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WATER-COOLEDCHILLERS WITH ROTARYSCREW COMPRESSORS
50/60 Hz
Products That Perform . . .By People Who Care
®
Form No: MS0420B
INTRODUCTIONINTRODUCTION
Dunham-Bush's WCOX water cooled water chiller is the newest addition to a large family of rotaryscrew chillers, and follows on the heels of thirty-five years of experience and dedicated rotary screwtechnology and advancements. Dunham-Bush, the world's largest manufacturer of screw compressorizedair conditioning, has over 20,000 screw compressor installations working worldwide -representing overone-half of all the screw compressors in the world today.
All units are factory run tested before shipment.
TABLETABLE OF CONTENTSCONTENTS
Introduction ..................................................................................................................................... 2Nomenclature ................................................................................................................................... 2Components...................................................................................................................................... 3Standard Features ............................................................................................................................. 4Unit Features, Compressor................................................................................................................. 5Unit Features, Microcomputer Control................................................................................................ 8Unit Features, Part Load Performance ...............................................................................................10Typical Sequence of Operation..........................................................................................................11Dimensional Data ............................................................................................................................12Physical Data...................................................................................................................................14Pressure Drop ..................................................................................................................................16Electrical Data .................................................................................................................................17Typical Wiring Diagram...................................................................................................................18Application Data, Heat Recovery......................................................................................................19Application Data, Point- Loadings .....................................................................................................20Standard Equipment and Factory Installed Options .............................................................................21Guide Specifications.........................................................................................................................22
NOMENCLATURE
WCOX 089 AR P5 K5 B
Open Drive Rotary ScrewPackaged Water CooledWater Chiller
Compressor Designation056, 066, 080, 089, 107
Generation Designation
Condenser Designation
Evaporator Designation
Electrical CodeAS -575/3/60 AU -400/3/50AX -2300/3/60 AR -460/3/60AY- 4160/3/60
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COMPONENTS
Computer PerformanceRatings
Dunham-Bush WCOX Water-Cooled RotaryScrew Water Chillers are available from 431 to992 tons. The vast number of combinations ofheat exchangers, compressors and motors make itimpractical to publish tabular ratings for eachcombination. A chiller may be custom matched tocertain building requirements by your Dunham-Bush Sales Representative utilizing the WCOXComputer Selection Program which has ratingsare according to ARI Standard 550/590-98. Datawhich can be provided to you will include:
] Chiller Capacity
] KW Input
] Evaporator and Condenser Water PressureDrop
] Evaporator and Condenser Tube WaterVelocities
] IPLV / APLV
] Part-Load Performance
Contact your local Dunham-Bush SalesReprsentative to discuss what Real SolutionsDunham-Bush can offer to solve your chillerselection questions.
Unit Control box Microcomputer forprecise and reliable
control
Compact, quietLSC compressor
Evaporator ASME codedrefrigerant side
vessels
Cleanable andremovable enhanced
copper tube heatexchangers
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STANDARD FEATURES
Compressor Experience] Thirty-five years of rotary screw experience and dedicated technological advancements] Simply designed for high reliability with only two rotating parts] Insured continuous oil flow to compressor through separate oil pump and high efficiency external oil
separator] Many of these compressors have operated over 100,000 hours and never been opened, let alone
overhauled
Energy Efficiency] Designed to provide the greatest amount of cooling for the least kilowatt input over the entire operating
range of your building] Delivers outstanding efficiency and total energy savings through the use of microcomputer controlled
slide valve and evaporator leaving water control] High efficiency external oil separator guarantees removal of oil carried over in the refrigerant and
maintains the heat exchangers at their maximum efficiency at both full and part load] Rating according to ARI Standard 550/590-98 "Centrifugal or Rotary Screw Liquid Chilling Packages"] Meets or exceeds ASHRAE Standard 90.1 Energy Efficiency Code
Installation Ease] The WCOX has a smaller footprint than comparable centrifugal chillers and takes up less equipment
room space] Small size, especially low height, makes the WCOX ideal for retrofit when it comes time to change out
obsolete CFC chillers or absorption units
Safety Code Compliance] Vessel design approved and certified by JKKP] ASME Boiler and Pressure Vessel Code, Section VIII Division 1 "Unfired Pressure Vessels"] ASME Standard B31.5 Refrigerant Piping] ASHRAE Standard 15 Safety Code for Mechanical Refrigeration
Refrigerant Compatibility] Designed to operate with environmentally safe and economically smart HCFC-22 with proven
efficiency and reliability] Consult factory for use with new HFC refrigerants
Control Flexibility] Microcomputer-based with DDC (direct digital control) features precise push button control over every
aspect of operation with built-in standard features that allow extra energy savings on startup andthroughout the life of the equipment
] Insured optimum energy efficiency through microcomputer controls which utilize pressure transducersto measure evaporator and condenser pressure
] Lower energy costs resulting from automatic load monitoring] Monitor your chiller's key functions from a remote location with a simple, low cost, phone modem
option] Proactive control by microcomputer that anticipates problems and takes corrective action before they
occur. Controls will unload compressor if head and suction pressure approach limits. This will allowunit to stay on the line while warning operator of potential problems
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UNIT FEATURES COMPRESSOR
DIRECT DRIVE COMPRESSOR FEATURES
Compressor Assembly - The Dunham-Bushrotary Compressor is a positive displacement helical-axial design to use with high pressure refrigerants.] The compressor consists of two intermeshing
helical grooved rotors in a stationary housing withsuction and discharge gas ports.
] Uniform gas flow, even torque and positivedisplacement, all provided by pure rotary motion,contribute to vibration free operation over a widerange of operating conditions. Intake anddischarge cycles overlap effectively, producing asmooth, continuous flow of gas.
Simplified Capacity Control -The slide valvemechanism for capacity modulation and part loadoperation is an outstanding feature.] Moving parts are simple, rugged and trouble free.
The slide mechanism is hydrostatically supportedwith aid from a pressurized oil supply.
] Package capacity reduction can be down to as lowas 10% without HGBP by progressive movementof the slide valve away from the valve stop.
] Capacity reduction is programmed by an exclusiveelectronically initiated, hydraulically actuatedcontrol arrangement.
] Any degree of part-load capacity at any headcondition can be accepted without duress for anyperiod of time. The screw compressor actuallyoperates cooler at part-load conditions.
Positive Motor Alignment -The compressor isdirectly connected to the motor without anycomplicated gear systems to speed up thecompressor and thus detract from, the overall unitreliability. Factory alignment of motor andcompressor shafts eliminates the need for fieldadjustment.
