<div dir="ltr">Dominique,<div><br></div><div>Short answer: You're getting negative/zero savings because you haven't defined any loop losses or a UA for the HW loop.</div><div><br></div><div>According to your inp file, you have a normal natural gas boiler. Non-condensing boilers operate more efficiently with reduced HW supply temperature only due to reduced jacket and piping losses. The stoichiometry of the process isn't changed when you change the supply temperature, but the savings of a HW reset are because cooler water looses less heat to the environment. This is very different than the savings associated with a CHW reset and a chiller in which the operating efficiency of the chiller is improved. Defining the losses (either by dT or UA) is a tricky business though in my opinion. For an existing building, you must account for all losses through the system as geometries change and environmental conditions change, and it would be easy to miss the mark. For a new building, the losses should be minimal with a good installation, so the savings with a HW reset should be minimal. The danger for any case is that you can make the savings be whatever you want depending on what value you give the loop UA.</div>
<div><br></div><div>Note that reducing your HW supply temperature will also decrease the capacity of your HHW coils which will cause an increase in either pump or fan energy, which is probably the source of your negative savings. This is a real concern in practice, and the HW supply temperature should really be optimized globally to minimize all system energy usage. Lower HW supply temperature is not always the less energy intensive option.</div>
<div><br></div><div>Boiler lockout is another issue (mentioned in your earlier email). Right now, I don't see it defined in your inp file. To model this, you want to give some availability schedule to the HHW loop either based on time of the year or outside drybulb. This will show savings in eQuest, possibly at the cost of unmet space conditions.</div>
<div><br></div><div>Aaron<br clear="all"><div><br></div>-- <br>Sent from my DynaTAC 8000x
<div><br></div><div><span style="font-family:arial,sans-serif;font-size:13px">---------- Forwarded message ----------</span><br style="font-family:arial,sans-serif;font-size:13px"><span style="font-family:arial,sans-serif;font-size:13px">From: "Dominique Michaud" <<a href="mailto:dominique@scengineers.net">dominique@scengineers.net</a>></span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">To: <<a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a>></span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">Cc: </span><br style="font-family:arial,sans-serif;font-size:13px"><span style="font-family:arial,sans-serif;font-size:13px">Date: Tue, 17 Sep 2013 09:51:22 -0700</span><br style="font-family:arial,sans-serif;font-size:13px">
<span style="font-family:arial,sans-serif;font-size:13px">Subject: Re: [Equest-users] HHW reset controls in eQuest</span><br style="font-family:arial,sans-serif;font-size:13px"><div lang="EN-US" link="blue" vlink="purple" style="font-family:arial,sans-serif;font-size:13px">
<p class=""><span style="color:rgb(31,73,125)">Fellow eQuest modelers,<u></u><u></u></span></p><p class=""><span style="color:rgb(31,73,125)"><u></u> <u></u></span></p><p class=""><span style="color:rgb(31,73,125)">I’m reposting my last query (see below) with an example of one of the eQuest models that I have been having trouble with. Again, I’m having trouble modeling some very simple (IMO) heating hot water/boiler energy efficiency measures. I’m just not seeing the amount of savings I’m expecting. I’m even seeing negative savings for some measures (this is especially frustrating).<u></u><u></u></span></p>
<p class=""><span style="color:rgb(31,73,125)"><u></u> <u></u></span></p><p class=""><span style="color:rgb(31,73,125)">My offer of a beer to anyone who helps me solve my problem still stands, though I’ll have to restrict my offer to US/Canada destinations. Did I mention I’m in <a href="http://travel.nytimes.com/2012/05/27/travel/san-diegos-thriving-craft-beer-scene.html?pagewanted=all&_r=0" target="_blank">San Diego</a>?<u></u><u></u></span></p>
