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Jeremiah,<br>
<br>
I'm not quite sure what you're driving at, but performance curves
are used throughout DOE-2 and EnergyPlus to model the performance of
HVAC equipment. In fact, if my memory is correct, the chiller model
in EnergyPlus is taken directly from DOE-2.<br>
The performance curves are not a "theory", but empirically derived
equations that map performance as functions of the ambient air
conditions and the part-load-ratio at that time step based typically
on manufacturers' test data. so yes, these curves do reflect<br>
real world conditions. Take out these curves, i.e., assume that all
equipment perform the same under all conditions, and there wouldn't
be much point to simulating the system at all.<br>
<br>
But getting back to Peter's hypothesis, I don't think the increase
in cooling energy is due only to the shape of the equipment curves.
I think it's a combination of that plus the zone air flows, and the
COOL-CONTROL. This last item is particularly tricky in a moderate
cooling climate. We have to remember that air-handling systems are
not ideal - if you reduce the cooling load in a zone that's not the
warmest without changing the relative zone air flows, you may just
overcool that zone and in the worse case increase reheat energy.
The federal government learned that back in the early 70's when in
response to the Arab Oil Embargo<br>
they asked that all government offices raise their cooling setpoint
temperatures as an energy saving measure.<br>
<br>
Joe<br>
<br>
On 7/15/2012 6:51 PM, CleanTech Analytics wrote:
<blockquote
cite="mid:CALKTE9TC3Hr9K_h-dU3BhGZJp8a0FOOqtrRVqxTSPAxDv1Xicg@mail.gmail.com"
type="cite"><font style="color:rgb(51,102,102)"
face="verdana,sans-serif">So if the curve theory is correct I
wonder if this would happen </font><font>in </font><span
style="color:rgb(51,102,102);font-family:verdana,sans-serif">other
modeling software</span> <font color="#336666"><font
face="verdana,sans-serif"> or more importantly in the real
world>? --reduce internal gain and increase cooling
consumption-- or if this phenomena is only possible in
the virtual world of eQuest..,,</font></font>
<div>
<font color="#336666" face="verdana, sans-serif"><br>
</font></div>
<div><font color="#336666" face="verdana, sans-serif">Joe-Liam-Paul
what do you think >?<<br>
</font>
<div><font color="#336666"><font face="verdana,sans-serif"><br>
</font></font></div>
<div><font color="#336666"><font face="verdana,sans-serif"><br
clear="all">
</font></font>
<div style="text-align:left"><font color="#999999"
face="verdana, sans-serif"><i>Jeremiah D. Crossett</i></font></div>
<div style="text-align:left"><font color="#999999"
face="verdana, sans-serif"><i>CleanTech Analytics</i></font></div>
<div style="text-align:left"><font color="#999999"
face="verdana, sans-serif"><i>503-688-8951</i></font></div>
<div>
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href="http://www.cleantechanalytics.com" target="_blank"><font
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<div style="text-align:center">
<br>
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<p dir="ltr"
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<br>
<br>
<br>
<div class="gmail_quote">On Sun, Jul 15, 2012 at 5:47 PM,
Peter Baumstark <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:pbaumstark@sbcglobal.net" target="_blank">pbaumstark@sbcglobal.net</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<div
style="font-family:arial,helvetica,sans-serif;font-size:12pt">It's
an interesting problem. With this model, no matter
what I do, if I manually change the SHGC or SC (if I
use the U-Value method), or if I select different
glazing types from the library (with different SHGC
values), no matter what face of the building I change
it, I get an increase in overall monthly energy use
with a lower SHGC.<br>
<br>
I built the model through a zone by activity area
method that pretty closely matches the various zones
of the building. It's a VAV with terminal reheat
system (1995 Trane Intellipaks), and I entered actual
economizer, static pressure and SAT settings. Airflow
matches as-built design drawings.<br>
<br>
I tried using other eQUEST models I've built for other
