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<p>László,</p>
<p> The capacitance of the walls is definitely taken into account
although not in the same way that the capacitance of the stuff in
the zones is taken into account. The walls are made up of layers;
for each layer you provide the material's density, specific heat,
and thermal conductivity. Those values as well as the thickness of
each layer and the order of the layers are used to generate a set
of values called conduction transfer function coefficients. Those
coefficients are made for discreet steps backwards in time (like a
time step but in this case it is called a time base). If there is
a mismatch between the time constant of your wall and the timebase
that you have selected (in the "outputs" window of TRNBuild) then
I suppose that changes in the capacitance of the walls might not
show up in the results. Say for example you have selected a 1hr
timebase but the wall has a low thermal capacitance such that its
time constant is more like 15 minutes. Changes to the capacitance
that don't significantly extend the time constant of the wall
might not show in the results. <br>
</p>
<p> You can also get into some problems if you have a high thermal
capacitance wall, which sometimes you have to treat as "resistive
only" in TRNBuild due to the way that the conduction transfer
function coefficients are generated. If you have had to treat the
wall as a thermal resistance then the capacitance doesn't enter
into the treatment of the walls.</p>
<p>kind regards,</p>
<p> David</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 07/25/2022 05:42, Gergely László
Zsolt wrote:<br>
</div>
<blockquote type="cite"
cite="mid:PR3P195MB0473DDE40EFA2E7260CD7C40BF959@PR3P195MB0473.EURP195.PROD.OUTLOOK.COM">
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<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
Dear All,<br>
<br>
Still need your help with this.<br>
Running some simulations changing capacitance values (despite
the manual mentions that this value stands for the air and the
furnitures and walls shall not be considered here) of the
airnode and capacitance of the layers I am not convinced that
calculations consider the capacitance of the walls!<br>
<br>
Could you help me out?</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
<br>
</div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);" class="elementToProof">
Regards,</div>
<div>
<div style="font-family: Calibri, Arial, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div id="Signature">
<div>
<div style="font-family: Calibri, Arial, Helvetica,
sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<div style="margin:0px;font-size:12pt"><span
style="margin:0px;font-size:10pt;font-family:"Sitka
Heading", Cochin, serif;color:rgb(134, 17,
6);text-align:start;background-color:white"><b>László
GERGELY</b></span><br>
<span
style="margin:0px;font-size:10pt;font-family:"Sitka
Heading", Cochin, serif;color:rgb(134, 17,
6);text-align:start;background-color:white">PhD stude</span><span
style="margin:0px;font-size:10pt;font-family:"Sitka Heading",
Cochin, serif;color:rgb(134, 17, 6)">nt, Building
Energy Engineering</span></div>
<div style="margin:0px;font-size:12pt"><span
style="margin:0px;font-size:10pt"></span><span
style="margin:0px;font-size:10pt;font-family:"Sitka
Heading", Cochin, serif;color:rgb(134, 17,
6);text-align:start;background-color:white">Budapest </span><span
style="margin:0px;font-size:10pt;font-family:"Sitka Heading",
Cochin, serif;color:rgb(134, 17, 6)">University of
Technology and Economics</span></div>
<span style="margin:0px;font-size:12pt"><img
style="margin:0px;font-size:16px;width:129px;height:41px;max-width:100%"
data-outlook-trace="F:1|T:1"
src="cid:part1.Jvg6f0xo.U3HNSdZY@tess-inc.com"
class="" width="129" height="41"></span><br>
</div>
</div>
</div>
</div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>Feladó:</b>
TRNSYS-users
<a class="moz-txt-link-rfc2396E" href="mailto:trnsys-users-bounces@lists.onebuilding.org"><trnsys-users-bounces@lists.onebuilding.org></a>,
meghatalmazó: Gergely László Zsolt via TRNSYS-users
<a class="moz-txt-link-rfc2396E" href="mailto:trnsys-users@lists.onebuilding.org"><trnsys-users@lists.onebuilding.org></a><br>
<b>Elküldve:</b> 2022. július 22., péntek 17:48<br>
<b>Címzett:</b> TRNSYS users mailing list at OneBuilding.org
<a class="moz-txt-link-rfc2396E" href="mailto:trnsys-users@lists.onebuilding.org"><trnsys-users@lists.onebuilding.org></a>; David BRADLEY
<a class="moz-txt-link-rfc2396E" href="mailto:d.bradley@tess-inc.com"><d.bradley@tess-inc.com></a><br>
<b>Másolatot kap:</b> Gergely László Zsolt
<a class="moz-txt-link-rfc2396E" href="mailto:gergely.laszlo@gpk.bme.hu"><gergely.laszlo@gpk.bme.hu></a><br>
<b>Tárgy:</b> [TRNSYS-users] Type 56 thermal mass</font>
<div> </div>
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<div class="x_elementToProof"
style="font-family:Calibri,Arial,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
Dear All,<br>
</div>
<div class="x_elementToProof"
style="font-family:Calibri,Arial,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<br>
For some reasons I believe that my simulations do not consider
thermal capacitance of my building.<br>
I have no idea what goes wrong... I thought about overwriting
the capacitance value of the zones however based on the
documentation that value shall not include wall capacitance.<br>
<br>
In the enclosed project there is a nightime setback and the
problem is visible as the temperature drops as soon as the
heating is off and rises as soon as it is on.<br>
<br>
To make things in context the aim of the project is testing
different options reducing heating demand.</div>
<div class="x_elementToProof"
style="font-family:Calibri,Arial,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<br>
</div>
<div class="x_elementToProof"
style="font-family:Calibri,Arial,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
Do you have any suggestions for overcoming the problem?<br>
I would be grateful!</div>
<div class="x_elementToProof"
style="font-family:Calibri,Arial,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<br>
</div>
<div class="x_elementToProof"
style="font-family:Calibri,Arial,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
Thanks in advance,</div>
<div>
<div style="font-family:Calibri,Arial,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<br>
</div>
<div id="x_Signature">
<div>
<div
style="font-family:Calibri,Arial,Helvetica,sans-serif;
font-size:12pt; color:rgb(0,0,0)">
<div style="margin:0px; font-size:12pt"><span
style="margin:0px; font-size:10pt;
font-family:"Sitka Heading",Cochin,serif;
color:rgb(134,17,6); text-align:start;
background-color:white"><b>László GERGELY</b></span><br>
<span style="margin:0px; font-size:10pt;
font-family:"Sitka Heading",Cochin,serif;
color:rgb(134,17,6); text-align:start;
background-color:white">PhD stude</span><span
style="margin:0px; font-size:10pt;
font-family:"Sitka Heading",Cochin,serif;
color:rgb(134,17,6)">nt, Building Energy Engineering</span></div>
<div style="margin:0px; font-size:12pt"><span
style="margin:0px; font-size:10pt"></span><span
style="margin:0px; font-size:10pt;
font-family:"Sitka Heading",Cochin,serif;
color:rgb(134,17,6); text-align:start;
background-color:white">Budapest </span><span
style="margin:0px; font-size:10pt;
font-family:"Sitka Heading",Cochin,serif;
color:rgb(134,17,6)">University of Technology and
Economics</span></div>
<span style="margin:0px; font-size:12pt"><img
style="margin:0px; font-size:16px; width:129px;
height:41px; max-width:100%"
data-outlook-trace="F:2|T:2"
src="cid:part2.B1KQC11W.t9TP7xJS@tess-inc.com"
class="" width="129" height="41"></span><br>
</div>
</div>
</div>
</div>
</div>
</blockquote>
<pre class="moz-signature" cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy System 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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