmannunciatoristypicallyplacedinalobbyatthebuilding’sentrance[4],[5].Asmokedetectorshouldbeplacedin:•Roomwithfirealarmcontrolpanel;•Electricalandmechanicalroomsunlesssprinkled;•Elevatorlobbies(toinitiate”Fireman’sEmergencyRe-turn”)Fig.11.SecondFloorFireAlarmPlan•Elevatormachineroom(toinitiate”Fireman’sEmergencyReturn”andtoflash”FireHat”inelevator;•Inelevatorpitandtopofelevatorhoistway(toinitiate”Fireman’sEmergencyReturn”andtoflash”FireHat”inelevator•Oneachsideofdoorswithdoorholders.Heatdetectorsshouldbeplacedin:elevatorpit;topofelevatorhoistway;elevatormachineroomandshallactivateashunttripenclosedcircuitbreakerinNEMA3Renclosureinthemachineroomaheadofafuseddisconnectswitchfortheelevator.Manualpullstationsshouldbeplacedwithin5feetofeachexitdoorwayoneachfloor.Visiblenotificationappliances(strobelights)shouldbeplacedinconferencerooms,restrooms,classrooms,andshallberestrictedtoa50”by50”effectiverange.Combinationhornstrobesshouldbeplacedwithin15”oftheendofacorridorwithseparationnotgreaterthan100”[9].Figures12and13arethetelecommunicationplansforthefirstandthesecondfloor.TheequipmentplacedonthetelecommunicationfloorplansaredesignedforDivision26(ElectricalPower)roughinonly.Buildingownershouldsupplyalllowvoltageequipmentanddeviceswhichwillbeinstalledbyalicensedlowvoltagecontractor.Alltelecommunicationdistributionequipmentandprovisionsthatwillrequire120Vsupplyhasbeencircuitedaccordingtothatfloor’srespectivepowerplanandpanelschedule.Thewiringmethodsforalltelecommunicationsandlowvoltageequipmenthavebeenoutlinedinitsrespectivetechnicalspecifications.Figures12and13outlinetenta-tiveplacementofcabletray,wirelessaccesspoints,securitycameras,intrusiondetectiondevices,accesscardreaders,andconduitsleevesforlowvoltagecablingintorooms.Provisionshavebeendesignedtoprovidewirelessaccesstobuildingoccupantswithanestimatedusageof35-50devicesperaccesspoint.ThesecurityandaccesssystemhasbeenplacedinFig.12.FirstFloorFloorTelecommunicationPlanFig.13.SecondFloorFloorTelecommunicationPlananoptimalconfigurationtoachieveitsdesiredperformance.Finalcodecomplianceisreliantonthelowvoltageinstaller’sinstallationandadherencetobestpractices,andwillalsobearfullliabilityoftheinstallation.LightningProtectionisoneofthelaststepsthatcanbecompletedindependentofthecircuitingofthebuildingisthelightningprotectionsystem.Everyyearlightingstrikescausethousandsoffiresandbillionsofdollarsindamages.Thegeneralconceptofthesystemisverysimple.Thereareterminalsontheroofofthebuildingthataremadeoutofconductingmaterialthatthelightingstrikes.Theseterminalsareconnectedtomainconductorsthatareallinterconnectedtotheotherairterminals.Theyareallconnectedtodownconductorswhichcarryallofthecurrenttosafelydischargeintotheground.Althoughthegeneralconceptissimpletherearenumerousregulationsandrequirementsforthesystemthatmustbemet.Therearetwoclassificationsforthelightningprotectionsystems.AbuildingeitherfallsintoclassIorclassII.Theonlydifferenceinthedifferenceclassesarethematerialsused.ClassImaterialsareusedforbuildingslessthan75fthighandclassIImaterialsareusedforbuildingsgreaterthan75ft.ThebuildinginthisprojectusesclassImaterials.Thereareotherrequirementsbesidesthematerialrequirementsforthesystem.Theairterminalsmustnotbelessthan10inabovethebuilding.Mostairterminalsareplaced1ftabovetherooflevel.Therearedifferentrequirementsforthetypeofroof.Pitched,sloping,dormers,domed,androofswithchimneysorventsarealldefinedandtherequirementsareallexplicitlystatedintheNFPAcode.Thedistancebetweenairterminalsmustnotexceed20ft.Ifthebuildingexceeds50ftinwidthorlengththentherewillbeairterminalsplacedinthecenterofthebuilding.Eachterminalwillhaveatleasttwopathwaystoagroundingconductor.Eachbuildingstructuremusthaveatleasttwodownconductors.Dependingonthesizeofthebuildingtheremightberequirementsformoredownconductorsandmoreregulationsforroofandcross-runconductors.Thebuildinginthisprojecthascross-runconductorsandisgreaterthan50ftacrosssoextrarowsofairterminalsareplacedonthecenterofthestructure.Eachgroundingconductorisconnectedwithagroundingrod.Thegroundingrodlengthmustbelongerthan8ftandfreefromanynonconductivecoating.Theywillbeplacedintotheearthandextendnolessthan10ft.DisplayedBelowisthediagramforthisbuildingslightningprotectionsystem[4],[7],[9].Figure14illustratesthelightningprotectionsystem.Thisfigureshowsthatalltheairterminalsarespacednomorethan20ftapart.Everyairterminalhasatleasttwopathwaystodischargealightningstrike.Therearecross-runconductorsbecausethelengthisgreaterthan150ft.TherearegroundingconductorsatallrequiredspacinggivenintheNFPAcode.Allofthegroundingrodsareinterconnectedunderthegroundasperregulation.RefertosheetE-302forlightningprotectionsystemspecifications.MultipletypesofsoftwarewereusedduringtheprogressionofthisworksuchasMicrosoftOfficeSuite,Revit,BluebeamRevu,andAutoCADMEP.Eachsoftwareservedadifferencepurposeandhelpedachievedifferentgoals[10],[11].Revitisabuildinginformationmodelingsoftware.Itisthesoftwarethatweusedtomodelourbuildingandthecomponentsinthebuilding.Revithelpedmodelthebuildinginourdesignandplaceallitscomponents.Thishelpgeneratesheetswithallofthecomponentsandcreate3Dimages.These3Dimageswouldgenerallyonlybegeneratedifacustomerwantedanideaofhowthecompletedbuildingwouldlook.Figure15illustratesanexampleofoneoftheclassroomsinourbuildingmodeledusingtheRevit3Dview.BluebeamisanothersoftwarethatwasusedextensivelyinthisprojectinconjunctionwithRevit.BluebeamhelpedconvertthetheRevitsheetstopdffilesaswellasaddingmarkups.ThesemarkupsarecorrectionsthatweneedtogobacktoRevitandchange.Figure16isanexampleofthemarkupintheBluebeamsoftwareAutoCADMEPisanextremelyusefultoolforgeneratingFig.14.LightningProtectionSystemLegendFig.15.Revit3DClassroomViewFig.16.BluebeamCloudBubbleMarkupdetaildrawings.TherearemorefeaturesinAutoCADthatallowforeasieruseincuttinglines,creatingshapes,andexplodingimportedfiles.Figure17illustratesanexampleofusingAutoCAD.Fig.17.AutoCADExampleOneofthemajorthingsthatcanbedonetoimprovesustainabilityforabuildingstructureisenhancingenergyef-ficiency.Mostbuildingsconsumethemajorityoftheirenergyinlighting.Inordertosaveagreatdealofenergyinlighting,LEDswereusedinthedesignforthisbuilding.LEDsarefarsuperiortoCompactFluorescentlightbulbsiftheinitialcostofthefixtureisoverlooked.ThelifespanofanLEDcanbeupto10timeslongerthanthatofacompactfluorescentbulb.LEDsarealsomuchmoreefficientwiththeirelectricityusage.Theyareabletoproducethesameamountoflightwhileusinglesselectricity.AconservativeestimateforthereturnontheinitialLEDinvestmentwouldbeachievedinaround3years.PurchasingLEDlightingismoreexpensiveupfrontbutafter3yearstheenergysavedandenvironmentalimpactisconsiderablylowerthantraditionallighting.ASHRAEsetsastandardforthemaximumamountofpowerthatisallowedpersquarefootinanytypeofbuilding.Inthisproject,thegoalwassettoexceedthisstandardinordertobeasustainableproject.Alloftheroomsaresub-stantiallyundertherequirement.ThisbecomesanachievablegoalsimplybyusingLEDsinsteadoftraditionalfluorescentlightingfixtures.Dependingonthebuildingsize,areturnontheinvestmentcouldachieveinfewyears.LEDsalsogiveofflessheatandaremoreenvironmentalfriendlythanthetradi-tionalfluorescentbulbs.Figure18isthepowerrequirementforoneoftheclassroomsinthedesignedbuilding.Thesimulatedpowerusageforthisroomwas0.57Wpersquarefoot.ThisislessthanhalfofthemaximumthatisallowedperASHRAEwithoutreducingthelighting.Figure19a3Disometricviewofthefinalbuildingdesignthatdisplaysjustalltheelectricalcomponentsandlights.III.CONCLUSIONInthispaper,anenergyefficientelectricaldesignofahighereducationbuildingwasdesignedhighlightingtjelayoutforlowvoltagesystems.Asystematicapproachwasconsideredtotackleeachportionofthepr