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Damien,<br>
As far as your question 2/ is concerned, my guess is that the time
step in question did not converge. When components do not converge
after a certain number of iterations, TRNSYS stops iterating and
makes the "end of time step" call, then goes on to the next time
step. In earlier versions of TRNSYS, this was referred to as the
"post convergence" call but really that is poorly named since that
call is made whether or not convergence was reached.<br>
<br>
Check to make sure that there is some thermal capacitance in your
flow loop and that your time step is not too big. If you have
simplified the loop by omitting the piping or if you are using too
long a time step convergence of the controls becomes very
challenging.<br>
Kind regards,<br>
David<br>
<br>
<br>
<div class="moz-cite-prefix">On 5/7/2013 06:27, Damien Casetta
wrote:<br>
</div>
<blockquote
cite="mid:CA+b-pK4agJfUxzYu7bhzfvPg__q6a3Yfd5xtWtd+uKiBjBvjWQ@mail.gmail.com"
type="cite">
<div dir="ltr">Hi,
<div><br>
</div>
<div style="">Thanks Ciarán for your help. However, the .lst
file doesn't say much more about the errors. <br>
<br>
1/ The unit number (24) is not written on the input file.
Plus, the associated type changes (and is not in the current
simulation in most cases) each time I get this error. Let's
forget about this then. <br>
<br>
2/ The second error ("a negative flow rate was encountered")
has retained my attention (first of all because it stops the
simulation) and I would be glad if I could draw your attention
on this issue. Please find attached the TRNSYS model and refer
to it for unit and type numbers. As you can see I have traced
the critical components to better understand the error. Here
is what happens : </div>
</div>
</blockquote>
<blockquote
cite="mid:CA+b-pK4agJfUxzYu7bhzfvPg__q6a3Yfd5xtWtd+uKiBjBvjWQ@mail.gmail.com"
type="cite">
<div dir="ltr">
<div style="">- During post-convergence call, mass balance is
not achieved through the first tee piece (Type 11, Unit 55).
Input flow rates are 339,8 kg/hr and 0 kg/hr whereas output
flow rate is 339,6 kg/hr (equal to iteration 0 and 1 of the
current time step and to the converged value of the previous
time step). Right after this, in the lst file, a fatal error
is detected (no unit specified), as attached in my previous
message. Does it occur at iteration 0 of the next time step?
Why is it post-convergence call (current time step) if a
simple mass balance is not checked? <br>
<br>
Feel free to ask if you need more info about the project,</div>
<div style=""><br>
Thanks a lot for helping me on this, </div>
<div style=""><br>
</div>
<div style="">Have a nice day,</div>
</div>
<div class="gmail_extra"><br clear="all">
<div>
<div dir="ltr">
<div><font color="#999999"><b>Damien Casetta</b></font></div>
<div><br>
</div>
<div><font color="#3366FF"><b>INSA Lyon</b> Génie
Énergétique et Environnement</font></div>
<div> <span style="color:rgb(153,153,153)"> </span></div>
<div><span style="color:rgb(153,153,153)">+33.6.71.78.03.75</span></div>
</div>
</div>
<br>
<br>
<div class="gmail_quote">On 3 May 2013 16:41, Flynn Ciaran <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:ciaran.flynn@aalto.fi" target="_blank">ciaran.flynn@aalto.fi</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div link="blue" vlink="purple" lang="EN-US">
<div>
<div>
<div>
<div>
<div>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hey
Damien,</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Click
on the “Lst file…” tab, you can see it from
the screenshot you took. This will open your
lst file and when you scroll to the bottom
of it you will get more information about
the type of errors you are getting.<br>
(Note that to access this file directly, go
to the same directory as your trnsys file
and it’s the text file in the same name)</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Hope
this helps,</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Bon
wkd,</span></p>
<p class="MsoNormal"><span
style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Ciarán</span></p>
<div>
<p class="MsoNormal"> </p>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<br>
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<br>
</blockquote>
</div>
<br>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI 53703 USA
P:+1.608.274.2577
F:+1.608.278.1475
<a class="moz-txt-link-abbreviated" href="mailto:d.bradley@tess-inc.com">d.bradley@tess-inc.com</a>
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<a class="moz-txt-link-freetext" href="http://www.trnsys.com">http://www.trnsys.com</a></pre>
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