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Centrifugal chillers McQuay WSC, WDC User manual

1. Efficiency Hotel in Atlanta Hospital in Shanghai China 40 Z 2 E 3 Z L ES G se 10 20 30 40 50 60 70 80 90 100 10 20 30 40 50 60 70 80 90 100 Percent of Full Load Percent of Full Load School In St Louis Office in Denver 40 r 5 5 E e o et 10 20 30 40 50 60 70 80 90 100 10 20 30 40 50 60 70 80 90 100 Percent of Full Load Percent of Full Load Note Building part load data directly from a major manufacturer s load and energy program Most buildings operate at their full design cooling load for only a few hours a year yes hours In fact some buildings schools for example may never run at full design load Except for some electrical demand considerations why be concerned about a chiller s full load kW ton COP at all The real question should be what does it cost to run the chiller in my building at my loads and my power costs The answer to this question is in the part load efficiency of the chiller and no chiller can do as well as the McQuay Dual Centrifugal These chillers excel when it comes to operating efficiency in the five percent to sixty percent capacity range where 70 percent of the annual operating occur in most buildings The building part load curves shown above are from detailed energy studies performed on various building types See page 16 for a comprehensive discussion of dual compressor advantages Product Manual PM WSC WDC 2 Variable Frequency Drive
2. 22 SOUMG HP 25 Unit Selection TT 27 Chiller Identification 29 Physical Data and Weights 30 A seesdeseunesvepsedergese 30 Condenser o eene dia 3l COIpresSSOF ui eene rnnt entere nr 32 Relief Valve zik balck ee a 32 Refrigerant Recovery Units DIMENSIONS eec AA 34 Chill eh rr P rot OS 34 Marine Water Boxes WSC eee 44 Marine Water Boxes WDC 45 Weights Electrical Data 48 Control POWer iieo ione aT EZZ d 53 Motor Starters cooooocccnonocnncnononnncnnnnnnnnnnnns 54 Variable Frequency Drives 57 Application Considerations 61 OIDCOOlerSus ce eoe eem eio 63 Options and Accessories 66 Specificauons Jute Re 68 Cover picture Model WDC 126 2300 ton dual compressor chiller UNO Our facility is ISO Certified Initial Issue September 1998 McQuay is registered trademarks of McQuay International 21996 McQuay International Data and illustrations cover McQuay International products at the time of publication and we reserve the right to make changes in design and construction at anytime without notice Product Manual PM WSC WDC 2 Introduction THE DISTINCTION SERIES As a result of extensive research and development efforts on both heat transfer and compressor components McQuay will enter the 21 century with a new generation of centrifugal chillers S
3. Product Manual PM WSCWDC 2 Group Chiller Date October 2002 Supersedes PM WSCWDC 1 Centrifugal Compressor Water Chillers THE DISTINCTION SERIES Model WDC Dual Compressor 160 to 2700 Tons 560 to 9500 kW Model WSC Single Compressor 80 to 1300 Tons 280 to 4550 kW HFC 134a The Global Refrigerant of Choice McQuav O 2001 McQuay International Air Conditioning Table of Contents Introduction iie e d 3 Customer Benefits 4 Wide Choice of Capacities and Efficiencies 4 Dual Compressor Design sss 5 Variable Frequency Drive s HECFz13432 11 eet etd 6 Compressor Design eee 8 Compact Design eee 12 Heat Exchangets 2 da 13 Lubrication System eee 13 AAA oos 14 P impdOWDnD eerte E IN TN 14 Thermal Expansion Valves ss 14 Factory Performance Test McQuayService Startup sess WDC Design Features Industry Leading Efficiency The Redundancy Feature sess Part Load Efficiency sess Lower Installed Costs esses Bolt Together Construction WDC Chiller Controls sess Control Features esses 20 BACdrop Panel eee 21 Building Management Systems 22 Multiple Machine Control
4. Mas N __ Locked Rotor Amps Power Factor O Max kW 505 4778 3737 91 90 89 87 9 Makw Locked Rotor Amps T T T T Power Factor Maxkw J T T T MexkW o 563 5 564 563 563 567 567 567 Power Factor O Max kW 91 92 91 91 91 90 90 90 Maxw Tori L Locked Rotor Amps T T T T T T T T T TJ T J3 Power Factor Maxkw J T T T T T BR Maxxw o To o f s2 660 660 660 664 665 664 Locked Rotor Amps 5692 4572 4790 5008 3830 976 658 564 Power Factor EMaxkw J 2 2 92 e 92 9 91 20 Maxxw 777 777 775 778 773 J __ Locked Rotor Amps J 6612 5618 5885 6155 4811 Power Factor MaxkW T Jf 92 02 91 2f Me EE q S T ES ST T T ed eee Locked Rotor Amps J Power Factor O MaxkW T Nan MN Locked Rotor Amps Power Factor MaxkW J pe ERES po LL 466 3665 91 91 90 89 91 90 90 90 X L LL Lse so sof L oy Lre se sdej Dr e T J RO aereo 1 3 505 505 505 505 T 3737 3914 91 90 3914 4092 8131 T MaxkW 87 88 8
5. E E Des d aie 4 E S VALVE STOP T COOLING TOWER WATER VALVE E SUPPLY STRAINER COOLING TOWER MAKEUP DISCHARGE ABOVE i HIGHEST POSSIBLE MAX 40 MESH WATER LEVEL DRAIN VALVE OR PLUG OPEN DRAIN Machine Room Ventilation In the market today centrifugal chillers are available with either hermetic or open type motors Hermetic motors are cooled with refrigerant and dissipate their heat through the cooling tower On the other hand open motors circulate equipment room air across themselves for cooling and reject the heat to the equipment room McQuay chillers have hermetic motors and DO NOT require additional ventilation For chillers with air cooled motors good engineering practice dictates that the motor heat be removed to prevent high equipment room temperatures In many applications this requires a large volume of ventilation air or mechanical cooling to properly remove this motor heat EXAMPLE 1000 tons x 0 6 kW Ton x 0 04 motor heat loss x 0 284 Tons kW 7 tons 24 kW cooling The energy and installation costs of ventilation or mechanical cooling equipment must be considered when evaluating various chillers For a fair comparison the kW used for the ventilation fans or if mechanical cooling is required the additional cooling and fan energy must be added to the open motor compressor energy when comparing hermetic drives Additionally significant costs occur for the purchase installation and maintenance o
6. coo x cone x cmo co X co x ce co X co Care x cmo cao Caio X cmo Cao Product Manual PM WSC WDC 2 31 32 Compressor Table 3 Compressor Weights Weight Ib kg gt 870 390 3200 1440 3200 1440 3200 1440 6000 2700 6000 2700 Relief Valves Vessel Relief Valves Relief valve connection sizes are 1 in FPT and are in the quantity shown in Table 1 and Table 2 Relief valves must be piped to the outside of the building in accordance with ANSI ASHRAE 15 Twin relief valves mounted on a transfer valve are used on the condenser so that one relief valve can be shut off and removed leaving the other in operation Only one of two is in operation at any time Where 4 valves are shown they consist of two valves mounted on two transfer valves Only two relief valves of the four are active at any time Vent piping is sized for only one valve of the set since only one can be in operation at a time In no case would a combination of evaporator and condenser sizes require more refrigerant than the pumpdown capacity of the condenser Condenser pumpdown capacities are based upon ANSI ASHRAE Standard 15 1992 recommendations of 90 full at 90 F 32 C To convert values to the older ARI standard multiply pumpdown capacity by 0 888 Relief Valve Pipe Sizing Relief valve pipe sizing is based on the discharge capacity for the given evapora
7. 7085 8211 129 11 9 243 918 8679 8937 4422 2006 264 24 5 12215 5536 481 1819 827 1297 556 2106 302 281 X 661 2503 17190 7791 ap RRR charge is approximate since the actual charge will depend on other variables Actual charge will be shown on the unit name 2 Water capacity is based on standard tube configuration and standard heads 3 The evaporator charge includes the maximum condenser charge available with that evaporator and is therefore the maximum charge for a total unit with the evaporator Actual charge for a specific selection can vary with tube count and can be obtained from the McQuay Selection Program The program will not allow a selection where the unit charge exceeds the condenser pumpdown capacity Product Manual PM WSC WDC 2 Condenser With positive pressure systems the pressure variance with temperature is always predictable and the vessel design and relief protection are based upon pure refrigerant characteristics HCFC 123 systems are not ASME designed inspected and stamped HFC 134a requires ASME vessel design inspection and testing and uses spring loaded pressure relief valves Negative pressure units use rupture disks When an over pressure condition occurs the rupture disk is permanently destroyed Spring loaded relief valves purge only that refrigerant required to reduce system pressure to a safe level and then close Refrigerant side design pressure is 200 psi 1380 kPa on WSC units and 225 p
8. STARTER OPTIONAL STARTER OPTIONAL FOOTPRINT VESSEL CODE OVERALL LENGTH JoyeraLL OVERALL ewe 183 HEIGHT WIDTH W O CENTER OF GRAVITY FOOTPRINT EVAP EVAP COND PASS PASS BOTH ENDS STARTER 2 2 A A A Lx Ty oz p E rF o PASS Pass 1 17 B C 218 214 218 9 36 199 196 58 E2416 C2416 5544 5426 5544 2032 1470 2318 911 425 5048 4972 1470 80 58 214 218 80 58 91 35 17 199 196 58 261 5426 da sre 214 218 80 58 91 36 16 199 196 58 E2816 02416 cas 6429 ious sre 214 218 80 58 92 35 17 199 196 58 E2616 caste 5426 899 5048 4972 221 214 221 90 64 95 40 21 199 196 64 E3016 aote 5623 5445 2410 1029 537 5048 1619 Note See notes on page 34 Product Manual PM WSC WDC 2 39 Figure 15 WDC 079 600 to 700 tons STARTER EVAPORATOR STARTER OPTIONAL OPTIONAL CONDENSER FOOTPRINT VESSEL CODE OVERALL LENGTH over OVERALL 183 2 HEAD CONN eigar WIDTH W O CENTER OF GRAVITY FOOTPRINT EVAP COND EVAP COND PASS PASS BOTH ENDS STARTER 2 2 m AAA wo Bp Pass 214 221 94 57 93 44 19 199 196 57 49 soe csore co ado 6020 224 218 224 100 71 94 45 32 199 196 57 49 coo ose som 224 218 224 106 74 94 48 32 199 196 74 66 caste css eso Note See notes on page 34 Product Manual PM WSC WDC 2 Figure 16 WDC 087 700 to 1200 tons STARTER OPTI
9. 1 4 QUALITY ASSURANCE A B Es Qualifications Equipment manufacturer must specialize in the manufacture of the products specified and have five years experience with the equipment and refrigerant offered Regulatory Requirements Comply with the codes and standards in Section 1 2 Chiller manufacturer plant shall be ISO Registered 1 5 DELIVERY AND HANDLING A Chillers shall be delivered to the job site completely assembled and charged with refrigerant and oil Comply with the manufacturer s instructions for rigging and transporting units Leave protective covers in place until installation Product Manual PM WSC WDC 2 1 6 WARRANTY The refrigeration equipment manufacturer s warranty shall be for a period of one Or two Or five years from date of equipment start up or 18 months from shipment whichever occurs first The warranty shall include parts and labor costs for the repair or replacement of defects in material or workmanship 1 7 MAINTENANCE Chiller maintenance shall be the responsibility of the owner with the following exceptions A B The manufacturer shall provide the first year scheduled oil and filter change if required The manufacturer shall provide first year purge unit maintenance if required PART 2 PRODUCTS 2 1 ACCEPTABLE MANUFACTURERS A B McQuay International Approved Equal 2 2 UNIT DESCRIPTION Provide and install as shown on the plans a factory assemb
10. 1 EE Gea 2 2 E y I 1 FACTORY MOUNTED EVAPORATOR 1 STARTER OPTIONAL i 1 I H d E a E CONDENSER A 175 175 4445 175 175 4445 175 181 4597 181 167 4242 168 4267 168 4267 170 4318 170 4318 175 4445 OVERALL LENGTH PASS PASS PA J A A B c x 65 1549 EARS 4445 2515 1880 1727 1194 686 4445 2515 2032 1727 1168 787 4445 2515 2184 1753 1143 889 92 98 HEAD CONN BOTH ENDS 175 4445 175 102 4445 2591 4597 2692 181 4597 Product Manual PM WSC WDC 2 OVERALL HEIGHT 97 2464 106 2692 61 104 2642 70 1778 LY 2 47 46 1168 Z 21 553 EEES 2337 1753 1143 940 En 2489 1753 1168 1067 46 1168 D 148 OVERALL WIDTH W O CENTER OF GRAVITY FOOTPRINT STARTER 145 9683 1549 1880 2032 86 2337 2489 104 2642 53 1346 66 1676 N N 1829 1981 2134 2438 N A N N o oo 2 o A N m o o e o CONNECTIONS EVAP COND 2 2 PASS PASS 10 12 12 14 14 18 Az 18 For optional unit mounted starter starter is shipped separate for fiel
11. 4 If compressors are not equipped with guide vanes for each stage and movable discharge diffusers then furnish hot gas bypass and select chillers at 5 lower kW ton than specified to compensate for bypass inefficiency at low loads Lubrication System Each compressor shall have an independent lubrication system to provide lubrication to all parts requiring oil Provide a heater in the oil sump to maintain oil at sufficient temperature to minimize affinity of refrigerant and a thermostatically controlled water cooled oil cooler Coolers located inside the evaporator or condenser are not acceptable due to inaccessibility A positive displacement submerged oil pump shall be powered through the unit control transformer Refrigerant Evaporator and Condenser 1 Evaporator and condenser shall be of the shell and tube type designed constructed tested and stamped according to the requirements of the ASME Code Section VIII Regardless of the operating pressure the refrigerant side of each vessel will bear the Product Manual PM WSC WDC 2 ASME stamp indicating compliance with the code and indicating a test pressure of 1 3 times the working pressure but not less than 100 psig Provide intermediate tube supports at a maximum of 24 inch spacing 2 Tubes shall be enhanced for maximum heat transfer rolled into steel tube sheets and sealed with Locktite or equal sealer The tubes shall be individually replaceable and secured to the intermediate suppor
12. Efficiency Variable frequency drive is a technology that has been used for decades to control motor speed on a wide variety of motor drive applications When applied to centrifugal compressor motors significant gains in compressor part load performance can be realized The improvement in efficiency and reduction of annual energy cost is maximized when a there are long periods of part load operation combined with low compressor lift lower condenser water temperatures This operating scenario will offset the small VFD full load power penalty Combining the attributes of VFD drives and the extremely efficient McQuay WDC Dual Centrifugal Chiller produces the industry s most efficient chiller based on the all important IPLV value See IPLV NPLV Defined on page 28 for details on the ARI IPLV efficiency rating Starting Inrush The use of a VFD on centrifugal chillers also provides an excellent method of reducing motor starting inrush even better than solid state starters Starting current can be closely controlled since both the frequency and voltage regulated This can be an important benefit to a building s electrical distribution system Sound The sound level of centrifugal compressors is largely dependent on the impeller tip speed By reducing compressor speed the sound level is also reduced HFC 134a Helping To Keep The Ozone Whole McQuay Positive Pressure Design No Purge No Vacuum Prevention System No Contaminants HFC 134a operate
13. Low oil differential pressure h High motor temperature low motor current 1 Surge high suction superheat j Starter fault no starter transition k Vanes open during start sequence D Sensor failure specific to sensor Controller shall hold leaving chilled water temperature to within 0 2 F without hunting droop or overshooting Controller shall be able to limit motor amps from 30 to 100 of RLA based on a keypad entry or by a remote 4 20mA DC signal Product Manual PM WSC WDC 2 The controller shall be able to reset chilled water temperature by controlling return chilled water temperature or from a remote 4 20 mA DC signal The amount of reset shall be adjustable Programmable load ramping shall be provided to prevent the unit from operating at full load during pulldown if desired A time clock shall be incorporated to allow daily timed starts and stops and to allow for holidays and weekends The control system shall have automatic restart after a power failure and not require a battery backup for memory continuity A battery shall be provided for the time clock only The controller shall be capable of starting and stopping chilled and condenser water pumps It shall also be capable of four step control of cooling tower fans and provide an analog output for a tower bypass valve The microprocessor shall be capable of communicating to other units or a PC using a twisted pair communication interface of RS 232 100 feet or RS 42
14. Hz units are run tested at 60 Hz to their motor maximum power Optional Witness Test A McQuay engineer oversees the testing in the presence of the customer or their designate and translates the test data onto an easy to read spreadsheet The tests can be run at ARI load points between 10 and 100 It takes two to three hours of test time per load point specified Tests are run to ARI tolerances of capacity and power 50 Hz units are run tested at 60 Hz to their motor maximum power McQuayService Startup All McQuay centrifugal chillers are commissioned by McQuayService personnel or by authorized McQuay startup technicians This procedure assures proper starting and checkout procedures and results in a trouble free initial startup Product Manual PM WSC WDC 2 15 16 WDC Design Features One WDC Dual Compressor Chiller Two Single Compressor Chillers 17 is greater than 2 when it means Lower equipment costs than 2 separate units Lower installation cost than 2 separate units Lower annual operating cost than either 1 large or 2 small units Less equipment room space required than for 2 separate units Capacity reduction to 5 of design cooling tons Standby redundancy for 80 of the cooling season Industry Leading Efficiency When coupled with McQuay s Variable Frequency Drive the extremely efficient Dual Compressor Chillers become the most efficient chillers available in the market place IPLVs in the low 0 3s Do not be fool
15. STARTER DELTA P DELTAP He a1 FLOW ORFLOW OR n a EVAP COND 6 6 20 o 22 COOLING TOWER NOTE 2 FIRST STAGE STARTER LOAD NOTE SEE COMPRESS R M T pil m4 16 Te MOTOR STARTER calls en N 35 o qu a de CONDENSER NOTE i 9 WATER OTE 2 2AVAC E PUMP 164 REMOTE STARTERS FOR DC VOLTAGE AND 4 20 MA o ON OFF CONNECTIONS SEE NOTE 3 i65 NOTE 5 e a 1 FOR DETAILS OF CONTROL REFER TO 3 UNIT CONTROL SCHEMATIC 071853301 EM ALARM RELAY D NOTE 4 FIELD SUPPLIED ITEM oa z3 NOTE 13 SEE OIL COOLER T2 SOLENOID OPTION i 70 NOTE 7 52 Product Manual PM WSC WDC 2 Notes 1 10 11 12 Compressor motor starters or VFDs are either factory mounted and wired or shipped separate for field wiring If provided by others starters must comply with McQuay specification 3594999 All line and load side power conductors must be copper VFDs can only be supplied by McQuay If starters or VFDs are free standing then field wiring between the starter and the control panel is required Minimum wire size for 115 VAC is 12GA for maximum length of 50 feet If greater than 50 feet refer to McQuay for recommended wire size minimum Wire size for 24 VAC is 18 GA All wiring to be installed as NEC class 1 wiring system All 24 VAC wiring must run in separate conduit from 115 VAC wiring Main power wiring between starter and motor terminal is factory installed when units are supplied with mounted sta
16. ae p St 063 to 087 6754 5170 87 88 1 Locked Rotor Amps 063 to 087 wer Factor O Max kW MekW UU Max kW 100 to 126 Locked Rotor Amps wer Factor O Max kW OO e Locked Rotor Amps wer Factor O Max kW MakW i Bio Max kW 063 to 087 Locked Rotor Amps wer Factor O Max kW Ro e Locked Rotor Amps Po 424 sto Po ar 7 O mw 7 S Max kW E Po E Po 48r 7 Po Po Po Po Po Po Po Po 467 470 468 468 3880 92 9 545 547 545 545 m 100 to 126 100 fo 126 10010 128 91 915 100 to 126 NO 1000 100 to 128 N1 1080 100 10126 N2 1200 100 to 1261 92 9 90 2 n 90 lr a eres E al o o x A E A ees 6059 9 92 9 2 9 2 n 90 A DL A pp HT E 89 88 88 89 88 8 6930 6658 5565 88 8 4 1 1 1 8 88 so 89 6898 6003 so se 90 90 00 Product Manual PM WSC WDC 2 51 Field Wiring Centrifugal compressor motors have been redesigned to increase efficiencies well into the 90 range This design change is particularly important since it represents a motor characteristic that directly impacts the system s watt hour meter In addition the motor efficiency unlike power factor is a design characteristic that cannot be improved on the job Wiring and Conduit Wire sizes should comply with local and state electrical codes Where total amperes require larger conductors than a s
17. also be reduced by slowing down the compressor speed and reducing the impeller tip speed providing sufficient tip speed is retained to meet the chiller s discharge pressure requirements This method is more efficient than guide vanes by themselves In actual practice a combination of the two techniques is used The microprocessor slows the compressor as much as possible considering the need for speed to make the required compressor lift Guide vanes take over to make up the difference This methodology provides the optimum efficiency under any circumstances VFD for Reliability Variable Frequency Drives also provide the soft start attributes normally associated with solid state starters In fact VFDs starting characteristics are superior since the starting inrush matches or only slightly exceeds the motor RLA The compressor motor starts with reduced starting current and torque meaning less stress as compared to conventional reduced voltage starters This translates to longer life and greater reliability VFDs have fewer contactors transformers overload relays and less wiring Fewer components mean less maintenance and improved reliability VFD for Sound Reduction During periods of reduced speed operation the already low sound levels of McQuay chillers will be further reduced as the impeller tip speed slows down Typically the full load sound level sound pressure in dBA as perceived by the human ear is reduced to less than 50 a
18. by chlorine the first C in HCFC 123 HFC 134a contains no chlorine and has a zero ODP and zero negative effect on the ozone layer e GWP Global Warming Potential measures the contribution of a substance to the greenhouse gas effect which causes global warming This is a pound to pound comparison discounting the application of the substance and any other effects caused by its use The numbers relative to CO for a 100 year integration time horizon are HCFC 123 90 HFC 134a 1300 HCFC 22 1500 Manufacturers utilizing HCFC 123 would have you believe that GWP is the primary and important measurement of global warming potential of a refrigerant This is untrue as is explained in the following description of Total Equivalent Warming Potential Product Manual PM WSC WDC 2 7 e TEWI Total Equivalent Warming Impact is a combination of the refrigerant GWP unit refrigerant emissions rate and the refrigeration Components of TEWI system s energy efficiency Science has agreed that a systems approach is necessary to evaluate the real effect of a substance on global warming This is TEWI In a chiller the contribution of the GWP 2 GWP is insignificant when compared to the effect of a unit s power needs translated to power plant CO emissions There is no meaningful difference between the TEWI of HFC 134a HCFC 22 or HCFC 123 The percentages shown on the right will vary slightly depending on unit refrigerant loss and on the efficiency of local p
