Chilled water supply temperature control is poor

Objective/Method/Outcome

Objective: Determines if the temperature control of chiller is poor.

Method: Compares the actual temperature of the Chilled Water Supply and the setpoint and checks if it is greater than the dead band for more than the appropriate amount of time during operational hours.

Outcome: Triggers an Integrity KPI insight.

Applicable System

CWS

Description

Determine the error severity of a chilled water temperature control system in degree*hours.

This rule is part of the CopperTree Standard rule-set.

Calculate the severity metric based on the absolute difference between the water temperature and the water temperature setpoint deadband while the water temperature is outside of the deadband during scheduled hours.

Diagnosis

1. Issue with control loop. Review and modify controller tuning parameters.
2. Automatic setpoint control has been overridden. Revert setpoint back to automatic control.
3. Input sensor(s) faulty or miscalibrated. Verify input sensor(s) operation.

Message

The chilled water supply temperature has deviated from the setpoint for more than 10 degree*hours per week while the system is enabled. Review controller tuning parameters.

Rule Template

Insight Type: Integrity KPI

Trigger Type: Active High

Default Priority

Medium

Logic

Inputs

Input	Unit	Tags	Description
Chilled Water Supply Temperature	°C/ °F	Chilled Water Supply Temperature	The recorded water temperature
Chilled Water Supply Temperature Setpoint	°C/ °F	Chilled Water Supply Setpoint	The water temperature setpoint
Status		Chilled Water System Enabled, Chiller Status	To detect if CWS is operational
Const. – Temperature Threshold	°C/ °F		To minimum temperature deviation from setpoint beyond which an insight would be generated
Const. – Acceptable Weekly Threshold	°*hr
Days of operation annually			Days per year the system is operational
Cost per Degree*Hour	$

Notes

CTL generated:

CHWST Severity KPI