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<p>Jim,</p>
<p> Your project connections are correct. I think your description
of the building sounds reasonable too. I can't be 100% sure that
the implementation is correct as I would need the look in the
*.b18 file as well.</p>
<p><br>
</p>
<p> The issues that you are running into with the heat pump and
building are almost always caused by using too long a timestep
(this should be on the order of 1 to 5 minutes) and/or a heat pump
that is not sized correctly for the zone that it is serving. I'm
not sure how you have handled the conditioning in the zones that
are not served by the heat pump but I would recommend putting them
into energy rate control while you are adding heat pumps. Each
time you add a heat pump to a zone you'll want to turn off that
zone's automatic/idealized heating and cooling. The problem is
that if all but one zone is unconditioned, the additional load on
the one conditioned zone (from all of its unconditioned neighbors)
causes the heat pump to be undersized until the neighboring zones
are also conditioned.</p>
<p>kind regards,</p>
<p> David</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 08/26/2021 15:47, dimitris soukoulis
via TRNSYS-users wrote:<br>
</div>
<blockquote type="cite"
cite="mid:VI1PR08MB35032C44E4A761932C7B5691A7C79@VI1PR08MB3503.eurprd08.prod.outlook.com">
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Greetings community. </div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);"
id="geom_inter_1630010826961_92_17">
I am modelling a multizone building and I have two questions.</div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);"
id="geom_inter_1630010826962_78_18">
First, I would like to know if I am modelling the geometry
correctly (through the TRNbuild wizard). It is a two floor
apartment building with two apartments in each floor, so in the
floorplan window, I model it as two separate floors (three zones
each, with the middle zones representing the hallways)-as shown
in the picture- and then connecting the floors with adjacent
floors ( or ceilings). Is that the right way ? </div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
Secondly, I am constantly running into problems with the air
pump system I am using. I have tried both approaches -DOE
coefficient and catalog data- type 966 and 954 respectively, but
I cant seem to solve the warnings and errors of the simulation.
Some common problems i get are: Error 118 (SAT subroutine was
called with a temperature below absolute zero), fail of input
convergence, controller (Type 166) sticks for a considerable
amount of timesteps. I also experience a very slow simulation
even with a timestep of 1 hour. I have tried many things like
short timestep, calibrating the heat pumps capacity, increasing
the zone's thermal capacitance, using the absolute instead of
the relative humidity etc. but when I manage to erase one
problem the other appears.</div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
If anyone has some idea about what might be going wrong in my
case I would be reaally grateful, considering the time I have
consumed trying to get it right. I attached the .tpf of the
simulation for better a understanding of my project. <span
style="background-color:rgb(255, 255, 255);display:inline
!important">Looking forward for your ideas.</span></div>
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font-size: 12pt; color: rgb(0, 0, 0);">
<span style="background-color:rgb(255, 255, 255);display:inline
!important"><br>
</span></div>
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font-size: 12pt; color: rgb(0, 0, 0);">
<span style="background-color:rgb(255, 255, 255);display:inline
!important">Thanks in advance,</span></div>
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font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div style="font-family: Calibri, Helvetica, sans-serif;
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Jim Soukoulis</div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
National Technical University of Athens.</div>
<div style="font-family: Calibri, Helvetica, sans-serif;
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</div>
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</div>
<br>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
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</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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