Thrust Bearings -Each rotor is fitted with a pairof preloaded, duplex mounted angular contact thrustbearings.These bearings can also safely carry thrust in eitherdirection at or near zero thrust loads. Additionallythe bearing races are mechanically locked to assurezero race rotation.Through the use of hydraulic counterbalancearrangements, the thrust bearings carry only a smallportion of the total thrust generated. This combinedsystem for carrying the thrust load is not affected byemergencies such as power outage, low oil pressuretrip-out or similar incidents.
Main Journal Bearings -Heavy duty, steelbacked, machined in place babbitt bearings areconservatively loaded even at maximum operatingconditions. These bearings are center fed andsupplied with lubricant by an independently drivenoil pump. Start-up lubrication is provided and "coastdown" lubrication is not required as the screwcompressor stops within a matter of seconds.
Rotors -The latest asymmetrical design rotorprofiles assure operation at highest efficiencies.Rotors are precision machined from AISI 1141 barstock and dynamically balanced.
Castings -Castings are manufactured with highgrade, low porosity cast iron, externally ribbed forstructural stability and efficient heat dissipation.
Shaft Seal -An oil flooded, mechanical, processtype, balanced shaft seal effectively seals the driverotor and provides a long operating life.
Oil Cooling -Shaft seal oil is cooled by arefrigerant cooled oil cooler requiring nomaintenance or adjustment. Cool oil to the shaft sealinsures long shaft life and reduced maintenance.
SafetyCoupling
Guard
Open Type(Direct Drive)
MotorDischarge
PortJournal
BearingsSlideValve
UnloaderPiston
ThrustBalancing
Piston
SuctionPort
JournalBearings
MatchedRotors
ThrustBearings
ShaftSeal
MotorCoupling
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UNIT FEATURES COMPRESSOR
Compressor OperationNote: For clarity reasons, the following account ofthe compressor operation will be limited to one lobeon the male rotor and one interlobe space on thefemale rotor. In actual operation, as the rotorsrevolve, all of the male lobes and female interlobespaces interact similarly with resulting uniform,non-pulsating gas flow.
Suction PhaseAs a lobe of the male rotor begins to unmesh froman interlobe space in the female rotor, a void iscreated and gas is drawn in tangentially through theinlet port -Fig. A. As the rotors continue to turn, theinterlobe space increases in size -Fig. B, and gasflows continuously into the compressor. Before thepoint at which the interlobe space leaves the inletport, the entire length of the interlobe space iscompletely filled with drawn-in gas -Figure C.
Compression PhaseAs rotation continues, the gas in the interlobe spaceis carried circumferentially around the compressorhousing. Further rotation meshes a male lobe withthe interlobe space on the suction end and squeezes(compresses) the gas in the direction of thedischarge port. Thus the occupied volume of thetrapped gas within the interlobe space is decreasedand the gas pressure consequently increased.
Discharge PhaseAt a point determined by the designed "built-in"compression ratio, the discharge port is uncoveredand the compressed gas is discharged by furthermeshing of the lobe and interlobe space -Fig. D.While the meshing point of a pair of lobes is movingaxially, the next charge is being drawn into theunmeshed portion and the working phases of thecompressor cycle are repeated.
CAPACITY CONTROL SYSTEM
Figures A & B show the capacity control slide valvewithin the rotor housing. Axial movement of thisvalve is programmed by an exclusive Dunham-Bushelectrically initiated (by variations in leaving chilledwater temperature) hydraulically actuated controlarrangement. When the compressor is fully loaded,the slide valve is in the closed position (Figure A).Unloading starts when the valve is moved backaway from the valve stop (Figure B). Movement ofthe valve creates an opening in the bottom of the
rotor housing. Suction gas can then pass back fromthe rotor housing to the inlet port area before it hasbeen compressed. Since no significant amount ofwork has been done on this return gas, noappreciable power losses are incurred. Reducedcompressor capacity is obtained from the gasremaining in the rotors which is compressed in theordinary manner. Capacity reduction down to 10%of full load is possible by progressive movement ofthe slide valve away from the valve stop.
OutletFace
Slide ValvePartially Open
InletFace
RotorHousing
InletFace
Outlet FaceSlide Valve Fully
Closed FullCapacity
RotorHousing
Slide Valve/Rotor Housing Inlet End Slide Valve/Rotor Housing Inlet End
Figure A Figure B
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UNIT FEATURES COMPRESSOR
Capacity ControlThe advanced microprocessor supplies power to the load solenoid valve (LSV) and unload solenoid valve(USV) to control the position of the compressor slide valve piston. Control is achieved by monitoringleaving chilled fluid temperature. The sophisticated microprocessor will always so to meet a specific loaddemand and stabilize unit operation.
Compressor Loading
Loading - When energized, the load solenoid valve (LSV) opens and discharge pressure pushes the slidevalve towards load, forcing oil out of the cylinder into the suction housing.
Compressor Unloading
Unloading -When energized, the unload solenoid valve (USV) opens. The combination of discharge plusoil pressure on the slide valve piston will move the slide valve toward the unload position.
Compressor Part -Load
Part-Load -The unit will remain in the part-load position as long as the leaving chilled fluid temperatureremains at the desired temperature. Both load and unload solenoid valves will be closed and the pistonwill be stationary at the part-load position.
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UNIT FEATURES MICROCOMPUTER CONTROL
Advanced Microcomputer Control is a standardfeature on all Dunham-Bush Rotary Screw Chillersmonitoring analog and digital inputs to achieveprecise control of the major operational andprotective functions of the unit.
Direct digital control (DDC) allows finger-tip userinteraction. Its simple-to-use push button keyboardand menu-driven software provide access tooperating conditions, control setpoints and alarmhistory clearly displayed on a prominent multi-line80 character alphanumeric display.
An easy-to-install, inexpensive modem optionallows remote reading of operating parameterupdates. The Dunham-Bush microcomputer insuresits owner state-of-the-art efficiency and reliability.
Display InformationThe 80 character alphanumeric liquid crystal display utilizes easy-to-understand menu-driven software.Inexperienced operators can quickly work through these menus to obtain the information they require orto modify control parameters. More experienced operators can bypass the menu systems, if desired, andmove directly to their requested control function. At all times, assistance is available to the operator bysimply pressing the help key. Easily accessible measurements include:] Leaving chilled water temperature.] Evaporator pressure.] Condenser pressure.] Oil pressure.] Compressor amp draw.] Compressor elapsed run time.] Percent of slide valve loading.] Reservoir oil temperature] Seal oil temperature] Water temperature reset value] Demand limit reset value] Compressor starter status] Oil pump starter status] Water flow switch status] External start 1 stop command status
Optional entering chilled water temperature sensor is available, as well as entering and leaving condenserwater temperature sensors. With this option the operator can quickly and accurately read the watertemperatures and eliminate the need for often inaccurate thermometers.
