Trane TRG-TRC010-EN Bedienungsanleitung

Air ConditioningClinicCentrifugalWater ChillersOne of the Equipment SeriesTRG-TRC010-EN85577_Cover.fm Page 1 Wednesday, September 1, 1999 10:08 AM

TRG-TRC010-EN 3notesperiod oneComponentsMany of the components of the centrifugal water chiller are similar to those of other chiller types.This parti

4 TRG-TRC010-ENnotesperiod oneComponentsCompressorThe centrifugal compressor uses the principle of dynamic compression, which involves converting ener

TRG-TRC010-EN 5period oneComponentsnotesThe rotation of the impeller causes the refrigerant vapor to accelerate within the impeller passages, increasi

6 TRG-TRC010-ENnotesperiod oneComponentsAgain, in the passages of the rotating impeller, the refrigerant vapor accelerates, increasing its velocity an

TRG-TRC010-EN 7period oneComponentsnotesthe accelerated refrigerant vapor leaves the last impeller, it collects in the compressor volute and travels o

8 TRG-TRC010-ENnotesperiod oneComponentsExpansion DeviceAn expansion device is used to maintain the pressure difference between the high-pressure (con

TRG-TRC010-EN 9period oneComponentsnotesAs the load decreases, less refrigerant moves through the chiller and the level of the liquid column drops. No

10 TRG-TRC010-ENnotesperiod oneComponentsLiquid refrigerant from the condenser enters the first expansion device, which reduces the pressure of the re

TRG-TRC010-EN 11period oneComponentsnotesAgain, the final expansion device reduces the pressure and temperature of the refrigerant to evaporator condi

12 TRG-TRC010-ENnotesperiod oneComponentsMotorA motor is used to rotate the impeller(s). A direct-drive motor is connected directly to the impeller sh

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TRG-TRC010-EN 13period oneComponentsnoteschiller’s refrigeration system—and uses a coupling to connect the motor and compressor shafts.The heat genera

14 TRG-TRC010-ENnotesperiod oneComponentsperformance is a system-wide issue, not just a matter of chiller design and control.A starter links the chill

TRG-TRC010-EN 15notesA pressure–enthalpy (p-h) chart illustrates the refrigeration cycle of the centrifugal water chiller.First, let’s review the comp

16 TRG-TRC010-ENnotesperiod twoRefrigeration CycleThe pressure drop created by the second expansion device lowers the pressure and temperature of the

TRG-TRC010-EN 17period twoRefrigeration CyclenotesRefrigerant leaves the evaporator as saturated vapor ➀ and flows to the first-stage impeller of the

18 TRG-TRC010-ENnotesperiod twoRefrigeration CycleThe change in enthalpy from C to A that occurs during the refrigeration cycle is called the refriger

TRG-TRC010-EN 19period twoRefrigeration CyclenotesRefrigerantsWhen selecting which refrigerant to use in a centrifugal water chiller, the manufacturer

20 TRG-TRC010-ENnotesperiod twoRefrigeration Cycle

TRG-TRC010-EN 23period threeCompressor Capacity ControlnotesIn a multistage centrifugal compressor, the operating characteristics of each impeller are

24 TRG-TRC010-ENnotesperiod threeCompressor Capacity Controlrefrigerant. Recall that kinetic energy is converted to static energy, or static pressure.

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TRG-TRC010-EN 25period threeCompressor Capacity ControlnotesConsider a given-diameter compressor impeller that rotates at a constant speed. As the loa

26 TRG-TRC010-ENnotesperiod threeCompressor Capacity ControlAs the load and the corresponding refrigerant flow rate continue to fall, the radial veloc

TRG-TRC010-EN 27period threeCompressor Capacity Controlnotesconditions that cause the compressor to surge. Any operating point that falls to the right

28 TRG-TRC010-ENnotesperiod threeCompressor Capacity ControlThe starting point (A) is the full-load operating point. As the load on the chiller decrea

TRG-TRC010-EN 29period threeCompressor Capacity ControlnotesAn adjustable-frequency drive (AFD), or variable-speed drive, is another device used to va

30 TRG-TRC010-ENnotesperiod fourMaintenance ConsiderationsThis period discusses general maintenance requirements of centrifugal water chillers. Althou

TRG-TRC010-EN 31period fourMaintenance ConsiderationsnotesGuideline 3, “Reducing Emission of Halogenated Refrigerants in Refrigeration and Air Conditi

32 TRG-TRC010-ENnotesperiod fourMaintenance ConsiderationsThe compressor/motor assembly in direct-drive, hermetic compressor designs requires little p

TRG-TRC010-EN 33period fourMaintenance ConsiderationsnotesSome centrifugal compressor designs do require periodic maintenance of mechanical system com

