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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Hi Steve,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I’ve used both “averaging” approaches and “per system” calculations with success for per-zone baseline system types. I would reason project size / sheer system quantities into my decision to go one way or the other. I think it’s key in any case to be consistent in your documentation/calculations. <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Note the GBCI LEED spreadsheet has support for (paraphrasing) “typical of ## systems” baked in. At some point, it would be silly from all fronts (review and documentation) to separately document tons of nearly identical units in separate columns. If the reviewer should wish to spot check a couple individual cases, you can always provide complete SIM reports for the systems. If going along the “averaged” route, I’d use some of that time saved to clearly show my work for coming up with averaged system inputs as supporting documentation (and reference that upload in the Section 1.4 workbook alongside your “typical” system so that’s clear, for context).<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I also don’t think there’s precedent for forcing any particular doe-2 system type – you should be free to choose any system that best approximates what’s required.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Regarding # of systems per apartment: Whatever you do… don’t let any of that “real world common design sense” muddy the waters for interpreting baseline appendix G requirements! <o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>In all seriousness though, if there exists an actual design for reference showing a given apartment is actually multiple systems/zones, the onus falls on the modeler to determine those separate systems/zones (& even apartments) may be reasonably blocked together for having similar system properties & load profiles. If you aren’t comfortable making such assertions (and dealing with the consequential extra legwork for determining/documenting things like “average system size” for efficiency calculations later), then you can always fall back to drawing up zoning to reflect as many systems/zones as will actually exist. I try to weigh such end-to-end considerations at the outset of model zone mapping, where applicable.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>~Nick<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:#3A7A46'>------------------------------------------------------------------------------------------------------------------------------<o:p></o:p></span></p><p class=MsoNormal><b><span style='font-family:"Arial","sans-serif";color:#3A7A46'>Nick Caton, P.E.</span></b><span style='color:#3A7A46'><o:p></o:p></span></p></div><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0 width=724 style='width:543.0pt;border-collapse:collapse'><tr><td width=230 valign=top style='width:172.3pt;padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'> Senior Energy Engineer</span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'> Energy and Sustainability Services</span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'> North America Operations</span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'> Schneider Electric</span><span style='color:#1F497D'><o:p></o:p></span></p></td><td width=291 valign=top style='width:218.3pt;padding:0in 0in 0in 0in'><p class=MsoNormal><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#57B069'>D </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>913.564.6361 </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#57B069'>M </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>785.410.3317 </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#57B069'>E </span><span style='color:#1F497D'><a href="mailto:nicholas.caton@schneider-electric.com"><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>nicholas.caton@schneider-electric.com</span></a></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#1F497D'><br></span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#57B069'>F </span><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>913.564.6380</span><span style='color:#1F497D'><o:p></o:p></span></p></td><td width=203 valign=top style='width:152.4pt;padding:0in 0in 0in 0in'><p class=MsoNormal align=right style='text-align:right'><span style='font-size:8.0pt;font-family:"Arial","sans-serif";color:#626469'>15200 Santa Fe Trail Drive<br>Suite 204<br>Lenexa, KS 66219<br>United States</span><span style='color:#1F497D'><o:p></o:p></span></p></td></tr><tr style='height:4.0pt'><td width=724 colspan=3 valign=top style='width:543.0pt;padding:0in 0in 0in 0in;height:4.0pt'><p class=MsoNormal style='mso-line-height-alt:4.0pt'><span style='color:#3A7A46'><img border=0 width=722 height=49 id="Picture_x0020_3" src="cid:image001.png@01D18C20.49941A60" alt="cid:image001.png@01D189AB.58634A10"><o:p></o:p></span></p></td></tr></table><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='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 [<a href="mailto:equest-users-bounces@lists.onebuilding.org">mailto:equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Steve Jacobs<br><b>Sent:</b> Thursday, March 31, 2016 12:07 PM<br><b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> [Equest-users] Baseline PTAC/PTHP calc<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m starting to realize that there is a fairly large range of approaches when calculating the PTAC EER value for a baseline model. A simplified approach I’ve always used is to get the baseline EER is to take the total cooling capacity of all the apartments, and then divided that by the total number of units. Then use this average value to calculate EER. I’ve used this approach on a lot of LEED projects and never had a problem. I’m curious if others are calculating in on a unit by unit basis. My approach does take into account that top floor and corner units will probably need bigger and less efficient units. But calculating it on a unit by unit basis could also become very tedious, where a small change in the baseline model could necessitate the re-calculation of every system’s EIR. Also, this all assumes one PTAC unit per apartment. But in a real world design you could easily have one in the living room and a different unit in the bedroom.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’m just curious what approach people use on this calculation.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Also, I’ve found the controls on the actual PTAC unit a little restrictive so I’ve been using PSZ to model the PTAC systems at times and changing the performance curves.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoListParagraph style='text-indent:-.25in'>-<span style='font-size:7.0pt;font-family:"Times New Roman","serif"'> </span>Steve<o:p></o:p></p></div></body></html>