Trane TRG-TRC016-EN manual Soft Loading

period four

Chiller-Plant Control

notes

Soft Loading

	80°F
	[26.7°C]	soft loading
temperature
		(onechiller)
	60°F
	[15.6°C]
supply-water
		set point
	40°F	twochillers
	[4.4°C]
	0	30	60

operatingtime, minutes Figure 102

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.

94 TRG-TRC016-EN