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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Oh boy! - It seems that there is some
confusion with my thoughts on Nick’s chiller curve posts from earlier.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>My experience has been that catalog and
online data for water chilling packages provides typical ARI Standard 550/590
data. This data is NOT sufficient to create custom curves in eQuest unless each
hour’s operating points never stray off of these curves (not likely). This is
why I suggest working with the Mechanical Engineer and the Vendor. As a
design/support community, I don’t believe this approach is a “bother” to either
one of these team members. The approach of an integrated design process has its
merits and the participation of the energy modeler is welcome throughout the
design process. I also recognize the time it takes vendors to provide this
data. Therefore, suggesting that, unless it is expected that the chiller will
be operating above its design point, this added data is not necessary for
accurate custom curves.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Also, I am not suggesting that equipment is
selected without sufficient capacity to serve the calculated loads of a
building/process. I was simply stating possible cases where performance
information for a chiller between design and maximum capacities may be needed.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>John<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><st1:PersonName w:st="on"><font size=1 color=gray
face=Arial><span style='font-size:8.5pt;font-family:Arial;color:gray'>John T.
Forester</span></font></st1:PersonName><font size=1 color=gray face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:gray'>, P.E., LEED AP,
Mechanical Design Engineer </span></font><strong><b><font size=1
color="#0000a0" face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:#0000A0'>I BVH Integrated Services I</span></font></b></strong><strong><b><font
size=1 color=black face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:black'> </span></font></b></strong><font size=1 color=gray face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:gray'>617.658.9008 tel </span></font><strong><b><font
size=1 color="#0000a0" face=Arial><span style='font-size:8.5pt;font-family:
Arial;color:#0000A0'>I</span></font></b></strong><strong><b><font size=1
color=gray face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:gray'> </span></font></b></strong><font size=1 color=gray face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:gray'>617.244.3753 fax</span></font><font
size=1 color="#0000a0" face=Arial><span style='font-size:8.5pt;font-family:
Arial;color:#0000A0'> <strong><b><font face=Arial><span style='font-family:
Arial'>I</span></font></b></strong></span></font><strong><b><font size=1
color=gray face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:gray'> </span></font></b></strong><font size=1 color=gray face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:gray'><U4:STREET u5:st="on"><U4:ADDRESS u5:st="on"><U1:STREET u2:st="on"><U6:STREET u7:st="on"><U6:ADDRESS u7:st="on"><U1:ADDRESS u2:st="on">One
Gateway Center Suite 506, <U4:STREET u5:st="on"><U4:ADDRESS u5:st="on"><U1:STREET u2:st="on"><U1:ADDRESS u2:st="on">Newton
MA 02458 </span></font><strong><b><font size=1 color="#0000a0" face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:#0000A0'>I <a
href="http://www.bvhis.com">www.bvhis.com</a> I Hartford ● New Haven ●
Boston</span></font></b></strong><font color=gray><span style='color:gray'><o:p></o:p></span></font></p>
</div>
<div>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Paul Diglio
[mailto:paul.diglio@sbcglobal.net] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, November 03, 2010
2:18 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Carol Gardner; <st1:PersonName
w:st="on">John T. Forester</st1:PersonName><br>
<b><span style='font-weight:bold'>Cc:</span></b> <st1:PersonName w:st="on">equest-users@lists.onebuilding.org</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Equest-users]
Chiller Curves (oh boy!)</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<div>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'>John:<br>
<br>
In my opinion one needs to get the chiller modeled by the factory as the
catalogs do not contain nearly enough information.<br>
<br>
See attached spreadsheet. The top portion was provided by Trane. It
models this chiller at Standard, Maximum and Minimum condenser water
flows. I performed the calculations in the red border.<br>
<br>
I needed to model this in Excel for a utility incentive. I was
implementing variable condenser water flow. The kW/Ton increases using a
variable flow sequence.<br>
<br>
My total kWh savings for varying the speed of the condenser pumps was
approximately 250,000. The chiller consumed approximately 50,000 kWh more
with minimum condenser water flow.<br>
<br>
Trane modeled this project several times for me, they had a self-interest
because I was contracting them to perform some board upgrades as part of the
energy efficiency project.<br>
<br>
Paul Diglio<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 face="Times New Roman"><span style='font-size:
10.0pt'><o:p> </o:p></span></font></p>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
<hr size=1 width="100%" align=center>
</span></font></div>
<p class=MsoNormal style='margin-bottom:12.0pt'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> Carol
Gardner <cmg750@gmail.com><br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">John
T. Forester</st1:PersonName> <JohnTF@bvhis.com><br>
<b><span style='font-weight:bold'>Cc:</span></b> "<st1:PersonName w:st="on">equest-users@lists.onebuilding.org</st1:PersonName>"
<<st1:PersonName w:st="on">equest-users@lists.onebuilding.org</st1:PersonName>><br>
<b><span style='font-weight:bold'>Sent:</span></b> Wed, November 3, 2010
1:54:35 PM<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Equest-users]
Chiller Curves (oh boy!)<br>
</span></font><br>
I agree with you, John, but have a couple of other thoughts to add. The first
is I have not met a mechanical engineer that does not select a chiller that is
capable of supplying all loads. In fact, they generally oversize a bit to
accommodate possible future loads. The only piece of equipment I have ever seen
selected at over 100% was a VRV system and that is because they actually work
better at 120% loading. The second is that you can generally get a catalog from
a manufacturer to have on your shelf that has technical information like how
the chiller unloads based on temperatures and what the efficiency is at part
load so you can look up the chiller you need info for and not need to bother
the ME or the vendor. If you can't get/don't want a hard copy, most of this
info is on line, just look for technical specifications.<br>
<br>
Best,<br>
<br>
Carol<o:p></o:p></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>On Wed, Nov 3, 2010 at 9:48 AM, <st1:PersonName w:st="on">John T.
