[Equest-users] eQuest Accounting for Exhaust Fan Energy for LEED

[Carol Gardner]

What about if the exhaust fans use 1 hp or less? Does everyone follow the
directions in 6.5.3.1.1?

Beelzebub

On Wed, Jun 22, 2011 at 10:59 AM, Demba Ndiaye <Demba.Ndiaye at setty.com>wrote:

> I second Nick’s approach: put the exhaust flows where you think the air
> will come from. ****
>
> ** **
>
> In my experience, that is the best way to handle air transfer through
> exhaust in eQuest.****
>
> ** **
>
> And I believe that the wizard is also doing it for you if you specify zonal
> exhaust before leaving it …****
>
> ** **
>
> ______________****
>
> Demba NDIAYE****
>
> ** **
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Nick Caton
> *Sent:* Wednesday, June 22, 2011 1:07 PM
> *To:* Bishop, Bill; Anthony Hardman; Seun Odukomaiya;
> equest-users at lists.onebuilding.org
>
> *Subject:* Re: [Equest-users] eQuest Accounting for Exhaust Fan Energy for
> LEED****
>
> ** **
>
> I’ve run into this at least once, and an approach that has worked for me is
> a riff on Bill’s first suggestion.  Start with: where is the air coming
> from?****
>
> ** **
>
> If the negative space is a bathroom that in reality is drawing air from an
> adjacent open office space under the same system, why not specify the
> exhaust (wholly or in part) in the open office space?  Perhaps another large
> minimum-airflow space under the same system would work as well?  Airflows
> and cooling requirements should balance out at the system level provided the
> exhaust does not exceed the local zone airflow rate.****
>
> ** **
>
> The balance of airflows may not work for every case, but this can
> potentially be the simplest approach.  Consider carefully whether the
> quantity and scheduling of the exhaust will cause it to exceed the hourly
> supply air rate for the zone(s) you’re considering.****
>
> ** **
>
> `Nick****
>
> ** **
>
> [image: cid:489575314 at 22072009-0ABB]**
>
> * *
>
> *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* *****
>
> ** **
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Bishop, Bill
> *Sent:* Wednesday, June 22, 2011 10:43 AM
> *To:* Anthony Hardman; Seun Odukomaiya; equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] eQuest Accounting for Exhaust Fan Energy for
> LEED****
>
> ** **
>
> Seun,****
>
> ** **
>
> I’ve used a few different approaches to address the situation of a zonal
> exhaust fan that has a flow rate close to, or larger than, the supply air
> flow to that zone:****
>
>                 - Model the zone as being part of the zone that it draws
> transfer air from. (An example would be a single zone representing a
> corridor and a janitor closet.)****
>
>                 - Increase the supply air flow to the zone with the exhaust
> fan, and decrease it by the same amount in the zone that it draws transfer
> air from.****
>
>                 - Create a different thermostat schedule(s) to allow the
> temperature to float more, and use the same schedule in both Baseline and
> Proposed. (If appropriate, for example, use a 60°F heating setpoint.)****
>
>                 - Make the zone with exhaust fan an unconditioned zone.
> This might be appropriate for a trash/recycling or soiled linen room where
> you are not trying to condition it within a certain temperature range.****
>
> ** **
>
> Regards,****
>
> Bill****
>
> ** **
>
> [image: Signature in jpg form]****
>
> ** **
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Anthony Hardman
> *Sent:* Wednesday, June 22, 2011 10:45 AM
> *To:* 'Seun Odukomaiya'; equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] eQuest Accounting for Exhaust Fan Energy for
> LEED****
>
> ** **
>
> I’ve run into the same problem too.  One thing I’ve tried is to decrease
> the zone level EA cfm until the unmet hours are reasonable, and then
> increase the kw/cfm the commensurate amount.  That way, at least there’s
> some zone level exhaust airflow and the SV-A report shows EA fan power equal
> to what is on the exhaust fan schedule.  A narrative to the GBCI reviewer
> explaining the simulation limitations would hopefully suffice.  ****
>
> ** **
>
> *Anthony Hardman, PE*
>
> *LEED AP BD&C*
>
> Building Performance Analyst****
>
> ** **
>
> *THE GREEN ENGINEER, LLP*
>
> *Sustainable Design Consulting – Energy Modeling – LEED Project Management
> *****
>
> 50 Beharrell St****
>
> Concord, MA 01742****
>
> O: 978/610-2801****
>
> C: 720/840-7862****
>
> ** **
>
> [image: Description: TGE Logo] <http://www.greenengineer.com/>[image:
> Description: images5] <http://www.linkedin.com/in/ahardman81>[image:
> Description: t4] <http://twitter.com/#%21/a_Hardman>****
>
> ** **
>
> ** **
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Seun Odukomaiya
> *Sent:* Wednesday, June 22, 2011 8:15 AM
> *To:* equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] eQuest Accounting for Exhaust Fan Energy for
> LEED****
>
> ** **
>
> eQuesters****
>
> ** **
>
> I'm having some difficulty with properly modeling exhaust fans in for LEED
> and I'm hoping someone can provide me with some guidance. ****
>
> ** **
>
> Here's my problem: I can enter the exhaust volumes and associated KW/cfm
> for each zone where necessary, but some of the spaces have design exhaust
> volumes greater than design supply air volumes (negative pressure rooms). If
> I select "infiltration" or "balanced infiltration" as the source of exhaust
> makeup for these zones, then the unmet hours for that zone become very high.
> If I select "air handler" as the source of makeup air, then eQuest increases
> the design supply air volume to match the exhaust air volume for that zone.
> This is problematic because the SV-A reports now have values that do not
> match my mechanical schedules. Additionally, the energy consumption
> associated with those systems increases as a result of the increased supply
> air volume. All in all, it's just not an accurate representation of the
> design. Most of these zones are expected to make up the air through zonal
> air transfer (something I realize eQuest is unable to do).****
>
> ** **
>
> At this point, I'm considering adding the exhaust energy as a direct load
> to my meter along with appropriate usage schedules, and associating it to
> "ventilation fans". I believe the net effect on energy consumption and peak
> demand should be the same as if the exhaust fans were explicitly modeled.
> However, I'm curious as to any dynamic system or thermal effects that I may
> be circumventing by not explicitly modeling the exhaust fans for each zone.
> My gut feeling is that there shouldn't be much of an effect, but I'm just
> not sure. I'm also concerned that by modeling exhaust energy as a direct
> load, rather than explicitly, the SV-A reports won't show any exhaust
> volumes and thereby call attention as to the validity of the model.****
>
> ** **
>
> At this point, I would like the guidance of some of the members on this
> forum that have more experience with these issues. Is this even an
> acceptable way to account for exhaust fan energy for LEED? I'm open to any
> suggestions from anyone who has run into these issues and/or may have
> experience in how to deal with it.****
>
> ** **
>
> Thanks in advance****
>
> ** **
>
> *Seun Odukomaiya, EIT, LEED AP* |* Mechanical Engineer* | *L’Acquis
> Consulting Engineers** *|(317) 706-2075 Ext. 255 | www.lacquis.com<http://www.laceindy.com/>| To
> transmit large files, please use:  http://lacquis.leapfile.net****
>
> ** **
>
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-- 
Carol Gardner PE
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