Capacity ControlLeaving chilled water temperature control is accomplished by entering the water temperature setpoint andplacing the microcomputer in automatic control. The unit will monitor all control functions and move theslide valve to the required operating position. The compressor ramp (loading) cycle is programmable andmay be set for specific building requirements. Remote adjustment of the leaving chilled water setpoint isaccomplished through either direct connection via terminal or modem connected to the RS232communication port, or from an external Building Automation System supplying a simple 0 to 5VDCsignal. Remote reset of compressor current limit may be accomplished in a similar fashion.
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UNIT FEATURES MICROCOMPUTER CONTROL
System ControlThe unit may be started or stopped manually, or through the use of an external signal from a BuildingAutomation System. In addition, the microcomputer may be programmed with a seven-day operatingcycle or other Dunham-Bush control packages may start and stop the system through connection with theRS485 long distance differential communications port.
System ProtectionThe following system protection controls will automatically act to insure system reliability:
] Low suction pressure
] High discharge pressure
] Low oil temperature
] Freeze protection
] High receiver oil temperature
] High seal oil temperature
] Compressor starter failure
] Oil pump starter failure
] Compressor run error
] Power loss
] Chilled water flow loss
] Sensor error
] Compressor overcurrent
] Anti-recycle
The microcomputer will retain the latest eight alarm conditions complete with time of failure in an alarmhistory. This tool will aid service technicians in troubleshooting tasks, minimizing downtime.
Remote Monitoring CapabilityThe microcomputer is complete with an RS232 communications port and all hardware necessary toremotely monitor and control the packaged chiller up to 50 feet away (hard wired) or by optional phonemodem to extended distance. This valuable enhancement to the refrigeration system allows the ultimatein serviceability. The microcomputer as standard is additionally equipped with history files which may beused to take logs which may be retrieved via the phone modem periodically. Now owners of multiplebuildings have a simple and inexpensive method of investigating potential problems quickly and in ahighly cost effective manner.There are three methods of remote monitoring and operating of our package chillers.1. The RMDT (Remote Monitor Display Terminal) can be hard wired up to 50 feet away from the chiller
or connected through a modem for remote monitoring and operating of multiple chillers. The RMDTis supplied with a 14" monitor, two RS232 serial ports, a 6 foot 115 volt power cord and an enhancedPC keyboard.
2. An IBM PC Compatible computer with communication software installed (simple terminal) caninterface with the chiller in the same manner as the RMDT (Remote Monitor Display Terminal).
3. A BMS (Building Management System) may interface with the chiller microcomputer and provide thesame level of monitoring and operating control as above, when the BMS company has implementedthe communications protocol. Dunham-Bush has an open communications protocol policy with mostBMS companies.
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UNIT FEATURES PART -LOAD PERFORMANCE
Dunham-Bush Rotary Screw Water Chillers possess superior part-load performance characteristics. Thisis accomplished with the infinite capacity control capability of the slide valve equipped compressor.
Actual building system loads are significantly less than full load design conditions, therefore chillersoperate at full for a fraction of the operating time.
Dunham-Bush Rotary Screw Water Chillers combine the efficient operation of the rotary screwcompressor with finite refrigerant management and micro- processor control to yield the best total energyefficiency and significant operating savings under any load.
When specifying air conditioning equipment it is important to consider the system load characteristics ofthe building application. In a typical city, the air conditioning load will vary according to changes in theambient temperature. Weather data compiled over many years will predict the number of hours thatequipment will operate at various load percentages.
The Air Conditioning and Refrigeration Institute (ARI) has established a system, in ARI 550/590-98, formeasuring total chiller performance over full and part- load conditions. The Integrated Part-Load Value(IPLV) is an excellent method of comparing diverse types of equipment on an equal basis. The IPLV is asingle number estimate of a chiller's power use weighted for the number of hours the unit might spend ateach part-load point. IPLV's are based on Standard ARI Rating Conditions.
SI Metric Units
IPLVor = 0.01A + 0.42B + 0.45C + 0.12DAPLV
U.S. Standard Units
IPLV 1
or = 0.01 + 0.42 + 0.45 + 0.12
APLV A B C D
where:A=kW/ton [or EER] at 100% load pointB=kW/ton [or EER] at 75% load pointC=kW/ton [or EER] at 50% load pointD=kW/ton [or EER] at 25% load point
Application Part-Load Values (APLV) also give a single number estimate for the part-load performanceof a chiller but at Selected Application Rating Conditions.
Integrated Part-Load Values and Application Part-Load Values are available from your Dunham-BushRepresentative and will be calculated for your specific conditions. These points, as well as the full loadselection point, are all according to the ARI Large Tonnage Certification Program for Centrifugal andRotary Screw Water-Chilling Packages.
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TYPICAL SEQUENCE OF OPERATION
The Dunham-Bush Rotary Screw Water Chillerdepends mainly on its on-board microcomputerfor control. For initial start-up, the followingconditions must be met:
] Chilled water pump running] Chilled water flow switch made] Customer (optional) control contact closed] Control and compressor switch on] Circuit breakers on] All safety conditions satisfied] Reset pressed on microcomputer keypad] Compressor has not started within the last 20
minutes] Leaving chilled water temperature 2°F(1/2°C)
or more above set point] Oil sump temperature is greater than
70°F(21°C)
The microcomputer starts the oil pump byenergizing 4CP. If capacity indicator is below 8%and a minimum of 27 psig (186 kPa) oil pressureis established, seconds later the microcomputersignals 2CR which starts the compressor motor.When the compressor starts, the microcomputermonitors leaving water temperature, rampschedule, and load limiting to control load andunload solenoids. The refrigerant level sensor anddischarge temperature are used to control therefrigerant modulating motor. When minimumcompressor capacity exceeds system load andwater temperature falls below set point, thecompressor and oil pump are shut down.The control system is composed of fourmicrocomputer boards, a display board andanalog and digital sensors. The display board hasa 20-key keypad and a 2 x 40 LCD display. Thekeypad and display can be used to determine thestatus of the compressor, oil pump, andrefrigeration system. Various set points can alsobe displayed and altered.The status of the machine can also be monitoredby a computer terminal either locally or remotelyby a modem. The terminal must be able to handleRS232 communications.The microcomputer controls the leaving watertemperature within a narrow dead band by pulsingload and/or unload solenoids on the compressor.The load and unload solenoids position thecompressor's slide valve to control the capacity.The microcomputer determines a desired level ofloading and varies pulse duration depending on
the difference between load target and actual load.The load target is varied based on rate ofapproach to desired temperature (derivativecontrol) preventing significant temperatureoscillations. The current limit functions over-ridethe temperature control.
On packages with wye-delta starters, a refrigerantbypass is used to start unit. The microcomputerturns the bypass solenoid on when the oil pumpstarts and turns it off 30 seconds after thecompressor starts.
