[Bldg-sim] Garage Ventilation and LEED Credit EA-1

[Mitchell Dec]

On the topic of garage ventilation...
 
What if the garage exhaust fans could be turned off for a portion of the year. In my case, I have a project that is looking to use the cooling tower to provide half of the exhaust when the cooling tower is on. If the exhaust fans were staged off when the cooling tower was on, would it be reasonable to claim fan energy reduction using hourly report data and suibmit as an exceptional calc?
 
Thanks,
Mitch
 

 

Mitchell J. Dec
Senior Energy Analyst
LEED® Accredited Professional

 <http://www.glumac.com/> 

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Thinking. Inside the building.
http://www.glumac.com/ 

 

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org]On Behalf Of Fred Porter
Sent: Tuesday, February 12, 2008 1:28 PM
To: Michael Tillou; bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Garage Ventilation and LEED Credit EA-1


>>> "Michael Tillou" <michael.tillou at gmail.com> 2/12/2008 1:31 PM >>>

Does anyone know if USGBC is allowing credit for CO Control of parking garage ventilation?  If anyone has any experience with successfully getting credit for this efficiency measure can you please let me know.  I am curious what is considered a reasonable baseline.
 

Dear Colleagues;
Short answer: I sure hope not!
 
I very much believe the "reasonable" baseline is CO sensors, so you would schedule the airflows (thus power, if all goes correctly in model land) proportional to some assumed activity schedule. (There is a good summary of what those flows might be in an ASHRAE Jrnl that's about ten years old but on the AJ website.)  CO control is pretty much SOP; I think the IMC, or one of the codes around here, went up to 1.25 cfm/sf constant venting unless CO sensors are used; pretty much assuring everyone uses sensors. There may still be a code req'd floor on the min vent rate even w/sensors. And, in all but the smallest garages, staged fans are typical. MAYBE someone could invent some rationale that if there were some long ducts serving a deep garage, then VSD fans might have a SLIGHTLY lower operating W/cfm and closer tracking of actual req'd dilution air. But not by much.
 
Sure it sounds like "DCV" and the PRM sez we can take credit for that; but we would be creating a baseline considerably worse than typical construction, even 5-10 year old construction. And certainly we can't use 0.7 W/cfm in this baseline. This is why when we get proposals from savvy clients, they specify bldg maximum Btu/sf or kWh/sf or emissions/sf; not some "savings" vs. an artificial baseline. 
 
Fred
 
P.S. Today's Puzzler: What ASHRAE PRM category does a heated parking garage fall into? Does it matter if the heating capacity is more than the semi-conditioned space Btuh/sf rate? 


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