Hi Nick,<div><br></div><div>In my experience the EIRFLPR curve is not looking for a normalized efficiency. If you look at the default chiller curves you'll notice that the EIRFPLR correction factor actually decreases as you approach zero part-load. This would not make sense if it was an EIR correction factor, as the efficiency of the chiller actually increases as part-load decreases (at least with a variable speed chiller).</div>
<div><br></div><div>The chiller EIRFPLR curve is actually looking for a ratio of current kW power draw divided by kW power draw at full-load.</div><div><br></div><div>The thread from when I was struggling through this for the first time myself is located here: <a href="http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/2008-February/006827.html">http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/2008-February/006827.html</a></div>
<div><br></div><div><a href="http://lists.onebuilding.org/pipermail/bldg-sim-onebuilding.org/2008-February/006827.html"></a>Not all that useful as I believe someone assisted me through the process off-list, but the conclusion remains the same.</div>
<div><br></div><div>-Robby<br><br><div class="gmail_quote">On Wed, Jun 15, 2011 at 1:55 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="color:#1F497D">Hi
Lyle,</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">I
think you need to review a little further before proceeding. Read through the
attached discussion from the bottom up. This discussion diverges a bit (as
performance curve topics usually do) but I think you’re a bit ahead of the
curve so to speak (har har!) in recognizing what the IPLV numbers really mean.
Plugging in your IPLV values as coefficients for a cubic equation (where f(x) =
Ax^3+Bx^2+Cx+D) is pretty much wildly different from the correct course of
action, but you’re definitely in the ballpark’s parking lot ;).</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">Ultimately,
you (and others – listen up!) will probably have the best shot of getting it
right on the first go if you visualize what you’re doing in excel. That’s what
worked for me when I was climbing this mountain:</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><span style="color:#1F497D">Assemble your part
load percentages and corresponding EER’s in excel</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><span style="color:#1F497D">Stop and review what
the curve in eQuest is looking up, and from what variable(s). You can glean
this from the title of the default curve used… In this case, you want eQuest
to determine EIR each hour as a function of Part load (EIRfPLR). </span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><span style="color:#1F497D">Knowing that,
convert convert your EER values to to EIR</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><span style="color:#1F497D">Now, normalize each
EIR value to the ARI value*. If the EER at ARI is 9, and your 50% part load
EER is 6, then the normalized vaule is 6/9 = 0.67. This normalized number is
actually a multiplier of sorts that eQuest will apply against your specified ARI
efficiency in the chiller input window. If none of this is making sense, go
back further and review my “recommended reading” list in a thread called “Chiller
curves, oh boy!” from sometime last year in the archives.</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><span style="color:#1F497D">Using excel, plot
these normalized efficiencies (y-axis) against the part load ratios (x-axis)
with a scatter chart.</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><span style="color:#1F497D">Right click and add
a curve-fit to the series. In the dialog, try making it third order (quadratic)
and see if you get a good fit. Check the option to display the curve equation.</span></p>
<p><span style="font-family:Symbol;color:#1F497D"><span>·<span style="font:7.0pt "Times New Roman"">
</span></span></span><span style="color:#1F497D">Voila, there are
your four coefficients (A,B,C,D – see eQuest’s curve inputs to be sure you know
which is which in the quadratic format) for eQuest! You’ve also developed a
visual check to ensure the numbers make sense.</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">*Important:
You MUST work from ARI-condition data points, and normalize to the ARI condition,
and specify your chiller’s capacity/efficiency at ARI conditions, if you are
trying to only make PLR curves without doing a full set of custom curves. The
reasons why are complex, and I’ve already nearly written a book on the matter
in the archives if you’re itching to know why ^_^. If you want to specify your
chiller around design conditions, then it’s all or nothing (library curves)
with regard to custom curve creation!</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">A
general statement/consolation to everyone: We all have to crawl before we can
run! Make no mistake, coming to a true fundamental understanding of custom
curves in eQuest/DOE2, to the point you can manipulate and even create them on
your own, is no small feat. They should give out medals! The best way to
develop this skill set is to accept you will probably screw it up a few times
to start, look hard at your results, and read up on the literature/advice that’s
out there in order to learn what it is that you personally don’t know. Once
you come around to understanding what you do know, and more importantly what
you know that you don’t know… (<a href="http://en.wikiquote.org/wiki/Donald_Rumsfeld" target="_blank">Donald Rumsfeld would make
a good energy modeler, lol</a>), it’s all downhill from there, and you can begin
to ask the right questions of yourself and others to bridge your personal
gaps. Making mistakes is commendable, provided you resolve to learn from them!