<p class=""><span style="color:rgb(31,73,125)"><u></u> <u></u></span></p><p class=""><span style="color:rgb(31,73,125)">Thanks in advance for your help.<u></u><u></u></span></p><p class=""><span style="color:rgb(31,73,125)"><u></u> <u></u></span></p>
<p class="" style="text-align:justify"><b><span style="color:rgb(13,13,13)">Dominique Michaud </span></b><span style="color:rgb(13,13,13)">|</span><span style="color:rgb(0,0,110)"> </span>Project Engineer<b><span style="color:rgb(0,0,110)"><u></u><u></u></span></b></p>
<p class="" style="text-align:justify"><a href="http://www.scengineers.net/" target="_blank"><b><span style="color:rgb(0,0,110);text-decoration:none">SC Engineers, Inc.</span></b></a><b><span style="color:rgb(0,0,110)"><u></u><u></u></span></b></p>
<p class="" style="text-align:justify"><a href="http://maps.google.com/maps?hl=en&cp=40&gs_id=2&xhr=t&q=17075+Via+Del+Campo,+San+Diego,+CA+92127&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=583&wrapid=tljp132371020953200&um=1&ie=UTF-8&hq=&hnear=0x80dbf72707811bcf:0xafda74b7e473e651,17075+Via+Del+C" target="_blank"><span style="color:rgb(13,13,13);text-decoration:none">17075 Via Del Campo, San Diego, CA 92127</span></a><span style="color:rgb(13,13,13)"><u></u><u></u></span></p>
<p class="" style="text-align:justify"><span style="color:rgb(13,13,13)">P: <a href="tel:858.946.0333" value="+18589460333" target="_blank">858.946.0333</a> | C: <a href="tel:858.436.4213" value="+18584364213" target="_blank">858.436.4213</a> |F: <a href="tel:858.946.0334" value="+18589460334" target="_blank">858.946.0334</a><u></u><u></u></span></p>
<p class="" style="text-align:justify"><a href="mailto:dominique@scengineers.net" target="_blank"><span style="color:windowtext;text-decoration:none">dominique@scengineers.net</span></a><span style="color:rgb(13,13,13)"> | </span><a href="http://www.scengineers.net/" target="_blank"><span style="color:rgb(13,13,13);text-decoration:none">www.scengineers.net</span></a><u></u><u></u></p>
<p class=""><u></u> <u></u></p><p class=""><span style="color:rgb(31,73,125)"><u></u> <u></u></span></p><p class=""><span style="color:rgb(31,73,125)"><u></u> <u></u></span></p><div><div style="border-style:solid none none;border-top-color:rgb(181,196,223);border-top-width:1pt;padding:3pt 0in 0in">
<p class=""><b><span style="font-size:10pt;font-family:Tahoma,sans-serif">From:</span></b><span style="font-size:10pt;font-family:Tahoma,sans-serif"> Dominique Michaud [mailto:<a href="mailto:dominique@scengineers.net" target="_blank">dominique@scengineers.net</a>] <br>
<b>Sent:</b> Friday, September 13, 2013 5:35 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> HHW reset controls in eQuest<u></u><u></u></span></p>
</div></div><p class=""><u></u> <u></u></p><p class="">Fellow eQuest modelers,<u></u><u></u></p><p class=""><u></u> <u></u></p><p class="">I am experiencing a great deal of grief trying to model HHW/boiler energy efficiency measures using eQuest. I am trying to model HHW temperature resets based on outside air temperature and boiler lockout strategies.<u></u><u></u></p>
<p class=""><u></u> <u></u></p><p class="">Under the DD Wizard, “Hot Water System Control and Schedule > Setpoint is:” drop-down list I’ve selected “OA Reset” and allowed the resulting hi/low temperature values to default, namely HW Max Temp: 180.0F and HW Min Temp: 140.0F (see attached screenshot).<u></u><u></u></p>
<p class=""><u></u> <u></u></p><p class="">Digging into the BDL, I noticed this issue:<u></u><u></u></p><p class=""><u></u> <u></u></p><p class=""><span style="font-family:'Courier New'"> *5356 * "B5HW Lp Heat Reset Sch-D" = DAY-SCHEDULE-PD<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'"> *5357 * TYPE = RESET-TEMP<u></u><u></u></span></p><p class=""><span style="font-family:'Courier New'"> *5358 * SUPPLY-LO = 140<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'">-CAUTION-------------------------- === -------------------------------------------------------<u></u><u></u></span></p><p class=""><span style="font-family:'Courier New'">-CAUTION--- VALUE GREATER THAN MAXIMUM OF 0.1200E+03<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'"> *5359 * SUPPLY-HI = 180<u></u><u></u></span></p><p class=""><span style="font-family:'Courier New'">-CAUTION-------------------------- === -------------------------------------------------------<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'">-CAUTION--- VALUE GREATER THAN MAXIMUM OF 0.1200E+03<u></u><u></u></span></p><p class=""><span style="font-family:'Courier New'"> *5360 * OUTSIDE-LO = 30<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'"> *5361 * OUTSIDE-HI = 65<u></u><u></u></span></p><p class=""><span style="font-family:'Courier New'"> *5362 * ..<u></u><u></u></span></p>
