Enhanced Prioritization – Cooling Tower Cycling Excessively

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

Logic for determining Cooling Tower is cycling excessive

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