[Equest-users] Scale modeling

[Stefano Moret]

Dear all,

I’ve proceeded in the last days in my research for model validation and building prototypes which could serve as reference models for my research.
I finally found what I was looking for, and it looks like this has been the goal of a DOE project concluded in 2008. In the website I linked below, there are listed some models of commercial building prototypes which have demonstrated to fit most of the commercial buildings in the US, and which could serve as a starting point for modeling energy efficiency measures without the risk of having results dependent on the specific modeling assumptions, of course within reasonable ranges. There are also the IDF files which serve as input for E+.
To recall the elephant and the mouse metaphor, here there’s probably a good reference for consistent mice and elephants prototypes, and that was exactly what I was looking for.

Here’s the website for your interest:

http://www1.eere.energy.gov/buildings/commercial_initiative/reference_buildings.html

Thanks again for your hints, and best regards
Stefano

--

Stefano Moret
California Lighting Technology Center<http://cltc.ucdavis.edu/>
University of California, Davis
633 Pena Drive
Davis, CA 95618

530-747-3846
smoret at ucdavis.edu<mailto:smoret at ad3.ucdavis.edu>




From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of joe at thespinnakergroupinc.com
Sent: Tuesday, April 10, 2012 11:06 AM
To: joe at thespinnakergroupinc.com; Shaun Martin; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Scale modeling

And of course note you have multiple floors to deal with when you scale up...

On second thought a better way to scale would he to maintain the ratio of
length x width / height x ((2 x length) +  (2 x width))

If height is constant then a 10x10 space scaled up ten times floor area would best scale to something like 194x5.1 (excuse calculations, no calculator doing this at red lights).  Where other issues arise like the exposure of the long face will make a big impact.

If building modeling could be scaled for certain constants this easily them we could do it with little paper wheels like ductulators.

Fun to think about though!

Joe Fleming, PE, BEMP, LEED AP BD+C
----- Reply message -----
From: "joe at thespinnakergroupinc.com<mailto:joe at thespinnakergroupinc.com>" <joe at thespinnakergroupinc.com<mailto:joe at thespinnakergroupinc.com>>
To: "Shaun Martin" <smartin at shaunmartinconsulting.com<mailto:smartin at shaunmartinconsulting.com>>, <equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>>
Subject: [Equest-users] Scale modeling
Date: Tue, Apr 10, 2012 1:44 pm

If the building is being scaled by some magnitude, then all dimensions need to be scaled equally.  Otherwise, as has been mentioned in the previous emails, the ratio of envelope surface area to floor plan area will change.

A 10x10x10 building, (heat/cool load-wise), will scale better to a 100x100x100 then it would to a 100x100x10, because the ratio of floor space to envelope area is maintained.  Although only the top floor will have roof load.  And a skylight will only effect the top floor of the larger scale building.

Can you change from a skylight to a window with daylighting?  This would scale better.

Joe Fleming, PE, BEMP, LEED AP BD+C

----- Reply message -----
From: "Shaun Martin" <smartin at shaunmartinconsulting.com<mailto:smartin at shaunmartinconsulting.com>>
To: <equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>>
Subject: [Equest-users] Scale modeling
Date: Tue, Apr 10, 2012 1:16 pm



Hi Stefano,

John's right on point (especially the elephant part).   The results likely
represent some sort of curve, and are probably multivariate.  My suggestion
would be to model large, medium and small scenarios and do hourly reports of
the loads to see what is happening at different outside temperatures.

Shaun Martin


-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org>
[mailto:equest-users-bounces at lists.onebuilding.org]<mailto:[mailto:equest-users-bounces at lists.onebuilding.org]> On Behalf Of Eurek, John
S NWO
Sent: Tuesday, April 10, 2012 9:31 AM
To: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] Scale modeling (UNCLASSIFIED)

Classification: UNCLASSIFIED
Caveats: NONE

Shrews must eat 80-90 % of their own body weight in food daily.  An elephant
eats about 5% of their own body weight in food daily.

The surface area to mass ratios are vastly different.  Heat loss, metabolism
(internal loads) and fur are very different.

If an elephant had the fur of a mouse it would die from overheating.

You can't model a small building and try to extrapolate the results to a
large building.

John Eurek

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org<mailto:equest-users-bounces at lists.onebuilding.org>
[mailto:equest-users-bounces at lists.onebuilding.org]<mailto:[mailto:equest-users-bounces at lists.onebuilding.org]> On Behalf Of Karen
Walkerman
Sent: Monday, April 09, 2012 4:18 PM
To: Stefano Moret
Cc: equest-users at lists.onebuilding.org<mailto:equest-users at lists.onebuilding.org>
Subject: Re: [Equest-users] Scale modeling

The short answer is that every building is different, and there is no
"typical" model that will fit them all.

As you mentioned, the ratio between lighting/cooling/heating changes
depending on the size of the building.  I'm willing to guess that this is
because the core zones that have very little need for heat get much larger
in relation to the perimeter zones.  Also, the building energy needs will
change depending on orientation and global location.

I would suggest that you take a slightly different approach - try to come up
with values that are representative for different types of spaces.  You
might do say:

1.  A perimeter office space with XX% glazing (run for North, East, South
and West exposures) 2.  A core office space with no skylights 3.  A core
office space with XX% of roof area as skylights 4.  A core manufacturing
space???
5,6,7....

Run each model in the applicable climate.  Then, if you have an office
building that is 70% core and 30% perimeter space, you'll have a better
understanding of the building.  This is still a very rough approximation,
but should get you farther than trying to model one "typical" building.

--
Karen



On Mon, Apr 9, 2012 at 4:57 PM, Stefano Moret <smoret at ucdavis.edu<mailto:smoret at ucdavis.edu>> wrote:


Dear all,



I've recently played around quite a bit with E-quest to simulate the
effect of dynamic fenestration on building energy consumption.

For these simulations I've been using a very simple office model
with a skylight on the top as a test-bed for my calculations (with default
system for HVAC and daylighting controls with dimming for lights) but,
observing the values I'm obtaining in output, I see that the values I obtain
for lighting, cooling and heating consumption make sense relatively, i.e. if
compared to themselves in different conditions, but are sometimes of totally
different order of magnitude if compared to each other (lighting/cooling
loads are often much higher than heating, by orders of magnitude),
especially when scaling up the model to bigger sizes. This way, it's very
difficult to see the effect of a variable change on the total energy
consumption.



I know the model I'm using is very idealized, but is there any
variable that I can act on in order to obtain a model which has energy
consumption values more similar to a real building? For example, is there a
"suggested" size of the building that gives better results? Or maybe
simulating a single room in a large building gives more realistic results
than the single room alone?

My point is that I would like to have a model whose results in scale
might be consistent when applied to bigger buildings.



Thanks for your hints and suggestions,

Stefano



--



Stefano Moret
California Lighting Technology Center <http://cltc.ucdavis.edu/>
University of California, Davis
633 Pena Drive
Davis, CA 95618



530-747-3846
smoret at ucdavis.edu<mailto:smoret at ucdavis.edu> <mailto:smoret at ad3.ucdavis.edu>




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Classification: UNCLASSIFIED
Caveats: NONE


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