Condenser Water - Daikin WCT Series Operating & Maintenance Manual

Condenser Water

Cooling towers used with Daikin centrifugal chillers are normally selected for maximum condenser
inlet water temperatures between 75°F and 90°F (24°C and 32°C). Lower entering water temperatures
are desirable from the standpoint of energy reduction, but a minimum does exist.
When the ambient wet bulb temperature is lower than design, the condenser water temperature can be
allowed to fall. The resultant lower condensing temperature will improve chiller performance.
WCT chillers are equipped with electronic expansion valves (EEV) and will operate with entering
condenser water temperatures as low as calculated by the following equation and shown in the chart
following.
Note: Provisions or modifications need to be made in the event of inverted starts (condenser water
colder than chilled water). For example, 3 way bypass valve controlled by the chiller, or tower
controls.
Min. ECWT = 10.973 + LCHWT – 0.17 * CHWDT
Figure 38, Minimum Operating Entering Condenser Water Temperature (10 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
OMM WCT

ECWT = Entering condenser water temperature

LCHWT = Leaving chilled water temperature

CHWDT = Chilled Water Delta-T at full load
FL

PLD = The percent chiller load point to be checked
70.00
65.00
60.00
55.00
50.00
45.00
0 10 20 30 40 50 60 70 80 90 100 110
Centrifugal Chillers
(PLD/100) + 8 * (PLD/100)2
FL
Percent Load
46.0 F LCHWT
44.6 F LCHWT
44.0 F LCHWT
42.0 F LCHWT
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