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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='color:#1F497D'>Hi David,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I’ve been looking for a solution to this for a while. Modeling a DOAS using the dummy zone (set all walls to adiabatic, or with a u-value of 0.00001) is one thing, and can be done pretty easily. All your zones can get their OA from that zone. There’s plenty of posts in the <a href="http://lists.onebuilding.org/pipermail/equest-users-onebuilding.org/">archive</a> for this (search for dummy zones), so I’ll leave it there.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>The trouble is, unless I’m missing something, you can’t route the exhaust air back to the DOAS, so your ERV won’t model correctly. I’ve resorted to creating an hourly report and calculating the additional ERV savings, minus additional fan and motor losses. It’s certainly not ideal, and I haven’t tried it on a LEED project yet, so I can’t speak to the acceptability to the USGBC.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I had taken an eQuest training class, maybe 1.5 years ago, and the instructor had mentioned the developers were currently working on developing a DOAS system for eQuest and they hoped to release it within a few months, but nothing yet. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>If anyone has found a way to get this working properly, or has any updates on the development in eQuest (is it in the forthcoming 3.64?), that would be great to know. It’s frustrating, because it is certainly only going to be more prevalent in the future.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Eric<o:p></o:p></span></p><p class=MsoNormal><span style='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 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>David Everhart<br><b>Sent:</b> Wednesday, February 24, 2010 10:14 AM<br><b>To:</b> equest-users@lists.onebuilding.org<br><b>Subject:</b> [Equest-users] Dedicated Outside Air Unit<o:p></o:p></span></p></div></div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'>I have a school which will be served by ground source heat pumps. Outside air will be provided to the classrooms with a Dedicated Outside Air Unit/ ERV with a VAV fan which operates based on CO2 sensors within the spaces. The heat pumps won’t have any outside air provided to them.<o:p></o:p></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'>My question is what’s the best way to model this? Since you can’t apply more than one HVAC system to a particular space, do I create a fake space and apply the outside air unit/ERV to that? If so, how do I model the fake space such that there is no heat loss and only people to require outside air?<o:p></o:p></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'>I tried to just model the dedicated outside air system by way of the heat pumps, but I run into problems when trying to specify when the dedicated outside air unit would operate. I would want it to operate independently from just when the heat pump is operating and I can’t find a way to do this.<o:p></o:p></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'>Has anyone had any luck modeling something similar to this?<o:p></o:p></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'>Thanks.<o:p></o:p></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:10.0pt;font-family:"Gill Sans MT","sans-serif";color:#0070C0'>David B. Everhart, P.E. LEED AP<o:p></o:p></span></b></p><p class=MsoNormal style='margin-left:.5in'><b><i><span style='font-size:10.0pt;font-family:"Gill Sans MT","sans-serif";color:#0070C0'>Latimer, Sommers and Associates, P.A</span></i></b><i><span style='font-size:10.0pt;font-family:"Gill Sans MT","sans-serif";color:#0070C0'>.<o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Gill Sans MT","sans-serif";color:#595959'>3639 SW Summerfield Dr., Suite A<o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Gill Sans MT","sans-serif";color:#595959'>Topeka, KS 66614<o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Gill Sans MT","sans-serif";color:#595959'>p. 785.233.3232<o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Gill Sans MT","sans-serif";color:#595959'>f. 785.233.0647<o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><i><span style='font-size:10.0pt;font-family:"Gill Sans MT","sans-serif";color:#595959'><a href="mailto:deverhart@lsapa.com">deverhart@lsapa.com</a><o:p></o:p></span></i></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p></div></body></html>