</span></p>
<p class="MsoNormal"><span style="color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D">~Nick</span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="color:#1F497D"><img border="0" width="119" height="37" alt="cid:489575314@22072009-0ABB"></span><b><span style="color:#2D4D5E"></span></b></p>
<p class="MsoNormal"><b><span style="color:#2D4D5E"> </span></b></p>
<p class="MsoNormal"><b><span style="color:#2D4D5E">NICK CATON, P.E.</span></b><b><span style="color:#2D4D5E"></span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:#CC9900">SENIOR ENGINEER</span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:#CC9900"> </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"></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">25501 west valley parkway, suite 200</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">olathe, ks 66061</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></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></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><a href="http://www.smithboucher.com" title="blocked::www.smithboucher.com" target="_blank"><span style="font-size:10.0pt">www.smithboucher.com</span></a></span><u><span style="font-size:10.0pt;color:blue"> </span></u><span style="color:#1F497D"></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"><img border="0" width="119" height="37" alt="cid:489575314@22072009-0ABB"></span><b><span style="font-size:11.0pt;color:#2D4D5E"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;color:#2D4D5E"> </span></b></p>
<p class="MsoNormal"><b><span style="color:#2D4D5E">NICK CATON, P.E.</span></b><b><span style="color:#2D4D5E"></span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:#CC9900">SENIOR ENGINEER</span></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:#CC9900"> </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"></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">25501 west valley parkway, suite 200</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;color:#2D4D5E">olathe, ks 66061</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></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></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">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"></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;color:#1F497D"> </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>Robby
Oylear<br>
<b>Sent:</b> Wednesday, June 15, 2011 2:43 PM<br>
<b>To:</b> Lyle Keck<br>
<b>Cc:</b> <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Subject:</b> Re: [Equest-users] IPLV Curve Fit</span></p>
</div><div><div></div><div class="h5">
<p class="MsoNormal"> </p>
<p class="MsoNormal">Lyle,</p>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">The short answer is no. IPLV cannot be used to create
performance curves in eQUEST.</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Part-load curves are a strange animal in eQUEST. You'll need
cooperation from the chiller manufacturer to get the correct data. You
need to have enough data to describe the way energy varies as a function of
part-load, chilled water supply temp, and outside air temperature. Take a
look at the attached spreadsheet which can be used to create curves in eQUEST.
The data in yellow should be entered by the manufacturer or
manufacturer's rep. The data in red should be entered into eQUEST. </p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">If you look into the formulas, you'll note that EIR-FPLR is
actually not an EIR factor, it is based on the power draw of the equipment at
part-load compared to at full-load. This throws a lot of people off as it
is not described that way in the help documentation.</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">The interesting question that arises when working with custom
part-load curves is how accurate does the eQUEST default performance curve
model the required IPLV for the baseline per ASHRAE 90.1? In my
experience the default curve is approximately 10% worse than the IPLV
requirement.</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Hope this helps,</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Robby Oylear, LEED AP BD+C</p>
</div>
<div>
<p class="MsoNormal">Mechanical Project Engineer</p>
</div>
<div>
<p class="MsoNormal">Energy Analyst</p>
</div>
<div>
<p class="MsoNormal">Rushing</p>
</div>
<div>
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal">On Wed, Jun 15, 2011 at 10:59 AM, Lyle Keck <<a href="mailto:lkeck@aeieng.com" target="_blank">lkeck@aeieng.com</a>> wrote:</p>
<div>
<div>
<p class="MsoNormal">All,
<br>
<br>
I am trying to create a part load curve for an air-cooled screw chiller.
I have the EER & COP data for 100%, 75%, 50%, and 25% loading. </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I
have read through the various posts in the archives and I am still unsure if I
should input this data as ‘raw data’ or ‘coefficients’ </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">From
previous posts: </p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New""> </span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">IPLV (or NPLV) = 0.01A+0.42B+0.45C+0.12D</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">Where:</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">A = COP or EER @ 100% Load</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">B = COP or EER @ 75% Load</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">C = COP or EER @ 50% Load</span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">D = COP or EER @ 25% Load</span></p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">It
is my understanding that EIR-PLR curves give the EIR as a function of part load
ratio. </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">SO,
if I create a ‘cubic’ curve with input type ‘curve coefficients’, and input
a=(1/COP-100%), b=(1/COP-75%), c=(1/COP-50%), and d=(1/COP-25%) and specify
this curve as the EIR - f(part load ratio) curve, would that be accurate?