customers using similar methods, changed the location
to San Jose, and ran window cases and results were as
expected.<br>
<br>
I'm coming to believe that one issue with the building
in question is the RTUs seem over sized relative to
the use patterns and internal heat gains. This
building previously had various lab areas, then was
purchased by another customer with lower internal heat
load rates, but they kept the same RTUs.<br>
<br>
Could it be possible that the lower heat gains from
better fenestration products could place the RTUs at a
more inefficient spot on its performance curve? I've
ran into similar issues with chilled water systems,
but never looked at DOE-2 performance curves for DX
units.<br>
<br>
Pete<br>
<div><br>
</div>
<div
style="font-family:arial,helvetica,sans-serif;font-size:12pt"><br>
<div style="font-family:times new roman,new
york,times,serif;font-size:12pt"><font
face="Tahoma">
<hr size="1"><b><span style="font-weight:bold">From:</span></b>
Paul Diglio <<a moz-do-not-send="true"
href="mailto:paul.diglio@sbcglobal.net"
target="_blank">paul.diglio@sbcglobal.net</a>><br>
<b><span style="font-weight:bold">To:</span></b>
Joe Huang <<a moz-do-not-send="true"
href="mailto:yjhuang@whiteboxtechnologies.com"
target="_blank">yjhuang@whiteboxtechnologies.com</a>>;
CleanTech Analytics <<a
moz-do-not-send="true"
href="mailto:jeremiah@cleantechanalytics.com"
target="_blank">jeremiah@cleantechanalytics.com</a>><br>
<b><span style="font-weight:bold">Cc:</span></b>
<a moz-do-not-send="true"
href="mailto:equest-users@lists.onebuilding.org"
target="_blank">equest-users@lists.onebuilding.org</a><br>
<b><span style="font-weight:bold">Sent:</span></b>
Sun, July 15, 2012 5:03:54 PM
<div>
<div class="h5"><br>
<b><span style="font-weight:bold">Subject:</span></b>
Re: [Equest-users] Unexpected Custom SHGC
Results<br>
</div>
</div>
</font>
<div>
<div class="h5"><br>
<div style="font-family:times new roman,new
york,times,serif;font-size:12pt">
Joe:<br>
<br>
I agree. I find the comment to be more than
mildly offensive. <br>
<br>
I have the same experience that funky
modeling results usually are the result of
flawed inputs or depending on too many
eQuest defaults.<br>
<div> </div>
Paul Diglio, CEM, CBCP<br>
<br>
<div>87 Fairmont Avenue<br>
New Haven, CT 06513<br>
<a moz-do-not-send="true"
href="tel:203-415-0082"
value="+12034150082" target="_blank">203-415-0082</a></div>
<br>
<br>
<div><span><a moz-do-not-send="true"
rel="nofollow"
href="http://www.pdigliollc.com"
target="_blank">www.pdigliollc.com</a></span>
<div>
<br>
</div>
<div style="font-family:times new
roman,new
york,times,serif;font-size:12pt"><br>
<div style="font-family:times new
roman,new
york,times,serif;font-size:12pt"><font
face="Tahoma">
<hr size="1"><b><span
style="font-weight:bold">From:</span></b>
Joe Huang <<a
moz-do-not-send="true"
href="mailto:yjhuang@whiteboxtechnologies.com"
target="_blank">yjhuang@whiteboxtechnologies.com</a>><br>
<b><span style="font-weight:bold">To:</span></b>
CleanTech Analytics <<a
moz-do-not-send="true"
href="mailto:jeremiah@cleantechanalytics.com"
target="_blank">jeremiah@cleantechanalytics.com</a>><br>
<b><span style="font-weight:bold">Cc:</span></b>
<a moz-do-not-send="true"
href="mailto:equest-users@lists.onebuilding.org"
target="_blank">equest-users@lists.onebuilding.org</a><br>
<b><span style="font-weight:bold">Sent:</span></b>
Sun, July 15, 2012 7:21:54 PM<br>
<b><span style="font-weight:bold">Subject:</span></b>
Re: [Equest-users] Unexpected Custom
SHGC Results<br>
</font><br>
I've found this comment to be mildly
offensive as well as showing a lack of
understanding about how heat gains
ultimately get translated to cooling
energy consumption. It's extremely
hard for me to believe that eQUEST or
DOE-2 has been flawed for 25 years in
modeling something as fundamental as
solar heat gain through windows. In
all the decades I've used DOE-2 to
analyze window performance for DOE's
EnergyStar Program as well as numerous
other projects, whenever the results
did not match or ran counter to
first-principle expectations, it was
always because there was some other
factor that have been overlooked or
ignored, chief among them being the
size of the HVAC system, its
configuration, and control strategy.
