[Equest-users] Questions about shading effect simulation with eQUEST and DOE-2, Hope your help!

[Nick Caton]

Hi Lei Lei,

 

I can't say whether eQuest/DOE2 is the ideal tool for your research
(that's a question better answered by someone with cross-platform
experience), but from my limited experience I think your results are not
necessarily unreasonable.  Note that while eQuest/DOE2 can model the
shading and solar reflective realities present in real world buildings,
it does not explicitly model any changes to the wind behavior incident
on a building.  You may wish to address whether you do or do not intend
to account for the effects of windspeed on infiltration/envelope
U-values while exploring the shading effects of nearby buildings.

 

1.  In general, it would be odd if any set of building shades had an
equal effect on space heating and cooling consumptions.  The magnitude
of a fixed shade's effect on a building's loads changes with the angle
of the sun, which in turn changes between the heating and cooling
seasons.  Further, most buildings are either "cooling dominated" or
"heating dominated" due to a combination of their climate, internal
loads and envelope design.  As an example, some buildings will have a
minimal effect on their heating loads from building shades as they're
highly insulated, have significant internal loads and as such don't need
the additional solar loads in the winter to begin with.

2.  I can only speculate as this could be the result of a number of
things, but perhaps a location with less sun annually would observe a
relatively higher impact from losing that heating source during the
winter?  Have you confirmed the areas you are defining as "higher solar
radiation" reflect that in the TMY2 data you're using?  Are the effects
of daylighting controls skewing your results?  I'm guessing your
locations might be within Japan based on your university which I
understand has a very wide range of climates from Kyuushuu (subtropical)
to Hokkaido (brr!) - if the goal is to isolate the effects of building
shading, you may do well to first observe the differences within a
single climate zone before moving your model all over... 



A good amount of this is speculative (shots in the dark) - but  if all
else fails there's always the lingering possibility that what's expected
is wrong.  Sometimes our models can teach us things when we least expect
it!

 

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: equest-users-bounces at lists.onebuilding.org
[mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of lei lei
Sent: Saturday, October 16, 2010 3:18 AM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Questions about shading effect simulation with
eQUEST and DOE-2, Hope your help!

 

Dear All:

Please excuse me for I'm taking the liberty of sending e-mail to you.
I'm a PHD student of Nagoya University. Could I ask some questions about
the application of simulation tool eQUEST and DOE-2?  
 
In my research, I used the eQUEST to analyze the shading effect from
nearby buildings. However the simulation result seems to be not
reasonable. I wonder whether the eQUEST is suitable for these kinds of
shading effect studies. Could you please give me any suggestions?
 
The research is about a building in the middle of a parallel layout
buildings group. It is focus on the building shades of nearby buildings.
In order to analyze the energy implication due to shading effect from
nearby buildings, rectangle shades are established nearby the simulated
building with BUIILDING-SHADE. The shading effect is denoted by the
absolute difference between the energy consumption of the building
without surrounding building shades and the building with surrounding
building shades. The same model was applied to a lot of cities (TMY
data). It was found that:
 
1)      For all the cities, the more the shading effect on space cooling
the less the shading effect on space heating. (But, in fact, for most of
cities, when the solar radiation in summer is much, the solar radiation
in winter is relatively much also.)
2)      the shading effect in some cities with less solar radiation is
much more than that in some cities with more solor radiation.( But in
the documents of DOE-2, only the solar radiation will affect the shading
effect, when all the other situations are same except weather data.) 
 
Could you please give me any suggestion to explain these results? Or are
the DOE-2 and eQUEST not suitable to do these kinds of shading effect
analysis? If so, could you give me any advice about any software can do
the simulation of nearby shading effect on building use?
 
with best regards,
-- 

yours sincerely,
 
Lei LEI


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