Determine supply air temperature performance KPI score

Applicable Systems

• Primary: AHU, RTU, MUA, ERV

Objective/Method/Outcome

• Objective: Determine supply air temperature performance score.

• Method: Analyze the performance index based on the total time the supply air temperature (SAT) is within the deadband during occupied hours.

• Outcome: A performance KPI CTL is generated on a daily basis while there are no insights. However, a user can change the trigger block to “Insight – Bad Score”, and an insight will be generated if the weekly score is below 60%.

Logic

• Input normalized supply air temperature and its correlating set point.
• Check if the deviation exceeds the threshold constant in degrees, and the building is active. An aggregated daily performance KPI is calculated based on the amount of time the temperature is within the deadband.
• If the Trigger Block is changed to “Insight – Bad Score” and the average weekly score is less than the acceptable weekly score, an insight is generated.

while(occ == 1)
   {
   if( |SAT - SAT SP| > Deadband Const. )
         {
         Award performance KPI score 0%
         }
   else
         {
         Award performance KPI score 100%
         }
   average performance KPI score daily
   average performance KPI score weekly
   }

Description / Method

Determine the performance index of a supply air temperature control system using the amount of time the supply air temperature (SAT) is within the deadband (SP ± 1.5 °C) while the unit is on. {AHU|RTU|MUA|ERV}

Diagnosis / Recommended Action

1. Issue with control loop. Review and modify controller tuning parameters.
2. Automatic setpoint control may have been overridden. Review temperature setpoint control.
3. Input sensor(s) faulty or miscalibrated. Verify input sensor(s) operation.
4. Chilled water not available. Verify chiller plant operation.
5. Heating water not available. Verify boiler plant operation.

Message

The supply air temperature KPI score is below 60% for the week. Review control loop tuning

Notes

This rule will not generate an insight unless the user changes the Trigger Block to “Insight – Bad Score”.
This rule is designed for °C inputs by default.Default Constants:

• Const. – Acceptable Weekly Performance Score [%]: 60
• Const. – Supply Air Temperature Deadband [°C]: 1.5
  • (Recommended default deadband for Fahrenheit is 3 °F)

CTL Generated:

• SAT Performance KPI

Rule Template Type

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

Default Priority

Low

Inputs

Inputs	Units	Default Value	Tags	Description
Supply Air Temperature	°C		sensor, discharge, air, temp	Supply air temperature measured records
Supply Air Temperature Set Point	°C		sp, discharge, air, temp	Supply air temperature set point for the system
Status			cmd|status, discharge	Unit status
Const. – Supply Air Temperature Deadband	°C	1.5		The acceptable supply air temperature change
Const. – Acceptable Weekly Score	%	60		The lowest acceptable weekly performance KPI score before generating an insight

Output Calculated Trend Logs

Output CTL	Units	Description
SAT Performance KPI	%	Score representing the amount of time the supply air temperature is within deadband, as a percentage