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专业：班级：姓名：指导老师：HPACEngineering，Dec1,2010Office-TowerHydronicUpdateTheheatingorcooling-plantreplacementataChicagoofficebuildingfeatureselectricchillersandgasboilers,LocatedintheChicagoLoop,theMichaelA.BilandicBuildingisa21-storyofficetowerservingStateofIllinoisagencies,includingtheIllinoisSupremeCourt.In1989,theexistingbuildingstructurewasguttedandrenovated.Atthattime,anewtopfloorwasaddedtohousemajormechanicalequipment,includingthreegas-fired,two-stageabsorptionchiller-heaters.Eachunithadanoutputof600tonsofcoolingand7,200mbhofheating.Dedicateddual-cellcoolingtowerswith20-hphighorlow-speedfanswereinstalledontheroof.Sincethen,thechiller-heatershavebeenreplacedwithequivalent-capacitymodularelectricchillersandsetsofduplexhydronicgasboilers.Theupdateresultedinenhancedequipmentreliability,easiermaintenance,and,duringthefirstyearofoperation,a15-percentsavingsinmeasuredthermal-energyuse.OutWiththeOld

Theexistinghydronicsystemclearlyneededanupdate.Withpumpsmountedonthe21stfloorinthevicinityofthechiller-heaters,four-pipeprimaryheatingandcoolingmainsservedmultiplevariable-air-volume(VAV)air-handlingunitsandperimeterradiantceilingcoilsthroughoutthebuilding.Hydronicreturnmainsfedintofour30-hpprimaryheatingpumpsandfour40-hpchilled-waterpumps.Threeofeachtypepumpedintotherespectivechiller-heaters,whilethefourthheatingandchilled-waterpumpsprovidedmanualstandbyduty.Likewise,four100-hpcondenser-waterpumps(whichsincehavebeenreplacedwith40-hppumps)tookinwaterfromthecooling-towersupplyheader,pumpedcoolwaterintoanabsorptionchiller,andreturnedhotcondenserwatertoadedicatedcoolingtower.Becauseofyear-rounduse,onechiller-heaterbrokedownafteronlyabout16yearsofusefullifeandbecameunserviceable.Thebuildingcontinuedtosustainitselfcomfortablyontheremainingtwofunctionalchiller-heatersbutnolongerbenefitedfromemergencystandbycapacity.Thebuilding'sfacility-managementstaffurgentlyreplacedtheoldabsorptionchiller-heaterswithnewunits,oneatatime.MelvinCohenandAssociatesInc.waschosenbytheStateofIllinoisCapitalDevelopmentBoardtopreparedesigndocumentsforbidandconstruction.PrimeraEngineersinChicagoChallengesAhead

Absorptionchiller-heatersareheavy,bulkymachinesthatweighupto40,000lbeach.Replacingthechiller-heatersonthebuilding's21stfloorrequireddisassemblingtheunitsintosmallerpiecesforriggingbyhelicopter,creatingalargeopeningintheroof,andprocuringspecialpermitstoclosedowntownstreetsaroundthebuildingonseveraloccasionsduringtheconstructionperiod.Further,thenewabsorptionunitswereunavailablelocallyandrequiredaminimumofsixmonthsofleadtimebeforetheycouldbeshippedfromJapan.Giventheurgencyofthetaskathand,thesescenariosweredaunting.Additionally,absorptionchiller-heatersarenotwell-knownforthermalefficiency.Therefore,anewapproachwasneeded.Oneoptionwastousemodularelectricchillersandmodulargasboilersthatcouldbetransportedviathebuilding'sfreightelevator.Althoughconvenient,obtainingthevastamountofnewelectricpowerneededonthetopflooraswellasguaranteeingaproperfitforalloftherequiredmodularequipmentwithinthespacevacatedbytheoldabsorptionunits,wouldhavebeendifficult.However,buildingsurveysindicatedthatexisting480-velectricswitchboardsinthebasementhadthesufficientphysicalandelectricalcapacityavailabletoservenewpowerneeds.Italsowasfeasibletorunnewpowerrisersfromthebasementswitchgearroomuptothe21stfloor,andsufficientstoragespacewasavailabletoexpandtheexistingchiller-heaterroomifnecessary.Thisstrategygenerallywasacceptabletotheprojectteam.FinalDesignandConstruction