</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Additionally,
this chiller has a condenser water temp of 95 degF and design conditions that
differ from AHRI conditions (design EWT=58 degF and LWT=44 degF)</p>
<p class="MsoNormal">Do
these values have direct correlation to the curve creation ? Or can the
condenser and CHW temp simply be defined in the ‘basic specifications’ tab for
the chiller, and the EWT defined via the CHW loop deltaT?</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I
know this topic has been widely discussed, but I am still uneasy about the
actual inputs for the creation of the part load performance curve.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Any
input, or reference to a previous post would be appreciated.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Thanks
in advance,</p>
<p class="MsoNormal"> </p>
<table border="0" cellpadding="0" width="474" style="width:355.5pt">
<tbody><tr>
<td width="167" valign="top" style="width:125.25pt;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal"><b><span style="font-size:10.0pt;color:#660000;text-transform:uppercase">Lyle Keck</span></b><b><span style="font-size:9.0pt;color:#333333"> </span></b><span style="font-size:9.0pt;color:#333333"><br>
</span><span style="font-size:10.0pt;color:#333333;text-transform:uppercase">SustainablE
Systems Analyst</span></p>
</td>
<td width="10" valign="top" style="width:7.5pt;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal"><span style="font-size:9.0pt;color:#333333"> </span></p>
</td>
<td width="283" valign="top" style="width:212.25pt;padding:.75pt .75pt .75pt .75pt">
<p class="MsoNormal"><b><span style="font-size:9.0pt;color:#660000">AEI</span></b><span style="font-size:9.0pt;color:#333333"> | AFFILIATED ENGINEERS, INC. <br>
Westlake Center Office Tower, 1601 Fifth Avenue, Suite 1400 | Seattle, WA
98101<br>
<br>
</span><span style="font-size:9.0pt;color:#660000">P: <a href="tel:206.256.0800" target="_blank">206.256.0800</a> | F: <a href="tel:206.256.0423" target="_blank">206.256.0423</a></span><span style="font-size:9.0pt;color:#333333"> <br>
</span><span style="font-size:9.0pt;color:#660000"><a href="mailto:lkeck@aeieng.com" target="_blank"><span style="color:#660000;text-decoration:none">lkeck@aeieng.com</span></a> | <b><a href="http://www.aeieng.com/" target="_blank"><span style="color:#660000;text-decoration:none">www.aeieng.com</span></a></b></span><span style="font-size:9.0pt;color:#333333"> </span></p>
</td>
</tr>
</tbody></table>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
</div>
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><br>
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<p class="MsoNormal"> </p>
</div>
</div></div></div>
</div>
<br><br>---------- Forwarded message ----------<br>From: "Paul Diglio" <<a href="mailto:paul.diglio@sbcglobal.net">paul.diglio@sbcglobal.net</a>><br>To: "Nick Caton" <<a href="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>>, <<a href="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a>><br>
Date: Sat, 26 Feb 2011 07:15:46 -0500<br>Subject: Re: [Equest-users] using IPLV in eQuest<br>
<div><div style="font-family:times new roman,new york,times,serif;font-size:10pt">Nick:<br><br>I agree with your analysis. A curve built using different kW/Ton for the four different load ratios that are used in the IPLV calculation would be sufficient.<br>
<br>I would just be careful when creating a curve that uses different condenser water supply temperatures. It is more of a design issue. There has to be a reason why the condenser water temperature varies. It will effect the lift and kW/Ton. For example, current chillers will tolerate a much lower condenser water temperature. Does this mean that it is more efficient to provide the lower condenser water temperature? Not necessarily, since energy will be wasted running the cooling tower fans to achieve the lower temperature and energy will be wasted for the hot-gas bypass to bring the
condenser pressure up.<br><br>In my experience, the lower condenser water temperature is most often an issue on chiller start-up in cold weather. Some chillers will surge until the chiller warms the condenser water loop. Surging sounds like someone with advanced COPD breathing. <br>
<br>So, if Rohini's chillers are supplied with a nearly constant condenser water temperature, the EIR f(PLR&Lift) would not be critical.<br><br>Please see attached modeling data from Trane for a CVHE 450 ton chiller. All the data to build the various curves is shown. Note the difference in condenser bundle pressure drop for standard flow v. minimum flow. Much energy can be saved with a variable condenser water pumping strategy. <br>
<br>This data was used to calculate the loss of chiller efficiency due to reduced condenser water flow. In this particular project, I had three existing chillers. Total savings realized by the
