Re: [EnergyPlus_Support] Re: Modelling full height windows

["David Scheer - L+U" <david@xxxxxxxxxxxxxx>]

You should use the Sketchup plugin to look at what is actually being created by DesignBuilder (and to modify the geometry if you are going to work in IDF and not go back to DB).  In my experience, DB exports geometry with wall thicknesses only for the boundaries of Blocks (in the proprietary DB lingo), which turns out to create wall thicknesses in only some conditions:
- exterior walls - I think this is how blocks are generally meant to be used.  DB actually exports the interior surface of exterior walls to IDF.  This means that at Block corners (but not necessarily zone corners) there is a virtual thickness.  As you can imagine, this emphasis on interior volume over exterior surface area has to be considered in many cases.
- interior walls are NOT given a thickness when they are created by subdividing blocks, though there ends up being a return that you can't access in DB.  Interior walls are modeled as a plane at the center of the wall you see in DB interface.
- interior walls created by joining two blocks into one with an 'airwall' will have a thickness, but also a bunch of sidewalls and return surfaces within the opening.  Creating zones with blocks is necessary when there is geometry that can't be handled natively by the software.  This is also necessary for plenums or any horizontal zone boundaries, as you can only subdivide in plan in DB.

So in general, you should be able to get your windows nearly edge to edge between zones if you are dividing a block.  DB may not let you do it directly, as the wall thicknesses show up in the DB interface, and the tool creates returns at some wall intersections.  But if you look at the geometry with the SU plugin, you'll see that there are no wall thicknesses in interior walls.

r3 

  ----- Original Message ----- 
  From: careym.cosmaj 
  To: EnergyPlus_Support@xxxxxxxxxxxxxxx 
  Sent: Saturday, May 10, 2008 1:35 PM
  Subject: [EnergyPlus_Support] Re: Modelling full height windows


  --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "David Scheer - L+U"
  <david@...> wrote:
  >
  > What front-end are you using that models wall thickness?

  As I understand it, from inspection, DesignBuilder allows the user to
  set the thickness of a block or partition wall as it is being created.

  The thickness is not used in U value calculations, it is just used
  within the frontend during modelling and prevents windows, openings,
  vents etc being located at the extreme edges of Surfaces.

  Which in effect prevents the user from being able to create a window
  that covers a whole surface.

  Regards,

  Mark Carey



   

[Non-text portions of this message have been removed]


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