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專業(yè)：班級：姓名：指導(dǎo)老師：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.譯文:HPAC工程，2010年12月1日辦公室塔水力更新在芝加哥的一個辦公樓更換加熱或冷卻廠采用電制冷機(jī)和燃?xì)忮仩t，坐落在芝加哥循環(huán)，邁克爾A。Bilandic大廈是一座21層的辦公大樓，服務(wù)國家伊利諾伊州的機(jī)構(gòu)，包括伊利諾伊州最高法院。

1989年，現(xiàn)有的建筑結(jié)構(gòu)是內(nèi)臟和裝修。當(dāng)時，增加了一個新的頂層房子主要的機(jī)械設(shè)備，包括三個燃?xì)猓瑑杉壩帐街评錂C(jī)加熱器。每個單位的600噸的冷卻和7200加熱MBH產(chǎn)量。專用的20馬力的雙細(xì)胞冷卻塔高或低轉(zhuǎn)速風(fēng)扇被安裝在屋頂上。從那時起，與同等容量的模塊化電動式冷水機(jī)組和雙工水力燃?xì)忮仩t冷水機(jī)組加熱器已被替換。的更新，提高設(shè)備的可靠性，易于維護(hù)，并在運(yùn)作的第一年，在測量熱能源的使用節(jié)省了15％。出于與舊現(xiàn)有的水力系統(tǒng)顯然需要更新。安裝在21樓附近的冷水機(jī)組的加熱器，四個主要的加熱管和冷卻泵的電源為整個建筑的多個變風(fēng)量（VAV）空氣處理機(jī)組及周邊輻射上限線圈。四個30馬力的主要采暖泵和4個40馬力的冷凍水泵送入水力返回水管。每個類型有三個注入各自的冷水機(jī)組加熱器，而第四加熱和冷凍水水泵提供手動待機(jī)責(zé)任。同樣，4個100馬力的冷凝器，水泵（因為這已與40馬力的泵取代）發(fā)生在水供應(yīng)冷卻塔頭，泵入冷卻水吸收式制冷機(jī)，熱冷凝水返回到一個專用的降溫塔。

由于常年使用，一個冷水機(jī)組加熱器分手后，只有約16年的使用壽命，并成為報廢。該建筑繼續(xù)維持在剩下的兩個功能，但不再從應(yīng)急待命能力受益制冷機(jī)加熱器本身的舒適。大樓的設(shè)施管理人員緊急更換了新的單位，在一次舊吸收式制冷機(jī)加熱器。梅爾文科恩和Associates公司選擇了由伊利諾伊首都發(fā)展局州準(zhǔn)備投標(biāo)和施工設(shè)計文件。西甲工程師在芝加哥被選為提供調(diào)試。

今后的挑戰(zhàn)

吸收式制冷機(jī)加熱器是沉重的，笨重的機(jī)器，重達(dá)40,000磅每。更換冷水機(jī)組的爐建設(shè)的21拆解成較小的操縱件，由直升機(jī)單位需要的地板上，創(chuàng)造了在屋頂?shù)拇箝_放，并取得特別許可證，到繁華的街道，周圍的建筑施工期間多次接近。此外，新吸收的單位沒有本地和需要至少6個月的籌備時間，才可以從日本運(yùn)。

由于手頭的任務(wù)的緊迫性，這些場景，令人望而生畏。此外，吸收式制冷機(jī)的電熱水器沒有得到很好的著名的熱效率。因此，需要一種新的方法。一種選擇是使用模塊化的電動式冷水機(jī)組和組合式燃?xì)忮仩t，可以通過建設(shè)的貨運(yùn)電梯運(yùn)輸。雖然方便，取得了大量新的頂層所需的電功率以及保證所有舊吸收單位騰出的空間內(nèi)所需的模塊化設(shè)備的適當(dāng)?shù)呐浜希呀?jīng)很難。然而，建設(shè)調(diào)查表明，現(xiàn)有的480-V電動交換機(jī)在地下室有足夠的物理和電氣容量為新的電力需求。它也是可行的運(yùn)行新的動力立管從地下室開關(guān)室21樓，并提供足夠的存儲空間，以擴(kuò)大現(xiàn)有冷水機(jī)組加熱器室，如有必要。這種策略一般是可以接受的項目團(tuán)隊。最終的設(shè)計與施工

三個老的氣體吸收式制冷機(jī)，熱水器每個被替換（連續(xù)在三個不同的階段）與現(xiàn)有的備件800安培狂奔在地下室的現(xiàn)有開關(guān)壓力開關(guān)的八個模塊化電動式冷水機(jī)組的銀行擔(dān)任大會。電力饋線延長從每個螺栓壓力開關(guān)模塊化冷水機(jī)組銀行21樓。

在49英寸28英寸69英寸和2200磅，冷水機(jī)組具有兩個35噸，R-410A的渦旋式壓縮機(jī)（具有獨立的制冷回路）和不銹鋼板式換熱器。每個制冷機(jī)銀行大會是伴隨著兩個全雙工更換暖氣燃?xì)忮仩t。在39英寸由41英寸85英寸和2400磅，鍋爐2640-MBH輸出功能和可變頻率驅(qū)動器（VFD）鼓風(fēng)式燃燒器。

位于同一地區(qū)，原先由舊燃?xì)馕帐街评錂C(jī)加熱器占領(lǐng)三個modular-chiller/duplex-boiler集會。沒有額外的空間是必要的，所有