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<p><I have a problem with the mass balances of my system. In my proct a flow diverter divides the waterflow into two separate pipes. .After the flowdiverter both pipes go to their own pumps. The flow diverter is controlled according to the ratio of mass flows produced by the pumps. After the pumps comes heating loads. After that the waterflows are connected in a flow mixer and the water is being heated in a heatpump. <br /><br />The problem is that Trnsys gives mass balance warnings for both pumps. When I check the mass flows of the pumps, they some times are even larger than the rated flow of the pump.I think the problem has something to do with the flow diverter...<br /><br />Can someone give me advice how to fix this problem and make the mass flows balanced. I have attached a demonstrative picture of my project.><br /><br /></p>
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<p>That's a very common system in TRNSYS and shouldn't be a problem. I'm guessing that the equation you use to set the diverter is wrong. Try something like:</p>
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<p>Y_Diverter=MIN(1,(Mpump1/MAX(0.001,(Mpump1+Mpump2))))</p>
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<p>Mpump1 is the flow rate from the first pump and Mpump2 is the flow rate from the second pump. Then connect Y_Diverter to the Type 11 flow diverter control signal input and then connect Outputs 1 and 2 from the flow diverter to Pump2 (critical) and Outputs 3 and 4 from the flow diverter to Pump1.</p>
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<p>Jeff</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>
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<p>On 09/19/2012 5:54 am, Santeri Siren wrote:</p>
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<p>Dear all,<br /><br />I have a problem with the mass balances of my system. In my proct a flow diverter divides the waterflow into two separate pipes. .After the flowdiverter both pipes go to their own pumps. The flow diverter is controlled according to the ratio of mass flows produced by the pumps. After the pumps comes heating loads. After that the waterflows are connected in a flow mixer and the water is being heated in a heatpump. <br /><br />The problem is that Trnsys gives mass balance warnings for both pumps. When I check the mass flows of the pumps, they some times are even larger than the rated flow of the pump.I think the problem has something to do with the flow diverter...<br /><br />Can someone give me advice how to fix this problem and make the mass flows balanced. I have attached a demonstrative picture of my project.<br /><br />best regards. <br />Santeri Siren</p>
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