Bill summed it up really well, Katherine. Sometimes a client will think a calibrated model must match the real building by an unrealistically high number, like 1%. I really can't imagine an instance when that would be desirable. It certainly would be costly to achieve. <div>
<br></div><div>Usually the plan is to use the calibrated model as a tool to examine various energy saving measures/opportunities that the client may be interested in implementing. It is important to remember, in this case that you are looking at the usage between the calibrated model and the ECM model, so the 1% deviation is consistent in both and not a worry.</div>
<div><br></div><div>Carol<br><br><div class="gmail_quote">On Thu, Apr 28, 2011 at 12:03 PM, Bishop, Bill <span dir="ltr"><<a href="mailto:wbishop@pathfinder-ea.com">wbishop@pathfinder-ea.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div lang="EN-US" link="blue" vlink="purple"><div><p class="MsoNormal"><span style="color:#1F497D">Katherine,</span></p><p class="MsoNormal"><span style="color:#1F497D"> </span></p><p class="MsoNormal"><span style="color:#1F497D">The questions I would have for you (or your client) are:</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="color:#1F497D">Is this an existing building, or something in the design phase?</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="color:#1F497D">What is the model going to be used for?</span></p><p>
<span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="color:#1F497D">Is there something magical about the 1% number?</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="color:#1F497D">1% of what? Annual electrical consumption? Annual gas consumption? Both? Monthly electric/gas consumption? Monthly/annual electrical demand?</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="color:#1F497D">Why remove the plug loads? Even if everything else is modeled perfectly, plug loads are typically 10% or more of annual electrical consumption but can be all over the place.</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="color:#1F497D">“Easily adjusted” by whom? Does your client want you to hand them a model and let them make all subsequent adjustments?</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p><p class="MsoNormal"><span style="color:#1F497D">Even if you are an expert energy modeler, and there is monitored energy data available for the building down to the individual electrical panels or broken out by end use (lighting, plug loads, individual HVAC units etc.) you will be hard-pressed to get to within 1% on a month-by-month basis. Even 5% month-by-month is difficult. Sure, you can tweak to your heart’s content to get a model to match annual electric consumption within 1% based on prior year’s utility bills but to maintain a calibrated model to that tolerance after that would require a lot of work.</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p><p class="MsoNormal"><span style="color:#1F497D">I suggest searching the bldg-sim and equest-users archives for information about weather files.</span></p><p class="MsoNormal">
<span style="color:#1F497D"> </span></p><p class="MsoNormal"><span style="color:#1F497D">Oh, one more question – how much money does your client have?</span></p><p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">Regards,</span></p><p class="MsoNormal"><span style="color:#1F497D">Bill</span></p><p class="MsoNormal"><span style="color:#1F497D"> </span></p><div><p class="MsoNormal"><b><span style="font-size:10.0pt;color:black">William Bishop, PE, BEMP, LEED<sup>®</sup> AP </span></b><b><span style="font-size:10.0pt;color:#006600">|</span></b><b><span style="font-size:10.0pt;color:black"> </span></b><b><span style="font-size:10.0pt;color:black">Pathfinder Engineers & Architects LLP</span></b><b><span style="font-size:10.0pt;color:black"></span></b></p>
<p class="MsoNormal"><span style="font-size:9.0pt;color:black">Mechanical Engineer</span></p><p class="MsoNormal"><span style="font-size:5.0pt;color:black"> </span></p><p class="MsoNormal"><span style="margin-left:367px;margin-top:17px;width:60px;min-height:58px"><img width="60" height="58" src="?ui=2&ik=367e06555b&view=att&th=12f9d7f6d4ec6ef5&attid=0.0.1&disp=emb&zw" alt="Top 100 Rochester 2010"></span><span style="font-size:9.0pt;color:#1F497D">134 South Fitzhugh Street</span><span style="font-size:9.0pt;font-family:"Times New Roman","serif";color:#1F497D"> </span><span style="font-size:9.0pt;color:#1F497D">Rochester, NY 14608</span><span style="font-size:9.0pt;font-family:"Times New Roman","serif";color:#1F497D"><br>
