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<p>Dear Weiwei,</p>
<p><br>
</p>
<p>power coefficient-1 = a0</p>
<p><span style="font-family: Calibri, Arial, Helvetica, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', NotoColorEmoji, 'Segoe UI Symbol', 'Android Emoji', EmojiSymbols; font-size: 16px;">power coefficient-2 = a1</span><br>
</p>
<p><span style="font-family: Calibri, Arial, Helvetica, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', NotoColorEmoji, 'Segoe UI Symbol', 'Android Emoji', EmojiSymbols; font-size: 16px;"><span style="font-family: Calibri, Arial, Helvetica, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', NotoColorEmoji, 'Segoe UI Symbol', 'Android Emoji', EmojiSymbols; font-size: 16px;">power
coefficient-3 = a2</span><br>
</span></p>
<p>...and so on.</p>
<p><br>
</p>
<p>You can verify this yourself by going into the Fortran code (available in C:\TRNSYS17\Tess Models\SourceCode\Type743.f90), you will find this code snippet:</p>
<p><br>
</p>
<p></p>
<div><span style="font-family: 'Courier New', monospace;">! Calculate the power multiplier</span></div>
<div><span style="font-family: 'Courier New', monospace;"> If (frac_rated_flow > 0.) Then</span></div>
<div><span style="font-family: 'Courier New', monospace;"> y_power = 0.</span></div>
<div><span style="font-family: 'Courier New', monospace;"> Do j = 1,n_coeffs</span></div>
<div><span style="font-family: 'Courier New', monospace;"> <span style="background-color: rgb(255, 255, 0);">
y_power = y_power+y(j)*(frac_rated_flow**DBLE(j-1))</span></span></div>
<div><span style="font-family: 'Courier New', monospace;"> EndDo</span></div>
<div><span style="font-family: 'Courier New', monospace;"> Else</span></div>
<div><span style="font-family: 'Courier New', monospace;"> y_power = 0.</span></div>
<div><span style="font-family: 'Courier New', monospace;"> EndIf</span></div>
<br>
<p></p>
<p>This shows that the first power coefficient (y(1)) has an exponent of zero (shown by
<span style="font-family: 'Courier New', monospace;">DBLE(j-1)</span>).<br>
</p>
<p><br>
</p>
<p>To your second question, the example where a0=a1=0, a2=1, this refers to a power equation: P/P_rated = (m/mrated)^2.<br>
</p>
<p><br>
</p>
<p>I hope this solves your questions.<br>
</p>
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<div><span style="font-size:10pt">Kind regards,</span></div>
<div><span style="font-size:10pt"><br>
</span></div>
<div><span style="font-size:10pt"><b>Alastair McDowell</b></span></div>
<div><span style="font-size:10pt">Engineering Consultant</span><br>
</div>
<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>
<div><span style="font-size:10pt">E: alastair.mcdowell@energyae.com</span></div>
<div><span style="font-size:10pt">608 Harris St Sydney NSW 2007 Australia | </span><span style="font-size:10pt"><a href="http://www.energyae.com/" target="_blank" id="LPNoLP">http://www.energyae.com</a></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> Monday, 16 November 2015 4:49 PM<br>
<b>To:</b> trnsys-users@lists.onebuilding.org<br>
<b>Subject:</b> [TRNSYS-users] Type743’s power coefficients parameter setting</font>
<div> </div>
</div>
<div>
<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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