Product Manual AGR-3
AGR 070A through 100A
13
6.
Calculate chilled water flow:
Water flow (at corrected capacity) =
= 155.3 GPM
64.7
24
10
tons
F
×
°
Glycol flow (at 40% solution) = 1.121 X 155.3 GPM = 174.1 GPM
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.
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 tables are based on a 10°F (5.5°C) temperature drop through the evaporator. 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 temperature that can be circulated through the evaporator in a non-operating mode
is 100°F (37.8°C). Maximum entering temperature during operation is 90
°
F (32.2
°
C).
Table 1, Ethylene Glycol
Freeze Point
%
E.G.
°F
°C
Capacity
Power
Flow
PD
10
23.0
-5
0.991
0.996
1.013
1.070
20
14.0
-10
0.982
0.992
1.040
1.129
30
1.4
-17
0.972
0.986
1.074
1.181
40
-13.0
-25
0.961
0.976
1.121
1.263
50
-34.6
-37
0.946
0.966
1.178
1.308
Table 2, Propylene glycol
Freeze Point
%
P.G.
°F
°C
Capacity
Power
Flow
PD
10
26
-3
0.987
0.992
1.010
1.068
20
19
-7
0.975
0.985
1.028
1.147
30
9
-13
0.962
0.978
1.050
1.248
40
-5
-21
0.946
0.971
1.078
1.366
50
-27
-33
0.929
0.965
1.116
1.481
NOTE: Ethylene and propylene glycol ratings are outside the scope of
Standard 550/590-98 certification program