19. control panels 11 Each starter shall be equipped with a line to 115 VAC control transformer fused in both the primary and secondary to supply power to the control panels oil heaters and oil pumps 12 Each starter shall include the following protective devices a Phase failure and reversal protection OR E Variable Frequency Drive 1 The chiller shall be equipped with a Variable Frequency Drive VFD to automatically regulate compressor speed in response to cooling load and compressor pressure lift The chiller control shall coordinate compressor speed and guide vane position to optimize chiller efficiency 2 A digital regulator shall provide V Hz control 3 The VFD shall have 110 continuous overload of continuous amp rating with no time limit PWM pulse width modulated output IGBT insulated gate bipolar transistors power technology full power rating at 2kHz DC bus inductor choke and wireless construction 4 Units 240 amps and below shall be air cooled units above 241 amps shall be water cooled All heat producing devices shall be contained in a single heatsink with single inlet and out connections for the connection of chilled water When factory mounted on the chiller package the water connections shall be piped and leak tested at the factory F CONTROL PANEL A microprocessor based control panel shall be fully wired and factory mounted on the chiller and have the following features Product Manual PM WSC WDC
20. input output signals for certain functions such as e Enable run input e Alarm signal output e 4 20ma or 0 5 VDC input for reset and load limiting e Pump and tower fan control e Analog output for variable speed fan or tower bypass 3 Remote monitoring by PC hard wired or via modem local control still in effect 4 Interfaced with Building Management System open protocol with full read and write capability PC Communications Not only can you operate MicroTech from the keypad display or via interconnection to the BMS but an optional software package lets you control it from any PC with a MS Windows 3 1 or above operating system Communicating with the MicroTech is accomplished using a single twisted pair RS 232 or RS 422 485 communications protocol Operators can monitor chiller information remotely on a personal computer By adding an optional modem interface all chiller operations can be controlled from a remote location through standard telephone lines The modem communication can be added to the unit control at any time MicroTech can also handle multiple unit installations with the optional Chiller System Control CSC panel This feature allows communications with the individual unit controllers to permit sophisticated sequencing control strategies In addition the System Controller can control and access all information available at the unit controllers The end result is optimum operating efficiency BACdrop Panel The McQuay MicroTech B
21. operating speed is reached the bypass contactor shall be energized removing the SCRs from the circuit during normal running The starter shall be capable of across the line starting in an emergency 6 The starter shall be coordinated with the chiller package s making certain all terminals are properly marked according to the chiller manufacturer s wiring diagrams T The starters shall be equipped with redundant motor control relays MCR with coils in parallel The relays interconnect the starters with the unit control panels and Product Manual PM WSC WDC 2 directly operate the main motor contactors The MCRs shall constitute the only means of energizing the motor contacts 8 The main contactors shall have a normally open and a normally closed auxiliary contact rated at 125VA pilot duty at 115 VAC An additional set of normally open contacts shall be provided for each MCR 9 There shall be electronic overloads in each phase set at 10796 of the rated load amps of each motor Overloads shall be manual reset and shall de energize the main contactors when the overcurrent occurs The overloads shall be adjustable and selected for mid range Overloads shall be adjusted for a locked rotor trip time of 8 seconds at full voltage and must trip in 60 seconds or less at reduced voltage 33 of delta LRA 10 Each starter shall have a current transformer and adjustable voltage dropping resistor s to supply a 5 0 VAC signal at full load to the unit
22. plates or subbases as called for on drawings Arrange the piping on each vessel to allow for dismantling the pipe to permit head removal and tube cleaning Furnish and install necessary auxiliary water piping for oil cooler Coordinate electrical installation with electrical contractor Coordinate controls with control contractor Provide all materiel required to ensure a fully operational and functional chiller Units shall be factory charged with the proper refrigerant and oil Factory Start Up Services Provide for as long a time as is necessary to ensure proper operation of the unit but in no case for less than two full working days During the period of start up the Start up Technician shall instruct the Owner s representative in proper care and operation of the unit Product Manual PM WSC WDC 2 SECTION 15XXX CENTRIFUGAL CHILLERS DUAL COMPRESSOR PART 1 GENERAL 1 1 SUMMARY Section includes design performance criteria refrigerants controls and installation requirements for water cooled centrifugal chillers 1 02REFERENCES Comply with the following codes and standards ARI 550 590 NEC ANSI ASHRAE 15 OSHA as adopted by the State ASME Section VIII 1 3 SUBMITTALS Submittals shall include the following A Dimensioned plan and elevation view Drawings including motor starter cabinet required clearances and location of all field piping and electrical connections B Summaries of all auxiliary utility requirem
23. slime buildup scaling or algae formation A water treatment service is recommended McQuay International is not responsible for damage or faulty operation from untreated or improperly treated water Product Manual PM WSC WDC 2 61 62 Condenser Water Temperature When ambient wet bulb temperature are lower than design the entering condenser water temperature may be allowed to fall Lower temperatures to a predetermined minimum improve chiller performance Normally McQuay centrifugal chillers will start with entering condenser water temperature as low as 55 F 42 8 C providing the chilled water temperature is lower Generally the chilled water temperature should be below the condenser water temperature for automatic starting During normal operation the minimum entering condenser water temperature assuming 3 gpm per ton flow is a function of the leaving chilled water temperature and load The table below gives the approximate minimum condenser water temperatures as a function of these variables These values may be lower in mild climates and low wet bulb areas Depending on local climatic conditions using the lowest possible entering condenser water temperature may be more costly in total system power consumed than the expected savings in chiller power would suggest due to the excessive fan power required To obtain 55 F 12 8 C entering condenser water 100 temperature with a tower selected to produce 85 F 9 29 4 C water te
24. system is not required Transfer of refrigerant charge shall be accomplished by either main compressor operation migration or gravity flow Isolation shall be accomplished with valves located at the inlet and exit of the condenser The main condenser shall be sized to contain the refrigerant charge at 90 F according to ANSI ASHRAE 15 Purge System HCFC 123 Chillers Only 1 The chiller manufacturer shall provide a separate high efficiency purge system that operates independently of the unit and can be operated while the unit is off The system shall consist of an air cooled condensing unit purge condensing tank pumpout compressor and control system 2 A dedicated condensing unit shall be provided with the purge system to provide a cooling source whether or not the chiller is running The condensing unit shall provide a low purge coil temperature to result in a maximum loss of 0 1 pounds of refrigerant per pound of purged air 3 The purge tank shall consist of a cooling coil filter drier water separation tube sight glass drain and air discharge port Air and water are separated from the refrigerant vapor and accumulated in the purge tank 4 The pumpout system shall consist of a small compressor and a restriction device located at the pumpout compressor suction connection 5 The purge unit shall be connected to a 100 reclaim device Vacuum Prevention System HCFC 123 Chillers Only Chiller manufacturer shall supply and install a va
25. upset the smooth voltage sinusoidal waveform 3 High frequency components of voltage distortion can interfere with signals transmitted on the ac line for some control systems The harmonics of concern are the 5 7 11 and 13 Even harmonics harmonics divisible by three and high magnitude harmonics are usually not a problem Current Harmonics An increase in reactive impedance in front of the VFD helps reduce the harmonic currents Reactive impedance can be added in the following ways 1 Mount the drive far from the source transformer 2 Add ine reactors 3 Use an isolation transformer Voltage Harmonics Voltage distortion is caused the flow of harmonic currents through a source impedance A reduction in source impedance to the point of common coupling PCC will result in a reduction in voltage harmonnics This may be done in the following ways 1 Keep the PCC as far from the drives close to the power source as possible 2 Increase the size decrease the impedance of the source tranformer 3 Increase the capacity decrease the impedance of the busway or cables from the source to the PCC 4 Make sure that added reactance is downstream closer to the VFD than the source from the PCC The IEEE 519 1991 Standard The Institute of Electrical and Electronics Engineers IEEE has developed a standard that defines acceptable limits of system current and voltage distortion A simple form is available from McQuay that
26. 111 2819 145 3683 145 3683 111 2819 111 2819 42 1067 1168 48 1219 48 1219 53 1646 56 1422 58 1473 G 34 864 w R 864 oo wo wo wo wo o o o BIR AIR AIR A 1270 PASS PASS 35 36 Figure 11 WSC 079 087 300 to 550 tons Do ll qu io U 1 FACTORY MOUNIEED EVAPORATOR i STARTER i OPTIONAL d E ee CONDENSER A VESSEL CODE A OVERALL LENGTH HEAD CONN ASS BOTH ENDS oven aoe HEIGHT STARTER 1 amp 3 EVAP COND PASS P A 7 6 6 134 29 134 169 64 169 140 132 140 140 132 140 4242 4445 175 167 175 140 133 140 175 168 175 175 168 E E 2 2 175 3012 C2612 4445 3 3 Note A 134 129 134 02209 169 164 169 134 129 134 02209 3277 169 4 169 1 1 1 A 175 4445 50 1270 C 1880 1143 1880 1143 1727 1981 1245 1295 1981 1245 1753 2108 1321 1295 2108 1321 1753 88 56 52 93 58 52 88 56 69 2362 1473 1778 2388 1880 1321 2388 1880 1778 2667 2032 1778 T E3612 C3612 combinat
27. 15 VAC An additional set of normally open contacts shall be provided for each MCR There shall be electronic overloads in each phase set at 107 of the rated load amps of each motor Overloads shall be manual reset and shall de energize the main contactors when the overcurrent occurs The overloads shall be adjustable and selected for mid range Overloads shall be adjusted for a locked rotor trip time of 8 seconds at full voltage and must trip in 60 seconds or less at reduced voltage 33 of delta LRA Each starter shall have a current transformer and adjustable voltage dropping resistor s to supply a 5 0 VAC signal at full load to the unit control panels Each starter shall be equipped with a line to 115 VAC control transformer fused in both the primary and secondary to supply power to the control panels oil heaters and oil pumps Each starter shall include the following protective devices a Phase failure and reversal protection b Stall protection OR Variable Frequency Drive 1 The chiller shall be equipped with a Variable Frequency Drive VFD to automatically regulate each compressor speed in response to cooling load and compressor pressure lift The chiller control shall coordinate compressor speed and guide vane position to optimize chiller efficiency Product Manual PM WSC WDC 2 A digital regulator shall provide V Hz control The VFD shall have 110 continuous overload of continuous amp rating with no time limit PWM pul
28. 2 485 5000 feet or with a 9600 baud modem 2 5 MISCELLANEOUS ITEMS A Pumpout System The unit shall be equipped with a pumpout system complete with a transfer pump condensing unit and storage vessel constructed according to ASME Code for Unfired Pressure Vessels and shall bear the National Board stamp If the design of the unit allows the charge to be transferred to and isolated in the main condenser then a pumpout system is not required Transfer of refrigerant charge shall be accomplished by either main compressor operation migration or gravity flow Isolation shall be accomplished with valves located at the inlet and outlet of the condenser The main condenser shall be sized to contain the refrigerant charge at 90 F according to ANSI ASHRAE 15 B Purge System HCFC 123 Chillers Only 1 Product Manual PM WSC WDC 2 The chiller manufacturer shall provide a separate high efficiency purge system that operates independently of the unit and can be operated while the unit is off The system shall consist of an air cooled condensing unit purge condensing tank pumpout compressor and control system A dedicated condensing unit shall be provided with the purge system to provide a cooling source whether or not the chiller is running The condensing unit shall provide a low purge coil temperature to result in a maximum loss of 0 1 pounds of refrigerant per pound of purged air The purge tank shall consist of a cooling coil fil
29. 2 73 74 The display shall have a minimum of 160 character liquid crystal display and be backlit with a light emitting diode Messages shall be in plain English Coded two or three character displays are not acceptable The following information shall be available on the display with simple entry on the keypad a Entering and leaving chilled and condenser water temperatures b Evaporator suction discharge condenser and liquid temperatures c Suction and discharge superheat d Liquid subcooling evaporator and condenser approach temperatures e Evaporator condenser and compressor lift pressures f Oil feed and sump temperatures g Oil pump discharge and oil differential pressure h Motor amps and amps as a percent of rated load amps 1 Hours of operation and number of starts time of last start and stop j Chilled water setpoint and reset temperature setpoint k Amp limit for manual and remote D History for last 8 faults with date and time plus critical sensor values m Unit status start up and shutdown sequence operational status The microprocessor shall either unload or shut down the compressor during an abnormal condition At a minimum the following safeties shall be incorporated in the control system a High and low discharge pressure b Low evaporator pressure c High discharge temperature d Chilled or condenser water pump failure e No evaporator or condenser water flow f High or low oil feed temperature g
30. 2209 13903 15569 7062 10959 4971 16769 12159 7606 5515 WSCO079 2212 2212 12294 5577 13494 6121 WSC079 2609 2209 11990 5439 13190 5983 WSC079 2612 2212 13548 6145 WSCO079 2609 2609 14160 6423 WSCO079 2612 2612 14752 6692 15952 7236 WSCO079 3012 2612 16301 7394 17501 7938 WSCO079 3012 3012 18061 8192 19261 8737 WSC079 WSC087 3612 3012 2609 2209 20807 9438 11990 5439 22007 9982 13190 5983 WSC087 2612 2212 13549 6146 14749 6690 WSC087 2609 2609 12960 5879 14160 6423 WSC087 2612 2612 14752 6692 15592 7073 WSC087 3009 2609 14246 6462 15446 7006 WSC087 3012 2612 16301 7394 17501 7938 WSC087 3009 3009 15644 7096 16844 7640 WSC087 3012 3012 18060 8192 19260 8736 WSC087 3609 3009 12960 5879 17929 8133 19129 8677 WSC087 3612 3012 20806 9438 14749 6690 22006 9982 WSC087 WSC100 3612 3612 3012 3012 19397 23799 10795 21339 9679 24999 11340 22539 10224 WSC100 3612 3012 21578 24045 10907 25245 11451 WSC100 3612 3612 23826 10807 2
31. 5045 12403 5626 13523 6134 WDC050 2216 2216 12874 5840 14485 6470 15274 6928 16885 7659 WDC050 2412 2212 12348 5601 13836 6276 14748 6690 16236 7365 WDC050 2416 2216 13957 6331 15820 7176 16357 7419 18220 8264 WDC050 2612 2212 12836 5822 14428 6544 15236 6911 16828 7633 WDC050 WDC063 2616 2216 2416 2416 14642 6642 18673 8470 16643 7549 20422 9263 17042 7730 21407 9710 14803 6715 19043 8638 23156 10503 WDC063 2416 2616 19365 8784 21294 9577 22099 10024 23848 10817 WDC063 2616 2416 19282 8746 21207 9639 22016 9986 23763 10779 WDC063 2616 2616 20025 9083 22091 9939 22759 10323 24646 11179 WDC063 WDC079 3016 3016 3016 3016 23545 10680 25131 11399 26405 11830 27671 12551 26279 11920 27531 12488 28815 30071 13070 13640 WDC079 3616 3016 28763 13047 32018 14523 31163 14135 34418 15612 WDC079 WDC087 3616 3616 3016 3016 32027 14527 26157 11865 36115 16382 28697 13017 28891 13105 38515 31431 17470 14257 WDC087 3616 3016 29789 13512 33044 14989 32523 14752 35778 15322 WDC087 WDC100 3616 3616 3616 3616 33053 14993 41816 18967 37141 16847 46513 21098 35
32. 7041 12266 28241 12810 WSC100 4212 3612 26457 12001 30260 13726 31460 14270 WSC100 4212 4212 29298 13290 34024 15433 35224 15978 WSC100 WSC126 4812 4212 3612 3012 32024 14526 21680 9834 37623 17066 25347 11497 WSC126 3612 3612 23928 10854 27143 12312 28343 12856 WSC126 4212 3612 26457 12001 30260 13726 31460 14270 WSC126 4212 4212 34024 15433 35224 15978 WSC126 4812 4212 32024 14526 37623 17066 38823 17610 WSC126 4812 4812 29298 13290 35016 15883 24147 10953 41817 18968 38823 17610 43017 19513 Product Manual PM WSC WDC 2 WDC050 Evaporator Condenser Size 1812 1612 Max Unit Weight Without Starter Max Unit Weight With Starter Shipping Ibs kg 8861 4019 Operating Ibs kg 9564 4338 Shipping Ibs kg 11261 5108 Operating Ibs kg 11964 5427 WDC050 1812 1812 9217 4181 10018 4544 11617 5269 12418 5633 WDC050 1816 1816 10468 4748 11268 5111 12868 5837 13668 6200 WDC050 2012 1812 9671 4387 10534 4778 12071 5475 12934 5867 WDC050 2016 1816 11024 5000 12110 5493 13424 6089 14510 6582 WDC050 2212 2212 11123
33. 762 1854 737 432 2870 406 3759 406 2870 406 3759 432 2870 432 3759 432 2870 432 3759 Consul unit Certified Drawing for detailed dimensions of water oil cooler and relief valve connections Dimensions in inches mm See Physical Data and Weights section for component and unit weights Allow three feet of service access on all four sides Allow the length of the tubes plus two feet on one end for tube removal The last two numbers in the vessel code are the tube length in feet Mounting holes are 1 1 8 in 2 9 cm diameter Approximate thickness of waffle pad when compressed 1 in 63 cm 111 2819 CONNECTIONS OVERALL WIDTH W O CENTER OF GRAVITY FOOTPRINT STARTER pr COND _ _ 2 gt PASS PASS 34 1067 864 Product Manual PM WSC WDC 2 Figure 10 WSC 063 160 to 300 tons MAY E us 22 i l EVAPORATOR sde CONDENSER A A VESSEL CODE OVERALL LENGTH OVERALL CONNECTIONS WIDTH W O CENTER OF G
34. 787 16233 See Note 34427 15616 39875 18087 See Note WDC100 4216 4216 50470 22893 57463 26065 See Note See Note WDC100 4816 4816 See Note See Note WDC100 4220 4220 54802 24858 63248 28689 See Note See Note WDC100 WDC126 4820 4820 3616 3616 65964 29921 41816 18967 46513 21098 See Note See Note See Note See Note WDC126 4216 4216 50470 22893 57463 26065 See Note See Note WDC126 4816 4816 59185 26846 68996 31296 See Note See Note WDC126 4220 4220 54802 24858 63248 28689 See Note See Note WDC126 4224 4224 62519 28358 72345 32815 See Note See Note WDC126 4820 4820 59185 26846 65964 29921 See Note See Note WDC126 4824 4824 Product Manual PM WSC WDC 2 75831 34396 Note Unit not available with factory mounted starters 89410 40556 See Note See Note 47 Electrical Data Motor and Voltage Code The typical unit model number below displays the three digits used to identify the motor and voltage codes WSC 126K BS 72 R Motor Code Voltage Code The motor described by motor and voltage code letters will determine the maximum kW locked rotor amperes power fac
35. 8 es 88 se 1012 1011 1011 1014 1014 tota 7090 6748 5613 1428 1022 825 88 ee ss 88 ss 88 6059 5040 1304 872 756 1 7 Product Manual PM WSC WDC 2 49 50 Hertz Mot r Gode Nominal SHp Voltage Code E v F G k H 6 J j a8 o 8 8 Maxkw 73 73 73 73 73 73 E i Sina sere em DEC E TON Id dA Power Factor Maxkw 59 89 90 90 o 89 T wag Has e 3 o a a s qp 0 0p o gt A E Locked Rotor Amps 1278 850 656 690 716 899 Power Factor O Maxkw se 86 so s8 87 8 a35 hxw ne na f na f ns e f ns A A qp o vr v i _ Locked Rotor Amps 1434 910 746 785 s1 717 Power Factor O MaxkW 87 86 88 87 8 87 J Max kW Locked Rotor Amps Power Factor O Max kW 15 150 063 to 087 Max kW Locked Rotor Amps Power Factor O Max kW 16 154 063 to 087 Max kW 06810087 Locked Rotor Amps 2949 1647 1324 1399 1ass i Power Factor Max kW 90 89 90 89 89 90 o pp Mer Mew Coe osasco E E 0680087 Locked Rotor Amps 2544 1065 3498 1585 1638 3272 po PowerFadorQ MaxkW 89 ss s se ws 80 7 sas E ew To OT OT op ML o e ia w 0680087 Locked Rotor Amps Pp o o po ise es
36. ACdrop panel is a gateway that allows any BACnet M based building automation system BAS to communicate with MicroTech unit or supervisory controllers The panel translates between the standard BACnet protocol ANSI ASHRAE 135 1995 and the McQuay protocol No modifications to the MicroTech hardware is necessary Product Manual PM WSC WDC 2 21 22 Building Management Systems All MicroTech unit controllers and system controllers are capable of Open Protocol communications providing seamless integration and comprehensive monitoring control and two way data exchange with virtually all Building Management Systems Here are just a few of the 220 points on a WDC chiller that are available remotely through one simple low cost twisted pair interface Operating Parameters Safety Cycling Conditions Entering leaving water temperatures High and low refrigerant pressures Refrigerant temperatures and pressures Oil pressure differential Motor amps as a percent of FLA Motor condition from embedded sensors Hours of operation and number of starts System water pump failures Chilled water and demand limit setpoints High discharge temperatures Cause and conditions for last eight shutdowns Starter fault Multiple Machine Control Two WSC Units or One WDC Dual Compressor Unit The lead lag load balance function is a standard feature of each MicroTech panel It provides sequencing control load balancing and single point control for BMS interface for reset o
