Zoning Issue

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I am modeling an addition to an existing building. The new addition has
three perimeter exposures and the fourth exposure is up against the existing
building, which is a conditioned space.

How do I tell equest that one of my exposures is not a perimeter wall but
it is basically a partition with a conditioned space adjacent to it?

Thanks

Richard J. Dominick, P.E.

RJTHEACMAN at aol.com's picture
Joined: 2011-09-30
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You will have to define the common wall as an "adiabatic" interior
partition -- no heat transfer and no solar load. In the wizard you can
do this by clicking on the wall (in Shell screen 2 of the DD wizard) and
then selecting adiabatic. In detailed mode you can also delete a
exterior wall and then create an interior partition of type adiabatic.
You could also simply delete the common wall -- this also has no solar
and no conduction load. The only thing this does is decreases the
room's thermal mass slightly (not of significance likely).

There is no way to create and interior partition and to force the
temperature of the adjacent space -- you would have to create the "next
to" zone if you really want to model heat transfer between new and
existing. Unless the occupancies are significantly different, the
impact of conduction across that wall is likely negligible.

Good luck.

BF

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In full support of Brian's response, I'd add one extra tidbit:

Post-wizards, I would generally take the "delete the wall" approach 9
times out of 10 without a second thought. In the event you do feel the
mass of the common wall has a significant thermal lag effect you don't
want to eliminate in your model, I'd advise still just deleting the wall
and bumping up the value for the furniture mass (located under the
contents tab for the space in question).

Creating an interior wall to match a wizard-generated exterior (which
I've written a mini guide on, btw - see archives) is something I'd
generally only advocate if model aesthetics are critical (the 3D view).
Deleting the wall surface entirely is a quick solution, but has the side
effect of giving you superman-like xray vision powers when in the 3D
view... this has raised eyebrows in my experience and I have had to
explain the modeled behavior is not what it looks like.

Personally, I reserve and maintain the right to make ugly models
whenever it saves me time and doesn't hinder accuracy, but to each
his/her own ;).

NICK CATON, E.I.T.

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Someone asked me a pointed question and I'd had to misguide anyone.
Added an extra line to my response below to clarify my position.

I also remembered that you won't be able to actually view that
particular "mini-guide" in the archives I referenced as it was all
pictorial - sorry! I've re-attached the guide pictures and copied the
discussion that prompted it below for your reference.

NICK CATON, E.I.T.

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The archives now include links to attachments using the
original names of the attachments.

Nick's email is at:

http://tinyurl.com/2g964sc

If you scroll all the way to the bottom, you can click on
the links and see all the various graphics that were attached.

I requested this change in the way archives work from the
web host that hosts onebuilding.org.

Jason

Jason Glazer's picture
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Thanks for all your help.

In a message dated 11/10/2010 1:32:16 P.M. Eastern Standard Time,
ncaton at smithboucher.com writes:

Someone asked me a pointed question and I?d had to misguide anyone. Added
an extra line to my response below to clarify my position.

I also remembered that you won?t be able to actually view that particular
?mini-guide? in the archives I referenced as it was all pictorial ?
sorry! I?ve re-attached the guide pictures and copied the discussion that
prompted it below for your reference.

NICK CATON, E.I.T.

RJTHEACMAN at aol.com's picture
Joined: 2011-09-30
Reputation: 0