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

[Carol Gardner]

Oopsie! That will teach me to read my page numbers more carefully. Bill has
kindly informed me I slipped into the prescriptive section. I say darn it!

Carol

On Wed, Jun 22, 2011 at 1:06 PM, Carol Gardner <cmg750 at gmail.com> wrote:

> 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
>



-- 
Carol Gardner PE
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