modelDownStartWithOn

Validate sequence of starting the staging down process which requires enabling a chiller

Information

This example validates Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.Processes.Subsequences.DownStart. It shows the beginning steps when the plant starts staging down. In this example, the staging down process requires enabling one chiller and disabling another chiller.

It stages from stage 2, which only has larger chiller enabled (chiller 2), down to stage 1 which only has smaller chiller enabled (chiller 1).

The staging process begins at 180 seconds. Before the moment, the chiller 1 is disabled and the chiller 2 is enabled.
Since 180 seconds, the operating chiller load is reduced from 2000 W to 1500 W (75% of the command load).
From 180 seconds to 480 seconds, the minimum flow setpoint (yChiWatMinFlowSet) changes from 1 m3/s to 2 m3/s, which are the minimal flow setpoints for 1 chiller operation and 2 chiller operations.
After the minimum chilled water flow setpoint is changed at 480 seconds, wait for another 60 seconds at 540 seconds, the head pressure control for the chiller 1 becomes enabled (yChiHeaCon[1]=true).
After 30 seconds at 570 seconds, the isolation valve of chiller 1 starts opening and becomes fully open at 870 seconds.
At 870 seconds, the chiller 1 becomes enabled.
After 300 seconds at 1170 seconds, the chiller 2 becomes disabled. The chiller demand limit is released, and the minimum chiller water flow setpoint then changes to the one for only chiller 1 operating.

Type	Name	Default	Description
Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.Processes.Subsequences.DownStart	staStaDow1		Chiller stage down when the process does require one chiller on and another chiller off
Buildings.Controls.OBC.CDL.Discrete.TriggeredSampler	demLimRel		To indicate if the demand limit has been released