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Mike,<br>
I think your simulation is correct (nice job, incidentally, in
setting it up). I think the "problem" is that your collector is just
too small to collect enough energy to add to the tank. As a result,
whenever there is flow through the collector, the temperature rise
is so small that the outlet temperature basically equals the inlet
temperature and the controller decides to turn off. Imagine the
limit; if you had a collector that had zero area, it couldn't
collect any energy; it would just a pipe of water sitting in the
sun. When there is no flow, the pipe heats up, the water gets hot,
and the controller decides to turn on the pump. However, as soon as
the flow starts, the water comes back to the tank at the same
temperature with which it left. I doubled the area of your collector
and suddenly it all went stable. <br>
<br>
I did clean up the connections between the weather processor and
the collector; there are a few more solar radiation connections that
need to be made (diffuse solar, incidence angle, etc.). You also
need to use Type69 to get the sky temperature. Alternatively (and
much preferably) you should change Type109 for Type15; Type15 also
reads TMY2/Meteonorm data files but has a number of advantages over
Type109 (including calculating the effective sky temperature
internally and outputting the wind speed.<br>
<br>
Regards,<br>
David<br>
<br>
On 9/22/2011 15:50, Michael Bissett wrote:
<blockquote
cite="mid:CAEWo59-f+cF2WEdKARo4-JUu-j4xF7a+Fs4kNautrisYq+n5Zw@mail.gmail.com"
type="cite">I have taken your advice and made the timestep,
0.125hr
<div><br>
</div>
<div>Still I cannot get it to work. it is still switching on the
time step instead of the dead-band temp.</div>
<div><br>
</div>
<div>Mike<br>
<br>
<div class="gmail_quote">
On Wed, Sep 21, 2011 at 3:33 PM, Matt Duffy <span dir="ltr"><<a
moz-do-not-send="true" href="mailto:duffy@tess-inc.com">duffy@tess-inc.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex;">
<br>
Dear Michael,<br>
<br>
Please make sure that you are using a reasonable timestep
such as 0.125 hr (type in terms of hours to avoid problems
with the Studio's minute conversion trucation). Also, make
sure that you have the latest TRNSYS and TESS Libraries
versions as well.<br>
<br>
Best regards,<br>
<font color="#888888"><br>
Matt Duffy<br>
<br>
</font>
<div style="background-repeat:repeat-x">
<div>
<div class="h5"><strong>----- Original Message -----</strong><br>
<strong>From:</strong> "Michael Bissett" <<a
moz-do-not-send="true"
href="mailto:mikebiscuit@gmail.com" target="_blank">mikebiscuit@gmail.com</a>>
<br>
<strong>Sent:</strong> Tue, September 20, 2011 12:44<br>
<strong>Subject:</strong> Re: [TRNSYS-users] Type 2b
controller dead band problem.<br>
<br>
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<div class="h5"> Hi
<div> </div>
<div>I have read the information, I have
tried to increase parameter 1, I have also
looped the controller to its self. Still
it does not work</div>
<div>I have also tried changing many other
parameters and have spent a lot of time on
this problem. still with no luck.</div>
<div> </div>
<div>Any other suggestions?</div>
<div> </div>
<div>Mike</div>
<div> </div>
<div> </div>
<div> </div>
<div><br>
<div class="gmail_quote">On Tue, Sep 20,
2011 at 1:59 PM, Angel Carrera <span
dir="ltr"><<a
moz-do-not-send="true"
href="mailto:angel.carrera@aiguasol.coop"
target="_blank">angel.carrera@aiguasol.coop</a>></span>
wrote:<br>
<blockquote style="margin:0pt 0pt 0pt
0.8ex;border-left:1px solid rgb(204,
204, 204);padding-left:1ex"
class="gmail_quote"><br>
Mike,<br>
<br>
you should connect the output control
function of the controller to its own
input control function (Input number
4). Also, you should increase the
value of parameter 1, to the default
value at least (the influence of this
parameter is explained at the type 2
documentation, I recommend you to read
it, together with the generic section
for controllers at the trnsys help)<br>
<br>
Regards<br>
<br>
Angel<br>
<br>
<br>
<div class="gmail_quote">
<div>
<div> </div>
<div>2011/9/19 Michael Bissett <span
dir="ltr"><<a
moz-do-not-send="true"
href="mailto:mikebiscuit@gmail.com"
target="_blank">mikebiscuit@gmail.com</a>></span></div>
</div>
<blockquote style="margin:0pt 0pt
0pt 0.8ex;border-left:1px solid
rgb(204, 204,
204);padding-left:1ex"
class="gmail_quote">
<div>
<div> </div>
<div>Dear Trnsys
<div> </div>
<div>I am experiencing
problems with a simple<b>
type 2b controller</b>.</div>
<div> </div>
<div>I am using a solar
collector type 564b</div>
<div> </div>
<div>I am trying to compare
the temperature of the
output of the collector with
output of the tank, getting
a temperature difference. I
have set the dead band from
4-10 degrees C.</div>
<div> </div>
<div>In the simulation as the
temperature rises to
10degrees difference, the
control signal is 1
switching the pump on
correctly. but after this
the controller only switches
every time step. I have
tried shortening the time
step... and changing other
parameters.. still with no
success.</div>
<div> </div>
<div>I have attached the file.</div>
<div> </div>
<div>Yours Sincerely</div>
<div> </div>
<div>Mike Bissett</div>
<div> </div>
<div>Department of Electrical
Engineering</div>
<div>University of Cape Town </div>
<div>
South Africa</div>
</div>
</div>
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</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
<font style="color:rgb(0, 102, 0)"
size="4"><b>Àngel Carrera</b></font><br
style="color:rgb(0, 102, 0)">
<br style="color:rgb(0, 102, 0)">
<b style="color:rgb(0, 102, 0)">Responsable
I+D<br>
Àrea tècnica</b><br
style="color:rgb(0, 102, 0)">
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<span style="color:rgb(0, 153, 0)">Sistemes
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<span style="color:rgb(0, 153, 0)">Tel:
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<font color="#888888"><br>
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href="mailto:angel.carrera@aiguasol.coop"
target="_blank">angel.carrera@aiguasol.coop</a><br>
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target="_blank">http://www.aiguasol.coop</a></font><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>
<a class="moz-txt-link-freetext" href="http://www.trnsys.com">http://www.trnsys.com</a></pre>
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