"McQuay" is a registered trademark of McQuay International
"Illustrations and data cover the McQuay International products at the time of publication and we reserve the right to
make changes in design and construction at anytime without notice"
2001 McQuay International
ISO Certified
2
AGR 070A through 100AProduct Manual AGR-3
Introduction
N
McQuay offers air-cooled chillers from 10 through 425 tons (35 - 1500 kW). This
manual covers two varieties of the reciprocating compressor, air-cooled Global
Chiller Line:
AGR 070 AS - AGR 100AS, Packaged Air-Cooled Chillers, R-22 and R-134a
AGR 070AM - AGR 100AM, Air-Cooled with Remote Evaporator, R-22 only
Nomenclature
A G R - XXX A S
Air-Cooled
Global
Reciprocating Compressor
AGR-AS Model ARI Standard 550/590-98 Certified
Efficiency
Reliability
Features and Benefits
Cross-circuit compresso r staging
•
Copeland Disc us compressors
•
Exceeds ASHRAE Standard 90.1 for
•
efficiency
Rugged, proven c ompressor design
•
Factory installed operating and equipment
•
protection controls
Code and agency approval
•
Application
S= Standard Cooling
=
Design Vintage
ominal To ns
Complete factory assembly and testing
Flexibility
Serviceability
Product Manual AGR-3AGR 070A through 100A
Sizes available in convenient 5 ton
increments
Multiple control options
Remote evaporator available (R-22 only)
•
Available with HCFC-22 or HFC 134a
•
Dual refrigerant circuits
•
Easy servicing -- All electrical and
•
refrigerant components are readily accessible
Small footprint
•
3
Design Advantages
Construction
Factory assembled and mounted on heavy-gauge powder coat painted, galvanized steel channel base.
This base distributes the unit weight for roof loading. Flexible installation is possible by virtue of the
unit’s small footprint and low sound level.
Compressors
The AGR product line uses Copeland DISCUS valve semi-hermetic compressors. These rugged
compressors are designed for R-22 and the high loading associated with air-cooled applications. They
operate under lighter loading with R-134a.
Semi-hermetic, 1750 rpm induction type motors are used. The motors are refrigerant-gas cooled.
Solid-state modules in the motor terminal box respond to temperature sensors imbedded in all three
motor windings, providing inherent thermal overload protection for all run and start conditions.
The compresso r ho using is c o nstr ucte d fro m clo se d gr ai ned , high nic kel co nte nt, a ll oy c ast -ir on with no
bolted joint between the motor and compressor. The housing includes a cast-iron cylinder head and
stator cover, and a crankcase oil sightglass. A suction strainer built into the compressor in the gas
stream between the suction service valve and the motor, filters out foreign and abrasive particles. An
internal relief valve relieves discharge pressure to the suction side for protection at high compression
ratios as required by ANSI/ASHRAE 15 Safety Code.
Main bearings are solid cast bronze insert type with oversized bearing areas that result in ultra-low
bearing loa ding.
The crankshaft is die-forged, high strength iron alloy with integral counterweights, statically and
dynamically balanced for smooth operation.
Connecting rods are lightweight aluminum with integral bearing surfaces on the crankshaft and piston
ends. Pistons are close grain cast iron with oil and compression rings. Piston pins are full floating type
for long life.
Compressors have a force-feed lubrication system with positive oil displacement, a reversible oil pump,
and an operating oil c harge. The pump feeds oil through r ifle drilled passages in the crankshaft to a ll
bearing surfaces. Magnetic plugs trap metal particles that enter the crankcase. The oil supply is filtered
through a large ar ea oil strainer. A crankcase heater minimize s oil d ilution b y refriger ant at co mpressor
startup.
Condenser Coils
Condenser coils have internally enhanced seamless copper tubes arranged in a staggered row pattern.
The coils are mechanically expanded into McQuay lanced and rippled aluminum fins with full fin
collars. An integral subcooler circuit provides subcooling to greatly reduce the possibility of liquid line
flashing. The exterior condenser coils are fitted with a vinyl-coated wire mesh protective guard.
