[Equest-users] Some discuss about the Calculation Method of the software

[Karen Walkerman]

Hi Joey,

Your observations are based on the fact that the underlying simulation
engine for eQuest (DOE2) has little actual understanding of 3 dimensional
space.  I think it's easiest to start with your second example when you
move the wall out of the space.  The program itself doesn't understand that
the original space bounded by the floor, ceiling and 4 walls consisted of a
volume.  Therefore, when the wall is moved it doesn't understand that there
is a hole.  The wall is still in the program, it is still facing the same
cardinal direction, it is still assigned by the same zone, and in both
cases, it is not shaded by any other objects, so the program will model
model conduction through the wall and solar gain through the windows.  The
program does not understand the hole.

When you delete the wall, the program no longer models conduction through
the wall or solar gain through the windows.  Basically, there is no longer
a boundary there, although it's easier to think of it as an adiabatic
boundary with no mass.  This effect can be advantageous because if you need
to create custom geometry in detailed mode and need to change the polygons,
it can be difficult to get all walls to match exactly.  Having a small gap
or small hole is acceptable and doesn't lead the program to model natural
ventilation.  If you want to model natural ventilation, I believe you do
this in detail mode under the "Internal Loads" tab.

Your first example is the only one that should show a tiny amount of
difference in the result - this is because I believe that the elevation of
the building is accounted for in the calculation.  However, the internal
ceiling of the first floor is still internal and is still specified as
being adjacent to the internal floor of the second floor.

Regarding space adjacency - when you enter spaces into the wizard, it does
a decent job of figuring out which spaces are adjacent.  If it knows a
space is adjacent to another space, it will set that wall to interior.  If
the space is not adjacent, it will set the wall to exterior.  Be careful
and double check in detailed mode that everything you expect to be interior
and exterior actually came through that way.  When you make a change in
detailed mode, you need to make sure everything agrees.

--
Karen
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