SOME OUTSTANDING TITLE 24 ISSUES FOR文档格式.docx

SOME OUTSTANDING TITLE 24 ISSUES FOR文档格式.docx

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⏹HIGH-RISERESIDENTIALSHGCREQUIREMENTS&

HEATINGENERGY:

The2001StandardsadoptedrelativelylowSHGCsforHigh-RiseResidentialbuildings,evenincoastalclimatezones.AmorerigorousanalysisshouldbeperformedtoseewhethertheselowSHGCsactuallyproducebuildingswithlowerenergyusethanbuildingswithmoremoderateSHGCs,thatwouldreceivemorebeneficialsolarheatgaininwinter（thusloweringheatingenergyuse）.

⏹SHGCREQUIREMENTSANDPERFORMANCECOMPLIANCE:

The2001StandardsreducedtheallowedSHGCrequirementsforallbuildingtypes.WhentheprescriptivestandardhasalowSHGCrequirement,asitnowdoes,performancecomplianceneedtoberigorouslytestedtodeterminewhetherthelowSHGCrequirementiscausingthestandardstobeweakenedwhencomplyingundertheperformancemethod.ThiscouldoccurbecausetheStandardBudgetwillassumeabuildingwithlowsolarheatgaininwinter.AproposedbuildingwithhigherSHGCwillhavelowerenergyconsumptioninwinter.

⏹VARYRESIDENTIALSHGCREQUIREMENTS?

:

ConsideradoptingahigherSHGCrequirementformulti-unitresidentialbuildingsthatuseacentralheatingsystemandhavenocoolingsystem.Becauseitisdifficulttoaddmechanicalcoolingtosuchabuildingtypewhenithascentralheating,itisverylikelythathigherSHGCglasswillsavemuchmoreheatingenergythanitwillcauseanincreaseincoolingenergy.

⏹LOW-RISERESIDENTIALFENESTRATIONTHERMALEFFICIENCY:

ReevaluatethefenestrationU-Valuerequirement.NonmetalframesandLowEglasspriceshavegonedownsincethepreviouseconomicevaluationofresidentialfenestrationefficiencyrequirements.

⏹LOW-RISERESIDENTIAL“STANDARD”WATERHEATER:

Considerallowingtanklessgas-firedwaterheaterswithelectronicignitiontomeettherequirementsofa“standard”system.Ifthesesystemsareasenergy-efficientasthemanufacturer’sclaim,Title24shouldnotcreateanimpedimenttotheiruse.Unlessitimposesanenergypenalty,allowanynumberoftanklesssystems（withelectronicignitions）perresidencetomeetthedefinitionof“standard”system（unlessthesystemhasrecirculation）.

IntheRFQfortheaconsultantforthe2003/2005Standards,theCECcorrectlypointsoutthathigh-efficiencystoragewaterheaters（40and50gallons）costaboutthesameaslow-efficiencywaterheaters,andthereforeacttoweakentheresidentialstandards.TheRFQsuggestsapossibleremedyofrequiringwaterheatingenergyrequirementstobemetindependentlyofthespaceheatingandcoolingenergybudget.Whilethisremedyisdefinitelyworthconsideration,itwouldnotproduceanincentivetousetanklessgaswaterheaters.CouldtheACMrulesdivorcethewaterheaterenergyfromthespaceconditioningenergywhenastorage-typewaterheaterisused,butcontinuethecurrentpracticeofcombiningallenergywhenatanklesswaterheaterisused?

Orperhapsanothertypeofincentivecouldbeadoptedtoencourageuseoftanklesswaterheaters.

⏹NONRESWATERHEATING:

Regulatenonresidentialservicehotwatersystems.Perhapsanygas-firedsystemshouldbeacceptable.However,ifanelectricsystemisproposed,performancecompliancewouldberequired.TheStandardwaterheaterenergywouldbebasedonagas-firedsystemofthesamecapacity.

⏹HEATRECOVERY（ResandNonres）:

Requireventilationairheatrecovery（e.g.air-to-airheatexchanger）inbuildingsorspaceswithhighOSAdesign（e.g.above25%ofHVACsystemcfm）,andcertainamountofoperatinghours（e.g.min.of40/week）.SomeresidentialbuildingsdohavehighOSArequirements,likeconvalescenthomes.

INITIATIVESTOREDUCEPEAKCOOLINGLOADS:

⏹NONRESWESTGLAZING:

Limitwestfacingglassareato40%ofthewestGrossWallArea（prescriptiveapproach）.Currently,thestandardsonlylimitoverallglassareas.Theperformancebudgetwouldbebasedonthesamerequirement.

⏹RESIDENTIALWESTGLAZING:

PrescriptivePackagecompliancedoesnotregulatewestglassarea.Consideralimit（perhaps30or35%oftotalfenestrationarea?

）.NotethatunderPerformancecompliance,thereismodestregulationbyorientationinthattheallowedbudgetisbasedonequalareasoffenestrationinallfourcardinaldirections.

⏹RES&

NONRESACEFFICIENCY:

Increaseminimumefficienciesforairconditioningequipment.

NONRESACSIZING:

Mandatemaximumairconditioningsizing,basedonprescribedloadsanalysis,forbothResidentialPrescriptiveandPerformancecompliance,andforNonresidentialPerformancecomplianceapproach（asiscurrentlyrequiredundertheNonresidentialPrescriptiveapproach）.

