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<p>David,</p>
<p> I did not take the time to run the project but there are two
issues that need to be resolved. <br>
</p>
<p>The first is the 1-hour time step; I would guess that part of the
problem is non convergence due to the long time step. The pump on
the hot water side of the absorption chiller has a flow rate of
58000 kg/h and the tank is 5m3. That means that in each time step,
the tank volume turns over a bit more than 11 times. The flow rate
on the collector loop is 20000 kg/h causing another 4 turnovers in
each time step. I would start by reducing the time step to about 5
minutes.</p>
<p> The other issue is that you have two devices in the collector
loop that are both trying to set the flow rate in that loop.
Type110 is being controlled by an on/off differential controller
but your collector is also set up in Pump Control Specification
mode 2 (an input), which means that the collector model is
modulating its own flow in order to deliver a specified outlet
temperature.</p>
<p>kind regards,</p>
<p> David</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 11/03/2020 11:17, David Redpath
(Staff) via TRNSYS-users wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CWLP265MB0979D9C848C867808A027C89CA110@CWLP265MB0979.GBRP265.PROD.OUTLOOK.COM">
<pre class="moz-quote-pre" wrap="">
Hi,
I'm trying to simulate a system with a single effect absorption chiller (project file attached) however I keep getting an error saying pump mass balance failed, is there a way of calculating the correct mass balance. Any help gratefully appreciated. Thanks
David
</pre>
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<pre class="moz-signature" cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
3 North Pinckney Street - suite 202
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