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<p><<span style="font-size: 12pt;">But when u exported the TRNSyS data to excel to check the result it is noticed that sometimes pump is off even the above mentioned limit (deltaT<sub>H</sub>=10 and delta T<sub>L</sub>= 2) is satisfied. I am attaching the excel file and issue is highlighted in this file (sheet 1). Also TRNSYS file is attached></span></p>
<p>You're not doing anything wrong. There are times when your chosen deadbands aren't physically possible. Imagine a single solar collector with a huge pump attached to it. When the pump is off, the collector temperature is much higher than the tank during a sunny period and the pump is turned on. However, with the pump on the collector temperature is only 1 degree hotter than the tank due to the large flow rate - so the pump turns off. Which solution is correct? They b<span style="font-size: 12pt;"></span>oth are. In situations like this, TRNSYS will iterate for a while and finally "lock" the solution to one of the states. That's what you're seeing in your results.</p>
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<p>Jeff</p>
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<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>
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<p>On 10/25/2013 4:33 am, Adeel Waqas wrote:</p>
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<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;">Dear Trnsys users</span><span style="font-size: 12pt;"></span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;"> </span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;">I facing problem while using controller Type 2b between solar water heater and storage tank. i have spent several hours in understanding its behavior but still i am confused. </span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;">Issue is i have connected the <strong><span style="text-decoration: underline;">"upper Input temperature"</span></strong> as collector outlet and <strong><span style="text-decoration: underline;">"lower Input temperature"</span></strong> as outlet from storage tank heat exchanger.</span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;">I have set the <strong>deltaT<sub>H</sub>=10</strong> and <strong>delta T<sub>L</sub>= 2</strong> as i want that controller switch keep the pump on between this two limits.</span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;"> </span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;">But when u exported the TRNSyS data to excel to check the result it is noticed that sometimes pump is off even the above mentioned limit (deltaT<sub>H</sub>=10 and delta T<sub>L</sub>= 2) is satisfied. I am attaching the excel file and issue is highlighted in this file (sheet 1). Also TRNSYS file is attached</span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;"> </span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;">I will be thanks for the help and the suggestion and to know where I am wrong.</span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; font-family: arial,sans-serif; font-size: 13px; text-align: justify;"><span style="font-size: 12pt;"> </span></p>
<p class="MsoNormal" style="margin-bottom: 0.0001pt; text-align: justify;"><span style="font-family: Times New Roman,serif; font-size: small;">Regards</span></p>
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