Chilled Water System – Staging Sequence Between Chillers and Primary Pumps

Objective/ Method/Outcome

Objective: Determines if a sequencing error exists between chillers and primary pumps.

Method: Compares the total number of primary pumps operating to the total number of chillers operating for up to 3 primary pumps and 3 chillers. An insight is generated when a mismatch occurs for greater than the defined daily threshold. Avoidable Cost and Potential Savings are determined by calculating unnecessary pump energy consumption.

Outcome: This rule generates an insight.

Description

Reference: ASHRAE Guideline 36-5.20.6.13 This rule determines If the number of operating pumps matches the number of running chillers. This rule is applicable for a group of chillers and associated pumps. Free cooling is an exception. This rule is part of the CopperTree Standard rule-set.

Default Priority

High

Diagnosis

1. Check whether the pumps and chillers are running in auto or manual mode.

2. Inspect the MCC panel of the concerned pumps and the starter panel of the chillers.

3. Ensure the relay panels within the concerned DDC are functioning properly.

Message

Improper staging sequence between chillers and primary pumps. Review and modify the sequence of operations.

Rule Template

Insight Type: Fault Detection

Trigger Type: Active High

Notes

1. Expected values for “Pump Status” inputs are “0” or “1”.

2. Expected values for “Chiller Status” inputs are “0” or “1”.

3. 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. – Pump Rating [HP]: 10

Const. – Electricity Rate [$/kWh]: 0.1

Const. – Weeks of Operation: 26