Objective/Method/Outcome
Objective: Determines if the chiller is overcooling for more than the acceptable amount of time.
Method: Compares the chilled water supply temperature to the chilled water supply temperature setpoint. When the temperature is below the setpoint, the chiller is overcooling and if it is overcooling for more than the acceptable amount of time (4 hours by default), insight is triggered.
Outcome: Triggers an insight if the chiller is overcooling for more than the acceptable amount of time.
Applicable System
CWS
Description
Monitors chilled water supply temperature while chiller is active to determine if chiller is overcooling the water, resulting in excess energy consumption.
This rule is part of the CopperTree Standard rule-set.
Default Priority
Medium
Diagnosis
Review chilled water system programming.
Message
Chiller may be overcooling, as CHW supply temperature is below threshold.
Rule Template
Insight Type: Fault Detection
Trigger Type: Active High
Logic
Inputs
| Input | Unit | Tags | Description |
|---|---|---|---|
| Chiller Status | Chiller Status, Chiller Command | The recorded chiller status | |
| Threshold – Weekly Hours of Faulty Operation | The weekly acceptable hours of fault above which an insight is triggered | ||
| Chilled Water Supply Setpoint | °F/°C | Chilled Water Supply Temperature Setpoint | The recorded setpoint |
| Chilled Water Supply Temperature | °F/°C | Chilled Water Supply Temperature | The recorded CWS temperature |
| CHW Supply Temperature Deadband | °F/°C | The allowable deviation from setpoint |
Notes
Default Values:
- CHW Supply Setpoint Deadband: 2°F or 1°C
- Threshold – Hours of Faulty Operation: 4
