HVAC Guide Specifications
Single-Effect, Steam Hermetic AbsorptionLiquid Chillers
SizeRange:
100 to 700 Tons
Carrier-Sanyo Model Number:
16TJ
Part 1 — General
1.01 SYSTEM DESCRIPTION
Electronically controlled, single effect (one-stage) absorptionliquid chiller utilizing hermetic refrigerant and absorbentpumps, lithium bromide solution as the absorbent,and water as the refrigerant. Low pressure steam shall besupplied to the generator as the heat source.
1.02 QUALITY ASSURANCE
A. Chiller performance shall be rated in accordancewith ARI Standard 560-2000.
B. Chiller shall be manufactured in accordance withANSI/ASHRAE 15 (latest edition) Safety Code forMechanical Refrigeration.
C. Chiller shall be designed and constructed to meetapplicable UL requirements and shall bear the ULlabel.
D. Each chiller shall undergo a series of standard factorytests to ensure that the unit is leak tight, that allelectrical components operate as intended, and thatevery aspect of unit fabrication meets stringent qualitystandards in accordance with good practice andthe manufacturer's quality assurance requirements.
1. The shellside of each chiller shall be leak testedby pressurizing to 7 psig with nitrogen and thenchecked by spraying a soap and water mixtureon all welds, tube joints and/or gasketed jointsto identify any major leaks. Afterward, a massspectrometer test shall be performed by evacuatingthe unit to 0.01 mm Hg absolute, coveringthe machine with a vinyl tent andintroducing helium gas under the tent. Anyremaining leaks will allow the helium to bedrawn into the shellside of the machine. Theacceptable total leak rate as measured by themass spectrometer test shall not exceed.000002 cc/sec standard air.
2. The tubeside of the evaporator, absorber, condenserand generator shall be hydrostaticallytested at 1.5 times rated design pressure andheld for 1 hour.
3. All machine wiring shall undergo an insulationresistance test. The machine control panel andall electrical components shall also be functionallytested to verify continuity and properelectrical operation.
4. Final assembly inspection shall consist of verifyingthat all valves, controls, instrumentation,pumps, purge components and all othermachine components have been properlyinstalled on the machine.
5. Each unit shall be checked for overall appearanceand dimensional accuracy.
6. Final inspection shall be performed on eachunit to check that the nameplate data is correctand that all accessories are furnished asrequired.
1.03 DELIVERY, STORAGE, AND HANDLING
A. Unit shall be stored and handled in accordance withthe manufacturer's recommendations.
B. Unit shall be factory-charged with lithium bromidesolution if the machine is configured to ship in onepiece. For shipments of multiple pieces, charging oflithium bromide solution shall be performed at thejobsite in accordance with the manufacturer’s writteninstructions.
C. All units shall be shipped with 3 psig nitrogenpressure.
D. Chiller shall be shipped with nameplates indicatingname of manufacturer, model size, serial numberand all other pertinent machine data.
1.04 WARRANTY
Manufacturer shall guarantee the chiller against defects inmaterials or workmanship for a period of one year fromdate of initial operation or 18 months from date of shipment,whichever occurs first. Manufacturer shall providethe labor to repair or replace any part found to be defectivein material or workmanship within the warranty period.
Part 2 — Products
2.01 EQUIPMENT
A. General:
Absorption liquid chiller shall include evaporator,absorber, condenser, generator, solution heatexchanger, refrigerant/absorbent pumps, purgesystem, piping, wiring, controls and auxiliaries.Standard shipment of the machine shall be in onepiece. Initial charge of lithium bromide shall beshipped inside the machine for all single-piece shipments.For multiple piece shipments, initial chargeof lithium bromide shall be shipped separately forcharging at the jobsite. Generator shall be designedfor operation on low pressure steam as specified onthe equipment schedule. A rupture disk shall be providedas standard on all machines.
B. Operating Characteristics:
1. Chiller operation shall be characteristic of asingle-effect absorption cycle. The weaksolution pumped from the absorber to thegenerator shall initially pass through a solutionheat exchanger to improve operating efficiencyby preheating the weak solution on the tubeside with the strong solution returning from thegenerator on the shellside.
