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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>All;<o:p></o:p></span></font>
</p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I should have known this already, but <st1:PersonName
w:st="on">Jeff Hirsch</st1:PersonName> clarified that DOE-2 users may need to adjust
(carefully) the relative COOLING/HEATING-DESIGN-Ts in buffer zones if
auto-sizing airflows. I USUALLY find the default minimum design airflows and
safety factors result in adequate airflows in the conditioned zones. However:<o:p></o:p></span></font>
</p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font>
</p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>--- <br>
<st1:PersonName w:st="on">Jeff Hirsch</st1:PersonName> responded:<o:p></o:p></span></font>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Relative to the dT used for the interior wall heat transfer
...</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The <strong><b><font face=Arial><span style='font-family:
Arial'>hourly</span></font></b></strong> simulated heat transfer across an
interior wall is based on the <strong><b><font face=Arial><span
style='font-family:Arial'>hourly</span></font></b></strong></span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>simulated temperatures on either side of the wall. The
<strong><b><font face=Arial><span style='font-family:Arial'>design</span></font></b></strong>
calculation heat transfer</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>across an interior wall is governed ONLY be the <strong><b><font
face=Arial><span style='font-family:Arial'>design</span></font></b></strong>
temperatures of the zones on</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>either side of the wall.</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The "adjust loads" feature controls if the peak
load arising from the hourly fixed temperature</span></font><o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>load calculation for each SPACE</span></font> <font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'>is
"adjusted" during the HVAC sizing calculation based</span></font><o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>upon the specified heat/cool design temperatures for the
ZONE that</span></font> <font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>represents that SPACE</span></font><o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>for the HVAC simulation.</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The unconditioned and plenum design temperatures can start
as a "guess" and then be</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>adjusted based upon simulation values. There is no
automated "capture" of design day</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>unconditioned/plenum zone temperatures at the time of each
connected conditioned</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>zone peak load to feed into the calculation. This is
not unique to DOE-2/eQUEST, but</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>we are adding a better method to handle this and other
sizing issues automatically in</span></font> <o:p></o:p>
</p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>the next version of DOE-2 (expected next year)</span></font>
<o:p></o:p>
</p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> <o:p></o:p></span></font>
</p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>From JJH's response above, if the design
temperatures are the same for a "plenum" and the space below, there
will be no heat transfer during the sizing calculation; that's why changing "plenum"
roof characteristics did not change design airflow in the conditioned space
below the ceiling.<o:p></o:p></span></font>
</p>
<div>
<p class=MsoNormal><font size=2 color=navy face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:navy'>--</span></font><font
color=navy><span style='color:navy'><o:p></o:p></span></font>
</p>
<p class=MsoNormal><font size=2 color=navy face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:navy'>Fred </span></font><o:p></o:p>
</p>
</div>
<div>
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face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Fred Porter <br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, July 17, 2007 9:29
AM<br>
<b><span style='font-weight:bold'>To:</span></b> BLDG-SIM@gard.com<br>
<b><span style='font-weight:bold'>Subject:</span></b> [BLDG-SIM] What does
ADJUST-LOADS adjust?</span></font><o:p></o:p>
</p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font>
</p>
<p style='margin-bottom:12.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>All;<br>
When simulating (eQ v3-61, DOE-2.2 v44e4) a building with a "plenum"
(unconditioned or plenum), and changing the roof absorptance greatly, the
auto-sized design air flow does NOT seem to change in the zone below, even
though the ZONE SIZING-OPTION = ADJUST-LOADS. After observing this in a big
model, I tested this in a simple single zone model (eQ Wiz). I made sure
airflow sizing was driven by cooling loads, and created a parametric run that
changed the ABSORPTANCE of the roof construction between 90% and 10%. Hourly
cooling loads vary as expected, but design airflow remains the same between
both models. <o:p></o:p></span></font>
</p>
<p style='margin-bottom:12.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Raising the DESIGN-COOL-T (from the default 75F, same
for all zones) in the "plenum" increases the design airflow in the
zone below (for both absorptances), but I thought ADJUST-LOADS did more than
just recognize this input. The problem seems to persist whether I have a
cooling design day or not, and whatever I do with the LOADS SPACE
"TEMPERATUREs" and ZONE DESIGN-COOL-Ts. <br>
<br>
Any insights out there? Anyone else notice this behavior? Is this a bug, or did
I expect too much of the program? Unless the DESIGN-COOL-T is raised (to a
value one must estimate or find by inspection of hourly reports), it appears
the program under-sizes airflow to zones where a significant fraction of the
heat gain is through a ceiling cavity/plenum/attic, or I suppose any
"un-conditioned" buffer space.<br>
<br>
Fred Porter <o:p></o:p></span></font>
</p>
<pre><font size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font>
</pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'><o:p> </o:p></span></font>
</pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>>orterace.<br>
<br>
<o:p></o:p></span></font>
</pre><pre><font size=2 face="Courier New"><span
style='font-size:10.0pt'><o:p> </o:p></span></font>
</pre><pre><font
size=2 face="Courier New"><span style='font-size:10.0pt'>c, or I sYou received this e-mail because you are subscribed<o:p></o:p></span></font>
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