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<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial">I am modeling a building with an existing single zone 4-pipe chilled and hot water air handler unit that is currently constant volume but being converted to
constant volume. The unit feeds many spaces through a single duct. I modeled the system as a single zone with heat (SZRH) system and tried to add in a variable speed drive and lower the minimum flow ratio, but can’t get the fan speed to reduce when not needing
100% flow. I also tried modeling the system as a variable volume system (VAVS) and the airflow ramps down but then the program adds a VAV box for each zone, which isn’t what is occurring. I am trying to control only to the worst case zone, as will be the
installed case. <o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial">Which system type should I be using for modeling this system, and how do I get it to model as noted above?<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial">I appreciate any help! Thanks,<o:p></o:p></span></font></p>
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font-family:Arial"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><st1:PersonName w:st="on"><strong><b><font size="3" color="#585858" face="GoudyOlSt BT"><span style="font-size:12.0pt;font-family:
"GoudyOlSt BT";color:#585858">Matt Larson</span></font></b></strong></st1:PersonName><font size="2" color="#585858" face="GoudyOlSt BT"><span style="font-size:10.0pt;
font-family:"GoudyOlSt BT";color:#585858">,
P.E., QCxP, LEED AP</span></font><o:p></o:p></p>
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12.0pt"><o:p> </o:p></span></font></p>
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