Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Validation

Collection of validation models

Information

This package contains validation models for the classes in Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.

Note that most validation models contain simple input data which may not be realistic, but for which the correct output can be obtained through an analytic solution. The examples plot various outputs, which have been verified against these solutions. These model outputs are stored as reference data and used for continuous validation whenever models in the library change.

Package Content

Name	Description
WaterLevel	Validation sequence of cooling tower make-up water control
WithWSE	Validation sequence of controlling tower of a plant with waterside economizer
WithoutWSE	Validation sequence of controlling tower of a plant without waterside economizer

Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Validation.WaterLevel

Validation sequence of cooling tower make-up water control

Information

This example validates Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.WaterLevel.

Modelica definition

Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Validation.WithWSE

Validation sequence of controlling tower of a plant with waterside economizer

Information

This example validates Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Controller. It demonstrates the cooling tower control of a less coupled chiller plant that has two chillers with waterside economizer.

• At beginning, the water level is lower than the minimum thus the tower starts to adding water (yMakUp). When the water level becomes greater than the maximum, it stops adding water at 1500 seconds.
• The plant is enabled to waterside economizer mode at 540 seconds. The lead tower cell becomes enabled when there is any condenser water pump enabled.
• After 300 seconds (chaTowCelIsoTim) at 840 seconds, it turns on the leading cell.
• The tower fan speed is controlled under the waterside economizer only mode. The direct-acting PID controls the chilled water supply temperature at setpoint.
• At 1440 seconds, the chiller 1 becomes enabled. Thus, the tower fan speed is then controlled under the integrated operation mode. However, before switching to the integrated operation mode, the fan hold its speed at the maximum. According to the vector towCelOnSet, which specifies number of cells at each plant stage (staVec), two tower cell should be enabled. Thus, after chiller 1 being enabled at 1440 seconds, when the 300 seconds is passed (chaTowCelIsoTim), the cell 2 become enabled at 1740 seconds.
• Both cells run at the maximum speed till 2040 seconds, the fan speed is then controlled under integrated mode.

Modelica definition

Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Validation.WithoutWSE

Validation sequence of controlling tower of a plant without waterside economizer

Information

This example validates Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.Controller. It demonstrates the cooling tower control of a less coupled chiller plant that has two chillers without waterside economizer.

• At beginning, the water level is lower than the minimum thus the tower starts adding water (yMakUp). When the water level becomes greater than the maximum, it stops adding water at 1500 seconds.
• The plant is enabled in chiller mode at 360 seconds. The chiller 1 becomes enabled and the lead cooling tower cell becomes enabled at 372 seconds.
• After 300 seconds (chaTowCelIsoTim) at 660 seconds, it turns on the leading cell.
• The tower fan speed is controlled based on the control of condenser water return temperature ( Buildings.Controls.OBC.ASHRAE.G36.Plants.Chillers.Towers.FanSpeed.ReturnWaterTemperature.Controller).
• At 1560 seconds, the plant state setpoint changes from 1 to 2. According to the vector towCelOnSet, which specifies number of cells at each plant stage (staVec), two tower cell should be enabled. After 300 seconds (chaTowCelIsoTim) at 1860 seconds, it turns on the cell two.

Modelica definition