variable condenser water scenario was 250,000 kWh/Year. The reduced chiller efficiency consumed 50,000 kWk per year so the net energy savings was 200,000 kWh/Year. Notice that the condenser water temperature varies in the data. That was based on the maximum heat rejection of the towers during the cooling season with a minimum of 65 degrees condenser water supply temperature. If I assumed a constant 78 degrees condenser water supply temperature the kW/Ton values would be much different.<br>
<br>It takes a little time to find the right person to provide this chiller data, but it is well worth it.<br><br>Paul<br><div><br></div><div style="font-family:times new roman,new york,times,serif;font-size:10pt"><br><div style="font-family:times new roman,new york,times,serif;font-size:12pt">
<font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight:bold">From:</span></b> Nick Caton
<<a href="mailto:ncaton@smithboucher.com" target="_blank">ncaton@smithboucher.com</a>><br><b><span style="font-weight:bold">To:</span></b> Paul Diglio <<a href="mailto:paul.diglio@sbcglobal.net" target="_blank">paul.diglio@sbcglobal.net</a>>; <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b><span style="font-weight:bold">Sent:</span></b> Fri, February 25, 2011 4:38:43 PM<br><b><span style="font-weight:bold">Subject:</span></b> RE: [Equest-users] using IPLV in eQuest<br></font><br>
<div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">Thanks very much for the informed response, Paul! </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">With all respect, I want to be sure I’m picking up the right
lessons here =):</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">Accepting the arbitrary nature of IPLV ratings, what I’ve
proposed for Rohini’s case is to define a curve that will utilize his model’s
unique annual part-load profile (tossing IPLV’s weightings out the window), and
would isolate the effects of PLR to make his equipment comparison.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">Am I correctly understanding that any comparative analysis that
isolates only the effects of part-load in comparing two chillers is pretty much
pointless? </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">I am not trying to make a case that lift, variable flows, and
their effects on capacity and efficiency are not important (and I have also
experienced responses all over the map from different manufacturers). I agree that
at least considering all of these in many cases is necessary when one wants to
model accurate behavior, particularly from a commissioning/servicing context. With
all other things being equal, I’m however proposing these factors shouldn’t be critical
if the specific goal is to determine <u>whether chiller A or chiller B fits a
model’s part load profile better</u>.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">So to clarify and make our bridges meet: Is it critical that
Rohini creates an EIR-fPLR&dT curve for his analysis (between two screw
chillers with everything else presumed identical), or is it fair to say this
may be overkill considering what he’s trying to achieve?</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">I for one will continue the good fight to obtain more solid
input data for my curves, sometimes I have to settle for “the best I can get”
with the people I’m supposed to be talking to, but your experiences are further
motivation to try to find the right people =)!</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">Thanks again,</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">~Nick</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"><img alt="cid:489575314@22072009-0ABB" width="119" height="37"></span><b><span style="font-size:11pt;color:rgb(45, 77, 94)"></span></b></p>
<p class="MsoNormal"><b><span style="font-size:11pt;color:rgb(45, 77, 94)"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11pt;color:rgb(45, 77, 94)">NICK CATON, E.I.T.</span></b><b><span style="color:rgb(45, 77, 94)"></span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:rgb(204, 153, 0)">PROJECT ENGINEER</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">Smith & Boucher Engineers</span><span style="font-size:7.5pt;color:rgb(204, 153, 0)"></span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">25501 west valley parkway</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">olathe ks 66061</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">direct <a href="tel:913%20344.0036" value="+19133440036" target="_blank">913 344.0036</a></span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">fax <a href="tel:913%20345.0617" value="+19133450617" target="_blank">913 345.0617</a></span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"><a rel="nofollow" title="blocked::www.smithboucher.com"><span style="font-size:10pt">www.smithboucher.com</span></a></span><u><span style="font-size:10pt;color:blue"> </span></u><span style="font-size:11pt;color:rgb(31, 73, 125)"></span></p>
</div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<div>
