Helical Rotary Water Chillers

A Trane Air Conditioning Clinic

Helical-Rotary Water Chillers

Air Conditioning Clinic TRG-TRC012-ENAir Conditioning Clinic TRG-TRC012-EN© American Standard Inc. 1999


ChilledWaterSystem


absorption centrifugal

helical-rotary


air-cooled

water-cooled




period one

Components


liquid/vapor liquid/vapor separatorseparator

motormotor

oil separatoroil separator

condensercondenser

oil supply oil supply systemsystem

compressorcompressor

controlcontrolpanelpanel

evaporatorevaporator

components of a

Helical-Rotary Water Chiller

starterstarter


compressor...

Helical Rotors


compressor...

Helical Rotors

male rotormale rotor

female rotorfemale rotor

housinghousing

slide valveslide valve


compressor...

Helical Rotors

intakeintakeportport


compressor...

Helical Rotors

intakeintakeportport

pocket of refrigerant vaporpocket of refrigerant vapor


compressor...

Helical Rotors

discharge portdischarge port

intake portintake port


compressor...

Helical Rotors

meshing pointmeshing point

discharge portdischarge port


Oil Separator

refrigerant vaporrefrigerant vaporand oil mixtureand oil mixture

oil return to sumpoil return to sump

refrigerant vapor refrigerant vapor to condenserto condenser


Oil Supply System

master master solenoid solenoid valvevalve

oil tank oil tank sumpsump

oil filteroil filter

oil oil separatorseparator

rotor bearingsrotor bearings

rotorrotorrefrigerant refrigerant vapor to vapor to condensercondenser


1122


water-cooled

Condenser

subcoolersubcooler

liquid liquid refrigerantrefrigerant

bafflebaffle

tube bundletube bundle

refrigerant vaporrefrigerant vapor

cooling cooling tower tower waterwater


air-cooled

Condenser

subcoolersubcooler

outdoor airoutdoor air

condenser condenser coilcoil

propeller fanpropeller fan


expansion device…

Electronic Expansion Valve


expansion device…

Orifice Plates

totoevaporatorevaporatororifice platesorifice plates

HH


Liquid/Vapor Separator

from from expansion expansion devicedevice

liquid refrigerant liquid refrigerant to evaporatorto evaporator

refrigerant vapor refrigerant vapor to compressorto compressor


chilled chilled water water returnreturn

liquid level liquid level sensorsensor


refrigerant vaporrefrigerant vapor

Flooded Evaporator

liquidliquidrefrigerantrefrigerant

chilled chilled water water supplysupply


Direct Expansion Evaporator

refrigerant refrigerant vapor vapor

liquid liquid refrigerantrefrigerant

chilled chilled water water returnreturn

chilled chilled water water supplysupply


bafflesbaffles


Controls and Starter


starterstarter



period two

Refrigeration Cycle


helical-rotary water chiller

Refrigeration Cycle


condensercondenser


expansion expansion devicedevice

liquid/vaporliquid/vaporseparatorseparator



Pressure–Enthalpy (p-h) Chart

enthalpyenthalpy

subcooledsubcooledliquidliquid

mixture of mixture of liquid and liquid and vaporvapor

pres

sure

pres

sure

superheatedsuperheatedvaporvapor

BA

46.4 Btu/lb46.4 Btu/lb[256.4 kJ/kg][256.4 kJ/kg]

147.5 psia147.5 psia[1.02 MPa][1.02 MPa]

116.6 Btu/lb116.6 Btu/lb[419.6 kJ/kg][419.6 kJ/kg]


helical-rotary water chiller

Refrigeration Cycle

66

pres

sure

pres

sure

enthalpyenthalpy

evaporatorevaporator11

2255

77

condensercondenser

compressorcompressorexpansionexpansiondevicedevice liquid/vapor liquid/vapor

separatorseparator

44 33


helical-rotary water chillers…

Refrigerants

HCFC-22 HFC-134a HFC-404a HFC-407c HFC-410a


002020404060608080

100100120120140140160160

HCFC-22HCFC-22 HFC-134aHFC-134a HFC-404aHFC-404a HFC-407cHFC-407c HFC-410aHFC-410a

efficiencyefficiency capacitycapacity pressurepressure

refrigerants…

Thermodynamic Characteristics

perc

ent

perc

ent



period three

Compressor Capacity Control


Slide Valve

axial axial discharge discharge portport


radial radial discharge discharge portport


slide valve position...

Full Load

radial portradial portradial portradial port

axial portaxial portaxial portaxial portslide valve(closed)

compressor compressor dischargedischarge


slide valve position...

Part Load

valvevalveopeningopening

to suctionto suction

radial portradial port

axial portaxial portslide valve


open


compressor capacity control...

