Applicable Systems
- Primary: CHLR
Objective/Method/Outcome
- Objective: Determine chiller temperature performance score
- Method: Analyze the chilled water supply temperature (CHWST) control system using the amount of time the chilled water supply temperature is within deadband while the chiller is on.
- Outcome: A KPI score is generated on a daily basis while a ‘Bad Score’ insight can be produced weekly when a score reaches below 60% for the week.
Logic
- Input normalized water temperature and its corresponding temperature set points.
- With a temperature deadband constant, check if the deviation is out of range.
- If deadband is exceeded and the chiller is active, pass a bad score. If within deadband and the chiller is active, pass a good score.
- Aggregate and average score daily and weekly; generate the daily KPI score in a CTL.
- If the weekly score is below an acceptable threshold, generate an insight.
while(chlr sts == 1) { if( |CHWST - CHWST SP| > Deadband Const. ) { Award performance KPI score 0% } else { Award performance KPI score 100% } average performance KPI score daily average performance KPI score weekly }
Description / Method
Determine the performance index of a chilled water supply temperature (CHWST) control system using the amount of time the chilled water supply temperature is within deadband (SP ± 1.5) while the chiller is on. {CHLR}
Diagnosis / Recommended Action
- Issue with control loop. Review and modify controller tuning parameters.
- Chilling water not available. Verify Chiller plant operation.
- Automatic setpoint control has been overridden. Revert setpoint back to automatic control.
- Input sensor(s) faulty or miscalibrated. Verify input sensor(s) operation.
Message
The chiller’s temperature performance KPI score is below 60% for the week. Review control loop tuning parameters.
Notes
This rule will not generate an insight unless the user changes the Trigger Block to “Insight – Bad Score”.
This rule is designed for °C inputs by default.Default Constants:
- Const. – Acceptable Weekly Score [%]: 60
- Const. – Chilled Water Supply Deadband [°C]: 1.5
- (Recommended default Deadband for Fahrenheit is 3 °F)
CTL Generated:
- CHWST Performance KPI
Rule Template Type
- Insight Type: Integrity KPI
- Trigger Type: Active High
Default Priority
Low
Inputs
Inputs | Units | Default Value | Tags | Description |
---|---|---|---|---|
Chilled Water Supply Temperature | °C | sensor, leaving, chilled, water , temp | Chiller water supply temperature from chiller | |
Chilled Water Supply Temperature Setpoint | °C | sp, leaving, chilled, water, temp | Chiller water supply temperature set point | |
Chiller Status | cmd|sts | Chiller status | ||
Const. – Chilled Water Supply Temperature Deadband | °C | 1.5 | The acceptable temperature deviation from setpoint | |
Const. – Acceptable Weekly Score | % | 60 | The lowest acceptable weekly KPI score |
Output Calculated Trend Logs
Output CTL | Units | Description |
---|---|---|
CHWST Performance KPI | % | Daily generated performance KPI score |