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<p>László,</p>
<p> The most common problem when dealing with non convergence is
too long a timestep or not enough thermal capacitance in the
liquid loop. I would recommend running with no more than a 5
minute time step and that you estimate the volume of liquid in
your floor heating loop. Make sure that you have piping or a
buffer tank whose volume is at least as large as the larger of the
estimated volume and the amount of liquid that the pump can push
in one time step.</p>
<p>kind regards,</p>
<p> David</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 08/30/2021 08:01, Gergely László
Zsolt via TRNSYS-users wrote:<br>
</div>
<blockquote type="cite"
cite="mid:PR3P195MB047360364885980F9C7696FBBFCB9@PR3P195MB0473.EURP195.PROD.OUTLOOK.COM">
<meta http-equiv="Content-Type" content="text/html;
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
Dear All,<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<br>
I am trying to simulate Type 941 air-to-water heat pump system
(file Multizone_AWHP_V2_H&C_08.30_BP.idf), directly
connected to floor heating and slab cooling, however the model
does not work for some reasons. Trnsys message 441 comes up,
saying that some listed inputs have not coverged during the
simulation. It seems to occur escpecially in case of heating -
the simulation does not even finish. However, in case of cooling
the model seems to work - starting with June the simulation goes
on until the first periods of heating. <br>
<br>
Do you have any ideas what the problem could be and how to solve
it? <br>
Would really appreciate it!<br>
<br>
Also, it is strange that it is the case for Budapest weather
data, or all other that needs heating a lot. In case of Sydney
weather, it seems to run properly
(Multizone_AWHP_V2_H&C_08.26_massflow.idf). I am also
attaching a file calculating the heat loads for a specific case
(Multizone_AWHP_HeatLoads.idf)<span
style="background-color:rgb(255, 255, 255);display:inline
!important">, and the building itself
(AWHP_V2_H&C_08.26.b18)</span><br>
<br>
Hope you have solutions!<br>
Thank you in advance,</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<span style="margin:0px;font-family:"Sitka Heading",
Cochin, serif;color:rgb(12, 100,
192);background-color:rgb(255, 255, 255)"><b>Laszlo GERGELY</b></span><br>
<span style="margin:0px;font-family:"Sitka Heading",
Cochin, serif;color:rgb(12, 100,
192);background-color:rgb(255, 255, 255)">PhD student</span><br
style="background-color:rgb(255, 255, 255)">
<span style="margin:0px;font-family:"Sitka Heading",
Cochin, serif;color:rgb(12, 100,
192);background-color:rgb(255, 255, 255)">Budapest University
of Technology and Economics</span><br>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
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</pre>
</blockquote>
<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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