<div>Thanks Bill and Maria for your experience and advice. My terms of 'whacked' is not the same--here's my 'typical' scenario:</div>
<div> </div>
<div>Finished LEED equivalent model with 100% DD drawings;</div>
<div>Receive Value Engineering changes before I received the 100% CD drawings;</div>
<div>Low-and-behold the value engineering had changed the HVAC systems by approx 60% of what the original design was;</div>
<div>My proposed models are fine, BUT my 'new' baseline model (which is inline with the new proposed changes due to VE efforts) is now seeing underconditioned hours in the magnitude of 550 as opposed to 63 hours in my previous baseline model.....</div>
<div> </div>
<div>this is why it is whacked (by my own description): I had the baseline calibrated to an acceptable range, the VE changes really didn't make a big impact in the overall energy use (small impact), but for some reason I now have a new basline model where I am further behind the finish line than before these VE adjustments....I stared at this for 6 hours two nights ago with no progress or further insight what-so-ever. Ugh!</div>
<div> </div>
<div>I will try the suggestions by you and Maria and RB---thanks all for your tips. I hope I can get this fixed ASAP as I am working on multiple model projects that all need to be finished ASAP--as always. "Simulation Frustration" is the name of this game. ;)</div>
<div> </div>
<div>Cheers,</div>
<div>Pasha<br><br></div>
<div class="gmail_quote">On Fri, Sep 16, 2011 at 1:59 PM, Maria Karpman <span dir="ltr"><<a href="mailto:maria.karpman@karpmanconsulting.net">maria.karpman@karpmanconsulting.net</a>></span> wrote:<br>
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<p class="MsoNormal"><span style="COLOR: #1f497d; FONT-SIZE: 11pt">Pasha and Bill,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="COLOR: #1f497d; FONT-SIZE: 11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="COLOR: #1f497d; FONT-SIZE: 11pt">I also often use this keyword, but usually increase the fraction incrementally by 0.1 instead of just setting it to 1, to avoid out-of-control behavior described in DOE2 help. Here is the related quote: <u></u><u></u></span></p>
<p style="MARGIN-LEFT: 0.5in" class="MsoNormal">Some reverse-acting VAV systems may go out of control if the maximum heating airflow is not restricted . As the zone temperature drops, the box progressively opens to deliver more air. However, since the supply air is usually lower than the zone temperature, more coil energy is required to offset the non-useful reheat (difference between zone temperature and supply air temperature), potentially leaving less coil/boiler capacity available for useful heating. As a result, a terminal at full flow may deliver less useful heating than at lower flow, resulting in an out-of-control situation; the box may go to full flow even though a reduced flow would heat more effectively. The solution is to restrict the maximum flow during reheatng coil and/or boiler is not sized sufficiently large, <u></u><u></u></p>
<p class="MsoNormal"><span style="COLOR: #1f497d; FONT-SIZE: 11pt">I did see this scenario happen in some projects, when adjusting the value of the keyword up beyond certain point increased heating, cooling, and fan power, but did not help much with under-heating. <u></u><u></u></span></p>
<p class="MsoNormal"><span style="COLOR: #1f497d; FONT-SIZE: 11pt">Thanks,</span><u></u><u></u></p>
<p class="MsoNormal"><span style="COLOR: #1f497d; FONT-SIZE: 11pt">Maria <u></u><u></u></span></p>
<p class="MsoNormal"><span style="COLOR: #1f497d; FONT-SIZE: 11pt"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span style="FONT-SIZE: 10pt">From:</span></b><span style="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>Pasha Korber-Gonzalez
<div class="im"><br><b>Sent:</b> Friday, September 16, 2011 3:23 PM<br><b>To:</b> Bishop, Bill<br><b>Cc:</b> <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br></div>
<b>Subject:</b> Re: [Equest-users] Tip for unmet heating hours in VAV systems<u></u><u></u></span>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Thanks Bill--I think this will be helpful. I currently have a baseline model with whacked underheated hours and with upsizing ratios and autosized calcs nothing is changing for me. I will try this input adjustment and see if it works.<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">Thanks for sharing!<u></u><u></u></p></div>
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<p style="MARGIN-BOTTOM: 12pt" class="MsoNormal">Pasha<u></u><u></u></p></div>
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<p class="MsoNormal">On Fri, Sep 16, 2011 at 8:33 AM, Bishop, Bill <<a href="mailto:wbishop@pathfinder-ea.com" target="_blank">wbishop@pathfinder-ea.com</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal">Thought I’d share a tip for addressing unmet heating hours in VAV systems using eQUEST 3.64.<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">eQUEST 3.64 adds the HMAX-FLOW-RATIO keyword in System -> Fans -> Flow Parameters. The default value is the greater of the fan MIN-FLOW-RATIO and 0.5, but this value is determined by the program and you don’t see it when you look at the Flow Parameters tab. Entering a value of 1.0 corrected an unmet heating hours problem for me that appeared when I opened a model in 3.64 that I originally created in 3.63. This works for both VAVS and PVAVS system types.<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal">Regards,<u></u><u></u></p>
<p class="MsoNormal">Bill<u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p>
<p class="MsoNormal"><img border="0" alt="Senior Energy Engineer" src="cid:image001.jpg@01CC7486.7F10F840" width="486" height="116"><u></u><u></u></p>
<p class="MsoNormal"> <u></u><u></u></p></div></div>
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<p class="MsoNormal"><u></u> <u></u></p></div></div></div></div></blockquote></div><br>