37. BOUT VERTICAL C L LEFT HAND CONNECTION IS MIRROR IMAGE OF ABOVE OUTLETS ARE MIRRORED ABOUT HORIZONTAL C L Dimensions with Victaulic or Flanged Connections 150 PSI Non ASME Victaulic Connection Return 1 PASS 2 PASS 3 PASS Head B RAR BBB OCO DDD E AAA BBB CCO DDD EEE TEE aca AAA BBD CC DDD ESE EFE UU 13 25 10 19 14 00 11 81 15 00 13 25 Consult Factory Return Head ARA BBB coe DoD EEE TA AAA BBB CCO DDD EEE TEE fece AAA BBB CCC H Fr UU Cond 1 PASS 2 PASS 3 PASS Dia 10 00 8 625 10 00 8 625 Consult Factory Consult Factory Product Manual PM WSC WDC 2 Marine Water Boxes WDC 2 and 4 Pass Cond Except 18 in 2 Pass Evap And Cond 1 Pass Nozzle Flanges Are Optional 50 pj 2 and 4 Pass Cond Except 18 in 2 Pass All 2 Pass Evap All 3 Pass Cond 18 in 2 Pass Cond Nozzle Flanges Are Optional Nozzle Flanges Are Optional 50 Notes 1 Evaporator connections are front facing only 2 Condenser connections are rear facing only Outline dimensions Cover Connections Vessel D Thick i Fig2 Fig3 Fig4 i ness Pipe Size For Passes 1P 2P 3P 4P j NININA gt Notes See notes on previous page Product Manual PM WSC WDC 2 45 46 Weights WSC050 Evaporator Condenser Size 1809 1609 Max Unit W
38. COOLANT SUCTION FIL TER DRIER E SERVICE PERELE PENR SHUTOFF VALVE SOLENOID VALVE F EVAPORATOR RE ENTRY OF FILTERED MOTOR COOLANT INTO MAIN SYSTEM p t dM vi E Um L t 3 S MT 4 LIQUID REFRIG AER y TS E FILTER DRIER rt DISCHARGE ON m X uk CHECK PUMP 4 Y VALVE EXPANSION VALVE o a PILOT OPERATED I Y b q CONDENSER tn L m Fp Kre Al V a E fi 4 F ts 1 f t Ba MAIN CONDENSER SERVICE SHUTOFF 7 a sa M q VIC s J SHUTOFF VALVE VALVE MOTOR COOLANT FEED LINE Product Manual PM WSC WDC 2 17 Part Load Efficiency Chillers usually spend 99 of their operating hours under part load conditions and as illustrated on page 4 most of this time at less that 6096 of design capacity One compressor of a dual chiller operates with the full heat transfer surface of the entire unit for example one 500 ton 1 750 kW compressor on a 1 000 ton 3 500 kW chiller utilizes 1 000 tons 3500 kW of evaporator and condenser surface This increases its capacity and also results in very high efficiency Typical efficiencies for a dual compressor chiller taken from a computer run look like this e Full load efficiency 0 550 kW per ton 6 5 COP e 60 load one compressor 0 364 kW per ton 9 6 COP s IPLV 0 415 kW per ton 8 5COP The addition of VFDs to the dual compressor chiller produces an astonishing ARI Certified IPLV of 0 340 for the above case Specific selections can vary up or down fro
39. EMA 12 Dust tight enclosure For use in dusty areas Controls English or Metric Display Either English or metric units for operator ease of use Modem for remote monitoring Includes the modem required for remote monitoring one or more units Requires Monitor software Monitor software Required for installation in a PC to complete remote monitoring capability Product Manual PM WSC WDC 2 Chiller System Controller Details described in the Control Section of this manual Unit Export packaging Can be either slat or full crate for additional protection during shipment Units normally shipped in containers Pumpout Unit with or without storage vessel Available in a variety of sizes Details under the Pumpout section of this manual Refrigerant monitor For remote mounting including accessories such as 4 20ma signal strobe light audible horn air pick up filter Hot gas bypass For operation below 10 on WSC and 5 on WDC units Reduces cycling and its attendant water temperature swings Sound attenuation package Consists of acoustical insulation on the discharge line Extended warranties Extended 1 2 3 or 4 year warranties for parts only or for parts and labor are available for the entire unit or compressor motor only Witness performance test The standard full load run test is performed in the presence of the customer under the supervision of a McQuay engineer includes compilation of the test data Travel and local exp
40. HRAE Standard 15 The common header can be calculated by the formula 0 5 2 2 2 DCommon o D5 Del WARNING The above information is a guide only Consult local codes and or latest version of ASHRAE Standard 15 for sizing data Refrigerant Recovery Units Although McQuay chillers can pump the entire refrigerant charge into the condenser and valve it off there are occasions when pumpout units are required due purely to specification requirements or unusual job considerations McQuay offers three sizes of refrigerant recovery units and two sizes of storage receivers They are sold separately and one recovery unit can be factory mounted on the storage vessel Recovery units are ETL listed Capacities for R 22 are ARI certified Storage tanks are designed constructed and stamped in accordance with ASME standards Table 5 Size and Specifications 1 R 22 Liquid 1 R 22 Vapor T Dimensions Transfer Rate Transfer Rate Comp SE ite LxWxH Electrical lb m kg m Lb m kg m HP 9 Inch mm RRU134 5 55 25 1 56 0 71 300 1050 115 52 E S i m 1 60 115 RRU134 3 55 25 1 56 0 71 300 1050 115 52 Es aa 1 60 230 RRUS70 3 325 148 1000 3500 190 86 ME ips m 1 60 230 3 6 0 2 7 6 0 2 7 RRU999 D 500 227 0 4 75 Yo Io 1286 3 60 575 NOTES 1 Transfer rate for R 22 is ARI certified 2 Suggested maximum chiller capacity Refrigerant Compatibility Units are suitable for use with the following refrigerants
41. Model Max Amps Power Cooling VFD 019 3 60 460 480 Air VFD 025 3 60 460 480 Air VFD 047 3 60 460 480 VFD 060 3 60 460 480 VFD 072 3 60 460 480 VFD 090 3 60 460 480 VFD120 3 60 460 480 VFD Mounting VFDs can be factory mounted on the same units and in the same location as conventional starters or can be freestanding as shown below Chiller Model Unit Mounted at Unit Mounted in Free Standing 2 Factory 1 Field WSC WDC 050 087 X X WSC 100 126 X 3 X X WDC 100 126 Notes 1 2 3 Optional reactor is field mounted and wired to unit mounted VFD Optional reactor is factory mounted in the VFD enclosure Brackets and interconnecting cables shipped with unit Product Manual PM WSC WDC 2 59 60 VFD Line Harmonics Despite their many benefits care must be taken when applying VFDs due to the effect of line harmonics on the electric system VFDs cause distortion of the ac line because they are nonlinear loads that is they don t draw sinusoidal current from the line They draw their current from only the peaks of the ac line thereby flattening the top of the voltage waveform Some other nonlinear loads are electronic ballasts and uninterruptible power supplies Line harmonics and their associated distortion may be critical to ac drive users for three reasons 1 Current harmonics can cause additional heating to transformers conductors and switchgear 2 Voltage harmonics
42. NNNNVY stability at low loads is the unique McQuay moveable discharge impels Impeller laai geometry Less refrigerant is circulated as the chiller capacity reduces The left drawing shows the operation at full load of a unit with a fixed compressor discharge cross section At full load a large quantity of gas is discharged with a fairly uniform discharge velocity as indicated by the arrows The middle drawing shows a fixed compressor discharge at reduced capacity Note that the velocity is not uniform and the refrigerant tends to reenter the impeller This is caused by low velocity in the discharge area and the high pressure in the condenser resulting in unstable surge operation and with noise and vibration generated The right side drawing shows the unique McQuay moveable discharge geometry As the capacity reduces the moveable unloader piston travels inward reducing the discharge cross section area and maintaining the refrigerant velocity This arrangement allows capacity reduction to 1046 of full load Discharge Line Sound Packages For the extremely sensitive projects an optional discharge line sound package is offered consisting of sound insulation installed on the unit s discharge line An additional 2 to 4 dbA reductions normally occurs ARI Standard 575 Sound Ratings Product Manual PM WSC WDC 2 25 26 Sound data in accordance with ARI 575 for individual units are available from your loc
43. ONAL STARTER OPTIONAL FOOTPRINT VESSEL CODE OVERALL LENGTH Toyemar OVERALL Canaria HEIGHT WIDTH W O CENTER OF GRAVITY FOOTPRINT EVAP COND PASS PASS BOTH ENDS STARTER 2 2 A TAT A jag c j x yJ z pp F f a PASS PASS 221 214 221 95 57 93 46 18 199 196 57 49 ote caote voco ER 5620 224 218 224 100 72 93 47 32 199 196 57 49 cse o eae 224 218 224 106 74 94 50 32 199 PARA ree E3616 3616 5698 5531 4974 1886 1682 12 12 Note See notes on page 34 Product Manual PM WSC WDC 2 41 Figure 17 WDC 100 1200 to 1700 tons 16 foot shells WDC 126 1600 to 2700 tons 16 foot shells Ke li CONDENSER LC Xv Ze e 224 218 224 104 95 93 51 40 199 196 95 87 E 224 219 224 107 100 94 50 44 199 196 100 92 re care 230 224 230 116 10 95 52 51 199 196 110 102 Note See notes on page 34 VESSEL CODE OVERALLLENGTH Toyeran OVERALL CONNECTIONS 183 2 HEADCONN yeigur WIDTH w o CENTER OF GRAVITY FOOTPRINT EVAP T COND EVAP COND PASS PASS BOTH ENDS STARTER W O STARTER 2 2 B8 PASS PASS Product Manual PM WSC WDC 2 Figure 18 WDC 100 1200 to 1700 tons 20 24 foot shells WDC 126 1600 to 2700 tons 20 24 foot shells FOOTPRINT VESSEL CODE OVERALL LENGTH overaLL OVERALL HEIGHT WIDTH W O CENTER OF GRAVITY FOOTPRINT EVAP EVAP COND PASS PASS BOTH ENDS STARTER 2 2 LALALA I
44. ONENTS A Compressor 1 Unit shall have a single stage hermetic centrifugal compressor Casing design shall ensure major wearing parts main bearings and thrust bearings are accessible for maintenance and replacement The lubrication system shall protect machine during coast down period resulting from a loss of electrical power The impeller shall be statically and dynamically balanced The compressor shall be vibration tested and not exceed a level of 0 14 IPS Movable inlet guide vanes actuated by an internal oil pressure driven piston shall accomplish unloading Compressors using an unloading system that requires penetrations through the compressor housing for linkages that must be lubricated and adjusted are acceptable provided the manufacturer provides a five year inspection agreement consisting of semi annual inspection lubrication and annual change out of any compressor seals A statement of inclusion must accompany any quotations If the compressor is not equipped with guide vanes for each stage and movable discharge diffusers then furnish hot gas bypass and select chillers at 5 lower kW ton than specified to compensate for bypass inefficiency at low loads Lubrication System The compressor shall have an independent lubrication system to provide lubrication to all parts requiring oil Provide a heater in the oil sump to maintain oil at sufficient temperature to minimize affinity of refrigerant and a thermostatically con
45. RAVITY FOOTPRINT EVAP COND STARTER 2 OVERALL 183 VAP COND PASS E 134 E2009 C1809 3404 169 E2012 C1812 4293 134 E2209 C2009 3404 169 E2212 C2012 4293 134 E2209 C2209 3404 6 E2212 C2212 4293 34 0 6 1 4 1 129 134 0 1 0 E2612 C2212 4293 134 E2609 C2609 8404 169 E2612 C2612 4293 14 E3009 C2609 3556 14 E3009 C3009 3556 Note See notes on page 34 9 4 9 175 E3012 C2612 4445 0 0 128 3251 134 3404 164 164 Product Manual PM WSC WDC 2 2 HEAD CONN 4140 4293 1930 3277 3404 1930 4166 4293 1930 3277 3404 1930 4293 1930 8 169 8 129 134 86 4166 4293 2184 4242 4445 2286 3353 3556 2235 3353 3556 2438 LB 76 1930 0 x Y E LEA 3 42 50 7 1270 940 1067 1727 91 1067 1270 91 1067 1727 86 8 8 9 6 4 6 4 4 5 9 4 7 0 5 1067 4 1067 1295 88 1067 1727 86 1168 1295 94 1168 1753 889 1219 1295 1016 1219 1753 965 1346 1702 1041 1321 1321 1041 1372 1321 1092 406 2870 432 3759 432 2870 432 3759 432 2870 432 3759 508 2870 508 3759 508 2870 533 3759 533 3759 635 2870 660 2870 111 2819 145 9683 111 2819 145 3683 111 2819 145 3683 111 2819 145 3683
46. T 315 315 314 314 84 f 2536 2329 2638 2758 2210 89 90 90 88 86 8 T 350 350 850 350 350 5968 3482 2725 2854 2983 21988 T Power Factor Max kW 89 87 90 89 88 89 90 89 88 90 T MaxkW 388 388 388 388 388 368 388 368 388 38 90 90 pS ri pp 90 91 90 88 87 90 88 86 Locked Rotor Amps 7045 7339 5898 6177 6456 3589 2957 3097 3238 2753 Power Factor O Max kW 91 90 91 90 89 91 91 90 89 89 Loo MaxkW j Max kW 3e 392 392 395 LokedRoorAms 1 J T T T J9548 240 33 184 Power Factor Maxkw T T T T1 T J T j 9 se 90 MaxkW 447 447 447 447 447 447 447 447 447 447 Locked Rotor Amps 8412 8763 7286 7632 7979 4279 3642 3815 3989 3053 J T T Power Factor O MaxkW 89 87 90 88 86 89 90 se 86 es T L MaxkW pp a4e sa4s 452 453 LockedRotorAmps Power Factor O MaxkW EN Mas N __ Locked Rotor Amps EEE Power Factor O MaxkW HEM Po La L Maxkw 66 466 465 465 466 470 469 469 LockedRotorAmps 304 3665 3839 4013 2736 693 485 401 Power Factor MaxkW
47. T T Power Factor Maxkw 86 83 90 88 se 9 90 s se se j Continued on next page 48 Product Manual PM WSC WDC 2 Compressor Motor Data 60 Hz continued Motor Code Nominal SHp 29 290 063 to 087 32 320 063 to 087 35 350 063 to 087 40 400 063 to 087 47 450 063 to 087 49 500 063 to 087 50 500 063 to 087 57 575 063 to 087 58 575 063 to 087 61 600 100 to 126 62 600 100 to 126 65 650 063 to 087 66 650 063 to 087 72 725 100 to 126 73 725 100 to 126 84 850 100 to 126 85 850 100 to 126 KO 1000 100 to 126 NO 1000 100 to 126 N1 1100 100 to 126 N2 1200 100 to 126 N3 1300 100 to 126 VoltageCode N B Pe v wy ularn s np nw ec y se je 220 229 242 253 264 418 484 506 528 633 2640 3630 4575 7260 Maxkw 1 228 228 228 228 228 228 228 228 227 228 Locked Rotor Amps 3678 3839 3643 3832 4023 2151 1672 1742 1828 1392 Power Factor O Max kW 90 88 86 89 90 89 88 oo aa Ojo L 1 1 25 25 251 254 LockedRotorAmps L LLL lo z6 223 117 Power Factor O Max kW ppp To f f f ee 9 275 275 275 276 275 275 276 2610 1914 2012 2118 1479 T Power Factor O Max kW 90 89 9 90 88 90
48. VA maximum coil rated condenser water pump relay CWR 1 and 2 is to be wired as shown Optional customer supplied 115 VAC 25 VA maximum coil rated cooling tower fan relays C1 C4 may be wired as shown This option will cycle the cooling tower fans in order to maintain unit head pressure Auxiliary 24 VAC rated contacts in both the chilled water and condenser water pump starters must be wired as shown All wiring to be NEC Class 1 Control Power The 115 volt control power may be supplied from the starter or a transformer meeting the requirements of McQuay Specification 3594999 separate from the starter Either source should be properly fused with 20 amp dual element fuses or with a circuit breaker selected for motor duty If the control transformer or other power source for the control panel is remote from the unit conductors must be sized for a maximum voltage drop of 3 Required circuit ampacity is 20 amps at 115 volts Conductor size for long runs between the control panel and power source based upon National Electrical Code limitations for 3 voltage drop may be determined from the table below Control Power Line Sizing Wire Size AWG Wire Size AWG 0 0 to 50 15 2 120 36 6 to 200 61 0 6 50 15 2 to 75 22 9 200 61 0 to 275 83 8 75 22 9 to 120 36 6 ls 275 83 8 to 350 106 7 Notes Maximum length is the distance a conductor will traverse between the control power source and the unit control pane
49. a time as is necessary to ensure proper operation of the unit but in no case for less than two full working days During the period of start up The Start up Technician shall instruct the Owner s representative in proper care and operation of the unit Product Manual PM WSC WDC 2 83 We reserve thr right to make change in design and construction at any time without notice McQuav International McQuay Italia S P A S S Nettunense km 12 300 00040 Cecchina Roma Italia Tel 06 937311 Fax 06 9374014 E mail mcquay mcquayitalia com
50. access for inspection cleaning and removal without dismantling water piping Flanges victaulic standard ANSI raised face flanges on either the evaporator or condenser Mating flanges are by others 0 028 or 0 035 in tube wall thickness For applications with aggressive water conditions requiring thicker tube walls Cupro nickel or titanium tube material For use with corrosive water conditions includes clad tube sheets and epoxy coated water heads Water side vessel construction of 300 psi 150 psi is standard For high pressure water systems typically high rise building construction Water differential pressure switches This option provides evaporator and condenser water pressure differential switches as a factory mounted and wired option A proof of flow device is mandatory in both the chilled water and condenser water systems Double insulation 1 12 inch on evaporator suction piping and motor barrel For high humidity locations and ice making applications No Insulation This option for cases where insulation will be applied in the field Chiller and suction line are not insulated Electrical Optional starters for factory or field mounting See details in the Motor Starter section of this manual Variable frequency drives Provides variable speed ability to the compressor for improved efficiency and soft starting NEMA 4 watertight enclosure For use where there is a possibility of water intrusion into the control panel N
51. al McQuay representative These ratings are in accordance with ARI Standard 575 Due to the large number of component combinations and variety of applications sound data is not published in this catalog Product Manual PM WSC WDC 2 Unit Selection Many combinations of compressor configuration and condensers and evaporators are available for a given capacity The units range from low first cost and relatively high kW per ton COP to high first cost and low kW per ton COP A graphic display of the optional performance available is shown at the right The COP curve would be mirrored and is not shown for clarity Optimum unit selection for maximum operating return on the invested first cost is identified as point X POINT X IS THE OPTIMUM SELECTION FOR MAXIMUM OPERATING RETURN ON THE INVESTED FIRST COST 2 O d x lt ul a CHILLER kW PER TON COP Actual optimum unit selection will vary with building application and system design Applications with minimal hours of operation may not justify a very low kW per ton COP unit CHILLER UNIT COST Applications with high hours of operation will justify high part load as well as full load efficiency units For optimum selection an energy analysis is recommended through your local McQuay Sales Representative Basic unit selections All McQuay centrifugal chillers are computer selected to optimize the cooling output and total kW Computer selection allows for the specifica
52. allows McQuay to determine compliance with IEEE 519 1991 Line reactors isolation transformers or phase shifting transformers may be required on some installations Product Manual PM WSC WDC 2 Application Considerations Pumps Model WSC and WDC chiller compressor motors operate at 3600 rpm at 60 Hz 3000 rpm at 50 Hz When VFDs are employed the hertz speed can be reduced by 70 To avoid the possibility of objectionable harmonics in the system piping the use of 4 pole 1800 1500 rpm system pumps should be used The condenser water pump s must be cycled off when the last chiller of the system cycles off This will help to maintain proper separation of oil and refrigerant within the chiller In addition turning off the condenser water pump s when the chillers are not operating will conserve energy Chilled Water Temperature The maximum temperature of water entering the chiller on standby should not exceed 110 F 43 3 C Maximum temperature entering on start up should not exceed 90 F 32 2 C Minimum chilled water leaving temperature without antifreeze is approximately 38 F 3 3 C but can vary up or down two degrees depending on actual component selection Piping Piping should be adequately supported to remove weight and strain on the fittings and connections Be sure piping is adequately insulated Install a cleanable 20 mesh water strainer upstream of the evaporator and condenser Install enough shutoff valves to permit drain
53. and modifies chiller operation to provide maximum cooling Integrated lead lag and automatic engagement of backup pump Optimum integrated control of cooling tower water based on system conditions Enables unattended starting and stopping of entire chiller plant Invaluable assist in trouble shooting operating conditions in memory Designed with the system operator in mind Reliable economic use of centrifugal chillers depends on easy operator interface That s why operation simplicity was one of the main considerations in the development of MicroTech For example all the system s status messages are shown in plain English on a 4 line by 40 character liquid crystal display LCD The display is backlit for easy viewing in all light conditions Metric units are available at no extra cost In addition to the display 18 individual touch sensitive membrane key switches provide easy access to data MicroTech s keypad is separated into four distinct functional areas Category Menu Item Action and Quick Access Product Manual PM WSC WDC 2 Nonvolatile Memory Since MicroTech s memory is nonvolatile battery backup to protect the programs and settings in case of power loss is unnecessary Versatile Communications Capabilities Give You Even More Control For complete flexibility there are four ways to interface with the MicroTech controller 1 Direct entry and readout locally at the panel on the unit 2 1 plus digital and analog
54. anslates to a readily available and competitively priced product Compressor Design Gear Drive Offers Greater Operating Efficiency Than Direct Drive Centrifugal compressor efficiency is a function of impeller design and application to the refrigeration system The increased heat transfer surface and efficiency of modern heat exchangers have changed compressor head and impeller tip speed requirements Direct drive designs limit the manufacturer s ability within a single compressor size to select impellers at or near peak impeller efficiency While a unit selected at poor impeller efficiency might produce the required performance at peak load its operating characteristics over the entire range of part load performance are sharply curtailed resulting in increased annual operating costs McQuay gear drive centrifugal chillers provide a variety of tip speed ratios to permit selection of impellers for maximum efficiency over their entire part load to full load range and are ideal for 50 Hz application Mechanical gear losses are limited by design standards to less than one half of 1 The impeller efficiency obtained by alternate gear selections may increase chiller efficiency by as much as 796 As energy costs continue to rise the economic advantages of gear drive to obtain maximum efficiencies will be universally sought The efficiency of either direct drive or gear drive compressor can be improved through the use of variable frequency drives to reduce c