Another feature of the microcomputer is rampcontrol, which is the ability to vary load time ofthe package from start. The user can program thecomputer so that it loads at a pre-determined rate.Two variables are used to define the ramp profile:Ramp Rate and Start Point. Ramp rate defines thelength of time the unit takes to load from startpoint to full load. Start point is the point of fullload at which the ramp begins.
When optional hot gas bypass has been supplied,an output from the computer controls thesolenoid. The solenoid is turned on if the targetpercent capacity of the compressor drops belowthe hot gas bypass set point. If the target percentcapacity then climbs above the set point. Thesolenoid is turned off.
When a maximum desired current is specified byamp limit, the compressor will not load above thatpoint. If the amps rise above the set point, thecomputer will give an unload signal to thecompressor until the current drops below the setpoint.
If desired, the chilled water temperature can be(optionally) raised by a 0-5 VDC analog signalprovided by an external controller. The resetsignal must be between 0 VDC and 5 VDC, with0 VDC being no reset and 5 VDC beingmaximum reset. The maximum temperature reset(increase) desired must be stored in CWR MAX.For example, to raise the chilled water set pointfrom 44"F (6. TC) to 50°F(10°C with a 5 VDCinput, 6.0(3.3) is stored in CWR MAX.
If (optional) demand limiting is desired, a 0 to 5VDC signal must be supplied to the DemandLimit terminals shown on the wiring diagram.Supplying 0 volts will have no effect, and 5 voltswill have maximum limiting. The demand limitworks automatically lowering the HOLD andUNLOAD amp limits for the compressor. Thisdoes not change the amp limit set points.
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DIMENSIONAL DATA
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DIMENSIONAL DATA
DIMENSIONS-Inch [mm]
Model Evap Cond A B C C1 D D1 E F G
®® J4 F5 73 79 1/8 178 3/4 [4540] 183 1/4 [4655] 5 [127] 8 1/8 [206] 20 1/4 [514] 17 1/8 [435] 8 5/8 [219]056 ×× K5 G5 77 [1956] 81 1/8 [2061] 178 3/4 [4540] 183 1/4 [4655] 5 [127] 8 1/8 [206] 22 [559] 19 [483] 8 5/8 [219]
M5 H5 79 [2007] 83 1/8 [2111] 177 1/4 [4502] 181 1/4 [4604] 5 [127] 5 [127] 24 [610] 20 [508] 8 5/8[219]N5 J5 82 3/8 [2092] 85 1/8 [2162] 184 1/2 [4686] 189 [4801] 9 [229] 12 3/4 [324] 25 1/2 [648] 21 [533] 10 1/4 [260]
®® K5 G5 77 [1956] 81 1/8 [2061] 178 3/4 [4540] 183 1/4 [4655] 5 [127] 8 1/8 [206] 22 [559] 19 [483] 8 5/8 [219]066 ×× M5 H5 79 [2007] 83 1/8 [2111] 177 1/4 [4502] 181 1/4 [4604] 5 [127] 5 [127] 24 [610] 20 [508] 8 5/8[219]
N5 J5 82 3/8 [2092] 85 1/8 [2162] 184 1/2 [4686] 189 [4801] 9 [229] 12 3/4 [324] 25 1/2 [648] 21 [533] 10 1/4 [260]P5 K5 84 1/8 [2137] 87 1/8 [2211] 177 1/4 [4502] 181 1/4 [4604] 5 [127] 5 [127] 26 1/2 [673] 22 [559] 10 1/4 [260]
®® M5 H5 79 [2007] 83 1/8 [2111] 177 1/4 [4502] 181 1/4 [4604] 5 [127] 5 [127] 24 [610] 20 [508] 8 5/8[219]
080 ×× N5 J5 82 3/8 [2092] 85 1/8 [2162] 184 1/2 [4686] 189 [4801] 9 [229] 12 3/4 [324] 25 1/2 [648] 21 [533] 10 1/4 [260]P5 K5 84 1/8 [2137] 87 1/8 [2211] 177 1/4 [4502] 181 1/4 [4604] 5 [127] 5 [127] 26 1/2 [673] 22 [559] 10 1/4 [260]S5 L5 89 1/4 [2267] 89 1/8 [2264] 181 1/4 [4604] 185 3/4 [4718] 5 [127] 9 [229] 28 1/2 [724] 23 [584] 10 3/4 [273]
®® N4 J3 82 3/8 [2092] 90 1/2 [2299] 184 1/2 [4686] 189 [4801] 9 [229] 12 3/4 [324] 25 1/2 [648] 21 [533] 10 1/4 [260]
089 ×× N5 J5 82 3/8 [2092] 90 1/2 [2299] 184 1/2 [4686] 189 [4801] 9 [229] 12 3/4 [324] 25 1/2 [648] 21 [533] 10 1/4 [260]P5 K5 84 1/8 [2137] 92 1/4 [2350] 177 1/4 [4502] 181 1/4 [4604] 5 [127] 5 [127] 26 1/2 [673] 22 [559] 10 1/4 [260]S5 L5 89 1/4 [2267] 94 1/2 [2400] 181 1/4 [4604] 185 3/4 [4718] 5 [127] 9 [229] 28 1/2 [724] 23 [584] 10 3/4 [273]
