[Equest-users] Building Orientation Accuracy?

[Nick Caton]

With that extra background, and glancing at this new baseline, I can
guess where your analysis may have gone awry...

 

Your assumed behavior, that "energy spent cooling" ought to be higher
with the glass facing South, is certainly logical for a project in the
Northern Hemisphere, as the cooling season solar contributions ought to
be higher facing South (barring any shades, of course).  If you'll run a
180-azimuth parametric calc on your "North Baseline" most recently
uploaded, you can observe this is exactly the behavior being modeled
(check out SIM report LS-B to compare solar contributions for each run).

 

Where I think you're making a leap is assuming a higher "space cool"
consumption figures equal higher cooling loads.  If you'll check those
same reports, you'll find you actually do have higher peak cooling loads
when facing south.  The lower South-facing "space cool" energy
consumption figures come alongside higher "ventilation" consumption
figures - eQuest appears to be up-sizing your South-facing CFM's and/or
run-time instead of cooling coil/condenser capacities.  With some
additional inputs you may be able to lock-in the fan and airflow
capacities, which would force your condensers to do more of the fan's
work (higher coil capacities), resulting in a higher "space cool" total,
if that's what you'd like the reports to show.  Ultimately your
South-facing run may simply need to run your fans more often over the
year, so you may not be able to entirely avoid a higher ventilation
total...

 

Of note, for any orientation, it appears you have a significant number
of under-heated hours.  You've may want to review your equipment heating
temperature setpoints and/or space/equipment CFM inputs.  You may
already know this, but as an additional reminder: your classroom as
modeled is only going to interact with the exterior conditions on the
single exterior wall, as the other three "internal walls" simply model
space thermal massing and heat transfer to other spaces.

 

Best of luck,

 

~Nick

 

 

 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com 

 

From: Otto Schwieterman [mailto:oschwieterman at fhai.com] 
Sent: Monday, May 17, 2010 3:36 PM
To: Nick Caton; Paul Riemer; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Building Orientation Accuracy?

 

I want to thank everyone for their help.

 

 Originally, I created one north facing classroom and ran the
simulation, then I rotated it 180 degrees. The heating results were
acceptable but the cooling results were odd. The cooling consumption was
greater on the north facing orientation than the south facing
orientation. The weather file is Dayton Ohio so this does not make
sense. I then tried to copy the classroom and rotate one of the
classrooms so I had a north facing and south facing classroom. I did not
realize that eQUEST changed some of the plenum and interior wall values
when I copied the original classroom.

 

I am still trying to figure out why the north facing classroom requires
more cooling than when I rotate the building 180 degrees and essentially
have a south facing classroom. I would think that because of solar heat
gain the south facing classroom would require more cooling. I have
attached a simplified classroom (I did not copy so there should be no
room for errors).

 

From: Nick Caton [mailto:ncaton at smithboucher.com] 
Sent: Monday, May 17, 2010 4:25 PM
To: Otto Schwieterman; Paul Riemer; equest-users at lists.onebuilding.org
Subject: RE: [Equest-users] Building Orientation Accuracy?

 

Otto,

 

I just looked at your revised files - you are still modeling two
seemingly fairly different classrooms.  Note your "North" classroom has
adiabatic internal walls/ceiling and your "South" classroom has heat
transferring ones.  I haven't scoured for other differences that may
well be in there regarding schedule assignments and such - I don't know
of a fast way to do so.

 

If you're truly concerned with eQuest's ability to correctly account for
a varying azimuth and want to test it, you could make your task easier
by creating a square classroom with identical walls on each side and
observe identical results with 0,90,180,270 degree azimuths.

 

~Nick

 

 

 



 

NICK CATON, E.I.T.

PROJECT ENGINEER

25501 west valley parkway

olathe ks 66061

direct 913 344.0036

fax 913 345.0617

Check out our new web-site @ www.smithboucher.com 

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Otto
Schwieterman
Sent: Monday, May 17, 2010 3:07 PM
To: Paul Riemer; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Building Orientation Accuracy?

 

I fixed the differences and now I get the following results:

 

North Facing: Space Cooling: 4.1 MBTU, Space Heating: 21.7 MBTU

South Facing: Space Cooling: 4.3 MBTU, Space Heating: 18.7 MBTU

 

When I change the orientation 180 degrees, the results are:

North Facing: Space Cooling: 3.8 MBTU, Space Heating: 22.6 MBTU

South Facing: Space Cooling: 3.6 MBTU, Space Heating: 17.8 MBTU

These also seem incorrect for the same reason.

 

From: Paul Riemer [mailto:Paul.Riemer at dunhameng.com] 
Sent: Monday, May 17, 2010 3:56 PM
To: Otto Schwieterman; equest-users at lists.onebuilding.org
Subject: RE: Building Orientation Accuracy?

 

Otto,

Your north and south have different inputs.  I specifically noted
plenums temperature set points and plenum floor weight.

I suggest you clean it up and run it again.

Paul Riemer

Dunham

 

From: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Otto
Schwieterman
Sent: Monday, May 17, 2010 2:39 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Building Orientation Accuracy?

 

I have noticed that eQUEST does not accurately determine the cooling and
heating loads when rotating the building 180 degrees using the Azimuth
feature under the building properties in the detailed edit mode. I
created and attached a file where there are two classrooms. One
classroom faces north and one faces south. 

 

When I run the simulation I get the following results: 

 

North Facing: Space Cooling: 4.1 MBTU, Space Heating: 21.9 MBTU

South Facing: Space Cooling: 4.3 MBTU, Space Heating: 18.9 MBTU

 

When I change the orientation 180 degrees, the results are:

 

North Facing: Space Cooling: 3.9 MBTU, Space Heating: 23.0 MBTU

South Facing: Space Cooling: 3.6 MBTU, Space Heating: 18.1 MBTU

 

When I rotate the site 180 degrees the north and south facing energy
consumption is different (they should be exactly the same). Also, the
space cooling does not make sense because the building's weather file is
Dayton Ohio and the south facing classroom should use more cooling than
the north facing classroom.

 

This makes me assume that eQUEST has a problem with building rotation in
the detailed edit mode. 

 

Please check to see if I am assuming this correctly because this will
affect every LEED project.

 

Otto Schwieterman

 

 

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Fanning/Howey Associates, Inc. has taken reasonable precautions to
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