Prior to your response, i got a little impatient and found some of your past articles in the archives after a lot of digging. <div><br></div><div>I found out that the EIR equation is actually a % of the EIR that needs to be taken into account. So the equation should output a value from 1 to 0 to multiply the design rated EIR by to get the usage at that part load. there was a method that i found that, when the manufacturer doesn't provide you with enough to populate all three of the custom curves, you can simply use the EIR f(PLR) curve, which i did and got the results i expected to see. </div>
<div><br></div><div>Thanks for your response, both past and present.</div><div><br></div><div>Rob<br><br><div class="gmail_quote">On Wed, Jul 20, 2011 at 1:06 PM, Nick Caton <span dir="ltr"><<a href="mailto:ncaton@smithboucher.com">ncaton@smithboucher.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="font-size:11.0pt;color:#1F497D">Hi Rob!<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Well to start, let’s not assume every chiller out there
MUST be more efficient than the default curve at every point. Better to
assume they can and should differ.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">With that disclaimer out of the way, you have noted your
coefficients generated for your custom PLR curve should produce a lower correction
factor at 25% (confirmed in the Var 9 column you attached). <u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">What I think you’re missing is that there is indeed more
than one correction factor being calculated every hour, and more than one curve
in play to produce those factors that you need to consider. The extra
column you chose to include in your spreadsheet hints at this (Var 10).<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">Recommended DOE2 reading that should fill in these specific gaps
for you: </span>Volume 2: Dictionary<span> > </span>HVAC Components<span> > </span>CHILLER<span> > </span>Chiller Energy Consumption<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">There much further discussion on this topic in the archives as
well, if you just can’t get enough ;).<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D">~Nick<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><img width="119" height="37" src="cid:image001.jpg@01CC46D4.1CF43800" alt="cid:489575314@22072009-0ABB"></span><b><span style="font-size:11.0pt;color:#2D4D5E"><u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;color:#2D4D5E"><u></u> <u></u></span></b></p>
<p class="MsoNormal"><b><span style="color:#2D4D5E">NICK CATON, P.E.</span></b><b><span style="color:#2D4D5E"><u></u><u></u></span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:#CC9900">SENIOR ENGINEER<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:#CC9900"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">Smith & Boucher Engineers</span><span style="font-size:7.5pt;color:#CC9900"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">25501 west valley parkway, suite 200<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">olathe, ks 66061<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">direct <a href="tel:913.344.0036" value="+19133440036" target="_blank">913.344.0036</a><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">fax <a href="tel:913.345.0617" value="+19133450617" target="_blank">913.345.0617</a><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><a href="http://www.smithboucher.com" title="blocked::www.smithboucher.com" target="_blank"><span style="font-size:10.0pt;color:blue">www.smithboucher.com</span></a></span><u><span style="font-size:10.0pt;color:blue"> </span></u><span style="font-size:11.0pt;color:#1F497D"><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><u></u> <u></u></span></p>
<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: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>Rob
Hudson<br>
<b>Sent:</b> Wednesday, July 20, 2011 6:23 AM<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] Chiller Curves<u></u><u></u></span></p>
</div><div><div></div><div class="h5">
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I have a new Chiller Curve question/situation. I have
created a custom chiller curve for the EIR = f(PLR) as a cubic function using
the following data inputs:<u></u><u></u></p>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">1 .3313<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">.75 .2437<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">.5 .2201<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">.25 .1928<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">From my understanding, the chiller curve seems correct.
However, when i create a hourly report summary for the Corrected Chiller
EIR and compare it to the default EIR equation for this entry, i get 0.034 for
the default and 0.072 for my curve at 25% ratio. Why is it that the
default is better than my curve? I have looked at the equation for the
default entry and got the following equations:<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">EIR = a + b x = c x^2<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">a = .04812248<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">b = .69573420<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">c = .23493889<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">at 25% this equation results in 0.2367, and my equation gets
0.1928<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">Is there any other calculations going on in the background
that is causing some problems? I have attached an excel snapshot of the
different EIR and the corrected EIR values for two different chillers in my
program. Neither is currently using the default EIR = f(PLR) curves, they
are using custom curves.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">Thanks in advance,<br clear="all">
<br>
-- <br>
Rob Hudson<u></u><u></u></p>
</div>
</div></div></div>
</div>
</blockquote></div><br><br clear="all"><br>-- <br>Rob Hudson<br>
</div>