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<p class=MsoNormal><span style='color:black'>Assuming an approximate conversion
at 746 W per BHP – numerator, which is divided by some motor efficiency
corrections (all the logarithmic stuff) to get your </span><i>Pfan</i><span
style='color:black'> in Watts.<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:black'>For instance with 50 BHP, your
numbers might give you something similar to: 746 / 0.929 </span><span
style='font-family:"Arial","sans-serif";color:black'>x</span><span
style='color:black'> 50 = </span><i>Pfan </i>= 40.2 kW<span style='color:black'><o:p></o:p></span></p>
<p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:black'>David<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> BLDG-SIM@gard.com
[mailto:BLDG-SIM@gard.com] <b>On Behalf Of </b>Vikram Sami<br>
<b>Sent:</b> Thursday, July 05, 2007 3:12 PM<br>
<b>To:</b> BLDG-SIM@gard.com<br>
<b>Subject:</b> [BLDG-SIM] Question about Fan Power<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>So I'm
trying to calculate fan power, and came across this mindbender</span> <o:p></o:p></p>
<p><i>Pfan</i> = 746 / (1 - e[ -0.2437839 × ln( bhp ) - 1.685541 ])<b><u> <span
style='color:red'>× bhp</span></u></b> <o:p></o:p></p>
<p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Having done
the hard part (I figured out how to automate the process in XL with just the
CFM input using the natural log function ), I have only one question - does the
bhp (highlighted at the end) go in the numerator or denominator of the
equation?</span><o:p></o:p></p>
<p><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>i.e. -
Should the equation read</span> <o:p></o:p></p>
<p><i>Pfan</i> = 746 / [(1 - e[ -0.2437839 × ln( bhp ) - 1.685541 ]) × bhp] <o:p></o:p></p>
<p>Or <o:p></o:p></p>
<p><i>Pfan</i> = [746 / (1 - e[ -0.2437839 × ln( bhp ) - 1.685541 ])] × bhp <o:p></o:p></p>
<pre><o:p> </o:p></pre></div>
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