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

Aleka Pappas apappas.enermodal at gmail.com
Wed Feb 13 08:22:02 PST 2008


I agree that CO sensor-controlled garage ventilation is standard practice
and the USGBC should not be allowing savings claimed from this control
method.  But we've submitted a number of projects for LEED with the Baseline
fans on all the time at 0.75 cfm/SF, and assumed the fans on about 1/4 of
this time in the Proposed Building, and the USGBC has allowed it.  We've
always stated our assumptions explicitly.  There should be a CIR to resolve
this, but so far it's been hard to find motivation on a project to spend the
200 bucks to force them to give the project 1 less LEED point.  It's
actually a huge issue for our high-rise condo and office projects....they
would be stretched to say the least to reach the 2 required points without
being able to claim these savings.  Which I think would be a good thing.

I've also worked with a few code jurisdictions around the country who
similarly allow savings from CO vent. control to calculate energy reduction
incentives.

If there's a USGBC person listening in, perhaps they could resolve the issue
with a freebie CIR?

Aleka

On Feb 13, 2008 7:37 AM, Fred Porter <FPorter at archenergy.com> wrote:

>  All,
> While I'm still on my first cup of coffee, and considering the PRM,
> general "baseline/budget/reference" model philosophy, and others' views on
> safe ventilation, another answer would be the default "baseline" =
> "proposed" operation and equipment, where the PRM does not specifically
> state a baseline. (You could still take credit for a premium efficiency fan
> motor.)
>
> I certainly suspect that savings have been granted to parking garage "DCV"
> by lenient reviewers, but it has not surfaced in a CIR.  Of course,
> clients might think it tacky of us to ask for stricter limitations and
> reduced savings and points in a CIR they pay for, which is a problem with
> the process. The fact that the baseline is unclear to experienced EA Cr1/PRM
> modelers says a lot, since there must be a couple million sf of
> ventilated parking garages rated or in the pipeline.
>
> Oh yeah, and what about those heated parking garages under every "green"
> office and resort hotel?
>
> And as far as "substituting" the cooling tower fan during summer; I would
> think drawing air through the garage with the CT fan would add some constant
> load to, or reduce the flow through, that fan, partially offsetting savings
> from turning off the garage fan (which would have operated at a low load
> factor if controlled by the typical sensor).
>
> Off to work;
> Fred
>
>
> >>> "Fred Porter" <FPorter at archenergy.com> 2/12/2008 2:27 PM >>>
> >>> "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?
>
>
> _______________________________________________
> Bldg-sim mailing list
> http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org
> To unsubscribe from this mailing list send  a blank message to
> BLDG-SIM-UNSUBSCRIBE at ONEBUILDING.ORG
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/attachments/20080213/6b1a56e1/attachment-0001.htm>


More information about the Bldg-sim mailing list