[Equest-users] GBCI comments on DCV (Carol Gardner)

Karen Walkerman kwalkerman at gmail.com
Tue Jul 27 06:04:41 PDT 2010


Is anyone on this list-serve on the EA Credit 1 committee, or know someone
who is?  If the the GBCI or USGBC has changed the modeling requirements and
is only letting modelers know during the documentation review stage, I find
this very disturbing for a number of reasons.  It would be great if we can
get some straight answers on this from someone at one of these organizations
who actually knows what is going on.

I am happy to draft an email outlining concerns, but I don't know who to
send it to.  If anyone does, or would like to help me with this, please feel
free to contact me directly.

Thanks,

--
Karen Walkerman

On Tue, Jul 27, 2010 at 8:28 AM, Peter Worley <peter.worley at arup.com> wrote:

>  Sorry for what may seem like a dumb question...
>
>
>
> Why, if you're designing to ASHRAE 62.1, would you increase the outside air
> quantity beyond the minimums (unless required for lab exhaust, etc)?
>
>
>
> I have a project where the local code (referencing IMC 2003) requires a
> higher level of minimum ventilation than ASHRAE 62.1. I’ve therefore
> designed to this amount and modeled it in both my proposed and baseline
> cases. I can’t imagine that this will be problematic. Do you disagree?
>
>
>
> Thanks,
>
> Pete
>
>
>
>
>
> *Peter Worley*
>
> Mechanical Engineer
>
>
>
> 155 Avenue of the Americas  New York  NY  10013  USA
>
> *t* +1 212 229 2669  *d* +1 212 897 1339
>
> *f* +1 212 229 1056
>
> www.arup.com
>
>
>
> [image: ArupEmailLogo]
>
>
>
> *From:* Tom Serra [mailto:tserra at emoenergy.com]
> *Sent:* Monday, July 26, 2010 12:14 PM
>
> *To:* Karen Walkerman
> *Cc:* equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] GBCI comments on DCV (Carol Gardner)
>
>
>
> No documentation exists supporting the new method.  GBCI is pulling the
> "rating authority" card and implementing their own requirements.   I tried
> to argue my case that they are going against the procedure in ASHRAE, but
> they did not change their requirement.  I have expressed my opinion that a
> document should be posted on the website that shows this new requirement but
> I have yet to see anything new.  Otherwise you may be expecting savings from
> DCV that will be rejected and then the MEP or modeler will look foolish.
> They should have implemented a cut-off date for projects already in the
> system similar to the "District Thermal" change they made in May 2008.
>
>
> In reality the DCV will still result in energy savings but the paper design
> savings will be lost.  I believe GBCI and USGBC are trying to prevent
> "gaming" of the system.  A designer could grossly oversize the ventilation
> system and then gain tremendous savings by implementing DCV.  This new
> requirement forces the designer to pursue other ventilation strategies if
> they want to claim savings for DCV.  Unfortunately the only way we are
> learning of this requirement is through clarification questions.  This lack
> of communication is what really upsets me.
>
> The only solution that I see is that all spaces with demand control
> ventilation should be designed to ASHRAE 62.1 minimums.  Also, teams should
> not pursue the 30% increase ventilation credit.
>
> Thomas Serra
> Project Manager
> EMO Energy Solutions, LLC
> 3141 Fairview Park Drive, Suite 450
> Falls Church, VA 22042
> voice 703-205-0445 ex-113
> fax 703-205-0449
>
>
>  On Mon, Jul 26, 2010 at 11:22 AM, Karen Walkerman <kwalkerman at gmail.com>
> wrote:
>
> Can anyone find documentation requiring the baseline to use ASHRAE 62.1
> ventilation rates?  The table in EA Credit 1 under HVAC System Selection for
> the baseline design states:
>
>
>
> "Outdoor ventilation rates should be identical to the proposed case"
>
>
>
> There are no exceptions listed anywhere in the LEED documentation (I am
> currently looking at LEED 2009, but have reviewed this in the past under
> LEED 2.2).
>
>
>
> We have had DCV be approved in the past with no questions.
>
>
>
> --
>
> Karen
>
>
>
> On Mon, Jul 26, 2010 at 11:08 AM, Tom Serra <tserra at emoenergy.com> wrote:
>
>  I've had many comments.  They have changed their perspective as the
> rating authority and are requiring outside air treatment procedures that are
> outside of ASHRAE 90.1 section G procedures.  Typically design outside air
> volume is the same between the baseline and proposed, but if you are using
> DCV they now require you to model the baseline with the minimum ASHRAE 62.1
> volume.  So, if you have greater OA volume in your proposed model, you may
> be penalized depending on your DCV method and diversity schedule for
> occupants in the area with DCV control.
>
> Here is an example  clarification question:
>
> *1.**       CLARIFY:*  Demand control ventilation was modeled for credit
> for RTU1 and RTU2 in the Proposed case as indicated in Table 1.4 of the
> Template; however, the outdoor air volume for RTU1 and RTU2 in the Baseline
> model was not modeled at the ASHRAE 62.1-2004 minimum rates (1,066 cfm for
> each RTU) as determined in EQp1: Minimum IAQ Performance. Appendix G allows
> schedule changes for demand control ventilation as approved by the rating
> authority (Table G3.1.4(Baseline)). As the rating authority, GBCI requires
> that the outside air ventilation rates for the Baseline Case be modeled
> using minimum ASHRAE 62.1-2004 rates wherever credit is taken for demand
> control ventilation in the Proposed Case. The Proposed case minimum rates at
> design conditions must be modeled as designed.
>
>
>
> *TECHNICAL ADVICE:*  Revise the Baseline model so the minimum outdoor air
> volume is modeled at 1,066 cfm for RTU1 and RTU2 in the Baseline model. In
> addition, provide revised SV-A reports for RTU1 and RTU2 reflecting the
> changes. Further, verify that all systems in both the Baseline and Proposed
> case are modeled with zero outside air flow when fans are cycled on to meet
> unoccupied setback temperatures unless health or safety regulations mandate
> an alternate minimum flow during unoccupied periods (in which case, the
> unoccupied outside air rates must be modeled identically in the Baseline and
> Proposed Case).
>
>
> Thomas Serra
> Project Manager
> EMO Energy Solutions, LLC
> 3141 Fairview Park Drive, Suite 450
> Falls Church, VA 22042
> voice 703-205-0445 ex-113
> fax 703-205-0449
>
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