<div dir="ltr">Jacob,<div><br></div><div>Happy to hear that other people are thinking the same. </div><div><br></div><div>I was into this subject on my own thoughts recently.</div><div><br></div><div>I would like to add in your list: Occupants' behavior actually which is not in the stage to be included into the prediction.</div><div>I would add commissioning as well along with controls simulation and controls operation.</div><div><br></div><div>Apologies because I haven't worked with LEED projects but I think the above applied in general to "the performance gap".</div><div><br></div><div>Really looking forward to hearing more about this subject as I am not that experienced engineer yet, but really interested in "the performance" side of buildings.</div><div><br></div><div>Best,</div><div>Maria-Lida Kounadi</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">2015-05-21 15:04 GMT+01:00 Jacob Dunn <span dir="ltr"><<a href="mailto:jdunn@eskewdumezripple.com" target="_blank">jdunn@eskewdumezripple.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal">Bldg-Sim Community – <u></u><u></u></p>
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<p class="MsoNormal">I’m trying to compile a list of why it might be inappropriate to compare Appendix G models to actual consumption data. This comes about because I recently got into a debate with one of my co-workers when looking at the infamous NBI chart/study
that shows little correlation to predicted and actual energy values of LEED buildings. I was trying to explain that the Appendix G model’s intent is NOT to be compared to actual consumption, as it is a modeling protocol aimed at creating consistent relative
comparisons for LEED points. <u></u><u></u></p>
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<p class="MsoNormal">Here are the reasons thus far that support this notion (that App G models shouldn’t be compared to actual data). Does anyone know of any resources out there that expand upon this? Or can you think other reasons?<u></u><u></u></p>
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</span></span><u></u>Appendix G does not take into account external shading, which can be critical in urban environments for accurate energy predictions<u></u><u></u></p>
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</span></span><u></u>Schedules are typically not created with the intent of being predictive. Overall building hours are adhered to, but detailed schedule creation is not usually in the scope of a LEED model (or is it, in your experience?). For instance,
typical plug load base values during unoccupied times are .3, this is a pretty big assumption.<u></u><u></u></p>
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</span></span><u></u>The App G model uses a TMY weather file, which can vary from the current weather year (I wonder on average by how much?)<u></u><u></u></p>
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</span></span><u></u>Infiltration values are assumed, unless blower door testing has been done (which is rare for commercial buildings).<u></u><u></u></p>
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</span></span><u></u>Thermostat values are modeled as consistent across the building, which is rarely the case in an actual operating building<u></u><u></u></p>
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<p class="MsoNormal">Any additional insight is much appreciated!<u></u><u></u></p>
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<p class="MsoNormal"><b><span style="font-size:8.0pt;font-family:"Arial",sans-serif;color:#7d7773;letter-spacing:.3pt">Jacob Dunn LEED AP BD+C</span></b><span style="font-size:8.0pt;font-family:"Arial",sans-serif;color:#7d7773;letter-spacing:.3pt"><br>
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