Thethreeoldgas-absorptionchiller-heaterseachwerereplaced(inthreedistinctcontiguousphases)withabankassemblyofeightmodularelectricchillersservedbyexistingspare800-ampboltedpressureswitchesinthebasement'sexistingswitchgear.Powerfeederswereextendedfromeachboltedpressureswitchtoamodularchillerbankonthe21stfloor.At28in.by49in.by69in.and2,200lb,thechillersfeaturetwo35-ton,R-410ascrollcompressors(withindependentrefrigerantcircuits)andstainless-steelplateheatexchangers.Eachchiller-bankassemblywasaccompaniedbytwoduplexgas-firedboilersforreplacementheating.At39in.by41in.by85in.and2,400lb,theboilersfeature2,640-mbhoutputandavariable-frequency-drive(VFD)forced-draftburner.Thethreemodular-chiller/duplex-boilerassembliesarelocatedinthesameareapreviouslyoccupiedbytheoldgas-absorptionchiller-heaters.Noadditionalspacewasrequired,andalloftheequipmentwasabletofitproperlywithoutunduecongestion.MostoftheequipmentwaspurchasedwithinNorthAmerica.OtherImprovements

Manyotherimprovementsweremadetothebuilding'smechanicalsystems,suchas:Replacingtheexistingcooling-towertargetnozzleswithsmallerorificenozzlestohelpdistributethereducedcondenser-waterflowrequiredbythenewchillerbanks.ReplacingtheexistingHVACcontrolsystem'solddirect-digital-control(DDC)panelsandsensorswithastate-of-the-artsystemthatutilizestheinteroperableopenBACnetprotocol.Replacingthedomestic-watertriplexhousebooster-pumpsystemwithamodernpackagethatincludesVFDcontrolsforeachpump.Replacing12agedprimaryhydronicpumpswithupdatedpumpstosuitnewsystemrequirements.Replacingthecooling-towerchemical-feedsystemandfinesidestreamfiltersattheheatingandcoolinghydronicmainswithnewequipmentthatutilizespipe-corrosion-monitoringhardware.Replacinganexisting3,000-ampbuilding-lightingswitchboardwithold-stylecircuitbreakers(whichhadnotbeenremovedduringthe1980srenovation)withanewswitchboardcontainingmodernswitchandfuseconstructionforbetterreliability.Energy-SavingFeatures

Evenproducingthesameamountofcooling,thenewelectricchillersuseandrejectone-thirdlessthermalenergycomparedwiththeoldabsorptionchillers.Therefore,thecondenserflowwasreducedsharply,andthecooling-towerfansdidnothavetoworkquiteashard.Atpartload,ascrollmodularelectricchillerusesupto25-percentlesselectricalenergythanitdoesatfullload.Therefore,multiplechillercompressorsateachchillerbankcanbecontrolledautomaticallyinalead-lagmannerbyafactory-furnishedmastercontrolpanel(onepanelperbank)tohelpmaximizechilleroperatingefficiencyatpartload.Unlikeanabsorptionchillerthatmustreceivecondenserwateratasteady85°F,theoperatingefficiencyofascrollmodularchillerimprovessignificantlyatlowercondenser-water-supplytemperatures.Therefore,thebuilding'scooling-tower-fanoperationwasprogrammedtoresetcondenser-water-supplytemperaturetowithin8°Foftheprevailingoutdoorwet-bulbtemperature.Thesixnewmodularboilersaresetforautomaticlead-lagoperation,injectingheatintothebuilding'sheating-watersupplymainasneededtomaintainsupply-maintemperature.Aninlinepumpandthree-waycontrolvalveateachmodularboilerensureaminimum140°Fboilerentering-watertemperaturetopreventflue-gascondensation.Thenewboilersprovide88-percentthermalefficiencyatfullloadvs.the80-percentefficiencyoftheoldabsorptionchiller-heaters.Eachcooling-and-heating-bankassemblyincludesenergymeterstomonitoroperatingefficiency(kilowattspertonforthecoolingbankandthermalefficiencyfortheheatingbank).Parametersaredisplayedatthebuilding-automationfront-endcomputersystem.Adegradingperformanceovertimesignalsalertsforcriticalmaintenanceneeds,suchasheat-exchangercleaningoragas-combustiontune-up.Back-flushvalvesalsowereaddedtoeachcondenser(plateheatexchanger).First-YearPerformance

Ayear-by-yearcomparisonofelectricandgasutilitybillsbeforeandafterprojectconstructionshowsthebuilding'sgasconsumptionwasreducedby29percentandelectricityconsumptionwentupbyonly1percent.Keepinmindtheoldchiller-heaterequipmentoperatedmostlyusingnaturalgas.Whilethetotalofannualheatingandcoolingdegree-dayswasnearlythesame,thegrossenergyconsumptiononaBritish-thermal-unitbasiswentdownbynearly15percent.Conclusion

