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<p>Jorge,</p>
<p> It sounds like there might be two issues going on here. One is
the connection between the radiator and the building and the other
is the connection between the radiator and the heat pump. I would
suggest trying to separate the two problems. First, run your
building with its radiator. From what you describe, it sounds as
though your connections are correct. Put an ideal temperature and
flow rate of water into the radiator and make sure that the water
coming out of the radiator and the building both react as
expected. Next, put a forcing function onto the flow rate going
into the radiator and make sure that it still makes sense.</p>
<p> Once you are sure that the radiator is getting heat into the
building and that the water comes out of the radiator at a
reasonable temperature then add a pump, piping, and the heat pump
back in. The pump is there to control the flow obviously. The
pipes are there to make sure that you have thermal capacitance in
your liquid loop. Make sure that the volume of liquid moved by the
pump in one time step is less than the volume of the piping. If it
isn't, you can get convergence problems.<br>
</p>
<p> The COP at which the heat pump operates is a function not only
of the air temperature on its source side but also of the
returning water temperature on its load side. If the COP increases
when the ambient temperature decreases while the entering water
temperature stays the same then you'll need to look at the
performance data file that you're using as it may have a problem.
<br>
</p>
<p>kind regards,</p>
<p> David</p>
<p> <br>
</p>
<div class="moz-cite-prefix">On 03/24/2021 09:50, Jorge Ignacio
Ortega Arriagada via TRNSYS-users wrote:<br>
</div>
<blockquote type="cite"
cite="mid:a00963551beea3e977fde93d40dc859d@udec.cl">Hello,
<br>
<br>
I have a question about Type 1231, how does it connect to type 56?
The radiator model is connected to a heat pump.
<br>
<br>
I have connected the radiator heat as a gain (through gain type
manager) that brings radiation and convection to the house,
however, I have noticed that the SCOP of the heat pump increases
as the ambient temperature decreases, which is not possible (I
have tested for different climatic conditions in Chile). In my
model, I found the problem in Type 1231, which causes this
anomaly. As radiator inputs connect the water flow and water
temperature from the heat pump (type 941). From type 56 connect
the indoor temperature of the house to the radiator model.
<br>
<br>
I would like some help on this, please.
<br>
<br>
</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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