Locations with mild cooling loads,
such as San Jose, are particularly
sensitive to such system
interactions. Were both runs done
using "autosizing"? What<br>
kind of a system was modeled - VAV or
CAV ? Did the model have an
economizer? What were the
HEAT-CONTROL and COOL-CONTROL
strategies ? etc. It's far too
early to lay blame on the DOE-2
algorithms.<br>
<br>
Joe<br>
<br>
On 7/14/2012 1:41 PM, CleanTech
Analytics wrote:
<blockquote type="cite"><font
color="#336666"><font
face="verdana,sans-serif">Just
admit it- eQuest is flawed,
you don't have to make up things
to protect it- </font></font>
<div>
<div><font color="#336666"><font
face="verdana,sans-serif"><br>
</font></font></div>
<div><font color="#336666"
face="verdana, sans-serif">If
it is a mistake to use the
percent points rather then
percent reduced from the
abrataty eQuest assumption
from 1999 window specs than
the it should have reduced
solar heat gain by more then
his product even provided-
Using the 33 percentage points
but used the 33% should have
provided him over stated
cooling reduction, (and extra
added heating consumption
tradeoff) </font></div>
<div><font color="#336666"
face="verdana, sans-serif"><br>
</font></div>
<div><span
style="color:rgb(51,102,102);font-family:verdana,sans-serif">O-
and FYI </span>LBL<span
style="color:rgb(51,102,102);font-family:verdana,sans-serif">
window does glass U-value not
shading, ware-as </span>LBL<font
color="#336666" face="verdana,
sans-serif"> optics can be
used for film coefficients and
used to create a custom glass
type in window, but do not do
any calculations for "shading"</font></div>
<div><span
style="color:rgb(51,102,102);font-family:verdana,sans-serif"><br>
</span></div>
<div><font color="#336666"
face="verdana, sans-serif">I
say you try the same model in
Energy Plus or TRNSYS and see
if the results differ.</font></div>
<div><span
style="color:rgb(51,102,102);font-family:verdana,sans-serif"><br>
</span></div>
<div><font color="#336666"><font
face="verdana,sans-serif"><br
clear="all">
</font></font>
<div style="text-align:left"><font
color="#999999"
face="verdana, sans-serif"><i>Jeremiah
D. Crossett</i></font></div>
<div style="text-align:left"><font
color="#999999"
face="verdana, sans-serif"><i>CleanTech
Analytics</i></font></div>
<div style="text-align:left"><font
color="#999999"
face="verdana, sans-serif"><i><a
moz-do-not-send="true"
rel="nofollow">503-688-8951</a></i></font></div>
<div>
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moz-do-not-send="true"
rel="nofollow"
href="http://www.cleantechanalytics.com"
target="_blank"><font
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face="verdana,
sans-serif"><i>www.cleantechanalytics.com</i></font></a></div>
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style="text-align:center">
<br>
</div>
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style="text-align:center"><img
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</div>
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<div><b>
<p dir="ltr"
style="text-align:center;margin-top:0pt;margin-bottom:0pt">
<span>This document may
contain valuable
information
proprietary to
CleanTech Analytics
which is private and
confidential. It may
not be shared, copied,
stored or transmitted
in any form without
the prior written
consent of CleanTech
Analytics</span></p>
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<br>
<br>
<br>
<div class="gmail_quote">On Sat,
Jul 14, 2012 at 12:42 PM, Liam
O'Brien <span dir="ltr"><<a
moz-do-not-send="true"
rel="nofollow"
href="mailto:obrien_liam@hotmail.com"
target="_blank">obrien_liam@hotmail.com</a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0 0 0
.8ex;border-left:1px #ccc
solid;padding-left:1ex">
<div>
<div dir="ltr"> Hi Pete,
<div><br>
</div>
<div>I don't have a ton
of experience with
detailed modelling of
shades in eQUEST,
specifically, but two
things that could be
at play:</div>
<div><br>
</div>
<div>- The claim from
the manufacturer
sounds like it's not
intended to universal
in absolute terms.