107 ®® P5 K5 84 1/8 [2137] 95 3/4 [2432] 177 1/4 [4502] 181 1/4 [4604] 5 [127] 5 [127] 26 1/2 [673] 22 [559] 10 1/4 [260]×× S5 L5 89 1/4 [2267] 97 3/4 [2483] 181 1/4 [4604] 185 3/4 [4718] 5 [127] 9 [229] 28 1/2 [724] 23 [584] 10 3/4 [273]
Model Evap Cond H J K L M N P Q T
®® J4 F5 1 3/4 [44] 10 3/8 [264] 16 [406] 5 1/2 [140] 12 3/4 [324] 82 [2083] 5 1/4 [133] 6 7/8 [175] 5 [127]
056 ×× K5 G5 1 3/4 [44] 10 3/8 [264] 17 [432] 6 7/8 [175] 14 [356] 86 [2184] 5 1/4 [133] 6 7/8 [175] 5 [127]
M5 H5 3 3/4 [95] 12 1/4 [311] 19 [483] 7 3/8 [187] 15 [[381] 86 [2184] 6 3/8 [162] 6 7/8 [175] 5 [127]
N5 J5 5 1/4 [133] 13 3/4 [349] 20 1/2 [521] 8 [203] 16 [406] 87 1/4 [2216] 6 1/4 [159] 6 7/8 [175] 5 [127]®® K5 G5 1 3/4 [44] 10 3/8 [264] 17 [432] 6 7/8 [175] 14 [356] 86 [2184] 5 1/4 [133] 6 7/8 [175] 5 [127]
066 ×× M5 H5 3 3/4 [95] 12 1/4 [311] 19 [483] 7 3/8 [187] 15 [[381] 86 [2184] 6 3/8 [162] 6 7/8 [175] 5 [127]
N5 J5 5 1/4 [133] 13 3/4 [349] 20 1/2 [521] 8 [203] 16 [406] 87 1/4 [2216] 6 1/4 [159] 6 7/8 [175] 5 [127]
P5 K5 6 1/4 [159] 13 5/8 [346] 21 1/2 [546] 8 1/8 [206] 16 5/8 [422] 89 5/8 [2283] 6 7/8 [175] 6 7/8 [175] 5 [127]®® M5 H5 3 3/4 [95] 12 1/4 [311] 19 [483] 7 3/8 [187] 15 [[381] 86 [2184] 6 3/8 [162] 6 7/8 [175] 5 [127]
080 ×× N5 J5 5 1/4 [133] 13 3/4 [349] 20 1/2 [521] 8 [203] 16 [406] 87 1/4 [2216] 6 1/4 [159] 6 7/8 [175] 5 [127]
P5 K5 6 1/4 [159] 13 5/8 [346] 21 1/2 [546] 8 1/8 [206] 16 5/8 [422] 89 5/8 [2283] 6 7/8 [175] 6 7/8 [175] 5 [127]
S5 L5 8 1/4 [210] 15 5/8 [397] 23 1/2 [597] 8 7/8 [225] 18 [457] 91 1/4 [2318] 6 7/8 [175] 6 7/8 [175] 5 [127]®® N4 J3 5 1/4 [133] 13 3/4 [349] 20 1/2 [521] 8 [203] 16 [406] 103 1/4 [2613] 6 1/4 [159] 6 7/8 [175] 5 [127]
089 ×× N5 J5 5 1/4 [133] 13 3/4 [349] 20 1/2 [521] 8 [203] 16 [406] 103 1/4 [2613] 6 7/8 [175] 6 7/8 [175] 5 [127]
P5 K5 6 1/4 [159] 13 5/8 [346] 21 1/2 [546] 8 1/8 [206] 16 5/8 [422] 101 1/2 [2578] 6 7/8 [175] 6 7/8 [175] 5 [127]S5 L5 8 1/4 [210] 15 5/8 [397] 23 1/2 [597] 8 7/8 [225] 18 [457] 103 1/8 [2619] 6 7/8 [175] 6 7/8 [175] 5 [127]
107 ®® P5 K5 6 1/4 [159] 13 5/8 [346] 21 1/2 [546] 8 1/8 [206] 16 5/8 [422] 103 1/8 [2619] 6 7/8 [175] 6 7/8 [175] 5 [127]
×× S5 L5 8 1/4 [210] 15 5/8 [397] 23 1/2 [597] 8 7/8 [225] 18 [457] 101 1/8 [2569] 6 7/8 [175] 6 7/8 [175] 5 [127]®® Standard Vessel Set – 50Hz ×× Standard Vessel Set – 60Hz
VICTAULIC WATER CONNECTION SIZES – INCHES [mm]
VESSEL CODE EVAPORATOR VESSEL CODE CONDENSER
1 PASS 2 PASS 3 PASS 1 PASS 2 PASS
J4 14 [356] 10 [254] 8 [203] F5 12 [305] 8 [203]
K5 14 [356] 10 [254] 8 [203] G5 14 [356] 10 [254]
M5 14 [356] 10 [254] 8 [203] H5 14 [356] 10 [254]
N4 16 [406] 12 [305] 8 [203] J3 16 [406] 12 [305]N5 16 [406] 12 [305] 8 [203] J5 16 [406] 12 [305]
P5 18 [457] 12 [305] 10 [254] K5 18 [457] 12 [305]
S5 18 [457] 14 [356] 10 [254] L5 18 [457] 14 [356]
NOTES:1. WATER PIPING TO BE SUPPORTED TO MINIMIZE LOAD ON UNIT.2. ALL DIMENSIONS ARE IN INCHES AND [MILLIMETERS].3. IF CONDENSER AND EVAPORATOR ARE 1 OR 3 PASS SEE DETAIL ‘A’ FOR HEAD LENGTH. TO CALCULATE THE OVERALL LENGTH OF THE UNIT
WHEN USING 1 OR 3 PASS VESSELS. ADD 158 [4013] TO THE LONGER HEAD ON EACH SIDE.4. VENT AND DRAIN CONNECTIONS PROVIDED ON EVAPORATOR AND CONDENSER HEADS.5. IF A DOORWAY OR OTHER PROPERLY LOCATED OPENING IS USED FOR TUBE REMOVAL. THE SUGGESTED MINIMUM CLEARANCE IS 36"[914].6. SUFFICIENT ROOM MUST BE ALLOWED FOR EVAPORATOR AND CONDENSER CONNECTIONS.7. SUGGESTED CLEARANCES AROUND THE MACHINE ARE MINIMUM REQUIREMENTS. IT IS STRONGLY RECOMMENDED THAT AT LEAST ONE OF
THESE CLEARANCE REQUIREMENTS EXCEED THE MINIMUM TO ALLOW FOR COMPRESSOR OR MOTOR SERVICING.8. WHEN LOOKING AT 2 PASS EVAPORATOR HEAD CONNECTIONS, WATER OUTLET IS LEFT CONNECTION. WATER INLET IS RIGHT
CONNECTION, AS SUPPLIED BY FACTORY. CUSTOMER MAY REVERSE THIS ARRANGEMENT, BUT LEAVING WATER TEMPERATURE SENSORMUST BE RELOCATED TO WATER OUTLET.
9. WATER CONNECTIONS OF 1 PASS VESSELS ARE ON CENTER LINE OF VESSEL. FOR EVAPORATOR USE DIMENSION E AND K . FORCONDENSER USE DIMENSION F AND M.
