Objective/ Method/Outcome
Objective: Determines if chiller is supplying chilled water at temperature setpoint outside of range.
Method: Compares the chilled water supply temperature setpoint to high and low temperature threshold limits and generates an insight when this fault occurs for greater than the defined daily threshold.
Outcome: This rule generates an insight.
Description
Reference: ASHRAE90.1-3.1.3.9 This rule detects periods when the cooling set point is below or above a threshold for over a specific duration. Unnecessary low chilled water supply temperature setpoint will reduce chiller performance and waste energy. High chilled water supply temperature setpoint will lead to insufficient cooling supply. Free cooling is an exception. This rule is part of the CopperTree Standard rule-set.
Default Priority
Low
Diagnosis
1. Revise cooling setpoint.
2. Review cooling setpoint reset control sequence.
Message
Cooling setpoint is out of operational limits. Please check and revert to normal value.
Rule Template
Insight Type: Fault Detection
Trigger Type: Active High
Notes
1. Expected values for “Chiller Status” inputs are “0” or “1”.
2. The input(s) that is(are) not used should be set to “0”.
Default Values:
Const. – Threshold – Daily Hours of Faulty Operation [hours]: 2
Const. – Threshold – Low Limit for Chilled Water Supply Temperature Setpoint [*C]: 7
Const. – Threshold – High Limit for Chilled Water Supply Temperature Setpoint [*C]: 12
