[Equest-users] Adjacent Shells

[Paul Diglio]

Jeremy:

I had a small project, just 12,000 Ft2.  I needed to model a small shell that 
was underground and fitted into the other building.   It is that small area with 
the 6 skylights on the west axis.  See attached jpg.

Initially I modeled the main building with exterior walls where this section 
fits in and modeled the section with interior walls.  I then deleted the 
exterior walls on the main building and left the interior walls on the section.

By deleting the exterior walls I reduced the unmet hours from 42 to 39.  Energy 
consumption reduced from $27,905 to $27,886 (.02%)

 Paul Diglio, CEM, CBCP


87 Fairmont Avenue
New Haven, CT  06513
203-415-0082


www.pdigliollc.com




________________________________
From: Jeremy Poling <jeremy.poling at att.net>
To: "Sami, Vikram" <Vikram.Sami at perkinswill.com>
Cc: "equest-users at lists.onebuilding.org" <equest-users at lists.onebuilding.org>
Sent: Wed, January 23, 2013 6:20:52 PM
Subject: Re: [Equest-users] Adjacent Shells


Thanks Bill and Vikram - with most buildings this would be an easy solution, but 
with this particular building the problem involves hundreds of these exterior 
surfaces.  Unfortunately, the changes in building geometry are not minor enough 
to simplify - bump outs exceeding 20 feet, changes in direction and angle of the 
building, etc.  I should have noted that the 4M+ SF is spread across 4 floors...
 
I'll take a look at it once the architecture is finally complete in the model.  
I'll have to do it as best as possible in the 3D view since without a pan 
feature I can't get close enough to the tails of the building to visualize the 
sections that are exterior.
 
If anyone does have an idea on what percentage of the load these phantom skin 
loads can add up to in more typical cases, that would be helpful: following 
ASHRAE 14 there's room for some small percentage error adjustments due to things 
like this.  To put it a little differently, we're recommending the owner finish 
changing the last few incandescents to alternate sources (depending on 
application, LED or CFL) but the threshold for showing up as a percentage of 
energy use in the building is so high all of the incandescent sources remaining 
wouldn't show up on the simplified results in eQuest. :)  Fun "little" project, 
yes?

Jeremy R. Poling, PE, LEED AP+BDC
 
 


On Wed, Jan 23, 2013 at 3:48 PM, Sami, Vikram <Vikram.Sami at perkinswill.com> 
wrote:

I agree with Bill – don’t leave them as exterior walls – you will get non 
existent skin loads in those zones. 

> 
>Another thing worth trying (if you are going through the wizard) is to make the 
>building footprint slightly bigger than the zone footprint on that side of the 
>building.  Like this:
> 
> 
>You will end up with interior walls in those zones like so:
> 
> 
>Hope this helps
> 
> 
>Vikram Sami, LEED AP BD+C
>Sustainable Design Analyst
>1315 Peachtree St. NE, Atlanta, GA 30309
>t: 404-443-7462    f: 404.892.5823       e: vikram.sami at perkinswill.com   
>www.perkinswill.com
>Perkins+Will.  Ideas + buildings that honor the broader goals of society
> 
> 
>From:equest-users-bounces at lists.onebuilding.org 
>[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Bishop, Bill
>Sent: Wednesday, January 23, 2013 2:59 PM
>To: Jeremy Poling; equest-users at lists.onebuilding.org
>Subject: Re: [Equest-users] Adjacent Shells
> 
>Jeremy,
> 
>Well, every one of those extraneous exterior walls (and roofs) is going to be 
>simulated as envelope loads on those spaces. The model doesn’t know that they 
>aren’t actually exposed to the outdoors. I would certainly delete them for any 
>model, calibrated or otherwise, if it were me. You could determine the impact, 
>relatively quickly, by modifying the U-factor of your wall construction based on 
>the ratio of modeled exterior wall area to actual exterior wall area. Get your 
>modeled wall area from the last page of the LV-D report, and divide by the 
>actual wall area of the existing building. Divide the wall construction U-factor 
>by the modeled-to-actual wall ratio, and modify the wall construction 
>accordingly. Simulate and see how much the energy is reduced. Okay, never mind 
>that sounds like too much work. Just delete the walls.
> 
>If you’re in that much of a hurry, don’t replace the exterior walls with 
>interior walls. Just delete the exterior surfaces and be done with it. I usually 
>add the interior walls, especially if the adjacent spaces have different 
>thermostat setpoints or different internal loads. These edits can be pretty 
>quick when you modify the 3-D view to more easily see where the extra surfaces 
>are:
> 
> 
>Regards,
>Bill
> 
> 
>From:equest-users-bounces at lists.onebuilding.org 
>[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Jeremy Poling
>Sent: Wednesday, January 23, 2013 2:33 PM
>To: equest-users at lists.onebuilding.org
>Subject: [Equest-users] Adjacent Shells
> 
>Two questions in the same day...I may have more still :)
> 
>Has anyone taken the time (maybe Nick?) to determine if there is a major impact 
>due to leaving walls of adjoining shells as exterior instead of changing them to 
>interior, air-walls, or deleting them?  I only ask because I have a 4M+ SF 
>building that is requiring 20+ shells stacked and adjacent and I'm looking for 
>every time saver I can find.  I simplified the shells as much as possible, but 
>due to geometry this is the smallest number I can squeak by with from an 
>orientation/geometry/overlap.
> 
>I should note, this is an existing building and the model is being more or less 
>calibrated, so just having a rough idea of the impact of this nuance will allow 
>me to decide to take the time or to chalk it up in my model error.
> 
>Thanks much!
>
>Jeremy R. Poling, PE, LEED AP+BDC
> 
> 
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