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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'>Section 6.5.3.2.3 requires static pressure reset for VAV fan system with DDC of individual zones and I believe that requirement predates the fan curve in Appendix G. Given the prevalence of DDC zones, it seems disingenuous to claim savings for static pressure reset under Appendix G. Maybe there is room for claiming improved reset based on oversized ducts and boxes? It wouldn’t take much to run the different published VFD curves out there and use whichever one gives your project the most savings but that is clearly gaming the system. Since tools are not explicitly modeling the physics of static pressure reset, I suggest it should at least be isolated as an exceptional calculation for review.<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:9.0pt;font-family:"Verdana","sans-serif";color:#5F574F'>Paul Riemer, PE, LEED AP BD+C</span></b><span style='font-size:9.0pt;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:#C00000'>DUNHAM</span></b><span style='font-size:11.0pt;font-family:"Verdana","sans-serif";color:#C00000'><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>Nathan Miller<br><b>Sent:</b> Wednesday, February 26, 2014 12:42 PM<br><b>To:</b> Porter, Fred AEC; bldg-sim@lists. onebuilding. org (bldg-sim@lists.onebuilding.org)<br><b>Subject:</b> Re: [Bldg-sim] ASHRAE App G VAV Fan Curve<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'>I think it is pretty clear the way 90.1 App. G is written that you SHALL use that specific curve for the baseline VAV system fan power. Now it is a different discussion about whether that curve properly accounts for any ASHRAE required controls strategies, fan performance requirements, etc, but that doesn’t really matter, here is the curve to use. <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'>Proposed, as always, should accurately reflect how the system will operate. If you think a more advantageous fan curve is appropriate, such as to account for static pressure reset, go ahead and use it, just as you could create a custom curve for boiler or chiller part-load efficiencies. Don’t hide the fact, make it clear to the reviewer that you are using different curves, state the source for your proposed curve and see if they want to comment or challenge the results. <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'>For what it is worth (keeping in mind that past rulings do not set precedent), on multiple projects I have worked on I have used “static pressure reset” fan curves in the proposed, the mandatory baseline fan curve in the baseline, and it has never even been questioned by the reviewer. <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;mso-margin-bottom-alt:auto'><b>Nathan Miller - PE, LEED<sup>®</sup>AP BD+C, CEM<o:p></o:p></b></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><i>Mechanical Engineer/Senior Energy Analyst <o:p></o:p></i></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b>RUSHING</b> | <b>D</b> 206-788-4577 | <b>O</b> 206-285-7100<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><a href="http://www.rushingco.com/">www.rushingco.com</a><o:p></o:p></b></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>Porter, Fred AEC<br><b>Sent:</b> Wednesday, February 26, 2014 9:40 AM<br><b>To:</b> bldg-sim@lists. onebuilding. org (bldg-sim@lists.onebuilding.org)<br><b>Subject:</b> [Bldg-sim] ASHRAE App G VAV Fan Curve<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'>All,<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Does anyone know, particularly through having claims accepted by GBCI, whether the ASHRAE App G VAV fan curve is supposed to represent a fan system with or without static pressure reset. I always thought it was supposed to represent a system with sp reset, conforming to 6.5.3.2.3. However, most of the curve power values are even higher than curves representing VAV/VFD systems without sp reset. A confusing aspect is that compared to other VFD fan curves, the power values are high at high flows, but low at low flows, even going to zero at zero flow, though that is really meaningless.<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'>As an aside, the 2013 Title 24 ACM now defines fan curves for central VAV systems with and without sp reset, taken from Taylor’s VAV design guide. SP reset is the “baseline” or “standard.”A<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 for any experience or thoughts on 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'>Fred<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b>Fred Porter, BEMP, LEED© AP<o:p></o:p></b></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Senior Energy Analyst<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b>Architectural Energy Corporation<o:p></o:p></b></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><i>A Member of NORESCO Energy and Sustainability Services<o:p></o:p></i></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>2540 Frontier Ave, Suite 100, Boulder, CO 80301<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Phone 303.459.7425 | <a href="mailto:fporter@archenergy.com">fporter@archenergy.com</a><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><a href="http://www.archenergy.com">www.archenergy.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><p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p></div></body></html>