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<p>Janeet,</p>
<p>Each of the collectors you specified has a gross area of 5.24 square meters - so with a total area of 42 square meters that means you have 8 collectors. How can you have a string of 5 collectors in series with 8 collectors? In series means that the same molecule of water flows through 5 collector modules one right after each other.</p>
<p>You chose efficiency mode 2 - which means your efficiency equation is based on Tave-Tamb. But the SRCC document clearly lists the efficiency as Tin-Tamb. Change your efficiency mode to 1.</p>
<p><Assuming TRNSYS uses gross areas and average temperatures.></p>
<p>Not sure what that means. And don't assume - verify. The TRNSYS efficiency equation can use of three modes; inlet, average or outlet and you need to set this correctly. As for gross area - the model wants the area consistent with the efficiency equation. So if your efficiency is based on gross area then gross area should be used.</p>
<p>If you have access to the TESS Libraries I strongly suggest you use Type 538 for the evacuated tube model. It's a significant upgrade over Type 71.</p>
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<p>Did you create an external data file for the IAM's based on the published data from the certification? Or did you just use a default external file?</p>
<p> </p>
<p>Jeff</p>
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<pre>---<br />Jeff Thornton
President - TESS LLC
3 N. Pinckney Street, Suite 202, Madison WI USA 53703
Office: (608) 274-2577 Fax: (608) 278-1475
www.tess-inc.com
E-Mail: thornton@tess-inc.com
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<p>On 07/15/2020 11:25 pm, janeet anand via TRNSYS-users wrote:</p>
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<div dir="ltr">Dear Experts,
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<div>Currently working on a project to simulate an absorption chiller fed from a solar collector.</div>
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<div>For the solar collector I am using type 71(ETC) of 42m2 collector area. Also attached the SRCC test certificate for the same. Problem is I am getting unacceptable high Outlet fluid temperatures eg. Tin=60 Tou=150 @ flow rate=250. Same is the case if I use test data from the Keymark test and further the outputs do not match with the outputs for the SRCC data.</div>
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<div>Please could you advise if the parameters are specified correctly and the assumptions mentioned are in line with what is required by TRNSYS. Assuming TRNSYS uses gross areas and average temperatures.</div>
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<div>1. <strong>Number in series</strong> <em>5</em> - <span style="color: #e06666;">(Solar array design calculated for required flow and outlet temp) </span> <br />2. <strong>Collector area</strong> <em>42 m^2</em> <span style="color: #e06666;">(Total gross collector array area, Trnsys will internally calculate nos in parallel)</span><span style="color: #ea9999;"> </span> <br />3. <strong>Fluid specific heat</strong> <em>4.190 kJ/kg.K</em> <span style="color: #e06666;">(water)</span><br />4. <strong>Efficiency mode</strong> <em>2</em> - <span style="color: #e06666;">(Tavg based on SRCC ISO efficiency equation note (P)=Ti-Ta)</span><br />5. <strong>Flow rate at test conditions</strong> <em>71.64 kg/hr.m^2</em> <span style="color: #e06666;">(SRCC Test mass flow rate .0199*3600-assumption is it is based on gross area and not aperture area )</span><br />6. <strong>Intercept efficiency</strong><em> 0.398</em> - <span style="color: #e06666;">(SRCC ISO eff. equation- SI units η= 0.398 - 0.62210(P/G) - 0.01611(P²/G). However solar keymark test data mentions 0.734)</span><br />7. <strong>Negative of first order efficiency coefficient</strong> <em>2.24 kJ/hr.m^2.K</em> <span style="color: #e06666;">(SRCC .6221*3.6. However, solar keymar test data mentions 5.5044 )</span><br />8. <strong>Negative of second order efficiency coefficient</strong> <em>0.058</em> kJ/hr.m^2.K^2 <span style="color: #e06666;">(SRCC .01611*3.6. However, solar keymark test data mentions 0.0166 ) </span><br />9. <strong>Logical unit of file containing biaxial IAM data</strong> <em>37</em> - <span style="color: #e06666;">(TRNSYS assigned)</span><br />10. <strong>Number of longitudinal angles for which IAMs are provided</strong> <em>11</em> - <span style="color: #e06666;">(external data file prepared as per SRCC data)</span><br />11. <strong>Number of transverse angles for which IAMs are provided</strong> <em>11</em> - <span style="color: #e06666;">(external data file prepared as per SRCC data)</span> </div>
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<div>Thank you for your time in advance.</div>
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<div>Regards,</div>
<div>Janeet</div>
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