<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN">
<html><body>
<p>Aditi,</p>
<p>Type 74 is a somewhat simple way of modeling a low temperature CPC. A more detailed model can be found in the TESS High Temperature Solar Library. The model there considers a time-varying loss coefficient as well as a more rigorous solution of the differential equations that result from the fluid properties changing with temperature. Using that model also requires that you use the accompanying storage tank model, pipes etc to also account for the property changes.</p>
<p>If the collector you are considering has been tested to the popular c1 to c6 coefficient approach, we also have models that can replicate that performance model.</p>
<p> </p>
<p>Jeff</p>
<p> </p>
<div>
<pre>---<br />Jeff Thornton
President - TESS LLC
22 N. Carroll Street, Madison WI USA 53703
Office: (608) 274-2577 Fax: (608) 278-1475
www.tess-inc.com
E-Mail: thornton@tess-inc.com
</pre>
</div>
<p>On 11/21/2017 6:13 am, Aditi Garg via TRNSYS-users wrote:</p>
<blockquote type="cite" style="padding-left:5px; border-left:#1010ff 2px solid; margin-left:5px"><!-- html ignored --><!-- head ignored --><!-- meta ignored -->
<div dir="ltr"><br clear="all" />
<div>
<div class="gmail_signature">
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div dir="ltr">
<div dir="ltr">
<div>
<div dir="ltr">
<div>Hello everyone,</div>
<div> </div>
<div>I was working on type 74 CPC. I tried checking the collector outlet temp. for a location and I got temperature up to 600 degree C which doesn`t seem so realistic. In parameters of TYPE 74, the overall loss coefficient U<span style="font-size: xx-small;">L <span style="font-size: small;">is fixed as 3kJ/hr.m2.K.</span></span></div>
<div><span style="font-size: xx-small;"><span style="font-size: small;"> </span></span></div>
<div><span style="font-size: xx-small;"><span style="font-size: small;">Now, </span></span><span style="font-size: xx-small;"><span style="font-size: small;">U<span style="font-size: xx-small;">L<span style="font-size: small;"> depends on ambient temperature, average collector fluid temperature and some other parameters as well.</span></span></span></span><span style="font-size: small;"> <br /></span></div>
<div><span style="font-size: small;"> </span></div>
<div><span style="font-size: small;"></span>So if these temperature are varying with time then the loss coefficient should also vary, which is not happening as I think. So is there any option through which we can modify the loss coefficient ( as a function of temperatures and other parameters) and get some realistic collector outlet temperatures.</div>
<div> </div>
<div> </div>
<div><span style="font-size: 12.8px;"><span style="color: #444444; font-family: arial, helvetica, sans-serif;"><strong> </strong></span></span></div>
<div><span style="font-size: 12.8px;"><span style="color: #999999; font-family: arial, helvetica, sans-serif;"><strong>Regards</strong></span></span></div>
<div><span style="color: #999999;"><strong style="font-family: arial,helvetica,sans-serif; font-size: 12.8px;">Aditi Garg</strong><br /></span></div>
</div>
<div dir="ltr">
<div style="font-size: 12.8px;">
<div><span style="color: #999999;"><strong style="font-size: 12.8px;">PhD Research Scholar</strong><br /></span></div>
</div>
<div style="font-size: 12.8px;"><strong><span style="color: #999999;">Department of Mechanical Engineering<br /></span></strong></div>
<span style="color: #999999;"><strong style="font-size: 12.8px;">Indian Institute </strong><strong style="font-size: 12.8px;">of Technology, Delhi</strong></span><span style="font-size: 12.8px;"><span style="color: #000000; font-family: arial, helvetica, sans-serif;"><strong><br /></strong></span></span>
<div><span style="color: #999999;"><span style="font-size: 12.8px;"><span style="font-family: arial, helvetica, sans-serif;"><strong>Hauz Khas,New Delhi-110016<br /></strong></span></span></span></div>
<div><span style="color: #999999;"><span style="font-size: 12.8px;"><span style="font-family: arial, helvetica, sans-serif;"><strong>India<br /></strong></span></span></span></div>
<div><span style="color: #999999;"><span style="font-size: 12.8px;"><span style="font-family: arial, helvetica, sans-serif;"><strong>Email ID: <a href="mailto:aditigarg107@gmail.com">aditigarg107@gmail.com</a><br /><br /><br /></strong></span></span></span></div>
</div>
<div dir="ltr"> </div>
</div>
<div dir="ltr"> </div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<br />
<pre>_______________________________________________
TRNSYS-users mailing list
<a href="mailto:TRNSYS-users@lists.onebuilding.org">TRNSYS-users@lists.onebuilding.org</a>
<a href="http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org</a>
</pre>
</blockquote>
</body></html>