<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">Gavin,<DIV>If you input 250,000 CFM at the equipment level and let zones auto size a few things could happen. If the fan is larger than the sum of the zone design airflows (diversified or undiversified) then the fan will always operate at part load. Depending on the part load curve you have assumed and the actual method of fan speed control you could have dramatically different part load performance (% power as a function of % flow) - check both of these things.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Also DOE-2 allows you to input a kW/CFM or an efficiency combined with the pressure and flow. Even the best backward curved airfoil fans may only achieve a wire to air efficiency of 67% - Fan total efficiency of 80%, belt drive / sheave efficiency 95%, VSD drive efficiency of 96%, motor efficiency of 92%. And keep in mind this is applied to total pressure not static - static wire-air efficiency will be lower by the ratio of static to total pressure. More standard Air Handlers probably have a wire to air efficiency of 55% or less.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Also don't underestimate duct leakage or damper leakage if the system is an existing high pressure system.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Regards,</DIV><DIV>Graham<BR><DIV><DIV>On 10/11/2007, at 3:03 AM, Gavin Gui wrote:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><SPAN class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Arial; font-size: 16px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><DIV class="Section1"><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">Jim,</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><O:P style="font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; "> </SPAN></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">The fan static pressure has been set to the maximum of 8.0 WG (any higher and the model will not run) despite the equipment schedule is stated as 10 WG.</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><O:P style="font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; "> </SPAN></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">As for the CFM, it is input at 250,000 cfm (according to the equipment data).</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><O:P style="font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; "> </SPAN></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">As for logger inaccuracy, we logged both supply fans and they checked out against one another.</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><O:P style="font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; "> </SPAN></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">I have tried looking at all the parameters in the simulation that might affect the vent fans energy and demand, including operating schedules, but were unable to find any that might justify the differences.</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><O:P style="font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; "> </SPAN></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><O:P style="font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; "> </SPAN></O:P></SPAN></FONT></P><DIV><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">With regards</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">Gavin Gui</SPAN></SPAN></FONT><FONT size="2"><SPAN style="font-size: 10.0pt; font-family: Times New Roman; font-size: 13.3333px; "><O:P style="font-family: Times New Roman; font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Times New Roman"><SPAN style="font-size: 10.0pt; font-family: Times New Roman; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Times New Roman; font-size: 13.3333px; "> </SPAN></SPAN></FONT><FONT size="2"><SPAN style="font-size:10.0pt; font-family: Times New Roman; font-size: 13.3333px; "><O:P style="font-family: Times New Roman; font-size: 13.3333px; "></O:P></SPAN></FONT></P></DIV><DIV><DIV class="MsoNormal" align="center" style="text-align:center; font-family: Times New Roman; "><FONT size="3" face="Times New Roman"><SPAN style="font-size:12.0pt; font-family: Times New Roman; text-align: center; "><SPAN class="Apple-style-span" style="font-family: Times New Roman; text-align: center; "></SPAN><HR size="2" width="100%" align="center" tabindex="-1"></SPAN></FONT></DIV><P class="MsoNormal"><B style="font-family: Times New Roman; font-weight: bold; "><FONT size="2" face="Tahoma"><SPAN style="font-size:10.0pt; font-family:Tahoma;font-weight:bold; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">From:</SPAN></SPAN></FONT></B><FONT size="2" face="Tahoma"><SPAN style="font-size:10.0pt;font-family:Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; "> Zarske, Jim [<A href="mailto:jzarske@nexant.com">mailto:jzarske@nexant.com</A>] </SPAN><BR style="font-family: Tahoma; font-size: 13.3333px; "><B style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; "><SPAN