Chilled Water System – Condenser water supply temperature setpoint reset control is poor

Objective/ Method/Outcome

Objective: Determines if the chiller condenser water supply temperature setpoint reset is controlling poorly.

Method: The Proposed Condenser Water Supply Temperature is determined based on Wet Bulb Temperature and ASHRAE Standards then is compared with the Condenser Water Supply Temperature Setpoint and the defined temperature threshold. An insight is generated if this fault occurs for longer than the defined Weekly Faulty Hours Threshold.

Outcome: This rule generates an insight.

Description

Reference: ASHRAE90.1-G3.1.3.11 This rule determines if the condenser water supply temperature (cooling tower leaving temperature) is reset properly based on outdoor wet bulb temperature. CWST=WB+(10.02 – (0.24 × WB)) This rule is part of the CopperTree Standard rule-set.

Default Priority

Medium

Diagnosis

Reset condenser water supply temperature by outdoor web bulb temperature.

Message

Condenser water supply temperature is not reset properly.

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. – Weekly Faulty Hours Threshold [hr]: 8

Const. – Temperature Threshold [°]: 2