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

[Karen Walkerman]

You are missing the fact that the rules are being changed at the REVIEW
stage.  This requires the energy modeler to do a-lot of extra work to change
the baseline model during the review stage.  It also means that after
changing the model, if the reviewer has any additional comments or
questions, the energy modeler will have to go through an additional review,
and pay an additional fee to have the USGBC look at their documentation
again.

Also, the fact that this rule seems to be implemented for some projects, and
not for others means that buildings are not being rated fairly against each
other.

The debate about whether this makes sense or not should be kept separate
from this discussion.  My main concern is that rules are being changed
without letting the players know.  Any time they make changes, it needs to
be documented publicly, preferably with changes only applying to projects
registered after the date of publication.

We can debate separately whether this rule change makes sense.  Yes, I
understand that some "gaming" of the system could happen, in theorgy, but in
many cases, adding HUGE amounts of outdoor ventilation air as you suggest is
far too costly to implement.

Thanks,

--
Karen Walkerman

On Tue, Jul 27, 2010 at 9:13 AM, James Hansen <JHANSEN at ghtltd.com> wrote:

>  I’m not sure I really understand what the fuss is about.  If you’re
> designing and modeling a building that does NOT have DCV, then it seems
> entirely fair (and accurate) to model the same ventilation rates in both the
> baseline and the proposed.  If, however, you are implementing a DCV
> strategy, then regardless of what you set your “maximum” OA rate at for the
> proposed model, in reality, the DCV system is going to keep OA flow rates
> near or below the ASHRAE 62.1 requirements (in real life operation).
>
>
>
> If the TAG committee didn’t require you to model the baseline building at
> ASHRAE 62.1 flow rates when DCV is being implemented, then theoretically you
> could input an astronomically high OA flow rate for both models, knowing
> that your proposed model would NEVER run at such a condition and would have
> an unfair advantage.
>
>
>
> This seems like an entirely acceptable and fair ruling.  What am I missing?
>
>
>
> *GHT Limited
> **James Hansen**, PE, LEED AP*
>
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> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Karen Walkerman
> *Sent:* Tuesday, July 27, 2010 9:05 AM
> *To:* equest-users at lists.onebuilding.org
>
> *Subject:* Re: [Equest-users] GBCI comments on DCV (Carol Gardner)
>
>
>
> 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
>
>
>
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>
>
>
> *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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