55. as been shut off This delay interval provides time for the chilled water pump to circulate system water and impart a valid system water temperature to the chilled water sensor Temperature control operation Temperature sensors are negative coefficient thermistors selected for extended accuracy and close control During compressor operation from 10 to 100 capacity chilled water temperature will be held to within 0 2 degrees F 0 12 degrees C As building cooling load is decreased the compressor inlet vanes will close as required to match building load down to 10 of full capacity A further decrease in the cooling load will lower the leaving chilled water temperature The control system will permit a total of 3 to 10 degrees F 1 6 to 5 5 degrees C user adjustable overcooling of the chilled water preventing rapid restarting and or elevation of the chilled water temperature above the setpoint When the chilled water temperature is depressed to the shutoff differential setpoint the compressor motor is de energized The oil pump motor continues to run during the compressor coast down period and is timed off automatically If there is still some load on the chilled water its temperature will rise until it reaches the cycle on temperature setting At this point the compressor will initiate its start cycle and commence operation Product Manual PM WSC WDC 2 Sound Sound Levels One Of The Quietest Centrifugal Chillers In The Industry McQu
56. ater flow increases the chiller s condensing pressure increasing the lift that the compressor must overcome which in turn increases energy use Consequently pump energy savings can be lost because the chiller operating power is significantly increased Free Cooling There are several systems available to achieve free cooling when ambient air temperatures are low enough to reject building heat to the atmosphere without compressor operation The use of a plate and frame heat exchanger to exchange heat from the chilled water to the cooling tower water and ultimately to atmosphere is the most common today McQuay chillers are well suited to this application and as with all chillers attention must be paid to the system design particularly to the valves and piping involved in switching from the tower economizer free cooling cycle to normal compressor operation Vibration Mounting Every McQuay chiller is run tested and compressor vibration is measured and limited to a maximum rate of 0 14 inches per second which is considerably more stringent than other available compressors Consequently floor mounted spring isolators are not required Rubber mounting pads are shipped with each unit It is wise to continue to use piping flexible connectors to reduce sound transmitted into the pipe and to allow for expansion and contraction Product Manual PM WSC WDC 2 65 Options and Accessories 66 Vessels Marine water boxes Provides tube
57. ay centrifugal chillers are one of the quietest units available in the marketplace It is easy to make this type of claim For us it is just as easy to support Unique Quiet full load sound levels and QUIETER part load sound levels The highest noise levels for McQuay chillers are at FULL load As McQuay chillers unload noise levels reduce Other chillers on the market are typically the opposite with higher sound levels at part load Be certain to compare noise levels at several load conditions Unique Liquid refrigerant injection into compressor discharge Although this sounds complex this feature is quite simple Most of the noise in all centrifugal compressors results from high gas velocity in the discharge line The McQuay liquid injection system injects liquid refrigerant into the discharge gas through a radial array of ports This refrigerant mist absorbs sound energy much like a foggy day and the flash gas cools the discharge gas leaving the compressor The net result is significant noise reduction ADDITIONALLY Figure 7 Moveable Diffuser Geometry By removing superheat Gas Flow at Discharge of Gas Flow with from the discharge gas Impeller with Fixed Diffuser Movable Diffuser the condenser becomes Full Load Surge at Part Load Part Load more efficient improving unit efficiency Unique Moveable Discharge Geometry The other unique feature to reduce NNWNW noise and increase Wy N
58. b Evaporator suction discharge condenser and liquid temperatures c Suction and discharge superheat d Liquid subcooling evaporator and condenser approach temperatures e Evaporator condenser and lift pressures f Oil feed and sump temperatures g Oil pump discharge and oil differential pressure h Motor amps and amps as a percent of rated load amps 1 Hours of operation and number of starts time of last start and stop j Chilled water setpoint and reset temperature setpoint k Amp limit for manual and remote D History of last 8 failures with date and time plus critical sensor values m Unit status start up and shutdown sequence operational status The microprocessor shall either unload or shut down one or both compressors during an abnormal condition At a minimum the following safeties shall be incorporated in the control system a Highandlow discharge pressure b Low evaporator pressure c High discharge temperature d Chilled or condenser water pump failure e No evaporator or condenser water flow f Highorlow oil feed temperature g Low oil differential pressure h High motor temperature low motor current i Surge high suction superheat j Starter fault no starter transition k Vanes open during start sequence D Sensor failure specific to sensor Controller shall hold leaving chilled water temperature to within 0 2 F without hunting droop or overshooting Controller shall be able to limit motor amps
59. chilled water for oil cooling will often start with warm chilled Oil Cooler Data water in the system until the chilled water Flow Pross loop temperature is pulled down Data given Unit Model gpm Drop ft Inlet F Outlet F here is for that condition With cooling water 063 087 12 32 00 79 in the 40 F to 55 F 4 C to 13 C range 100 126 22 31 80 0 87 3 considerably less water will be used and the Note 1 Pressure drops include valve on the unit pressure drop will be greatly reduced 2 Multiply flow by two for dual compressor units Product Manual PM WSC WDC 2 63 64 When supplied with city water the oil piping should discharge through a trap into an open drain to prevent draining the cooler by siphoning The city water may also be used for cooling tower makeup by discharging it into the tower sump from a point above the highest possible water level NOTE Particular attention must be paid to chillers with variable chilled water flow through the evaporator The pressure drop available at low flow rates may very well be insufficient to supply the oil cooler with enough water In this case an auxiliary booster pump can be used or city water employed CONNECTION SIZES WDC 100 126 have 1 1 2 in FPT connections all other WDC and WSCs are 1 in FPT Figure 22 Oil Cooler Piping Across Chilled Water Pump PUMP y gt gt x c T CHILLER du py pA STRAINER MAX 40 MESH DRAIN VALVE ORPLUG
60. cuum prevention system for each chiller The system shall constantly maintain 0 05 psig inside the vessel during non operational periods The system shall consist of a precision pressure controller two silicon blanket heaters a pressure transducer and solid state safety circuit Refrigerant Detection Device HCFC 123 Chillers Only Chiller manufacturer shall supply and install a refrigerant detection device and alarm capable of monitoring refrigerant at a level of 10 ppm Due to the critical nature of this device and possible owner liability the chiller manufacturer shall guarantee and maintain the detection monitor for five years after owner acceptance of the system Waffle type vibration pads for field mounting under unit feet Product Manual PM WSC WDC 2 PART 3 EXECUTION 3 1 INSTALLATION A Install per manufacturer s requirements shop drawings and Contract Documents B Adjust chiller alignment on foundations or subbases as called for on drawings C Arrange piping to allow for dismantling to permit head removal and tube cleaning D Furnish and install necessary auxiliary water piping for oil cooler E Coordinate electrical installation with electrical contractor F Coordinate controls with control contractor G Provide all materiel required to ensure a fully operational and functional chiller 3 2 START UP A Units shall be factory charged with the proper refrigerant and oil B Factory Start Up Services Provide for as long
61. d at maximum efficiency i e no hot gas bypass Optimum compressor efficiency is designed into each McQuay impeller Each is cast fully shrouded by the lost wax process that provides exact duplication despite a complex configuration of 16 backward inclined blades The McQuay designed impeller not only minimizes pressure loss at the inlet and maximizes compression efficiency but also breaks up pure tone sound to operate at competitively low sound power levels A simple short diffuser and a volute design passing compressed gas directly into the condenser maintain the compressor efficiency The REAL FACTS on Speed Rpm and Tip Speed in Centrifugal Compressors The question How fast does it spin is a common curiosity when discussing compressors There is a widespread idea promoted by manufacturers of direct drive compressors that rpm is the determining factor in the life reliability and efficiency of the compressor This is absolutely false An engineering examination will show that rpm as an absolute is not considered in the design of rotating mechanical components It is the combination of velocity of the outside edge of the impeller tip speed mass and physical size that define the design criteria for these components Shaft bearing and impeller design is based on parameters such as surface velocity diameter weight rotational and torsional critical speed as well as the type of material and lubrication system used Stress on an impelle
62. d can be shown by the following equation rpm TipSpeed fps x229 2 Diameter in rpm TipSpeed m 5 x1910 Diameter cm Again this indicates that for a given speed requirement a smaller diameter impeller in a compressor will operate at a higher rpm than a larger diameter impeller Again Stress Tip Speed Impellers with similar tip speeds have similar stress Since the impeller shaft must be sized to support the static rotational and torsional loads applied by the impeller as impellers become larger shafts must also become proportionally larger These factors also come into play in the design or selection of a bearing The primary criteria used in bearing design are 1 The load per unit of bearing area 2 The relative velocity of the two bearing surfaces 3 The bearing dimensions 4 The viscosity of the lubricating oil Notice that item 2 returns to the phenomenon of tip speed Surface velocity is simply the tip speed of the inner bearing surface or shaft with respect to the outer bearing surface as illustrated below Figure 2 Bearing Loading Cut Cross Section and Spread Out QO Tip Speed i 1 Shaft Bearing Velocity Equal to the Tip Speed Shall Surface Surface Velocity of the Bearing Bearing Surface T A bearing is basically two infinite surfaces passing over one another with a velocity equal to the surface velocity Bearing design and consequently bearing life is determin
63. d mounting brackets and interconnecting cables are shipped with the unit E3012 C3012 available on 100 only E4812 C4812 available on 126 only See notes on page 34 37 Figure 13 WDC 048 050 180 to 320 tons EVAPORATOR CONDENSER FOOTPRINT VESSEL CODE 183 VAP COND PASS 169 E2212 C2212 4299 2 E2216 C2216 5544 Ear 1 E E2412 C2212 4299 E2416 18 69 218 C2216 5544 69 E2612 C2212 4299 8 E2616 21 C2216 5544 OVERALL LENGTH OVERALL OVERALL rae HEIGHT WIDTH W O CENTER OF GRAVITY FOOTPRINT PASS BOTH ENDS STARTER a B c x Y z D E F s 4158 4299 2020 1024 1838 733 384 3802 3726 1024 872 5404 5544 2020 1024 2367 800 498 5050 4974 1024 872 4180 4299 2149 1131 1854 838 457 3802 3726 1131 979 5544 2108 1092 2413 86 496 5050 4974 1092 965 4299 2149 1131 1918 505 3726 1131 979 5544 2149 1131 2467 492 1131 979 5428 165 150 4180 90 3802 6 199 196 21 5050 4974 214 5428 Note See notes on page 34 CONNECTIONS EVAP COND 2 2 PASS PASS Product Manual PM WSC WDC 2 Figure 14 WDC 063 320 to 600 tons
64. e es Power Factor 6 MaxkW o po a es e e e E Ma A e e ecc ele gt A cs 0680087 Locked Rotor Amps 2740 2027 1577 1666 1788 342 po Power Factor 6 Max kW 90 88 s so we 9 7 meo C mw AO PO A A cnt es pedes pter 3 06810087 Locked Rotor Amps pp ie es 1 es es Power Factor 6 Max kW f M o o ms e e e A A E A AAA 23 242 TockedRotor mps 3281 231i 1688 1771 3849 1680 o 06310087 PowerFadorQ MaxkW 88 as so s we e 7 25 250 06310087 PowerFactorOMaxkw 88 8 8 87 85 87 se do 99 87 gt MakWw 230 24 231 29 23 po 7 29 292 Looked Rotor Amps 3375 2005 1928 2044 2135 1687 o 06310087 PowerFactorOMaxkW 90 as 80 s a7 9 maxi 28 228 220 228 28 eee 7 31 292 Locked Rotor Amps 3666 2993 2179 2298 2388 wee o 06310087 Power Factor O MaxkW 90 85 90 88 amp 89 7 E mw SC CETTE SO sen E prre DE 32 340 Looked RotorAmps o o o o oa pao 14 ws 06310087 PowerFactorOMaxkW o o o e se ss Do MakW 280 260 20 20 2 0 po 34 933 Locked Rotor Amps 4366 3267 2468 2605 2704 249 M 7 06310087 Power Factor O Max
65. ecific application conditions is required The complete unit model code is then established as follows Figure 8 Chiller Identification MODEL CODE EXAMPLE WSC 063K AQ 18S E2012 QE 2 A C1812 TNY Y 2 AY Y Y 134 NE Packaged Water Cooled Centrifugal Chiller S Single Compressor 9 D Dual Compressor S Hermetic Compressor Model Compressor Impeller Code E Gear Ratio Motor Voltage Code Evaporator Shell Description Diameter in Length ft S Tube Count Code S Tube Type Code lt Number of Passes 1 2 3 E Water Inlet Location R Right Inlet L Left Inlet Connection Type Condenser Shell Description Diameter in Length ft Tube Count Code Type Type Code Tube Count Code Heat Recovery Condenser x Tube Type Code Heat Recovery Conderser S Number of Passes 1 2 3 Z Water Inlet Location R Right Inlet L Left Inlet Connection Type Number of Passes Heat Recovery Condenser Water Inlet Location Heat Recovery Condenser Connection Type Heat Recovery Condenser X Refrigeration Type 134 HFC 134a Product Manual PM WSC WDC 2 29 30 Physical Data and Weights Evaporator The insulation of cold surfaces includes the evaporator and non connection water head suction piping compressor inlet motor housing and motor coolant suction li
66. ed by competitors efficiency claims at non standard conditions IPLV conditions are set by ARI and subject to stringent testing Insist on ARI certified IPLV efficiency when making comparisons The Redundancy Feature The McQuay Dual Centrifugal Chillers have two of everything connected to a common evaporator and condenser Two compressors two lubrication systems two control systems two starters Should a failure occur to any component on a compressor system the component can be removed or repaired without shutting down the other compressor an automatic back up with 60 percent of the chiller design capacity available In the unlikely event of a motor burnout the chiller refrigerant charge will not be contaminated This is so well proven that it is guaranteed for five years In areas supported by McQuayService should a motor burnout contaminate the refrigerant in the chiller the charge will be replaced free for a period of five years from start up Product Manual PM WSC WDC 2 Why a Compressor Motor Failure Will Not Contaminate the Common Refrigerant Circuit The compressor motor is isolated from the main refrigerant flow circuit so that any contaminants generated by a motor fault will not pass into the main refrigerant circuit Moisture acid and or carbon particles would be automatically trapped within the dedicated coolant feed and exit lines Internally the compressor motor compartment is separated and sealed from the main re
67. ed largely by the above criteria Rpm by itself as an absolute is only one half of the equation in the design process One can also see that higher rpm and smaller lighter parts actually reduce the load and wear on bearings It is the surface velocity in conjunction with the load to be supported that determines bearing life and therefore bearing selection Referring to the analogy of the tractor trailer versus the utility trailer one sees that even though the utility trailer tires operate at a much higher rpm the tractor trailer wheel bearings must be much more massive due to the much heavier dynamic loading Shaft rotating speed has little effect on bearing wear The smaller rotating mass of a machine will improve the life of the bearing Before the shaft begins to spin it rests on the bearing surface Once the shaft starts rotating an oil film develops between the shaft and the bearing that supports the shaft The low mass of a positive pressure machine not only exerts a smaller static load on the bearings but the fast spin up enabled by the low inertia of the modern gear drive compressor permits the supportive oil film to build up more quickly These two characteristics drastically reduce wear on the compressor at the time it is most likely to occur The same phenomenon although less extreme also holds true during coast down The quicker the better Product Manual PM WSC WDC 2 11 12 The table at the right compares refrigerants in commo
68. een the evaporator and condenser are usually similar to normal cooling applications The leaving fluid temperature is lower but the condensing temperature is also lower because the cooling tower water is colder If the ice mode can also operate during the day when cooling tower water temperatures are high a proper selection becomes more difficult because the two refrigerant pressure differentials are significantly different A three way condenser water control valve is always required Variable Speed Pumping Variable speed pumping involves changing system water flow relative to cooling load changes McQuay centrifugal chillers are designed for this duty with two limitations First the rate of change in the water flow needs to be slow not greater than 2 per minute The chiller needs time to sense a load change and respond Second the water velocity in the vessels must remain between 3 and 10 fps 0 91 and 3 0 m sec Below 3 fps 0 91 m sec laminar flow occurs which reduces heat transfer Above 10 fps 3 0 m sec excessively high pressure drops and tube erosion occur These flow limits can be determined from the McQuay selection program We recommend variable flow only in the evaporator because there is virtually no change in chiller efficiency compared to constant flow Although variable speed pumping can be done in the condenser loop it is usually unwise The intent of variable flow is to reduce pump horsepower However reducing condenser w
69. eight Without Starter Max Unit Weight With Starter Shipping Ibs kg 5771 2618 Operating Ibs kg 6168 2798 Shipping Ibs kg 6972 3162 Operating Ibs kg WSC050 1812 1612 6504 2950 7004 3177 7704 3495 WSC050 2009 1609 6130 2781 6591 2990 7330 3326 WSC050 2012 1612 6933 3145 7510 3407 8133 3689 WSC050 2009 1809 6932 3144 WSC050 2012 1812 7267 3296 8467 3841 WSC050 2209 2009 7038 3192 7760 3520 8238 3737 WSC050 WSC063 2212 2012 2009 1809 8077 3664 6395 2901 8412 3816 8972 4070 8949 4059 9277 4208 9612 4360 10172 10149 4614 4604 WSC063 2012 1812 9284 4211 9955 4516 11155 5060 WSC063 2209 2009 9119 4136 9841 7938 3601 4464 11040 5008 WSC063 2212 2012 10182 4619 11077 5025 12277 5569 WSC063 2209 2209 9416 4271 10235 4643 11435 5187 WSC063 2212 2212 10557 11570 5248 12770 5792 WSC063 2609 2209 10248 11258 5107 12458 5651 WSC063 2612 2212 11577 12517 5678 14017 6358 WSC063 2609 2609 10984 12228 5547 13428 6091 WSC063 2612 2612 12494 14020 6359 15220 6904 WSC063 WSCO079 3012 2612 2209
70. enses are not included Certified performance test The standard run test is performed under the supervision of a McQuay engineer data is compiled and certified Product Manual PM WSC WDC 2 67 68 Specifications SECTION 15XXX CENTRIFUGAL CHILLERS SINGLE COMPRESSOR PART 1 GENERAL 1 1 SUMMARY Section includes design performance criteria refrigerants controls and installation requirements for water cooled centrifugal chillers 1 2 REFERENCES Comply with the following codes and standards ARI 550 590 NEC ANSI ASHRAE 15 OSHA as adopted by the State ASME Section VIII 1 3 SUBMITTALS Submittals shall include the following A F Dimensioned plan and elevation view drawings including motor starter cabinet required clearances and location of all field piping and electrical connections Summaries of all auxiliary utility requirements such as electricity water air etc Summary shall indicate quality and quantity of each required utility Diagram of control system indicating points for field interface and field connection Diagram shall fully depict field and factory wiring Manufacturer s certified performance data at full load plus IPLV or NPLV Before shipment submit a certification of satisfactory completion of factory run test signed by a company officer The test shall be performed on an ARI Certified test stand and conducted according to ARI Standard 550 590 Installation and Operating Manuals
71. ents such as electricity water air etc Summary shall indicate quality and quantity of each required utility C Diagram of control system indicating points for field interface and field connection Diagram shall fully depict field and factory wiring D Manufacturer s certified performance data at full load plus IPLV or NPLV E Installation and Operating Manuals 1 4 QUALITY ASSURANCE A Qualifications Equipment manufacturer must specialize in the manufacture of the products specified and have five years experience with the equipment and refrigerant offered B Regulatory Requirements Comply with the codes and standards in Section 1 2 C Chiller manufacturer plant shall be ISO Registered 1 5 DELIVERY AND HANDLING A Chillers shall be delivered to the job site completely assembled and charged with refrigerant and oil B Comply with the manufacturer s instructions for rigging and transporting units Leave protective covers in place until installation 1 6 WARRANTY The refrigeration equipment manufacturer s warranty shall be for a period of one Or two Or five years from date of equipment start or 18 months from shipment whichever occurs first The warranty shall include parts and labor costs for the repair or replacement of defects in material or workmanship The refrigerant charge shall be warranted against contamination from a motor burnout for five years 1 7 MAINTENANCE Maintenance of the chillers shall be t
