window addition to adiabatic wall

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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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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

[cid:489575314 at 22072009-0ABB]

NICK CATON, P.E.

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Vamshi,

I have not looked closely at the application of a 'sunspace' in eQuest. However, I believe a sunspace allows you to model interior windows on one wall of an interior zone to model light/heat transfer into the space via the window/wall construction. A thorough investigation on this forum and a review of specific hourly reports could yield the answer you are looking for.

Thanks,

David Griffin

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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.

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