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–EIMWC00803-21_01EN - 22/57
4.9.4
Compressor
Table 5 - Compressor Weights
Compressor Size
79
87
100
113
126
Weight lb. (kg)
3200 (1440)
3200 (1440)
6000 (2700)
6000 (2700)
6000 (2700)
4.10 Oil Coolers
Daikin centrifugal chillers, sizes 079 through 126, have a factory-mounted, water-cooled oil cooler, temperature-controlled
water regulating valve and solenoid valve per compressor.
DWSC single compressor cooling water connections are located near the compressor and are shown on the specific u nit
certified drawings.
Field water piping to the inlet and outlet connections must be installed according to good piping practices and include stop
valves to isolate the cooler for servicing. A cleanable filter (40 mesh maximum), and drain valve or plug must also be field-
installed. The water supply for the oil cooler should be from the chilled water circuit or from a clean, independent source,
no warmer than 80
F (27
C), 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 p ump,
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 95
F and 105
F
(35
C and 40
C).
Table 6 - DWSC, Oil cooler Data
DWSC/DHSC 079 - 087
Cold Side Water
Flow, gpm
11.9
2.9
2.0
1.54
Inlet Temperature,
F
80.0
65.0
55.0
45.0
Outlet Temperature,
F
87.3
94.5
98.4
101.5
Pressure Drop, ft.
9.9
0.6
0.3
0.2
DWSC/DHSC 100 - 126
Cold Side Water
Flow, gpm
21.9
5.1
3.5
2.7
Inlet Temperature,
F
80.0
65.0
55.0
45.0
Outlet Temperature,
F
87.0
95.0
99.1
102.4
Pressure Drop, ft.
8.7
0.5
0.2
0.1
DWDC dual compressor units will have twice the cooling water flow rate of the comparable DWSC chiller and the pressure
drop will be the same.
Pressure drops include valves on the unit.
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 wa ter. In this case an
auxiliary booster pump can be used or city water employed.
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.
