Air-Cooled Liquid Chillers

Trane 3-D Scroll CompressorSimple Design with 70% Fewer PartsFewer parts than an equal capacityreciprocating compressor meanssignificant reliability and efficiencybenefits. The single orbiting scrolleliminates the need for pistons,connecting rods, wrist pins and valves.Fewer parts lead to increased reliability.Fewer moving parts, less rotating massand less internal friction means greaterefficiency than reciprocatingcompressors.Features andBenefits(20–60 Ton)Proven Design Through Testing andResearchWith over twenty years of developmentand testing,Trane 3-D Scrollcompressors have undergone morethan 400,000 hours of laboratory testingand field operation.This work combinedwith over 25 patents makesTrane theworldwide leader in air conditioningscroll compressor technology.One of two matched scroll plates —the distinguishing feature of the scrollcompressor.Chart illustrates low torque variation of3-D Scroll compressor vs.reciprocating compressor.TheTrane 3-D Scroll provides importantreliability and efficiency benefits.The 3-DScroll allows the orbiting scrolls to touchin all three dimensions, forming acompletely enclosed compressionchamber which leads to increasedefficiency. In addition, the orbiting scrollsonly touch with enough force to create aseal; there is no wear between the scrollplates.The fixed and orbiting scrolls aremade of high strength cast iron whichresults in less thermal distortion, lessleakage, and higher efficiencies. Themost outstanding feature of the 3-DScroll compressor is that slugging willnot cause failure. In a reciprocatingcompressor, however, the liquid or dirtcan cause serious damage.Low Torque VariationThe 3-D Scroll compressor has a verysmooth compression cycle; torquevariations are only 30 percent of thatproduced by a reciprocating compressor.This means that the scroll compressorimposes very little stress on the motorresulting in greater reliability. Low torquevariation reduces noise and vibration.Suction Gas Cooled MotorCompressor motor efficiency andreliability is further optimized with thelatest scroll design. Cool suction gaskeeps the motor cooler for longer life andbetter efficiency.8CG-PRC007-EN

ApplicationConsiderationsCertain application constraints should beconsidered when sizing, selecting andinstallingTrane air-cooled chillers. Unitand system reliability is often dependentupon proper and complete compliancewith these considerations. Where theapplication varies from the guidelinespresented, it should be reviewed withyour localTrane sales engineer.Note: The terms water and solution areused interchangeably in the followingparagraphs.UNIT SIZINGUnit capacities are listed in the“Performance Data” section.Intentionally oversizing a unit to assureadequate capacity is not recommended.Erratic system operation and excessivecompressor cycling are often a directresult of an oversized chiller. In addition,an oversized unit is usually moreexpensive to purchase, install, andoperate. If oversizing is desired, considerusing two units.UNIT PLACEMENT1Setting The UnitA base or foundation is not required ifthe selected unit location is level andstrong enough to support the unit’soperating weight (see “Weights” sectionof this catalog).For a detailed discussion of base andfoundation construction, refer to theTrane Reciprocating RefrigerationManual. Manuals are available throughthe localTrane office.2Isolation and Sound EmissionThe most effective form of isolation is tolocate the unit away from any soundsensitive area. Structurally transmittedsound can be reduced by using springisolators. Spring isolators are generallyeffective in reducing vibratory noisegenerated by compressors, andtherefore, are recommended for soundsensitive installations. An acousticalengineer should always be consulted oncritical applications.CG-PRC007-ENFor maximum isolation effect, water linesand electrical conduit should also beisolated. Wall sleeves and rubber isolatedpiping hangers can be used to reduce thesound transmitted through water piping.To reduce the sound transmitted throughelectrical conduit, use flexible electricalconduit.State and local codes on soundemissions should always be considered.Since the environment in which a soundsource is located affects sound pressure,unit placement must be carefullyevaluated. Sound pressure and soundpower levels for chillers are available onrequest.3ServicingAdequate clearance for evaporator andcompressor servicing should beprovided. Recommended minimumspace envelopes for servicing are locatedin the dimensional data section and canserve as a guideline for providingadequate clearance.The minimum spaceenvelopes also allow for control paneldoor swing and routing maintenancerequirements. Local code requirementsmay take precedence.4Unit LocationaGeneralUnobstructed flow of condenser air isessential to maintain chiller capacity andoperating efficiency. When determiningunit placement, careful considerationmust be given to assure a sufficient flowof air across the condenser heat transfersurface.Two detrimental conditions arepossible and must be avoided: warm airrecirculation and coil starvation.Debris, trash, supplies, etc., should notbe allowed to accumulate in the vicinityof the air-cooled chiller. Supply airmovement may draw debris into thecondenser coil, blocking spaces betweencoil fins and causing coil starvation.Both warm air recirculation and coilstarvation cause reductions in unitefficiency and capacity because of thehigher head pressures associated withthem. In addition, in more severe cases,nuisance unit shutdowns will result fromexcessive head pressures. Estimates ofthe degree of efficiency and capacityreduction in such situations can bedetermined. Consult your localTranesales engineer.Cross winds, those perpendicular to thecondenser, tend to aid efficient operationin warmer ambient conditions, however,they tend to be detrimental to operationin lower ambients or when hot gasbypass is used due to the accompanyingloss of adequate head pressure. As aresult, it is advisable to protect air-cooledchillers from continuous direct windsexceeding 10 miles per hour in lowambient conditions.Low Ambient Operation — 20-60 Tonmodels — Human InterfaceRecommendationsWhen the temperature outside issubzero, who wants to be out theremonitoring or troubleshootingdiagnostics? Because we understand aservice technician’s reluctance to do this,we recommend using a Remote HumanInterface (RHI) panel. The servicetechnician can troubleshoot anddiagnose in the comfort of a mechanicalroom.Warm air recirculation occurs whendischarge air from the condenser fans isrecycled back to the condenser coil inlet.Coil starvation occurs when free airflowto the condenser is restricted.Condenser coils and fan discharge mustbe kept free of snow or otherobstructions to permit adequate airflowfor satisfactory unit operation.9

