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<p>Well if you look carefully at your plots, power is not "almost constant". Change the scale of the power plot and you'll see the spikes that you are observing in your COP. Have you spot-checked your performance map by running the chiller at "known conditions" and seeing that you're getting out of your model what you are expecting?</p>
<p> </p>
<p>Jeff</p>
<p> </p>
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<pre>---</pre>
<p>Jeff Thornton</p>
<p><em>President - TESS LLC</em></p>
<p><em>22 N. Carroll Street, Madison WI USA 53703</em></p>
<p><em>Office: (608) 274-2577 Fax: (608) 278-1475</em></p>
<p><em>www.tess-inc.com</em></p>
<p><em>E-Mail: thornton@tess-inc.com</em></p>
<p> </p>
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<p>On 03/26/2013 10:44 pm, #YEO KEAT KEE# wrote:</p>
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<p class="MsoNormal"><span>Dear Fellow Trnsys Users, <!-- o ignored --></span></p>
<p class="MsoNormal"><span><!-- o ignored --> </span></p>
<p class="MsoNormal"><span>I am running a parametric study using the TYPE 666 Chiller and I have some unexplainable observations with regards to the Chiller COP. <!-- o ignored --></span></p>
<p class="MsoNormal"><span><!-- o ignored --> </span></p>
<p class="MsoNormal"><span>It seems that the chiller COP has a lot of unexplainable spikes and fluctuations throughout the simulated year. <!-- o ignored --></span></p>
<p class="MsoNormal"><span><!-- o ignored --> </span></p>
<p class="MsoNormal"><span>This is observed despite <!-- o ignored --></span></p>
<p class="MsoListParagraph" style="text-indent: -18.0pt; mso-list: l0 level1 lfo2;"><span><span style="mso-list: Ignore;">1.<span style="font: 7.0pt 'Times New Roman';"> </span></span></span><span> An almost constant part load ratio (load) handled by the chiller. <!-- o ignored --></span></p>
<p class="MsoListParagraph" style="text-indent: -18.0pt; mso-list: l0 level1 lfo2;"><span><span style="mso-list: Ignore;">2.<span style="font: 7.0pt 'Times New Roman';"> </span></span></span><span>Entering Condenser Water Temperature to the chiller remains almost constant, with little fluctuations. <!-- o ignored --></span></p>
<p class="MsoListParagraph" style="text-indent: -18.0pt; mso-list: l0 level1 lfo2;"><span><span style="mso-list: Ignore;">3.<span style="font: 7.0pt 'Times New Roman';"> </span></span></span><span>Power consumed by the chiller remaining almost constant. <!-- o ignored --></span></p>
<p class="MsoNormal"><span><!-- o ignored --> </span></p>
<p class="MsoNormal"><span>I understand that in TRNSYS, COP=Qmet/P, if both the Qmet and P are relatively constant, what could be causing the spike observed in the COP ?<!-- o ignored --></span></p>
<p class="MsoNormal"><span><!-- o ignored --> </span></p>
<p class="MsoNormal"><span>I have attached some screen shots from the results of my simulation. <!-- o ignored --></span></p>
<p class="MsoNormal"><span><!-- o ignored --> </span></p>
<p class="MsoNormal"><span>Has anyone encountered the same situation before ? Or any advice on why this is happening ?<!-- o ignored --></span></p>
<p class="MsoNormal"><span><!-- o ignored --> </span></p>
<p class="MsoNormal"><span>Best Regards,<!-- o ignored --></span></p>
<p class="MsoNormal"><span>Yeo <!-- o ignored --></span></p>
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