34 TRG-TRC010-ENnotesperiod fourMaintenance ConsiderationsScale deposits are best removed by chemical means. During this process, the water-cooled con

CentrifugalWater ChillersOne of the Equipment SeriesA publication ofThe Trane Company—Worldwide Applied Systems Grouptrgtrc010_book.book Page i Wedn

TRG-TRC010-EN 35period fourMaintenance ConsiderationsnotesRegularly logging oil and refrigerant charges, and examining the trends of this data, can he

36 TRG-TRC010-ENnotesperiod fiveApplication ConsiderationsSeveral considerations must be addressed when applying centrifugal water chillers, including

TRG-TRC010-EN 37period fiveApplication ConsiderationsnotesCondensing Temperature ControlTo achieve stable compressor unloading over a wide range of co

38 TRG-TRC010-ENnotesperiod fiveApplication ConsiderationsControlling the refrigerant pressure difference between the evaporator and condenser of a wa

TRG-TRC010-EN 39period fiveApplication ConsiderationsnotesConstant or Variable Evaporator Water FlowPrevious chiller designs required that a constant

40 TRG-TRC010-ENnotesperiod fiveApplication Considerations1) The water flow rate through the chiller evaporator must stay between the minimum and maxi

TRG-TRC010-EN 41period fiveApplication ConsiderationsnotesShort water loops may be unavoidable in close-coupled or very small applications, particular

42 TRG-TRC010-ENnotesperiod fiveApplication ConsiderationsHeat RecoverySalvaging usable heat from the refrigeration cycle—heat that would normally be

TRG-TRC010-EN 43period fiveApplication ConsiderationsnotesThree types of heat-recovery chillers are commonly available:The dual-condenser, or double-b

44 TRG-TRC010-ENnotesperiod fiveApplication ConsiderationsFree CoolingMany buildings require some form of year-round cooling to handle interior spaces

Preface© 1999 American Standard Inc. All rights reservedTRG-TRC010-ENiiThe Trane Company believes that it is incumbent on manufacturers to serve the i

TRG-TRC010-EN 45period fiveApplication ConsiderationsnotesThis leads to the discussion of a free cooling principle called refrigerant migration. It in

46 TRG-TRC010-ENnotesperiod fiveApplication ConsiderationsEquipment Certification StandardsThe Air Conditioning & Refrigeration Institute (ARI) es

TRG-TRC010-EN 47period fiveApplication Considerationsnotesgiven system—they simply define a common rating point to aid comparisons. Trends toward impr

48 TRG-TRC010-ENnotesLet’s review the main concepts that were covered in this clinic on centrifugal water chillers.Period 1 introduced the following c

TRG-TRC010-EN 49period sixReviewnotesPeriod 2 described the refrigeration cycle of 2-stage centrifugal water chillers with a pressure-enthalpy chart.

50 TRG-TRC010-ENnotesperiod sixReviewPeriod 4 described the general maintenance requirements of a centrifugal water chiller, including: Recommended

TRG-TRC010-EN 51period sixReviewnotesFor more information, refer to the following references: Trane product catalogs for centrifugal water chiller pr

52 TRG-TRC010-ENQuestions for Period 11) A centrifugal compressor converts ___________ energy to ____________ energy.2) Does the refrigerant velocity

TRG-TRC010-EN 53Quiz8) What velocity component is directly proportional to the impeller’s rotational speed times its diameter?9) What are the 2 most c

54 TRG-TRC010-EN1) kinetic energy to static energy2) impeller3) By flashing a portion of the refrigerant prior to entering the evaporator, the economi

TRG-TRC010-EN iiiContentsIntroduction ... 1period one Components ...

TRG-TRC010-EN 55adjustable-frequency drive (AFD) A device used to vary the capacity of a centrifugal compressor by varying the speed of the motor that

56 TRG-TRC010-ENGlossaryeconomizer The component of a multistage centrifugal chiller used to remove vapor from the refrigerant mixture after it passes

TRG-TRC010-EN 57Glossarynotespressure-enthalpy chart A graphical representation of the saturated properties of a refrigerant, plotting refrigerant pre

The Trane CompanyWorldwide Applied Systems Group3600 Pammel Creek RoadLa Crosse, WI 54601-7599www.trane.comAn American Standard CompanyLiterature Ord

iv TRG-TRC010-ENtrgtrc010_book.book Page iv Wednesday, September 1, 1999 10:39 AM

TRG-TRC010-EN 1notesIntroductionWater chillers are used in a variety of air conditioning and process cooling applications. They are used to make cold

2 TRG-TRC010-ENnotesIntroductionWater chillers using the vapor-compression refrigeration cycle vary by the type of compressor used. Reciprocating and