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Brian,<br>
In your example of a tank and an auxiliary heater you are correct
that the first component appearing in the input file determines the
flow for both. The order of components in the input file is
determined by the order in which they were placed on the assembly
panel in the Studio. However, you can modify the order by opening
the control cards (where you set the simulation start and stop
times) and then by clicking on the "component order" tab. Click and
drag components around the list to change their order.<br>
<br>
TRNSYS typically uses the "successive substitution" method to
solve the system of components. The outputs of one component are
substituted into the inputs for the components to which that output
is connected. Each component takes its current set of inputs and
computes its outputs, passing them back to the TRNSYS kernel
(brains) to see whether they have changed from the previous
iteration. Once everything stops changing from iteration to
iteration the kernel decides that convergence has been reached and
advances to the next timestep.<br>
<br>
Your example changes somewhat if you put a pump into the system.
Pumps and fans in TRNSYS control the downstream flow. The output
flow rate from a pump or a fan is the rated flow rate multiplied by
the control signal (usually; there are some components that do not
conform to this method). The flow rate from the pump or fan is then
passed to the downstream components and should get passed all the
way around the flow loop such that there is a mass balance. Most
pump and fan models issue a warning as to how much of the simulation
their mass balance failed.<br>
<br>
kind regards,<br>
David<br>
<br>
<br>
<div class="moz-cite-prefix">On 02/17/2016 21:07, Brian Raichle
wrote:<br>
</div>
<blockquote
cite="mid:CAKB7ZvmjymvhFxj4Zm1bES_Z2To5renL_XQpoFQRcobDqNs_OQ@mail.gmail.com"
type="cite">
<div dir="ltr">Here's a general question about how TRNSYS
operates:
<div><br>
</div>
<div>Suppose 2 components are linked, for example flow from a
tank to an auxiliary heater and back to the tank. Both
component's inputs has a default flow value. How does TRNSYS
determine which flow to use? </div>
<div><br>
</div>
<div>My only guess is ordering of the components in the dck
file. First component listed determines the value? Then what
determines component ordering in the dck file? </div>
<div><br>
</div>
<div>Thanks!</div>
<div>Brian<br>
<div>
<div><br>
</div>
-- <br>
<div class="gmail_signature">
<div dir="ltr">Brian W. Raichle
<div>Professor and Assistant Chair</div>
<div>Department of Sustainable Technology & the
Built Environment</div>
<div>Appalachian State University</div>
</div>
</div>
</div>
</div>
</div>
<br>
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<pre class="moz-signature" cols="72">--
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI 53703 USA
P:+1.608.274.2577
F:+1.608.278.1475
<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>
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