Objective/Method/Outcome
Objective: Determines if the VAV supply airflow control needs adjustment or calibration based on the airflow variance during occupied hours
Method: Calibrates the performance index and matrix based on the amount of time the airflow is outside the acceptable range during occupied hours.
Outcome: Generates an insight if AFLW is more than 15% of the setpoint for more than 4 hours
Applicable System
VAV
Desciption
Determine the performance index of a pressure control system using the amount of time the AFLW is not within the desired setpoint. Calculate the performance metric based on the total time the AFLW is not within the desired setpoint during occupied hours.
This rule is part of the CopperTree Standard rule-set.
Diagnosis
- Input sensor(s) faulty or miscalibration. Verify input sensor(s) operation.
- Automatic control has been overridden. Revert equipment back to automatic control.
- Issue with control loop. Review and modify controller tuning parameters.
- Primary air not available. Verify Air Handling Unit operation.
Message
Supply airflow deviates more than 15% from setpoint for more than 4 occupied hours per week.
Rule Template Type
Insight Type: Active High
Trigger Type: Integrity KPI
Default Priority
Low
Logic
Inputs
| Input | Unit | Tags | Decription |
|---|---|---|---|
| Airflow | Discharge Air CFM | The recorded the Airflow | |
| Airflow Setpoint | Discharge Air CFM Setpoint | The preset Airflow setpoint | |
| Occupancy | Room Occupied, Discharge Fan Command, Discharge Fan Status | ||
| Threshold – Acceptable Time Outside Range per Week | Hr | The acceptable amount of time the unit can be at fault without triggering an insight | |
| Threshold – Acceptable Airflow Variance | % | The percentage of allowed air flow variation from setpoint |
Notes
The rule is disabled if the AFLW is less than 50% of its set point in order to prevent misleading scores.
