Objective/ Method/Outcome
Objective: Determines if the cooling setpoint is too low while the zone is unoccupied.
Method: Compares the Unoccupied Cooling Setpoint to the Occupied Cooling Setpoint and the recommended ASHRAE Temperature Setpoint Setback. If the Unoccupied Cooling Setpoint is below this recommendation the hours of faulty operation are calculated. Avoidable Cost and Potential Savings are calculated based on the defined Electricity Rate.
Outcome: This rule generates an insight if the Weekly Hours of Faulty Operation exceeds the acceptable weekly threshold.
Description
Reference: ASHRAE90.1-6.4.3.3.2
This rule determines if unoccupied cooling temperature setpoint is too low. Control sequence shall have unoccupied cooling setpoint as least 2.8°C above the occupied cooling set point.
This rule is part of the CopperTree Standard rule-set. (Aliased Celsius)
Default Priority
Medium
Diagnosis
Update unoccupied cooling setpoint
Message
Unoccupied cooling setpoint is too low.
Rule Template
Insight Type: Fault Detection
Trigger Type: Active High
Notes
1. Only one “Airflow”, [LPS] or [CFM] is needed.
2. The input(s) that is(are) not used should be set to “0”.
Default Values:
Const. – Temperature Setpoint Setback [°C]: 2.8
Const. – Acceptable Weekly Hours of Faulty Operation [hours]: 8
Const. – Electricity Rate($/kWh): 0.1
Const. – Weeks of Operation:52
CTLs:
Unoccupied Cooling SP is too low – Weekly Hours of Faulty Operation (KPI)
Unoccupied Cooling SP is too low – Hours of Faulty Operation (CUSUM)
Unoccupied Cooling SP is too low – Avoidable Cost [$]
Unoccupied Cooling SP is too low – Potential Savings [$/Year]