style="font-weight:bold; font-family: Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">Sent:</SPAN></SPAN></B><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; "> Friday, November 09, 2007 10:52 AM</SPAN><BR style="font-family: Tahoma; font-size: 13.3333px; "><B style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; "><SPAN style="font-weight:bold; font-family: Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">To:</SPAN></SPAN></B><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; "> Gavin Gui</SPAN><BR style="font-family: Tahoma; font-size: 13.3333px; "><B style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; "><SPAN style="font-weight:bold; font-family: Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">Subject:</SPAN></SPAN></B><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; "> RE: [BLDG-SIM] Ventilation Fans</SPAN></SPAN></FONT><O:P style="font-family: Times New Roman; "></O:P></P></DIV><P class="MsoNormal"><FONT size="3" face="Times New Roman"><SPAN style="font-size: 12.0pt; font-family: Times New Roman; "><O:P style="font-family: Times New Roman; "><SPAN class="Apple-style-span" style="font-family: Times New Roman; "> </SPAN></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" color="blue" face="Arial"><SPAN style="font-size: 10.0pt;font-family:Arial;color:blue; color: rgb(0, 0, 255); font-size: 13.3333px; "><SPAN class="Apple-style-span" style="color: rgb(0, 0, 255); font-size: 13.3333px; ">It sounds like you need increase the fan static pressure or kW/CFM in eQUEST (you stated these are high pressure fans, so I assume the power use is higher than a typical fan), confirm you have the correct CFM inputted into the model, or double check the accuracy of the logger data.</SPAN></SPAN></FONT><O:P style="font-family: Times New Roman; "></O:P></P><P class="MsoNormal"><FONT size="3" face="Times New Roman"><SPAN style="font-size: 12.0pt; font-family: Times New Roman; "><SPAN class="Apple-style-span" style="font-family: Times New Roman; "> </SPAN><O:P style="font-family: Times New Roman; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" color="blue" face="Arial"><SPAN style="font-size: 10.0pt;font-family:Arial;color:blue; color: rgb(0, 0, 255); font-size: 13.3333px; "><SPAN class="Apple-style-span" style="color: rgb(0, 0, 255); font-size: 13.3333px; ">Jim</SPAN></SPAN></FONT><O:P style="font-family: Times New Roman; "></O:P></P><P class="MsoNormal"><FONT size="3" face="Times New Roman"><SPAN style="font-size: 12.0pt; font-family: Times New Roman; "><O:P style="font-family: Times New Roman; "><SPAN class="Apple-style-span" style="font-family: Times New Roman; "> </SPAN></O:P></SPAN></FONT></P><DIV class="MsoNormal" align="center" style="text-align:center; font-family: Times New Roman; "><FONT size="3" face="Times New Roman"><SPAN style="font-size:12.0pt; font-family: Times New Roman; text-align: center; "><SPAN class="Apple-style-span" style="font-family: Times New Roman; text-align: center; "></SPAN><HR size="2" width="100%" align="center" tabindex="-1"></SPAN></FONT></DIV><P class="MsoNormal" style="margin-bottom:12.0pt; font-family: Times New Roman; "><B style="font-family: Times New Roman; font-weight: bold; "><FONT size="2" face="Tahoma"><SPAN style="font-size:10.0pt;font-family:Tahoma;font-weight:bold; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">From:</SPAN></SPAN></FONT></B><FONT size="2" face="Tahoma"><SPAN style="font-size:10.0pt;font-family:Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; "> BLDG-SIM@gard.com [<A href="mailto:BLDG-SIM@gard.com">mailto:BLDG-SIM@gard.com</A>] </SPAN><B style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; "><SPAN style="font-weight:bold; font-family: Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">On Behalf Of </SPAN></SPAN></B><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; ">Gavin Gui</SPAN><BR style="font-family: Tahoma; font-size: 13.3333px; "><B style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; "><SPAN style="font-weight:bold; font-family: Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">Sent:</SPAN></SPAN></B><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; "> Friday, November 09, 2007 8:03 AM</SPAN><BR style="font-family: Tahoma; font-size: 13.3333px; "><B style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; "><SPAN style="font-weight:bold; font-family: Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">To:</SPAN></SPAN></B><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; "> <A href="mailto:BLDG-SIM@gard.com">BLDG-SIM@gard.com</A></SPAN><BR style="font-family: Tahoma; font-size: 13.3333px; "><B style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; "><SPAN style="font-weight:bold; font-family: Tahoma; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; font-weight: bold; ">Subject:</SPAN></SPAN></B><SPAN class="Apple-style-span" style="font-family: Tahoma; font-size: 13.3333px; "> [BLDG-SIM] Ventilation Fans</SPAN></SPAN></FONT><O:P style="font-family: Times New Roman; "></O:P></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">Hi, I am using eQuest to simulate a mid-rise commercial building. The HVAC system is a simple setup whereby huge axial vane supply fans provide 55F cold air, under high pressure, to the VAV boxes located at the respective floors. The air is returned via ducts using similar fans located near the system. However the modeled results obtained for the vent fans electric demand and consumption differ greatly from the logged data obtained from the site. The actual data shows about 75% higher than the model results, both in demand and consumption.