2. Unit shall be capable of continuous operationfrom 100 to 10% capacity, with enteringcondenser water temperatures as low as 64 Fwithout the need for a cooling tower bypassvalve. Thermostat on/off control of the coolingtower fan is recommended when cooling watertemperature falls below 64 F.
C. Heat Exchangers:
1. All heat exchangers shall be of shell and tubeconstruction with shells, tube sheets, tubesupport sheets and waterboxes fabricated ofcarbon steel. All heat exchangers shall incorporatestraight tubes. Tube material shall becopper for all heat exchangers except for thosetubes in contact with the externally suppliedsteam, which shall be 90/10 cupronickel. Theevaporator, absorber, condenser and generatortubes shall be rolled into grooved tubesheetsand expanded into tube support sheets, andshall be individually replaceable.
2. The evaporator, absorber and condenser waterboxesshall be designed for 150 psig workingpressure. The absorber and condenser waterboxesshall be hinged to permit access toall tubes from either end. Nozzle-in-head(NIH) type waterboxes shall be supplied on theevaporator while the absorber-condenser waterboxesshall be marine type. Waterboxes shall beprovided with vent and drain connections.Epoxy painting of the waterboxes and tubesheets shall be provided for corrosion protection.ANSI 150 psig R.F. (raised face) flangesshall be furnished on all waterbox nozzleconnections.
3. The generator tube side shall be designed for15 psig working pressure for use with low pressuresteam.
4. A solution heat exchanger shall be an integralpart of the machine to increase cycle efficiencyby preheating the weak solution on its way tothe generator while pre-cooling the strong solutionreturning from the generator. To furtherimprove efficiency, a heat reclaimer shall alsobe furnished to pre-heat the weak solution withsteam condensate from the generator.
5. Dispersion trays shall evenly distribute refrigerantover the evaporator tubes and lithium bromideover the absorber tubes. These trays shallbe fabricated of stainless steel to ensure continuous,corrosion-free, high-efficiency operation.
D. Pump/Motors:
Refrigerant and absorbent pump/motor assembliesshall be of the self contained, leakproof, hermetictype, without an external seal water systemto minimize air leakage into the machine. Lubricationand cooling shall be accomplished by thefluid being pumped; auxiliary water piping for coolingand lubrication shall not be acceptable. Eachpump casing shall be welded into the piping atthe factory and shall be furnished with isolationvalves on the suction and discharge side. Each pumpshall include spring-loaded, wear-compensatingtapered carbon bearings to ensure long life and reliability.Pump/motor assemblies shall be designedfor 25,000 hours of normal operation betweeninspections.
E. Purge System:
An automatic purge system shall be furnished toprovide a continuous purging action whenever thechiller is in operation to assure long machine life andefficient performance. Noncondensables shall beremoved from the absorber by a liquid eductor,which shall use flow from the absorbent pump tocreate a suction. Noncondensables shall be storedexternal to the unit and shall be prevented from diffusingback into the machine when the unit is notoperating. A palladium cell shall be provided toautomatically vent hydrogen gas from the purgechamber to the atmosphere. It shall be continuouslyenergized, even during machine shutdown. Furtherevacuation of the external storage chamber shall beaccomplished with a factory-mounted purge pump,piped and wired to the machine. The need to operatethe purge pump shall be indicated on the frontof the control panel.
F. Controls, Safeties and Diagnostics:
1. Controls:
a. The chiller shall be provided with a factory-installedand factory-wired microprocessorcontrol system with modular componentconstruction. The controls shall be of thePID type and shall continuously monitorthe operation of the chiller and performself-diagnostic checks to ensure that allcontrol limits are satisfied and maintained.The system shall include a control center,power supply, temperature sensors, pressuresensors and all necessary auxiliarydevices required for safe and proper chilleroperation housed in a NEMA-1 enclosurewith a hinged, lockable door. Control powershall be 24-1-60.
The chiller control system shall have the abilityto interface and communicate with abuilding management system with additionalhardware.
The control system shall include a 7-segmentlight-emitting diode (LED) display screenwith function keys, emergency stop buttonand indication lamps. The microprocessorshall be configurable to display either Englishor metric units.
b. The control panel display screen shall allowan operator to easily set and display theoperating mode and configurable settings ofthe machine. The display shall indicatepower on, chiller run status, safety circuitand alarm status, remote/local operation,standby mode and dilution cycle operation.Data input and machine settings shall bedone via a data select key and shall allowscrolling through the individual chillerparameter settings.
c. Monitoring the operation of the chiller shallbe done on a continuous basis. The displayshall indicate all pertinent system operatingparameters and alarms, as necessary, includingthe following:
1) Chiller operating hours.
