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<div class="moz-cite-prefix">Simge, <br>
<br>
I feel compelled to respond since you mentioned me so prominently
in your post :-)<br>
<br>
I think you're bringing up a very germaine question, and indeed
it's one that in my opinion needs further study, i.e., <br>
how does EnergyPlus compare with eQUEST or other building energy
simulation programs in their modeling results?<br>
<br>
The LBNL paper you cited is a summary paper from a SimBuild
Conference in 2008 that only skimmed the findings from a<br>
year-long effort supported by the California Energy Commission.
I've put the full report on the Web, along with a later study<br>
I did last year as part of an EnergyPlus Feasibility Study by
AutoDesk done for Southern California Edison that you might find<br>
equally interesting:<br>
<br>
<a class="moz-txt-link-freetext" href="http://www.whiteboxtechnologies.com/download_AutoDesk_EP_feasib_rpt.htm">http://www.whiteboxtechnologies.com/download_AutoDesk_EP_feasib_rpt.htm</a><br>
<br>
The second study was under wraps for a long time, but I received
clearance from SCE to release it two months ago.<br>
My part of the study is strictly the EnergyPlus to DOE-2.2
comparison pp. 57 -98, and I have no opinions one way or <br>
the other in respect to the rest of the study. My task was to take
several DEER prototypes (office, residential, and retail)<br>
modeled in eQUEST/DOE-2.2 and convert them to EP 7.X. Compared to
what I saw in the 2007 study, the discrepancies<br>
in heating energy consumption were even more striking, probably
because all the buildings were modeled in southern <br>
California climates. I was getting consistently from a 5:1 to a
20:1 difference in heating energies (DOE-2 high, EP low).<br>
<br>
Following up on Jeff's earlier comment, diagnosing the differences
between two simulation programs requires a lot of <br>
time, experimentation, and often in-depth study of the source
codes. In the 2007 paper, I mentioned somewhere between<br>
15 and 20 areas of modeling differences with significant effects
on the results. <br>
<br>
It's been 7 years since the first study, and I've been
disappointed by the lack of progress. Some of it is
understandable, since <br>
speaking frankly, there are a very limited number of people with
sufficient knowledge and interest across two programs to make
heads or tails out of these comparisons. But it is a very
important issue, not just from technical curiosity, but because a
lot of<br>
money have been invested based on what these programs say, so if
they give significantly different results, policy makers would <br>
like to know what's going on and ideally, what is the ground
truth? <br>
<br>
I don't want to sound like a modern-day Cassandra, and I don't
have enough resources or time to pursue this as a private<br>
adventure. However, I hope that public institutions will see the
need and benefit, and support some serious work in this area.<br>
<br>
I know that you (Simge) or I are not the only people who've
wrestled with this problem. I would like to hear the experiences
of<br>
others (not you, Jeff, I already know what you would say :-) ).
Since all the efforts I've heard of are going from eQUEST<br>
to EnergyPlus, not the other way around, the domain knowledge is
probably higher on the eQUEST/DOE-2 side. Therefore,<br>
it would be most valuable to get the EnergyPlus experts to chime
in on the nuances of EnergyPlus modeling of which we<br>
may be lacking. For the same reason, you might consider posting
your message to the EnergyPlus_Support bulletin board<br>
as well. <br>
<br>
See, Simge, now you got me wasting a couple of hours on a Friday
afternoon! <br>
<br>
I'm not sure when I would have time to look at your input files,
but if I see anything I'll let you know.<br>
<br>
Joe<br>
<br>
<br>
<br>
<br>
On 5/1/2014 1:35 PM, Simge Andolsun wrote:<br>
</div>
<blockquote
cite="mid:CAHm8iRMJeJ6bkYh5uD5sYKeTcE-G5Q-gVsEN-pt79hDEr4uc1A@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>Dear eQUEST users (Particularly Dear Joe Huang),</div>
<div><br>
</div>
<div>Please find the attached eQUEST and EnergyPlus files. They
represent identical cases for comparison of the two programs.
The runs are conducted for Los Angeles. The heating and
cooling consumption of EnergyPlus file are, however,
unreasonably higher than that of EQUEST. It is particularly
strange that heating occurs in early morning time during the
summer in EnergyPlus whereas no heating occurs in eQUEST
during these hours.</div>
<div><br>
</div>
<div>We need our results not to deviate extremely from eQUEST
when we start using EnergyPlus. That is why, I am conducting
this comparative analyses for cases representing identical
conditions. I would appreciate it very much if you could
examine these files and let me know whether there is anything
I can do to make the results of these cases in the two
programs as close as possible to each other.</div>
<div><br>
</div>
<div>Dear Joe Huang,</div>
<div><br>
</div>
<div>Please see the attached charts that show the hourly
variation of temperatures in the system nodes and hourly
energy consumption. There is definitely something weird going
on in the early morning hours when the system just starts
working. I have read your paper in the link below. Below is a
section from your paper that I have paid particular attention
to. Might I be having a similar issue in my case? </div>
<div><a moz-do-not-send="true"
href="http://gundog.lbl.gov/dirpubs/SB06/huang.pdf"
target="_blank">http://gundog.lbl.gov/dirpubs/SB06/huang.pdf</a>.
</div>
<div>
<p align="LEFT"> <font face="Times New Roman"><font
face="Times New Roman"><i>"Heating to the cooling
setpoint</i></font></font><font face="Times New Roman"><font
face="Times New Roman">. Temperature plots revealed that
at times during the shoulder seasons, <em>EnergyPlus </em><font
face="Times New Roman"><font face="Times New Roman">had
difficulty in picking between the heating or cooling
season control logic. This resulted in the supply
air being heated to the cooling, rather than the
heating, setpoint during the morning hours. This
problem was corrected by improving the setpoint
manager in <i><font face="Times New Roman"><font
face="Times New Roman">EnergyPlus</font></font></i><font
face="Times New Roman"><font face="Times New
Roman">."</font></font></font></font></font></font></p>
<font face="Times New Roman"><font face="Times New Roman">
<p>Looking forward to hearing from you,</p>
<div>Best Regards,</div>
<div>Simge Andolsun, PhD.</div>
</font></font></div>
</div>
<br>
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