G.3.1.3.14

Francesco Passerini

engineer

LEEDuser Basic Member

65 thumbs up

April 10, 2013

As baseline model I have to model a System 6. Paragraph G3.1.3.14 states: “… Minimum volume setpoints for fan-powered boxes shall be equal to 30% of peak design flow rate or the rate required to meet the minimum outdoor air ventilation requirement, whichever is larger…” Is that volume considered as the sum of the air flow coming from the main AHU and of the air flow recirculated from the zone directly through the fan-powered box? Shall the “peak design flow rate” be the maximum value throughout the year (i.e. considering both summer conditions and winter conditions)? Best Regards

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Marcus Sheffer

LEED Fellow

7group / Energy Opportunities

LEEDuser Expert

4454 thumbs up

Tue, 04/16/2013 - 19:26

No in peak cooling it all comes from the primary air flow associated with the air handler. The peak design flow rate is based on the summer cooling conditions. For example, if the peak cooling is 1000 cfm, the minimum is 300 cfm and the zone fan delivers 500 cfm (at 0.35 W/cfm) so the total air flow in heating mode is 800 cfm.