Condenser Fans and Motors
Multiple direct drive dynamically balanced propeller fans operate in formed venturi openings at low tip
speeds for maximum efficiency and minimum noise and vibration. A heavy-gauge vinyl-coated fan
guard protects each fan.
Each condenser fan motor is heavy-duty, 3-phase with permanently lubricated ball bearings and
inherent overload protection. SpeedTrol option includes a single-phase motor with fan speed control on
the lead fan per circuit. Fan motors on the AGR 070-100A are totally-enclosed-air-over (TEAO)
construction providing optimum environmental protection.
Copeland's Compliant Scroll® is a registered trademark of the Copeland Corporation, Sydney, Ohio.
4
AGR 070A through 100AProduct Manual AGR-3
Evaporator
The evaporator is direct expansion, shell-and-tube type with water flowing in the baffled shell side and refrigerant
flowing through the tubes. Two independent refrigerant circuits within the evaporator serve the units dual
refrigerant circuits.
The evaporator has a carbon steel shell and seamless high efficiency copper tubes roller expanded into a carbon
steel tube sheet. Water baffles are polypropylene to resist corrosion.
Refrigerant heads are carbon steel with multi-pass baffles to ensure oil return and are removable to permit access to
the tubes from either end. For water removal, 3/8" (10mm) vent and drain plugs are provided on the top and bottom
of the shell.
The evaporator is wrapped with an electric resistance heater cable and insulated with 3/4" (19mm) thick vinyl nitrate
polymer sheet insulation, protecting against water freeze-up at ambient air temperatures to -20°F (-29°C). An
ambient air thermostat controls the heater cable.
The fitted and glued in place insulation has a K factor of 0.28 at 75°F (23°C).
The refrigerant (tube) side maximum working pressure is 225 psig (1552 kPa). The water side working pressure is
225 psig (1552 kPa). Each evaporator is designed, constructed, inspected, and stamped according to the
requirements of the ASME Boiler and Pressure Vessel Code. Double thickness insulation is an available option.
On Model AGR AM units the evaporator is shipped separate for field mounting and piping to the outdoor unit.
The refrigerant specialties shown in Figure 1 (dotted lines) must be purchased from McQuay with the unit and
installed by the installing contractor.
NOTE:
The remote evaporator option is available on R-22 application only and is outside ARI certification.
Figure 1, AGR ---AM, Remote E vaporator Piping (One of two circuits shown)
NOTE:
protect against evaporator freeze-up under low water flow conditions.
Product Manual AGR-3AGR 070A through 100A
A water flow switch or both water flow switch and water pump starter interlock, must be field installed to
5
Electrical Control Center
Operating and equipment protection controls and motor starting components are separately housed in a
centrally located, weatherproof control panel with hinged and key locked doors. In addition to one of
the three types of control described in the next sections, the following components are housed in the
panel:
Power terminal block
•
Control, input, and output terminal block
•
120V control circuit transformer
•
Optional disconnect switch with through-the-door operating handle
•
Compressor contactors (circuit breakers are available as an option) (part winding on 208/230V,
•
across-the-line on 380/460/575V) compressor motor inherent thermal and overload protection is
standard.
Optional phase voltage monitor with under/over/phase reversal protection
•
Fan contactors with separate fuse blocks
•
The standard FanTrol system controls fan staging for control of refrigerant discharge pressure.
•
The FanTrol system cycles condenser fans based on discharge pressure and outdoor temperature
and is suited for operation to 40°F (4.4°C).
The optional SpeedTrol control uses both fan cycling and fan speed control on the lead fan per
•
circuit and allows operation to 0°F (-18°C) outdoor temperature.
Mechanical high pressure cutout
•
Global UNT Controller (Standard on R-22)
Microprocessor based control that accomplishes unit capacity control by 6-stage cross-circuit
compressor cycling and unloading based on leaving chilled water temperature. Setpoint and control
band are easily field adjusted. Anti-cycling and stage delay timers are included. Equipment protection
controls include low refrigerant pressure, low evaporator flow (field installed flow switch), low oil
pressure, and sensor failures. Outside air temperature sensor is standard. Reset options are; outside air,
return water, remote reset, demand limit, zone temperature reset. The optional Zone Terminal control is
required to adjust the reset setpoints. The UNT control is used only with R-22.