72. er the tip speed requirement To produce the required pressure difference or lift a centrifugal impeller must achieve a given tip speed Tip speed is the velocity of the tip of the impeller relative to its surroundings Imagine an observer standing on the impeller The observer sees his surroundings pass by him at a certain velocity This velocity is the impeller tip speed usually expressed in feet per second meters per second An analogy may be drawn to a car driving down a road The tip speed of the tire is equal to the speed of the car Since all the refrigerants that have been discussed require tip speeds in the range of 670 to 700 ft sec 204 to 213 m sec we see that the impeller angular velocity rpm is largely affected by its diameter It was pointed out earlier that negative pressure impellers must be larger than those in positive pressure machines due to the drastic differences in required gas flow rates Larger diameter impellers must rotate at slower rpm than smaller diameter impellers Referring again to the car example demonstrates that different combinations of diameter and rpm produce the same tip speed Imagine a freeway carrying vehicles with different size tires all traveling at 55 mph The tip speed of all of the tires is fixed at 55 mph even though the small tires of a utility trailer rotate at a much higher rpm than the large tires of a tractor trailer Product Manual PM WSC WDC 2 The relationship of diameter and tip spee
73. f the ventilation or air handling units Equipment room ventilation and safety requirements for various refrigerants is a complex subject and is updated from time to time The latest edition of ASHRAE 15 should be consulted Product Manual PM WSC WDC 2 Thermal Storage McQuay chillers are designed for use in thermal storage systems The chillers have two operating conditions that must be considered The first is normal air conditioning duty where leaving evaporator fluid temperatures range from 40 F to 45 F 4 4 C to 7 2 C The second condition occurs during the ice making process when leaving fluid temperatures are in the 22 F to 26 F 5 6 C to 3 3 C range The MicroTech control system will accommodate both operating points The ice mode can be started or stopped by a digital input signal to the microprocessor through an Open Protocol Module OPM panel or through a chilled water reset signal When a signal is received to change from the ice mode to the normal operating mode the chiller will shut down until the system fluid temperature rises to the higher setpoint The chiller will then restart and continue operation at the higher leaving fluid temperature When changing from normal cooling to the ice mode the chiller will load to maximum capacity until the lower set point is reached Computer selections must be made to insure that the chiller will operate at both conditions If the ice mode is at night the pressure differentials betw
74. frigerant compression chamber A double shaft seal on the motor side of the gear housing prevents cross flow of refrigerant within the compressor The motor coolant feed line is equipped with both a solenoid valve and a check valve These mechanical components plus the higher pressure of the liquid refrigerant prevent backfeed into the main refrigerant system Refrigerant vapor exiting the motor compartment must pass through an undersized combination filter drier The filter drier is sized to immediately plug up and seal off the motor compartment in case of a motor burnout Both the coolant feed and return lines are equipped with manual shutoff valves to permit component service Over 30 years of field experience have proven the reliability of these compressor motors Despite the reliability intended by the motor design and the protective control electrical distribution system faults and lightning strikes may occur that are beyond the control of the most conscientious designer The motor coolant s protective system protects the system A motor failure will not contaminate the common refrigerant circuit or prevent normal operation of the second compressor Figure 4 Motor Cooling VAPOR REFRIGERANT EXIT FROM MOTOR HOUSING N LIQUID REFRIG ENTRY INTO COMPRESSOR MOTOR Z FT F D l c COMPARTMENT K AD gt a L 4 T k T ads a h E rt aa ji COMPRESSOR SUCTION SHUTOFF VALVE jd Y NN E A E 1 4 RA CHECK VALVE I MOTOR
75. from 30 to 100 of RLA based on a keypad entry or by a remote 4 20mA DC signal 81 82 6 The controller shall be able to reset chilled water temperature by controlling return chilled water temperature or from a remote 4 20 mA DC signal 7 Soft loading shall be provided to prevent the unit from operating at full load during pulldown if desired 8 A time clock shall be incorporated to allow daily timed starts and stops and to allow for holiday and weekend schedule changes 9 The control system shall have automatic restart after a power failure and not require a battery backup for memory continuity A battery shall be provided for the time clock only 10 The controller shall be capable of starting and stopping chilled water and condenser water pumps It shall also be capable of four step control of cooling tower fans and analog control of a tower bypass valve 11 The microprocessor shall be capable of communicating to other units or a PC using a twisted pair communication interface of RS 232 100 feet or RS 422 485 5000 feet or with a 9600 baud modem 2 5 MISCELLANEOUS ITEMS A Pumpout System The unit shall be equipped with a pumpout system complete with a transfer pump condensing unit and storage vessel constructed according to ASME Code for Unfired Pressure Vessels and shall bear the National Boards stamp If the design of the unit allows the charge to be transferred to and isolated in the main condenser then a pumpout
76. g and compressor components in negative pressure designs to maintain reasonable gas velocity noise levels and refrigerant pressure losses Conversely the small physical size of McQuay centrifugal chillers will Permit design of smaller equipment rooms Cost less to rig and install And in smaller capacities allow transit through standard equipment room doors permitting building construction to proceed on schedule before receipt of the chiller equipment Lower joint surface area for lower likelihood of leaks Product Manual PM WSC WDC 2 Bolted Design Eases Retrofit Installation The major components evaporator condenser and compressor are bolted together and can be taken apart in the field to facilitate difficult rigging work The chillers are shipped assembled from the factory and disassembled and reassembled on site under supervision of authorized McQuay service personnel Individual component weights are shown in the Physical Data section Heat Exchangers McQuay packaged centrifugal chillers are equipped with new high performance heat exchangers The unique design greatly increases heat transfer and reduces unit footprint and refrigerant charge compared to previous designs In many cases vessel length has been reduced by 40 percent Chillers are designed constructed and tested in accordance with ASME Section VIII ASHRAE Standard 15 requirements and TEMA recommendations The replaceable water tubes are integral internally and e
77. gulating valve and solenoid valve per compressor Cooling water connections are located near the compressor and are shown on the specific unit certified drawings Models WSC and WDC 050 chillers have refrigerant cooled oil coolers and require no cooling water connection WDC 063 079 087 100 and 126 dual compressor chillers are equipped as above but the water piping for the two oil coolers is factory piped to a common inlet and outlet connection Field water piping to the inlet and outlet connections must be installed according to good piping practices and should include stop valves to isolate the cooler for servicing A 1 minimum cleanable filter 40 mesh maximum and drain valve or plug should also be field installed The water supply for the oil cooler should be from the chilled water circuit or from an independent source such as city water When using chilled water it is important that the water pressure drop across the evaporator is greater than the pressure drop across the oil cooler or insufficient oil cooler flow will result If the pressure drop across the evaporator is less than the oil cooler the oil cooler must be piped across the chilled water pump provided that its pressure drop is sufficient The water flow through the oil cooler will be adjusted by the unit s regulating valve so that the temperature of oil supplied to the compressor bearings leaving the oil cooler is between 80 F and 110 F 27 C and 43 C Compressors using
78. he responsibility of the owner with the following exceptions A The manufacturer shall provide the first year scheduled oil and filter change if required B The manufacturer shall provide first year purge unit maintenance if required Product Manual PM WSC WDC 2 77 78 PART 2 PRODUCTS 2 1 ACCEPTABLE MANUFACTURERS A B McQuay International Approved Equal 2 2 UNIT DESCRIPTION Provide and install as shown on the plans a factory assembled charged and run tested water cooled packaged chiller Each unit shall be complete with two single stage hermetic centrifugal compressors each having independent lubrication and control systems isolation valves and starters The evaporator condenser and refrigerant control device of each unit shall be common to the compressors The chiller unit shall be capable of running on one compressor with the other compressor or any of its auxiliaries removed 2 3 DESIGN REQUIREMENTS A General Provide a complete water cooled dual hermetic compressor centrifugal water chiller as specified herein Machine shall be provided according to standards Section 1 2 In general unit shall consist of two compressors refrigerant condenser and evaporator two lubrication systems two starters and two control systems Note Chillers shall be charged with a chlorine free refrigerant such as HFC 134a not subject to the phase out of the Montreal Protocol and the U S Clean Air Act Performance Refer to schedu
79. ing water from the evaporator or condenser without draining the complete system CAUTION Freeze Notice The evaporator and condenser are not self draining Both must be blown out to completely remove water The condenser heads must be removed to do this Include thermometers and pressure gauges at the chiller inlet and outlet connections and air vents at the high points of piping The water heads can be interchanged end for end allowing water connections to be made at either end of the unit Use new head gaskets when interchanging water heads When water pump noise is objectionable use rubber isolation sections at both the inlet and outlet of the pump Vibration eliminator sections in the condenser inlet and outlet water lines are not normally required Where noise and vibration are critical and the unit is mounted on spring isolators flexible piping and conduit connections are necessary If not factory installed A flow switch or pressure differential switch must be installed in the leaving chilled water line in accordance with the flow switch manufacturer s instructions Filtering and Treatment Owners and operators should be aware that if the unit is operating with a cooling tower cleaning and flushing the cooling tower is required Make sure tower blow down or bleed off is operating Atmospheric air contains many contaminants which increases the need for water treatment The use of untreated water will result in corrosion erosion
80. ingle conduit would permit limited by dimensions of motor terminal box two or more conduits may be used Where multiple conduits are used all three phases must be balanced in each conduit Failure to balance each conduit will result in excessive heating of the conductors and unbalanced voltage An interposing relay may be required on remote mounted starter applications when the length of the conductors run between the chiller and starter is excessive Note On WDC dual compressor units dual power leads are standard requiring separate power leads properly sized and protected to each compressor starter or VFD Separate disconnects must be used Typical Field Connection Diagram WSC Unit MICROTECH CONTROL CHILLED BOX TERMINALS MICROTECH CONTROL WATER TISVAC BOX TERMINALS 3 PUMP STARTERS NOTE 12 15V Q4V uade 4 7 ICE TEMPLIFIER COOLING x SWITCH TOWER FOURTH 45 be db do g STAGE Le u 2 B u D B STARTER 44 e LINE NOTE 2 COOLING TOWER 5A 5A THIRD STAGE vs Ei STARTER CPte o L1 CP2 0 IU COMPRESSOR 25 urs MOTOR COOLING STARTER TOWER NOTE 1 C z1 SECOND NOTE 6 NOTE 6 2 22 STAGE SWITCH SWITCH
81. ion is available on 087 only 2 See notes on page 34 2 2 PASS PASS ESEJ oo eo o oo Ww Be EM a Bs Oa Da d o 1041 1092 40 1016 1041 43 1092 1041 46 1168 O cle clo wo yla yla yla pla a vw 2 olL alg n2 j2 A ali m 2 rw o LID PID Nio Pla Dios Pla Njo No ine q 2e wo SE g o o k wo 111 45 1173 B a m N M e N k k wo i a gm o N M e N wi e Do E a Sp O o ET wo i hv o M e hs oo Z 49 41 uzas aom 52 44 gs rte e 52 44 gs rte e aaa az 10 1422 1219 58 50 56 48 58 aso nere 12 12 12 Oa de g do E o On O 5 k wo pe 10 M O S w no 2 e _ u NENE To oo E xo c eo 9 KIS RA DAS a Ma k wo 50 3 66 1879 1676 APR 2032 1829 N N e o o A e o 9 q q 9 3683 Product Manual PM WSC WDC 2 CONNECTIONS VESSEL CODE EVAP COND E3012 C3012 4445 E3612 C3012 E3612 C3612 4445 E4212 C3612 E4212 C4212 4445 E4812 C4212 175 E4812 C4812 4597 4445 Note 1 2 3 Figure 12 WSC 100 126 600 to 1300 tons 1 1
82. kW so 88 90 89 se 39 Mackw es 263 204 263 263 es 36 933 Looked Rotor Amps 4753 2718 2949 2669 2778 2376 Td 06310087 Power Factor O MaxkW 87 se s se ws 8 7 41 875 06310087 Power Factor O MaxkW 0 85 90 88 we so so 90 89 89 Mackw 32 ss ses 35 ses 95 o 7 47 417 Locked Rotor Amps 5839 3885 3030 3196 3331 258 o 0650067 Power Factor R a jos 89 ja jo jo E Makw ars o o 374 a au 49 479 7 Looked Rotor Amps 6238 4632 3732 3937 409 3138 7 063 to 087 Power Factor G MaxkW so e s us ws 59 7 Do ww pp JO pp aw as eo sm 50 480 LokedRotrAmps o o o aa as e 063 to 087 Power Factor 6 MaxkW o o pp es so ps 99 En MSN epus pepper EA 52 500 Looked RotorAmps ar onto 12e Poner Faso aaa YAA Continued on next page 50 Product Manual PM WSC WDC 2 Compressor Motor Data 50 Hz continued Matar Boda Nominal SHp Voltage Code E v F G k H 6 j J 8 9 53 500 L MaxkwW 389 390 38 389 388 394 100 to 126 Locked Rotor Amps 4655 3752 3958 4113 3547 8375 89 o9 39 as 90 J o 9f 57 542 424 424 424 s24 s24 saa o
83. kW ton COP e Pressure drops ft of water kPa e Integrated Part Load Value IPLV or Non Standard Part Load Value NPLV As part of the ARI certification program ARI has the McQuay computer selection program used to select and rate chillers The certified computer program version number and issue date for all manufacturers is listed in the ARI Directory of Certified Applied Air Conditioning Products available on www ari org Product Manual PM WSC WDC 2 27 ARI Standard 550 590 98 for Centrifugal or Screw Water Chilling Packages and associated manuals define certification and testing procedures and tolerances of all units that fall within the application rating conditions Leaving chilled water temperature eee 40 F to 48 F Entering condenser water temperature 60 F to 95 F Rating outside the range of the certification program may be listed or published but must include a statement describing such The standard rating conditions are Leaving chilled water temperature sss 44 F Evaporator waterside field fouling allowance 0 0001 Chilled water flow rate 2 4 gpm ton Entering condenser water temperature 85 F Condenser waterside field fouling allowance 0 00025 Condenser water flow rate sess 3 0 gpm ton IPLV NPLV Defined Part load performance can be presented in terms of Integrated Pa
84. l Panel terminal connectors will accommodate up to number 10 AWG wire Larger conductors will require an intermediate junction box Product Manual PM WSC WDC 2 53 Motor Starters 54 McQuay has a wide variety of starter types and options to fit virtually all applications The specifics of the final selection of size and enclosure are covered in the product manual PM Starters Please consult the local McQuay sales office or this manual for starter details This section contains a general overview only Mounting Options Factory furnished factory mounted on vessel stacks larger than E3616 C3016 the starters are shipped loose with cable kits and mounting brackets for field installation on the units by others Factory furnished floor mounted drop shipped to job site for setting and wiring by others Furnished by others must meet McQuay Starter Specification and be approved by McQuay Engineering Low Voltage Starters 200 through 600 volts Standard equipment Low voltage starters are continuous duty AC magnetic type with air break contactors Enclosures are NEMA 1A gasketed door with top cable entry bottom entry optional Main control relays are redundant with coils in parallel and contacts in series Included are overload protection phase failure and reversal protection stall protection undervoltage protection and control transformer Wye Delta closed transition This starter sometimes called Star Delta is
85. l be insulated with UL recognized 3 4 inch closed cell insulation All joints and seams shall be carefully sealed to form a vapor barrier 10 Provide water pressure differential switches on each vessel to prevent unit operation with no flow furnished installed and wired by the contractor D Prime Mover Squirrel cage induction motor of the hermetic type of sufficient size to efficiently fulfill compressor horsepower requirements Motor shall be liquid refrigerant cooled with internal thermal overload protection devices embedded in the winding of each phase Motor shall be compatible with the starting method specified hereinafter If the Contractor chooses to provided an open drive motor or compressor verify in the submittal that the scheduled chiller room ventilation system will accommodate the additional heat and maintain the equipment room at design indoor temperature based on 95 F outdoor ambient ventilation air available If additional cooling is required manufacturer shall be responsible for the installation wiring and controls of a cooling system Chiller selection shall compensate for tons and efficiency loss to make certain the owner is not penalized E Motor Starters 1 The main motor starters are to be factory mounted and fully wired to the chiller components and factory tested during the run test of the unit Or The main motor starters are to be furnished by the chiller manufacturer and shipped loose for floor mounting a
86. l sB lc Xx Y 12 0 E Fr G PASS PASS E4220 C4220 6909 6772 6909 2591 2343 2991 1165 921 6269 6193 2343 2140 320 315 320 102 92 136 44 37 295 292 92 FARES E4224 C4224 8128 7991 8128 2591 2343 3457 1121 946 7487 7412 2343 2140 14 16 2140 276 271 276 111 104 118 49 43 247 244 104 96 324 319 324 111 104 138 47 45 295 292 104 96 Note See notes on page 34 Product Manual PM WSC WDC 2 43 44 Marine Water Boxes WSC Marine water boxes are an available option on all evaporator and condenser sizes Epoxy coating of the water boxes and clad tube sheets are available for extreme duty applications EVAP 1 PASS EVAP 2 PASS EVAP 3 PASS OPPOSTE END OF U UNIT EE Lie l ccc Es REPRESENTATIVE OF RIGHT HAND VIEW SHOWN REFLECTS A R H INLET OR WITH VICTAULIC CONNECTIONS A LH OUTLET MIRROR IMAGE OF ABOVE LEFT HAND CONNECTION IS MIRROR IMAGE OF ABOVE REFLECTS A L H INLET OR R H OUTLET NOTE ADD 500 INCH FOR FLANGED CONNECTION REAR FACING ONLY REAR FACING ONLY REAR FACING ONLY COND 1 PASS COND 2 PASS COND 3 PASS THIS HEAD IS ON THE yA OPPOSITE END OF UNIT 1 1 1 1 bee L EEl BBB DDD AAA t ecc REPRESENTATIVE OF RIGHT HAND VIEW SHOWN REFLECTS A R H INLET FOR WITH VICTAULIC CONNECTIONS A L H INLET MIRROR A
87. le on the drawings The chiller shall be capable of stable operation to five percent of full load with standard ARI entering condensing water relief without hot gas bypass Acoustics Sound pressure levels for the unit shall not exceed the following specified levels Provide the necessary acoustic treatment to chiller as required Sound data shall be measured according to ARI Standard 575 87 Data shall be in dB Data shall be the highest levels recorded at all load points Octave Band 63 125 250 500 1000 2000 4000 8000 dBa 2 4 CHILLER COMPONENTS A Compressors 1 Unit shall have two single stage hermetic centrifugal compressors Casing design shall ensure major wearing parts main bearings and thrust bearings are accessible for maintenance and replacement Lubrication system shall protect machine during coast down resulting from a loss of power 2 Impeller shall be statically and dynamically balanced The compressor shall be vibration tested and not exceed 0 14 IPS de Movable inlet guide vanes actuated by an internal oil pressure driven piston shall accomplish unloading Compressors using an unloading system that requires penetrations of the compressor housing for linkages that must be lubricated and adjusted are acceptable provided the manufacturer provides a five year inspection agreement consisting of semi annual inspection lubrication and annual changeout of compressor seals A statement of inclusion must accompany any quotations
88. led factory charged and factory run tested water cooled packaged chiller Each unit shall be complete with a single stage hermetic centrifugal compressor with lubrication and control system starter evaporator condenser refrigerant control device and any other components necessary for a complete and operable chiller package 2 3 DESIGN REQUIREMENTS A General Provide a complete water cooled hermetic centrifugal compressor water chilling package as specified herein Machine shall be provided according to referenced standards Section 1 2 In general unit shall consist of a compressor condenser evaporator lubrication system starter and control system Note Chillers shall be charged with a chlorine free refrigerant such as HFC 134a not subject to phase out from the Montreal Protocol and the U S Clean Air Act Performance Refer to schedule on the drawings The chiller shall be capable of stable operation to ten percent of full load with standard ARI entering condensing water relief without the use of hot gas bypass Acoustics Sound pressure levels for the complete unit shall not exceed the following specified levels Provide the necessary acoustic treatment to chiller as required Sound data shall be measured according to ARI Standard 575 87 Data shall be in dB Data shall be the highest levels recorded at all load points Octave Band 63 125 250 500 1000 2000 4000 8000 dBa Product Manual PM WSC WDC 2 69 70 2 4 CHILLER COMP