<div style="border-width:1pt medium medium;border-style:solid none none;border-color:rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color;padding:3pt 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10pt">From:</span></b><span style="font-size:10pt"> Paul Diglio
[mailto:<a href="mailto:paul.diglio@sbcglobal.net" target="_blank">paul.diglio@sbcglobal.net</a>] <br>
<b>Sent:</b> Friday, February 25, 2011 2:58 PM<br>
<b>To:</b> Nick Caton; <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Subject:</b> Re: [Equest-users] using IPLV in eQuest</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal"><span style="font-size:10pt">Nick:<br>
<br>
I come from a mechanical contracting and service background. Condenser
water temperature is a hotly debated item. Some manufacturers define a
very narrow range of acceptable condenser water temperature and others define a
very narrow range of the temperature difference between entering and leaving
condenser water temperature.<br>
<br>
During one investment-grade audit I performed recently, Trane told me that the
condenser water dt can be no <u>less</u> than 5 degrees for maximum efficiency
on the 650 ton CVHE chillers I was working with. The water temperature
could be anywhere to 50-80 degrees. This machine had hot-gas bypass to
keep the head pressure up.<br>
<br>
Other chillers that I have overhauled require a very narrow band of condenser
water temperature, such as 75-78 degrees supply temperature. So modeling
a wide condenser water range does not make much sense to me since it is not a
real world application. The chillers I have worked on either have a tower
bypass loop or a hot gas bypass to keep the condensing pressure up where it
belongs. Energy is wasted when too cold a condenser water temperature is
specified.<br>
<br>
Other manufacturers say the colder the better.<br>
<br>
Specifying variable primary chilled water flow and variable condenser water
flow has a large impact on chiller efficiency. I ask the manufacturers to
provide me the kW/Ton for minimum flow, standard flow and maximum flow for the
evaporator and condenser bundles. A chiller that has an kW/Ton of .56 at
AHRI conditions can often have a 1.3 kW/Ton at minimum condenser flow (3
gpm/ton) at 30% load.<br>
<br>
The IPLV is really a useless rating for a real world application since it
assumes a certain percentage load a certain percentage of the time. It
all depends on the design of the system and the load profile. It is a
good rating to compare various chillers if they conform to the load
profile. I see more chillers that run in the 40-60% range 90% of the time
than I see chillers that match the IPLV conditions.<br>
<br>
During my investment-grade reviews with our local utility, the lift of the
chiller is always an important consideration.<br>
<br>
There was an e-mail for someone, I believe York, that offered to model any
manufacturers chiller on this forum a few months ago. I have had good
luck getting the rep to provide the information that I requested as long as I
find the right person.<br>
<br>
Paul</span></p>
<div>
<p class="MsoNormal"><span style="font-size:10pt"> </span></p>
<div>
<div class="MsoNormal" style="text-align:center" align="center"><span style="font-size:10pt">
<hr align="center" width="100%" size="1">
</span></div>
<p class="MsoNormal" style="margin-bottom:12pt"><b><span style="font-size:10pt">From:</span></b><span style="font-size:10pt"> Nick Caton <<a href="mailto:ncaton@smithboucher.com" target="_blank">ncaton@smithboucher.com</a>><br>
<b>To:</b> Paul Diglio <<a href="mailto:paul.diglio@sbcglobal.net" target="_blank">paul.diglio@sbcglobal.net</a>>;
<a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Sent:</b> Fri, February 25, 2011 2:50:44 PM<br>
<b>Subject:</b> RE: [Equest-users] using IPLV in eQuest</span></p>
<div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">Paul, I may not have been crystal-clear, but if someone is
merely making a comparative analysis between two screw chillers, aren’t the
relative effects of varying lift between the two chillers negligible? My
general understanding is that lift is a more critical variable when comparing
VSD centrifugal chillers… This is why I suggested a simpler EIR-fPLR
curve would be sufficient in lieu of an EIR-fPLR&dT – I was trying to
simplify Rohini’s comparative analysis.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">I’d agree that an EIR-fPLR&dT curve would be more precise
and more appropriate if the goal is to better match the chiller behavior (and
creating custom CAP-FT and EIR-FT would be even better), but I was thinking
this would require an unnecessary amount of extra work for Rohini’s comparative
purpose.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">My “suggested information to request” below for constructing
EIR-fPLR&dT curves is based on my past experience with limitations of my
local manf. rep’s software – they need to set certain items constant to get the