Forester</st1:PersonName> <<a href="mailto:JohnTF@bvhis.com" target="_blank"
ymailto="mailto:JohnTF@bvhis.com">JohnTF@bvhis.com</a>> wrote:<o:p></o:p></span></font></p>
<div>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>Nick,</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>I think you’re on the right track. Below are some of my
thoughts on your conclusions. I hope the modeling community will set me
straight if I’m wrong here.</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<ol start=1 type=1>
<li class=MsoNormal style='color:navy;mso-margin-top-alt:auto;mso-margin-bottom-alt:
auto;mso-list:l0 level1 lfo1'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Getting multiple performance
runs from vendors that show part-load performance independent of the CW
and CHW temps can often be challenging. Adding the “maximum
capability” task to that for each of the conditions requires a pretty
detailed understanding of the selection software. I’d say if you can
get PLR data for 3-4 different CHW temps while holding the CW temps
constant at 85, 75, 65 (and sometimes lower) – you’re ahead of most modelers.
Working with the Mechanical Design Engineer and the vendor together has
been successful for me in the past.</span></font><o:p></o:p></li>
<li class=MsoNormal style='color:navy;mso-margin-top-alt:auto;mso-margin-bottom-alt:
auto;mso-list:l0 level1 lfo1'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Defining the chiller
capabilities at the “maximum” may only come into play if you expect your
model to overload the chiller above the specified design capacity (I’m
thinking building additions or process loads). At this point, this data
(or knowing what the default eQuest curves do in that range) would be
useful. Depending on your project, the time spent on developing
curves for PLR >1.0 may not be justified.</span></font><o:p></o:p></li>
<li class=MsoNormal style='color:navy;mso-margin-top-alt:auto;mso-margin-bottom-alt:
auto;mso-list:l0 level1 lfo1'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial'>If you don’t have “max” data
and don’t want eQuest to assume performance at a part-load ratio >1.0,
you can set the DESIGN-PLR to 1.0.</span></font><o:p></o:p></li>
<li class=MsoNormal style='color:navy;mso-margin-top-alt:auto;mso-margin-bottom-alt:
auto;mso-list:l0 level1 lfo1'><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Either way, you want your
curves to be normalized at whatever condition you specify (Design or
Rated) and you want to enter those values on the Basic Specifications tab.</span></font><o:p></o:p></li>
</ol>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>John</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><st1:PersonName
w:st="on"><font size=1 color=gray face=Arial><span style='font-size:8.5pt;
font-family:Arial;color:gray'>John T. Forester</span></font></st1:PersonName><font
size=1 color=gray face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:gray'>, P.E., LEED AP, Mechanical Design Engineer </span></font><b><font
size=1 color="#0000a0" face=Arial><span style='font-size:8.5pt;font-family:
Arial;color:#0000A0;font-weight:bold'>I BVH Integrated Services I</span></font></b><b><font
size=1 color=black face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:black;font-weight:bold'> </span></font></b><font size=1 color=gray
face=Arial><span style='font-size:8.5pt;font-family:Arial;color:gray'>617.658.9008
tel </span></font><b><font size=1 color="#0000a0" face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:#0000A0;font-weight:bold'>I</span></font></b><b><font
size=1 color=gray face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:gray;font-weight:bold'> </span></font></b><font size=1 color=gray
face=Arial><span style='font-size:8.5pt;font-family:Arial;color:gray'>617.244.3753
fax</span></font><font size=1 color="#0000a0" face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:#0000A0'> <b><span
style='font-weight:bold'>I</span></b></span></font><b><font size=1 color=gray
face=Arial><span style='font-size:8.5pt;font-family:Arial;color:gray;
font-weight:bold'> </span></font></b><font size=1 color=gray face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:gray'>One Gateway Center Suite
506, Newton MA 02458 </span></font><b><font size=1 color="#0000a0" face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:#0000A0;font-weight:bold'>I <a
href="http://www.bvhis.com" target="_blank">www.bvhis.com</a> I Hartford ●
New Haven ● Boston</span></font></b><o:p></o:p></p>
</div>
</div>
<div>
<p class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>size=2
width="100%" align=center tabindex=-1> <o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;font-weight:
bold'>From:</span></font></b><font size=2 face=Tahoma><span style='font-size:
10.0pt;font-family:Tahoma'> Nick Caton [mailto:<a
href="mailto:ncaton@smithboucher.com" target="_blank"
ymailto="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, November 03, 2010
12:06 PM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">John
T. Forester</st1:PersonName>; <a
href="mailto:equest-users@lists.onebuilding.org" target="_blank"
ymailto="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><o:p></o:p></span></font></p>
<div>
<div>
<p class=MsoNormal><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma'><br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [Equest-users]
Chiller Curves (oh boy!)<o:p></o:p></span></font></p>
</div>
</div>
</div>
<div>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>John,</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>The design/max ratio is exactly what I’m discussing
below when I say “DESIGN-PLR ratio,” so we’re definitely in the same ballpark
=).</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>I’d like to apply/paraphrase your advice to a few
conditions to be sure I’m getting it correctly: </span></font><o:p></o:p></p>
<p><font size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;
font-family:Calibri;color:#1F497D'>-</span></font><font size=1 color="#1f497d"><span
style='font-size:7.5pt;color:#1F497D'>
</span></font><font size=2 color="#1f497d" face=Calibri><span style='font-size:
11.0pt;font-family:Calibri;color:#1F497D'>If we create all 3 custom curves, and
normalize each to a point at maximum (not design) capacity, then the
design-to-max ratio (DESIGN-PLR) should be set to 1.00.</span></font><o:p></o:p></p>
<p><font size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;
font-family:Calibri;color:#1F497D'>-</span></font><font size=1 color="#1f497d"><span
style='font-size:7.5pt;color:#1F497D'>
</span></font><font size=2 color="#1f497d" face=Calibri><span style='font-size:
11.0pt;font-family:Calibri;color:#1F497D'>If we create <u>only</u> the part
load efficiency curve (EIR-FPLR or EIR-FPLR&dT), and wish to use the
library defaults for EIR-FT and CAP-FT, then we should normalize this curve’s
data points to ARI conditions (as that’s what the library curves are normalized
to, per James’s email – I think I’ve read this somewhere also), specify an ARI
capacity, EIR and conditions on the basic specifications tab, and enter a
DESIGN-PLR of [ARI capacity/maximum capacity (for the same conditions)].</span></font><o:p></o:p></p>
<p><font size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;
font-family:Calibri;color:#1F497D'>-</span></font><font size=1 color="#1f497d"><span
style='font-size:7.5pt;color:#1F497D'>
</span></font><font size=2 color="#1f497d" face=Calibri><span style='font-size:
11.0pt;font-family:Calibri;color:#1F497D'>If we create all 3 custom curves, and
try to normalize each to either ARI or design conditions, then we should
specify capacity, EIR, CHWT, CWT and condenser GPM corresponding to either the
ARI or design conditions of that normalizing point. In that case, we also
specify a DESIGN-PLR using either the ARI or design capacity divided by the
maximum capacity for the same conditions.</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><u><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>Profound (to me) Conclusion</span></font></u><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>: In <u>No</u> instance should we <u>Ever</u>
attempt creating custom curves and NOT have at least one run from our
manufacturer telling us what the maximum (not design) capacity is for the
normalizing point. This conclusion would only apply to centrifugal
chillers only.</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>Does this all sound right?</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>~Nick</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>James, </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>Yeah, if all the part load data you received held the
same CHWT and CWT equal, you might be able to make your part-load curve if it
could have been a quadratic EIR-FPLR curve (like a reciprocating chiller), but
not a bi-quadratic EIR-FPLR&dT (as with my centrifugal VSD chiller).
You definitely could not approach generating custom EIR-FT or CAP-FT
curves without varying condenser and chilled water temps. That exact
issue happened to me the first few times I tried to reign my chiller reps in
=). </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>This time, I convinced my rep to give me multiple part
load runs holding the CHWT constant and varying the CWT incrementally.
This let me build the bi-quadratic EIR-FPLR&dT curve as I had at
least three different dT’s represented in my part load data points. I
plotted the 3D curve in excel to check my work and darned if the generated
coefficients seem to be really accurate =)! It’s currently looking
like a bittersweet revelation however – the library curve for a water-cooled
centrifugal VSD chiller (see attached visualization) seems a LOT more generous
(more efficient) at low part loads than the one I’ve generated which matches my
rep’s data… I might share a visual of my custom curve for comparison once
I’m dead-sure it’s accurate – I’m trying to clarify a few things with my rep
right now.</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>~Nick</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'><img border=0 width=119 height=37 id="_x0000_i1026"
src="%20" alt="cid:489575314@22072009-0ABB"></span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 color="#2d4d5e" face="Stylus BT"><span style='font-size:11.0pt;
font-family:"Stylus BT";color:#2D4D5E;font-weight:bold'> </span></font></b><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 color="#2d4d5e" face="Stylus BT"><span style='font-size:11.0pt;
font-family:"Stylus BT";color:#2D4D5E;font-weight:bold'>NICK CATON, E.I.T.</span></font></b><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=1 color="#cc9900" face=Calibri><span style='font-size:7.5pt;font-family:
Calibri;color:#CC9900'>PROJECT ENGINEER</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E'>25501 west valley parkway</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><st1:City
w:st="on"><st1:place w:st="on"><font size=2 color="#2d4d5e" face=Calibri><span
style='font-size:10.0pt;font-family:Calibri;color:#2D4D5E'>olathe</span></font></st1:place></st1:City><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E'> ks 66061</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E'>direct 913 344.0036</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E'>fax 913 345.0617</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><i><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E;font-style:italic'>Check out our new web-site @ </span></font></i><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'><a href="http://www.smithboucher.com" target="_blank"
title="blocked::www.smithboucher.com"><font size=2><span style='font-size:10.0pt'>www.smithboucher.com</span></font></a></span></font><u><font
size=2 color=blue face=Calibri><span style='font-size:10.0pt;font-family:Calibri;
color:blue'> </span></font></u><o:p></o:p></p>
</div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;font-weight:
bold'>From:</span></font></b><font size=2 face=Tahoma><span style='font-size:
10.0pt;font-family:Tahoma'> <st1:PersonName w:st="on">John T. Forester</st1:PersonName>
[mailto:<a href="mailto:JohnTF@BVHis.com" target="_blank"
ymailto="mailto:JohnTF@BVHis.com">JohnTF@BVHis.com</a>] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, November 03, 2010
10:29 AM<br>
<b><span style='font-weight:bold'>To:</span></b> Nick Caton; <a
