Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
"as recommended here," ... where's here? UMH? A missing link to a specific building energy code/standard requirement, perhaps?
From the image, the spaces are clearly not hermetic (i.e. not enclosed). This will generate a number of OpenStudio & EnergyPlus errors and warnings, which in turn will create more work for you (e.g. explicitly setting space heights, volumes). The general recommendation is to ensure your spaces are enclosed, with interzone surfaces shared between adjacent spaces. This means not seeing such gaps between surfaces.
Building energy codes/standards do have different requirements when it comes to space geometry delineations. For instance, 90.1 requires that spaces shall be (in part) defined by the outside face of exterior walls. Other codes instead require the inside face of exterior walls. Yet most would require interzone walls (i.e. common to 2 adjacent spaces) to be drawn along the wall centreline (i.e. no gaps). Same with floors: should be modelled along the top of the floor slab - the adjacent ceiling below should be a mirrored copy of the floor surface (i.e. no gaps, ignoring slab thickness).
I have seen imported IFC models where gaps do exist between otherwise enclosed spaces, which generally require resorting to adiabatic boundary conditions for nearly interzone surfaces. Not ideal, but should work.