NONRESEVAPORATIVECOOLING:

Developacompliancecredittoencouragetheuseofevaporativecoolersinsteadofconventionalairconditioners.

NONRES:

ToreducetheincidenceofACsystemoversizing,requirethatthecoolingloadcalculationaccountforstructuralshadingofthefenestration（e.g.overhangs,fixedawnings）.

INITIATIVESTOREDUCEBOTHHEATING&

COOLINGLOADS:

⏹RESFENESTRATIONAREA:

Developmethodforreducingtheprescriptivefenestrationareaallowanceforlargerbuildings（single-familyaswellasmulti-family）.Underthecurrentfenestrationallowanceapproach,basedsolelyonfloorarea,verysmallbuildingsarepenalized,andlargerbuildingsgetanunduecredit（i.e.theredesignfenestrationareaisusuallylowerthantheprescriptivefenestrationareaallowance）.

Onepossibleremedyistorestructurethebasicpackageglazingareaallowancetoreflectacombinationoffloorareaandperimeter.APPENDIXAexplainsaproposalforasingleformulatodetermineallowedfenestrationareaforalllow-riseresidentialbuildingtypes.Thisformularesultsinsimilarglazingallowancesforaveragesizehomesasthecurrentformula,reducestheallowedfenestrationareaofverylargehomes,andbringstheglazingallowanceofmulti-unitbuildingsinlinewithactualdesignpractice,withouthavingtojustifyvariousformulasfordifferentsizesortypesofresidentialbuildings.

⏹RESMULTI-FAMILYPRESCRIPTIVEGLASSAREA:

Shouldarestructuringofthefenestrationallowanceforallresidentialbuildings,assuggestedabove,notbefoundacceptable,considerreducingthefenestrationallowanceforlargermulti-familyresidentialbuildings.Ihavefoundthatlargermulti-familybuildingsoftenhaveglassareasofaround10to13percentoftheC.F.A.ThecurrentStandardsgivemulti-familybuildingsanunwarranted“credit”underperformancecompliance.

Encourageheatandcoolrecoveryfromexhaustairtotemperventilationair（air-to-airheatexchanger）.

MISCELLANEOUSNONRESIDENTIALSTANDARDSEFFICIENCYISSUES:

⏹NONRESIDENTIALPERFORMANCEREFERENCEHVACSYSTEM:

TheselectionofthereferenceHVACsystem（usedtodeterminetheStandardBudget）shouldbebasedontheconditionedfloorarea,buildingvolume,oracombinationofoneofthesefactorsandthenumberofstories,insteadofbasingitsolelyonthenumberofstories.Therearemanyverylargethreestorybuildings,whereaVAVreferencesystemwouldbeappropriate;

conversely,somefourstorybuildingsmaybeverysmall,dependingontheirfootprint.OneexampleofaverylargethreestorybuildingistheMosconeCenterAddition.Itisathreestorybuilding,withveryhighfloor-to-ceilingdistances.Theperformancecompliancereferencesystemwasasingle-zoneconstantvolumetype,butthebuildingappropriately（forit'

svolume）usesabuilt-upVAVsystem.TheTitle24StandardBudgetallowedalightingLPDthatismoderatelyhigherthantheprescriptiveLPD.

⏹NONRESIDENTIALSKYLIGHTS:

Revisitcurbmodelingissue.Tosimplifyskylightmodeling,perhapscurbsshouldnotbeincludedineithertheskylightorroofmodeling.Instead,curbscouldeitherhaveamandatoryminimuminsulationrequirement,ortheNonresidentialManualcouldsimplyemphasizethatallcurbsmustbemodeled（theENV-2formcouldhaveacheckboxforcurbs,asareminderthattheyneedtobemodeled–ormeetamandatoryminimuminsulationlevel）

⏹EXTENDNONRESIDENTIALLIGHTINGREQUIREMENTStoFOLLOWINGOCCUPANCIES:

♦RegisteredHistoricbuildings.

♦IOccupancybuildings（excludingsurgeryrooms）.

♦Buildingsmaintainedoutsidethehumancomfortrange.

♦Unconditionedbuildings.

⏹EXTENDNONRESIDENTIALENVELOPEREQUIREMENTStoFOLLOWINGOCCUPANCIES:

♦IOccupancybuildings.

⏹NONRESIDENTIALLIGHTING

♦ELIMINATE“RETAIL”OCCUPANCYTYPE:

Eliminate“Retail”fromthelistofbuildingTypeofUsesandPrimaryFunctionAreas.Theuseoftheword“retail”intheStandardscausesmuchcomplianceconfusion,asitisusedtojustifyretaillightingallowancesfornon-retailtenantsinso-called“retailbuildings”.Inplaceof“retail”,defineboth“ShoppingCenterBuilding”and“MerchandiseSales”.ShoppingCenterBuildingwouldbedefinedasabuildingthatcouldbeoccupiedbyoffice-typeoperations,aswellasbytenantsprovidingservices（suchasrealtyandpackaging）andtenantssellingmerchandise.UnleasedspaceinShoppingCenterBuildingswouldreceivethesamelightingpowerallotmentasofficespace.SpaceleasedforthepurposeofMerchandiseSaleswouldgetanappropriatelygreaterallotment.Typically,requiringunleasedspacetocomplyatanofficeleveloflightingisnotahardship,forthefollowingreasons:

A）Manydevelopersof“plainvanilla”retailspaceonlyinstalloffice-typelightinganyway;

B）Retailtenantsthatmoveinto“plain