href="mailto:equest-users@lists.onebuilding.org" target="_blank"
ymailto="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br>
<b><span style='font-weight:bold'>Subject:</span></b> RE: [Equest-users]
Chiller Curves (oh boy!)</span></font><o:p></o:p></p>
</div>
</div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>Nick,</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>When defining a centrifugal chiller in eQuest, one of the items on
the Basic Specifications tab under the Design vs. Rated Conditions is a
Design/Max Cap ratio. By default, this is 92% for a water cooled
unit. I believe this gets at the discussion in the help pages that talks
about maximum capacity versus design capacity and how the chiller vendor will
spec a piece of equipment. Typically, vendors don’t often get asked (or
provide) what the “Maximum” capacity of a spec’d unit is. Therefore the
performance data that they provide are at “design conditions.”</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>If you change the chiller type to a reciprocating chiller, this
“Design/Max Cap” ratio is disabled and the default specified condition changes
from “Design Conditions” to “Rated Conditions.” This suggests that there
is little “extra” capacity when a selection is done for that type of chiller.</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>If you do get “maximum capacity” data and create curves from that
data, you will want to change the Design/Max Cap ratio to 1.0 so eQuest knows
that there isn’t any spare capacity at the chiller. Also if the data
points you are using to normalize your curves are different than the design
conditions for your energy model, you will want to change the “Chiller
Specified at” value to “Rated Conditions” and enter the rated conditions for
CHW temp, CW temp and CW gpm/ton to match your normalized curves.</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>Hope this helps,</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>John</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'> </span></font><o:p></o:p></p>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><st1:PersonName
w:st="on"><font size=1 color=gray face=Arial><span style='font-size:8.5pt;
font-family:Arial;color:gray'>John T. Forester</span></font></st1:PersonName><font
size=1 color=gray face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:gray'>, P.E., LEED AP, Mechanical Design Engineer </span></font><b><font
size=1 color="#0000a0" face=Arial><span style='font-size:8.5pt;font-family:
Arial;color:#0000A0;font-weight:bold'>I BVH Integrated Services I</span></font></b><b><font
size=1 color=black face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:black;font-weight:bold'> </span></font></b><font size=1 color=gray
face=Arial><span style='font-size:8.5pt;font-family:Arial;color:gray'>617.658.9008
tel </span></font><b><font size=1 color="#0000a0" face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:#0000A0;font-weight:bold'>I</span></font></b><b><font
size=1 color=gray face=Arial><span style='font-size:8.5pt;font-family:Arial;
color:gray;font-weight:bold'> </span></font></b><font size=1 color=gray
face=Arial><span style='font-size:8.5pt;font-family:Arial;color:gray'>617.244.3753
fax</span></font><font size=1 color="#0000a0" face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:#0000A0'> <b><span
style='font-weight:bold'>I</span></b></span></font><b><font size=1 color=gray
face=Arial><span style='font-size:8.5pt;font-family:Arial;color:gray;
font-weight:bold'> </span></font></b><font size=1 color=gray face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:gray'>One Gateway Center Suite
506, Newton MA 02458 </span></font><b><font size=1 color="#0000a0" face=Arial><span
style='font-size:8.5pt;font-family:Arial;color:#0000A0;font-weight:bold'>I <a
href="http://www.bvhis.com" target="_blank">www.bvhis.com</a> I Hartford ●
New Haven ● Boston</span></font></b><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal align=center style='mso-margin-top-alt:auto;mso-margin-bottom-alt:
auto;text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><hr size=2 width="100%" align=center
tabindex=-1> <o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;font-weight:
bold'>From:</span></font></b><font size=2 face=Tahoma><span style='font-size:
10.0pt;font-family:Tahoma'> <a
href="mailto:equest-users-bounces@lists.onebuilding.org" target="_blank"
ymailto="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a>
[mailto:<a href="mailto:equest-users-bounces@lists.onebuilding.org"
target="_blank" ymailto="mailto:equest-users-bounces@lists.onebuilding.org">equest-users-bounces@lists.onebuilding.org</a>]
<b><span style='font-weight:bold'>On Behalf Of </span></b>Nick Caton<br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, November 03, 2010
11:03 AM<br>
<b><span style='font-weight:bold'>To:</span></b> Carol Gardner; <a
href="mailto:equest-users@lists.onebuilding.org" target="_blank"
ymailto="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Equest-users]
Chiller Curves (oh boy!)</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>Thanks for the response Carol!</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>That 120% load case is what I’m getting at – let me try
to explain a little further:</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>In the DOE2 help files, the vocabulary for centrifugal
chillers is “design capacity” and “maximum capacity,” where “design” means the
capacity at the rated or designed conditions (at which you define / specify
your chiller), and “maximum” means the capacity the chiller is really capable
of under the same conditions if it runs balls-out (maximum power to the
refrigerant drive).</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>The help file excerpt I copied below with the red line
is pretty explicitly telling us to normalize the part load values to the <u>maximum</u>
capacity for centrifugal chillers. I’ve highlighted a second line for
clarity. The EDR guidelines I linked below are saying you can instead
normalize to the <u>design</u> capacity for the EIR-PLR curve if that’s all
