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Must have VAV system for Option 1?

Dave Intner

Firmitas Architecture & Planning

LEEDuser Basic Member

65 thumbs up

February 8, 2010

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Erik Dyrr

Director, Sustainable Buildings and Operations

KEMA

LEEDuser Basic Member

58 thumbs up

Thu, 02/11/2010 - 03:19

Can you inform us of the type of air handling you do have? The modulating aspect would still apply. If single zone units, then it is an on/off scenario.

Dave Intner

Firmitas Architecture & Planning

LEEDuser Basic Member

65 thumbs up

Wed, 02/17/2010 - 17:24

Thanks for your reply, Erik. The project is utilizing constant volume packaged gas/electric units, however, the units are specified with a variable frequency drive (VFD) which will allow them to maintain a constant airflow to the space as the filters load up (and their static pressure drop increases). The higher filtration for this project is a result of the space being an OSHPD 3 occupancy. By an ‘on-off’ scenario, are you talking about the fan shutting off when there is no demand? Due to the code's ventilation requirements, the fan will run when the space is occupied, continuously.

Erik Dyrr

Director, Sustainable Buildings and Operations

KEMA

LEEDuser Basic Member

58 thumbs up

Wed, 02/17/2010 - 18:07

With a typical constant volume system I don't know how the project could meet the requirements of modulating the airflow. The only option I can think of is to modify the system with zone dampers controlled by occupancy or CO2 sensors. But this is not likely a feasible option.

Dave Intner

Firmitas Architecture & Planning

LEEDuser Basic Member

65 thumbs up

Thu, 02/18/2010 - 16:46

Thanks Erik. It seems we're in a situation where code ventilation requirements are trumping opportunities for efficiency.

Christine Beaton

BR+A Consulting Engineer

LEEDuser Basic Member

7 thumbs up

Wed, 03/16/2011 - 15:45

The question I have is are they asking for there to be VAV flow. I read the CPG to say that drives are required for VAV systems not that VAV systems are required. Based on this, can it be argued that constant volume systems are exempt from this requirement? We've gotten this credit when our motors were exempt for being too small and our systems exempt for being chilled water cooling or on a base building VAV AHU (efficiency requirement). Why not this? We're not installing a constant volume system, just reutilizing one in a renovation. Interested in people's thoughts on this. Worse comes to worse, we can just submit and find out but looking for others' experience.

Paul Conrad

Energy Engineer

CLEAResult Consulting

LEEDuser Basic Member

222 thumbs up

Thu, 03/31/2011 - 14:25

Christine, I've never attempted to submit in that manner, but with how difficult GBCI reviewers can be on this particular credit, I have my doubts that it would be accepted. If you do submit, please share with us the review comments, so that we can better understand how GBCI feels about this particular approach. Sorry that I can be of more help, Paul