Cooling is insufficient
Objective/Method/Outcome
Objective: Determines if cooling is sufficient.
Method: Compares the cooling command to the valve error threshold to determine if the valve is at 100%. Determines if SAT is above the sum of the setpoint and the acceptable deadband. This is used to filter the amount of time temperature is above the acceptable range while the cooling command is at 100%. Another filter is applied to determine if the AHU was active during these hours. This is used to calculate the weekly hours of fault operation.
Outcome: Calculates an Integrity KPI and triggers an insight.
Description
Monitor valve position TL and determine if the valve is constantly at 100% while SAT is not satisfying setpoint requirements.
This rule is part of the CopperTree Standard rule-set.
Default Priority
Medium
Diagnosis
- Check temperature sensor calibration.
- Cooling may be insufficient.
Message
Cooling may be insufficient as valve is 100% open while SAT can not satisfy setpoint requirements.
Rule Template
Insight Type: Fault Detection
Trigger Type: Active High
Logic
Inputs
| Input | Unit | Tags | Description |
|---|---|---|---|
| AHU Status | Discharge Air Fan Status, Discharge Air Fan Command | The recorded status of air handing unit | |
| Threshold – Weekly Hours | The minimum hours of fault that can trigger an insight | ||
| SAT | Discharge Air Temperature | The recorded SAT | |
| SAT SP | Discharge Air Temperature Setpoint | The preset/ideal SAT | |
| Temperature Setpoint Deadband | ° | The allowable deviation from temperature setpoint | |
| Cooling Valve | Discharge Air Cooling Command | The recorded Cooling Command |
Notes
Default Thresholds:
- Temperature Setpoint Deadband: 2°
- Threshold – Weekly Hours: 8