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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Hello Jean,<br>
<br>
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Thank you for this solution.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Actually, we have numerous windows in the model.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">It could be a good option to help the model convergence.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Kind regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Hugo<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>De :</b> TRNSYS-users <trnsys-users-bounces@lists.onebuilding.org>
<b>De la part de</b> Jean Marais via TRNSYS-users<br>
<b>Envoyé :</b> vendredi 8 janvier 2021 09:47<br>
<b>À :</b> TRNSYS users mailing list at OneBuilding.org <trnsys-users@lists.onebuilding.org><br>
<b>Cc :</b> Jean Marais <jeannieboef@gmail.com><br>
<b>Objet :</b> Re: [TRNSYS-users] Convergence problem for the internal regulation<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">You could also try staggering the window opening events so that they don't all open at once, but slightly delayed from one another.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Am Do., 7. Jan. 2021 um 22:36 Uhr schrieb David BRADLEY via TRNSYS-users <<a href="mailto:trnsys-users@lists.onebuilding.org">trnsys-users@lists.onebuilding.org</a>>:<o:p></o:p></p>
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<p>Hugo,<o:p></o:p></p>
<p> This kind of problem is not uncommon, especially when doing combined airflow/thermal simulations. I have not run into the problem of convergence problems inside of Type56, which is a little surprising. I thought that I had gotten all of the possible TRNSYS
errors at least once! The solution I usually use is to implement a short time step (1 minute perhaps) and then to put a delay component (like Type661 or Type150) between Type56's output temperatures and Type98's inputs. It is a bit of a cheat but I think with
a short timestep it is realistic enough. We assume that air entering a Type56 zone immediately mixes thermally with the zone air and that thermostats react immediately. When you add the automatic heating/cooling that Type56 can do you are further assuming
that the mechanical systems can react instantaneously and provide exactly the right amount of heating and cooling. I don't think it is unreasonable to introduce back a small time delay in order to get the whole thing to converge.<o:p></o:p></p>
<p>kind regards,<o:p></o:p></p>
<p> David<o:p></o:p></p>
<p> <o:p></o:p></p>
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<p class="MsoNormal">On 01/07/2021 09:05, Hugo GEOFFROY via TRNSYS-users wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Hello,
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">We need to modelize a few stories building in a cosimulation TRNSYS/CONTAM.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">The thermal part is handled by TRNSYS with a Type 56 and the aeraulic part by CONTAM with a Type 98.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">The model works but encounters several convergence problems as noticed in the *.lst file. The model includes daily windows openings that coincide with the convergence
problem occurrences. Furthermore, most of the rooms are heated with an ideal system of which power is limited to 100 W.m-2. The setpoint temperature is fixed thanks to a schedule in the "Heating type manager"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Removing this heating resolves the convergence problem, but these convergence faults cannot be fixed by reducing the time step, modifying the number of iterations,
or convergence tolerance of Simulation Studio. The following error message shows that the faults are not directly generated in the "simulation studio" calculation but by Type 56 and are indeed a consequence of the heating of the building Type 56 model.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black">--------------------------------------------------------</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black">*** Notice at time : 130.000000</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black"> Generated by Unit : 56</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black"> Generated by Type : 56</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black"> Message : TIME = 130.000 More than 6 iterations for internal regulation HEATING/COOLING</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black">*** Warning at time : 130.000000</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black"> Generated by Unit : 56</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black"> Generated by Type : 56</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black"> Message : TIME = 130.000 CONVERGENCE NOT ATTAINED USING INTERNAL REGULATION FOR HEATING/COOLING</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:12.0pt;color:black">-------------------------------------------------------</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">This fault appears while the *.dck maximal iteration is fixed to 500.</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Has somebody already encountered this problem in Simulation studio ?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Is it possible and if yes, how the numerical parameters (tolerance of convergence, number of iterations, …) of Type56 can be modified? Do you have any idea for
another solution to solve this problem?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Thank you<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<pre>_______________________________________________<o:p></o:p></pre>
<pre>TRNSYS-users mailing list<o:p></o:p></pre>
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<pre><a href="http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org" target="_blank">http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org</a><o:p></o:p></pre>
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<pre>-- <o:p></o:p></pre>
<pre>***************************<o:p></o:p></pre>
<pre>David BRADLEY<o:p></o:p></pre>
<pre>Principal<o:p></o:p></pre>
<pre>Thermal Energy Systems Specialists, LLC<o:p></o:p></pre>
<pre>3 North Pinckney Street - suite 202<o:p></o:p></pre>
<pre>Madison, WI 53703 USA<o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre>P:+1.608.274.2577<o:p></o:p></pre>
<pre><a href="mailto:d.bradley@tess-inc.com" target="_blank">d.bradley@tess-inc.com</a><o:p></o:p></pre>
<pre><o:p> </o:p></pre>
<pre><a href="http://www.tess-inc.com" target="_blank">http://www.tess-inc.com</a><o:p></o:p></pre>
<pre><a href="http://www.trnsys.com" target="_blank">http://www.trnsys.com</a><o:p></o:p></pre>
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