Air-Cooled Series R Helical-Rotary Liquid Chiller - Trane

Features and BenefitsTracer optimization softwarecontrols operation of the requiredequipment and accessories to easilymove from one mode of operationto another. For example: even withice-storage systems, there arenumerous hours when ice is neitherproduced nor consumed, but saved.In this mode, the chiller is the solesource of cooling. For example, tocool the building after all ice isproduced but before high electric aldemand charges take effect, Tracersets the air-cooled chiller leavingfluid set point to its most efficientsetting and starts the chiller, chillerpump, and load pump.When electrical demand is high, theice pump is started and the chilleris either demand limited or shutdown completely. Tracer controlshave the intelligence to optimallybalance the contribution of the iceand the chiller in meeting thecooling load.The capacity of the chiller plant isextended by operating the chillerand ice in tandem. Tracer rationsthe ice, augmenting chiller capacitywhile reducing cooling costs. Whenice is produced, Tracer will lowerthe air-cooled chiller leaving-fluidset point and start the chiller, iceand chiller pumps, and otheraccessories. Any incidental loadsthat persists while producing icecan be addressed by starting theload pump and drawing spentcooling fluid from the ice storagetanks.For specific information on icestorage applications, contact yourlocal sales office.8RLC-PRC005-E4

OptionsHigh Efficiency/Extra Efficiency andPerformance OptionThese options provide oversizedheat exchangers with two purposes.One, it allows the unit to be moreenergy efficient. Two, the unit willhave enhanced operation in highambient conditions.Low-Temperature BrineThe hardware and software on theunit are factory set to handle lowtemperature brine applications,typically below 5 C [41 F].Ice MakingThe unit controls are factory set tohandle ice making for thermalstorage applications.Tracer Summit CommunicationInterfacePermits bi-directionalcommunication to the TraneIntegrated Comfort system.LonTalk Communication InterfaceLCI-CProvides the LonMark chillerprofile input/outputs for use with ageneric BAS (Building AutomationSystem)Remote Input OptionsPermits remote chilled-liquid setpoint, remote current-limit set point,or both, by accepting a 4-20 mA or2-10 VDC analog signal.Remote Output OptionsPermits alarm relay outputs, icemaking outputs, or both.Protection GrillesProtection grilles cover the completecondensing coils and the serviceareas beneath the coils.Coil ProtectionA coated wire mesh that covers thecondenser coils only.RLC-PRC005-E4Condenser Corrosion ProtectionCopper fins and Black Epoxy Coatedaluminium fins are available on allsizes for corrosion protection. Jobsite conditions should be matchedwith the appropriate condenser finmaterials to inhibit coil corrosionand ensure extended equipment life.Service ValvesProvides a service valve on thesuction lines of each circuit tofacilitate compressor servicing.High-Ambient OptionThe high-ambient option consists ofspecial control logic to permit highambient (up to 52 C [125 F])operation. This option offers thebest performance when coupledwith the premium efficiency andperformance option.Low-Ambient OptionThe low-ambient option consists ofspecial control logic and fans topermit low-ambient (down to -18 C[0 F]) operation.Power Disconnect SwitchA disconnect switch with a throughthe-door handle, plus compressorprotection fuses, is provided todisconnect main power.Neoprene IsolatorsIsolators provide isolation betweenthe chiller and the structure to helpeliminate vibration transmission.Neoprene isolators are moreeffective and recommended overspring isolators.Flange adapter connection kitProvides a kit that includes a set oftwo pipe stubs and Grooved pipecouplings.Low Noise VersionThe unit is equipped with low-speedfans and a compressor soundattenuating enclosure. All thesound-emitting parts, like refrigerantlines are acoustically treated withsound-absorbent material.Night Noise SetbackAt night, on contact closure all thefans run at low speed, bringing theoverall sound level further down.Only available on Low Noise,non High Ambient units.Ground Fault DetectionSensing ground current forimproved chiller protection.Pressure GaugesA set of two pressure gauges perrefrigerant circuit, one for lowpressure and one for high pressure.Flow SwitchFor field installation on the chilledwater outlet connection.Under/Over-voltage protectionControls the variation of the powersupply voltage. If the value exceedsthe minimum or maximum voltage,the unit is shut down.IP20 protectionProvides a protection against directcontacts inside the control panel.The current-carrying parts areshrouded in order to preventaccidental contact.Evaporator connection(size 250-400)2 tubes are added at the inlet andthe outlet of the evaporator, so thatthe water Grooved pipe connectionis brought outside of the unit.Reduced length(sizes 400HE and 400XE)Total unit length is reduced whichallows transport in a 45' high cubecontainer. Performance is notaffected. Night noise setback andlow ambient options are notavailable.9