Thirty feet of sensor cable is included, rolled up in the control panel, on remote evaporator models.
Figure 2, Standard Global UNT Controller
6
AGR 070A through 100AProduct Manual AGR-3
Global UNT with Zone Terminal (optional)
Can be mounted in the chiller control panel or remotely located providing monitoring and adjusting of
certain functions.
Monitoring
•
Monitor up to three setting or sensed values
•
Monitor 18 different on/off inputs
•
Monitor alarm status via a flashing alarm light and flashing symbol
•
Adjusting allows adjustment of any flashing set points, three at a time, typically set up so that the
•
relationship between values can be viewed simultaneously. For example,
Display 1 = Lvg Water temp
•
Display 2 = Lvg Water SP
•
Display 3 = % Unit Load
•
Figure 3, Zone Terminal Configuration
Display Item List
Display Indicator Dot
Warning Signal
On/Off St at us
Display
Button 1
Mode
Selector
Button
Mode
Selector
Panel
Door
2
3
McQuay AGZ/AGR Global Chiller
Lvg Water Temp
Evap Pres #1
Evap Pres #2
OA/AI3 Input
OA/AI3 HiLimSP
OA/AI3 ResetSP
Lvg Water SP
LvgWtr RBnd SP
Contrl Band SP
Actual Lvg SP
Unoccpd Lvg SP
OA Lockout SP
% Unit Load
Lvg Low Lim SP
SoftSta Capcty
SoftStart Time
Cir #1 Starts
Cir #2 Starts
Operating Mode Indicator
MONITOR
ADJUST
TIME SCHEDULE
PASSWORD
ENTER
INSERT 10
Display Area 11
Display Area 21
Display Area 31
Up/Down Arrow Keys
ON OFF
Occupied
Flow Failure
OA Lockout
Cir#2Lead=On
Pmp/Stp #1=0
Pmp/Stp #2=0
MicroTech Control (optional on R-22, standard on R-134a)
Exclusive microprocessor control is common throughout McQuay equipment. The interface is a 12 key
keypad and 2-line, 40 character backlit liquid crystal display. The MicroTech continuously performs
self-diagnostic checks on all system temperatures, pressures, and equipment protection controls, and
will automatically shut down a circuit or the entire unit at fault conditions. The cause, time, and date of
the occurrence is recorded and can be displayed. The seven previous incidents are kept in memory for
service reference.
If a fault occurs, the controller takes preventive measures in an effort to keep the unit operating; staging
down capacity, activating a pre-alarm signal, and automatically switching to the alarm menu on the
display. Pre-alarms are self-clearing when the fault condition is no longer present.
Critical shutdown alarms such as high condenser pressure (with mechanical back up), freeze protection,
oil pressure (with mechanical back up), and low evaporator pressure are manual reset and must be
cleared at the keypad to resume operation.
Choose the MicroTech control and Open Protocol options to interface with virtually any building
management system and perform remot e monitor ing and co ntrol b y hard wiring o r mod em. A no minal
site license fee is required for BAS interface.
A single chiller can connect directly to the BAS. Two or more units will require an Open Protocol
Panel (OPM) for connection.
One hundred feet of sensor cable is included, rolled up in the control panel, on remote evaporator
models.
NOTE:
Figure 4, Optional MicroTech Control Panel
The MicroTech control is required on R-134a applications.
8
AGR 070A through 100AProduct Manual AGR-3
Selection Procedure
Packaged Chiller, Model AS, R-22
Selection with Inch-Pound (I-P) units
Table 9 covers the range of leaving evaporator water temperatures and outside ambient temperatures
included under ARI 550/590. The tables are based on a 10°F temperature drop through the evapor ator.
Adjustment factors for applications having other than a 10°F drop can be found in Table 3. The
minimum leaving chilled water temperature setpoint without glycol is 42°F. For glycol selections, see
Table 1 for ethylene or Table 2 for propylene glycol adjustment factors. Ratings are based on a 0.0001
fouling factor in the evaporator at sea level operation. For other fouling factors, different delta-Ts, or
altitude correction factors, see Table 3. For applications outside the catalog ratings contact your local
McQuay sales representative.
