modelUpWithoutOnOff

Information

This example validates Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Staging.Processes.Up.

It shows a process of staging up from stage 1 which requires only chiller 1 to be enabled, to stage 2 which requires both chiller 1 and 2 to be enabled. In stage 1 and 2, the required minimum chilled water flow setpoints are 1.0 m3/s and 2.0 m3/s, respectively. The process is below:

• Before 150 seconds, the plant is not in the staging process.
• At 150 seconds, the plant starts staging up (yStaPro=true). The operating chiller load is reduced from 2000 W to 1500 W (which is lower than 80% of the operating chiller load). Waiting for 5 minutes till to 450 seconds.
• After 300 seconds (byPasSetTim) to 750 seconds, the minimum chilled water flow setpoint slowly increases from 1.0 m3/s, to 2.0 m3/s which is for the case when both chiller 1 and 2 are operating. The setpoint is achieved at 760 seconds.
• Wait 60 seconds (aftByPasSetTim) to allow the loop to be stable, enabling the head pressure control of chiller 2 (yChiHeaCon[2]=true) at 820 seconds.
• After 30 seconds (waiTim) at 850 seconds, it starts slowly opens the chilled water isolation valve of chiller 2 (yChiWatIsoVal[2]). After 300 seconds (chaChiWatIsoTim) at 1150 seconds, the valve is fully open.
• At 1150 seconds, the chiller 2 becomes enabled. The chiller load demand is released. The staging process is done (yStaPro=false).

Components

Revisions

• May 31, 2024, by Jianjun Hu:
  First implementation.