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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'>If you’re looking to see what change in temp you have based on a length of duct, insulation, etc, check out:<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'><a href="http://www.mcgillairflow.com/textDocs/techTools/converted/thermalData1.php">http://www.mcgillairflow.com/textDocs/techTools/converted/thermalData1.php</a><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'>This calculator is really meant for exterior applications as well as determining if condensation will occur (and you have to use their preset products for insulation thickness & k values), but it can be a quick reference for us looking to see what an avg heat loss might be in a duct system. (I’m sure there’s a reference to the ASHRAE handbooks, but I’m drawing a blank right now…)<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'>What I am unsure of in eQuest is how it uses Supply Duct UA and Duct Delta T. If heat is lost in the duct, is it gained in the ceiling space or plenum?? If that is the case, then the arguments below that the overall net effect is negligible is a good one. However, fan energy will increase since the delta T of the supply air to room air decreases.<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'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D'>Andy Phelps, PE, LEED AP | </span><span style='font-size:10.0pt;font-family:"Arial Black","sans-serif";color:#4F6228'>BARNES & DODGE, INC</span><b><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#4F6228'>.</span></b><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:#1F497D'> | <a href="mailto:aphelps@barnesanddodge.com">aphelps@barnesanddodge.com</a> | (o) 913-321-6444 | (c) 913-710-7915 | <o:p></o:p></span></p><p class=MsoNormal><b><i><span style='font-size:8.0pt;font-family:"Arial Narrow","sans-serif";color:gray'>The information contained in this electronic message is confidential and is or may be protected by trade secret protections, and/or other applicable protections from disclosure. If the reader of this message is not the intended recipient, you are hereby notified that any use, dissemination, distribution or reproduction of this communication is strictly prohibited. If you have received this communication in error, please immediately notify us by calling 913-321-6444, or by e-mail to <u><a href="mailto:front@barnesanddodge.com" title="mailto:front@barnesanddodge.com"><span style='color:gray'>front@barnesanddodge.com</span></a></u>, and immediately delete this e-mail message and any attachments thereto. Although this e-mail message and any attachments are believed to be free of any virus or other defect that might negatively affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by Barnes & Dodge, Inc. for any loss or damage arising in any way in the event that such a virus or defect exists. Thank you.</span></i></b><b><i><span style='font-size:8.0pt;font-family:"Arial Narrow","sans-serif";color:gray'><o:p></o:p></span></i></b></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'><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'><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"'> equest-users-bounces@lists.onebuilding.org [mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Paul Diglio<br><b>Sent:</b> Tuesday, March 29, 2011 7:32 PM<br><b>To:</b> Nick Caton; McArdle, Mike; xiaoyang shi; equest-users@lists.onebuilding.org<br><b>Subject:</b> Re: [Equest-users] question about inefficiency of duct<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt'>Nick:<br><br>For a supply duct passing through a plenum return ceiling during the cooling season, the temperature difference between the supply air and return air can be as much as 25 degrees.<br><br>During the heating season, this difference could be as much as 30 degrees during morning warm up.<br><br>Paul Diglio<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:10.0pt'><o:p> </o:p></span></p><div><div class=MsoNormal align=center style='text-align:center'><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><hr size=1 width="100%" align=center></span></div><p class=MsoNormal style='margin-bottom:12.0pt'><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"'> Nick Caton <ncaton@smithboucher.com><br><b>To:</b> Paul Diglio <paul.diglio@sbcglobal.net>; "McArdle, Mike" <Mike.McAardle@state.vt.us>; xiaoyang shi <xs2144@gmail.com>; equest-users@lists.onebuilding.org<br><b>Sent:</b> Tue, March 29, 2011 8:03:32 PM<br><b>Subject:</b> RE: [Equest-users] question about inefficiency of duct</span><o:p></o:p></p><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>I think Mike’s general point is fair and isn’t to be taken in absolutes. </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>When a ducted return air stream is passing through a conditioned space or plenums/chases in between other conditioned spaces, it’s probably a safe bet to claim any duct gains/losses are *negligible* (not nonexistent), particularly if said return ducts are insulated, due to the relatively small delta-T.</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>On the other hand, winter losses and summertime gains at extreme temperatures may be considerable if any ductwork is routed exterior to the building, even if insulated. </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Xiaoyang, if you wish to calculate it as a percentage at design conditions: ( U x A x deltaT )<sub>DUCT</sub> / (total building heating or cooling load) x 100</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>If you wanted to model such exterior duct heat losses/gains in eQuest… I haven’t considered that before – but depending on your system setup, it might be as simple as a small exterior wall surface with appropriate U-value and area equal to the duct surface area… in the event the solar loads incident on the duct might be significant, make a point to correctly locate the surface in 3D (over the roof, along a wall, etc.) to avoid any incorrect self-shading from other surfaces.