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</o:shapelayout></xml><![endif]--></head><body lang="EN-GB" link="#0563C1" vlink="#954F72" style="overflow-wrap: break-word; zoom: 0%;"><div dir="auto">Hello,<br><br></div>
<div dir="auto">This looks like a very interesting conversation. Unfortunately we once again get into a problem where not everyone is able to follow because the information is behind a paywall.<br></div>
<div dir="auto">It's not crystal clear to me what is "hardcore" about it. It is about using notmalized mean bias (NMBE) + CV(RMSE) instead of the more familiar Rsquared?<br></div>
<div dir="auto">If my limited memory serves, guideline 14 and the IPMVP protocol define, and explain, them properly.<br></div>
<div dir="auto">The first critical piece is to use actual weather data and not try to calibrate to a tmy3 file.<br></div>
<div dir="auto">I agree that daily (or hourly/subhourly) calibration is probably too optimistic, though again if memory serves the protocol has relaxed thresholds for that case.<br></div>
<div dir="auto">My two cents is that you should first Downsample the utility data to monthly, unless you have less than 12 months of data without any major changes (ECMs or unusual activities).<br></div>
<div dir="auto">If you have no period of 12 months without major external changes, massage the data. What's needed there depends on whether it's an ECM or unusual activity. If an ECM probably try to use 12 months before it If you can. If unusual, do a regression on the regular data, extrapolate the rest.<br></div>
<div dir="auto">As it's been said before, the key point is to document whatever assumptions you've taken clearly.<br><br></div>
<div dir="auto">Even when you have perfect data for 36 months of "regular operation" (whatever does that mean), and calibrate your model correctly, you'll still be off in the next 12 months if nothing happened.<br><br></div>
<div dir="auto">Never forget that you're dealing with 5000+ independent variables and trying to calibrate to 12month of one, or two, dependent variable(s) (utility data). It's a **grossly** overfit model. And that's why a careful audit is needed with existing buildings, so you can try to 1) get the history for the calibration period and 2) tune every variable you can so only the unknowns remain (typically nail the loads etc, leaving stuff that's not easily measured and very influential like infiltration when a blower door test is not practical)<br><br><br></div>
<div dir="auto">Disclaimer: writing on my phone so zero external resources available and probably a lot of typos.<br><br></div>
<div dir="auto">Best,<br></div>
<div dir="auto">Julien<br><br></div>
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<div class="gmail_quote" >On Mar 14, 2023, at 11:54, Chris Yates via Bldg-sim <<a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a>> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div class="WordSection1"><p class="MsoNormal">Hi All</p><p></p><p class="MsoNormal"></p><p> </p><p class="MsoNormal">I do find ASHRAE Guideline 14 a little too hardcore for my basic understanding of statistics. I can plug any of the equations into Excel, but I’ve realised my statistics understanding is very limited! (I’m outed!)</p><p></p><p class="MsoNormal"></p><p> </p><p class="MsoNormal">We don’t actually have to work to G14 in the UK (probably good because my copy is a bit old). I finally realised I didn’t know enough after I’d been (lazily) using R2 in Excel on some monthly data. I thought that R2 > 0.9 was generally ok… yeah, it wasn’t.</p><p></p><p class="MsoNormal"></p><p> </p><p class="MsoNormal">So, are there any easy to understand resources available?</p><p></p><p class="MsoNormal"></p><p> </p><p class="MsoNormal">I’ve been messing around with the IMT as well. It’s been fun going back to DOS <span style="font-family:"Segoe UI Emoji",sans-serif">😊</span>. This got me into daily methods, which leads to my next question. Is there any reason why there isn’t a daily calibration option specified in G14?</p><p></p><p class="MsoNormal"></p><p> </p><p class="MsoNormal">Many thanks!</p><p></p><p class="MsoNormal"></p><p> </p><p class="MsoNormal"><span style="mso-fareast-language:EN-GB">Chris Yates</span></p><p></p><p class="MsoNormal"></p><p> </p></div><pre class="blue"><hr><br>Bldg-sim mailing list<br><a href="http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org">http://lists.onebuilding.org/listinfo.cgi/bldg-sim-onebuilding.org</a><br>To unsubscribe from this mailing list send a blank message to BLDG-SIM-UNSUBSCRIBE@ONEBUILDING.ORG<br></pre></blockquote></div></body></html>