Selection example
Given: 67 tons minimum95°F ambient temperature
160 gpm, 55°F to 44°F chilled water 0.0001 fouling factor
1. From Performance Table 9, an AGR 070AS at the given conditions will produce 67.5 tons with a
compressor kW input of 77.1 and a unit EER of 9.6.
2. If any elements are unkno wn, use the following equation (water only) to calculate them:
tons−×
=GPM
24
Tdelta
3Determine the evaporator pressure drop. Using Figure 9, enter at 160 and follow up to the AGR
070AS line intersect. Read horizontally to obtain an evaporator pressure drop of 16.0 feet of water.
Selection example using ethylene glycol
Given:
64 tons minimum
95°F ambient temperature
54°F to 44°F chilled fluid
0.0001 fouling factor
Protect from freezing down to 0°F
1. From Table 1, select an ethylene glycol concentration of 40% to protect against freezing at 0°F.
2. At 40% ethylene glycol, the adjustment factors are: Capacity =0.961, kW = 0.976,
flow = 1.121, pressure drop = 1.263
3. Select the AGR 070AS and correct with 40% ethylene glycol factors.
Determine the evaporator pressure drop. Using Figure 9, enter at 155.7 (flow rate for water) and follow
up to the AGR 070AS line intersect. Read horizontally to obtain an evaporator pressure drop of 15.5
feet. The pressure drop for 40% glycol solution = 1.263 X 15.5 feet = 19.6 feet of water.
Product Manual AGR-3AGR 070A through 100A
9
Selection Procedure 60 Hertz, SI Units
Table 10, covers a range of leaving evaporator water temperatures and outside ambient temperatures.
The tables are b ased on a 5°C temper ature dro p through the evapo rator. The minimum leaving chilled
water temperature setpoint without glycol is 5.6°C. For brine selections, see Table 1 for ethylene or
Table 2 for propylene glycol adjustment factors. Ratings are based on a 0.0176 fouling factor in the
evaporator at sea level operation. For other fouling factors, different Delta-Ts, or altitude correction
factors, see Table 3. For applications outside the catalog ratings contact your local McQuay sales
representative.
Selection Example
Given:
235 kW cooling capacity required
35°C ambient air temperature
11 L/s, 12°C - 7°C chilled water temperature
0.0176 evaporator fouling factor
1. From Table 10, an AGR 070AS at the given conditions will produce 240.0 kW with a compressor
kW input of 77.5 and a COP of 2.84.
2. Determine the evaporator pressure drop. Using Figure 9, enter at 11 L/s and follow to the AGR
070AS line intersect. Read horizontally to obtain an evaporator pressure drop of 55 kPa of water.
Selection example using ethylene glycol
Given:
225 kW cooling capacity required
35°C ambient air temperature
11 L/s, 12°C - 7°C chilled water temperature
0.0176 evaporator fouling factor
Protect against freezing down to -18°C
1. From Table 1, select an ethylene glycol concentration of 40% to protect against freezing
at -18°C
2. At 40% ethylene glycol, the adjustment factors are: Capacity = 0.961, kW = 0.976,
GPM = 1.121, pressure drop = 1.263
3. Select the AGR 070AS and correct with 40% ethylene glycol factors.
7. Determine the evaporator pressure drop. Using Figure 9, enter at 11.0 L/s (flow rate for water) and
follow to the AGR 070AS line intersect. Read horizontally to obtain an evaporator pressure drop
of 55 kPa of water.
The pressure drop for 40% solution = 1.263 X 55 kPa = 69.5 kPa
10
AGR 070A through 100AProduct Manual AGR-3
Packaged Chiller, Model AS, R-134a
NOTE: R-134a performance is not ARI Certified
AGR performance with R-134a refrigerant is calculated from the R-22 ratings as follows:
1) Calculate the unit R-134a capacity;
2) Calculate the unit R-134a power input;
a) Calculate the unit R-22 power (kW shown in tables is compressor only);
22
b) Calculate the unit fan and control power (unaffected by refrigerant);
c) Calculate the R-134a compressor power;
d) Calculate the unit R-134a kW;
3) Calculate R-134a EER:
kWUnitR
−
=
134
multiply the R-22 capacity by 0.68.
