Determine if chiller is operating when OAT is below chiller enable set point

Applicable Systems

  • Primary: CHLR

Objective/Method/Outcome

  • Objective: Determine if the chiller is operating when cooling may not be required.
  • Method: Check if chiller is running when outdoor air temperature (OAT) is greater than user defined threshold.
  • Outcome: An insight is generated when the chiller is ON for more hours per week than the allowed threshold

Logic

The logic flow starts by normalizing all the inputs to 5 min intervals. Block(26) determines if the chiller is on. Block(7) determines if the outdoor temp is below threshold If both (26) and (7) are true then sum the time per day and record this in CTL. Sum the times both (26) and (7) are on per week and compare this to the threshold

while(chiller = On and OAT < threshold) {
   CTL = agg (daily) with # of hours
   if agg (weekly) > threshold  then generate insight
   }

Determine if chiller is operating when OAT is below chiller enable set point

Description / Method

Determine if the chiller is operating when a heating plant may not be required. {BLR} Check if the chiller is enabled below the desired OAT threshold.

  1. Verify heating plant sequence of operation.
  2. Enable Automatic control.

Message

The chiller has been operating for more than 4 hours a week while the OAT is below its enable set point of 30 degrees. Verify heating plant sequence of operation.

Notes

Rule Template Type

  • Insight Type: Fault Detection
  • Trigger Type: Low

Default Priority

Medium

Inputs

InputsUnitsTagsDescription
Chiller Status0/1 or Ampsblr, statusChiller status
Chiller ON Threshold0/1 or Amps Threshold that indicates chiller is on
OAT°C/°Fsensor, outside, air, tempOutdoor air temperature

Constants

ConstantUnitsDefault ValueDescription
Minimum OAT Threshold [deg]°C/°F14Outdoor temperature threshold for chiller operation
Weekly Acceptable Hourshours4Number of hours chiller is allowed to run when temp is below OAT

Output Calculated Trend Logs

Output CTLUnitsFrequencyDescription
Daily hours chiller operating below OAT thresholdhoursdailyHours per day that chiller is operating below temp threshold