Application ConsiderationsFigure 4 - Flow rate Out of Range10 C5 L/s10 C7.6 L/sCV Pump5 L/sLoad10 C2.5 L/s13.7 C7.6 L/sCV pump7.6 L/sImportantCertain application constraintsshould be considered when sizing,selecting, and installing Trane aircooled Series R chillers. Unit andsystem reliability is often dependenton properly and completelycomplying with theseconsiderations. When theapplication varies from theguidelines presented, it should bereviewed with your local salesengineer.Unit SizingUnit capacities are listed in theperformance data section.Intentionally oversizing a unit toensure adequate capacity is notrecommended. Erratic systemoperation and excessive compressorcycling are often a direct result of anoversized chiller. In addition, anoversized unit is usually moreexpensive to purchase, install, andoperate. If oversizing is desired,consider using two units.1015.6 C5 L/sWater TreatmentDirt, scale, products of corrosion,and other foreign material willadversely affect heat transferbetween the water and systemcomponents. Foreign matter in thechilled-water system can alsoincrease pressure drop and,consequently, reduce water flow.Proper water treatment must bedetermined locally, depending onthe type of system and local watercharacteristics. Neither salt norbrackish water is recommended foruse in Trane air-cooled Series Rchillers. Use of either will lead to ashortened chiller life. Traneencourages the employment of areputable water-treatment specialist,familiar with local water conditions,to assist in this determination and inthe establishment of a proper watertreatment program.Effect of Altitude on CapacityAir-cooled Series R chiller capacitiesgiven in the performance data tablesare for use at sea level. At elevationssubstantially above sea level, thedecreased air density will reducecondenser capacity and, therefore,unit capacity and efficiency.Ambient LimitationsTrane air-cooled Series R chillers aredesigned for year-round operationover a range of ambienttemperatures. The air-cooled ModelRTAC chiller will operate in ambienttemperatures of 0 to 46 C [32 to115 F]. Selecting the high-ambientoption will allow the chiller tooperate in ambient temperatures of52 C [125 F], and selecting the lowambient option will increase theoperational capability of the waterchiller to ambient temperatures aslow as -18 C [0 F]. For operationoutside of these ranges, contact thelocal sales office.Water Flow LimitsThe minimum water flow rates aregiven in Tables P1-18. Evaporatorflow rates below the tabulatedvalues will result in laminar flowand cause freeze-up problems,scaling, stratification, and poorcontrol. The maximum evaporatorwater flow rate is also given in thegeneral data section. Flow ratesexceeding those listed may result inexcessive tube erosion.Flow Rates Out of RangeMany process cooling jobs requireflow rates that cannot be met withthe minimum and maximumpublished values within the ModelRTAC evaporator. A simple pipingchange can alleviate this problem.For example: a plastic injectionmolding process requires 5.0 L/s [80gpm] of 10 C [50 F] water andreturns that water at 15.6 C [60 F].The selected chiller can operate atthese temperatures, but has aminimum flow rate of 7.6 L/s [120gpm]. The following system cansatisfy the process.RLC-PRC005-E4

