Objective/Method/Outcome
Objective: Determines if the chiller is operational when the temperature of OAT is below the lockout temperature
Method: Checks the chiller is enabled and determines the moving average of OAT. If the chiller is enabled when the 4 hour moving average of the system is above the chiller enable setpoint, an insight is triggered and the potential savings is projected by calculating the hours of fault and the cost of fault per hour.
Outcome: Triggers an insight, calculates the potential savings and the weekly energy impact.
Description
Determines if the chiller is operating when the cooling plant may not be required, and calculates Potential Savings and Energy Impact.
This rule is part of the CopperTree Standard rule-set.
Default Priority
Medium
Diagnosis
- Chiller plant operating below OAT lockout. Verify cooling plant sequence of operation.
- Automatic control has been overridden. Revert equipment back to automatic control.
Message
The chiller has been operating while OAT is below its lockout temperature. Ensure that chiller enable is not overridden, then verify the sequence of operation.
Rule Template
Insight Type: Fault Detection
Trigger Type: Active High
Logic
Inputs
| Input | Unit | Tags | Description |
|---|---|---|---|
| Chiller Enable | Chiller Command, Chiller Status | The recorded status of the chiller | |
| Threshold – PotentialSavings Yearly | $ | The minimum potential savings per year that can trigger an insight | |
| Outdoor Air Temp | ° | Outdoor Air Temperature | The recorded outdoor air temperature |
| Estimated Weeks Of Cooling Operation | The estimated weeks the cooler is operational per year | ||
| Chiller Enable OAT Setpoint | °C/°F | The OAT that enables the chiller | |
| Threshold – Weekly Energy Impact | % | The minimum percentage of fault that can trigger an Energy Impact | |
| Cost per Hour of Operation | $ | The cost of fault per hour | |
| Chiller Rating | HP |
Input
Default values for constants:
- Potential Savings Yearly Threshold ($): 100
- Threshold – Weekly Energy Impact [%]: 30
- Chiller Enable OAT Setpoint (deg): 59°F or 15°C
- Estimated Weeks Of Chiller Operation: 26
