<div>Thank you Nick for your insights.</div>
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<div>Please anyone feel free to add comments, further questions regarding this subject!<br><br></div>
<div class="gmail_quote">---------- Forwarded message ----------<br>From: <b class="gmail_sendername">Nick Caton</b> <span dir="ltr"><<a href="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>></span><br>
Date: 2013/7/18<br>Subject: RE: [Equest-users] Overload problems.. again.<br>To: DongEun Kim <<a href="mailto:equested@gmail.com">equested@gmail.com</a>><br><br><br>
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<p><u></u><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><span>1.<span style="FONT:7pt 'Times New Roman'"> </span></span></span><u></u><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">Every model is a different circumstance, but I can share that I have not had problems with auto-sized chillers/boilers in relation to their capacity and what’s required of the secondary loop. As explained, more often than not it’s totally fine for the non-coincident secondary loop sums to total higher than the primary capacity sums. If you’ve bumped up capacities as you’ve described and still observe 200+ unmet hours, it’s pretty clear the source of the remaining unmet hours is elsewhere in your model. <u></u><u></u></span></p>
<p><u></u><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><span>2.<span style="FONT:7pt 'Times New Roman'"> </span></span></span><u></u><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">While I think it’s possible to do what you’re proposing and stay in the spirit of 90.1’s requirements, if at all possible I would avoid it as it’s a stretch to interpret things that way. Proposed should represent actual equipment capacities and baseline capacities should autosize (with oversizing factors as prescribed). <u></u><u></u></span></p>
<p><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">All told, I suspect you need to take a step back from these (probably erroneous) loop warnings: If you have to inflate <u>proposed</u> equipment capacities beyond their designed values to deal with unmet hours exceeding 90.1’s thresholds, that’s a sign something else is wrong in one or both models with respect to envelope, internals, or equipment sizing. If it were me, I would probably next review the model’s loads & scheduling against those of the designer sizing the equipment for any large discrepancies. <u></u><u></u></span></p>
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<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">~Nick<u></u><u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><img alt="cid:489575314@22072009-0ABB" src="cid:image001.jpg@01CE82CC.A2AB7D10" width="119" height="37"></span><b><span style="FONT-FAMILY:'Stylus BT','sans-serif';COLOR:#2d4d5e;FONT-SIZE:11pt"><u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span style="FONT-FAMILY:'Stylus BT','sans-serif';COLOR:#2d4d5e;FONT-SIZE:11pt"><u></u> <u></u></span></b></p>
<p class="MsoNormal"><b><span style="FONT-FAMILY:'Stylus BT','sans-serif';COLOR:#2d4d5e">NICK CATON, P.E.<u></u><u></u></span></b></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#cc9900;FONT-SIZE:7.5pt">SENIOR ENGINEER<u></u><u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#cc9900;FONT-SIZE:7.5pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">Smith & Boucher Engineers</span><span style="COLOR:#cc9900;FONT-SIZE:7.5pt"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">25501 west valley parkway, suite 200<u></u><u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">olathe, ks 66061<u></u><u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">direct 913.344.0036<u></u><u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">fax 913.345.0617<u></u><u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><a title="blocked::www.smithboucher.com" href="http://www.smithboucher.com/" target="_blank"><span style="FONT-SIZE:10pt">www.smithboucher.com</span></a></span><u><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:blue;FONT-SIZE:10pt"> </span></u><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><u></u> <u></u></span></p></div>
<p class="MsoNormal"><b><span style="FONT-FAMILY:'Tahoma','sans-serif';FONT-SIZE:10pt">From:</span></b><span style="FONT-FAMILY:'Tahoma','sans-serif';FONT-SIZE:10pt"> DongEun Kim [mailto:<a href="mailto:equested@gmail.com" target="_blank">equested@gmail.com</a>] <br>
<b>Sent:</b> Tuesday, July 16, 2013 10:51 PM<br><b>To:</b> Nick Caton<br><b>Subject:</b> Re: [Equest-users] Overload problems.. again.<u></u><u></u></span></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Dear Nick and Rosie,<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">Your comments have helped me tremendously. Thank you!<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">I guess the key problem was that I trusted the program's autosizing ability too much.<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">I mean, even though I let both the air-side and water-side system to be autosized, I manually put capacities matching the loop peak load, and <u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">the PS-D overloads were all gone. And, the energy increase was trivial.<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">(I had my air-side systems to have sizing option of "Coincident", so the secondary peak demand exceeding the primary capacity may not<u></u><u></u></p></div>
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<p class="MsoNormal">have been an issue. And, my report showed unmet hours to be less than 200 hrs, so insufficient cooling/heating level may have been in an allowable range.)<u></u><u></u></p></div></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">But, I can't help feeling disappointed about unstable autosizing capability of eQuest. I mean, why the peak load in the PS-D doesn't match the peak load in PS-V when being autosized?<u></u><u></u></p>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">I have two more questions..<u></u><u></u></p></div>
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<p class="MsoNormal"><strong>1. should I still be so caught up with the overload problem even when the model has reasonable amount of unmet hours?</strong><u></u><u></u></p></div>
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<p style="MARGIN-BOTTOM:12pt" class="MsoNormal"><strong>2. Can I size the water-side plant for the Baseline(for the LEED project) with the same way (input the plant capacity to match the peak load in PS-D) I used for proposed? Or, Is there some sort of rule for the baseline model capacity to be left untouched?</strong><u></u><u></u></p>
