I owe you all an apology. I sent an email to Vikram using the reply vs reply-all button telling him that I thought his problem might be in specifying the curve as linear. He changed it to quadratic and got much more reasonable results.<br>
Carol<br><br><div class="gmail_quote">On Fri, Mar 5, 2010 at 3:34 PM, Bill <span dir="ltr"><<a href="mailto:bkoran@qwest.net">bkoran@qwest.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div link="blue" vlink="purple" lang="EN-US">
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>Steven, Vikram, et. al., </span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>Reid communictated with me in developing that
presentation, since I authored the spreadsheet tool. As the author of the
tool, I will vouch for the analytical approach, and the tool was peer reviewed
since it was funded by the California Commissioning
Collaborative.</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>As for tool useability, well, it is pretty useable but
not where I would like it to be. The tool (and others) is available
at:</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span><a href="http://www.cacx.org/resources/rcxtools/spreadsheet_tools.html" target="_blank">http://www.cacx.org/resources/rcxtools/spreadsheet_tools.html</a></span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>It was developed in Excel 2003; I am uncertain whether
there are any issues with other versions.</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>Yes, I believe the default DOE-2/eQuest VAV curves are
quite optimistic. Even the tool that comes out of my spreadsheet tool is
likely somewhat optimistic, even though it attempts to include fan, VFD, and
motor efficiencies at the various operating points. Pressure drops
relative to flow could be slightly better modeled for the portion of the system
with filters and coils, and that would further increase off-design
power.</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>How well a particular curve fits a particular system is
most significantly a function of </span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>(1) whether and how the static pressure setpoint (to
which the VFD controls the fan speed) is reset.</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>(2) if the static pressure setpoint is not reset, where
the sensor is in the duct system, and how high the setpoint is relative to the
fan pressure rise.</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>This figure is related to what Reid showed in his
presentation, and relates some of these issues.</span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font><font color="#0000ff" face="Arial" size="2"><span><font color="#0000ff" face="Arial" size="2"><span></span></font> </span></font></div>
<div dir="ltr" align="left">
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span>--Bill</span></font></div></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span><img src="" alt="" align="baseline" border="0" hspace="0"></span></font></div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span></span></font><font color="#0000ff" face="Arial" size="2"><span></span></font> </div>
<div dir="ltr" align="left"><font color="#0000ff" face="Arial" size="2"><span><font color="#000000" face="Tahoma">William E. Koran,
P.E.<font face="Times New Roman" size="3"> </font><br>Senior Engineer</font><font size="3"><font color="#000000"><font face="Times New Roman"> <br></font><font face="Tahoma">Q u E S T</font></font><font color="#000000" face="Times New Roman">
<br></font></font><font color="#000000" face="Tahoma" size="1">Quantum Energy Services
and Technologies</font><font color="#000000"><font face="Times New Roman" size="3">
<br></font><font face="Tahoma" size="2">3945 Parker Road</font></font><font color="#000000"><font face="Times New Roman" size="3"> <br></font><font face="Tahoma" size="2">West Linn, OR 97068</font></font><font color="#000000"><font face="Times New Roman" size="3"> <br>
</font><font face="Tahoma" size="2">Voice:
503-557-7828</font></font><font color="#000000"><font face="Times New Roman" size="3"> <br></font><font face="Tahoma" size="2">Fax:
510-540-7268</font></font><font color="#000000"><font face="Times New Roman" size="3"> <br></font><font face="Tahoma" size="2">Web:</font><font face="Times New Roman" size="3"> </font></font><a title="blocked::http://www.quest-world.com/"><u title="blocked::http://www.quest-world.com/"></u><u title="blocked::http://www.quest-world.com/"><font title="blocked::http://www.quest-world.com/" color="#0000ff" face="Tahoma" size="2">www.quest-world.com</font></u></a></span></font></div>
<br>
<div dir="ltr" align="left" lang="en-us">
<hr>
<font face="Tahoma" size="2"><b>From:</b> <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Steven
Savich<br><b>Sent:</b> Friday, March 05, 2010 3:03 PM<br><b>To:</b> 'Vikram
Sami'; 'eQUEST Users List'<br><b>Subject:</b> Re: [Equest-users] More about
fans<br></font><br></div><div><div></div><div class="h5">
<div></div>
<div>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">Vikram,</span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">Reid Hart of PECI did a
presentation on this issue for the building simulation user's group a few months
ago, and discussed a spreadsheet tool to construct accurate DOE2 performance
curves for variable flow air and water systems. I believe the powerpoint
presentation is still archived on the BSUG yahoo site, and the spreadsheet is
downloadable from PECI's website. I haven't tried using this tool yet, so
I cannot vouch for its accuracy or useability.</span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"> </span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);">Steven</span></p>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"> </span></p>
<div>
<p class="MsoNormal"><span style="font-family: 'Bookman Old Style','serif'; color: rgb(31, 73, 125);">Steven Savich,
LEED AP</span><span style="font-family: 'Times New Roman','serif'; color: rgb(31, 73, 125); font-size: 12pt;"></span></p>
<p class="MsoNormal"><span style="font-family: 'Bookman Old Style','serif'; color: rgb(31, 73, 125); font-size: 10pt;">Systems
West Engineers</span><span style="color: rgb(31, 73, 125);"></span></p>
<p class="MsoNormal"><span style="font-family: 'Bookman Old Style','serif'; color: rgb(31, 73, 125); font-size: 10pt;">411
High Street</span><span style="color: rgb(31, 73, 125);"></span></p>
<p class="MsoNormal"><span style="font-family: 'Bookman Old Style','serif'; color: rgb(31, 73, 125); font-size: 10pt;">Eugene,
OR 97401-2427</span><span style="color: rgb(31, 73, 125);"></span></p>
<p class="MsoNormal"><span style="font-family: 'Bookman Old Style','serif'; color: rgb(31, 73, 125); font-size: 10pt;">(541)
342-7210</span><span style="color: rgb(31, 73, 125);"></span></p>
<p class="MsoNormal"><span style="font-family: 'Bookman Old Style','serif'; color: rgb(31, 73, 125); font-size: 10pt;">(541)
342-7220 (fax)</span><span style="color: rgb(31, 73, 125);"></span></p></div>
<p class="MsoNormal"><span style="color: rgb(31, 73, 125);"> </span></p>
<div>
<div style="border-style: solid none none; border-color: rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color; border-width: 1pt medium medium; padding: 3pt 0in 0in;">
<p class="MsoNormal"><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;">
<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Vikram
Sami<br><b>Sent:</b> Friday, March 05, 2010 2:01 PM<br><b>To:</b> eQUEST Users
List<br><b>Subject:</b> [Equest-users] More about
fans</span></p></div></div>
<p class="MsoNormal"> </p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);">Same model – different fan
question. Table G3.1.3.15 Gives you a part load performance table for VAV fan
systems. Based on that, I created a performance curve (linear) for my VAV fan
system that looks like this:</span></p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);"> </span></p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);"><img src="" width="734" height="546"></span></p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);"> </span></p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);"> </span></p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);">Problem is when I use this as
opposed to the default curve that came out of the wizard, the fan energy
doubles. The fan energy is still only 8% of the overall building load, so its
not alarming. Does this mean that the default curve was way to low? Is the
method above the way to model this performance curve?</span></p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);"> </span></p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);">Thanks for your
help</span></p>
<p class="MsoNormal"><span style="color: rgb(0, 0, 180);"> </span></p>
<div>
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