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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Adam, <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'>Potential issues with how you model the variable flow…<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'>For sure, there is a problem with supply air temperature for
heating. The following is from the Help File:<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'>“</span>Use of HEAT-SET-T for systems SZRH and PSZ is
discouraged because it simply overrides the maximum leaving air temperature
specified by MAX-SUPPLY-T”.<o:p></o:p></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’ve set your MAX-SUPPLY-T at 110 F and your HEAT-SET-T
at 80 F. You are heating with only 80 F.<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'>Demba NDIAYE<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><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"'>
bldg-sim-bounces@lists.onebuilding.org
[mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Adam
Gonthier<br>
<b>Sent:</b> Thursday, July 29, 2010 4:22 PM<br>
<b>To:</b> equest-users@lists.onebuilding.org; bldg-sim@lists.onebuilding.org;
Vidya Gowda<br>
<b>Subject:</b> [Bldg-sim] PSZ Very High Unmet Hours<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Dear eQuest users, <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I am having some difficulty with a project I am working on,
and I was hoping I could receive some help or any information on a building a
with packaged single zone units with DX cooling and hot water coils for
heating, with a VFD to vary the supply flow (there are no VAV boxes in the
system, and the supply reacts to overall building pressure rather than specific
zonal needs determined by pressure sensors in the ductwork). There
is no reheat in the system either. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>It is a LEED for schools project where the simulation of the
proposed model shows very high unmet loads for heating and the total energy
consumption for space heating is 199 MBTU which is unrealistically low as
compared to the baseline model space heating which is 6369 MBTU. We do
not see many unmet hours in the control zone, but since the unit supplies many
zones, we are getting very high unmet heating hours in non-control zone
spaces. We are seeing on the order of 4000-5000 hours unmet in many zones.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I have modeled the heating for all zones by specifying the <o:p></o:p></p>
<p class=MsoNormal><b>Heat Source</b> as hot water loop, <o:p></o:p></p>
<p class=MsoNormal><b>The Zone Heat Source</b> is not installed, as the design
has no reheat. <o:p></o:p></p>
<p class=MsoNormal><b>Zone</b> <b>entering maximum supply temperature</b> is at
110 degrees. <o:p></o:p></p>
<p class=MsoNormal><b>Hot</b> <b>deck max leaving temp</b> is 80 degrees<o:p></o:p></p>
<p class=MsoNormal><b>Reheat delta T</b>: n/a<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Many thanks in advance, <o:p></o:p></p>
<p class=MsoNormal><b><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#009E49'>Adam A. Gonthier</span></b><o:p></o:p></p>
<p class=MsoNormal><em><b><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#009E49'>Energy Engineer</span></b></em><b><i><span style='font-size:
9.0pt;font-family:"Arial","sans-serif";color:#009E49'><br>
</span></i></b><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#827F78'>Horizon Engineering Associates, LLP</span><span
style='font-size:10.0pt'><ns0:PostalCode><span style='font-size:9.0pt;
font-family:"Arial","sans-serif";color:#009E49'><br>
</span></ns0:PostalCode></span><span lang=FR style='font-size:9.0pt;
font-family:"Arial","sans-serif";color:#827F78'>347.297.9005</span><o:p></o:p></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:green'><a href="http://www.horizon-engineering.com/"
title="http://www.horizon-engineering.com/"><span lang=FR style='font-size:
9.0pt;color:#009E49'>www.horizon-engineering.com</span></a></span><span
style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#009E49'><br>
<br>
<b><i>Demand a Higher Standard</i><br>
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style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#009E49'> </span><span
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