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Dear Yeo,<br>
Jean's responses are all quite accurate. I wanted to add a little
bit to the discussion in the hopes that it might make your life a
little easier. Some years ago, we participated in a research project
in which we were looking at whether the performance of certain
pieces of HVAC equipment can effectively be normalized. In other
words you look at the COP and capacity of a device at a particular
combination of inlet conditions and then divide the COP and the
capacity by the rated COP and capacity for the device. Then you plot
the normalized performance over the entire operation range of the
equipment and you do the same for the same piece of equipment from
other manufacturers and of other rated capacities. It turns out that
some kinds of equipment (particularly single stage heat pumps and
both air and water cooled chillers) normalize very well meaning that
their normalized performance curves all look about the same.
Unloading (part load ratio) curves can look a bit different but they
begin to look similar again if you first sort them by compressor
type (screw, rotary, etc.). Other pieces of equipment do not look
the same at all if you normalize them (absorption chillers are a
good example). <br>
<br>
The lesson in all this is that if you have a specific chiller, it
is best to get the manufacturer's data for that chiller and to
create a data file from it. If, however, you just need a generic
chiller, you can use the default performance curves in the
\Trnsys17\Tess Models\SampleCatalogData\ directory and set the rated
capacity and COP parameters in the Type; you will be quite close in
your performance estimates.<br>
<br>
One other note; make sure that the rated capacity and COP that you
enter for parameters are at the same conditions to which the
external data file is normalized. In other words, if the data file
is normalized to a 5C oulet chilled water temperature and a 16C
inlet cooling water temperature then make sure that the capacity and
COP that you enter as the rated values are at those same conditions.
<br>
Best,<br>
David<br>
<br>
<br>
<div class="moz-cite-prefix">On 2/15/2013 07:10, Jean Marais wrote:<br>
</div>
<blockquote
cite="mid:CAAGg3bzeMafHHEArf5De+wJnNRmQW799SrHYSWCbgLSGCOsrOg@mail.gmail.com"
type="cite">Wow. You stated these questions so well that I can
only think that you did so already knowing the answeres.<br>
1. You can't. You need a comprehensive data set from your chiller
supplier, specifying a matrix of COPs at different water
temperatures on supply and return side as well as condenser supply
and return side.<br>
2. This will be clear in the data set. It is very possible.<br>
3. There is no mathematical thermal corrolation. It is chiller
dependant. It is a different data set.<br>
4. Yes. You'll need data at all the points where your chiller may
operate at. For example if you don't have data for the chiller
performance at less than 20% of full rated capacity, then the
simulation will issue a warning when your chiller model is
required to output results at these conditions (most chillers will
turn off below 20% demand).<br>
5. Correct.<br>
I stand corrected on any points.<br>
<br>
<div class="gmail_quote">On 15 February 2013 10:36, #YEO KEAT KEE#
<span dir="ltr"><<a moz-do-not-send="true"
href="mailto:YEOK0031@e.ntu.edu.sg" target="_blank">YEOK0031@e.ntu.edu.sg</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div link="blue" vlink="purple" lang="EN-SG">
<div>
<p class="MsoNormal"><span lang="EN-US">Dear Fellow Trnsys
Users</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">I am a new user to
Trnsys and is modeling a water cooled chiller system
using type 666 as the chiller. </span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">I understand that
if I want to model a specific chiller model in the
system, I will have to make changes to the chiller
performance data file and the part load performance
data file.
</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">In the chiller
performance data file, I see that there the capacity
ratio and the COP ratio being defined as 1 at 7C
Outlet CHWT 30C INLET CWT.
</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p><span lang="EN-US"><span>1.<span style="font:7.0pt
"Times New Roman"">
</span></span></span><span lang="EN-US">If I only
have the performance data of the chiller at 6.7C
Outlet CHWT 29.4C INLET CWT, how can I make use of
this data to input it into the chiller performance
data file?</span></p>
<p><span lang="EN-US"> </span></p>
<p><span lang="EN-US"><span>2.<span style="font:7.0pt
"Times New Roman"">
</span></span></span><span lang="EN-US">Must the
capacity ratio and the COP ratio being defined as 1 at
7C Outlet CHWT 30C INLET CWT, or can it be defined as
1 at other Outlet CHWT and Inlet CWT ?</span></p>
<p><span lang="EN-US"> </span></p>
<p><span lang="EN-US"><span>3.<span style="font:7.0pt
"Times New Roman"">
</span></span></span><span lang="EN-US">How does the
part load ratio data of the chiller relate to the
different Capacity Ratio and COP ratio ?</span></p>
<p><span lang="EN-US"> </span></p>
<p><span lang="EN-US"><span>4.<span style="font:7.0pt
"Times New Roman"">
</span></span></span><span lang="EN-US">In the
parameter tab of the type 666 chiller, it is stated
that “The capacity of the machine at its rated
condition (typically 30 C (85 F) inlet cooling water
temperature and 7 C (44 F) chilled water set point
temperature)The data file associated with this model
should be consistent with this rating conditions.” .
Does it mean that I have to include the chiller
performance at 7C chilled water set point and 30C
inlet cooling water temperature in the chiller
performance data file ?</span></p>
<p><span lang="EN-US"> </span></p>
<p><span lang="EN-US"><span>5.<span style="font:7.0pt
"Times New Roman"">
</span></span></span><span lang="EN-US">In the
chiller performance data file, it is observed that the
chiller capacity ratio can be more than 1. Does this
means that the chiller current capacity is higher than
the rated capacity?
</span></p>
<p><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">Can anyone kindly
advice on the above mentioned queries ?</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">Thank You !</span></p>
<p class="MsoNormal"><span lang="EN-US"> </span></p>
<p class="MsoNormal"><span lang="EN-US">Best Regards</span></p>
<p class="MsoNormal"><span lang="EN-US">KK Yeo</span></p>
<p><span lang="EN-US"> </span></p>
</div>
</div>
<br>
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</blockquote>
</div>
<br>
<br>
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<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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