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<p class="MsoNormal">2013/7/17 Nick Caton <<a href="mailto:ncaton@smithboucher.com" target="_blank">ncaton@smithboucher.com</a>><u></u><u></u></p>
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<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">All,</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">I’ve seen this topic come and go many times as well and have hesitated in the past to share my thoughts, but having spent enough time pondering this I figure I may as well share my opinions to further the discussion: </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">My understanding is that loop capacity warnings often fall in the category of attention messages that can easily be checked and dismissed as erroneous. </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">It’s my understanding one of two things is the usually case when you get one of these warnings: </span><u></u><u></u></p>
<p><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">1.</span><span style="COLOR:#1f497d;FONT-SIZE:7pt"> </span><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">Your primary hydronic heating/cooling equipment is actually of insufficient capacity to keep up with the highest demand incident on the loop, in which case you have a real problem that will likely manifest as significant block of unmet heating/cooling hours, assuming typical thermostat inputs. One way to check appropriate equipment sizing is to check the PEAK load for the loop/equipment of concern in the PS-C/PS-D reports against a tallied sum of the CAPACITY for all associated equipment, as reported in the PV-A report. Be mindful units are typically of different magnitude between these reports.</span><u></u><u></u></p>
<p><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">2.</span><span style="COLOR:#1f497d;FONT-SIZE:7pt"> </span><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">More commonly, the program has calculated a secondary capacity which exceeds the primary equipment capacities *in sum*. This secondary capacity is a “sum of maximum capacities” (i.e. the most each heating/cooling coil can do, as autosized/specified, in sum), and can easily be well in excess of the maximum hourly load incident on the primary equipment during the simulation. Another way to put it is there’s no “whole-building” diversity worked into the secondary capacity figure that shows up in the ATTN report. In such cases, the primary capacity as autosized/specified can in fact be just fine. </span><u></u><u></u></p>
<p style="MARGIN-LEFT:0.25in" class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">The designer sizing the primary equipment should be able to speak to what degree of diversity (if any) is intended for the whole building heating and cooling loads for determining equipment capacities. Different systems will have different ranges of “normal” for whole-building diversity, and it isn’t uncommon for hydronic cooling vs. heating systems to be designed with different capacity diversities for the same project.</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">I’d be interested to hear if others have a similar perspective or further insight as to when such cautions can be disregarded and when they’re cause for real concern.</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">Hope this helps you in the meantime Kim!</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt">~Nick</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><img border="0" alt="cid:489575314@22072009-0ABB" src="cid:image001.jpg@01CE82CC.A2AB7D10" width="119" height="37"></span><u></u><u></u></p>
<p class="MsoNormal"><b><span style="FONT-FAMILY:'Stylus BT','sans-serif';COLOR:#2d4d5e;FONT-SIZE:11pt"> </span></b><u></u><u></u></p>
<p class="MsoNormal"><b><span style="FONT-FAMILY:'Stylus BT','sans-serif';COLOR:#2d4d5e">NICK CATON, P.E.</span></b><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#cc9900;FONT-SIZE:7.5pt">SENIOR ENGINEER</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#cc9900;FONT-SIZE:7.5pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">Smith & Boucher Engineers</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">25501 west valley parkway, suite 200</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">olathe, ks 66061</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">direct 913.344.0036</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#2d4d5e;FONT-SIZE:10pt">fax 913.345.0617</span><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"><a title="blocked::www.smithboucher.com" href="http://www.smithboucher.com/" target="_blank"><span style="FONT-SIZE:10pt">www.smithboucher.com</span></a></span><u><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:blue;FONT-SIZE:10pt"> </span></u><u></u><u></u></p>
<p class="MsoNormal"><span style="FONT-FAMILY:'Calibri','sans-serif';COLOR:#1f497d;FONT-SIZE:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><b><span style="FONT-FAMILY:'Tahoma','sans-serif';FONT-SIZE:10pt">From:</span></b><span style="FONT-FAMILY:'Tahoma','sans-serif';FONT-SIZE:10pt"> <a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a> [mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>DongEun Kim<br>
<b>Sent:</b> Monday, July 15, 2013 7:22 PM<br><b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> [Equest-users] Overload problems.. again.</span><u></u><u></u></p>
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<p class="MsoNormal"> <u></u><u></u></p>
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<p class="MsoNormal">Hi All~<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">I've been posting about loop overload problem and still haven't got any responses.<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">In the archive, some equesters had cast questions regarding overload problems, but they don't seem to get answers either.<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">It it really that, no one knows how to fix it, or no one had experienced overload problems but us who question about it.<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">I just want to know why the over load is being shown in the loop report(PS-D),<u></u><u></u></p></div>
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<p class="MsoNormal">and any possible approach to fix the overload. <u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">Any advice or a mere comment will be a great help!<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">Thank you!<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div>
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<p class="MsoNormal">Kim<u></u><u></u></p></div>
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<p class="MsoNormal"> <u></u><u></u></p></div></div></div></div></div></div>
<p class="MsoNormal"><u></u> <u></u></p></div></div></div></div></div><br>