Greetings All,
I am attempting to model a two-story multi-family structure with 16
apartment units, 8 per floor. The building is symmetrical with 8 units in
the middle section (4 units per floor) and 4 units (2 units per floor) on
either side. Despite being one structure, the plans indicate that it is
actually divided into 3 separate Thermal Shells because there is a stairwell
and an unconditioned boiler room in between each of the three "volumes".
Thus far, I have only been able to model buildings in eQUEST as one box or
volume. I would like to be able to model this structure accurately (as three
separate thermal shells under one roof). Does anyone know how to do this?
Also, I continue to have problems generating the roofs accurately. I will
draw a box-like building footprint and when the roof generates in equest, It
is often times pitched in the wrong direction or does not have the correct
relationships between roof elements. Can anyone help me use the custom roof
footprint option? I have "fudged" some eQUEST models in the past where I
thought it would not effect the accuracy of the model much, however, I am
hesitant to fudge this model as such being that there are four long walls in
this building that will losing considerable heat to the exterior stairwells
and unconditoned boiler rooms (in between the volumes). Any suggestions
would be greatly appreciated. Thanks.
Regards,
Vaughn Slovak
Hi Vaughn,
1. You can define 3 separate shells easily in the DD wizards.
Start by finding/making a Cad file containing each shell footprint in
geometric relation to each other, finish out your first shell
(geometries, scheduling, constructions, LPD, etc) as you normally would,
then start another by copying the first and reference the same file when
tracing out new shells. This will have the advantage of creating
additional exterior walls where you need them (stairwell), but you
should probably include the boiler rooms in the shell they're attached
to as unconditioned spaces, to get those losses correctly modeled.
2. You may want to define the exterior stairwells as a series of
building shades (just the landings would be fine) in detailed mode after
the wizards. This will mitigate solar loads such exterior walls would
not actually see. This may also cover the "gaps" between the shells if
you are concerned aesthetically about "one roof."
3. The advice I generally follow regarding custom/tilted roofs is
that it's usually not worth the effort - flat roofs can often
approximate thermal interactions to a plenum space quite well enough.
That said, if your heart is set on custom tilted roof shapes - you're
going to need to resolve to spend some time after the wizards crunching
numbers in detailed edit mode to modify the vectors of the
wizard-generated polygons. I'd recommend searching the archives for
more procedural info or starting a separate query if you get hung up in
this.
4. Your concern that the roof shape will affect the (exterior?)
stairwells' behavior gives me pause however... not sure what you mean
there. Defining 3 separate, non-touching shells will account for the
additional exterior walls you'd want to model if that's what you mean...
Someone wise once told me that "accuracy" is not nearly as important as
understanding "accurate enough."
NICK CATON, E.I.T.