A Trane Air Conditioning Clinic Centrifugal Water Chillers Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc. 1999

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Chilled Water System

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc absorption centrifugal helical-rotary

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Centrifugal Water Chillers

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Centrifugal Water Chillers period one Components

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc condenser compressor control panel evaporator components of a Centrifugal Water Chiller starter motor

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Compressor

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Impeller blades

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc volute diffuser passage impeller passages Centrifugal Compressor

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc centrifugal compressor Energy Conversion refrigerant enters diffuser path through compressor velocity static pressure refrigerant enters impeller refrigerant enters volute

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Multistage Compressor

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Condenser baffle tubebundle liquid refrigerant refrigerant vapor cooling tower water

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc toevaporator orifice plates H1H1H1H1 expansion device Orifice Plates

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc expansion device Orifice Plates H2H2H2H2 toevaporator orifice plates

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc stage chiller Economizer refrigerant vapor to second stage of compression liquid refrigerant to evaporator orifice liquid refrigerant from condenser

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc stage chiller Economizer liquid refrigerant to evaporator orifice orifice refrigerant vapor to second stage of compression refrigerant vapor to third stage of compression liquid refrigerant from condenser

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Evaporator eliminator liquiddistributor orifice system liquid refrigerant tube bundle chilled water return

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Motor impellers impeller motor motor gear-drive direct-drive gears

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Hermetic Motor Cooling stator rotor drain liquidrefrigerant

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Controls and Starter control panel starter

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Starters remote-mounted starter line power control power wiring unit-mounted line power control power wiring

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Centrifugal Water Chillers period two Refrigeration Cycle

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc stage centrifugal chiller Refrigeration Cycle condenser evaporator expansion devices economizer 2-stagecompressor

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Pressure-Enthalpy (p-h) Chart enthalpy subcooledliquid mixture of liquid and vapor 15.5 Btu/lb [201.0 kJ/kg] pressure superheatedvapor B A 5 psia [0.034 MPa] 92.4 Btu/lb [380.4 kJ/kg]

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc stage centrifugal chiller Refrigeration Cycle pressure enthalpy evaporator condenser 2-stage compressor expansion devices 8 9 PePePePe PcPcPcPc P1P1P1P15economizer

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc stage centrifugal chiller Refrigeration Cycle1 2pressure enthalpy evaporator condenser PePePePe PcPcPcPc P1P1P1P1 CB A stage compressor economizer3 4 expansion devices 10 8

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc pressure temperature HCFC-22 HCFC-123 atmosphericpressure Refrigerant Operating Pressures HFC-134a

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Low-Pressure Chillers compressor suction elbow evaporator

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Purge System

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Purge Operation filtration canister refrigerant vapor from condenser to condenser filter drier purge evaporator coil purge tank to chiller vent line

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Centrifugal Water Chillers period three Compressor Capacity Control

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Inlet Vanes inlet vanes impeller

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Multistage Compressor inlet vanes impellers

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc VrVrVrVr R VtVtVtVt Impeller

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Impeller Dynamics diameter V r refrigerant flow rate V r  refrigerant flow rate V t rotational speed × diameter V t  rotational speed × diameter rotational speed VrVrVrVr R VtVtVtVt refrigerant flow rate

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Compressor Unloading VrVrVrVr R VtVtVtVt VrVrVrVr VtVtVtVt full load part load R

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc VrVrVrVr VtVtVtVt Surge V r < static pressure R

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Compressor Map pressure difference refrigerant flow rate surge vane position (degrees)

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Operating Point pressure difference refrigerant flow rate operatingpoint

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc compressor map for a 2-Stage Compressor pressure difference refrigerant flow rate surge operatingpoint vane position (degrees)

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc compressor map for a 2-Stage Compressor pressure difference refrigerant flow rate surge C B A unloading line

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Adjustable-Frequency Drives power consumption load inlet vanes only AFD + inlet vanes

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Centrifugal Water Chillers period four Maintenance Considerations

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Maintenance Considerations s Operating log s Mechanical components s Heat-transfer surfaces s Fluid analysis

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc operating log ASHRAE Guideline 3 s Chilled water inlet and outlet temperatures and pressures s Chilled water flow s Evaporator refrigerant temperature and pressures s Evaporator approach temperature s Condenser water inlet and outlet temperatures and pressures s Condenser water flow s Condenser refrigerant temperature and pressures s Condenser approach temperature s Oil pressures, temperature, and levels s Addition of refrigerant s Addition of oil s Vibration levels