</span><span style="font-size:9.0pt;color:#1F497D">T: <a href="tel:%28585%29%20325-6004" value="+15853256004" target="_blank">(585) 325-6004</a> </span><span style="font-size:9.0pt;color:black">Ext. 114</span><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D"> </span><span style="font-size:9.0pt;color:#1F497D">F: <a href="tel:%28585%29%20325-6005" value="+15853256005" target="_blank">(585) 325-6005</a></span><span style="font-size:9.0pt;color:black"></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;color:black"><a href="mailto:wbishop@pathfinder-ea.com" target="_blank">wbishop@pathfinder-ea.com</a> </span><span style="font-size:9.0pt;color:black"><a href="http://www.pathfinder-ea.com/" target="_blank">www.pathfinder-ea.com</a></span></p>
</div><p class="MsoNormal"><span style="font-size:18.0pt;font-family:Webdings;color:green">P</span><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:green"> </span><span style="font-size:7.5pt;font-family:"Times New Roman","serif";color:green">Sustainability – the forest AND the trees.</span><span style="font-size:18.0pt;font-family:Webdings;color:green"> P </span><span style="color:#1F497D"></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">From:</span></b><span style="font-size:10.0pt"> <a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a> [mailto:<a href="mailto:bldg-sim-bounces@lists.onebuilding.org" target="_blank">bldg-sim-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Katherine Louman-Gardiner<br>
<b>Sent:</b> Thursday, April 28, 2011 1:49 PM<br><b>To:</b> <a href="mailto:bldg-sim@lists.onebuilding.org" target="_blank">bldg-sim@lists.onebuilding.org</a><br><b>Subject:</b> [Bldg-sim] eQuest - Model verification</span></p>
</div></div><div><div></div><div class="h5"><p class="MsoNormal"> </p><p class="MsoNormal"><span lang="EN-CA">Hi All,</span></p><p class="MsoNormal"><span lang="EN-CA">Our client would like us to produce an eQuest model that</span></p>
<p><span lang="EN-CA"><span>a)<span style="font:7.0pt "Times New Roman""> </span></span></span><span lang="EN-CA">Can be easily adjusted to include current and recently recorded weather data</span></p><p><span lang="EN-CA"><span>b)<span style="font:7.0pt "Times New Roman""> </span></span></span><span lang="EN-CA">Can be easily adjusted to reflect space occupancies and lighting loads</span></p>
<p><span lang="EN-CA"><span>c)<span style="font:7.0pt "Times New Roman""> </span></span></span><span lang="EN-CA">Will reflect the actual building energy usage to within 1%</span></p><p class="MsoNormal"><span lang="EN-CA">Do any of you have experience trying to validate models like this? </span></p>
<p class="MsoNormal"><span lang="EN-CA">My concern is that models are approximations, and will not account for small changes in occupancy, outdoor weather, etc. </span></p><p class="MsoNormal"><span lang="EN-CA">I guess my questions are these:</span></p>
<p><span lang="EN-CA"><span>1)<span style="font:7.0pt "Times New Roman""> </span></span></span><span lang="EN-CA">Even if I manage to put in daily occupant and fan schedules based on actual use, will the model be accurate enough to take me within 1%?</span></p>
<p><span lang="EN-CA"><span>2)<span style="font:7.0pt "Times New Roman""> </span></span></span><span lang="EN-CA">We have been asked to remove plug loads (both for consumption purposes and cooling loads). Will this be too big of an assumption to get any accuracy out of the model in the future?</span></p>
<p><span lang="EN-CA"><span>3)<span style="font:7.0pt "Times New Roman""> </span></span></span><span lang="EN-CA">How do I modify the weather input file?</span></p><p><span lang="EN-CA"><span>4)<span style="font:7.0pt "Times New Roman""> </span></span></span><span lang="EN-CA">Are there any other ideas I’m missing that will help us validate a model as an absolute measure of actual building energy consumption?</span></p>
<p class="MsoNormal"><span lang="EN-CA">Thank you for your help,<br>Katherine</span></p><p class="MsoNormal"><span lang="EN-CA"> </span></p><p class="MsoNormal"><span lang="EN-CA">Katherine Louman-Gardiner, EIT</span></p>
<p class="MsoNormal"><span lang="EN-CA">Mechanical Engineer</span></p><p class="MsoNormal"><span lang="EN-CA"> </span></p></div></div></div></div><br>_______________________________________________<br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Carol Gardner PE<br>
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