Objective/Method/Outcome
Objective: Determines if Cooling Tower is cycling states using Analog and Binary trend logs
Method: Normalizes the analog and binary samples and checks to see if they cycle more than the acceptable amount of time. For Cooling Tower cycling more frequently, a weekly property impact is calculated, an Urgency score depending on the severity of cycling and the potential savings calculating by subtracting the cost of excessive cycling and the cost of buying new equipment.
Outcome: Triggers an insight, urgency score assigned, weekly proper impact, and potential savings calculated.
Description
Analyzes equipment state changes using Analog or Binary trend log, triggering an insight when daily cycles exceeds a threshold.
This rule is part of the CopperTree Standard rule-set.
Default Priority
Medium
Diagnosis
Check and revise programming and sequence of operation to prevent unnecessary equipment cycling.
Message
Cooling tower is cycling more often than expected.
Rule Template
Insight Type: Fault Detection
Trigger Type: Active High
Logic
Inputs
| Input | Unit | Tags | Description |
|---|---|---|---|
| Equip Command Or Amperage | Cooling Tower Fan Status, Cooling Tower Fan Command | The recorded cooling tower fan status | |
| Threshold – PropertyImpact Weekly | The minimum property impact that can trigger an insight | ||
| Threshold – UrgencyScore WeeklyMax | The maximum urgency score that can the rule can assign | ||
| Cost to Replace Equipment | $ | The estimated cost of replacing the equipment | |
| Expected Equipment Lifetime | Years | The expected lifetime of the equipment in use | |
| Annual Days of Operation | The annual days the equipment is operational | ||
| Threshold – Analog Cycle Delta | The minimum change in analog reading that can trigger insight | ||
| Threshold – Daily Cycles | The minimum number of cycles that can trigger an insight |
Notes
Urgency Score is a measure of how urgent the fault is and a high score denotes critical adverse impact on the equipment. Urgency Score is scaled so that if the number of cycles is equal to or less than the Daily Cycles Threshold, the score is 0. If the number of cycles per day is twice that of the Daily Cycles Threshold, the score is 100. The maximum score of the week is used to trigger the Insight. Property Impact is calculated as the number of days during the week where the cycle count was higher than threshold (expresses in percent of total days being monitored in the week)
Default values for constants:
- Threshold – Analog Cycle Delta: 1
- Threshold – PropertyImpact Weekly: 14
- Threshold – UrgencyScore WeeklyMax: 30
- Threshold – Daily Cycles: 20
