<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 (deltaTH=10 and delta TL= 2) is satisfied. I am attaching the excel file and issue is highlighted in this file (sheet 1). Also TRNSYS file is attached>
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 both 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.
Jeff
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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
On 10/25/2013 4:33 am, Adeel Waqas wrote:
Dear Trnsys users
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.
Issue is i have connected the "upper Input temperature" as collector outlet and "lower Input temperature" as outlet from storage tank heat exchanger.
I have set the deltaTH=10 and delta TL= 2 as i want that controller switch keep the pump on between this two limits.
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 (deltaTH=10 and delta TL= 2) is satisfied. I am attaching the excel file and issue is highlighted in this file (sheet 1). Also TRNSYS file is attached
I will be thanks for the help and the suggestion and to know where I am wrong.
Regards