numbers to crunch… Have you had luck collecting PLR runs where the
evaporator and/or condenser temp was allowed to float? I’ve picked up
through the lists that a better way to skin the cat may be to approach the
chiller controls reps where they may exist, as they may have more flexible
software…</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">I throw this disclaimer out sometimes: I certainly haven’t
been doing this for decades! If I’m misunderstanding something, I very
much welcome corrections ;). </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">Thanks,</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">~Nick</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"><img alt="cid:489575314@22072009-0ABB" border="0" width="119" height="37"></span></p>
<p class="MsoNormal"><b><span style="font-size:11pt;color:rgb(45, 77, 94)"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11pt;color:rgb(45, 77, 94)">NICK CATON, E.I.T.</span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:rgb(204, 153, 0)">PROJECT ENGINEER</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">Smith & Boucher Engineers</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">25501 west valley parkway</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">olathe ks 66061</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">direct <a href="tel:913%20344.0036" value="+19133440036" target="_blank">913 344.0036</a></span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">fax <a href="tel:913%20345.0617" value="+19133450617" target="_blank">913 345.0617</a></span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(31, 73, 125)"><a href="http://www.smithboucher.com" target="_blank">www.smithboucher.com</a></span><u><span style="font-size:10pt;color:blue"> </span></u></p>
</div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<div>
<div style="border-width:1pt medium medium;border-style:solid none none;border-color:windowtext -moz-use-text-color -moz-use-text-color;padding:3pt 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10pt">From:</span></b><span style="font-size:10pt"> Paul Diglio
[mailto:<a href="mailto:paul.diglio@sbcglobal.net" target="_blank">paul.diglio@sbcglobal.net</a>] <br>
<b>Sent:</b> Friday, February 25, 2011 12:44 PM<br>
<b>To:</b> Nick Caton; James Waechter; <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Subject:</b> Re: [Equest-users] using IPLV in eQuest</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<div>
<p class="MsoNormal" style="margin-bottom:12pt"><span style="font-size:10pt">Actually
what everyone is calling dt is more accurately referred to as lift. It is
the difference between the saturated evaporating temperature and the saturated
condensing temperature, which is different than the condenser water temperature
and the evaporator water temperature.<br>
<br>
A more accurate curve can be built if you have the chiller manufacturer model
both these variables for you, rather than leaving the evaporator water
temperature constant and just varying the condenser water temperature.
Any change in the evaporator pressure will effect the condensing pressure and
any change in the condensing pressure will effect the evaporator pressure.</span></p>
<div>
<p class="MsoNormal"><span style="font-size:10pt">Paul</span></p>
<div>
<div class="MsoNormal" style="text-align:center" align="center"><span style="font-size:10pt">
<hr align="center" width="100%" size="1">
</span></div>
<p class="MsoNormal" style="margin-bottom:12pt"><b><span style="font-size:10pt">From:</span></b><span style="font-size:10pt"> Nick Caton <<a href="mailto:ncaton@smithboucher.com" target="_blank">ncaton@smithboucher.com</a>><br>
<b>To:</b> James Waechter <jamesw@McKinstry.com>;
<a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><br>
<b>Sent:</b> Fri, February 25, 2011 1:21:42 PM<br>
<b>Subject:</b> Re: [Equest-users] using IPLV in eQuest</span></p>
<div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">James et al,</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">Rohini will need to create performance curves to make this
particular comparison. Otherwise using the default curves will result in
identical part load performances.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"><span>The following is excerpted from the following (short)
recommended reading concerning what IPLV means: <a href="http://ashrae-cfl.org/2010/03/understanding-iplvnplv/" target="_blank">http://ashrae-cfl.org/2010/03/understanding-iplvnplv/</a></span></span></p>
<p style="margin-left:0.5in">IPLV (or NPLV) = 0.01A+0.42B+0.45C+0.12D</p>
<p style="margin-left:0.5in">Where:</p>
<p style="margin-left:0.5in">A = COP or EER @ 100% Load</p>
<p style="margin-left:0.5in">B = COP or EER @ 75% Load</p>
<p style="margin-left:0.5in">C = COP or EER @ 50% Load</p>
<p style="margin-left:0.5in">D = COP or EER @ 25% Load</p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">John is saying knowing only the IPLV and the 100% load condition
