D-EIMWC01308-16EN - 12/40
Figure 4,
Minimum Operating Entering Condenser Water Temperature (10
F Range)
Note
:
Some limitation in control may apply when operating chiller in the condition that ECWT is
same or above but still around minimum ECWT.
For example; at 44
F L
C
HWT, 10-degree F chilled water Delta-T, and 50% full load operation, the
entering condenser water temperature could be as low as 56
F.
The operating strategy for cooling tower fans requires some analysis. Regardless of power consumption
considerations, the minimum allowable entering condenser water temperature must be maintained.
Depending on local climatic conditions, using the lowest possible entering condenser water temperature
may be more costly in total system power consumed than the expected savings in chiller power would
suggest, due to the excessive fan power required.
Even with tower fan control, some form of water flow control, such as tower bypass, is recommended
and is required if fan control alone will not maintain minimum water temperatures.
For cold weather operation, the bypass valve and piping is required and should be inside the building.
Water Piping
Water Pumps
Avoid the use of two-pole pump motors. It is not uncommon to find that these pumps operate with
objectionable noise and vibration.
It is also possible to build up a frequency beat due to the slight difference in the operating rpm of the
pump motor and the Daikin centrifugal motor. Daikin encourages the use of four-pole pump motors.
Both the condenser and chilled water pumps’ discharge connections should be located to supply water
through the chiller at positive pressure.
In cases where the water pump noise can be objectionable, vibration isolation sections are recommended
at both the inlet and outlet of the pump. In most cases, it will not be necessary to provide vibration
45.00
50.00
55.00
60.00
65.00
70.00
0
10
20 30
40 50
60 70
80 90 100 110
Percent Load
E
C
W
T
,
(F
)
46.0 F LCHWT
44.6 F LCHWT
44.0 F LCHWT
42.0 F LCHWT
Summary of Contents for WCT
Page 39: ...D EIMWC01308 16EN 39 40 ...