your field measurements or manufacturer rep can provide.</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>I’m asking – are both approaches right? </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>My first and second questions are kinda tied together…
How would choosing to normalize to either the maximum or design conditions
affect how we should handle the DESIGN-PLR ratio, if at all?</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'>~Nick.</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'><img border=0 width=119 height=37 id="_x0000_i1027"
src="%20" alt="cid:489575314@22072009-0ABB"></span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 color="#2d4d5e" face="Stylus BT"><span style='font-size:11.0pt;
font-family:"Stylus BT";color:#2D4D5E;font-weight:bold'> </span></font></b><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 color="#2d4d5e" face="Stylus BT"><span style='font-size:11.0pt;
font-family:"Stylus BT";color:#2D4D5E;font-weight:bold'>NICK CATON, E.I.T.</span></font></b><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=1 color="#cc9900" face=Calibri><span style='font-size:7.5pt;font-family:
Calibri;color:#CC9900'>PROJECT ENGINEER</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E'>25501 west valley parkway</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><st1:City
w:st="on"><st1:place w:st="on"><font size=2 color="#2d4d5e" face=Calibri><span
style='font-size:10.0pt;font-family:Calibri;color:#2D4D5E'>olathe</span></font></st1:place></st1:City><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E'> ks 66061</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E'>direct 913 344.0036</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E'>fax 913 345.0617</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><i><font
size=2 color="#2d4d5e" face=Calibri><span style='font-size:10.0pt;font-family:
Calibri;color:#2D4D5E;font-style:italic'>Check out our new web-site @ </span></font></i><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'><a href="http://www.smithboucher.com" target="_blank"
title="blocked::www.smithboucher.com"><font size=2><span style='font-size:10.0pt'>www.smithboucher.com</span></font></a></span></font><u><font
size=2 color=blue face=Calibri><span style='font-size:10.0pt;font-family:Calibri;
color:blue'> </span></font></u><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#1f497d" face=Calibri><span style='font-size:11.0pt;font-family:
Calibri;color:#1F497D'> </span></font><o:p></o:p></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;font-weight:
bold'>From:</span></font></b><font size=2 face=Tahoma><span style='font-size:
10.0pt;font-family:Tahoma'> Carol Gardner [mailto:<a
href="mailto:cmg750@gmail.com" target="_blank" ymailto="mailto:cmg750@gmail.com">cmg750@gmail.com</a>]
<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, November 02, 2010
10:04 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Nick Caton<br>
<b><span style='font-weight:bold'>Cc:</span></b> <a
href="mailto:equest-users@lists.onebuilding.org" target="_blank"
ymailto="mailto:equest-users@lists.onebuilding.org">equest-users@lists.onebuilding.org</a><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [Equest-users]
Chiller Curves (oh boy!)</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'>Let me take a
crack at this. If by design capacity you mean the chiller running at 100% load,
you would create the curve(s) by normalizing around your ARI design conditions
i.e. the PLR curve would be 1.0 at this point, call it ARI Cap and the other
points would be 90% Cap/ARI Cap, 80% Cap/ARI Cap, etc. The same would go for
your temp curves. If, however, your chiller is operating at 120%, or some such
other level, I would normalize the curve around the ARI design conditions of
the chiller at 120%. I had to do this for a VRV hp that was selected at the
120% design condition.<br>
<br>
I find this from the DOE2 manual the most helpful:<o:p></o:p></span></font></p>
<div style='border-top:solid #999999 1.0pt;border-left:none;border-bottom:solid #999999 1.0pt;
border-right:none;padding:0in 0in 0in 0in'>
<div>
<div>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
</div>
<div>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'><a
href="http://volume2dictionary.htm" target="_blank">Volume 2: Dictionary</a>
> <a href="http://hvaccomponents.htm" target="_blank">HVAC Components</a>
> <a href="http://curvefit.htm" target="_blank"><font color=white><span
style='background-attachment:scroll;background-position-x:0%;background-position-y:
0%'><span style='color:white;background:#316AC5'>CURVE</span></span></font>-<font
color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>FIT</span></span></font></a>
> <a href="http://inputtypedata.htm" target="_blank">INPUT-TYPE = DATA</a><o:p></o:p></span></font></p>
</div>
<h5><b><font size=2 face="Times New Roman"><span style='font-size:10.0pt'>INDEPENDENT-2<o:p></o:p></span></font></b></h5>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>Used for
all <font color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>curves</span></span></font>
having two independent variables. A list of up to twenty values of the second
independent variable. The number of values should be the same as for DEPENDENT.<o:p></o:p></span></font></p>
<p><b><font size=3 face=Arial><span style='font-size:12.0pt;font-family:Arial;
font-weight:bold'>Example 1</span></font></b>: defining a <font color=white><span
style='background-attachment:scroll;background-position-x:0%;background-position-y:
0%'><span style='color:white;background:#316AC5'>curve</span></span></font> by
inputting a set of data points.<o:p></o:p></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>A
packaged system (PZS) has cooling performance significantly different from that
used in the default model. The manufacturer lists the data shown in Table
46, for cooling capacity, at 2000 cfm design air flow rate, as a function of
outside dry-bulb temperature and entering wet-bulb temperature.<o:p></o:p></span></font></p>
<p><a name="12c12a536c514b6a__Ref490744859"></a><a
name="12c12a536c514b6a__Ref490744804"></a><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Table 46 Cooling capacity (kBtu/hr) vs.
