[Equest-users] Modelling Parking Garage Exhaust CombinedwithJetFans

[Robby Oylear]

Yes, but the baseline code for a LEED analysis is ASHRAE 90.1, which does
not require CO modulation of parking garage ventilation.

How can they justify rewarding the exact same strategy for one project and
not for another, based on the local codes?

For example, the Seattle Energy Code has more stringent lighting power
density requirements than ASHRAE 90.1.  In LEED CS projects we've been able
to take credit for lower LPD's despite not knowing the final tenant build
out, due to the code requirements. By the logic proposed by this comment,
this would not be an allowable savings strategy.

*Robby Oylear, LEED**®** AP BD+C*

*Mechanical Project Engineer*

*Energy Analyst*

* *

*D* 206-788-4571 | *C* 206-354-2721

*www.rushingco.com* <http://www.rushingco.com/>


On Tue, Aug 2, 2011 at 8:44 AM, Amber Welsh <amber at timmonsdesigneng.com>wrote:

> I think they are asking for you to reference if this is required by local
> code.  For instance, the city of San Francisco will require CO sensing for
> parking garage exhaust.  In which case the methodology is explained.  If it
> is not required by code, then I would ask GBCI if you include the selection
> of code relevant to parking garage ventilation to back-up your baseline
> model.
>
> Baseline is always based on baseline code, not anyone's personal base
> design strategies.  This is the whole point and benefit of having a
> standard.
>
> Amber
>
> -----Original Message-----
> From: equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
> Sent: Tuesday, August 02, 2011 11:28 AM
> To: James Hansen; Ömer Moltay; equest-users at lists.onebuilding.org
> Subject: Re: [Equest-users] Modelling Parking Garage Exhaust
> CombinedwithJetFans
>
> Great heads up - I haven't run into that one yet!
>
> While I don't disagree with what the reviewer is getting at (standard
> practices do evolve), I think he/she is crossing a line by putting the
> burden of proof for a baseline practice on the modeler...
>
> What's potentially unfair about this situation is that it artificially
> punishes those who try to design above and beyond the prescriptive minimums.
>  Measures like CO sensing controls are ultimately
> either done because (A) you have to, or (B) because you want to do more
> than is required.  If LEED reviewers today are taking it upon themselves to
> NOT reward those going above and beyond code requirements, then to be
> even-handed I'd expect in turn they're making a point to punish those who do
> the bare minimum.
>
> If the new mandate is that baseline garage ventilation should always
> include CO sensing, then come out and say it (and define how it's to be
> modeled exactly while you're at it).  Write it into 90.1 or the next version
> of EAc1.  Don't arbitrarily punish owners and designers who are trying to do
> more than the minimum.
>
> ~Nick
>
> NICK CATON, P.E.
> SENIOR ENGINEER
>
> Smith & Boucher Engineers
> 25501 west valley parkway, suite 200
> olathe, ks 66061
> direct 913.344.0036
> fax 913.345.0617
> www.smithboucher.com
>
>
> -----Original Message-----
> From: James Hansen [mailto:JHANSEN at ghtltd.com]
> Sent: Tuesday, August 02, 2011 10:08 AM
> To: Nick Caton; Ömer Moltay; equest-users at lists.onebuilding.org
> Subject: RE: [Equest-users] Modelling Parking Garage Exhaust Combined
> withJetFans
>
> Please also note that if this is for a LEED project, one of the "default"
> review comments now for CO-based control of garage fans is that the design
> professional must demonstrate that this is not a "standard practice" for new
> base-building projects in the area.  I personally think this is a ridiculous
> comment, but regardless, be prepared to provide a list of new projects in
> the area that you've worked on that have not had CO-based control of the
> parking garage fans, otherwise you might have to include it in both the
> baseline and proposed models.  I would love to hear how other people have
> addressed this comment.
>
> GHT Limited
> James Hansen, P.E., LEED AP
> Senior Associate
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> -----Original Message-----
> From: equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] On Behalf Of Nick Caton
> Sent: Tuesday, August 02, 2011 11:01 AM
> To: Ömer Moltay; equest-users at lists.onebuilding.org
> Subject: Re: [Equest-users] Modelling Parking Garage Exhaust Combined
> withJetFans
>
> Hi Ömer,
>
> A1: If you're not conditioning the fresh air, then there's no reason to try
> and model this ventilation as a SYSTEM.  Assign a direct load to your meter.
>  Assign to a submeter if you wish to separately track its energies easily.
>  Further discussion in the archives if you need to ask how.
>
> A2: A fractional schedule is necessary to model CO sensor-based controls.
>  If you're doing this under LEED:  90.1-2007 users manual, which offers
> specific schedules for specific occupancies (adapted from 90.1-1989, also
> used in the Washington State energy code IIRC)... has a table for parking
> garages.  Rather than provide an hourly fraction as with most other cases,
> it says Parking garage HVAC shall be "Based on likely use."  I interpret
> this as a prescriptive latitude to define and assign schedules appropriate
> to your system's behavior on a case-by-case basis.
>
> A3: "Model the airflows" is a fairly vague query... Are these operating for
> user comfort?  If they're tied to a thermostat, it might be easiest to set
> them up as a system with a thermostat.  If they're just
> circulating/directing ventilation air alongside the main exhaust fan, then
> I'd treat them identically as a direct load to the meter, per A1.  I'd use
> an identical or modified schedule from that used for the exhaust fan,
> depending on whether they operate identically.
>
> ~Nick
>
> NICK CATON, P.E.
> SENIOR ENGINEER
>
> Smith & Boucher Engineers
> 25501 west valley parkway, suite 200
> olathe, ks 66061
> direct 913.344.0036
> fax 913.345.0617
> www.smithboucher.com
>
>
> -----Original Message-----
> From: equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] On Behalf Of Ömer Moltay
> Sent: Tuesday, August 02, 2011 6:05 AM
> To: equest-users at lists.onebuilding.org
> Subject: [Equest-users] Modelling Parking Garage Exhaust Combined with
> JetFans
>
> Dear All,
>
> In a building with 6 underground parking storeys, air is exhausted
> through a shaft and a single fan, while outside air is brought in
> through natural flows on another shaft. This is achieved by jet fans
> operating in each parking garage. The exhaust fan is variable speed
> controlled by CO sensors in the parking areas.
>
> Q1: How can I assign 6 underground zones to a single exhaust fan? As far
> as I know, exhaust flows are assigned on a zone basis in eQuest?
> Q2: How to model the speed variation of the exhaust fan? Any other way
> other than using schedules?
> Q3: Can eQuest model the airflows caused by jet fans? Or should I just
> assign these as electric loads so that their electric consumption is
> taken into account?
>
> Thank you,
>
> Ömer Moltay, LEED AP BD+C, BREEAM Assessor
> Mimta Ltd.
> Hekimsuyu Cad. 559. Sk. No:39
> 34255 Kucukkoy Istanbul Turkey
> Tel: 90-212-617-2296
> Fax: 90-212-617-2297
> www.mimtarch.com
> www.mimtasolar.com
> www.eko-yapi.net
> www.servogas.com
>
> Sürdürülebilir Binalar Blog
> http://surdurulebilirbina.blogspot.com
>
> Green Building in Turkey on LinkedIn
> http://www.linkedin.com/groups?gid=2278249
>
>
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