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Ali,<br>
I think what you are describing is just a simple thermostat in
cooling mode (turn something on if a temperature rises above a
certain setpoint and turn it off if the temperature falls below that
setpoint). You can use Type2. If you are using Trnsys17 then there
is already a Type2 proforma set up to do this in Controllers:
Aquastat: Cooling Mode: Type2-AquastatC. If you have Trnsys16 you
can set up Type2 to do the same. Input 2 becomes the setpoint (88C)
and Input 1 will be connected from the temperature of the bottom
node of your tank. The upper dead band will be 1C and the lower dead
band will be -1C. <br>
<br>
If you have the TESS Controllers Library, you will find models of
cooling aquastats in there as well.<br>
Kind regards,<br>
David<br>
<br>
<br>
<div class="moz-cite-prefix">On 2/24/2014 06:56, ali shirazi wrote:<br>
</div>
<blockquote
cite="mid:CAOQ0qjFFSMTjoBeN0QFj9ketBbwgtCUg2ZP4umGitt+a5QCkNA@mail.gmail.com"
type="cite">
<div dir="ltr">
<p class="MsoNormal"><span
style="font-size:12pt;line-height:115%;font-family:'Times
New Roman',serif" lang="EN-US">Dear Trnsys users,</span></p>
<p class="MsoNormal"><span
style="font-size:12pt;line-height:115%;font-family:'Times
New Roman',serif" lang="EN-US"><br>
</span></p>
<p class="MsoNormal"><span
style="font-size:12pt;line-height:115%;font-family:'Times
New Roman',serif" lang="EN-US">I am modeling a solar
assisted absorption chiller. In this system, a hot
water storage tank is used to store solar thermal energy.
The cycle is also equipped
with an auxiliary heater which is switched on in case the
tank temperature is
lower than a certain value. I need to generate a control
signal (either 0 or 1)
representing if the tank is on or off. The following briefly
describes the intended
control strategy:</span></p>
<p class="MsoNormal"><span
style="font-size:12pt;line-height:115%;font-family:'Times
New Roman',serif" lang="EN-US">The tank is on (control
signal=1) if the
bottom node temperature is greater than 88 C and it is
deactivated (control signal
value=0) in case the temperature at the top of the tank is
less than 88 C. In
this case, the tank could be charged while the auxiliary
heater is operating.</span></p>
<p class="MsoNormal"><span
style="font-size:12pt;line-height:115%;font-family:'Times
New Roman',serif" lang="EN-US">I suppose an on/off
differential controller would work for above mentioned
strategy (</span><span style="font-family:'Times New
Roman',serif;font-size:12pt;line-height:115%">an equation
box may
be needed to be used as well</span><span
style="font-family:'Times New
Roman',serif;font-size:12pt;line-height:115%">) but do not
know how to make it work! I would really appreciate it if
you could give me hand in this regard.</span></p>
<p class="MsoNormal"><span
style="font-size:12pt;line-height:115%;font-family:'Times
New Roman',serif" lang="EN-US">Looking forward to hearing
from you soon.</span></p>
<p class="MsoNormal"><span
style="font-size:12pt;line-height:115%;font-family:'Times
New Roman',serif" lang="EN-US"><br>
</span></p>
<p class="MsoNormal"><span
style="font-size:12pt;line-height:115%;font-family:'Times
New Roman',serif" lang="EN-US">Regards,</span></p>
<div><br>
</div>
-- <br>
<div dir="ltr">
<div><b style="font-family:'times new roman',serif"><font>Ali
shirazi</font></b><br>
</div>
<div>
<div>
<div><font face="times new roman, serif"><span
style="color:rgb(32,32,32);border-collapse:collapse"><font
size="1">PhD Candidate</font></span></font></div>
</div>
<div><font face="times new roman, serif" size="1"><span
style="color:rgb(32,32,32);border-collapse:collapse"><font
color="#000000">School of Mechanical and
Manufacturing Engineering</font></span><br>
The University of New South Wales<br>
Sydney NSW 2052</font></div>
<div><font face="times new roman, serif" size="1">Australia</font></div>
<div><font face="times new roman, serif" size="1">Email:</font></div>
<div><font color="#0b5394" face="times new roman, serif"
size="1">
<a moz-do-not-send="true"
href="mailto:ali.shirazee@gmail.com" target="_blank">ali.shirazee@gmail.com</a></font></div>
<div><font face="times new roman, serif" size="1"><a
moz-do-not-send="true"
href="mailto:a.shirazi@student.unsw.edu.au"
target="_blank">a.shirazi@student.unsw.edu.au</a></font></div>
</div>
</div>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<br>
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</pre>
</blockquote>
<br>
<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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