[Bldg-sim] Really need some deep DOE-2 theology on this one..

[Fred Betz]

Agreed, make the change in the .inp file for the appropriate shells.

It helps to give the incorrect roofs a different construction so you can search them more easily. Also, save a copy of the .inp file before making your edits. I’ve found it’s too easy to make a mistake in the .inp file that corrupts the whole model.

It is unfortunately a very common mistake in the wizard that is a pain to fix in the detailed mode, but that’s the best way I know how to correct the problem.


Fred Betz  PhD., LEED AP ®BD&C
Sustainable Systems Analyst



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From: David Eldridge [mailto:dancingdavide at hotmail.com]
Sent: Sunday, September 29, 2013 10:46 AM
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] Really need some deep DOE-2 theology on this one..

If you did opt for conversion, it is probably easier to do so in the INP file than detailed interface.

Adding a bunch of ceilings will also require matching floors for "adjacent-to" surfaces - just deleting sounds easier.

DSE Mobile

On Sep 29, 2013, at 10:01 AM, "Maria Karpman" <maria.karpman at karpmanconsulting.net<mailto:maria.karpman at karpmanconsulting.net>> wrote:
John,

Having extra exterior roof area is a fairly common mistake in eQUEST models involving multiple shells. It typically originates on DD Wizard Screen 3, when roof construction is specified in the Construction list box for a shell that has no roof (i.e. shell that includes only the middle floors of the building), instead of setting it to “-no exterior exposure (adiabatic)”.  Any exterior surface in eQUEST will conduct heat between the parent space and the ambient, even if it is adjacent to another conditioned space based on 3D view, so having extra roof area does affect simulation results. The easiest way to fix the problem is to delete the extra exterior roof surfaces. Converting them to interior walls as Patrick suggested is a more precise approach, but is also more time consuming and will have negligible impact on results for most projects, especially if the result of interest is Appendix G performance rating.

Thanks,

Maria

From: bldg-sim-bounces at lists.onebuilding.org<mailto:bldg-sim-bounces at lists.onebuilding.org> [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Patrick J. O'Leary, Jr.
Sent: Saturday, September 28, 2013 9:41 PM
To: John Aulbach
Cc: bldg-sim at lists.onebuilding.org<mailto:bldg-sim at lists.onebuilding.org>
Subject: Re: [Bldg-sim] Really need some deep DOE-2 theology on this one..

this sounds like you have multiple shells in one model for this to occur?  i'm pretty sure equest views an exterior wall/roof as an exterior wall/roof even if it is bounded by an interior wall.  i had this problem come up on one of my own models where i ended up having a building wing meet the building trunk & as i had put them in as 2 separate shells equest did not recognize the dividing wall where the wing met the trunk as being an interior wall & assigned it (via the wizard) an exterior wall definition.  i didn't catch this until reviewing the unmet load hour ss-r & s-va reports & couldn't figure out why the load was so high.  changed the definition of the wall to interior (with a door) in detailed mode and the unmet load hours went to zero and the load came down.

my understanding (in my case) is that if you create multiple shells and place them with a common wall that you want to be an interior the shell rotations need to be zero, even if you have the separation between the two shells occur at a 45 deg angle (then ask mr. architect about that one).

On 9/28/13 4:47 PM, John Aulbach wrote:
Hi Gang:

I need to elite for this one, and you know who you are..

I am reviewing another party's eQuest model submitted for LEED. The reviewer noted that the roof area far exceeded the actual building footprint.

Well, guess why? Somehow, the other party made several floors ROOFS instead of ceilings. I might be able to simply turn the exterior spaces into interior ceilings, but one roof (over an unheated underground garage) is partially uder the building and partially exposed to the "sidewalk/entrance" of the building.

The BIG Kahuena is this..if a space is crammed next to an adjacent space and one of the spaces claims an Exterioir surface between them, does DOE-2 think that Exterior surface is seeing outdoor conditions? Or does it ignore such a thin and merely considers the heat transfer between the spaces (like the wall/roof is NOT exposed to the outdoors)?

My approach is this (unless you disagree)..leave the Exterior wall/roof along and explain that the model (now in Detailed Edit form) would need major surgery to correct to show actual roof area. Having the "roofs" there versus floors will not change the thermodynamics of heat transfer.

I yield to the floor.

John Aulbach, PE




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