2) Chilled water inlet temperature.
3) Chilled water outlet temperature.
4) Chilled water temperature set point.
5) Cooling water inlet temperature.
6) Condenser temperature.
7) Generator temperature.
8) Steam condensate temperature.
9) Absorbent pump start counter and operatinghours.
10) Refrigerant pump start counter andoperating hours.
11) Purge pump start counter and operatinghours.
12) Chiller start counter.
13) Purge tank pressure.
d. Capacity control shall be by means of electronicallymodulating the accessory steamcontrol valve to maintain the temperature ofthe chilled water. Load modulation shall befrom 100% to 10% of machine full loadunder normal ARI conditions. The steamcontrol valve shall be positioned by a PIDcontrol algorithm to ensure precise controlof desired chilled water temperature withouthunting or overshooting the set point.
e. The microprocessor control system shallinclude a programmed sequence to ensuremachine readiness prior to machine start-up.The microprocessor shall automaticallyenable and interlock the chilled water pump,cooling water pump and cooling tower fansupon chiller activation.
f. Upon request to start the chiller, the controlsystem shall start the chilled water pump andverify chilled water flow. The controller shallthen start the cooling water pump and verifyinterlock signal, before starting tower fan(s),absorbent pump and refrigerant pump.
g. The control system shall automatically senseimpending abnormalities in the absorptionoperating cycle and take the followingactions to either self-correct and/or limit themachine from approaching cycle crystallizationline:
1) Close steam control valve for a setperiod.
2) Stop the operation of the machine afterperforming a dilution cycle if the solutionconcentration is still over the pre-setlevel.
h. The rate at which the steam control valve isopened shall be precisely controlled to limitstart-up steam demand.
i. The control system shall automatically cyclethe refrigerant pump whenever the leavingchilled water temperature falls below thedesired set point. The chilled water pumpshall remain on and when the leaving chilledwater temperature rises above the set point,the refrigerant pump shall automaticallyrestart.
j. The control center shall allow reset of thechiller water temperature set point basedupon any one of the following criteria:
1) Chilled water reset based on an external4 to 20 mA signal.
2) Chilled water reset based on coolingwater inlet temperature.
k. When the stop button is pressed or remotecontacts open the control center shall immediatelydrive the steam control valve to theclosed position and initiate the normal shutdownsequence including dilution cycle. Thedisplay shall indicate that the machine is inthe dilution cycle.
2. Safeties:
a. Unit shall automatically shut down when anyof the following conditions occur. In addition,the chiller goes into alarm mode andindicates the reason for the shutdown on thechiller data display.
1) Absorbent pump motor overload.
2) Refrigerant pump motor overload.
3)Purge pump motor overload.
4) Low chilled water temperature.
5) Low cooling water temperature.
6) Generator high temperature.
7) Generator high pressure.
8) Loss of chilled water flow.
9) (Optional) loss of cooling water flow.
10) Loss of chilled water pump interlock.
11) Loss of cooling water pump interlock.
12) High solution concentration.
b. The control system shall detect conditionsthat approach protective limits and take self-corrective action prior to an alarm occurring. The system shall automatically reduce chiller capacity when any of the followingparameters are outside their normal operatingrange:
1) Low cooling water inlet temperature.
2) High cooling water inlet temperature.
3) High solution concentration.
3. Diagnostics and Service:
a. The chiller control system shall execute aseries of self-diagnostic checks wheneverpower is first turned on to determine if temperaturesare within pre-start limits, therebyallowing start-up to proceed. If any of thelimits are exceeded, an alert message will bedisplayed, informing the operator of thecause of the pre-start alert.
b. The control system shall provide an alarmdisplay on the front of the panel for any sensorthat has failed. These sensors include:
1) Chilled water inlet temperature.
2) Chilled water outlet temperature.
3) Cooling water inlet temperature.
4) Cooling water outlet temperature.
5) Cooling water intermediate temperature.
