Energy recovery is not fully utilized in heating season

Objective/ Method/Outcome

Objective: Determines if the exhaust air Energy Recovery Wheel is being effectively utilized during the heating season.

Method: Compares the Exhaust Air Temperature, Outdoor Air Temperature, and Supply Air Temperature to the Energy Recovery Wheel status. If the Energy Recovery Wheel is inactive while conditions are suitable for warmer exhaust air to raise the temperature of cooler outdoor air, the hours of faulty operation are calculated. Avoidable Cost and Potential Savings are calculated based on the Electricity Rate.

Outcome: This rule generates an insight if the Weekly Hours of Faulty Operation exceeds the acceptable weekly threshold.

Description

Reference: ASHRAE90.1-6.5.6.1

This rule is applicable for exhaust air heat recovery. In the cooling season, cooler exhaust air can be used to reduce hot outdoor air temperature before it’s exhausted outside.

This rule is part of the CopperTree Standard rule-set. (Aliased Celsius)

Default Priority

Medium

Diagnosis

1. Related sensor(s) error

2. Review control sequence

Message

Energy recovery is not fully utilized in heating season.

Rule Template

Insight Type: Energy

Trigger Type: Active High

Notes

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

2. Expected values for “Supply Fan Speed” inputs are “100” if they are constant speed fans or not available.

Default Values:

Const. – Threshold – Weekly Hours of Faulty Operation: 14

Const. – Heat Recovery Activate Delta-T Threshold [*C]: 2

Const. – AHU Rated CFM: 10000

Const. – Electricity Rate($/kWh): 0.1

Const. – Weeks of Operation: 26

CTLs:

Energy recovery not utilized in heating mode – Weekly Hours of Faulty Operation (KPI)

Energy recovery not utilized in heating mode – Hours of Faulty Operation (CUSUM)

Energy recovery not utilized in heating mode – Avoidable Cost [$]

Energy recovery not utilized in heating mode -Potential Savings [$]