Determine if system occupancy is changing state too frequently

Applicable Systems

  • Primary: AHU, RTU, MUA, ERV, BLR, CHLR

Objective/Method/Outcome

  • Objective: Determine if operational status controlled by an on/off signal is changing status at a very high rate.
  • Method: Check the number of times the equipment status has cycled on/off over the course of a day.
  • Outcome: An insight is generated if the number of status changes is more than 6 cycles per day.

Logic

Sum daily(numberOfStatusChanges)
Determine if system occupancy is changing state too frequently

Notes

Input should be binary, preferably with a COV trend log. The primary equipment short cycling rule allows for less status changes per day than the secondary equipment short cycling rule.

Inputs

  • Occ ( Binary Trend Log)*
  • The occupancy trend log should be COV, to get the greatest value for this rule.

Parameters

Parameter Expression Block Series Number Description Default Value (Units)
Max Cycles per Day 7 The acceptable number of unit status changes. Anything more than that time is considered a fault. 6 (Cycles per day)