<html><head></head><body><div class="ydp10066c5byahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div><div dir="ltr" data-setdir="false">Hi David:</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">No heat exchangers in the .inp file.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Thank you,</div><div><br></div><div class="ydp10066c5bsignature">Paul Diglio<br>87 Fairmont Avenue <br>New Haven, CT  06513 <br><br>203-415-0082</div></div>
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                    On Tuesday, December 10, 2019, 10:46:12 AM EST, David Eldridge <deldridge@grummanbutkus.com> wrote:
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I didn’t think of this earlier, but search the *.inp to see if one is in there associated with the AHU that crashes, maybe some relic code is in the file that isn’t shown in the UI.<br clear="none">
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<div dir="ltr">DSE Mobile
<div>773.490.5038</div>
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<blockquote type="cite">On Dec 10, 2019, at 9:30 AM, Paul Diglio via Equest-users <equest-users@lists.onebuilding.org> wrote:<br clear="none">
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<div dir="ltr">Hi Sharad:</div>
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<div dir="ltr">I can't find any heat exchangers in my model.  How did you pull up the heat exchanger screen?</div>
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<div dir="ltr">Thank you,<br clear="none">
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<div class="ydp958c632yiv2153677201ydp9b35a8d3signature">Paul Diglio<br clear="none">
87 Fairmont Avenue <br clear="none">
New Haven, CT 06513 <br clear="none">
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<div>On Tuesday, December 10, 2019, 9:29:01 AM EST, Sharad Kumar via Equest-users <equest-users@lists.onebuilding.org> wrote:
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<div><font color="#073763">Hi Paul,</font></div>
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<div><span style="color:rgb(7,55,99);">I think the problem is being caused due to some heat exchanger kind of thing being modeled in the built.</span><br clear="none">
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<div><font color="#073763">I am guessing out the problem as follows:</font></div>
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<div><font color="#073763">The UA calculations does not converge as there can be might possibility that then UA product and after multiplication with delta T does not converge with the meeting of the capacity as the formula is Q= U* A* delta T.</font></div>
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<div><font color="#073763">Q=  Capacity</font></div>
<div><font color="#073763">UA= product of conductance and cross sectional area.</font></div>
<div><font color="#073763">delta T= Temperature difference between ends.</font></div>
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<div><font color="#073763">Hence try to succumb with the problem in lieu-wise as above.</font></div>
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<div><font color="#073763">The other factors to have the UA product calculations to be right are as in above help page super-script which might can also guide as there are other factors based calculations is there as if there the boxed figure are outrun.</font></div>
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<div><font color="#073763">Hope this might help.</font></div>
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<div><b><font color="#073763">Thanks and regards,</font></b></div>
<div><font color="#073763">Sharad.Kumar</font></div>
<div><font color="#073763">Freelancer-Energy Simulation and Day-lighting.</font></div>
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<div dir="ltr"><b><font color="#20124d">....................................................................................................................................................</font></b>.</div>
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<div dir="ltr">---------- Forwarded message ----------<br clear="none">
From: Paul Diglio <<a shape="rect" href="mailto:paul.diglio@sbcglobal.net" rel="nofollow" target="_blank">paul.diglio@sbcglobal.net</a>><br clear="none">
To: Equest-users <<a shape="rect" href="mailto:equest-users@lists.onebuilding.org" rel="nofollow" target="_blank">equest-users@lists.onebuilding.org</a>><br clear="none">
Cc: <br clear="none">
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Date: Mon, 9 Dec 2019 11:13:13 +0000 (UTC)<br clear="none">
Subject: [Equest-users] UA Convergence Error<br clear="none">
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<div dir="ltr">Hi Folks:</div>
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<div dir="ltr">I am getting a "heat exchanger XX Sys1 UA calculation failed to converge" error.  The model has three building in it and only two air handlers per building.  I don't have any heat exchangers attached to the air handlers or any heat recovery installed.<br clear="none">
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<div dir="ltr">Sometimes the error occurs when I change the glass type via the library and other times I get the error when I adjust the air changes per hour in one or two zones.</div>
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<div dir="ltr">In the example above, the error was for system B2, but it varies...sometimes systems A or C 1 or 2.</div>
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<div dir="ltr">Any ideas what the problem could be?  <br clear="none">
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<div dir="ltr">Thank you,<br clear="none">
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<div>Paul Diglio<br clear="none">
87 Fairmont Avenue <br clear="none">
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