89. ller trip depending on load and operating condition In this extended ride through the drive uses the energy generated by the rotating fan as a power source for all electronic circuits d RS232 Port and Windows based software for Configuration Control and Monitoring e Anisolated 0 20mA 4 20mA or 0 4 0 8 0 10 volt analog speed input follower f Anisolated 0 10 V or 4 20 mA output signal proportional to speed or load Product Manual PM WSC WDC 2 g Standard I O Expansion Interface Card with the following features PI regulator for set point control Four Isolated 24 VDC programmable digital inputs An additional analog input for speed feedback to PI regulator One Frequency Input 0 to 200 Hz for digital control of current limit Four programmable Isolated Digital Outputs 24 VDC rated One Form A output relay rated at 250 VAC or 24 VDC Two NO NC programmable output relays rated at 250 VAC or 24 VDC 9 The VFD includes the following protective circuits and features VFD Models Motor current exceeds 200 of drive continuous current rating Output phase to phase short circuit condition Total ground fault under any operating condition High input line voltage Low input line voltage Loss of input or output phase External fault This protective circuit shall permit wiring of remote N C safety contact to shut down the drive Metal Oxide Varistors for surge suppression are provided at the VFD input terminals VFD
90. m this example Lower Installed Costs The redundancy feature pays off in lower installed costs An example of how to incorporate dual compressor chillers into a system requiring redundancy Job requirement 1 200 tons 4200 kW 50 Backup Single Compressor Method Dual Compressor Method 2 600 ton 2100 kW On Line Units 2 750 ton 2100 kW Units with 1 600 2100 kW ton Standby Unit 1 200 4200 kW Standby tons 3 1 800 ton 6300 kW Installed Capacity 2 E 1500 ton 5250 kW Installed Capacity One 750 ton 2100 kW chiller running on two compressors for 750 tons 2100 kW plus one 750 ton 2100 kW chiller running on one compressor for 60 of 750 tons 2100 kW 450 tons 1575 kW for a total of 1200 tons 4200 kW on 3 of 4 compressors The elimination of the extra pumps valves piping controls rigging and floor space can result in as much as a 3596 reduction in the installation cost for a chiller plant plus the savings on the chillers themselves Bolt Together Construction The Replacement Market Advantage e Put 20 or more tons in the same footprint e Add dual compressor redundancy e Greatly reduce chiller energy consumption e Install an unregulated refrigerant e Opens many options for multiple chiller plants Product Manual PM WSC WDC 2 WDC Chiller Controls Each model WDC dual compressor chiller comes complete with two compressor dedicated factory mounted and wired MicroTech control panels I
91. mperature at design ambient air temperatures cooling tower fans must continue to operate at 100 capacity at low wet bulb temperatures As chillers are selected for lower kW per ton the cooling tower fan motor power becomes a higher percentage of the peak load chiller power On the other hand the low condenser water temperatures may be 20 easy to achieve in mild climates with low wet bulb Y temperatures 10 12 14 16 18 20 22 24 80 70 60 50 i gt 30 PERCENT PART LOAD F ADDITION TO LEAVING CHILLED WATER TEMP Even with tower fan control some form of water flow NOTE If a reasonable operating minimum cannot be calculated assume 10 control such as tower bypass is recommended Figure 20 and Figure 21 illustrate two temperature actuated tower bypass arrangements The Cold Weather scheme provides better startup under cold ambient air temperature conditions The check valve may be required to prevent air at the pump inlet Figure 19 Tower Bypass Valve Pressure Actuated Cooling Tower Product Manual PM WSC WDC 2 Figure 20 Tower Bypass Mild Weather Operation TOWER SUMP ci E poete gm n COND Figure 21 Tower Bypass Cold Weather Operation TOWER t X Oil Coolers McQuay centrifugal chillers sizes 063 through 126 have a factory mounted water cooled oil cooler temperature controlled water re
92. mpressor verify in the submittal that the scheduled chiller room ventilation system will accommodate the additional heat and maintain the equipment room at design indoor temperature based on 95 F outdoor ambient ventilation air available If additional cooling is required manufacturer shall be responsible for the installation wiring and controls of a cooling system Chiller selection shall compensate for tonnage and efficiency loss to make certain the owner is not penalized E Motor Starter 1 The main motor starter is to be factory mounted and fully wired to the chiller components and factory tested during the run test of the unit Or The main motor starter is to be furnished by the chiller manufacturer and shipped loose for floor mounting and field wiring to the chiller package It shall be free standing with NEMA 1 enclosure designed for top entry and bottom exit and with front access 2 For open drive air cooled motors the chiller manufacturer shall be responsible for providing the cooling of the refrigeration machinery room The sensible cooling Product Manual PM WSC WDC 2 71 load shall be based on the total heat rejection to the atmosphere from the refrigeration units 3 For open motor units an oil reservoir shall collect any oil and refrigerant that leaks past the seal A float device shall be provided to open when the reservoir is full directing the refrigerant oil mixture back into the compressor housing Manufact
93. n use today in centrifugal compressors Note that required compressor tip speeds are all within eight percent of each other All McQuay centrifugal chillers use refrigerant HFC 134a The machine design characteristics of this refrigerant and its Refrigerant HCFC HFC HCFC 123 134a 22 Condenser Press psig 100 F 124 1 195 9 Evaporator Press psig 40 F 18 1 35 0 68 5 Inches of Mercury Vacuum Ozone Depletion Potential ODP 0 02 0 00 0 05 predecessor R 12 such as small moving parts low mass low inertia quick spin up and coast down and simplicity of design have continuously proven themselves since the first chiller was introduced in 1962 The small and lightweight rotating parts lend themselves to easy servicing of the compressor and its associated parts and piping Figure 3 HFC 134a Impeller Compared to HCFC 123 Impeller Left Impeller from a McQuay single stage 300 ton 1050 kW compressor diameter 6 3 in 16 cm weight z 3 0 Ib 1 4 kg Right One of three impellers from a 300 ton HCFC 123 compressor diameter 26 in 66 cm weight 27 Ib 12 2 kg Compact Design Small Footprint Cuts Installation Costs At comparable cooling capacities HFC 134a requires less than 3 2 cfm 1 5 l sec per ton of refrigeration to be circulated by the compressor HCFC 123 requires over 18 0 cfm 8 5 l sec per ton The substantial increase in refrigerant volume requires significantly larger suction pipin
94. nd field wiring to the chiller package They shall be free standing with NEMA 1 enclosure designed for top entry and bottom exit and with front access 2 For air cooled motors the chiller manufacturer shall be responsible for providing the cooling of the refrigeration machinery room The sensible cooling load shall be based on the total heat rejection to the atmosphere from tow refrigeration units 3 For open motor unit an oil reservoir shall collect any oil and refrigerant that leaks past the seal A float device shall be provided to open when the reservoir is full directing the refrigerant oil mixture back into the compressor housing Manufacturer shall warrant the shaft seal reservoir and float valve system against Product Manual PM WSC WDC 2 79 80 leakage of oil and refrigerant to the outside of the refrigerating unit for a period of 5 years from the initial start up including parts and labor to replace a defective seal and any refrigerant required to trim the charge original specifications The starters must comply with Section 1 2 as required AII controllers are to be continuous duty AC magnetic type constructed according to NEMA standards for Industrial Controls and Systems ICS and capable of carrying the specified current on a continuous basis The starters shall be Autotransformer The autotransformer starters shall be of the closed transition type and equipped with multiple taps for 80 65 50 and set up for the 65
95. ndividual control panels allow the monitoring of each compressor independently from the other Elapsed time number of starts percent RLA are all monitored separately by each MicroTech control panel Also individual compressor fault history setpoint control loading functions time of day starts etc can be controlled and monitored The lead lag load balance function is a standard feature of each MicroTech panel and therefore of the WDC chiller Smart scheduling by the lead lag load balance function assigns the compressor with the fewest starts as lead and will only start the lag compressor when proof of sufficient load has been established The lead lag function will stop the compressor with the most hours when the load decreases to single compressor range During two compressor operation the load balance function will equalize the load between each compressor providing optimum unit efficiency 25 or greater annual kWh savings over the range of 5 to 60 design tons The majority of comfort cooling systems operate at 60 or less of building design tons for most of the year A great number of those operating hours occur between 5046 and 6096 design cooling capacity For that reason the Model WDC chiller was designed to produce up to 60 unit capacity with a single operating compressor efficiently and reliably That performance is achieved by a combination of individual component features that include compressor design operating control do
96. ne The insulation used is UL recognized Card No E61978 It is 3 4 thick vinyl nitrate polymer having a K factor of 0 28 at 75 F The sheet insulation is fitted and cemented in place forming a vapor barrier then painted with a resilient epoxy finish that resists cracking The insulation complies to appropriate requirements or has been tested in accordance with the following HH 1 573 GSA FSS ASTM D 1149 ASTM C 177 ASTM C 534 ASTM D 1056 UL 94 5V ASTM C 355 Refrigerant side design pressure is 200 psi 1380 kPa on WSC units and 180 psi 1242 kPa on WDC units Water side is 150 psi 1034 kPa on both In the event insulation is to be field installed none of the cold surfaces identified above will be factory insulated Approximate total square footage of insulation surface required for individual packaged chillers is tabulated by evaporator code and may be found below Table 1 Evaporator Physical Data Evaporator wsc WDC Refrigerant Charge Evaporator Water Insulation Area ime e Nai AA Code lb kg Capacity gal L Sq Ft m Valvos E1809 La E 434 197 37 138 75 7 0 2734 1239 E1812 x 347 158 27 103 78 7 2 2370 1075 0 2 E2009 561 254 3a 164 E2012 6 1 3 3 E2209 54 206 3285 1488 E2212 45 170 90 8 2877 1305 8 E2212 90 j 555069 1 4 E2009 E2012 E2209 E2212 E2212 4200 1903 4410 1999 9 4745 2150 67 252 86 8 0 207 19 2
97. normally found on McQuay chillers R 12 R 22 R 134a R 410A and R 500 Table 6 Standard Equipment Equipment RRU134 RRU570 RRU 999 Reducing Fittings CE A 12 ft Tank Float Switch Cable X Connection Sizes Ye in Flare 1 Ya in Pipe 4 10 ft 1 10 ft 2 20 ftX i X Product Manual PM WSC WDC 2 33 34 Dimensions Chillers Figure 9 WSC 048 WSC 050 80 to 150 tons VESSEL CODE 134 E2209 C2009 3404 164 169 E2212 C2012 4299 4166 4293 9 Q Ron 3404 mw AN j Eoo Bajas i i 1 FACTORY MOUNTED EVAPORATOR STARTER i OPTIONAL J d E esp CONDENSER A a 55 3251 163 4140 128 3251 163 4140 128 3251 163 4140 129 3277 T LENGTH 1 amp 3 EVAP COND aem Loss HEAD CONN BOTH ENDS 134 3404 4293 3404 4293 3404 4293 3404 OVERALL HEIGHT 1803 1067 1803 1067 1803 1067 1803 1067 1803 1067 1803 1067 1803 1067 1803 1067 1397 787 1829 762 1397 787 1829 762 1397 787 1854 762 1397
98. nt control at low load conditions The liquid line shall have a moisture indicating sight glass T The evaporator and condenser shall be separate shells A single shell containing both vessel functions is not acceptable because of the possibility of internal leaks 8 Reseating type spring loaded pressure relief valves according to ASHRAE 15 safety code shall be furnished The evaporator shall be provided with single or multiple valves The condenser shall be provided with dual relief valves equipped with a transfer valve so one valve can be removed for testing or replacement without loss of refrigerant or removal of refrigerant from the vessel Rupture disks are not acceptable 9 The evaporator suction line and any other component or part of a component subject to condensing moisture shall be insulated with UL recognized 3 4 inch closed cell insulation All joints and seams shall be carefully sealed to form a vapor barrier 10 Provide factory mounted water pressure differential switches on each vessel to prevent unit operation with no flow D Prime Mover Squirrel cage induction motor of the hermetic type of sufficient size to efficiently fulfill compressor horsepower requirements Motor shall be liquid refrigerant cooled with internal thermal overload protection devices embedded in the winding of each phase Motor shall be compatible with the starting method specified hereinafter If the Contractor chooses to provided an open drive motor or co
99. o advanced that they have been given a new model designation WSC for single and WDC for dual compressor units Their new name the DISTINCTION SERIES was deemed highly appropriate Distinction is defined as Excellent in performance Recognition of superiority The fact of being different FEATURES Available with Variable Frequency Drive VFD Alternative refrigerant leadership Complete HFC 134a centrifugal chiller line Dual compressors available up to 2 700 tons 9500kW Two of all mechanical and electrical components New generation MicroTech Control Bolt together construction at tube sheets Pumpdown capability Entire charge can be stored in the condenser Small footprint Units performance tested in the factory to job conditions within established limits Over 30 years of product refinement and factory ISO Certification BENEFITS Provides superior efficiency in many applications Industry leading efficiency when teamed with Dual Compressor Chillers The confident choice for the future Positive pressure Environmentally safe Non toxic Lower annual energy cost than any single compressor chiller Dual compressor reliability Small footprint A complete chiller plant controller Open protocol Loaded with customer benefits See detailed specification Easy disassembly and re assembly at the job site for those difficult retrofit installations Eliminates the need for a separate pumpout vessel in most
100. ock with fuses drawout three pole vacuum break contactor control transformer control circuit primary and secondary fuse block current transformers and phase failure and reversal relay Across the line starter Across the line starters are very simple and consist of a primary contactor that allows locked rotor amps to reach the motor when energized These starters are low cost provide the highest starting torque require the least maintenance and can be used with any standard motor However they have the highest starting inrush current Autotransformer starter In addition to the standard equipment listed above are drawout magnetic three pole vacuum break shorting assembly drawout three pole vacuum break starting contactor and starting auto transformer The autotransformer starter operation was discussed in the low voltage starter section As with low voltage starters the 65 tap is used for centrifugal compressors providing 42 starting torque with 45 inrush current The time for the starter to transition from reduced current to full voltage as the motor reaches the proper speed is critical to get a relatively shock free transition Once the starting sequence begins the motor is not disconnected from the line which prevents a second inrush spike from occurring Autotransformer starters are a good choice because of their efficiency and flexibility All power taken from the line is transmitted to the motor except for some transformer l
101. ompressor speed at low load low head conditions Product Manual PM WSC WDC 2 Extended Motor Life McQuay s modern compact compressor design equates to many operating advantages that improve its overall reliability and durability One such advantage is prolonged motor life A motor draws locked rotor current until it reaches break away torque at approximately 8096 of its running speed While drawing locked rotor current the stresses on the motor are over six times that of full load The McQuay compressors absolutely minimize this stress through the unique gear drive and light weight drive train that allows a 500 ton 1750 kW compressor to reach running speed in less than three seconds The owner benefits from a longer motor life Safe Compressor Coast Down Another advantage is the short coast down time Under normal operating conditions the electric driven oil pump continues to feed oil to the bearings during coast down However if a power failure occurs the pump is unable to provide positive coast down lubrication With McQuay s design coast down takes less than 15 seconds and this short time allows an internal reservoir to provide positive oil flow to the bearings Figure 1 McQuay s new million dollar compressor test stand with state of the art data acquisition provides comprehensive information on new compressor designs Single Stage Simplicity Savings Compressor efficiency is NOT a function of multiple impellers Maintenance of optim
102. on of noncondensable gases that are known as robbers of efficiency These foreign gases compete with refrigerant for heat exchange surface and can reduce efficiency by as much as 14 at full load Positive pressure eliminates oil degradation due to non condensables Contaminated oil will produce acids that attack and breakdown motor insulation and copper plate shafts and bearings The contaminant free extended life lubricant used in McQuay chillers offers a means to gauge the health of your machine over the years Preventative action should be taken through diagnostic analysis methods available for synthetic lubricants Product Manual PM WSC WDC 2 No purge system to e Attack the ozone e Escalate operating costs e Increase annual maintenance Chiller systems utilizing negative pressure refrigerants are subject to the continuous introduction of equipment room moisture and non condensables into the refrigerant circuit Bolted surfaces vane operator linkage outlets motor terminals control tubing connections and casing porosity all provide points of entry for the introduction of these foreign gases into the circuit This can be especially destructive in maritime locations where salt laden air is present These non condensables must be isolated collected and purged continuously from the equipment To prolong the useful life of low pressure refrigerant systems an automatic purge unit is required as a standard accessory A variety of type
103. ontrol malfunction occurs artificially elevating the compressor head a rotating stall or surge condition can occur Under normal operating conditions all WSC chillers will operate to 10 capacity without surge and WDC dual compressor chillers to 5 capacity without surge For abnormal conditions McQuay compressor designers have developed a protective control system that senses the occurrence of a surge and stops the compressor before any damage is sustained This protection called SurgeGard is provided as a standard on all McQuay centrifugal compressors Quiet stable capacity from 10 to 100 without hot gas bypass Compressor capacity on McQuay chillers is maximized at full load and modulated to 10 load by interlocked inlet guide vanes and the movable discharge geometry This seemingly esoteric and unimportant design detail like many other McQuay innovations has real owner benefits Compressors that do not unload this well and most don t waste energy at low load conditions by unnecessary cycling or use of hot gas bypass No leakage at the capacity control mechanism An oil pressure operated guide vane activating piston is internally mounted and powered to eliminate external linkage and seals The vanes are positioned in response to variation in leaving chiller water temperature A built in compensating control allows automatic override of normal operation to close the vanes for low suction pressure or current limiting duty Pumpdown P
104. or 600 HP 16 000 BTU Hr for 350 HP and 20 000 BTU Hr for 450 HP The cooling circuit maintains water temperature between 60 F and 104 F 15 C to 40 C The VFD and options are cUL 508 listed The drive and options are designed to comply with the applicable requirement of the latest standards of ANSI NEMA National Electric Code NEC NFPA 70 IEEE 519 1992 FCC Part 15 Subpart J CE 96 They are functionally tested under motor load During this load test the VFD is monitored for correct phase current phase voltages and motor speed Correct Current Limit operation is verified by simulating a motor overload Verification of proper factory presets by scrolling through all parameters is performed to ensure proper microprocessor settings The computer port also verifies that the proper factory settings are loaded correctly in the drive The VED has the following basic features a An electronic overload circuit designed to protect an A C motor operated by the VFD output from extended overload operation on an inverse time basis This Electronic overload is UL and NEC recognized as adequate motor protection No additional hardware such as motor overload relays or motor thermostats are required b AnLED display that digitally indicates Frequency output Voltage output Current output Motor RPM Input kW Elapsed Time Time Stamped Fault Indication DC Bus Volts c The capability of riding though power dips up to 10 seconds without a contro
