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<p>Circulate water through the collector when there is little or no solar radiation and the inlet temperature is above the ambient temperature.</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 07/25/2012 4:26 pm, Richard Thygesen wrote:</p>
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<p class="MsoNormal"><span>Dear Trnsys users!<!-- o ignored --></span></p>
<p class="MsoNormal"><span>I wonder how it is possible to get a negative ”useful energy gain” from solar collector type 539 during some timesteps.<!-- o ignored --></span></p>
<p class="MsoNormal"><span>I have read the documentation without any success of finding the answer for this question.<!-- 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"><strong><span style="font-size: 9.0pt; font-family: 'Arial','sans-serif'; mso-fareast-language: SV;">Richard Thygesen<!-- o ignored --></span></strong></p>
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