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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Mike Rosenberg’s section is a welcome improvement but it is still a challenging aspect.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>You could be proportioning power (kW) across fans with different operation. For example: <o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>CAV exhaust fan vs. VFD driven supply & return fans<o:p></o:p></span></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span></span><![endif]><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>“Powered exhaust” fans that only operate to provide relief during economizer mode vs. normal supply fans<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>In some instances, applying a bit of professional judgment will get better results in terms of fan energy (kWh) and fan heat (DT and resultant heating and cooling loads).<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> <o:p></o:p></span></p><div><p class=MsoNormal style='text-autospace:none'><b><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#5F574F'>Paul Riemer, PE, LEED AP</span></b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> <o:p></o:p></span></p><p class=MsoNormal><b><span style='font-family:"Verdana","sans-serif";color:#C4262E'>DUNHAM</span></b><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#5F574F'><br>Celebrating 50 Years of Service</span><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#5F574F'><o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Andrew Craig<br><b>Sent:</b> Tuesday, March 15, 2011 4:24 PM<br><b>To:</b> James Hansen; bldg-sim@lists.onebuilding.org<br><b>Subject:</b> Re: [Bldg-sim] pro-rating fan power to supply/return fans per 90.1-2007?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>James---<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>This was discussed recently in the posts. See the attached response from last Tuesday. <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Mike Rosenberg commented that this is being addressed in the upcoming 90.1-2010 as such:<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b>G3.1.2.10.1 </b>The calculated system fan power shall be<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>distributed to supply, return, exhaust, and relief fans in the<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>same proportion as the proposed design.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Regards,<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><b>Andrew Craig PE, LEED AP<br></b>Project Mechanical Engineer<br><br><b>INTERFACE ENGINEERING<br>email </b><a href="mailto:andrewc@interfaceeng.com">andrewc@interfaceeng.com</a><br><b>direct </b>503.382.2696<br><br><b><a href="http://www.interfaceeng.com/">www.interfaceeng.com</a><br><br></b><o:p></o:p></p></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b>From:</b> bldg-sim-bounces@lists.onebuilding.org [mailto:bldg-sim-bounces@lists.onebuilding.org] <b>On Behalf Of </b>James Hansen<br><b>Sent:</b> Tuesday, March 15, 2011 12:05 PM<br><b>To:</b> bldg-sim@lists.onebuilding.org<br><b>Subject:</b> [Bldg-sim] pro-rating fan power to supply/return fans per 90.1-2007?<o:p></o:p></p></div></div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>App G says that if the proposed building has return fans, the baseline building is to be modeled with them as well, sized either at the minimum required to ensure ventilation, or 90% of the supply volume, whichever is greater. And the fan power calculations show that the KW allowance is for all supply, return, exhaust and relief fans combined. <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>How do you generally pro-rate the fan power between supply and return fans in the baseline model? Ultimately it probably doesn’t make too much difference, but is there an actual ruling that tells you how to do this?<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Thanks,<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b>GHT Limited<br><ns0:PersonName>James Hansen</ns0:PersonName>, PE, LEED AP<o:p></o:p></b></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b>Senior Associate<o:p></o:p></b></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><ns0:Street><ns0:address>1010 N. Glebe Rd, Suite 200</ns0:address></ns0:Street><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><ns0:place><ns0:City>Arlington</ns0:City>, <ns0:State>VA</ns0:State> <ns0:PostalCode>22201-4749</ns0:PostalCode></ns0:place><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>703-338-5754 (Cell)<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>703-243-1200 (Office)<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>703-276-1376 (Fax)<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="http://www.ghtltd.com/">www.ghtltd.com</a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><o:p> </o:p></b></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><o:p> </o:p></p></div></div></body></html>