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NC-v4 EAp2:Minimum energy performance

Reheating more than 30% at the VAV

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Dave Hubka
Practice Leader - Sustainability
EUA
LEEDuser Expert
510 thumbs up

I am becoming involved with a project that is being designed to reheat more than 30% of the max cooling airflow rate at the VAV box. 

Section 6.5.2 of 90.1 does not allow reheating more than 30% of the zone's design peak supply rate. 

Section 6.5 is prescriptive not mandatory. 

My guess is that the design can reheat more than 30%. Baseline energy model accounts for reheating no more than 30% while the Proposed energy model is accounts for the as-designed building. 

is this correct?

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Cory Duggin
Senior Energy Wizard
TLC Engineering Solutions
LEEDuser Premium Member
44 thumbs up

Wed, 09/18/2024 - 14:29

What is the rationale for reheating more than 30% of peak design airflow?  Most of the time the reason we do it is for minimum ventilation or code required min ACH.  The example I'm thinking about is a conference room that say needs 50% min supply air to hit the minimum 62.1 vent requirements, so it reheats more.
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Dave Hubka
Practice Leader - Sustainability
EUA
LEEDuser Expert
510 thumbs up

Wed, 09/18/2024 - 15:28

Hi Cory, thanks for your response.  Our rationale to reheat more than 30% of peak design airflow is to provide minimum code ventilation during worst-case condition (i.e. peak space occupancy). This aligns with an exception listed within 90.1. You are correct, this issue arises with conference rooms.   

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