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

ParameterExpression Block Series NumberDescriptionDefault Value (Units)
Max Cycles per Day7The acceptable number of unit status changes. Anything more than that time is considered a fault.6 (Cycles per day)