Filter
Top Products
94 TRG-TRC016-EN
notes
period four
Chiller-Plant Control
Another control function that is desirable is called soft loading. It is typically
used when the system has been off for an extended period of time and the
chilled-water temperature is the same as the ambient temperature inside the
building.
Soft loading either delays turning on additional chillers or varies the chilled-
water set point, allowing the operating chillers to gradually catch up to the
building pull-down load. This results in a very smooth pull-down, prevents
overshooting the set point, and operates only the equipment required to satisfy
the actual system load.
Soft Loading
supply
supply
-
-
water temperature
water temperature
operating time, minutes
operating time, minutes
two chillers
two chillers
soft loading
soft loading
(one chiller)
(one chiller)
set point
set point
60
60
30
30
0
0
80°F
80°F
[26.7°C]
[26.7°C]
60°F
60°F
[15.6°C]
[15.6°C]
40°F
40°F
[4.4°C]
[4.4°C]
Figure 102