[Equest-users] Adjacent Shells

[Jeremy Poling]

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:****
>
> ** **
>
> ****
>
> ** **
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> 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****
>
> ** **
>
> [image: Senior Energy Engineer 28Jun2012] <wbishop at pathfinder-ea.com>****
>
> ** **
>
> *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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