24
Centrifugal Chillers
D-EIMWC00804-14EN
2.
Pressure drops include valves on the unit.
Table 7, Freestanding VFD, Cooling Requirements
Cooling
Water
Cooling
Water
Cooling
Water
Cooling
Water
DWSC/DHSC 063 - 087
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
DWSC/DHSC 100 - 126
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
