Understanding Floors

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To All,

I just want to make sure I understand the properties behind floors. If you
have a square building volume with a smaller square inside it that has 2
levels. EG:- an atrium as main space with 2 levels that are offices. There
will be a total of 3 floors in your model. Atrium floor, first floor office
and second floor office. Each of these will have a designated floor to floor
height. You cannot put one zone inside another on the same floor.

Is this correct?

Thanks,

PETER HILLERMANN

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Peter, I think you might be leading yourself into some unnecessary
confusion with your word choices...

eQuest has 3 distinct entities:

- Shells are simply groups of spaces

- Spaces are geometrical volumes, which may or may not have
floors, walls, ceilings, windows, etc. tied to them. Internal loads /
daylighting / occupancies are attributed to spaces.

- Zones are simple entities that include one or more spaces,
with additional HVAC attributes like thermostat and airflow specifics.

You're using "floors" to interchangeable discuss all the above, it
seems. For clarity when discussing eQuest, "floors" are merely the
constructions we walk on, normally one attribute of a "space."

All that said, it's entirely possible to model a "box within a box," as
you're describing. You are limited in the wizards (by their nature)
with regard to defining zones/footprints... the best approach depends on
the nature of the space footprints you want to model. If it's very
simply two stacked cubes enclosed within a larger cube, I'd personally
model one shell, with one space carved out of the middle. Then I'd use
the detailed mode to shrink that space volume and partition/ceiling
dimensions to match the first floor office, then copy the entire space
and its componenents for the second floor. I'd adjust the largest
cube's volume (it's a space property) to correct the conditioned volume,
and be sure all partitions are correctly associating the three spaces
together... With all spaces sorted out, ensure your three spaces are
correctly grouped with regard to "zones," for association with your HVAC
system(s).

Clear as mud =)?

NICK CATON, E.I.T.

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Nick,

Thanks again. Can you stack a space in a zone?

Thanks,

PETER HILLERMANN

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Hey Peter,

If by "stack" you mean place one space geometrically over another, the
answer is yes. If you mean to ask whether zones can group spaces in
different elevations, the answer is also yes.

However, I would like to hammer out your wording again to be sure we're
on the same page! I think you meant to ask "Can you stack a space in a
shell?" Spaces are normally "inside" shells in a geometrical sense, as
they are generally within the shell footprint/boundaries.

Zones, in contrast, have nothing to do with geometries - they are simply
groupings of spaces with some extra HVAC/airflow properties tacked on.
Those spaces could be all over the place - at different elevations,
within different shells... pretty much any combination from my
experience.

Best of luck! If you are getting tripped up, remember a picture is
worth a thousand questions (?)...

~Nick

PS to all: The SD/DD Wizards are, in my mind, kinda misleading with
regard to helping new users understand the distinction between "space" &
"zone." Some work in detailed mode will eventually lead you to
understand, but the Wizard screens inconsistently interchange the terms
and may cause others confusion in the long run... See my description
below for a simple breakdown if you are cutting your teeth on eQuest ;).

NICK CATON, E.I.T.

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Nick,
How do you group multiple spaces in one zone? I always thought you could do only one space per zone.

[cid:image001.jpg at 01CB114B.9B95DB60]

Vikram Sami, LEED AP

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I'm with Vik- I thought it was only one space to one zone, but if someone
has a new way of things, please share...

pkg

Pasha Korber-Gonzalez's picture
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perhaps the question is "are you referring to a zone or a zone group?"

in the ddwizard you can specify multiple zones into a zone group. so if
every space, i.e. every room, is it's own zone, then you could add
multiple spaces to a zone group. otherwise you're just making a thermal
zone composed of multiple spaces. as far as i know.

Patrick J. O'Leary, Jr.'s picture
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Eek - My own explanation of the terminology is mixed up - doh!

When I say "group spaces into one zone," I'm mis-speaking, and really
talking about how one can "group zones under one system" in detailed
mode.

If I may attempt to redeem myself... here's a revised set of my layman's
definitions:

- Shells are simply groups of spaces

- Spaces are geometrical volumes, which may or may not have
floors, walls, ceilings, windows, etc. tied to them. Internal loads /
daylighting / occupancies are attributed to spaces.

- Zones are simple entities that include one space, with
additional HVAC attributes like thermostat and airflow specifics. Zones
(and their corresponding spaces) may be grouped any which way under a
System.

With my tail between my legs,

NICK CATON, E.I.T.

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I can put more than 1 zone into a space. When you go to the HVAC tab it will
show your building together within that space. The problem I had was
overlapping zones, one stacked on top of the other with the same ceiling
height so I broke apart my office into 2 different floors as you can see by
the images. That's where my question came from.

Thanks,

PETER HILLERMANN

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Peter,

What do you mean by "I can put more than 1 zone into a space"?

Demba.

Demba Ndiaye's picture
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OK, Answering my own question. The "Floor" is the floor to ceiling height
and floor to roof deck height. The "space" resides inside the floor which
only has a ceiling height allowing for plenum spaces if required or not (so
if your ceiling has insulation and the envelope insulation ends there your
space would be shorter than your floor height). You can have more than one"
space" per "floor" however the "floor" only consists of 1 floor to roof deck
height not multiple. Therefore, if you have structures with multiple roof
heights you have to break them out into multiple "floors" to give their roof
decks different heights. Inside the space you define the polygons that make
up each individual shell item. IE:- that's where your wall, door window roof
or floor polygons go etc. and how they know which space and floor they are
linked to. The space that you have created is then linked to HVAC
requirements which make up a "zone". You can have more than one "space" per
"zone" and different floor levels can connect to the same HVAC zone if you
need them to.

