ASHRAE-Standard-90.1-2010

EngineersNewsletterprovidinginsightsfortoday’shvacsystemdesigner©2010Trane,abusinessofIngersollRand.Allrightsreserved.1volume39–3ASHRAEStandard90.1-2010UpdatestomechanicalsystemmandatoryandprescriptiverequirementsASHRAEStandard90.1-2010issimply90.1-2007,withtheincorporationofmorethan100approvedaddenda,52ofwhichaffectmechanicalsystemsandwillbethefocusofthisarticle.Othersignificantchangesweremadetothescope,lighting,buildingenvelopeandmodelingsectionsofthestandard,whichwillaffectloadcalculationsandequipmentsizing.Theaddendathataffectmechanicalsystemscanberoughlygroupedintothefollowingareas:•Equipmentefficiency�Systemdesignandcontrolrequirements–Waterside–Outdoorair–AirsideThesechangesareoutlinedinthefollowingsections.EquipmentEfficiencyChangesThefollowingisasummaryofupdatestotheequipmentefficienciesrequiredby90.1-2010.Airconditionersandheatpumps.Efficienciesforairconditionersandheatpumpshavebeenimprovedsubstantiallyinrecentyears.Infact,whencomparedtothe1989standard,thereisapproximatelya17percentEnergyEfficiencyRatio(EER)improvementinthelargersizesand30percentinthe5-to20-toncategory.Forsmall,lessthan5-ton,equipmentthechangeisapproximately34percentSeasonalEnergyEfficiencyRatio(SEER)improvement.EquipmentschedulesnowincorporateanewtermcalledIntegratedEnergyEfficiencyRatio(IEER).ThisnewmetricwasdevelopedforunitaryproductstoreplaceIntegratedPartLoadValue(IPLV)andencouragedesignsthathavebetterpart-loadperformance.(AddendumS)The2010versionofASHRAEStandard90.1,EnergyStandardforBuildingsExceptLow-RiseResidentialBuildings,willbepublishedthisfall.Significantly,thegoalofASHRAEStandard90.1-2010wastoachieve30percentenergy-costsavingscomparedto90.1-2004(aggregatedacross16buildingtypesin17climatezones).Thisnewsletterprovidesanoverviewofthemechanicalchangesthatpertaintoheating,ventilationandair-conditioning.2TraneEngineersNewslettervolume39–3providinginsightsfortoday’sHVACsystemdesignerSingle-zoneVAV.AsofJanuary1,2012,unitaryequipment110,000Btuh(9.2tons)orlargerservingasinglezonemustprovidemeanstoreducefanspeedtotwo-thirdsorlessatloadsbelow50percent.Thiscanbeaccomplishedbytwo-speedorvariable-speedfans.Chilled-waterair-handlingunitshaveasimilarrequirement(effectiveJanuary2010);see“VAVrequirementsforchilledwaterair-handlingunitsservingasingle-zone,”p.7.Thelow-speedairflowcanbethelargerofthelimitstatedaboveortheASHRAE62.1ventilationrequirementforthezone.Outdoorairmeasurementoracompensatingdamperwillbenecessaryforproperventilationatreducedspeed.Dischargeairtemperaturesensorsormultiplestagesofcompressionmaybenecessaryforpropercontroloftheunit.(AddendumN)Water-cooledandevaporativelycooledairconditionersandheatpumps.Newfull-loadefficiencyrequirementsare3to5percentmorestringentasofJune2011,withIEERincreasesof5to13percent.(AddendumCO)Inaddition,two-positionvalvesarenowrequiredonwater-cooledairconditionersaswellasonwater-loopheatpumps.Seefurtherdiscussionin“Waterside,”p.3.(AddendumAK)Packagedterminalairconditionersandheatpumps(PTAC/PTHP).AsofOctober2012,PTACsandPTHPswillberequiredtomeetnew,aggressiveefficiencylevels.(AddendumBW)Thedefinitionofnon-standardsizewasalsoaddedsothatstandard-sizedunitsinnewconstructionmustmeetadifferentefficiencylevelthanreplacementunitshavingtofitintoexistingwallsleeves.(AddendumT)Water-to-waterheatpumps.Thewater-to-waterheatpumpasaheatingorcoolingdevicenowfallswithinthescopeofthestandard.Therequiredefficiencylevelsvarybyapplication(suchaswatersource,groundwatersource,groundsource)tocorrespondwiththeratingtemperaturestypicalforthoseapplications.(AddendumBG)Computerroomairconditioners(CRAC).Thescopeof90.1hasbeenexpandedtoincludesystemsusedincommercialprocesscoolingapplications.(AddendumAQ)Asaresult,thereisanewclassofcoveredproduct:computerroomairconditioners,orCRACunits.ASHRAE127isthereferencedtestprocedure.TheASHRAEtestprocedurehasdefinedatermcalledSensibleCoefficientofPerformance(SCOP).SCOP-127calculatesefficiencyatconditionsmorereflectiveofthemostlysensiblecoolingthatoccursindatacentersandcomputerrooms.(AddendumBU)Variable-refrigerant-flow(VRF)multi-splits.Whileminisplitshavebeencoveredby90.1formanyyearsandcertifiedtoAHRI210/240,asimilarclassofequipmentcalledamulti-splitorVRFsystemwaspreviouslynotcovered.ThistypeofsplitsystemhasmultipleindoorDXfancoilssharingacommoncompressorandcondenser.TheAHRI1230testprocedureisnowpublishedandthereareefficiencyrequirementsforthesesystems.TheIEERrequirementsgetmorestringentinJuly2012.VRFsystemscanincludeheatrecoverythrougharefrigerant-to-waterheatexchanger.ThereisaspecialcategoryineachsizeforVRFsystemswithheatrecovery.(AddendumCP)Note:Aswefinalizedthisnewsletter,AHRIwasabouttoreleaseacertificationprogramforVRFmulti-splits.Chillers.SinceJanuary2010,AddendumMhasbeenineffect.Thebigchangewastheadditionofanalternativecompliancepathforwater-cooledchillers.OnepathhasamorestringentIPLV(partload)requirement,whiletheotherhasamorestringentfull-loadkW/tonrequirement.Eachpathhasbothafull-loadandapart-loadmetrictomeet.(AddendumM)Glycolorbrineinchillers.Otherchangestothechillersectiontar