efficiency (variable ‘A,’ above) is not enough information to extrapolate the
IPLV curves to compare the two chillers. </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">For the exercise of comparing the two non-centrifugal chillers
of the same technology/type, I would just focus on making a custom EIR-FPLR
(not EIR-fPLR&dT) for each chiller, and use the library CAP-FT AND EIR-FT
curves. My understanding is the effects of temperature on capacity and
EIR outside of centrifugal VSD chillers is negligible. NOTE:
Whenever using any of the default library chiller performance curves, that
means you MUST normalize to and specify the chiller at ARI conditions – those
curves aren’t normalized to anything else.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">So! If you can find the IPLV A, B, C and D values for both
chillers’ curves, you could come up with your EIR-FPLR curve coefficients (<u>curve
type = quadratic or cubic</u>) using a curve-fit in excel… or alternatively
make eQuest figure the coefficients by entering those points as raw data.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">You may more easily just make your own curves, following John’s
advice and getting part load unloading curves (100%, 90%, 80%... etc) held at a
constant chilled & condenser temperature to match the ARI* conditions
(85CWT if this is water cooled) at which you’re specifying the chiller
capacity/EIR. Again, you could either go into excel, normalize the data
(review DOE2 help entry for EIR-FPLR), make a scatter chart, and get the
coefficients using a curve fit… or enter the data as raw points into eQuest and
the coefficients will be figured by eQuest… whatever makes more sense to you.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt">For
others and personal future reference…. If you are looking to make an <u>EIR-fPLR&dT</u>
curve (for centrifugal chillers or otherwise): Ask your rep instead for
multiple (minimum 3) part load unloading runs, holding the delivered chilled
water temp constant, and vary the condenser water temperature incrementally for
each run (i.e. 85, 75, 65). Choose a range of CWT’s that cover the
anticipated range to be encountered in the actual design. This will get you
enough data to have the minimum 3 delta-T’s represented in your part load data
points to build this curve correctly. You’ll be using eQuest “raw-data”
entry method to make it generate the coefficients.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt">~Nick</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)">* Rather than ARI conditions (85F CWT), you could be normalizing
to Design condition EIR/CAP, provided you’re making a full set of custom curves
in the same fashion.</span></p>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"><img alt="cid:489575314@22072009-0ABB" border="0" width="119" height="37"></span></p>
<p class="MsoNormal"><b><span style="font-size:11pt;color:rgb(45, 77, 94)"> </span></b></p>
<p class="MsoNormal"><b><span style="font-size:11pt;color:rgb(45, 77, 94)">NICK CATON, E.I.T.</span></b></p>
<p class="MsoNormal"><span style="font-size:7.5pt;color:rgb(204, 153, 0)">PROJECT ENGINEER</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">Smith & Boucher Engineers</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">25501 west valley parkway</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">olathe ks 66061</span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">direct <a href="tel:913%20344.0036" value="+19133440036" target="_blank">913 344.0036</a></span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(45, 77, 94)">fax <a href="tel:913%20345.0617" value="+19133450617" target="_blank">913 345.0617</a></span></p>
<p class="MsoNormal"><span style="font-size:10pt;color:rgb(31, 73, 125)"><a rel="nofollow" href="http://www.smithboucher.com" target="_blank">www.smithboucher.com</a></span><u><span style="font-size:10pt;color:blue"> </span></u></p>
</div>
<p class="MsoNormal"><span style="font-size:11pt;color:rgb(31, 73, 125)"> </span></p>
<div>
<div style="border-width:1pt medium medium;border-style:solid none none;border-color:windowtext -moz-use-text-color -moz-use-text-color;padding:3pt 0in 0in">
<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>James
Waechter<br>
<b>Sent:</b> Friday, February 25, 2011 10:55 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> Re: [Equest-users] using IPLV in eQuest</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<p class="MsoNormal"><span style="font-size:10pt">John,</span></p>
<p class="MsoNormal"><span style="font-size:10pt"> </span></p>
<p class="MsoNormal"><span style="font-size:10pt">If
the only parameter Rohini enters into the program is the full-load EIR – which
he said is the same for both chillers – how will eQuest know to bend the curves
differently for the two chiller options. It is my understanding that
program would use the same chiller efficiency curves for both machines even
though their IPLVs are different.</span></p>
