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<p>Hi Weiwei,</p>
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<p>I had a look at your fitting equation and TRNSYS project.</p>
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<p>Firstly, you can adequately describe that data with a 2-parameter (linear) curve. The R^2 value does not improve by adding the third parameter. That will simplify things a bit.</p>
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</p>
<p>Second, your power coefficients are not quite right. In your excel spreadsheet, you haven't divided your power drawn by the pump by the nominal/rated power that corresponds to the rated mass flow rate of the pump. The power coefficients (a0,a1...) relate
to the relationship between P/P_rated and m/m_rated. Your coefficients should be more in the order of 0.4.</p>
<p><br>
</p>
<p>The error in your TRNSYS project is you have connected the outlet fluid temperature of the pump to the equation, instead of power consumption. Once you fix that, the power output should come out right, in the range 15-20kW.</p>
<p></p>
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<div><span style="font-size:10pt">Kind regards,</span></div>
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<div><span style="font-size:10pt"><b>Alastair McDowell</b></span></div>
<div><span style="font-size:10pt">Engineering Consultant</span><br>
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<div><span style="font-size:10pt"><strong>Energy Analysis & Engineering</strong> – Enabling innovation for a sustainable future</span></div>
<div><span style="font-size:10pt">T: +61 450 600 842</span></div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> TRNSYS-users <trnsys-users-bounces@lists.onebuilding.org> on behalf of 吴伟伟v v <xiaoweiweiwu@hotmail.com><br>
<b>Sent:</b> Tuesday, 17 November 2015 8:51 PM<br>
<b>To:</b> trnsys-users@lists.onebuilding.org<br>
<b>Subject:</b> Re: [TRNSYS-users] Type743’s power coefficients parameter setting</font>
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<h1><span lang="EN-US" style="font-size:12.0pt; font-weight:normal">Dear Alastair,</span></h1>
<h1><span lang="EN-US" style="font-size:12.0pt; font-weight:normal">Thank you for your patient reply. Now I can understand the relationship between the coefficients and the parameters. And, I tried to understood the Fortran code although my poor knowledge about
it.</span></h1>
<h1><span lang="EN-US" style="font-size:12.0pt; font-weight:normal">But it sees that the pump’s power drawn result is not right according to the setting as the following, Which is much lower than the equation curve I have attached the simple project(.tpf and.txt
file) and the fitting equation(.xls) data file. </span></h1>
<h1><span lang="EN-US" style="font-size:12.0pt; font-weight:normal"> </span></h1>
<h1><span lang="EN-US" style="font-size:12.0pt; font-weight:normal">For example, I has fitted a pump power curve equation as followings</span></h1>
<h1><span lang="EN-US" style="font-size:12.0pt">p = 56877 + 49714(m/m <sub>rated</sub>) + 1094.3(m/m
<sub>rated</sub>) ^2 (R² = 0.9959), So the setting is :</span></h1>
<p style="line-height:17.25pt"><span lang="EN-US" style="font-family:Calibri,sans-serif">power coefficient-1 = a0=56877 (Parameter 6 for TYPE 743)</span></p>
<p style="line-height:17.25pt"><span lang="EN-US" style="font-family:Calibri,sans-serif">power coefficient-2 = a1=49714 (Parameter 7 for TYPE 743)</span></p>
<p style="line-height:17.25pt"><span lang="EN-US" style="font-family:Calibri,sans-serif">power coefficient-3 = a2=1094.3(Parameter 8 for TYPE 743)</span></p>
<h1><span lang="EN-US" style="font-size:12.0pt; font-weight:normal"> May you tell me the reason? Thank you very much for your time!</span></h1>
<div><span lang="EN-US" style="font-size:12.0pt; font-weight:normal">with best regards</span></div>
<div><span lang="EN-US" style="font-size:12.0pt; font-weight:normal"><br>
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<div><span lang="EN-US" style="font-size:12.0pt; font-weight:normal">yours sincerely</span></div>
<div><span lang="EN-US" style="font-size:12.0pt; font-weight:normal">Weiwei</span></div>
<div>Chongqing University</div>
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From: xiaoweiweiwu@hotmail.com<br>
To: trnsys-users@lists.onebuilding.org<br>
Subject: Type743’s power coefficients parameter setting<br>
Date: Mon, 16 Nov 2015 13:49:52 +0800<br>
<br>
<div dir="ltr"><font size="3">Dear all, </font>
<h1><span style="font-weight:normal"><font size="3">In the type743’s document, there is an equation743.1 about P, which is power drawn the pump, as following:</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">P=a0+a1(m/mrated)+ a2(m/mrated)2+ a3(m/mrated)3+………..</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">In the type743’s parameter setting, parameter number 5 is set to“number of power coefficients”,if I input “3”then the parameter number6、7 、8 is as following：</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">power coefficient-1</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">power coefficient-2</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">power coefficient-3</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">And the explanation about the coefficient is “The value of the polynomial multiplier for the relationship between normalized pump power and normalized pump flow rate”.</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">My question is:</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">1)whether a1、a2 a3 is correspond to power coefficient-1、power coefficient-2 and power coefficient-3 respectively? if yes, how to set the value </font></span><span style="font-size:12pt; font-weight:normal">a0?
or i just need fitting an equation that </span><span style="font-size:12pt; font-weight:normal">a0 is zero?</span></h1>
<h1><span style="font-weight:normal"><font size="3">2)If not ,what is the right relationship between them?</font></span></h1>
<h1><span style="font-weight:normal"><font size="3">In addition, I referred to an example named “pumps with flow rate known” in Tess models of TRNSYS software, the type743’s parameter 5 is set to 3, and the parameter6 and 7 (power coefficient-1、power coefficient-2)
are both 0, while parameter 8 is set to 1. The similar situation setting could be found in other types such as TYPE510’s power coefficient.</font></span></h1>
<div><span lang="EN-US" style="font-family:Calibri,sans-serif"><font size="3">Thank you very much help me out of this issue.</font></span></div>
<div><span lang="EN-US" style="font-family:Calibri,sans-serif"><font size="3"><br>
</font></span></div>
<div><span lang="EN-US" style="font-family:Calibri,sans-serif"><font size="3">With best regards</font></span></div>
<div><span lang="EN-US" style="font-family:Calibri,sans-serif"><font size="3"><br>
</font></span></div>
<div><span lang="EN-US" style="font-family:Calibri,sans-serif"><font size="3">Yours sinscerely</font></span></div>
<div><span style="font-size:12pt; font-family:Calibri,sans-serif">Weiwei</span></div>
<div><span lang="EN-US" style="font-family:Calibri,sans-serif"><font size="3"><br>
</font></span></div>
<div><span lang="EN-US" style="font-family:Calibri,sans-serif"><font size="3">Chongqing university</font></span></div>
<div><span lang="EN-US" style="font-family:Calibri,sans-serif"><font size="3"><br>
</font></span></div>
<h1><span style="font-size:19px; font-weight:normal"><br>
</span></h1>
<h1><span style="font-size:19px; font-weight:normal"> </span></h1>
<h1><span style="font-size:19px; font-weight:normal"><br>
</span></h1>
<h1><span style="font-size:19px; font-weight:normal">Thank you very much help me out of this issue. </span></h1>
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