105. osses during starting They are not smooth starting they may shock machinery if the timing cycle for the motor and starter are not closely matched Primary reactor starter In addition to the standard equipment listed above drawout magnetic three pole vacuum break shorting assembly and three phase starting reactor factory set at 6596 tap These starters are similar in operation to the autotransformer however they provide 42 starting torque with 65 inrush of locked rotor current Additional Options for Medium Voltage Starters Certifications and Approvals e UL certification for full voltage starters e UL certification for reduced voltage starters e CSA certification for full voltage starters e CSA certification for reduced voltage starters Product Manual PM WSC WDC 2 55 56 Options for Low and Medium Voltage Starters Metering devices Ammeters voltmeters Deluxe motor protection system The deluxe motor protection system is the IQ DP 4000 which includes an ammeter voltmeter watt hour meter wattmeter power factor meter frequency meter undervoltage protection overvoltage protection phase loss phase reversal and phase unbalance in a single device Protection device options Overvoltage relay and lightning arrestors Pilot devices Indicating lights additional electrical interlocks and control relays NEMA modifications e NEMA 1A adds a gasket to the starter door of NEMA construction option on medium voltage sta
106. ower Factor Max kw 89 88 89 89 87 88 89 89 8 amp 7 88 15 150 Mexkw 124 128 124 124 124 124 124 124 128 128 ff 050 Locked Rotor Amps 1813 1886 1469 1536 1603 890 735 768 801 610 Power Factor MaxkW 87 86 88 87 86 88 88 87 se 67 1 i8 185 Mexkw 145 145 146 145 145 145 146 145 145 145 063 to 087 Locked Rotor Amps 2850 2975 2204 2402 2517 1617 1147 1201 1259 1022 T T Power Factor O Max kw 89 87 90 89 87 87 90 89 87 88 908 how 1 1 114 pop ap a gg e 0631005 Locked Rotor amps T T T T 1 Jf 1 p asmpste 23 e J Power Factor E MxkW T T T J T 9 ss 80 8 20 200 Maduro us as as og a 15e dee pe q 063 to 087 Locked Rotor Amps 2833 2954 2472 2591 2712 1516 1289 1352 1206 1020 T T Power Factor O Max kW 91 90 91 90 90 91 91 90 90 90 21 210 CC Mw TIT L8 38 38 T1387 063 to 087 Locked Rotor Amps T T T TJT T T T j ws 23 94 j Power Factor MaxkW ___ T J 1 pee e 83 8 23 230 DO MexkW 180 180 181 180 180 180 38i 180 i80 i 7 06319 087 Locked Rotor Amps 3885 4063 2064 3112 3238 1849 1482 1556 1619 1244
107. ower generation Bottom line equipment operators should keep equipment leak free and operate as efficiently as possible Since Power Plant Emission 98 annualized energy consumption think power plant output is a basis for measurement McQuay s superior part load efficiencies mean lower overall power plant CO emissions and lower TEWI e True System Efficiency KW ton or COP deals with the total power consumption annual kWh of a chiller system including auxiliaries such as pumps purge units Pre Vac heaters and fans of great importance in determining facility energy cost and ultimate power plant CO emissions e Toxicity and Flammability Rating per 1997 ASHRAE Fundamentals Handbook e HFC 134a gt A 1 e HCFC 123 gt B 1 Where A Toxicity not identified B Evidence of toxicity identified 1 No flame propagation in air at 65 F 50 rh and one atmosphere pressure A certain future for HFC 134a The Clean Air Act of November 1990 allows the EPA to accelerate the phase out schedule of Class I CFC and Class II HCFC refrigerants if it deems it necessary This leaves the future of HCFCs which includes HCFC 22 and HCFC 123 uncertain HFC 134a will not be regulated or phased out by the Clean Air Act or the Montreal Protocol The commercial air conditioning home appliance and automotive industries are just a few of the many markets that are using HFC 134a now and for years into the future This large market demand for HFC 134a tr
108. pressor Chillers Dual Compressor with VFD Variable Speed Water Flow Tower Economizer Cycle NOTE ARI limit for certification on 60 Hz service is 2 000 tons McQuay dual compressor chillers with or without VFD are available up to 2 700 tons The chart below illustrates the relative IPLV efficiencies of various McQuay options for a 500 ton selection The chiller cost increases as the efficiency improves Industry Leading Efficiencies KW Ton 6 IPLV WSC WDC WSC w VFD WDC w VFD Notes WSC Single Compressor Centrifugal Chiller WDC Dual Compressor Centrifugal Chiller VFD Variable Frequency Drive The IPLV values are ARI Certified Ratings based on ARI Standard 550 590 1998 Standard for Water Chilling Packages Using the Vapor Compression Cycle Full load at 44 F chilled water temperature with 2 4 gpm ton 85 F condenser water temperatures with 3 gpm ton Part load points of 75 50 and 25 employing condenser water temperature relief per the standard Be wary of competitive efficiency claims at other than standard conditions Product Manual PM WSC WDC 2 Dual Compressor Design Dual Compressor Chillers Offer Better Efficiency Lower Installed Costs Less Floor Space and Higher Reliability Than Single Compressor Designs AND NOW with Variable Frequency Drive VFD for Industry Leading IPLV
109. r demand limiting of either compressor Lead lag can be selected as manual or automatic In automatic the compressor with the least starts will start first and the compressor with the most hours will stop first Load balance equalizes the load between the two compressors providing optimum efficiency and preventing short cycling of the lag compressor Figure 5 Multi Panel Control Two Unit Model WSC Control Dual Compressor Model WDC Optional Open Protocol 4 20mA DC Signal For Reset of Chilled Water I I Panel Reset of Chilled Water I I I Both Units 4 20mA DC Signal a 4 20mA DC Signal SI Optional Open Protocol Panel Demand Limiting Both Both Units Both Compressors Demand Limiting 4 20mA DC Signal For Both Compressors Optional McQuay PC Optional McQuay PC Software for MS DOS Software for MS DOS N L PC DOS Computer Di PC DOS Computer Optional Factory Installed Phone Modem OptionalFactory Installed Phone Modem Product Manual PM WSC WDC 2 Three or More Units In the past it has been difficult to control multiple machines for optimum operating economy and comfort MicroTech Chiller System Controllers CSC allow coordinated control of multiple machines from load balancing and sequencing to control of the cooling tower and water pumps All this is accomplished via twisted pair communications between the Chiller System Control panel and the chiller
110. r is proportional to the square of the tip speed Rotational speed is only part of the equation along with impeller diameter In designing a centrifugal compressor two fundamental parameters impeller diameter and impeller tip speed must be determined Impeller diameter is determined by the required volume flow rate supplied to the inlet of the impeller Refrigerants which operate at a negative pressure such as HCFC 123 have high cfm ton m kW flow rates and require larger diameter impellers and refrigerant lines to keep pressure drop to reasonable levels Pressure drop reduces refrigeration capacity and increases input power Systems with refrigerants which operate at a positive pressure such as HFC 134a have smaller impellers and gas lines since these refrigerants require lower gas flow rates HCFC 123 requires approximately six times the gas flow rate in cfm per ton than HFC 134a At ARI standard conditions 18 1 cfm 8 54 l sec of HCFC 123 is required per ton of refrigeration Contrast this to HFC 134a which requires 3 2 cfm 1 5 l sec per ton This means that for a given capacity the cross sectional area of the impeller inlet wheel eye as well as the suction and discharge lines will be six times larger for HCFC 123 than for HFC 134a at equivalent pressure drops The wheel eye diameter is the major factor in determining the overall impeller diameter and geometry In addition to wheel eye diameter designers of centrifugal equipment must consid
111. rant plate heat exchanger and single or dual 5 Ls aa micron oil filters internal to the compressor A All bearing surfaces are pressure lubricated Drive gears are operated in a controlled Oil Cooler lubrication mist atmosphere that efficiently The unique lubrication cools and lubricates them system provides forced feed lubrication to all Lubricant is made available under pressure bearing surfaces as well as from the compressor oil filter to the unit full coast down protection capacity control system and is used to Ey position the inlet guide vanes in response to Oil Sump Pump changes in leaving chiller water temperature Should a power failure occur an emergency oil reservoir guarantees adequate lubrication flow under pressure and prevents damage that could occur during the spin down period with the oil pump stopped Since the McQuay chillers are positive pressure there is no need to change lubricant or filter on a regular basis An annual oil check is recommended to evaluate the lubricant condition Product Manual PM WSC WDC 2 13 14 SurgeGard Protects the Compressor from Surge Damage As centrifugal compressors operate at part load the volume of refrigerant gas entering the impeller is reduced At the reduced flow the impeller s capacity to develop the peak load head is also reduced When inadequate maintenance of condenser tube cleanliness or a cooling tower or c
112. rt Load Value IPLV which is based on ARI standard rating conditions listed above or Non Standard Part Load Values NPLV which is based on specified or job site conditions IPLV and NPLV are based on the following equation from ARI 550 590 IPLV or l or 0 01A 0 42B 0 45C 0 12D APEN 0 01 i 0 42 V 0 45 0 12 A B C D Where A kW ton at 100 Where A COP at 100 B kW ton at 75 B COPat 75 C kW ton at 50 C COPat50 D kW ton at 25 D COP at 25 Weighting The percent of annual hours of operation are weighted as follows 100 Load at 1 75 Load at 42 50 Load at 4596 25 Load at 12 Tolerances The ARI test tolerance per ARI Standard 550 590 98 for capacity tons power input per ton KW ton and heat balance is 96 Tolerance 10 5 0 07 x96 FL 1500 DTFLx FL Where FL Full Load DTFL Chilled Water Delta T at Full Load Product Manual PM WSC WDC 2 Chiller Identification To provide a wide range of components to match job requirements of capacity efficiency and competitive initial cost McQuay WSC and WDC centrifugal chillers are selected by computer and identified by their components The variations of compressor impeller gear ratio evaporator and condenser tube surface and configuration provide over 1 000 000 combinations of standard components within the range of 80 to 2 700 tons It is impractical to catalog all of these combinations Therefore computer selection for sp
113. rters Wiring of free standing starter or VFD must be done in accordance with NEC and connection to compressor motor terminals must be made with copper wire and copper lugs only For optional sensor wiring see unit control diagram Terminals AH1 through AH6 It is recommended that DC wires be run separately from 115 VAC wiring A customer furnished 24 volt alarm relay coil may be connected between terminals 50 and 68 of the control panel The alarm is operator programmable Maximum rating of the alarm relay coil is 25 VA Remote On Off control unit can be accomplished by installing a set of dry contacts between terminals 9 and 64 If an additional point of On Off control is required remove jumper from terminals 64 and 65 and install the additional set of dry contacts Evaporator and condenser paddle type flow switches or pressure differential switches are required and must be wired as shown Field supplied pressure differential switches must be installed across the vessel and not the pump A 115 VAC oil cooler solenoid OC1 or a two solenoid 24 VAC oil cooler motorized valve OC1 OC2 are two options required on some models Refer to the installation manual and wire as shown Optional customer supplied 115 VAC 25VA maximum coil rated chilled water pump relay CHWR 1 and 2 may be wired as shown This option will cycle the chilled water pump in response to building load The condenser water pump must cycle with the unit A customer supplied 115VAC 25
114. rters standard on low voltage starters e NEMA3R Rain resistant construction e NEMA4 Rain tight construction e NEMA 4 4X with stainless steel construction for both non combustion and combustion use e NEMA 12 Dust tight construction Low voltage starters only Product Manual PM WSC WDC 2 Variable Frequency Drives WSC and WDC single and dual compressor chillers can be equipped with Variable Frequency Drive VFD A VFD modulates the compressor speed in response to load and evaporator and condenser pressures as sensed by the microprocessor Despite the small power penalty attributed to the VFD the chiller can achieve outstanding part load efficiency VFD s really prove their worth when there is reduced load combined with low compressor lift lower condenser water temperatures dominating the operating hours The drives provide two important operating benefits VFD for Efficiency The traditional method of controlling centrifugal compressor capacity is by inlet guide vanes The vanes are triangular in form and have an airflow shape in cross section As the microprocessor control detects an increase in leaving chilled water temperature indicating a decrease in load the guide vanes are given a signal to start to close This throttles the inlet gas flow and also changes its entry angle into the impeller reducing compressor capacity Throttling suction gas to any centrifugal compressor reduces its efficiency Capacity can
115. s and via standard control wiring between the chillers and auxiliary control points The optional Chiller System Controller is a separate panel that controls up to12 MicroTech panels optimizing the entire central plant operation All CSC panels have the following features Multiple compressor programmable sequencing 12 stages of tower control Analog control signal for a three way tower bypass valve or tower variable speed fan Secondary pump control including lead lag and sequencing Single point BMS interface for reset and demand limiting of all machines Expanded time clock for multiple machine control Temperature monitoring of primary and secondary chilled water loop outside air temperature and tower water supply and return temperature Central on off control point for all machines Optimized morning start up to insure full cooling at a specified time Figure 6 Multiple Machine Control Multiple Machine Control _ Tower Bypass Control Valve Pneumatic or Electric 12 Stages Cooling Outdoor Air Sensor ESSE I Tower Control Demand Limiting All Units mm 4 20mA DC Signal For _ Secondary Chilled Water Pumps a a Microtech PC DOS MS DOS o by o Compatible Computer 1111 E dd 4 20mA DC Signal For Reset of Chilled Water All Units With McQuay Software To Additional Units Product Manual PM WSC WDC 2 23 24 Condenser water pump control relay Wa
116. s above atmospheric pressure in the entire refrigerant circuit Negative low pressure systems require a purge unit to remove contaminants non condensables water vapor etc that leak into the chiller during operation and compromise chiller performance Purge units even the new high efficiency types regularly have to vent refrigerant to the atmosphere along with the non condensables The 1990 Clean Air Act has prohibited the intentional venting of refrigerant since July 1 1992 The environmentally responsible positive pressure system eliminates this regular venting of refrigerant Great care is taken by manufacturers and service personnel to ensure that refrigeration systems are dry when they are manufactured or serviced It makes no sense at all to buy a negative pressure HCFC 123 chiller that ingests water vapor during normal operation In addition to the refrigerant loss and maintenance problems of a purge system negative pressure chillers require a vacuum prevention system This system heats the refrigerant during off cycles to a positive pressure Unfortunately the vacuum prevention system only works when the chiller is off and cannot prevent vacuum related problems when the chiller is operating Plus it s a heating system requiring energy Sustainable Performance Because of their positive pressure design McQuay centrifugal chillers offer greater sustainable performance over the life of the chiller Positive pressure means no intrusi
117. s of compressor operated and non compressor purge systems are used Their efficiencies vary from 50 to 80 on older style units and are over 95 on newer high efficiency systems The efficiency is a measure of the quantity of refrigerant pumped to the atmosphere along with the undesirable contaminants Thus the need for a purge system is accompanied by the periodic release of refrigerant into the atmosphere and attendant annual refrigerant cost All McQuay centrifugal chillers use a positive pressure refrigerant There is e No absorption of impurities into the refrigerant circuit e No breakdown of motor insulation refrigerant or lubricant e No increase in operating cost due to displacement of heat transfer surface by non condensables e No crevice corrosion and tube failure due to moisture in the system e No annual service expense to maintain and rebuild purge unit e No abnormal annual service expense for oil filter and refrigerant replacement e No periodic emissions of refrigerant into the atmosphere Environmentally and Operator Safe The Real Facts As the air conditioning industry prepares for the future HFC 134a stands out as the logical choice when using a balanced approach The balanced approach takes into account the following facts on environmental concerns e ODP Ozone Depletion Potential measures the impact of a substance on the depletion of the ozone layer in the upper atmosphere With refrigerants this action is caused
118. se width modulated output IGBT insulated gate bipolar transistors power technology full power rating at 2kHz DC bus inductor choke and wireless construction Units 240 amps and below shall be air cooled units above 241 amps shall be water cooled All heat producing devices shall be contained in a single heatsink with single inlet and out connections for the connection of chilled water When factory mounted on the chiller package the water connections shall be piped and leak tested at the factory F CONTROL PANELS A microprocessor based control panel shall be furnished for each compressor and shall be fully wired and factory mounted on the chiller The control panels shall be independent allowing one compressor to operate with the other panel removed The control panels shall also be interconnected to provide lead and lag control as well as load balancing when two compressors are running The compressor with fewest starts will start first and the unit with the most hours will shut off first Each panel shall have the following features 1 Product Manual PM WSC WDC 2 The display shall have a minimum of 160 character liquid crystal display and be backlit with a light emitting diode Messages shall be in plain English Coded two or three character displays are not acceptable The following information shall be available on the display with simple entry on the keypad a Entering and leaving chilled and condenser water temperatures
119. si 1552 kPa on WDC units Water side design is 150 psi 1034 kPa on both Pumpdown To facilitate compressor service all McQuay centrifugal chillers are designed to permit pumpdown and isolation of the entire refrigerant charge in the unit s condenser Dual compressor units and single compressor units equipped with the optional suction shutoff valve can also be pumped down into the evaporator No separate pumpout receiver is required Table 2 Condenser Physical Data Pumpdown Water Number of Condenser Code WSC WDC S Vessel Weight Relief Capacity Ib kg Capacity gal L Ib kg Valves SEE Do ser TES 1645 748 C1612 C1809 C1812 C2009 C2012 C2209 C2212 C2212 C2216 C2416 C2609 C2612 C2616 C3009 C3012 C3016 C3612 C3616 C4212 C4216 C4220 C4812 C4816 C4820 Notes T Condenser pumpdown capacity based on 90 full at 90 F 2 Water capacity based on standard configuration and standard heads and may be less with lower tube counts 3 See Relief Valves section on following page for additional information 2528 2596 1169 2838 1287 89 337 3075 1395 3861 1751 143 540 4647 2188 83 314 2737 1245 9 3650 1660 5346 2425 3775 2537 5033 3383 6752 3063 7095 3219 9575 4343 12662 5743 17164 7785 12843 5826 18807 8530 23106 10481 cuo x Cine x cis X wA ee co x co x ces x co x co cmo cer
120. situations Optimizes equipment room space Factory testing assures trouble free startups and reliable operation Insures consistent quality for long trouble free operation Certification Full ARI 550 590 participation and certification has been an on going commitment at McQuay International The ARI label affixed to certified units certifies that the unit will meet the specified performance This equipment is certified in accordance with ARI Standard 550 590 latest edition provided the application ratings are within the scope of the certification program The program excludes the following applications air and evaporative cooled chillers capacity exceeding 2000 tons 7000 kW on 60 hertz service voltages above 5000 volts brine and special fluids other than water and heat recovery units The capacity range for 50 hertz is 200 to 1 000 tons 700 to 3500 kW Product Manual PM WSC WDC 2 3 Customer Benefits Wide Choice of Capacities and Efficiencies The range of capacities and chiller types shown in the following chart gives the plant designer the ability to pick and chose the exact capacity and optimum chiller type and efficiency for either a single or multiple unit chiller plant This flexibility is also a tremendous asset for replacement chiller applications McQuay Offers the Widest Choice of ARI Certified Ozone Safe Centrifugal Chillers TONS Single Compressor Chillers Single Compressor with VFD Dual Com
121. t 75 of full load to approximately 35 at 50 load and reduced to 25 of the full load value at 25 load This is a significant owner benefit considering that most chillers spend most of their operating hours at part load operation Product Manual PM WSC WDC 2 57 58 VFD Construction 1 2 3 4 5 6 7 8 Contains a line to 115 volt fused transformer to supply power to the control circuit oil heaters and oil pump Equipped with redundant motor control relays with coils in series The VFD is current rated at 2 kHz carrier frequency for all 200 1000 HP drives The drive is capable of running at 110 of nameplate current continuously and provides a minimum of 150 of this rated current for 5 seconds They will not generate damaging voltage pulses at the motor terminals when applied within 500 feet of each other Both Drive and Motor comply with NEMA MGI section 30 40 4 2 which specifies these limits at a maximum peak voltage of 1600 Volts and a minimum rise time of 1 microseconds Units drawing 240 amps or less are air cooled All others are water cooled Factory mounted water cooled VFDs are factory piped to chilled water inlet and outlet nozzles Freestanding water cooled units require chilled water supply and return piping for the VFD cooling VFD has a liquid cooled heat sink assembly enabling liquid cooling of the drive through a single inlet and outlet connection point dissipating a maximum of 25 000 BTU Hr f