temperature<o:p></o:p></span></font></p>
<div style='margin-top:2.0pt;margin-bottom:2.0pt'>
<div align=center>
<table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0
style='border-collapse:collapse'>
<tr>
<td width=96 rowspan=2 valign=top bgcolor=aqua style='width:1.0in;border:
solid windowtext 1.0pt;background:aqua;padding:0in 5.4pt 0in 5.4pt;
background-attachment:scroll;background-position-x:0%;background-position-y:
0%'>
<p align=center style='margin-top:0in;text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>Outside<br>
Dry-bulb</span></font></b><o:p></o:p></p>
</td>
<td width=288 colspan=3 valign=top bgcolor=aqua style='width:3.0in;
border-top:solid windowtext 1.0pt;border-left:none;border-bottom:none;
border-right:solid windowtext 1.0pt;background:aqua;padding:0in 5.4pt 0in 5.4pt;
background-attachment:scroll;background-position-x:0%;background-position-y:
0%'>
<p align=center style='text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>Entering
Wet-bulb</span></font></b><o:p></o:p></p>
</td>
</tr>
<tr>
<td width=96 valign=top bgcolor=aqua style='width:1.0in;border:none;
border-bottom:solid windowtext 1.0pt;background:aqua;padding:0in 5.4pt 0in 5.4pt;
background-attachment:scroll;background-position-x:0%;background-position-y:
0%'>
<p align=center style='text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>72F</span></font></b><o:p></o:p></p>
</td>
<td width=96 valign=top bgcolor=aqua style='width:1.0in;border:none;
border-bottom:solid windowtext 1.0pt;background:aqua;padding:0in 5.4pt 0in 5.4pt;
background-attachment:scroll;background-position-x:0%;background-position-y:
0%'>
<p align=center style='text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>67F</span></font></b><o:p></o:p></p>
</td>
<td width=96 valign=top bgcolor=aqua style='width:1.0in;border-top:none;
border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
background:aqua;padding:0in 5.4pt 0in 5.4pt;background-attachment:scroll;
background-position-x:0%;background-position-y:0%'>
<p align=center style='text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>62F</span></font></b><o:p></o:p></p>
</td>
</tr>
<tr>
<td width=96 valign=top style='width:1.0in;border-top:none;border-left:solid windowtext 1.0pt;
border-bottom:none;border-right:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>85F<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>69<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>65<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-right:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>60<o:p></o:p></span></font></p>
</td>
</tr>
<tr>
<td width=96 valign=top style='width:1.0in;border-top:none;border-left:solid windowtext 1.0pt;
border-bottom:none;border-right:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>95F<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>68<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>63 (ARI)<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-right:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>57<o:p></o:p></span></font></p>
</td>
</tr>
<tr>
<td width=96 valign=top style='width:1.0in;border-top:none;border-left:solid windowtext 1.0pt;
border-bottom:none;border-right:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>105F<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>65<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>60<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-right:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>53<o:p></o:p></span></font></p>
</td>
</tr>
<tr>
<td width=96 valign=top style='width:1.0in;border:solid windowtext 1.0pt;
border-top:none;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>115F<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-bottom:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>62<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-bottom:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>55<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border-top:none;border-left:none;
border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='margin-bottom:0in;margin-bottom:.0001pt;text-align:
center'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>49<o:p></o:p></span></font></p>
</td>
</tr>
</table>
</div>
</div>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>In this
example the independent variables are the entering wet-bulb temperature and the
outside dry-bulb temperature. Because there are two independent variables and
they have units of temperature, we input a <font color=white><span
style='background-attachment:scroll;background-position-x:0%;background-position-y:
0%'><span style='color:white;background:#316AC5'>curve</span></span></font> of
TYPE BI-QUADRATIC-T using the given data points. The dependent variable is not
the cooling capacity listed in the table but rather the cooling capacity
divided by the cooling capacity at the ARI rating point (95 F outside dry-bulb
and 67 F entering wet-bulb). In other words, the capacities should be
normalized to the ARI rating point., as shown in Table 47<o:p></o:p></span></font></p>
<p><a name="12c12a536c514b6a__Ref490745029"><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Table </span></font></a>47 Normalized capacity
vs. temperature<o:p></o:p></p>
<div style='margin-top:2.0pt;margin-bottom:2.0pt'>
<div align=center>
<table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0
style='border-collapse:collapse'>
<tr>
<td width=96 rowspan=2 valign=top bgcolor=aqua style='width:1.0in;border:
solid windowtext 1.0pt;background:aqua;padding:0in 5.4pt 0in 5.4pt;
background-attachment:scroll;background-position-x:0%;background-position-y:
0%'>
<p align=center style='margin-top:0in;text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>Outside<br>
Dry-bulb</span></font></b><o:p></o:p></p>
</td>
<td width=288 colspan=3 valign=top bgcolor=aqua style='width:3.0in;
border-top:solid windowtext 1.0pt;border-left:none;border-bottom:none;
border-right:solid windowtext 1.0pt;background:aqua;padding:0in 5.4pt 0in 5.4pt;
background-attachment:scroll;background-position-x:0%;background-position-y:
0%'>