6) Condenser temperature.
7) Refrigerant temperature.
8) Diluted solution temperature.
9) Generator temperature.
10) Purge tank pressure.
11) Steam condensate temperature.
c. The chiller controls shall display maintenancemessages and alarms when efficientoperation of the chiller is in jeopardy orwhen immediate attention is necessary.When operating conditions are predicted tobe problematic, the following messages shallbe displayed on the panel:
1) Purge tank high pressure.
2) Cooling water tubes excessive fouling.
3) Cooling water high temperature.
4) Power failure.
4. Building Control System Interface:
The chiller control system shall have the abilityto interface and communicate directly to thebuilding control system with additional field-installedhardware and software.
G. Electrical Requirements:
1. Power supply to the unit shall be 3 ph, 60 Hzwith voltages of 208 or 460 as specified on theequipment schedule. A control transformershall provide 24-volt single-phase secondary power for the control panel.
2. Contractor/owner shall supply and installthe electrical power line and all auxiliary electricalprotection devices per local code requirementsand as indicated necessary by the chiller manufacturer.
3. Contractor/owner shall supply and install electricalwiring and devices required to interfacethe chiller controls with the building controls system if applicable.
H. Piping Requirements:
1. Piping and instrumentation for the chilledwater, cooling water, steam and condensatepiping shall be supplied and installed by the contractor/owner.
2. Absorber-condenser crossover piping shall be furnished by the chiller manufacturer.
3. Cooling water flow switch shall be supplied byeither the chiller manufacturer or the contractor/ owner.
4. Piping from the rupture disk shall be providedand installed by the contractor/owner andpiped in accordance with the chiller manufacturer’swritten instructions and any local jurisdictional requirements.
I. Thermal Insulation:
Insulation of the evaporator, refrigerant pump,sump, piping and chilled water headers, in additionto any hot surfaces shall be field supplied andinstalled on the machine. Chiller manufacturer shallrecommend the material and specify surface area to be insulated.
J. Sound Level:
The overall sound pressure level of the chiller shallnot exceed 80 dbA when measured per ARI Standard 575-1994.
K. Start-up:
1. Unit manufacturer shall provide a factory-trainedservice representative, employed by thechiller manufacturer, to perform and/or supervisechiller pressure test (when required), chargechiller with refrigerant (water) and lithiumbromide solution, place unit into operation, andcalibrate all controls in accordance with themanufacturer’s written start-up, operating and maintenance instructions.
2. After unit start-up has been performed, the samefactory representative shall be available for aperiod of instruction not to exceed 4 hours toinstruct the owner's personnel in the proper start-up, operating and maintenance procedures.
3. Manufacturer shall provide the following documentation and literature:
a. Installation Instructions.
b. Start-Up, Operating and Maintenance Instructions.
c. Dimensional Drawing.
d. Foundation Drawing.
e. Field Wiring Diagram.
L. Options and Accessories:
1. Marine Waterboxes:
Marine waterboxes with removable covers tofacilitate tube cleaning and maintenance shallbe furnished when specified on the equipment schedule.
2. High-Pressure Waterboxes:
Waterboxes rated for 300 psig working pressurewith removable covers shall be furnished when specified on the equipment schedule.
3. Special Tubing:
Tubing of non-standard materials, geometry orwall thickness shall be provided when specified on the equipment schedule.
4. Shipping Configuration:
Chiller shall ship either fully assembled or inmultiple pieces as specified on the equipment schedule.
5. Victaulic Nozzle Connections:
Victaulic grooves shall be provided on allwaterbox nozzle connections when specified on the equipment schedule.
6. Cooling Water Flow Switch:
Cooling water flow switch, rated for either150 psig or 300 psig, shall be factory supplied when specified on the equipment schedule.
7. Isolation Package:
A vibration isolation package consisting ofneoprene isolation pads shall be furnished when specified on the equipment schedule.
8. Steam Control Valve (Electronic or Pneumatic):
An accessory steam control valve shall be provided when specified on the equipment schedule.
9. Thermometer Set:
A package of 5 adjustable angle thermometersshall be factory-supplied for field installationwhen specified on the equipment schedule.Each shall have a 9 in. scale with a workingrange of 0° F to 120 F and shall be equipped with a ¾-in. NPT brass well.