Application ConsiderationsFlow ControlTrane requires the chilled water flowcontrol in conjunction with the AirCooled Series R Chiller to be doneby the chiller.This will allow the chiller to protectitself in potentially harmfulconditions.Leaving-Water Temperature LimitsTrane air-cooled Series R chillershave three distinct leaving-watercategories: standard, lowtemperature, and ice making. Thestandard leaving-solutiontemperature range is 4.4 to 15.6 C[40 to 60 F]. Low-temperaturemachines produce leaving-liquidtemperatures less than 4.4 C [40 F].Since liquid supply temperature setpoints less than 4.4 C [40 F] resultin suction temperatures at or belowthe freezing point of water, a glycolsolution is required for all lowtemperature machines. Ice-makingmachines have a leaving-liquidtemperature range of -6.7 to 15.6 C[20 to 60 F]. Ice-making controlsinclude dual set point controls andsafeties for ice making and standardcooling capabilities. Consult yourlocal sales engineer for applicationsor selections involving lowtemperature or ice makingmachines. The maximum watertemperature that can be circulatedthrough an evaporator when theunit is not operating is 42 C [108 F].Leaving-Water TemperatureOut of RangeMany process cooling jobs requiretemperature ranges that cannot bemet with the minimum andmaximum published values for theRTAC evaporator. A simple pipingchange can alleviate this problem.For example: a laboratory loadrequires 7.6 L/s [120 gpm] of waterentering the process at 29.4 C [85 F]and returning at 35 C [95 F]. Theaccuracy required is higher than thecooling tower can give. The selectedchiller has adequate capacity, buthas a maximum leaving-chilledwater temperature of 15.5 C [60 F].In the example shown, both thechiller and process flow rates areequal. This is not necessary. Forexample, if the chiller had a higherflow rate, there would be morewater bypassing and mixing withwarm water.Supply-Water Temperature DropThe performance data for the Traneair-cooled Series R chiller is basedon a chilled-water temperature dropof 6 C [10.8 F]. Chilled-watertemperature drops from 3.3 to 10 C[6 to 18 F] may be used as long asminimum and maximum watertemperature, and minimum andmaximum flow rates, are notviolated. Temperature drops outsidethis range are beyond the optimumrange for control, and mayadversely affect themicrocomputer’s ability to maintainan acceptable supply-watertemperature range. Further,temperature drops of less than3.3 C [6 F] may result in inadequaterefrigerant superheat. Sufficientsuperheat is always a primaryconcern in any direct-expansionrefrigerant system and is especiallyimportant in a package chillerwhere the evaporator is closelycoupled to the compressor. Whentemperature drops are less than3.3 C [6 F], an evaporatorrunaround loop may be required.Figure 5 - Temperature Out of Range29.4 C7.6 L/s15.5 C2.2 L/s15.5 C7.6 L/sCV PumpLoad21 C7.6 L/sCV PumpRLC-PRC005-E435 C5.4 L/s15.5 C5.4 L/s35 C2.2 L/s35 C7.6 L/s11

Application ConsiderationsVariable Flow in the EvaporatorAn attractive chilled-water systemoption may be a variable primaryflow (VPF) system. VPF systemspresent building owners withseveral cost-saving benefits that aredirectly related to the pumps. Themost obvious cost savings resultfrom eliminating the secondarydistribution pump, which in turnavoids the expense incurred withthe associated piping connections(material, labor), electrical service,and variable-frequency drive.Building owners often cite pumprelated energy savings as the reasonthat prompted them to install a VPFsystem. With the help of a softwareanalysis tool such as Trace 700,Trace System Analyser , or DOE-2,you can determine whether theanticipated energy savings justifythe use of variable primary flow in aparticular application. It may also beeasier to apply variable primary flowin an existing chilled-water plant.Unlike the “decoupled” design, thebypass can be positioned at variouspoints in the chilled-water loop andan additional pump is unnecessary.The evaporator in the Model RTACcan withstand up to 50 percentwater flow reduction as long as thisflow is equal to or above theminimum flow-rate requirements.The microprocessor and capacitycontrol algorithms are designed tohandle a maximum of 10 percentchange in water flow rate perminute in order to maintain 0.28 C[ 0.5 F] leaving evaporatortemperature control. Forapplications in which system energysavings is most important and tighttemperature control is classified as /- 1.1 C [2 F ], up to 30 percentchanges in flow per minute arepossible.12Ice Storage ProvidesReduced Electrical DemandAn ice-storage system uses astandard chiller to make ice at night,when utilities charge less forelectricity. The ice supplements, oreven replaces, mechanical coolingduring the day, when utility ratesare at their highest. This reducedneed for cooling results in big utilitycost savings.Another advantage of ice storage isstandby cooling capacity. If thechiller is unable to operate, one ortwo days of ice may still beavailable to provide cooling. In thatperiod of time, the chiller can berepaired before building occupantsfeel any loss of comfort.The Trane Model RTAC chiller isuniquely suited to low-temperatureapplications like ice storage becauseof the ambient relief experienced atnight. This allows the Model RTACchiller to produce ice efficiently,with less stress on the machine.Simple and smart control strategiesare another advantage the ModelRTAC chiller offers for ice-storageapplications. Trane Tracer building management systems canactually anticipate how much iceneeds to be made at night, andoperate the system accordingly. Thecontrols are integrated right into thechiller. Two wires andpreprogrammed softwaredramatically reduce field installationcost and complex programming.RLC-PRC005-E4