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc maintenance considerations Mechanical Components s Required maintenance u Compressor and motor: no maintenance required u Controls: no maintenance or calibration required s Recommended maintenance u Visually inspect overall unit u Inspect safety controls and electrical components u Tighten electrical connections u Check for leaks

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc s Other design-specific requirements u Change oil when oil analysis dictates u Replace oil filter periodically u Replace filter drier periodically u Clean oil strainers annually u Check shaft alignment annually u Check coupling annually u Replace shaft seal every 2 to 4 years u Compressor teardown inspection every 5 to 10 years maintenance considerations Mechanical Components

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc maintenance considerations Heat Transfer Surfaces s Recommended maintenance u Use a qualified water treatment specialist u Clean condenser tubes as needed u Clean water-side strainers u Test tubes every 3 years

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Fluid Analysis s Oil analysis u Conduct annual analysis to verify system integrity u Measure oil pressure drop to determine if filter needs changing u Measure charge s Refrigerant charge u Conduct analysis of refrigerant u Inspect purge system

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Oil Analysis s Why perform regular oil analysis? u Helps reduce maintenance costs u Detects problems without compressor disassembly u Extends service life of oil charge u Reduces environmental problems related to oil disposal u Helps maintain compressor efficiency and reliability u Helps lower refrigerant emissions

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Centrifugal Water Chillers period five Application Considerations

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Condensing Temperature Control pressure difference refrigerant flow rate surge B A C vane position (degrees) unloading line

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc condensing temperature control Cooling Tower Bypass condenser bypass cooling tower 55°F[13°C] 40°F [4°C] 65°F [18°C] divertingvalve

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc evaporator water flow Constant or Variable Flow variable- speed drive chilled water pump evaporator

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc variable evaporator water flow Limitations s Maintain minimum and maximum water flow rates through the chiller evaporator s Rate at which the evaporator water flow changes must be kept below the corresponding limit to: u Maintain the chilled water set point control u Keep the chiller on line u Protect the chiller from damage

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Short Evaporator-Water Loops load chilled water pump evaporator

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Short Evaporator-Water Loops load chilled water pump evaporator tank

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Heat Recovery heat-recovery condenser cooling tower water standard condenser

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc heat-recovery (dual) condenser auxiliary condenser u No extra condenser u Large base heating loads or continuous operation u High hot water temperatures u Controlled u Chiller efficiency preserved u Second, full- size condenser u Large heating loads u High hot water temperatures u Controlled u Degrades chiller efficiency u Second, smaller size condenser u Preheating loads u Moderate hot water temperatures u Uncontrolled u Improves chiller efficiency heat pump Heat-Recovery Chiller Options

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc air-side economizer strainer cycle u Potential fouling limited to heat exchanger u Requires additional heat exchanger, piping, valves, and controls u Can operate simultaneously with chiller u Most efficient u Requires larger outdoor air, return, and exhaust duct systems u Coldest water temperatures u Potential fouling in chilled water loop u Requires additional piping, valves, and controls plate-and-frame heat exchanger Free Cooling

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc free cooling Refrigerant Migration from compressor to compressor evaporator condenser

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc equipment certification standards ARI Standard 550/590 s Purpose u Establish definitions, testing, and rating requirements s Scope u Factory designed and prefabricated water chillers u Vapor-compression refrigeration u Air-cooled and water-cooled condensing

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc equipment certification standards ARI Standard 550/590 s Standard rating conditions u Common system conditions for published ratings u Fouling factor s Integrated Part Load Value (IPLV) u Part-load efficiency rating u Based on an “average” single-chiller installation u Standard operating conditions

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Centrifugal Water Chillers period six Review

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Review—Period 1 condenser compressor control panel evaporator starter motor

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Review—Period pressure enthalpy evaporator condenser 2-stage compressor expansion devices 8 9 PePePePe PcPcPcPc P1P1P1P15economizer

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Review—Period 3 inlet vanes impellers

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Review—Period 4 s Maintenance considerations u Operating log u Mechanical components u Heat-transfer surfaces u Fluid analysis

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc Review—Period 5 s Application considerations u Condensing temperature control u Constant or variable evaporator-water flow u Short evaporator-water loops u Heat recovery u Free cooling u Equipment certification standards

Air Conditioning Clinic TRG-TRC010-EN © American Standard Inc. 1999