[Equest-users] Zones with different height

[Jing Hong]

Hi Bruce,

I've attached the sketches of this building. As you see, the northeast
portion is higher than the rest, But actually they are in the same zone. I
had two shells attached to each other and deleted the overlapping walls. So
you think I should make is in one shell, and just set the plenum in
different heights?
Thank you so much for your time and effort.

Jing

On Thu, Nov 9, 2017 at 12:41 PM, Bruce Easterbrook <bruce5 at bellnet.ca>
wrote:

> You shouldn't have overlapping walls.  There should be a wall between the
> 2 zones that is common and in 2 areas if you used the plenum setup to deal
> with the height differences.  It will be an interior wall initially but can
> be changed to exterior if you delete exterior walls in the second zone.
> You will also need to make the ceiling below a roof which means what you
> need to reflect the zones in the floor above and the floor below.  I assume
> you are dealing with a portion of the floor with the different foot prints
> from a week or so ago.
> Normally I don't use the 2 shell method but sometimes it was the only way
> forward and have.  It seemed to me you wouldn't have to do that in this
> case.  Having the 2 zones allows you to have them at the same conditions or
> different.  By adding in the plenum spaces gives you 4 zones.  What you are
> doing is trying to is mimic the constructions and boundary conditions.  By
> that I meant is the surface adjacent to another zone or to the exterior.
> That is the only condition you need to worry about at this time.
> A few things are coming back but it has been a while since I have done
> this.  To eQuest a wall is just a line, typically taken as the centre line
> of the wall.  It has no thickness.  This can trip you up if you are using 2
> shells.  They have to occupy the same space before you delete one.  I know
> I had to play with the wireframe to make sure I was deleting the right
> wall.  I also remember sometimes having to adjust the polygons as they have
> a direction.  That may present itself when changing an interior wall to
> exterior.
> In short I'm not exactly sure what you are trying to do.  A picture or
> sketch might help.  Some of these work arounds are tricky and my time is
> short.  I'm working from memory to sketch the concept for you.  So there
> might be a few details that have escaped me.
> Bruce
>
>
>
> On 11/9/2017 11:47 AM, Jing Hong wrote:
>
> Hi Bruce,
>
> Thanks for your patient explanation. Yes, I did split a room into two
> zones (and also two shells). And then deleted the overlapping exterior
> walls, which should not exist.  When you said "reflect what is actually
> happening at the boundary". Does that mean you make the adjacent two
> zones the same condition and work as one zone?  Could you please clarify
> how to set that up? I really appreciate.
>
> Jing
>
> On Thu, Nov 9, 2017 at 9:21 AM, Bruce Easterbrook <bruce5 at bellnet.ca>
> wrote:
>
>> Hi Jing,
>> It is a little difficult to tell from your explanation of what you are
>> doing but it doesn't seem like the correct approach to me.  eQuest will
>> allow you to have different zones for the conductive/thermal model and then
>> different zone configurations for the HVAC model.  Differing constructions
>> I do as separate zones.  It makes putting all the boxes together.  All
>> surfaces have to be accounted for.  Everything has to conduct to another
>> zone or to the exterior.  Even if you miss a 1" strip the model will throw
>> errors.  When you build your model I find it better to err on the side of
>> too many zones.  Your picks of areas for zones need to initially reflect
>> how the building is constructed but also thinking of how the building is
>> going to be heated and cooled.
>> I would split that zone you are working on into 2.  Each portion will
>> cover the different ceiling height.  Give each zone a plenum and make it
>> the height of the difference in the zone heights.  That will allow you to
>> split the wall into 2 different sections and give each one different
>> properties.  It also gives you 2 ceilings.  Make the one with the higher
>> ceiling an air wall type boundary.  Adjust the plenum wall construction to
>> reflect what is actually happening at the boundary.  Adjust the ceiling
>> construction of the room/plenum of the lower zone, delete what you don't
>> need.  Later when doing the HVAC you can put both of these zones on the
>> same unit.  So you don't necessarily zone a building according to the
>> proposed HVAC system.  You have to take the discontinuities into account
>> and add zones to make it easier to model.  Every thermal box has to be
>> perfectly closed or eQuest will stall on you.  You are lucky it tossed
>> warning messages, these are clues to what you have missed.  You are close.
>> It is really bad when you crash and don't get clues.
>> Good luck.  You seem to be coming along fine.  One other tip, stay in the
>> detailed wizard as long as possible.  Ignore windows and just leave them as
>> general areas until you get everything else worked out.  Save files lots so
>> you can go back if something happens.  They are like restore points.  The
>> closer you are to the crash the less work you lose.  Plus, projects change
>> once everyone starts looking at the modelling results, you find more
>> efficient ways and need to be able to adjust your model.
>> Bruce Easterbrook P.Eng.
>> Abode Engineering
>>
>>
>> On 11/9/2017 9:17 AM, Jing Hong via Equest-users wrote:
>>
>> Dear All,
>>
>> I built up two shells for a room with two different ceiling heights. And
>> then deleted the exterior walls. Now the BDL Load File Log shows some
>> warnings of no delayed wall, no delay ceiling for those spaces. Should I
>> ignore those warnings? Or try to fix them? Am I doing correctly to deal
>> with a zone with different heights in this way?
>>
>> Thanks,
>>
>> Jing
>>
>> --
>> PhD Candidate, LEED AP BD+C
>>
>> School of Architecture and Urban Planning
>> University of Wisconsin-Milwaukee
>>
>>
>>
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>>
>>
>
>
> --
> PhD Candidate, LEED AP BD+C
>
> School of Architecture and Urban Planning
> University of Wisconsin-Milwaukee
>
>
>


-- 
PhD Candidate, LEED AP BD+C

School of Architecture and Urban Planning
University of Wisconsin-Milwaukee
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