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?
Cory Duggin
Senior Energy WizardTLC Engineering Solutions
51 thumbs up
September 18, 2024 - 10:29 am
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.
Dave Hubka
Practice Leader - SustainabilityEUA
LEEDuser Expert
527 thumbs up
September 18, 2024 - 11:28 am
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.