</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><O:P style="font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; "> </SPAN></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">I would greatly appreciate if anyone can advise me on where the problem is or if there is any way I can fine tune the model to be closer to the actual data. Thank you.</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><O:P style="font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; "> </SPAN></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="2" face="Arial"><SPAN style="font-size:10.0pt; font-family:Arial; font-size: 13.3333px; "><SPAN class="Apple-style-span" style="font-size: 13.3333px; ">With regards,</SPAN><O:P style="font-size: 13.3333px; "></O:P></SPAN></FONT></P><P class="MsoNormal"><FONT size="3" face="Arial"><SPAN style="font-size:12.0pt; font-family:Arial">Gavin Gui</SPAN></FONT><O:P style="font-family: Times New Roman; "></O:P></P><P class="MsoNormal"><FONT size="3" face="Times New Roman"><SPAN style="font-size: 12.0pt; font-family: Times New Roman; "><O:P style="font-family: Times New Roman; "><SPAN class="Apple-style-span" style="font-family: Times New Roman; "> </SPAN></O:P></SPAN></FONT></P><PRE style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "><FONT size="2" face="Courier New"><SPAN style="font-size:10.0pt; font-family: Courier New; font-size: 13.3333px; white-space: pre; "><O:P style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "><SPAN class="Apple-style-span" style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "> </SPAN></O:P></SPAN></FONT></PRE><PRE style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "><FONT size="2" face="Courier New"><SPAN style="font-size:10.0pt; font-family: Courier New; font-size: 13.3333px; white-space: pre; "><SPAN class="Apple-style-span" style="font-family: Courier New; font-size: 13.3333px; white-space: pre; ">==================</SPAN><O:P style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "></O:P></SPAN></FONT></PRE><PRE style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "><FONT size="2" face="Courier New"><SPAN style="font-size:10.0pt; font-family: Courier New; font-size: 13.3333px; white-space: pre; "><SPAN class="Apple-style-span" style="font-family: Courier New; font-size: 13.3333px; white-space: pre; ">You received this e-mail because you are subscribed </SPAN><O:P style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "></O:P></SPAN></FONT></PRE><PRE style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "><FONT size="2" face="Courier New"><SPAN style="font-size:10.0pt; font-family: Courier New; font-size: 13.3333px; white-space: pre; "><SPAN class="Apple-style-span" style="font-family: Courier New; font-size: 13.3333px; white-space: pre; ">to the <A href="mailto:BLDG-SIM@GARD.COM">BLDG-SIM@GARD.COM</A> mailing list. To unsubscribe </SPAN><O:P style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "></O:P></SPAN></FONT></PRE><PRE style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "><FONT size="2" face="Courier New"><SPAN style="font-size:10.0pt; font-family: Courier New; font-size: 13.3333px; white-space: pre; "><SPAN class="Apple-style-span" style="font-family: Courier New; font-size: 13.3333px; white-space: pre; ">from this mailing list send a blank message to </SPAN><O:P style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "></O:P></SPAN></FONT></PRE><PRE style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "><FONT size="2" face="Courier New"><SPAN style="font-size:10.0pt; font-family: Courier New; font-size: 13.3333px; white-space: pre; "><SPAN class="Apple-style-span" style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "><A href="mailto:BLDG-SIM-UNSUBSCRIBE@GARD.COM">BLDG-SIM-UNSUBSCRIBE@GARD.COM</A></SPAN><O:P style="font-family: Courier New; font-size: 13.3333px; white-space: pre; "></O:P></SPAN></FONT></PRE></DIV><PRE style="font-family: Courier New; font-size: 13.3333px; white-space: pre; ">======================================================
You received this e-mail because you are subscribed
to the <A href="mailto:BLDG-SIM@GARD.COM">BLDG-SIM@GARD.COM</A> mailing list. To unsubscribe
from this mailing list send a blank message to
<A href="mailto:BLDG-SIM-UNSUBSCRIBE@GARD.COM">BLDG-SIM-UNSUBSCRIBE@GARD.COM</A>
</PRE><BR class="Apple-interchange-newline"></SPAN></BLOCKQUOTE></DIV><BR></DIV></BODY></HTML>