12022
xTonsR
EERUnit
2222/
−=
multiply the R-22 compressor kW by 0.615
fan & contro l power from b)+R-134a compressor power c)
EERaR
134
=
134
MBHcapacityaR
kWUnitaR
TablefromkWCompressorRkWUnitRkWControlFan
Remote Evaporator, Model AM
Selection with Inch-Pound (I-P) units
Since the AGR-AM units always include a specific remote shell-and-tube evaporator,
the ratings are based on leaving chilled water temperature and ambient air temperature
from the Rating Tables corrected for line loss as follows.
Table 9 (Inch-Pound units) and Table 10 (SI units) cover the normal range of leaving evaporator water
temperatures and outside ambient air temperatures. The tables are based on a 10°F (5°C) temperature
drop thro ugh the evapora tor. Adjustment factors for applicati ons having other tha n a 10°F (5°C) drop
can be found in Table 3. The minimum leaving chilled water temperature setpoint without glycol is
42°F (5.6°C). For brine selections, see Table 1 for ethylene Table 2 for propylene glycol adjustment
factors. Ratings are based on a 0.0001 (0.0176) fouling factor in the evaporator at sea level operation.
For other fouling factors, derates for different delta-Ts, or altitude correction factors, see Table 3 . For
applications outside the catalog ratings contact your local McQuay sales representative.
The length and configuration of the interconnecting refrigerant piping will affect the system capacity.
Derates base d on e q uival ent lengt h o f pip e ar e gi ven i n Table 8. Re fer to App li ca tio n Da ta , Re fri ger ant
Piping section for guidelines.
The steps for selecting an AGR-AM are as follows:
1. Add 3% to the required cooling capacity (to approximate correction factors) and make a
preliminary unit selection from performance Table 9 or Table 10.
2. Divide the required capacity by the appropriate capacity correction factors: glycols from Table 1 or
Table 2; altitude, chilled water Delta T, or fouling factor Table 3; and refrigerant piping derate from
Table 8 as explained in step 3 below.
3. Determine the suction line size by summing the equivalent feet (from Table 4) of all the fittings
(use a sketch of the piping layout) and
of tubing. This will then equal the
unit suction connection size from Table 6 as the first try). Knowing the equivalent feet and the unit
size, check the line selection in Table 6 or Table 7 and correct if required.
4. If the unit rated capacity in the tables is less than the corrected required cap acity, redo the selection
with the next larger unit. In most cases the line size will be the unit connection size. If the
selection is satisfactory, correct the power (if applicable) and determine water pressure drop.
Product Manual AGR-3AGR 070A through 100A
adding the sum of these fitting losses
total equivalent feet
to the actual linear feet
. (To use the equivalent feet, start with the
11
Selection example
A
p
Given:
Figure 5, Sample Piping Layout
GR-AM
10 ft.
64 tons required capacity
95°F ambient temperature
Cool 154 gpm from 54°F to 44°F
Add 3% to the required capacity for approximate derate: 64 x 1.03 = 66 tons. From Performance Table
9, an AGR-070AM at the given conditions will produce 67.5 tons with a compressor kW input of 77.1
and a unit EER of 9.6.
1. Determine derate factors :
Altitude correction from Table 3: 0.986 Capacity, 1.009 Power
2. Piping cor rection:
Assume 2 1/8" suction line based on connection size in Table 6
(3) 90° Standard ells (Table 4)3 x 5 ft =15 ft
Plus actual linear feet70 ft
Total Equivalent Feet85 ft
Check Table 7 for size and find that 2 1/8” is acceptable size for oil carry. If the selected riser size
is too large, double risers would be required. See Refrigerant Piping section for important
information, including double riser layouts.
The capacity correction factor from Table 8 is 0.984.
3. The corrected capacity of the AGR is: 67.5 tons x 0.986{altitude} x 0.984{piping} = 65.5 tons
This satisfies the 64 ton requirement.