122. tap A clearly marked timer shall be adjustable from 0 to 30 seconds Or Wye Delta Closed Transition The wye contactor shall be capable of handling 33 of the delta locked rotor current and be equipped with properly sized resistors to provide a smooth transition The resistors shall be protected with a transition resistor protector tripping in a maximum of two seconds locking out the starter and shall be manually reset A clearly marked transition timer shall be adjustable from 0 to 30 seconds Or Solid State Reduced Voltage Starter shall be furnished with silicon controlled rectifiers 10 11 12 SCR connected for starting and include a bypass contactor When operating speed is reached the bypass contactor shall be energized removing the SCRs from the circuit during normal running The starter shall be capable of across the line starting in an emergency Starters shall be coordinated with the chiller package s making certain all terminals are properly marked according to the chiller manufacturer s wiring diagrams The starters shall be equipped with redundant motor control relays MCR with coils in parallel The relays interconnect the starters with the unit control panels and directly operate the main motor contactors The MCRs shall constitute the only means of energizing the motor contacts The main contactors shall have a normally open and a normally closed auxiliary contact rated at 125VA pilot duty at 1
123. ter drier cores water separation tube sight glass drain and air discharge port Air and water are separated from the refrigerant vapor and accumulated in the purge tank 75 E 4 The pumpout system shall consist of a small compressor and a restriction device located at the pumpout compressor suction connection 5 The purge unit shall be connected to a 100 reclaim device Vacuum Prevention System HCFC 123 Chillers Only Chiller manufacturer shall supply and install a vacuum prevention system for each chiller The system shall constantly maintain 0 05 psig inside the vessel during non operational periods The system shall consist of a precision pressure controller two silicon blanket heaters a pressure transducer and solid state safety circuit Refrigerant Detection Device HCFC 123 Chillers Only Chiller manufacturer shall supply and install a refrigerant detection device and alarm capable of monitoring refrigerant at a level of 10 ppm Due to the critical nature of this device and possible owner liability the chiller manufacturer shall guarantee and maintain the detection monitor for five years after owner acceptance of the system Waffle type vibration pads for field mounting under unit feet PART 3 EXECUTION 3 1 INSTALLATION A B nm 3 2 START UP A B 76 Install according to manufacturer s requirements shop drawings and Contract Documents Adjust chiller alignment on concrete foundations sole
124. ter flow through the condenser should be discontinued when the chiller is inoperative Continuous flow through a cooling tower without inclusion of building heat in the water will overcool condenser water if tower bypass is not employed and will unnecessarily depress the chiller s refrigerant pressure Where energy conservation is desirable shutting off condenser water flow when the chiller is not operating provides a practical inexpensive method of saving power Alarm circuit Terminals are provided in each unit control panel to supply 24 volt AC power to an external alarm circuit A 25 VA low amp draw relay coil may be connected to these terminals The coil will be deenergized when any of the unit s or system s protective controls function The alarm is not included Operating Sequence With the control panel Stop Auto switch in the Auto position the unit will start provided that 1 The chilled water sensor is calling for cooling No time delay is restraining operation A remote start stop switch is not open preventing unit operation No safety switch has been tripped and not reset HO qe Compressor is unloaded and lubricant temperature and pressure are within prescribed limits The statement Waiting to load and the countdown period in seconds assigned to it assumes that the water temperature sensed by the chilled water temperature sensor may not represent the entire chilled water system temperature if the chilled water pump h
125. the most popular type for centrifugal chiller applications It reduces inrush current by first connecting six motor terminals in a Wye configuration to reduce the maximum inrush current to 33 3 of locked rotor amps and producing 33 3 of normal starting torque After a brief delay the electrical load is momentarily transferred to resistors while the motor terminal connections are changed to the delta configuration The resistors minimize the second inrush current when the Delta leads becomes active Open transition starters without resistors are not recommended Autotransformer This starter type uses a transformer with 50 65 and 80 taps The taps determine the initial voltage and resulting inrush amps that will reach the motor For centrifugal compressors the 65 tap is used allowing 45 of normal inrush current and generating 42 of starting torque The 50 tap will usually not generate enough starting torque and the 80 tap allows unnecessary inrush 67 of LRA After a designated time period a bypass contactor closes allowing normal current to flow to the motor and removes the transformers from service There is little reason to use autotransformer type starters with centrifugal compressors except for applications where it is desirable to have the same type of starter throughout a facility Solid state starters The solid state starters are another excellent type of starter for centrifugal compressors This starter uses solid state s
126. tic expansion valve meters refrigerant flow in direct response to the suction superheat regardless of changing load or condensing temperatures In doing so full utilization of compressor evaporator and condenser efficiency over the entire operating range is achieved Intermittent refrigerant flood back and excessive superheat characteristic of orifices and floats are eliminated Product Manual PM WSC WDC 2 Factory Performance Test Fast and trouble free startup and operation All WSC and WDC chillers are factory tested on ARI certified microprocessor based test stands The test stand microprocessors interface with the chiller MicroTech controls allowing monitoring of all aspects of the test stand and chiller operation The test procedure starts with dehydration and evacuation of the refrigerant circuit and charging with refrigerant and lubricant This is followed by a run test at job conditions of flow and temperature Compressors must meet a stringent 0 14 in sec vibration limit and the entire unit must pass a moisture limit of 30 ppm The testing ensures correct operation prior to shipment and allows factory calibration of chiller operating controls Optional Certified Test A McQuay engineer oversees the testing certifies the accuracy of the computerized results and translates the test data onto an easy to read spreadsheet The tests can be run at ARI load points between 10 and 100 and are run to ARI tolerance of capacity and power 50
127. tion of leaving chilled water temperature entering condenser water temperature evaporator and condenser flow rates number of passes and fouling factors Glycol applications may also be specified Glycol operation The addition of glycol to the chilled water system for freeze protection may be required for special applications Glycol solutions are required where the evaporating temperatures are below 33 F 1 C ARI Certification McQuay International has an on going commitment to supply chillers that perform as specified To this extent McQuay centrifugal chillers are part of the ARI Certification On going performance verification of chiller capacity and power input plus ARI certified computerized selection output assure the owner of specified performance in accordance with the latest version of ARI Standard 550 590 All chillers that fall within the scope of the certification program have an ARI certification label at no cost to the owner Equipment covered by the ARI certification program include all water cooled centrifugal and screw water chilling packages rated up to 2000 tons 7 000 kW for 60 hertz service at ARI standard rating conditions hermetic or open drive with electric driven motor not exceeding 5000 volts and cooling water not glycol For 50 hertz application the capacity range covered is 200 to 1 000 tons 700 to 3500 kW Published certified ratings verified through testing by ARI include e Capacity tons kW e Power
128. tor and voltage found in the Motor Data Tables Wiring and Conduit Wire sizes should comply with local and state electrical codes Where total amperes require larger conductors than a single conduit would permit limited by dimensions of motor terminal box two or more conduits may be used Where multiple conduits are used all three phases must be balanced in each conduit Failure to balance each conduit will result in excessive heating of the conductors and unbalanced voltage An interposing relay may be required on remote mounted starter applications when the length of the conductors run between the chiller and starter is excessive Note On WDC dual compressor units dual power leads are standard requiring separate power leads properly sized and protected to each compressor starter Separate disconnects must be used Motor Code Data Nominal shaft horsepower Compressor that motor is used on 050 063 to 087 100 to 126 60 Hertz Motor Code Voltage Code Nf B P v w luta 220 229 242 253 264 418 484 506 528 2640 3630 4575 7260 10005 MaxkW 1 87 87 87 86 86 se 87 86 86 o eee cp a duos 050 Tosco Poor Amps Troe Tae oar oeo Tose leis as pes ue Power Factor Max kW 90 90 90 90 89 90 90 90 89 869 T a35 O O i in f nofo po pop 7 050 Locked Rotor Amps 1548 1610 1291 1350 1409 832 646 675 704 544 P
129. tor or condenser and the length of piping to be run Discharge capacity for HFC 134a vessels is calculated as follows C 2 0433xDxL Where C Minimum discharge capacity lbs of air min D Vessel diameter in L Vessel length ft Example E3016 Evaporator HFC 134a Refrigerant 75 equivalent feet of piping C 0133x30x16 63 8 Lbs of air min From the table below 75 feet of piping for 63 8 Ib of air min at 180 psig valve setting requires a 2 diameter pipe Table 4 Discharge Capacity Ibs of Air Min EQUIVALENT DIAMETER STANDARD WALL IRON PIPE LENGTH OF 1 25mm 1 25 32mm 1 5 38mm 2 50mm 2 5 64mm 3 76mm DISCHARGE a VALVE PRESSURE SETTNG psi FT 8 100 30 5 15 2 1 19 0 4 3 49 9 55 4 82 6 92 9 103 3 129 6 145 8 162 0 222 5 250 3 278 1 150 45 7 12 4 14 0 1 7 84 2 105 1 11 181 2 2 204 27 7 1 13 91 97 1 11 1 A S l 60 Y Note Standard relief valve settings 1 WDC units evaporator 180 psig condenser 225 psig 2 WSC units evaporator 200 psig condenser 200 psig See note on next page Product Manual PM WSC WDC 2 Note Per ASHRAE Standard 15 the pipe size may not be less than the relief device meaning a minimum 1 diameter pipe is required The discharge from more than one relief valve may be run into a common header the area of which shall not be less than the sum of the areas of the connected pipes For further details refer to AS
130. trolled water cooled oil cooler Coolers located inside the evaporator or condenser are not acceptable due to inaccessibility A positive displacement oil pump shall be powered through the unit control transformer Refrigerant Evaporator and Condenser 1 Evaporator and condenser shall be of the shell and tube type designed constructed tested and stamped according to the requirements of the ASME Code Section VIII Regardless of the operating pressure the refrigerant side of each vessel will bear the ASME stamp indicating compliance with the code and indicating a test pressure of 1 3 times the working pressure but not less than 100 psig Provide intermediate tube supports at a maximum of 24 inch spacing Tubes shall be enhanced for maximum heat transfer rolled into steel tube sheets and sealed with Locktite or equal sealer The tubes shall be individually replaceable Provide isolation valves and sufficient volume to hold the full refrigerant charge in the condenser or provide a separate pumpout system with storage tank The water sides shall be designed for a minimum of 150 psi or as specified elsewhere Vents and drains shall be provided Evaporator minimum refrigerant temperature shall be 33 F Product Manual PM WSC WDC 2 6 A self metering and adjustable thermal expansion valve shall control refrigerant flow to the evaporator Fixed orifice devices or float controls with hot gas bypass are not acceptable because of inefficie
131. ts without rolling 3 Provide sufficient isolation valves and condenser volume to hold full refrigerant charge in the condenser during servicing or provide a separate pumpout system and storage tank sufficient to hold the charge of the largest unit being furnished 4 The water sides shall be designed for a minimum of 150 psig or as specified elsewhere Vents and drains shall be provided Chilled water minimum refrigerant temperature shall be 33 F 6 A self metering and adjustable thermal expansion valve shall control refrigerant flow to the evaporator Fixed orifice devices or float controls with hot gas bypass are not acceptable because of inefficient control at low load conditions The liquid line shall have a moisture indicating sight glass d T The evaporator and condenser shall be separate shells A single shell containing both vessel functions is not acceptable because of the possibility of internal leaks 8 Reseating type spring loaded pressure relief valves according to ASHRAE 15 safety code shall be furnished The evaporator shall be provided with single or multiple valves The condenser shall be provided with dual relief valves equipped with a transfer valve so one valve can be removed for testing or replacement without loss of refrigerant or removal of refrigerant from the vessel Rupture disks are not acceptable 9 The evaporator suction line and any other component or part of a component subject to condensing moisture shal
132. uble heat transfer surface refrigerant and refrigerant flow control Product Manual PM WSC WDC 2 19 Control Features 20 All McQuay Chillers Feature MicroTech Controls McQuay has incorporated the latest microprocessor technology into the MicroTech control system to give you the ultimate in centrifugal chiller control The control includes many energy saving features not found in any other microprocessor system on the market today MicroTech s innovative design will keep your chiller running efficiently day in day out for years to come FEATURE Easy integration into Building Management System via OPEN PROTOCOL Remote PC monitoring available via direct connection or modem Easy to read 4 line by 40 character backlit display in plain English or SI units Precise 0 2 F chilled water control Proactive pre alarm correction of off condition upset chiller stays online Automatic control of chilled water and condenser water pumps Controls up to four stages of tower fans and modulation of tower fan or bypass valve Internal 7 day 14 holiday clock with programmable duration Eight previous alarms and attendant BENEFIT Designer open to select any BMS supplier and MicroTech will interface with it Provides central remote control and monitoring of any MicroTech panel Operators can observe operation at a glance and easily select various menus Provides stability in chilled water system Activates alarm
133. um efficiency at peak and more importantly at part load is a function of the total compressor and chiller design Included are e Motor efficiency e Refrigerant type e Condenser and evaporator surfaces e Compressor mechanical friction e Impeller and vane design e Refrigerant flow passages Of these the least considered performance factor on actual versus theoretical performance is the refrigerant flow passages between the discharge of one impeller and the inlet to the next impeller on multi stage machine design The energy loss in a single passage will be greater or equal to the loss in the suction passage between the evaporator outlet and the first stage impeller inlet depending upon the compactness of the total compressor design Single stage impeller design eliminates that additional loss and provides an opportunity for maximum system efficiency Product Manual PM WSC WDC 2 9 10 The primary advantage to multi stage centrifugal operation in the pressure and volume ranges characteristic of typical air conditioning systems is the expansion of impeller head coefficients at reduced volumetric flows or cooling loads The McQuay backward inclined SINGLE STAGE IMPELLER combined with the patented movable diffuser at the impeller discharge provides a stable operating range superior to multi stage systems Thus selection of McQuay chillers permits operation from 100 to 10 capacity to 5 on WDC dual compressor chillers without surging an
134. umpout systems provide a means to collect and contain the refrigerant charge without loss when the access to internal chiller components is required for service McQuay condensers are sized to hold the entire unit refrigerant charge when not more than 90 full at 90 F 32 C ambient temperature They are equipped with a tight seating check valve at the hot gas inlet and a manual shutoff valve in the liquid outlet These valves coupled with the condenser design satisfy the stringent requirements of the U S Department of Transportation for refrigerant shipping containers as well as ASME vessel codes When service is required the refrigerant charge may be pumped down into the condenser by compressor operation and use of a refrigerant transfer unit All dual compressor units and single compressor units equipped with an optional suction shutoff valve can also be pumped down to the evaporator Elimination of the cost and space requirements of an external pumpout system is a major McQuay advantage Thermal Expansion Valves Controlled refrigerant flow over the entire capacity range saves energy and dollars Cooling loads and condenser water temperatures can change constantly Refrigerant float valves and orifices on competitive chillers are selected for peak load and peak condenser water temperatures and offer only partial control of refrigerant flow at operating conditions experienced over 95 of the time On McQuay chillers a pilot operated thermosta
135. urer shall warrant the shaft seal reservoir and float valve system against leakage of oil and refrigerant to the outside of the refrigerating unit for a period of 5 years from the initial start up including parts and labor to replace a defective seal and any refrigerant required to trim the charge original specifications 4 The starter must comply with the requirements of Section 1 2 5 AII controllers are to be continuous duty AC magnetic type constructed according to NEMA standards for Industrial Controls and Systems ICS and capable of carrying the specified current on a continuous basis The starter shall be Autotransformer The autotransformer starter shall be of the closed transition type and equipped with multiple taps for 80 65 50 and set up for the 65 tap A clearly marked timer shall be adjustable from 0 to 30 seconds Or Wye Delta Closed Transition The wye contactor shall be capable of handling 33 of the delta locked rotor current and be equipped with properly sized resistors to provide a smooth transition The resistors shall be protected with a transition resistor protector tripping in a maximum of two seconds locking out the starter and shall be manually reset A clearly marked transition timer shall be adjustable from 0 to 30 seconds Or Solid State Reduced Voltage Starter shall be furnished with silicon controlled rectifiers SCR connected for starting and include a bypass contactor When
136. witching devices called SCRs Silicon Controlled Rectifiers that control the flow of current to the motor during start up The SCR s control the amount of voltage that reaches the motor which in turn controls the motor s acceleration and current inrush Eventually full voltage is applied and a bypass contactor is energized The bypass contactor which is standard in the McQuay solid state starters removes the SCR s from service and eliminates SCR losses and heat buildup while the unit is operating Although setpoints are determined by the compressor size motor characteristics and starting torque requirements usually are a minimum of three times the RLA for the compressor s specific application Solid state starters are generally used in applications where it is desirable to provide precise control of motor starting characteristics The inrush current can sometimes be reduced below Wye Delta starters in severely limited utility electrical distribution systems Product Manual PM WSC WDC 2 Options for Low Voltage Starters Canadian Standards Association CSA certification and label Circuit breaker as a control disconnect Fuse block fuses by others with disconnect Ground fault protection Medium Voltage Starters 2300 to 6900 Volts Standard Equipment Medium voltage starters are NEMA Class E2 continuous duty AC and include isolated vertical line contactors drawout three pole gang operated line isolating switch current limiting fuse bl
137. xternally enhanced copper and are mechanically bonded to steel tube sheets Standard tubes are 0 025 inch wall thickness copper in the evaporator and condenser Optional tubes include 0 028 inch and 0 035 inch wall thickness on either vessels and 90 10 cupro nickel 304 stainless steel or titanium material Clad tube sheets and epoxy coated heads are included when other than copper tubes are specified Vessels are available for 1 2 or 3 pass water flow A 3 4 thick vinyl nitrate polymer evaporator insulation is standard All seams are glued to form an effective vapor barrier The entire chiller barrel including non connection heads and tube sheets are factory insulated Detailed information on the insulation can be found under Physical Data in this catalog Lubrication System A separately driven electric oil pump assembly supplies lubrication at controlled temperature and pressure to all bearing surfaces and is the source of hydraulic pressure for the capacity control system Inlet Vanes gt Oil To The control system will not allow the compressor to start until oil pressure at the proper temperature is established and also Control allows the oil pump to operate after compressor shutdown to assure lubrication during coast down Emergency i g l Coast Down ubricant from the pump 1s supplied to the Oil Return compressor through a water cooled brazed To Oil Pump Refrige

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