10. DIMENSION N ACCOMMODATES OIL SEPARATOR OVERHANG AND MOTOR OVERHANG.
- 13 -
PHYSICAL SPECIFICATIONS
50 Hz
UNIT MODEL 056AUJ4F5 066AUK5G5 080AUM5H5 089AUN4J3 107AUP5K5
NOMINAL TONS * 431 514 620 686 826
COMPRESSOR 2510 2512 2515 2516 2519
RPM 2950 2950 2950 2950 2950
EVAPORATOR MODEL J4 K5 M5 N4 P5
DESIGN PRESS. WATER SIDE (PSIG) 150 150 150 150 150
DESIGN PRESS. REFRIG. SIDE (PSIG) 260 260 260 260 260
WATER VOLUME, GALLONS 100 119 145 162 194
MIN. GPM (1 PASS) 715 845 1000 1153 1366
MIN. GPM (2 PASS) 357 416 500 571 670
MIN. GPM (3 PASS) 232 260 320 380 430
MAX. GPM (1 PASS) 3574 4260 5104 5711 6830
MAX. GPM (2 PASS) 1787 2100 2500 2856 3400
MAX. GPM (3 PASS) 1161 1300 1600 1898 2248
CONDENSER MODEL F5 G5 H5 J3 K5
DESIGN PRESS. WATER SIDE (PSIG) 150 150 150 150 150
DESIGN PRESS. REFRIG. SIDE (PSIG) 260 260 260 260 260
WATER VOLUME, GALLONS 88 105 131 148 178
MIN. GPM (1 PASS) 712 870 1020 1183 1416
MIN. GPM (2 PASS) 357 424 520 592 700
MAX. GPM (1 PASS) 3559 4350 5260 5914 7050
MAX. GPM (2 PASS) 1784 2170 2600 2962 3500
GENERAL INFORMATION
SHIPPING WT. LB. 22524 26311 30716 34210 39131
OPERATING WT. LB 24131 28284 33132 37109 42397
APPROX. REFRIGERANT CHARGE, LB. R-22 988 1171 1417 1558 1867
* Actual capacities will depend on specified operating conditions. To consult nearest Dunham-Bush sales office for computer selections.
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PHYSICAL SPECIFICATIONS
60 Hz
UNIT MODEL 056ARK5G5 066ARM5H5 080ARN5J5 089ARP5K5 107ARS5L5
NOMINAL TONS * 519 618 746 824 992
COMPRESSOR 2510 2512 2515 2516 2519
RPM 3550 3550 3550 3550 3550
EVAPORATOR MODEL K5 M5 N5 P5 S5
DESIGN PRESS. WATER SIDE (PSIG) 150 150 150 150 150
DESIGN PRESS. REFRIG. SIDE (PSIG) 260 260 260 260 260
WATER VOLUME, GALLONS 119 145 175 194 234
MIN. GPM (1 PASS) 852 1022 1234 1366 1646
MIN. GPM (2 PASS) 426 511 617 683 823
MIN. GPM (3 PASS) 273 332 408 448 546
MAX. GPM (1 PASS) 4260 5104 6168 6830 8224
MAX. GPM (2 PASS) 2130 2552 3084 3415 4112
MAX. GPM (3 PASS) 1303 1560 1909 2166 2625
CONDENSER MODEL G5 H5 J5 K5 L5
DESIGN PRESS. WATER SIDE (PSIG) 150 150 150 150 150
DESIGN PRESS. REFRIG. SIDE (PSIG) 260 260 260 260 260
WATER VOLUME, GALLONS 105 131 156 178 210
MIN. GPM (1 PASS) 876 1054 1262 1416 1688
MIN. GPM (2 PASS) 438 527 631 710 844
MAX. GPM (1 PASS) 4382 5272 6308 7087 8436
MAX. GPM (2 PASS) 2191 2636 3154 3539 4218
GENERAL INFORMATION
SHIPPING WT. LB. 26161 30560 34016 38881 44992
OPERATING WT. LB 28134 32976 36915 42147 48888
APPROX. REFRIGERANT CHARGE, LB. R-22 1185 1405 1700 1870 2240
* Actual capacities will depend on specified operating conditions. To consult nearest Dunham-Bush sales office for computer selections.
- 15 -
0.1
1
1 0
1 0 0
1 0 0 1 0 0 0 1 0 0 0 0
W A T E R F L O W R A T E - G P M
1
1 0
1 0 0
1 0 0 1 0 0 0 1 0 0 0 0
W A T E R F L O W R A T E - G P M
J 4
K 5
M 5
N 4
N 5
P 5
S 5
1
1 0
1 0 0
1 0 0 1 0 0 0 1 0 0 0 0
W A T E R F L O W R A T E - G P M
1 P A S S
2 P A S S
PRESSURE DROP
1.) Evaporator 1 & 2 Pass
2.) Evaporator 3 Pass
3.) Condenser 1 & 2 Pass
2 PASS
1 PASS
J4
K5
M5
N4
N5
P5
S5
J4
K5
M5N4
N5
P5
S5
F5
G5
H5
J3
J5
K5
L5
F5
G5
H5
J3
J5
K5
L5
- 16 -
TYPICAL WIRING DIAGRAM
- 17 -
TYPICAL WIRING DIAGRAM
- 18 -
APPLICATION DATA HEAT RECOVERY
Head Pressure ControlNormal head pressure control is by cycling towerfan(s) as long as this can provide condenser enteringwater no lower than 60°F(15°C) with no more than a2°F(1/2°C) change per minute. If this cannot beguaranteed, then other controls such as towerdampers, tower sump heater, 3-way tower bypassvalve, 2-way tower throttling valve or variable speedcondenser pumping must be utilized. With anoptional analog output board, the microcomputer cancontrol the bypass or throttling valve directly fromcondenser pressure by sending a 0 to 10 VDC signalto a direct current valve motor actuator.The Dunham-Bush microcomputer can provide adigital signal to enable any of these devices so thatthe tower and its requested accessories can becontrolled by the chiller.Dunham-Bush Water-Cooled Chillers have asstandard a control feature called EPCAS (EvaporatorPressure Control at Start) which will allow for aninverted start. This occurs when the chilled waterloop in a building is at a higher temperature than thecondenser/tower loop. This occurs in many buildingsafter a weekend shut down. The chilled water loopcan be as high as 90°F/32°C and the condenser/tower loop as low as 60°F/16°C. With the EPCASfeature, the valve feeding the evaporator will bethrottled to create a pressure differential to help loadthe compressor.
Splittable UnitsWhere existing equipment room makes it difficult togo a new unit into the building, special fittings canbe provided. This will allow the unit(s) to beseparated Into (2) pieces at the job site to facilitateinstallation. Refrigerant charge can be removed afterfactory test or isolated in one of the vessels.
Chilled Water FlowThe Dunham-Bush WCOX Packaged Water Chilleris designed for a constant chilled water flow rateeven when the cooling load is varying. The machinewill generally perform satisfactorily with steadyflow rates deviating from design by as much as +10%/-50%. However, varying water flow rates cancause control instability which will result inundesirable system effects, particularly poor controlof leaving chilled water temperature. If two-wayvalves are used to control flow through cooling coils,some means such as an automatic modulating valveshould be provided in the system to maintain steadyflow through the cooler.If the chilled water system is arranged for the dualpurpose of cooling and heating, the cooler must
incorporate valves to prevent the flow of hot waterthrough it. This can be done with either manual orautomatic shutoff valves, but the method of controlmust be such that water temperature entering thecooler never exceeds 90°F/32°C.
