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<p>Miguel,</p>
<p> If your 3-way valve is acting as a tempering valve then there
are some tempering valve components in the TESS controllers
library that you can use. The difficulty in using a PID controller
in a situation like yours is that the simulation time step is
quite long in comparison to the time constant of the valve. If you
really want to model PID then it is far easier to do with
something where the time constant of the process being modeled is
long in comparison to the time step of the simulation. The
tempering valve model knows the temperature of the sources (A and
B) and knows the temperature that you are trying to mix to so it
can compute analytically the steady state solution; the ratio of A
and B that will result in C.</p>
<p>kind regards,</p>
<p> David</p>
<p><br>
</p>
<br>
<div class="moz-cite-prefix">On 03/21/2017 08:30, Miguel Angel Reyes
via TRNSYS-users wrote:<br>
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<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-US">Is there any existing
type of a controlled valve by using a PID.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">In my problem I would
like using three-ways valve where ports A and B are joining
into an outlet C port. I would like controlling the outlet
temperature of port C by modifying the opening of port B
(this is from a hot recirculating stream).<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Kind Regards<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="ES">---------------------------------------------------<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="ES">Miguel</span><o:p></o:p></p>
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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>
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