<p class=""><u></u> <u></u></p><p class="">However, it looks as though the values are accepted for the reset schedule:<u></u><u></u></p><p class=""><u></u> <u></u></p><p class=""><span style="font-family:'Courier New'">-NOTE- - - DATA FOR B5HW Lp Heat Reset Sch-D<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'">-INPUT - - - - - - - - - - - - - - - - - - - - - - - - TYPE = RESET-TEMP<u></u><u></u></span></p><p class=""><span style="font-family:'Courier New'">-INPUT - - OUTSIDE-HI = 65.0000 F<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'">-INPUT - - OUTSIDE-LO = 30.0000 F<u></u><u></u></span></p><p class=""><span style="font-family:'Courier New'">-INPUT - - SUPPLY-HI = 180.0000 F<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'">-INPUT - - SUPPLY-LO = 140.0000 F<u></u><u></u></span></p><p class=""><span style="font-family:'Courier New'">-DEFAULT - - - - - - - - - - - - - - - - - - - - - - - DAY-HOURS = 1.0000<u></u><u></u></span></p>
<p class=""><span style="font-family:'Courier New'">-DEFAULT - DAY-HOURS = 24.0000<u></u><u></u></span></p><p class=""><u></u> <u></u></p><p class="">
<u></u> <u></u></p><p class="">When I run the model I end up negative natural gas savings (i.e. more gas usage than in my baseline case). No matter what dials I try to turn with this EE measure, I consistently end up with negative savings. Even more frustrating, when I try to run a OA temperature lockout for the boiler, I get even more energy use than my baseline model!<u></u><u></u></p>
<p class=""><u></u> <u></u></p><p class="">Can anyone provide me with some guidance on what I need to do to get my model to run these EEMs correctly? Help put me on the path to solving these problems and I will buy you a beer…<u></u><u></u></p>
<p class=""><u></u> <u></u></p><p class="">(Note: I am using eQuest 3.64 Build 7130 – the latest release)<u></u><u></u></p><p class=""><u></u> <u></u></p><p class="">Thank you for any assistance you can provide.<u></u><u></u></p>
<p class=""><u></u> <u></u></p><p class="">Yours,<u></u><u></u></p><p class=""><u></u> <u></u></p><p class="" style="text-align:justify"><b><span style="color:rgb(13,13,13)">Dominique Michaud </span></b><span style="color:rgb(13,13,13)">|</span><span style="color:rgb(0,0,110)"> </span>Project Engineer<b><span style="color:rgb(0,0,110)"><u></u><u></u></span></b></p>
<p class="" style="text-align:justify"><a href="http://www.scengineers.net/" target="_blank"><b><span style="color:rgb(0,0,110);text-decoration:none">SC Engineers, Inc.</span></b></a><b><span style="color:rgb(0,0,110)"><u></u><u></u></span></b></p>
<p class="" style="text-align:justify"><a href="http://maps.google.com/maps?hl=en&cp=40&gs_id=2&xhr=t&q=17075+Via+Del+Campo,+San+Diego,+CA+92127&gs_upl=&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1280&bih=583&wrapid=tljp132371020953200&um=1&ie=UTF-8&hq=&hnear=0x80dbf72707811bcf:0xafda74b7e473e651,17075+Via+Del+C" target="_blank"><span style="color:rgb(13,13,13);text-decoration:none">17075 Via Del Campo, San Diego, CA 92127</span></a><span style="color:rgb(13,13,13)"><u></u><u></u></span></p>
<p class="" style="text-align:justify"><span style="color:rgb(13,13,13)">P: <a href="tel:858.946.0333" value="+18589460333" target="_blank">858.946.0333</a> | C: <a href="tel:858.436.4213" value="+18584364213" target="_blank">858.436.4213</a> |F: <a href="tel:858.946.0334" value="+18589460334" target="_blank">858.946.0334</a><u></u><u></u></span></p>
<p class="" style="text-align:justify"><a href="mailto:dominique@scengineers.net" target="_blank"><span style="color:windowtext;text-decoration:none">dominique@scengineers.net</span></a><span style="color:rgb(13,13,13)"> | </span><a href="http://www.scengineers.net/" target="_blank"><span style="color:rgb(13,13,13);text-decoration:none">www.scengineers.net</span></a></p>
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