[Equest-users] LEED Issue with EQuest Software's Ability to ModelBoilers on Ground Loops

[David Reddy]

How confident are you that the GSHX is actually large enough to meet all 
of the annual heating loads?  Depending on the building type, size, and 
climate, seems like it is reasonable for the reviewer to be skeptical.  
I've worked on a LEED-Nc v2.2  commercial building project where I 
arrived at the same conclusion, but it took a lot of extra work to 
convince myself that the GSHX model inputs, loop/equipment controls, and 
overall outputs (including hourly results) were all reasonable (LEED 
reviewer didn't seem to have an issue with it in this case).  Have you 
tried clearly illustrating/justifying the inputs for the DOE-2 GSHX 
model?  There are other programs available that you can input loads and 
GSHX performance parameters, and it will tell you what the average loop 
temperatures are over time.  I typically use these for 
comparison/validation of the DOE-2 model results.   Perhaps providing a 
secondary analysis of the GSHX would support (or potentially rebuke) 
your conclusion?

-David

On 8/15/2013 10:59 AM, Nick Caton wrote:
>
> If it were me, I'd just add the inconsequential boiler, state/show I 
> did so, and move on.  Typically less effort than building an 
> impenetrable case to someone being contrarian.
>
> To bullet #3:  I think not for the standard output reports, but loop 
> entering and exiting temperatures are options in the custom hourly 
> output report dialog, which I believe you can assign to any loop 
> type.  This will put out a CSV you can use with a spreadsheet software 
> of your choosing to quickly come up with minimums/maximums over the 
> simulation.
>
> Attached is a past thread with a spelled out / illustrated procedure 
> for setting up a custom hourly report, in case that's helpful.
>
> Best regards,
>
> ~Nick
>
> 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 
> *James Hansen
> *Sent:* Thursday, August 15, 2013 11:36 AM
> *To:* Kathryn Kerns; Steve Woolery; equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] LEED Issue with EQuest Software's 
> Ability to ModelBoilers on Ground Loops
>
> You can absolutely add a boiler to a GSHP loop.  Just add a boiler, 
> and when asked which HW loop to assign it to, you can pick the GSHP 
> Loop (as long as that loop is a "Water Loop HP" loop).
>
> I think more than likely this is the reason you are getting the 
> comments you are.  This reviewer may know that you CAN add a boiler to 
> a GSHP loop, which is the reason for comment #4.
>
> I doubt GBCI is trying to eliminate eQuest as a modeling option.
>
> Also, printing out hourly reports from an eQuest run is often helpful 
> in proving your case (whatever case that may be). If you can show, via 
> hourly reports, that the heat picked up by the GSHP heat exchanger 
> exceeds the heating load for all 8,760 hours of the day, then case 
> closed...that's all you need to submit.
>
> *GHT Limited
> **James Hansen, P.E., LEED AP*
> Senior Associate
> 1010 N. Glebe Road, Suite 200
> Arlington, VA  22201-4749
> 703-243-1200 (office)
>
> 703-338-5754 (cell)
> 703-276-1376 (fax)
>
> www.ghtltd.com <http://www.ghtltd.com/>
>
> *From:*equest-users-bounces at lists.onebuilding.org 
> <mailto:equest-users-bounces at lists.onebuilding.org> 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of 
> *Kathryn Kerns
> *Sent:* Thursday, August 15, 2013 12:27 PM
> *To:* Steve Woolery; equest-users at lists.onebuilding.org 
> <mailto:equest-users at lists.onebuilding.org>
> *Subject:* [Equest-users] LEED Issue with EQuest Software's Ability to 
> ModelBoilers on Ground Loops
>
> Everyone, I have received a snarky comment from the LEED reviewers 
> regarding eQuest and not being able to model back-up boilers on a 
> ground heat pump loop. See below. The ground loop is large enough not 
> to generate any temperature low alarm messages, the ground loop pump 
> flow never reaches 100% flow except for 1 hour and the ground loop 
> heating capacity is never exceeded. These facts do not appear to be a 
> good enough explanation not modeling the back up gas boiler.
>
> My questions for the group are:
>
> 1. Is there a way to add a boiler or some additional heat source to a 
> ground loop in eQuest?  As far as I know the only work around I have 
> discovered is to represent the ground loop by creating a water loop 
> and adding a magical no energy consuming boiler and fluid cooler to a 
> heat pump water loop and change the water loop parameters to match 
> ground loop parameters. Then you can add normal boilers that will 
> start if the non-energy consuming ground loop boiler is too small for 
> the building heat load.  I offered this option to the LEED reviewer 
> and they replied that it was not an established work around.
>
> 2. If there is no way to attach a boiler to a ground loop in eQuest, 
> is there some established work around that somebody has used that was 
> accepted by a LEED reviewer?
>
> 3. Is there anything in the reports that lists the maximum and minimum 
> ground loop temperatures? I have been unable to locate it.
>
> 4. Does anyone have an written explanation to answer "/If this /[the 
> boiler] /is not being modeled in the energy modeling software then 
> provide a thorough explanation for why it cannot be modeled. "?/
>
> /5./ Does this sound like LEED is trying to eliminate eQuest software, 
> and if so, is there anything we can do about it? "/in the future the 
> software selected to simulate the building components must be able to 
> model those components "/
>
> /The project team could possibly demonstrate that the boiler would not 
> operate through a series of engineering calculations, some other 
> software that could possibly simulate the building's loop 
> temperatures, or through a thorough explanation of how the system 
> operation prevents the boiler from operating. In short the project 
> team must demonstrate that the boiler will not operate, not just say 
> that is the case without presenting some evidence. If this is not 
> being modeled in the energy modeling software then provide a thorough 
> explanation for why it cannot be modeled. In the future the software 
> selected to simulate the building components must be able to model 
> those components or use an exceptional calculation (work around) to do 
> so (G2.2). /
>
> ------------------------------------------------------------------------
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