Unloading

slide valve

openradial portradial port


to suctionto suction

valvevalveopeningopening


Slide Valve Operation

to low-to low-pressure pressure compressor compressor housinghousing

high-pressure high-pressure refrigerant vaporrefrigerant vapor

slide valve slide valve operator operator shaftshaft

springspring pistonpiston cylindercylinder

loadloadvalvevalve

unloadunloadvalvevalve



period four

Maintenance Considerations


helical-rotary water chillers

Maintenance Considerations

Operating log Mechanical

components Heat transfer

surfaces Fluid analysis

operating log

ASHRAE Guideline 3


Chilled water inlet and outlet temperatures and pressures

Chilled water flow Evaporator refrigerant

temperature and pressures Evaporator approach

temperature Condenser water inlet and

outlet temperatures and pressures

Condenser water flow Condenser refrigerant

temperature and pressures Condenser approach

temperature

Compressor refrigerant suction and discharge temperatures

Refrigerant level

Oil pressures, temperature, and levels

Addition of refrigerant

Addition of oil

Vibration levels


Required maintenance Compressor and motor: no maintenance required Controls: no maintenance or calibration required

Recommended maintenance Visually inspect overall unit Inspect safety controls and electrical components Tighten electrical connections Check for leaks Test vent piping

maintenance considerations

Mechanical Components


Other design-specific requirements: Change oil when oil analysis dictates Replace oil filter periodically Replace filter drier periodically Clean oil strainers annually Check shaft alignment annually Check coupling annually Replace shaft seal every 2 to 4 years Compressor teardown inspection every 5 to 10 years


Mechanical Components



Heat Transfer Surfaces

Recommended maintenance Use a qualified water treatment

specialist Clean condenser tubes as

needed (water-cooled) Clean water-side strainers Test tubes every 3 years Clean condenser coils as

needed (air-cooled)



Fluid Analysis

Oil analysis Conduct annual analysis to verify

system integrity Measure oil pressure drop to

determine if filter needs changing Measure charge

Refrigerant charge Measure charge and trim as

necessary Measure superheat and subcooling



Fluid Analysis

Why perform regular oil analyses? Helps reduce maintenance costs Detects problems without compressor

disassembly Extends service life of oil charge Reduces environmental problems

related to oil disposal Helps maintain compressor

efficiency and reliability Helps lower refrigerant emissions



period five

Application Considerations


condenser types…

Air-Cooled or Water-Cooled


water-cooled Greater energy efficiency Longer equipment life

air-cooled or water-cooled

Comparison

air-cooled Lower maintenance Packaged system Better low ambient

operation


cooling towercooling tower

condensercondenserwater water pumppump

condensercondenser

Condensing Temperature Control


condensercondenser

bypassbypass

cooling towercooling tower

condensing temperature control

Cooling Tower Bypass

55°F55°F[13°C][13°C]

40°F40°F[4°C][4°C]

65°F65°F[18°C][18°C]

divertingdivertingvalvevalve


evaporator water flow…

Constant or Variable Flow

variable variable speed speed drivedrive

chilledchilledwater water pumppump



variable evaporator water flow

Limitations

Maintain minimum and maximum water flow rates through the chiller evaporator

Rate at which evaporator water flow changes must be kept below the corresponding limit to: Maintain the chilled water set point control Keep the chiller on line Protect the chiller from damage


loadload



Short Evaporator Water Loops


loadload



Short Evaporator Water Loops

tanktank


equipment certification standards

ARI Standard 550/590

Purpose Establish definitions and

testing and rating requirements

Scope Factory designed and

prefabricated water chillers Vapor-compression

refrigeration Air-cooled and water-cooled

condensing


equipment certification standards

ARI Standard 550/590

Standard rating conditions Common system conditions for published ratings

Integrated Part Load Value (IPLV) Part-load efficiency rating Based on an “average” single-chiller installation Standard operating conditions



period six

Review


Review—Period 1

liquid/vapor liquid/vapor separatorseparator

motormotor


condensercondenser

oil supply oil supply systemsystem



evaporatorevaporatorstarterstarter


Review—Period 2

66

pres

sure

pres

sure

enthalpyenthalpy

evaporatorevaporator11

2255

77

condensercondenser

compressorcompressorexpansionexpansiondevicedevice liquid/vapor liquid/vapor

separatorseparator

44 33


Review—Period 3

axial axial discharge discharge portport


radial radial discharge discharge portport


Review—Period 4

Maintenance considerations Operating log Mechanical components Heat transfer surfaces Fluid analysis


Review—Period 5

Application considerations Air-cooled or water-cooled Condensing temperature control Constant or variable evaporator water flow Short evaporator water loops Equipment certification standards

Helical Rotary Water Chillers

Documents

Transcript of Helical Rotary Water Chillers