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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Sorry, I should have explained further. I am trying to simulate a sequence of measures, one of which is adding variable speed control to the ahu fan for the dual duct system. That is the measure with the problem. A dual fan dual duct system with VAV control on the system fans works fine and the SS-L report shows the fan power varying while the single duct system won’t vary unless I take the 100% OA requirement out and add occupancy OA control at the zone level. Why can’t I make a single fan dual duct system have a VFD on the main ahu fan?<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'>Bryce<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><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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"'> John Aulbach [mailto:jra_sac@yahoo.com] <br><b>Sent:</b> Tuesday, February 01, 2011 10:58 AM<br><b>To:</b> Bryce Munger; equest-users@lists.onebuilding.org<br><b>Subject:</b> Re: [Equest-users] Dual Duct VAV problems<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>Bryce:<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>Forgive my systems ignorance. But if you have a single fan dual duct system, don't the hot and cold deck dampers just swing from heating to cooling? How will the airflow vary unless you have two fans?<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal>I can learn as well from our well versed members.<o:p></o:p></p></div><div><p class=MsoNormal> <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>John R. Aulbach, PE, CEM<o:p></o:p></span></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>Senior Energy Engineer<o:p></o:p></span></p><div><div class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#17365D'><hr size=2 width="30%" noshade style='color:#17365D' align=left></span></div></div><p class=MsoNormal><b><span style='font-family:"Calibri","sans-serif";font-variant:small-caps;color:navy'>Partner</span></b><b><span style='font-family:"Calibri","sans-serif";font-variant:small-caps;color:green'> </span></b><b><span style='font-family:"Calibri","sans-serif";font-variant:small-caps;color:#006600'>Energy</span></b><b><span style='font-family:"Calibri","sans-serif";font-variant:small-caps;color:navy'><o:p></o:p></span></b></p><p class=MsoNormal><span style='font-family:"Calibri","sans-serif";color:#1F497D'>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><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";color:#1F497D'> </span><a href="mailto:%7C%20jaulbach@ptrenergy.com"><span style='font-family:"Calibri","sans-serif"'>| jaulbach@ptrenergy.com</span></a><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p><div><div class=MsoNormal align=center style='text-align:center'><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><hr size=1 width="100%" align=center></span></div><p class=MsoNormal style='margin-bottom:12.0pt'><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"'> Bryce Munger <BMunger@glumac.com><br><b>To:</b> equest-users@lists.onebuilding.org<br><b>Sent:</b> Tue, February 1, 2011 10:46:02 AM<br><b>Subject:</b> [Equest-users] Dual Duct VAV problems</span><o:p></o:p></p><div><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif"'>I am working on a dual duct simulation and I am having trouble getting vav control to work correctly. The system is defined as a 100% OA Dual Duct Single Fan system and I have tried everything I can think of to get the fans to vary. When the sim runs, the fans are pegged in the 90-100% range all year. When I change to a dual fan dual duct system, the fans will act as a vav fan is expected with a range of operating hours throughout the year. I have tried Fan Control of “Variable Speed” and “Fan EIR FPLR” without success. Any ideas?</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif"'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif"'>Thanks, </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif"'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif"'>Bryce</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif"'> </span><o:p></o:p></p></div></div></div></div></div><p class=MsoNormal><o:p> </o:p></p></div></body></html>