Enhanced Prioritization – Chiller operating below lockout temperature

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

  1. Chiller plant operating below OAT lockout. Verify cooling plant sequence of operation.
  2. 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

Logic used for determining if chiller is operating below lockout temperature

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