[Equest-users] Scale modeling

Shaun Martin smartin at shaunmartinconsulting.com
Tue Apr 10 10:16:41 PDT 2012


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] On Behalf Of Eurek, John
S NWO
Sent: Tuesday, April 10, 2012 9:31 AM
To: 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] On Behalf Of Karen
Walkerman
Sent: Monday, April 09, 2012 4:18 PM
To: Stefano Moret
Cc: 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> 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 ad3.ucdavis.edu>  

	 


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