VAV Pressure Control Performance KPI

Applicable Systems

• Secondary: VAV

Objective/Method/Outcome

• Objective: Determine how well a Variable Air Volume unit’s Pressure Control is performing.

• Method: The KPI is determined by the deviation of the differential pressure (DP) from its set point, based on the total percentage of time a unit is within an allowable threshold (15%). Calculate the performance metric based on the total time the DP is not within the desired set point during occupied hours.

• Outcome: A performance KPI CTL is generated on a weekly basis.

Logic

while(occ == 1)
   {
   if( |DP - DP_SP|  > 15% DP_SP)
         {
         Award performance KPI score 0%
         }
   else
         {
         Award performance KPI score 100%
         }
   average performance KPI score daily
   average performance KPI score weekly
   }

Description / Method

The KPI is determined by the deviation of the differential pressure (DP) from its set point, based on the total percentage of time a unit is within an allowable threshold (15%). Calculate the performance metric based on the total time the DP is not within the desired set point during occupied hours.

Diagnosis / Recommended Action

1. Confirm VAV damper is operational
2. Check pitot tubes for blockage
3. Check controller tuning
4. Check scale range and functionality of DP sensor

Message

The VAV’s DP KPI score is below 60% for the date range selected.

Notes

The rule is disabled if the differential pressure is less than 50% of it’s set point. This is to prevent misleading scores.

Rule Template Type

• Insight Type: Integrity KPI
• Trigger Type: Active High

Default Priority

Low

Inputs

Inputs	Units	Default Value	Tags	Description
Differential Pressure			sensor, air, differential, pressure	Pressure system behaviour data
Differential Pressure Set Point			sp, air, differential, pressure	Pressure system set points
Occupied			occupied	Building occupancy