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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>John,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Internal gains figure into Ben 's approach by choosing a HDD
number based on a balance point temperature that is below the actual space set
point.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>The balance point temperature is a theoretical temperature at which
the building does not require heating because the internal gains offset the
envelope loads.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>To say it accounts for solar gain is a stretch but hey it is
just a hand calc. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Ben does not state which HDD base he chose, but there are published
values for temps like 55F, 60F, 65F etc. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Ben,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>It is good you are checking your results but I would ask do you believe
your baseline model? Try your HDD calc on the your building U rather than
the differential. How does that gas consumption compare to your baseline
model heating gas consumption?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Does a different HDD base fit your model better?<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>If you think your baseline model is okay, when you changed the U
did you also change your shading coefficient? A lower SC would
eliminate some passive solar heating.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>A daylighting interaction could be another possibility.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>You'll figure it out.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Paul Riemer<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Dunham<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> equest-users-bounces@lists.onebuilding.org
[mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>John
Aulbach<br>
<b>Sent:</b> Wednesday, August 25, 2010 3:38 PM<br>
<b>To:</b> Ben Pressman; equest-users@lists.onebuilding.org<br>
<b>Subject:</b> Re: [Equest-users] BEPU space heating calculation<o:p></o:p></span></p>
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<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
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<p class=MsoNormal style='margin-left:.5in'>Ben - dumb question.<o:p></o:p></p>
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<p class=MsoNormal style='margin-left:.5in'> <o:p></o:p></p>
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<p class=MsoNormal style='margin-left:.5in'>How is internal load figuring into
this equation? And solar gain from the sun?<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal style='margin-left:.5in'> <o:p></o:p></p>
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<div>
<p class=MsoNormal style='margin-left:.5in'>I NEVER get an exact U x A x dT
savings, as eQuest takes ALL factors into consideration.<o:p></o:p></p>
</div>
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<p class=MsoNormal style='margin-left:.5in'> <o:p></o:p></p>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:.5in'><span style='font-family:"Calibri","sans-serif"'>John R.
Aulbach, PE, CEM<o:p></o:p></span></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:.5in'><span style='font-family:"Calibri","sans-serif"'>Senior
Energy Engineer<o:p></o:p></span></p>
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<hr size=2 width="30%" noshade style='color:#ACA899' align=left>
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<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:.5in'><b><span style='font-family:"Calibri","sans-serif"'>Partner
Energy<o:p></o:p></span></b></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:.5in'><span style='font-family:"Calibri","sans-serif"'>1990 E.
Grand Avenue, El Segundo, CA 90245<br>
W: 888-826-1216, X254| D: 310-765-7295 | F: 310-817-2745<o:p></o:p></span></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:.5in'><a href="http://www.ptrenergy.com/"><span style='font-family:
"Calibri","sans-serif"'>www.ptrenergy.com</span></a><span style='font-family:
"Calibri","sans-serif"'> </span><a href="mailto:%7C%20jaulbach@ptrenergy.com"><span
style='font-family:"Calibri","sans-serif"'>| jaulbach@ptrenergy.com</span></a><o:p></o:p></p>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
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<div>
<p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p>
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<div class=MsoNormal align=center style='margin-left:.5in;text-align:center'><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
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<p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> Ben Pressman <bpressman@practicalenergy.net><br>
<b>To:</b> equest-users@lists.onebuilding.org<br>
<b>Sent:</b> Wed, August 25, 2010 1:32:04 PM<br>
<b>Subject:</b> [Equest-users] BEPU space heating calculation<br>
</span><br>
I have a Window Glass EEM run that upgrades the windows in a 1970s school
building from single-paned to double-paned, tinted, and argon-filled; a
decrease in U-factor from 1.04 to 0.35. The LV-D report shows a decrease in
building U-factor from 0.176 to 0.142 which, based on an HDD calculation:<br>
<br>
(0.176-0.142)*24hrs*(estimated HDD for my area)*A/eff = 1217 therms<br>
<br>
of savings, or 24.7% of the overall energy usage of my baseline model. The BEPU
report, however, shows almost no energy savings. How can this be? Is there some
way to see what schedule, or number of degree days the calculation in the BEPU
is using? Has anyone had this sort of problem?<br>
<br>
Thanks,<br>
Ben<br>
<br>
-- Ben Pressman<br>
Project Engineer<br>
Practical Energy Solutions<br>
770 E. Market Street, Suite 250<br>
West Chester, PA 19382<br>
ph 610.430.1382<br>
cell 610.733.9518<br>
web <a href="http://www.practicalenergy.net/">www.practicalenergy.net</a><br>
<br>
<br>
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