Ice StorageWith a positive displacement rotary screwcompressor, the Dunham-Bush water chiller caneasily cool low temperature glycol down to 22°F/-6°C with entering condenser water of 85°F(29°C).The same chiller can also produce warmer (40°F/4°Cto 45°F/7°C) leaving glycol for those buildingsystems designed for only peak shaving. This can beaccomplished by an external signal to the unitmicrocomputer. No matter what your ice storageneeds, the Dunham-Bush Rotary Screw Water-Cooled Chiller can handle it better than any otherchiller.When used with Dunham-Bush Ice- Cels, themicrocomputer can be programmed to provide dualmode leaving chilled liquid set points for both airconditioning arid ice freezing duty, plus start andstop of chilled liquid and condenser pumps.In addition, the following thermal storage controlscan be provided.
a.) Freeze only
b.) Freeze plus cooling
c.) Cooling with ice only
d.) Cooling with chiller plus ice
e.) Cooling with chiller only
f.) Off
Plus they can provide daily scheduling of abovemodes in as many different daily schedules asdesired. These schedules can be assigned to days ofthe week and holidays.
Multiple Unit ControlOne of the most perplexing problems to systemdesigners is control of multiple chillers on the samewater loop. The first decision is whether to put thechillers in parallel or series on the chilled water side.If lower pumping cost is paramount, then puttingchillers in series is often preferable. Ifprimary/secondary pumping is utilized with normal10°F/6°C range, then putting chillers in parallel isnormally used. In either case, the Dunham-Bushmicrocomputer can control up to three chillers. Thiseliminates the need for external control interfacewhich often becomes difficult. If more than threechillers need to be controlled, a Utility Manager canbe supplied for controlling/monitoring up to tenunits.
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APPLICATION DATA HEAT RECOVERY
Condensing Water TreatmentCondensing water tends to leave silt, algae andmineral deposits in the condenser tubes. This foulinggradually decreases unit efficiency. For this reason, aprogram of water treatment should be employed.Also, at regular intervals depending an water quality,the unit should be shut down, condenser headsremoved and tubes cleaned.
FoundationA flat, level concrete foundation or floor capable ofsupporting the weight of the unit must be provided.The unit must be leveled to within 1/16 perfoot/1.6mm per 30.5cm for proper operation.
Vibration Isolation
Where structure- bor ne vibration may be of concern,
it is recommended that the unit be mounted on
vibration isolators. Spring isolators are available for
this unit as optional equipment. If spring isolators
are installed, it is also necessary to provide isolation
in condenser water and, chilled water pipes by
means of flexible connectors and in main power
supply conduit through use of flexible conduit.
Isolation of piping and electrical conduit is desirable
in any event to avoid noise transmission.
APPLICATION DATA POINT LOADINGS
POINT LOADINGS – LBS.-IN50 HZ
WCOX A B C D E F
056 5140 6298 5695 6998 64 166 3/4
066 6109 7184 6902 8089 68 166 3/4
080 7355 8482 8018 9277 70 166 3/4
089 8157 9277 9210 10465 73 3/8 166 3/4
107 9287 10450 10704 11956 75 1/8 166 3/4
60 HZ
056 5982 7340 6651 8161 68 166 3/4
066 7122 8370 8038 9446 70 166 3/4
080 8177 9462 8936 10340 73 3/8 166 3/4
089 9250 10550 10440 11907 75 1/8 166 3/4
107 10733 12041 12307 13807 80 1/4 166 3/4
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STANDARD EQUIPMENT AND FACTORYINSTALLED OPTIONS
Dunham-Bush Rotary Screw Water-CooledChillers, like many other Dunham-Bush products,distinguish themselves by offering as standardmany features that other manufacturers provideonly as costly options.
Some of the Standard Features of these chillerswhich provide for efficiency and reliability are:
] Industrial grade Dunham-Bush rotary screwcompressor with double acting slide valve forinfinite capacity control
] Suction and discharge check valves for ease ofmaintenance
] Open Drip Proof Squirrel Cage motor, factorymounted and aligned
] Microcomputer monitoring of cooler leavingwater temperature to ±1/2 to 3/4°F/C viaproportional derivative control
] Proactive microcomputer monitoring ofevaporator and condenser pressures to unloadcompressor if operation is approachingoperating limits
] Microcomputer monitoring of oil pressure,discharge temperature and evaporatorrefrigerant level to optimize unit performance
] One, two, or three pass evaporator and one ortwo pass condenser for flexibility in design
] Units shipped completely factory tested,charged and adjusted for ease of installationand minimal field start-up adjustments
] Chilled water reset from control panel orexternal building automation system
] High oil temp, high motor temp, low oil level,freeze, low suction pressure, high dischargepressure, and solid state overload protection areall featured
Dunham-Bush offers Factory Installed Optionsfor "custom solutions" to meet owner andoperator requirements:
] Insulation of all low temperature surfaces
] Double insulation for ice bank application
] Hot gas bypass for very low load situations
] Microprocessor monitoring of return chilledwater and entering and leaving condenser waterin addition to the standard leaving chilled watertemperature by the addition of factory mountedand wired temperature sensors
] Phone modem communication to simpleterminal or personal computer withcommunication software to enable the remotemonitoring of all functions and inputs to themicroprocessor
] Marine Water Boxes (on condensers only) ,with individual bolted-on cover platespermitting access for tube cleaning without"breaking" water piping connections
] Flanged Water Connections can be supplied onboth evaporator and condenser water in lieu ofstandard Victaulic connections
] Unit can be supplied with additional fittings toallow it to be split into two sections in field forspecial site conditions
] Computer graphics display with on-screen viewof the equipment and a real time display oftemperatures, pressures and device status
] Control of up to three packages requiring onlytwo shielded cables between units. Up to tenpackages can be controlled via a utilitiesmanager
] Special panel interlocks and controls can beprovided to meet local code or customerrequirements
] Skidding to allow movement of the unit with aforklift
- 21 -
GUIDE SPECIFICATION
GeneralThe contractor shall in accordance with the plans,furnish and Install ____________ Dunham-Bushpackaged liquid chiller(s), model number WCOX________ The unit(s) shall be completely factorypackaged including open drive rotary screwcompressor, factory mounted open drip-proof motor,evaporator, condenser, external oil separator,positive displacement open-drive oil pump, andmicrocomputer control center. The packaged chillershall be factory assembled, charged and tested witha full operating refrigerant and oil charge. Therefrigerant type shall be R-22.
