20
Centrifugal Chillers
IM 1044-2
Table 9, Freestanding VFD, Cooling Requirements
Cooling
Water
Cooling
Water
Cooling
Water
Cooling
Water
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Flow, gpm
1.5
1.0
0.9
0.7
Inlet Temperature,
°
F
80.0
65.0
55.0
45.0
Outlet Temperature,
°
F
114
114
114
114
Pressure Drop, ft.
13.0
6.8
4.8
3.6
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Flow, gpm
2.5
1.9
1.5
1.3
Inlet Temperature,
°
F
80.0
65.0
55.0
45.0
Outlet Temperature,
°
F
114
114
114
114
Pressure Drop, ft.
25.2
15.7
11.4
9.3
Compressors using chilled water for oil cooling will often start with warm "chilled water" in the system until the
chilled water loop temperature is pulled down. Data given above includes that condition. As can be seen, with
cooling water in the 45
°
F to 65
°
F (7
°
C to 18
°
C) range, considerably less water will be used, and the pressure
drop will be greatly reduced.
When supplied with city water, the oil piping must discharge through a trap into an open drain to prevent
draining the cooler by siphoning. The city water can 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 can 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.
Figure 9, Oil Cooler Piping Across Chilled Water Pump
CHILLER
OIL COOLER
STOP
VALVE
STRAINER
MAX. 40 MESH
SOLENOID
VALVE
DRAIN VALVE
OR PLUG
STOP
VALUE
PUMP
R
S