<p class="MsoNormal"><span style="font-size:10pt"> </span></p>
<p class="MsoNormal"><span style="font-size:10pt">In
order to overcome this issue, are you saying Rohini should get chiller performance
data from each of the manufacturers and enter his own custom curves? I
recall there was a discussion on that topic a few months back.</span></p>
<p class="MsoNormal"><span style="font-size:10pt"> </span></p>
<p class="MsoNormal"><span style="font-size:10pt">Regards,</span></p>
<p class="MsoNormal"><span style="font-size:10pt">James
Waechter Jr., P.E., CEM, LEED A.P.<br>
Energy Engineer – Rocky Mountain Region<br>
p <a href="tel:303%20215%204062" value="+13032154062" target="_blank">303 215 4062</a> | m <a href="tel:727%20686%203248" value="+17276863248" target="_blank">727 686 3248</a></span></p>
<p class="MsoNormal"><b><span style="font-size:10pt">McKinstry</span></b><span style="font-size:10pt"><br>
Consulting | Construction | Energy | Facility Services</span></p>
<p class="MsoNormal"><span style="font-size:10pt"><a rel="nofollow" href="http://www.mckinstry.com/" target="_blank"><span style="color:windowtext">www.mckinstry.com</span></a>
</span></p>
<p class="MsoNormal"><span style="font-size:10pt"> </span></p>
<p class="MsoNormal"><span style="font-size:10pt"> </span></p>
<p class="MsoNormal"><span style="font-size:10pt"> </span></p>
<div>
<div style="border-width:1pt medium medium;border-style:solid none none;border-color:windowtext -moz-use-text-color -moz-use-text-color;padding:3pt 0in 0in">
<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>John Aulbach<br>
<b>Sent:</b> Friday, February 25, 2011 9:41 AM<br>
<b>To:</b> R B; eQUEST Users List<br>
<b>Subject:</b> Re: [Equest-users] using IPLV in eQuest</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<div>
<div>
<p class="MsoNormal">Rohini:</p>
</div>
<div>
<p class="MsoNormal"> </p>
</div>
<div>
<p class="MsoNormal">Won't happen. IPLV is a number which has one equation and 4
unknowns. Actually, three unknowns as you know the 100% point. You need a
manufacturer's curve run at 85F constant condenser water temperature. Let
eQuest do the curve bending after that. ARI curve won't work right.</p>
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<p class="MsoNormal"> </p>
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<p class="MsoNormal"> </p>
<p class="MsoNormal"><span style="color:rgb(31, 73, 125)">John
R. Aulbach, PE, CEM</span></p>
<p class="MsoNormal"><span style="color:rgb(31, 73, 125)">Senior
Energy Engineer</span></p>
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<div class="MsoNormal"><span style="color:rgb(23, 54, 93)">
<hr style="color:rgb(23, 54, 93)" align="left" width="30%" noshade size="2">
</span></div>
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<p class="MsoNormal"><b><span style="font-variant:small-caps;color:navy">Partner</span></b><b><span style="font-variant:small-caps;color:green"> </span></b><b><span style="font-variant:small-caps;color:rgb(0, 102, 0)">Energy</span></b></p>
<p class="MsoNormal"><span style="color:rgb(31, 73, 125)">1990
E. Grand Avenue, El Segundo, CA 90245<br>
W: <a href="tel:888-826-1216%2C%20X254" value="+18888261216" target="_blank">888-826-1216, X254</a>| D: <a href="tel:310-765-7295" value="+13107657295" target="_blank">310-765-7295</a> | F: <a href="tel:310-817-2745" value="+13108172745" target="_blank">310-817-2745</a></span></p>
<p class="MsoNormal"><a rel="nofollow" href="http://www.ptrenergy.com/" target="_blank"><span style="color:purple">www.ptrenergy.com</span></a><span style="color:rgb(31, 73, 125)"> </span><a rel="nofollow" href="mailto:%7C%20jaulbach@ptrenergy.com" target="_blank"><span>| jaulbach@ptrenergy.com</span></a></p>
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<div class="MsoNormal" style="text-align:center" align="center"><span style="font-size:10pt">
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<p class="MsoNormal" style="margin-bottom:12pt"><b><span style="font-size:10pt">From:</span></b><span style="font-size:10pt"> R B <<a href="mailto:slv3sat@gmail.com" target="_blank">slv3sat@gmail.com</a>><br>
<b>To:</b> eQUEST Users List <<a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a>><br>
<b>Sent:</b> Fri, February 25, 2011 7:25:18 AM<br>
<b>Subject:</b> [Equest-users] using IPLV in eQuest</span></p>
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<p class="MsoNormal">Hi All, </p>
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<p class="MsoNormal">I would like to compare two screw chillers with same full
load kW/ton and different IPLV kW/ton. I am using the full load number for the
EIR. Where can the IPLV number be used? Is there some way to scale the
performance curves to reflect different IPLV's?</p>
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<p class="MsoNormal">-Rohini</p>
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<p class="MsoNormal"> </p>
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