CapacityCapacity of each shall not be less than refrigerationtons cooling _______ GPM of water from ________°F to ________ °F Power input requirements for theunit(s), incorporating all appurtenances necessaryfor unit operation, including but not limited to thecontrol accessories and oil pump or pumps, ifrequired, shall not exceed _________ kW input atdesign conditions. The unit(s) shall have an ARIIntegrated Part-Load Value (IPLV) [NOTE:"Application Part-Load Value (APLV)" if other thanARI Standard Conditions] that does not exceed________ when calculated at the above conditionsper ARI Standard 550/590-98. The unit shall be ableto unload to ____ % of cooling (refrigeration)capacity when operating with the leaving chilledwater and entering condenser water temperaturesmentioned above. The unit shall be capable ofcontinuous operation at this point, with stablecompressor operation, without the use of hot gasbypass. Heat transfer surfaces shall be selected toreflect the incorporation of a fouling factor of .0001and a maximum water pressure drop of ________feet through the evaporator. The condenser shall beselected with a fouling factor of .00025 and amaximum water pressure drop of __________ feet.
CompressorThe compressor shall be a single-stage open drive,positive displacement rotary screw compressor ofthe oil injected type, operating at no more than 3550RPM at 60 HZ (2960 RPM at 50 HZ). Thecompressor motor shall be of the open drip-proof,squirrel cage induction type, factory mounted forrigid alignment of compressor and motor shafts.Compressor rotors shall be of the asymmetricalprofiles and be precision machined from AISI 1141bar stock and dynamically balanced. The shaft sealshall be of the oil flooded, mechanical, process type.
Compressor capacity control shall be obtained by anelectrically initiated, hydraulically actuated slidevalve within the compressor housing.
Oil SystemThe compressor shall be provided with a completepressure fed lubrication system including a positivedisplacement gear type open-drive oil pumpindependently driven. Positive lubrication shall beprovided prior to compressor start-up. A replaceablecore oil filter shall be provided to filter 100% of theoil supplied to the compressor. System pressuredifferential oil systems will not be acceptable unlessthe packaged chiller's refrigerant managementsystem is equipped with the ability to modulaterefrigerant flow into the evaporator, allowing themicrocomputer to insure the proper minimum oilpressure for safe operation. Shaft seal oil shall becooled by a refrigerant cooled oil cooler to provideextended shaft seal life, a water-cooled oil coolermay only be utilized if it is of the cleanable type.
EvaporatorThe evaporator shall be of the cleanable "shell andtube" flooded type with integral finned copper tubesmechanically expanded into heavy fixed steel tubesheets. Tubes shall be high efficiency, internallyenhanced type. It is to be available in one, two orthree-pass design as indicated on the drawings withvictaulic water connections. Flanges or stub-outwater connections will not be acceptable. The shellside of the evaporator is to be equipped with a singlepressure relief device and shall be designed, andconstructed in accordance with the ASME code forUnfired Pressure Vessels. The evaporator shall alsohave a built-in distributor for feeding refrigerantevenly under the tube bundle to produce a uniformboiling action and baffle plates shall be provided toensure vapor separation. Water heads are to beremovable for tube cleaning. Vent and drain plugsare to be provided in each head. The evaporatorshall be fitted with an oil recovery system. The oilrecovery system will insure that the evaporator isoperating at peak efficiency at all times. Unitswithout oil recovery systems mounted externally onthe evaporator will not be acceptable.
CondenserThe condenser shall be of the cleanable "shell andtube" type with integral finned copper tubesmechanically expanded into heavy fixed steel tubesheets. Tubes shall be a high efficiency, internallyenhanced type. They are to be available in one, or
- 22 -
GUIDE SPECIFICATION
two-pass design as indicated on the drawings withVictaulic water connections. Flanges or stub-outwater connections will not be acceptable. The shellside of the condenser is to be equipped with dualpressure relief devices and shall be designed,constructed, and stamped in accordance with theASME Code for Unfired Pressure Vessels. Thecondenser shall be sized for full pump downcapacity. Water heads are to be removable for tubecleaning. Vent and drain plugs are to be provided ineach head.
Oil SeparatorAn oil separator shall be provided between thecompressor and condenser. The oil separator shallhave no moving parts and shall achieve separationof refrigerant and oil through gravity drop-out. Finemesh eliminators will be provided for finalseparation. Multiple thermostatically controlledimmersion heaters shall be provided in the oilreservoir to insure the separation of refrigerant andoil and shall be automatically energized uponshutdown of the compressor.
Refrigerant Control SystemThe packaged chiller shall be furnished with a finiterefrigerant control system to optimize efficiency andcompressor protection. This refrigerant controlsystem will prevent the flow of efficiency robbingrefrigerant vapor in the condenser from entering theevaporator at reduced load by directly modulating amotorized refrigerant valve in the liquid lineentering the evaporator. In addition, the refrigerantcontrol system shall measure the level of liquidrefrigerant in the flooded evaporator and restrictrefrigerant flow entering the evaporator upon a risein the level, protecting the compressor fromslugging liquid refrigerant. Fixed orifice ice controlsystems will not be acceptable.
Microcomputer ControlThe packaged chiller shall be equipped withmicrocomputer control. The control shall providefor compressor loading based on leaving chilledwater temperature. It shall provide for high and lowrefrigerant pressure protection, low oil pressureprotection, evaporator water freeze protection, highreservoir oil temperature or seal oil temperatureprotection, incomplete start protection sensor errorprotection, and motor load control (demand limiter)based on amp draw. Anti-recycle protection shallalso be provided. The computer shall have a simplekeyboard accessed input system and be completewith a two line 80 character alphanumeric display.Input shall be accomplished through simple menu
driven display screens, with on-line help availableby pressing a help button at anytime duringoperation. The microcomputer shall continuouslymonitor evaporator leaving water temperature;evaporator, condenser and oil pressure; compressoramp draw: compressor slide valve position; oilreservoir temperature: seal oil temperature. Thecomputer shall be complete with all hardware andsoftware necessary to enable remote monitoring ofall data through the addition of only a simple,optional, phone modem and terminal. Themicrocomputer shall be complete with an RS232"local" communications port and an RS485 longdistance differential communications port. Themicrocomputer shall also accept a remote start andstop signal, 0 to 5VDC chilled water temperaturereset signal and 0 to 5VDC compressor current limitreset signal.
Electrical Control PanelThe electrical control panel shall be wired to permitfully automatic operations during initial start-upsnormal operations, and shutdown conditions. Thecontrol system shall contain the following controland safety devices:
Manual Controls] Control circuit stop and start switches] Compressor enable switch
Safety Controls] Low oil pressure] High oil reservoir temperature] High seal oil temperature] High condenser pressure] Low evaporator pressure] Freeze protection] Chilled water flow loss
Automatic Controls] Compressor starter transition timer] Anti-recycle timer] Oil reservoir heater interlock
Refrigerant Controls] Finite refrigerant motorized refrigerant valve] Liquid refrigerant level sensor for evaporator] Compressor load and unload solenoid valves
Indicator Lights] Power on] Compressor enabled] Alarm
- 23 -