Application ConsiderationsShort Water LoopsThe proper location of thetemperature control sensor is in thesupply (outlet) water connection orpipe. This location allows thebuilding to act as a buffer andassures a slowly-changing returnwater temperature. If there is not asufficient volume of water in thesystem to provide an adequatebuffer, temperature control can belost, resulting in erratic systemoperation and excessivecompressor cycling. A short waterloop has the same effect asattempting to control using thebuilding return water. Typically, atwo-minute water loop is sufficientto prevent a short water loop.Therefore, as a guideline, ensurethat the volume of water in theevaporator loop equals or exceedstwo times the evaporator flow rateper minute. For a rapidly changingload profile, the amount of volumeshould be increased. To prevent theeffect of a short water loop, thefollowing item should be givencareful consideration: a storage tankor larger header pipe to increase thevolume of water in the system and,therefore, reduce the rate of changeof the return water temperature.Applications Types Comfort cooling Industrial process cooling Ice or thermal storage Low-temperature process cooling.RLC-PRC005-E413

Application ConsiderationsTypical Unit InstallationOutdoor HVAC equipment must belocated to minimize noise andvibration transmission to theoccupied spaces of the buildingstructure it serves. If the equipmentmust be located in close proximityto a building, it could be placed nextto an unoccupied space such as astorage room, mechanical room,etc. It is not recommended to locatethe equipment near occupied, soundsensitive areas of the building ornear windows. Locating theequipment away from structureswill also prevent sound reflection,which can increase levels atproperty lines, or other sensitivepoints. When physically isolatingthe unit from structures, it is a goodidea to not use rigid supports, andto eliminate any metal-to-metal orhard material contact, whenpossible. This includes replacingspring or metal weave isolation withelastomeric isolators. Figure 6illustrates isolationrecommendations for the RTAC.Figure 6 - Unit isolation recommendations1 Wall sleeves (flexible connection)2 Piping hanger3 Rubber pads4 Flexible electrical conduit5 Concrete solid foundation6 Auxiliary interlocks connection14RLC-PRC005-E4

Selection ProcedureChiller selections and performanceinformation can be obtainedthrough the use of the Series R Chiller selection program.PerformanceThe computer selection programprovides performance data for eachchiller selection.Dimensional DrawingsThe dimensional drawings illustrateoverall measurements of the unit.Also shown are the serviceclearances required to easily servicethe RTAC chiller. All catalogdimensional drawings are subject tochange. Current submittal drawingsshould be referred to for detaileddimensional information. Contactthe sales office for submittalinformation.Electrical Data TablesCompressor motor electrical data isshown in the data section for eachcompressor size. Rated loadamperes (RLA), locked rotor StarDelta amperes (LRAY), the powerfactor for standard voltages for all50 Hz, 3-phase motors are shown.The RLA is based on theperformance of the motordeveloping full rated horsepower. Avoltage utilization range is tabulatedfor each voltage listed.Evaporator and Condenser PressureDropPressure drop data is determined bythe RTAC selection program.RLC-PRC005-E415

General DataSI UnitsTable G-1 - General Data RTAC 140-200 StandardSizeCooling capacity (5) (6)kWPower input (7)kWEnergy Efficiency Ratio (5) (6) (as Eurovent)kW/kWESEER (as Eurovent)kW/kWIPLV (According to ARI conditions 44 F leavingwater temperature, 95 C entering air temperature) kW/kWCompressorQuantityNominal Size (1)tonsEvaporatorEvaporator ModelWater StoragelMinimum Flowl/sMaximum Flowl/sNumber of water passesCondenserQuantity of CoilsCoil LengthmmCoil HeightmmFin seriesfins/ftNumber of RowsCondenser FansQuantity (1)DiametermmTotal Air Flowm3/sNominal RPMTip Speedm/sMotor kWkWMinimum Starting/Operating Ambient (2)Standard Unit CLow-Ambient Unit CGeneral UnitRefrigerantNumber of IndependentRefrigerant Circuits

In this mode, the chiller is the sole source of cooling. For example, to cool the building after all ice is produced but before high electric al-demand charges take effect, Tracer sets the air-cooled chiller leaving-fluid set point to its most efficient setting and starts the chiller, chiller pump, and load pump. When electrical demand is high, the