In other words you can have the same HVAC unit cooling 2 different buildings
if it needs to, or if you want to cool floor 1, 3, 5, 7 with one unit and
2,4,6,8 with the other you can. The shell is merely a graphic representation
of the floors and spaces working together as one. Therefore if your shell
looks funny you messed up creating a polygon and connecting it to the
correct space (because I just got this error). HVAC "zone" has nothing to do
with the geometries except analyzing them for HVAC loading.

Therefore I would suggest if you have a building with complex geometries to
use sketchup or "some other single plan software" import the geometries and
build your spaces in eQuest.

PS:- if you get your floors and spaces incorrect your zones won't matter and
your model will not give the correct readings. Your roof might be at 18 feet
but your floor reads 27 feet. This also only applies to people building
their models in detail mode not in the wizards. I know there are probably a
large number of users using the wizard to build their geometries.

Thanks,

PETER HILLERMANN

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Sorry wrong terminology. By space I'm going back to what I said "Floor."
When you open eQuest property tab for a designed floor it actually says
floor properties. These define the floor to ceiling and roof deck heights.
You can place multiple spaces in it and zones. All this applies to detail
mode and not the wizards. All my models are created in detail mode I do not
use the wizard for anything. So I apologize for any confusion.

Peter Hillermann's picture
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So Peter, when you say Floor, you are really referring to "Shell", which is
what the right terminology is in terms of eQuest. Note: you can define
multiple floors within a shell.

The wizard is not a completely useless tool, and when you set up your
buildings (i.e. building footprint & zoning) at the very least can be done
super easy in the wizard. Most of your detail work might need to be done in
the detailed edit mode, but don't underestimate the benefits of the wizard
inputs too. Efficiency is key for both the building design and the
simulator(s).

pkg

Pasha Korber-Gonzalez's picture
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I did not say the wizard was useless. I just don't want to confuse anyone.
Attached is my model to give a better understanding of where I'm coming
from. I have nothing against the wizard but I really don't want to confuse
any other users that are using the wizards. My questions are based on
terminology coming directly from the component tree in detail mode. You will
notice under building shell a child component for a floor is a space.

Please do not misconstrue any of my comments as fact or that I know what I'm
doing. I like many others am trying to learn the software on this forum.
Again I mean no disrespect with any comments I make, they are just opinions
and I'll try keep them to a minimum.

Peter Hillermann's picture
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Peter, I know you didn't say anything against the wizard. I just inteded to
remind others that there is much efficiency in using the wizard inputs, and
I am continuously taught by others on new ways to use the wizard to increase
user efficiency. (Thanks Dan W.)

This whole forum is about clarification, so don't worry about getting too
bogged down with it. bWe all learn to be more clear in writing our questions
when we need help--it's part of the learning process...

pkg

Pasha Korber-Gonzalez's picture
Joined: 2011-09-30
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Just to add to what Pasha and Nick are saying, you can also use
multiple shells to define a floor. Each of these shells is composed of
a base polygon, the space. Using the DD wizard you can break this space
into numerous zones or polygons. You can also use the DD wizard to
re-arrange these zones/polygons in any fashion you choose into different
HVAC zones. eQuest will default to 1 HVAC zone per base polygon or
space. Using the DD wizard you can create new HVAC units and take zones
from the base polygon/HVAC system(s) to make new HVAC zones. This is
totally separate from the polygons, you are just grouping the polygons
into a system.
The beauty of eQuest is the DD wizard and the visual interface to
create your model with an AutoCad dwg import feature. This is where the
human brain blows away any computer on the planet. The geometry of your
building is what drives the way you manipulate eQuest to create your
floors, shells and polygons. To be efficient you have to take a serious
look at your building before you start entering data. Each polygon has
6 planes which have a thermodynamic exposure. You have to build your
building out of these polygons so you get your exposures correct. The
floor above will have an impact on how you build the floor below because
you have to get your exposed surfaces correct, ie roofs, exterior walls.
The unfortunate part of eQuest is to make it easy you need AutoCad,
a very expensive program. But you can use any cad program and build a
wire-frame to create your vertices's, you just have to input them by
hand on page 2 but easily doable. Even with AutoCad I still produce a
wire-frame to keep track of my input and correct maybe 15% of my cad
snap points. Another little trick is to know where all your interior
polygons/zones are going to intersect your base polygon/space. When you
input your base polygon/exterior shell put a vertex at each of these
intersection points as you go around the exterior. It will make
snapping to them much easier later when you enter your zones/polygons.
Remember computer programs are really dumb. A to B, B to C...
eQuest will let you input junk, as long as you follow it's rules, it
will happily simulate this junk, and of course output junk. This is
where Engineering comes in, and it starts with meticulous input from a
plan, little bricks (polygons) to build a building model. Take a little
time at the start to make a plan, do a wire-frame, revise your plan, and
then go. It is like chess and you have to think ahead. If your
geometry is junk, so is everything else.
I use the DD wizard extensively and almost exclusively, never edit
polygons in the detailed edit, rarely edit the INP file, and only for
tricky things, or I have made a mistake and have to recover from it.
The DD wizard is a great tool.
Bruce Easterbrook P.Eng.

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I think this is where we should consistently saying that each space creates
it's own unique "thernal zone". These thermal zones are later assigned to
HVAC zones. No problemo.
We just need consistency.
Carol

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equest would be a much more efficient program if it didn't force you
to do 3-D modelling. Many buildings have no self-shading
(rectangular boxes). For this type of building all you need to
specifiy is the area and azimuth of each exterior
surface. Underground walls and floors only need to have the area defined.

It would be great to have a check box in equest so that when you
start, you can select 2-D modelling and get rid of the software bloat.

Chris Jones

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