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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">All,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">This is a great example in contrasting styles of applying Appendix G for energy rating and I’m torn between the two as my message indicated. Both provide reasonable
justification for their conclusions. Thanks Paul and Nathan. This is the kind of thing USGBC/GBCI should be addressing in the LEED Energy Modeling Guide and eventually ASHRAE. It’s also an example of why California is going to the CBECC-Com process for determining
compliance with energy models.<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"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black">Fred Porter, BEMP, LEED</span></b><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">©</span></b><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black">
AP<o:p></o:p></span></b></p>
<p class="MsoNormal" style="margin-bottom:2.0pt"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F">Senior Energy Analyst<o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#005DAA">Architectural Energy Corporation<o:p></o:p></span></b></p>
<p class="MsoNormal"><i><span style="font-size:9.0pt;font-family:"Calibri","sans-serif";color:#005DAA">A Member of NORESCO Energy and Sustainability Services<o:p></o:p></span></i></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F">2540 Frontier Ave, Suite 100, Boulder, CO 80301<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#7F7F7F">Phone 303.459.7425 |
<a href="mailto:fporter@archenergy.com">fporter@archenergy.com</a><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#807F83"><a href="http://www.archenergy.com">www.archenergy.com</a></span><span style="font-size:9.0pt;font-family:"Calibri","sans-serif";color:#807F83"><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>
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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""> Paul Riemer [mailto:Paul.Riemer@dunhameng.com]
<br>
<b>Sent:</b> Wednesday, February 26, 2014 12:04 PM<br>
<b>To:</b> 'Nathan Miller'; Porter, Fred AEC; bldg-sim@lists. onebuilding. org (bldg-sim@lists.onebuilding.org)<br>
<b>Subject:</b> [External] RE: ASHRAE App G VAV Fan Curve<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<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>
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<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>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><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"">
<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a> [<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">mailto:bldg-sim-bounces@lists.onebuilding.org</a>]
<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 (<a href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a>)<br>
<b>Subject:</b> Re: [Bldg-sim] ASHRAE App G VAV Fan Curve<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<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>
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<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>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><o:p> </o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b>From:</b>
<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">bldg-sim-bounces@lists.onebuilding.org</a> [<a href="mailto:bldg-sim-bounces@lists.onebuilding.org">mailto:bldg-sim-bounces@lists.onebuilding.org</a>]
<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 (<a href="mailto:bldg-sim@lists.onebuilding.org">bldg-sim@lists.onebuilding.org</a>)<br>
<b>Subject:</b> [Bldg-sim] ASHRAE App G VAV Fan Curve<o:p></o:p></p>
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<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>
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