<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>I didn't make any changes to the return fan system when switching between 0.81 and 1.0. Both have a return fan, sized similarly. Although this is not entirely accurate, that's what I have at the moment.</span></div><div><br></div> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div dir="ltr"> <font size="2" face="Arial"> <div style="margin: 5px 0px; padding: 0px; border: 1px solid rgb(204, 204, 204); height: 0px; line-height: 0; font-size: 0px;" class="hr" contentEditable="false" readonly="true"></div> <b><span style="font-weight: bold;">From:</span></b> "Busman, Michael R" <MBusman@chevron.com><br> <b><span style="font-weight: bold;">To:</span></b> Maria Ramos
<mramos@innovaengineers.com>; "equest-users@lists.onebuilding.org" <equest-users@lists.onebuilding.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Monday, September 24, 2012 3:44 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> RE: [Equest-users] 100% outdoor air system<br> </font> </div> <br>
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<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;">Maria,</span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;"> </span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;">Do you now have a return air fan specified where you had no exhaust fan previously, or return fan kW that is greater than a previous exhaust fan? If so, that
could explain your fan energy increase and cooling energy increase as well due to fan heat and maybe some duct heat gain.</span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;"> </span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;">Sorry, but that’s all I can think of without knowing more specifics.</span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;"> </span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;">My best,</span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;"> </span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;">Mike Busman</span></div>
<div class="yiv1113115746MsoNormal"><span style="color: rgb(31, 73, 125); font-size: 11pt;"> </span></div>
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<div class="yiv1113115746MsoNormal"><b><span style="font-size: 10pt;">From:</span></b><span style="font-size: 10pt;"> equest-users-bounces@lists.onebuilding.org [mailto:equest-users-bounces@lists.onebuilding.org]
<b>On Behalf Of </b>Maria Ramos<br>
<b>Sent:</b> Monday, September 24, 2012 11:44 AM<br>
<b>To:</b> equest-users@lists.onebuilding.org<br>
<b>Subject:</b> [Equest-users] 100% outdoor air system</span></div>
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<div style="background: white;" class="yiv1113115746MsoNormal"><span style="color: black;">All, I am modeling a large research tower, 470,000 SF. On past projects, all of the HVAC systems were 100% outdoor air with heat pipe energy recovery. On this project, we will be returning
part of the building, yielding 81% outdoor air. I am trying to model the energy savings. Equest is actually showing an increase in utility costs for going from 100% to 81%, both with and without energy recovery, which is the opposite of what I expected.
Both versions of the baseline have economizer. If I compare the utility consumption, it looks as if the fan energy has increased significantly by decreasing the amount of outdoor air (entered as a fraction on the system outdoor air tab) and the cooling energy
has increased a little.</span></div>
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<div style="background: white;" class="yiv1113115746MsoNormal"><span style="color: black;"> </span></div>
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<div style="background: white;" class="yiv1113115746MsoNormal"><span style="color: black;">Does anyone have any idea what combination of inputs that I have that would lead to this problem? It seems to me that these results couln't be valid.</span></div>
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<div style="background: white;" class="yiv1113115746MsoNormal"><span style="color: black;"> </span></div>
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<div style="background: white;" class="yiv1113115746MsoNormal"><span style="color: black;">Thanks,</span></div>
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<div style="background: white;" class="yiv1113115746MsoNormal"><span style="color: black;">Maria Ramos, PE</span></div>
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