Also, it would be more
conservative to reduce
the SHGC by 3<span
style="font-size:10pt">3
percent than 33</span><span
style="font-size:10pt"> </span><u style="font-size:10pt">percentage
points</u><span
style="font-size:10pt">
(as you did)</span><span
style="font-size:10pt"> if you're going to take this simplified
approach. Therefore,
it would be closer
to SHGC=0.44. Subtle
but significant. You
could try using
software that
specializes in
window/shade
performance like
LBNL Window or
Parasol to try to
characterize the
performance of your
specific
shade-glazing
combination</span></div>
<div>- Depending on the
operating conditions
and construction of
the building, there's
a chance your results
aren't ridiculous. If
shades intercept
transmitted solar
radiation, then a lot
of that energy will
almost immediately
transfer to the air
via convection. If you
have thermally massive
interior surfaces,
there's a chance your
building could
actually perform
better without those
shades because the air
conditioning won't
kick in till later. </div>
<div><br>
</div>
<div>Liam</div>
<div><br>
<div>
<hr>Date: Sat, 14
Jul 2012 11:51:02
-0700<br>
From: <a
moz-do-not-send="true"
rel="nofollow"
href="mailto:pbaumstark@sbcglobal.net"
target="_blank">pbaumstark@sbcglobal.net</a><br>
To: <a
moz-do-not-send="true"
rel="nofollow"
href="mailto:equest-users@lists.onebuilding.org"
target="_blank">equest-users@lists.onebuilding.org</a><br>
Subject:
[Equest-users]
Unexpected Custom
SHGC Results
<div>
<div><br>
<br>
<div
style="font-family:arial,helvetica,sans-serif;font-size:12pt">
<div>Hello,<br>
<br>
I have an "L"
shaped
building with
the point of
the "L" facing
North. The
inside of the
"L" has both
NE and NW
surfaces, that
include a high
amount of
glass, which
heats up the
perimeter
building
spaces
considerably
during the
summer.
Glazing is
single pane
tinted.<br>
<br>
The customer
wants to
install some
Verisol
SilverScreen
shades in
these
windows.
According to
the
manufacturer,
the SHGC will
reduce by
about 33%. I
modeled in
eQUEST, window
properties in
these windows
to have an
SHGC of 0.67
and ran an EEM
reducing SHGC
to 0.34, and
got an
increase in
cooling load
and fan load
year round,
even in the
summer months.<br>
<br>
Am I seeing
this wrong? I
can't figure
out how I
could possible
get results
like this?<br>
<br>
Thank you,<br>
Pete<br>
San Jose, CA<br>
</div>
</div>
<br>
</div>
</div>
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<br>
<br>
<div>-- <br>
Joe Huang White Box Technologies,
Inc. 346 Rheem Blvd., Suite 108D
Moraga, CA 94556 (o) <a
moz-do-not-send="true"
href="tel:%28925%29388-0265"
value="+19253880265"
target="_blank">(925)388-0265</a>
(c) <a moz-do-not-send="true"
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value="+15109282683"
target="_blank">(510)928-2683</a>
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rel="nofollow"
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target="_blank">www.whiteboxtechnologies.com</a>
"Building energy simulations at your
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</div>
</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<br>
<br>
<div class="moz-signature">-- <br>
Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 108D
Moraga, CA 94556
(o) (925)388-0265
(c) (510)928-2683
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