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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">eQUEST’s defaults will be important here for pressure drop in the two systems, ability to modulate airflow or chilled water flow, ability to economize (although Google shows your company near the Gulf, so if this is a local auto dealer then maybe economizer won’t be important).</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">The use of the chiller system’s cooling efficiency and pump power will be important since these are known, and may vary from the wizard’s suggestion. You’ll also need to make sure the DX system efficiency and fan power is realistic.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">The part-load performance of the system could also be important if the hours for the shop and show room are different – this could be a case where two or more right-sized DX systems may be a better match than one chiller, depending on the magnitude for the loads and if the zones have wildly different hours of operation.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">My suggestion would be to set eQUEST aside for a half hour, and just run through a table for the fan power, pump power, and cooling efficiency for each of the two cases and see if the answer jumps out at you. If you get pointed strongly in one direction, then review the eQuest files more closely to be sure you are capturing all of the part-load effects.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Regarding your ASHRAE 90.1 baseline suggestions, that might be your best “baseline” and then compare the proposed CHW and an enhanced DX system against that, but shouldn’t be necessary other than as Nick suggests for a QA reference.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">David</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><u><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black"> </span></u><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"></span></p>
<p class="MsoNormal"><span style="font-size:8.0pt;font-family:"Calibri","sans-serif";color:black"> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">David S. Eldridge, Jr., P.E., LEED AP BD+C, BEMP, BEAP, HBDP</span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#244061">Grumman/Butkus Associates</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"></span></p>
<p class="MsoNormal"><u><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black"> </span></u><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:black"> </span><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"></span></p>
</div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";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;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a> [mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Matt Clough<br>
<b>Sent:</b> Tuesday, April 24, 2012 7:37 AM<br><b>To:</b> Nick Caton; <a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> Re: [Equest-users] EEM vs. new model</span></p>
</div></div><p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">I suppose I should have been more specific in my description:</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">By baseline I mean the proposed design. So the program outputs 2 sim files – the base(proposed, CHW) case and the iterated (DX) case</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">We want to use eQuest to validate the system choice on this particular project. This is work that was started before I joined, but I have been selected to try and use eQuest to compare the performance of a chilled water system and a DX system. I’m not the most experienced energy modeler, but it seems like a task that would be a good application for eQuest. </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"> </span></p><p class="MsoNormal" style="text-indent:.5in"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">My approach was to simulate the energy consumption of a building that is similar to the actual design in orientation, shape, and square footage. I initially built the model in the SD wizard, using most of the default values (building envelope, activity usage, etc.), autosize the equipment, and use the EEM to compare the two systems. The idea was that when the building construction and geometry are equal, we can look at the relative energy consumption of the two systems. This initial simulation reported that the DX system would be more efficient, which is not what I had expected based on the design that had been selected.</span></p>
<p class="MsoNormal" style="text-indent:.5in"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">So I figured that maybe my model was too generic, too simple. I created zones based on the plans, and made the geometry more representative of the actual building. These changes produced reports that suggest the chilled water system is more efficient than the DX. I realized that the EEM was incorrectly modeling the change – it was treating the chilled water system as having all 8 air handlers, but was modeling the DX system as one AHU. So I created a duplicate model that has a DX system (autosized and using equest defaults). </span></p>
<p class="MsoNormal" style="text-indent:.5in"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">The comparison of these two models suggests the DX system is slightly more efficient. Unfortunately, my lack of experience makes me doubt the validity of this comparison – especially considering that the engineers selected a chilled water system for this project. </span></p>
<p class="MsoNormal" style="text-indent:.5in"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"> </span></p><p class="MsoNormal" style="text-indent:.5in"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">So I suppose my questions are: Does my approach seem valid? Is this an appropriate use of the software?</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">After taking some time to write this note, and with a little rest, I wonder if comparing the proposed design to an ASHRAE 90.1 baseline would have been a better approach.</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Regards,</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">Matt Clough</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy"> </span></p>
<div><div class="MsoNormal" align="center" style="text-align:center"><hr size="2" width="100%" align="center"></div><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Nick Caton [mailto:<a href="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>] <br>
<b>Sent:</b> Monday, April 23, 2012 3:40 PM<br><b>To:</b> Matt Clough; <a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> RE: EEM vs. new model</span></p></div><p class="MsoNormal">
</p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">By context, I gather by ‘baseline’ you mean something other than your proposed design, such as an 90.1 Appendix G baseline or similar.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">If that’s the case, my general advice is that you should <u>much</u> more heavily weight the comparative results using your “actual/proposed” model. A baseline per above inherently diverges from the actual building materials, lighting power densities, solar load shading, and so forth. It’s not the same building.</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Best to choose systems that most efficiently handle your actual project. Don’t get too hung up what works best for an imaginary building ;).</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">~Nick</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><img width="119" height="37" id="Picture_x005f_x005f_x005f_x0020_1" src="cid:image001.jpg@01CD220C.5531EE60" alt="cid:489575314@22072009-0ABB"></span><b><span style="font-size:11.0pt;font-family:"Stylus BT","sans-serif";color:#2d4d5e"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Stylus BT","sans-serif";color:#2d4d5e"> </span></b></p><p class="MsoNormal"><b><span style="font-family:"Stylus BT","sans-serif";color:#2d4d5e">NICK CATON, P.E.</span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Calibri","sans-serif";color:#cc9900">SENIOR ENGINEER</span></p><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Calibri","sans-serif";color:#cc9900"> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2d4d5e">Smith & Boucher Engineers</span><span style="font-size:7.5pt;color:#cc9900"></span></p><p class="MsoNormal">
<span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2d4d5e">25501 west valley parkway, suite 200</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2d4d5e">olathe, ks 66061</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2d4d5e">direct 913.344.0036</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#2d4d5e">fax 913.345.0617</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><a href="www.smithboucher.com" title="blocked::www.smithboucher.com"><span style="font-size:10.0pt">www.smithboucher.com</span></a></span><u><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:blue"> </span></u><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"></span></p>
</div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";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;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a> [mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a>] <b>On Behalf Of </b>Matt Clough<br>
<b>Sent:</b> Monday, April 23, 2012 1:59 PM<br><b>To:</b> <a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br><b>Subject:</b> [Equest-users] EEM vs. new model</span></p></div></div>
<p class="MsoNormal"> </p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Salutations eQuesters,</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">I’m doing a simple comparison between a chilled water and DX system. It would seem that this is a great opportunity to use the EEM, and the simulation predicted that the CHW configuration would be more energy efficient than the DX system. To be conservative, I also made a copy of the baseline model and changed the system from chilled water to DX. Using this method, the simulation predicts that the DX system would be more efficient (although not by much). Which result is most accurate? The building is a car dealership with a large showroom and an air-conditioned parts storage area.</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">The geometry and building envelope are not exact, but I made this decision because we are doing this for comparison purposes, so the geometry and construction will be the same. </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">I have let eQuest autosize both systems.</span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Sincerely, </span></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Matt Clough</span></p>
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