See all forum discussions about NC-2009 EAp2
 Subscribe to new posts about NC-2009 EAp2 Post a new question aboutNC-2009 EAp2
See LEEDuser’s guidance on NC-2009 EAp2»
FAQs about EAp2 :

Our project has a large process load—75%. Despite our efforts to make an efficient HVAC design, the cost savings are minimal. What can we do to earn this prerequisite and be eligible for LEED certification? Is there any flexibility in how we model the p

Can SHGC be higher in the proposed than in the baseline model?

Our process load is higher than 25%. Do we have to justify that?

Do I need to justify the electrical and fuel rates I am using in my model?

Our local code references ASHRAE 90.1-2010. Should I use that for my documentation, or 90.1-2007?

Can I claim exterior lighting savings for canopy lighting even though a baseline model cannot include shading elements?

The project is built on a site with existing exterior lighting installed. How should this be accounted for?

Can mezzanines open to floors below be excluded from the energy model?

How do I provide a zip code for an international location?

For a project outside the U.S., how do I determine the climate zone?

For a project outside the U.S., how do I determine the Target Finder score?

Do hotel rooms need automatic light shut-off control?

How commonly are the 90.1 mandatory compliance forms submitted as part of EAp2/EAc1?

The Section 9 space-by-space method does not include residential space types. What should I use?

Can the Passive House Planning Package (PHPP) be used to energy model for LEED?

Is it acceptable to model a split-type AC with inverter technology compressor as a heat pump, like modeling VRF?

Can the Trace 700 'LEED Energy Performance Summary Report' by uploaded to LEED Online in lieu of the Section 1.4 tables spreadsheet?

A portion of our building envelope is historic. Can we exclude it from our model?

Which baseline HVAC system do I use if my building has no heating or air conditioning?

For an existing building, do I need to rotate the model?

View answers »

Forum discussion

NC-2009 EAp2:Minimum Energy Performance

G3.1.3.14

I am not sure that I am interpreting section G3.1.3.14 in the correct way. I am considering only one fan-powered box: Qp = primary air flow (variable) Qs = air flow relative to the fan in parallel VAV fan-powered box (constant) Qtot = Qp + Qs (variable) Condition 1.: Fans in parallel VAV fan-powered boxes shall be sized for 50% of the peak design flow rate Interpretation: Qs = Qp,max / 2 Condition 2.: Minimum volume setpoints for fan-powered boxes shall be equal to 30% of the peak design flow rate. Interpretation: Qp,min = 30% Qp,max Are the interpretations correct? Best Regards

0
Post a reply

You rely on LEEDuser. Can we rely on you?

LEEDuser is supported by our premium members, not by advertisers.

Go premium for $15.95  »

Profile picture for user sheffer
Marcus Sheffer
LEED Fellow
7group / Energy Opportunities
LEEDuser Expert
4454 thumbs up

Tue, 07/14/2015 - 13:14

The formulas are correct. The assumption that Qs is constant however, is not correct. See ASHRAE Handbook - HVAC Applications 2015 page 47.14 or other source for the operation of parallel fans.

Add new comment

To post a comment, you need to register for a LEEDuser Basic membership (free) or login to your existing profile.