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<p>Hi Toni</p>
<p><br>
</p>
<p></p>
<div>I assume that by reducing the distance, the tube length has also increased. Does this happen?<br>
By approximating the ACT layer, the return temperature can drop below the core temperature because the fluid temperature decreases over the length of the tube. To avoid this, you need a minimum mass flow.  In order to reproduce a realistic temperature curve,
 you can make the layers smaller. But be carefull with the IN and OUT temperature.</div>
<div>Here you will find a detailed description: "<span>Koschenz, Markus / Lehmann, Beat: Thermoaktive Bauteile tabs. [1. Aufl.], Dübendorf: EMPA Energiesysteme/Haustechnik, 2000. S.25"</span></div>
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<div><span>kind regards from antohter David</span><br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>Von:</b> TRNSYS-users <trnsys-users-bounces@lists.onebuilding.org> im Auftrag von David BRADLEY via TRNSYS-users <trnsys-users@lists.onebuilding.org><br>
<b>Gesendet:</b> Montag, 8. Februar 2021 15:06:48<br>
<b>An:</b> TRNSYS users mailing list at OneBuilding.org<br>
<b>Cc:</b> David BRADLEY<br>
<b>Betreff:</b> Re: [TRNSYS-users] Problem with Active Layer</font>
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<div>***** ACHTUNG! Dies ist eine externe Mail. Öffnen Sie keine Anhänge und klicken Sie nicht auf enthaltene Links, solange Sie dem Absender nicht trauen und wissen, dass der Inhalt sicher ist *****
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<p>Toni,</p>
<p> I have run into this problem from time to time as well and was never able to discover the cause. I found that if I increased the flow rate to about 1.1 times the stated required flow the the error usually went away. The other thing you can do, of course,
 is to segment the floor so that it will allow you to enter the flow that you wanted.</p>
<p>kind regards,</p>
<p> David</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 02/08/2021 03:08, Toni Calabrese via TRNSYS-users wrote:<br>
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<blockquote type="cite" cite="mid:VE1PR09MB32141041313CB9E36E6CB36DE98F9@VE1PR09MB3214.eurprd09.prod.outlook.com">
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<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D" lang="EN-US">Hi everyone,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D" lang="EN-US">For a pilot project we are analyzing a heating system in which an "external wall heating system" is installed on the façade. Basically we have a wall with an active layer that is
 insulated on the back in order to decrease the losses of this active layer to the outside.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D" lang="EN-US">With a pipe spacing of 13.5 cm the system was working good. For a parametric study, I would like to run a study varying the pipe spacing. Setting the pipe spacing to 10 cm (instead
 of 13.5 cm) the system does not simulate anymore. It gives me the following error:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt" lang="EN-US">Message               : Specific fluid mass flow of active layer in surface   24 below minimum value of 8.01 kg/m2h Please, increase the minimum mass flow rate or use the autosegmentation feature
 of TRNBuild for subdividing the surface.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D" lang="EN-US">I checked the massflow rate and I am sure that the mass flow rate is higher than the minimum. I tried to increase the massflow rate through the pump of the system but it does not
 work. Which is the problem?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D" lang="EN-US">Here the data of my simulation:<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span style="font-size:10.0pt;color:#1F497D" lang="EN-US"><span style="mso-list:Ignore">-<span style="font:7.0pt
                "Times New Roman"">       
</span></span></span><!--[endif]--><span style="font-size:10.0pt" lang="EN-US">TRNSYS 17<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span style="font-size:10.0pt;color:#1F497D" lang="EN-US"><span style="mso-list:Ignore">-<span style="font:7.0pt
                "Times New Roman"">       
</span></span></span><!--[endif]--><span style="font-size:10.0pt" lang="EN-US">Wall area: 10.16 m2<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-18.0pt;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span style="font-size:10.0pt;color:#1F497D" lang="EN-US"><span style="mso-list:Ignore">-<span style="font:7.0pt
                "Times New Roman"">       
</span></span></span><!--[endif]--><span style="font-size:10.0pt" lang="EN-US">Massflow rate system: 86 kg/h<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt" lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D" lang="EN-US"><o:p> </o:p></span></p>
<div class="MsoNormal" style="text-align:center" align="center"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">
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<p class="MsoNormal" style="margin-top:4.0pt"><b><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">Toni Calabrese</span></b><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">, MSc.</span><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">Wissenschaftlicher Projektmitarbeiter<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH"><a href="mailto:toni.calabrese@spf.ch" moz-do-not-send="true"><span style="color:#0065A3">toni.calabrese@spf.ch</span></a> |</span><span style="font-size:10.0pt;color:#8C195F;mso-fareast-language:DE-CH">
</span><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH"><a href="mailto:toni.calabrese@ost.ch" moz-do-not-send="true"><span style="color:#0065A3">toni.calabrese@ost.ch</span></a></span><span style="font-size:10.0pt;color:#8C195F;mso-fareast-language:DE-CH"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Calibri",sans-serif;color:#8C195F;mso-fareast-language:DE-CH"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">T +41 58 257 4827<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">SPF Institut für Solartechnik<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">OST – Ostschweizer Fachhochschule<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">Oberseestr. 10 | CH-8640 Rapperswil | Switzerland |
</span><u><span style="color:#8C195F;mso-fareast-language:DE-CH"><a href="http://www.spf.ch" moz-do-not-send="true"><span style="font-size:10.0pt;color:#8C195F">www.spf.ch</span></a></span></u><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH">
 | </span><u><span style="color:#8C195F;mso-fareast-language:DE-CH"><a href="http://www.ost.ch" moz-do-not-send="true"><span style="font-size:10.0pt;color:#8C195F">www.ost.ch</span></a></span></u><span style="font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:DE-CH"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#1F497D;mso-fareast-language:DE-CH"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;color:#1F497D">OST – Ostschweizer Fachhochschule ist der Zusammenschluss aus FHS St.Gallen, HSR Rapperswil und NTB Buchs.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
TRNSYS-users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:TRNSYS-users@lists.onebuilding.org">TRNSYS-users@lists.onebuilding.org</a>
<a class="moz-txt-link-freetext" href="http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org</a>
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<pre class="moz-signature" cols="72">-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
3 North Pinckney Street - suite 202
Madison, WI  53703 USA

P:+1.608.274.2577
<a class="moz-txt-link-abbreviated" href="mailto:d.bradley@tess-inc.com">d.bradley@tess-inc.com</a>

<a class="moz-txt-link-freetext" href="http://www.tess-inc.com">http://www.tess-inc.com</a>
<a class="moz-txt-link-freetext" href="http://www.trnsys.com">http://www.trnsys.com</a></pre>
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