ApplicationConsiderationsbdWATER TREATMENTProvide Vertical ClearanceProvide Sufficient Unit-to-Unit ClearanceVertical condenser air discharge must beunobstructed. While it is difficult topredict the degree of warm airrecirculation, a unit installed as shownbelow would have its capacity andefficiency significantly reduced —possibly to the degree of nuisance highhead pressure trip outs. Performancedata is based on free air discharge.Units should be separated from eachother by sufficient distance to preventwarm air recirculation or coil starvation.Doubling the recommended single unitair-cooled chiller clearances willgenerally prove to be adequate.Dirt, scale, products of corrosion, andother foreign material in the water willadversely affect heat transfer betweenthe water and system components.Foreign matter in the chilled watersystem can also increase pressure dropand, consequently, reduce waterflow.Proper water treatment must bedetermined locally and depends on thetype of system and local watercharacteristics.eWalled Enclosure InstallationsWhen the unit is placed in an enclosureor small depression, the top of the fansshould be no lower than the top of theenclosure or depression. If they are,consideration should be given to ductingthe top of the unit. Ducting individualfans, however, is not recommended.Such applications should always bereviewed with the localTrane salesengineer.cProvide Lateral ClearanceThe condenser coil inlet must not beobstructed. A unit installed closer thanthe minimum recommended distance toa wall or other vertical riser mayexperience a combination of coilstarvation and warm air recirculation,resulting in unit capacity and efficiencyreductions and possible excessive headpressures.The recommended lateral clearances aredepicted in the dimensional data section.These are estimates and should bereviewed with the localTrane salesengineer at the jobsite.10Do not use salt or brackish water inTranechillers. Use of either will lead to ashortened life.Trane encourages theemployment of a reputable watertreatment specialist, familiar with localwater conditions, to assist in theestablishment of a proper watertreatment program.The capacities given in the “PerformanceData” section of this catalog are basedon water with a fouling factor of 0.0001(in accordance with ARI 550/590-98). Forcapacities at other fouling factors, see“Performance Adjustment Factors”section of this catalog.EFFECT OF ALTITUDE ONCAPACITYVOLTAGENominal voltage is the nameplate ratingvoltage.The actual range of line voltagesat which the equipment can satisfactorilyoperate are given -440374-456414-508520-635Chiller capacities given in the“Performance Data” section are basedupon application at sea level. Atelevations substantially above sea level,the decreased air density will decreasecondenser capacity and, therefore, unitcapacity and efficiency. The adjustmentfactors in the “Performance AdjustmentFactors” section of this catalog can beapplied directly to the performance datato determine the unit’s adjustedperformance.CG-PRC007-EN

ApplicationConsiderationsAMBIENT

Air-Cooled Liquid Chillers 10, 15 Tons 20–60 Tons Design and manufacturing excellence makes Trane a leader in the air-cooled chiller marketplace. For over 40 years, Trane has been using the best engineering available in development, manufacturing, and marketing to produce quality products. This tradition of using excellence to meet market