modelCellsNumber

Validation sequence of identifying total number of enabling cells

Information

This example validates Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Staging.Subsequences.CellsNumber.

It shows the calculation of total number of tower cells when the plant is operating in scenarios including:

1 chiller only,
1 chiller and waterside economizer together,
in the chiller staging process but before staging up the tower cells,
in the chiller staging process after staging up the tower cell.

Note in this example, the total number of tower cells is specified according to following table. It is defined by the parameter towCelOnSet[totSta].

Plant stage	Index	Number of enabled cells
0	1	0
WSE	2	2
1 chiller	3	2
1 chiller + WSE	4	4
2 chillers	5	4
2 chillers + WSE	6	4

The example shows following process:

Before 300 seconds, the chiller stage equals to its setpoint (1) and the economizer is not enabled. Thus the plant stage index is 3. The total number of tower cells should be towCelOnSet[3], which is 2.
Between 300 seconds and 840 seconds, the chiller stage still equals to its setpoint (1), but the economizer is enabled. Thus the plant stage index is 4. The total number of tower cells should be towCelOnSet[4], which is 4.
Between 840 seconds and 1500 seconds, the economizer is disabled and the chiller stage keeps equal to its setpoint at 1. Thus the plant stage index is 3 and the total number of tower cells should be towCelOnSet[3], which is 2.
Between 1500 seconds and 2700 seconds, the economizer keeps disabled. However, the chiller stage setpoint changes to be different from its current stage index. This means the plant is in the chiller staging process. Since the input uTowStaCha is false, it means the staging process has not yet into the subprocess to staging up tower cells. Thus the plant stage is still 3 and the total number of tower cells should be towCelOnSet[3], which is 2.
After 2700 seconds, the economizer keeps disabled and it is still in the chiller staging process. However, the input uTowStaCha becomes true, it means the staging process requires staging up tower cells. The plant stage becomes 5. The total number of tower cells should be towCelOnSet[5], which is 4.

Components

Type	Name	Description
Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Staging.Subsequences.CellsNumber	enaTowCel	Find number of enabling cells
Buildings.Controls.OBC.CDL.Logical.Sources.Pulse	wseSta	Water side economizer status
Buildings.Controls.OBC.CDL.Reals.Sources.Ramp	chiStaGen	Generate chiller stage
Buildings.Controls.OBC.CDL.Conversions.RealToInteger	chiStaSet	Chiller stage setpoint
Buildings.Controls.OBC.CDL.Integers.Sources.Constant	curChiSta	Current chiller stage
Buildings.Controls.OBC.CDL.Logical.Sources.Pulse	booPul2	Boolean pulse
Buildings.Controls.OBC.CDL.Logical.Not	StaTow	Stage tower cells
Buildings.Controls.OBC.CDL.Logical.Sources.Constant	con	Constant false
Buildings.Controls.OBC.CDL.Logical.Sources.Constant	con1	Constant false

Revisions

September 12, 2019, by Jianjun Hu:
First implementation.