</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>If anyone has delved into this and knows a better/simpler way please do share =).</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>~Nick</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'><img border=0 width=119 height=37 id="Picture_x0020_1" src="cid:image001.jpg@01CBEEAB.6E45FD50" alt="cid:489575314@22072009-0ABB"></span><o:p></o:p></p><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#2D4D5E'> </span></b><o:p></o:p></p><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#2D4D5E'>NICK CATON, E.I.T.</span></b><o:p></o:p></p><p class=MsoNormal><span style='font-size:7.5pt;font-family:"Arial","sans-serif";color:#CC9900'>PROJECT ENGINEER</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#2D4D5E'>Smith & Boucher Engineers</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#2D4D5E'>25501 west valley parkway</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#2D4D5E'>olathe ks 66061</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#2D4D5E'>direct 913 344.0036</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#2D4D5E'>fax 913 345.0617</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><a href="http://www.smithboucher.com">www.smithboucher.com</a></span><u><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:blue'> </span></u><o:p></o:p></p></div><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><div><div style='border:none;border-top:solid windowtext 1.0pt;padding:3.0pt 0in 0in 0in;border-color:-moz-use-text-color -moz-use-text-color'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> equest-users-bounces@lists.onebuilding.org [mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>Paul Diglio<br><b>Sent:</b> Tuesday, March 29, 2011 4:59 PM<br><b>To:</b> McArdle, Mike; xiaoyang shi; equest-users@lists.onebuilding.org<br><b>Subject:</b> Re: [Equest-users] question about inefficiency of duct</span><o:p></o:p></p></div></div><p class=MsoNormal> <o:p></o:p></p><div><div><p class=MsoNormal><span style='font-size:10.0pt'>Michael:<br><br>"if the air in duct is the same air as the air being supplied to the space, there is no net effect"? What do you mean by net effect?<br><br>The duct heat loss/gain depends on the difference of the temperature of the air in the duct and the temperature of the air surrounding the outside of the duct. It is highly unlikely that these temperature will be the same.<br><br>Paul Diglio</span><o:p></o:p></p></div><div><p class=MsoNormal><span style='font-size:10.0pt'> </span><o:p></o:p></p><div><div class=MsoNormal align=center style='text-align:center'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><hr size=1 width="100%" align=center></span></div><p class=MsoNormal style='margin-bottom:12.0pt'><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> "McArdle, Mike" <Mike.McAardle@state.vt.us><br><b>To:</b> xiaoyang shi <xs2144@gmail.com>; "equest-users@lists.onebuilding.org" <equest-users@lists.onebuilding.org><br><b>Sent:</b> Tue, March 29, 2011 5:39:40 PM<br><b>Subject:</b> Re: [Equest-users] question about inefficiency of duct</span><o:p></o:p></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Dear xiaoyang shi</span><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>It Depends on the temperature differentials between air in duct and space and insulation thickness </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>But more importantly , if the air in duct is the same air as the air being supplied to the space there is no net effect </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Thank you, Sincerely,</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Michael J. McArdle , P.E.</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Buildings Engineer II, Project Manager </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>State of Vermont, </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Buildings and General Services (BGS)</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>2 Governor Aiken Avenue</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Montpelier, Vt. 05633</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Office: 802-828-5650; cell: 802-272-4828</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Arial","sans-serif";color:#1F497D'> </span><o:p></o:p></p><div style='border:none;border-top:solid windowtext 1.0pt;padding:3.0pt 0in 0in 0in;border-color:-moz-use-text-color -moz-use-text-color'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> equest-users-bounces@lists.onebuilding.org [mailto:equest-users-bounces@lists.onebuilding.org] <b>On Behalf Of </b>xiaoyang shi<br><b>Sent:</b> Tuesday, March 29, 2011 5:37 PM<br><b>To:</b> equest-users@lists.onebuilding.org<br><b>Subject:</b> [Equest-users] question about inefficiency of duct</span><o:p></o:p></p></div><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>Hi folks,<br><br>In the winter time, some heat loss in HVAC is from duct.<br><br>What is the percentage of heat loss through the duct to the total building heat load, due to the inefficiencies of duct delivery system?<br><br>Thank you guys.<o:p></o:p></p></div></div></div></div></div></div></div></div></div></body></html>