[Equest-users] window addition to adiabatic wall

[Nick Caton]

Per my first suggestion - you do not want to model exterior perimeter walls as interior surfaces, adiabatic or otherwise.  Interior surfaces of any sort will  not interact with exterior conditions & produce envelope loads.

I recommend first searching for 'courtyard' and/or 'cutting method' in the mailing list archives for a few discussions & pictures on how to use the wizards to create exterior walls & windows for courtyards.  Leveraging the wizards is by far the easiest approach.

If you are in detailed mode and don't want to return, or are otherwise uncomfortable with some of the approximations the cutting approach can lead to, you can also directly replace the courtyard "partitions" with exterior walls of appropriate construction & identical geometry, then define windows in those walls as you've already done.  Here's a pictorial guide showing the reverse action (changing exterior surface --> interior surface) - this should prove helpful if you are new to such edits.  Same procedure:  http://onebuilding.org/wiki/doku.php/convert_an_exterior_surface_to_an_interior_surface_detailed

~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: vamshi ranga [mailto:vamshiranga at gmail.com]
Sent: Tuesday, October 16, 2012 6:03 AM
To: Nick Caton
Subject: Re: [Equest-users] window addition to adiabatic wall

Hi Nick,

Thank you very much for detailed replay..

Actually, by mistake courtyard is modeled as interior opening  (however, it should be modeled as exposed to atmosphere and walls should be exterior walls), so, equest considered them as adiabatic walls by default, but as per the drawings we have glazing on these walls, even we model glazing to adiabatic walls, the energy consumption is not getting changed, so the issue is, how to model both U value and SHGC implications in the model?

Thanks
Vamshi

On Mon, Oct 15, 2012 at 8:34 PM, Nick Caton <ncaton at smithboucher.com<mailto:ncaton at smithboucher.com>> wrote:
Vamshi,

Adiabatic walls are interior surfaces which will not permit heat transfer, by definition.

If you intend to add a window to an exterior wall, you should not be using an interior surface.

If you intend to model a window in an interior partition, using an adiabatic surface may well hinder your efforts - better to switch an option which models heat transfer.

If your goal is to model the solar gains to a core space through a perimeter sunspace via interior windows, you should review the attached discussion from bldg-sim.  I understand this is possible with some care - but it requires careful review of the associated help resources to get all your ducks in a row.  One "gotcha" is that you are required to use the "by glass code" definition approach for the associated exterior windows.

If your goal is to simply model the conductive heat transfer (not solar transfers) of those windows, you may consider defining an interior surface by construction type (not adiabatic), and weight the U-values and areas of the windows & partition construction together for a net U-value -I did this extensively in the past, before realizing windows can be defined for interior surfaces.

Food for thought: I would not anticipate a correct model to exhibit a great change in energy consumptions if the two interior spaces in question are both conditioned to similar/same setpoints.  If the difference in temperatures are not great, changes in the partition conductive properties will not have a great effect as heat will not be inclined to move much to begin with.

~Nick


NICK CATON, P.E.
SENIOR ENGINEER

Smith & Boucher Engineers
25501 west valley parkway, suite 200
olathe, ks 66061
direct 913.344.0036<tel:913.344.0036>
fax 913.345.0617<tel:913.345.0617>
www.smithboucher.com<http://www.smithboucher.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<mailto:equest-users-bounces at lists.onebuilding.org>] On Behalf Of vamshi ranga
Sent: Monday, October 15, 2012 9:10 AM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: [Equest-users] window addition to adiabatic wall

Hi,

eQUEST has created "Adiabatic Interior Wall" by default, if I add a windows to those areas, still there is no change in energy consumption. My doubts is,

 - Is it not possible to change adiabatic wall properties even if we add window?

Thanks
Vamshi.

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