4. Correct the compressor power required: 77.1 kW x 1.009{altitude} = 77.8 kW.
5. Calculate the unit power input from corrected EER:
W = BTU / EER W =65.5 tons x 12,000 / (9.6 EER / 1.009) = 81.1 kW
6. Determine the evaporator pressure drop. Enter the pressure drop curves (Figure 9) at 154 gpm and
read up to AGR 070AM, read over to pressure drop of 15 ft.
Selection example using ethylene glycol
Given: 64 tons required capacity
95°F ambient temperature
54°F to 44°F chilled fluid
0.0001 fouling factor
Protect from freezing down to 0°F
1. From Table 1, select an ethylene glycol concentration of 40% to protect against freezing at 0°F.
2. At 40% ethylene glycol, the adjustment factors are: Capacity =0.961, kW = 0.976,
Flow = 1.121, pressure drop = 1.263
3. Select the AGR 070AM and correct with 40% ethylene glycol factors and piping correction factor.
Determine the evaporator pressure drop. Using Figure 9, enter at 155.3 GPM and follow up to the
AGR 070AM line intersect. Read horizontally to obtain an evaporator pressure drop of 15 feet. The
pressure drop for 40% solution = 1.263 X 15 feet = 19 feet.
Selection Procedure 60 Hz Metric Units
The selection procedure for Metric units is exactly the same as English except that Metric tables and
metric units are used.
Application Adjustment Factors
Ethylene and Propylene Glycol Factors
AGR units can operate with a leaving chilled fluid temperature range of 20°F (-6.7°C) to 60°F
(15.6°C). A glycol solution is required when leaving chilled fluid temperature is below 42°F (5.6°C).
The use of glycol will reduce the performance of the unit depending on concentration.
64.724
tonsF×
10
°
Altitude Correction Factors
Performance tables are based at sea level. Elevations other than sea level affect the performance of the
unit. The decreased air density will reduce condenser capacity and reduce the unit's performance. For
performance at elevations other than sea level refer to Table 3. Maximum allowable altitude is 6,000
feet (1830 meters).
Evaporator Temperature Drop Factors
Performance tab les are ba sed on a 10 °F (5.5°C) temperature drop through the evapora tor. Adjustment
factors for applications with temperature ranges from 6°F to 16°F (3.3°C to 8.9°C) are in Table 3.
Temperature drops outside this 6 to 16 degrees F (3.3 to 8.9 degrees C) range may affect the control
system's capability to maintain acceptable control and are not recommended.
The maximum water temperatur e that ca n b e c ir cul at ed thr o ugh the eva po r a to r i n a non-o p e ra ti ng mod e
is 100°F (37.8°C). Maximum entering temperature during operation is 90°F (32.2°C).
NOTE: Ethylene and propylene glycol ratings are outside the scope of
Freeze Point
°F°C
Freeze Point
°F°C
Standard 550/590-98 certification program
CapacityPowerFlowPD
CapacityPowerFlowPD
Product Manual AGR-3AGR 070A through 100A
13
Fouling factor
Performance tables are based on water with a fouling factor of
22
per ARI 550/590-98. As fouling increases,
/0176.0,,/0001.0
°×°
kWCmorBTUFxhrxft
performance decreases. For performance at other than 0.0001 (0.0176) fouling factor see Table 3.
Foreign matter in the chilled water system will adversely affect the heat transfer capability of the
evaporator, and could increase the pressure drop and reduce the water flow. To ensure optimum unit
operation, maintain proper water treatment.
1. Ratings based on HCFC-22, evaporator fouling of 0.00176, 0.048 l/s per kW, and sea level altitude. Remote evaporator units (AM) are outside ARI scope.
2. Interpolation is allowed; extrapolation is not permitted. Consult McQuay for performance outside the cataloged ratings.
3. kWi input is for compressors only. EER is for the entire unit, including compressors, fan motors and control power.
4. For LWT below 4.4°C and below please refer to Application Data.
5. For 208V units, multiply capacity and EER by 0.98
6. For units with SpeedTrol option, multiply capacity and EER by 0.98
7. Operation below 5.6°C requires glycol and performance adjustment.