Thebuilding'sdesignworkbeganinearly2007,andprojectconstructionwascompletedbythemiddleof2009.Thebuildingremainedinfullnormaloperationthroughouttheproject.Theconstructionworkwascompletedsmoothlyandontime,withnosignificantglitches.Theconstructioncostswereabout25-percentbelowtheStateofIllinoisCapitalDevelopmentBoard'soriginalbudgetandincludedcostsforcorrectingseveralpreviouslyundiscoveredconditions.Thebuildingcanbekeptcomfortablewithjustonebankofboilersandnomorethantwobanksofchillers.Therefore,standbyequipmentcapacityissignificant.Thenewreplacementplantiseasytomaintainandwillcontinuetorealizesubstantialenergysavingsinthefuture.译文:HPAC工程，2010年12月1日办公室塔水力更新在芝加哥的一个办公楼更换加热或冷却厂采用电制冷机和燃气锅炉，坐落在芝加哥循环，迈克尔A。Bilandic大厦是一座21层的办公大楼，服务国家伊利诺伊州的机构，包括伊利诺伊州最高法院。

1989年，现有的建筑结构是内脏和装修。当时，增加了一个新的顶层房子主要的机械设备，包括三个燃气，两级吸收式制冷机加热器。每个单位的600吨的冷却和7200加热MBH产量。专用的20马力的双细胞冷却塔高或低转速风扇被安装在屋顶上。从那时起，与同等容量的模块化电动式冷水机组和双工水力燃气锅炉冷水机组加热器已被替换。的更新，提高设备的可靠性，易于维护，并在运作的第一年，在测量热能源的使用节省了15％。出于与旧现有的水力系统显然需要更新。安装在21楼附近的冷水机组的加热器，四个主要的加热管和冷却泵的电源为整个建筑的多个变风量（VAV）空气处理机组及周边辐射上限线圈。四个30马力的主要采暖泵和4个40马力的冷冻水泵送入水力返回水管。每个类型有三个注入各自的冷水机组加热器，而第四加热和冷冻水水泵提供手动待机责任。同样，4个100马力的冷凝器，水泵（因为这已与40马力的泵取代）发生在水供应冷却塔头，泵入冷却水吸收式制冷机，热冷凝水返回到一个专用的降温塔。

由于常年使用，一个冷水机组加热器分手后，只有约16年的使用寿命，并成为报废。该建筑继续维持在剩下的两个功能，但不再从应急待命能力受益制冷机加热器本身的舒适。大楼的设施管理人员紧急更换了新的单位，在一次旧吸收式制冷机加热器。梅尔文科恩和Associates公司选择了由伊利诺伊首都发展局州准备投标和施工设计文件。西甲工程师在芝加哥被选为提供调试。

今后的挑战

吸收式制冷机加热器是沉重的，笨重的机器，重达40,000磅每。更换冷水机组的炉建设的21拆解成较小的操纵件，由直升机单位需要的地板上，创造了在屋顶的大开放，并取得特别许可证，到繁华的街道，周围的建筑施工期间多次接近。此外，新吸收的单位没有本地和需要至少6个月的筹备时间，才可以从日本运。

由于手头的任务的紧迫性，这些场景，令人望而生畏。此外，吸收式制冷机的电热水器没有得到很好的著名的热效率。因此，需要一种新的方法。一种选择是使用模块化的电动式冷水机组和组合式燃气锅炉，可以通过建设的货运电梯运输。虽然方便，取得了大量新的顶层所需的电功率以及保证所有旧吸收单位腾出的空间内所需的模块化设备的适当的配合，已经很难。然而，建设调查表明，现有的480-V电动交换机在地下室有足够的物理和电气容量为新的电力需求。它也是可行的运行新的动力立管从地下室开关室21楼，并提供足够的存储空间，以扩大现有冷水机组加热器室，如有必要。这种策略一般是可以接受的项目团队。最终的设计与施工

三个老的气体吸收式制冷机，热水器每个被替换（连续在三个不同的阶段）与现有的备件800安培狂奔在地下室的现有开关压力开关的八个模块化电动式冷水机组的银行担任大会。电力馈线延长从每个螺栓压力开关模块化冷水机组银行21楼。

在49英寸28英寸69英寸和2200磅，冷水机组具有两个35吨，R-410A的涡旋式压缩机（具有独立的制冷回路）和不锈钢板式换热器。每个制冷机银行大会是伴随着两个全双工更换暖气燃气锅炉。在39英寸由41英寸85英寸和2400磅，锅炉2640-MBH输出功能和可变频率驱动器（VFD）鼓风式燃烧器。

位于同一地区，原先由旧燃气吸收式制冷机加热器占领三个modular-chiller/duplex-boiler集会。没有额外的空间是必要的，所有