<p align=center style='text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>Entering
Wet-bulb</span></font></b><o:p></o:p></p>
</td>
</tr>
<tr>
<td width=96 valign=top bgcolor=aqua style='width:1.0in;border:none;
border-bottom:solid windowtext 1.0pt;background:aqua;padding:0in 5.4pt 0in 5.4pt;
background-attachment:scroll;background-position-x:0%;background-position-y:
0%'>
<p align=center style='text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>72F</span></font></b><o:p></o:p></p>
</td>
<td width=96 valign=top bgcolor=aqua style='width:1.0in;border:none;
border-bottom:solid windowtext 1.0pt;background:aqua;padding:0in 5.4pt 0in 5.4pt;
background-attachment:scroll;background-position-x:0%;background-position-y:
0%'>
<p align=center style='text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>67F</span></font></b><o:p></o:p></p>
</td>
<td width=96 valign=top bgcolor=aqua style='width:1.0in;border-top:none;
border-left:none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
background:aqua;padding:0in 5.4pt 0in 5.4pt;background-attachment:scroll;
background-position-x:0%;background-position-y:0%'>
<p align=center style='text-align:center'><b><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-weight:bold'>62F</span></font></b><o:p></o:p></p>
</td>
</tr>
<tr>
<td width=96 valign=top style='width:1.0in;border-top:none;border-left:solid windowtext 1.0pt;
border-bottom:none;border-right:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>85F<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>1.095<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>1.032<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-right:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>0.952<o:p></o:p></span></font></p>
</td>
</tr>
<tr>
<td width=96 valign=top style='width:1.0in;border-top:none;border-left:solid windowtext 1.0pt;
border-bottom:none;border-right:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>95F<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>1.079<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>1.0 (ARI)<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-right:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>0.905<o:p></o:p></span></font></p>
</td>
</tr>
<tr>
<td width=96 valign=top style='width:1.0in;border-top:none;border-left:solid windowtext 1.0pt;
border-bottom:none;border-right:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>105F<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>1.032<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>0.952<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-right:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>0.841<o:p></o:p></span></font></p>
</td>
</tr>
<tr>
<td width=96 valign=top style='width:1.0in;border:solid windowtext 1.0pt;
border-top:none;padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>115F<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-bottom:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>0.984<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border:none;border-bottom:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='text-align:center'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>0.873<o:p></o:p></span></font></p>
</td>
<td width=96 valign=top style='width:1.0in;border-top:none;border-left:none;
border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt;
padding:0in 5.4pt 0in 5.4pt'>
<p align=center style='margin-bottom:0in;margin-bottom:.0001pt;text-align:
center'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>0.778<o:p></o:p></span></font></p>
</td>
</tr>
</table>
</div>
</div>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>The <font
color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>CURVE</span></span></font>-<font
color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>FIT</span></span></font>
input will look like the following:<o:p></o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>CAP-<font
color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>CURVE</span></span></font>-1
= <font color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>CURVE</span></span></font>-<font
color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>FIT</span></span></font><br>
TYPE
= BI-QUADRATIC-T<br>
INPUT-TYPE = DATA<br>
DEPENDENT =
(1.000,1.079,0.905,1.032,0.952,0.841,<br>
0.984,0.873,0.778,1.095,1.032,0.952) ..<br>
IN-TEMP1 =
( 67, 72, 62, 72,
67, 62,<br>
72, 67, 62,
72, 67, 62) ..<br>
IN-TEMP2 =
( 95, 95, 95, 105, 105,
105,<br>
115, 115, 115,
85 85, 85) ..<o:p></o:p></span></font></p>
<p><b><font size=3 face=Arial><span style='font-size:12.0pt;font-family:Arial;
font-weight:bold'>Example 2:</span></font></b> Defining a <font color=white><span
style='background-attachment:scroll;background-position-x:0%;background-position-y:
0%'><span style='color:white;background:#316AC5'>curve</span></span></font> by
inputting coefficients<o:p></o:p></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>We want a
furnace to have a constant efficiency as a function of part load. To do this we
must replace the default FURNACE-HIR-FPLR with a <font color=white><span
style='background-attachment:scroll;background-position-x:0%;background-position-y:
0%'><span style='color:white;background:#316AC5'>curve</span></span></font> that
will give a constant efficiency. The <font color=white><span style='background-attachment:
scroll;background-position-x:0%;background-position-y:0%'><span
style='color:white;background:#316AC5'>curve</span></span></font> TYPE is
QUADRATIC in the part load ratio (PLR). PLR correction <font color=white><span
style='background-attachment:scroll;background-position-x:0%;background-position-y:
0%'><span style='color:white;background:#316AC5'>curves</span></span></font>
are always multiplied by the unit capacity, not the load, to obtain the energy
(fuel or electricity) use. Thus the <font color=white><span style='background-attachment:
scroll;background-position-x:0%;background-position-y:0%'><span
style='color:white;background:#316AC5'>curve</span></span></font> we want is:
0.0 + 1.0*PLR + 0.0*PLR*PLR. The input will look like:<o:p></o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>New-Furnace-HIR-fPLR
= <font color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>CURVE</span></span></font>-<font
color=white><span style='background-attachment:scroll;background-position-x:
0%;background-position-y:0%'><span style='color:white;background:#316AC5'>FIT</span></span></font><br>
TYPE
= QUADRATIC<br>
INPUT-TYPE = COEFFICIENTS<br>
COEFFICIENTS = (0.0,1.0,0.0) ..<o:p></o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>Then in
the SYSTEM command we include:<o:p></o:p></span></font></p>
<p><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>
FURNACE-HIR-FPLR = New-Furnace-HIR-fPLR<o:p></o:p></span></font></p>
</div>
<p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'> <o:p></o:p></span></font></p>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'>On Tue, Nov 2,
2010 at 3:21 PM, Nick Caton <<a href="mailto:ncaton@smithboucher.com"
target="_blank" ymailto="mailto:ncaton@smithboucher.com">ncaton@smithboucher.com</a>>
wrote:<o:p></o:p></span></font></p>
<div>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 color="#1f497d" face="Times New Roman"><span style='font-size:12.0pt;
color:#1F497D'>Hi everyone!</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 color="#1f497d" face="Times New Roman"><span style='font-size:12.0pt;
color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 color="#1f497d" face="Times New Roman"><span style='font-size:12.0pt;
color:#1F497D'>I think I have <u>finally</u> wrapped my mind completely around custom
chiller performance curves for a centrifugal VSD chiller. I’ve got a few
specific questions now that I’m on the other side of the fence:</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 color="#1f497d" face="Times New Roman"><span style='font-size:12.0pt;
color:#1F497D'> </span></font><o:p></o:p></p>
<p><font size=3 color="#1f497d" face="Times New Roman"><span style='font-size:
12.0pt;color:#1F497D'>1.</span></font><font size=1 color="#1f497d"><span
style='font-size:7.0pt;color:#1F497D'> </span></font><font
color="#1f497d"><span style='color:#1F497D'>Is it necessary for the data points
of a part load efficiency curve (EIR-FPLR&dT in my case) to originate from
data with a 1.0 (100%) PLR ratio corresponding to a maximum vs. a design load
capacity? From what I gather in <a
href="http://www.energydesignresources.com/Portals/0/documents/DesignGuidelines/EDR_DesignGuidelines_%20HVAC_Simulation.pdf"
target="_blank">the EDR reference</a> (re: “Method 2” on PDF page 32/65), this
curve can be generated using part-load readings assuming a <u>design</u>
capacity at the 100% loading mark… but the DOE2 help entry for “EIR-FPLR” seems
to suggest otherwise (copied below – see highlighted line).</span></font><o:p></o:p></p>
<p><font size=3 color="#1f497d" face="Times New Roman"><span style='font-size:
12.0pt;color:#1F497D'>2.</span></font><font size=1 color="#1f497d"><span
style='font-size:7.0pt;color:#1F497D'> </span></font><font
color="#1f497d"><span style='color:#1F497D'>If the above part load efficiency
curve is created based on data where the 100% loading point corresponds to the
maximum (not design) capacity, should “DESIGN-PLR” (the ratio of design to
maximum capacity) be set to 1.00 and the capacity of the chiller be specified
at its maximum (not design) for the design/rated conditions? As I write
this question it sounds like I’m chasing my tail – someone straighten me out
=)!</span></font><o:p></o:p></p>
<p><font size=3 color="#1f497d" face="Times New Roman"><span style='font-size:
12.0pt;color:#1F497D'>3.</span></font><font size=1 color="#1f497d"><span
style='font-size:7.0pt;color:#1F497D'> </span></font><font
color="#1f497d"><span style='color:#1F497D'>When you veterans finish a project
with sets of custom performance curves, do you have any suggestions for a
naming scheme for future reference/re-use? I’m currently thinking to keep
the curves grouped in an .inp snippet I for importing along with an equipment
cutsheet… but I’m certain I’ll forget the all the details as quickly as humanly
possible when this project is behind me…</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 color="#1f497d" face="Times New Roman"><span style='font-size:12.0pt;
color:#1F497D'> </span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:.25in'><font size=3 color="#1f497d" face="Times New Roman"><span
style='font-size:12.0pt;color:#1F497D'> ~Nick</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 color="#1f497d" face="Times New Roman"><span style='font-size:12.0pt;
color:#1F497D'> </span></font><o:p></o:p></p>
<div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 color="#1f497d" face="Times New Roman"><span style='font-size:12.0pt;
color:#1F497D'><img border=0 width=119 height=37 id="_x0000_i1028" src="%20"
alt="cid:489575314@22072009-0ABB"></span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=3 color="#2d4d5e" face="Times New Roman"><span style='font-size:12.0pt;
color:#2D4D5E;font-weight:bold'> </span></font></b><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=3 color="#2d4d5e" face="Times New Roman"><span style='font-size:12.0pt;
color:#2D4D5E;font-weight:bold'>NICK CATON, E.I.T.</span></font></b><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=1 color="#cc9900" face="Times New Roman"><span style='font-size:7.5pt;
color:#CC9900'>PROJECT ENGINEER</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face="Times New Roman"><span style='font-size:10.0pt;
color:#2D4D5E'>25501 west valley parkway</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><st1:City
w:st="on"><st1:place w:st="on"><font size=2 color="#2d4d5e"
face="Times New Roman"><span style='font-size:10.0pt;color:#2D4D5E'>olathe</span></font></st1:place></st1:City><font
size=2 color="#2d4d5e"><span style='font-size:10.0pt;color:#2D4D5E'> ks 66061</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face="Times New Roman"><span style='font-size:10.0pt;
color:#2D4D5E'>direct 913 344.0036</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=2 color="#2d4d5e" face="Times New Roman"><span style='font-size:10.0pt;
color:#2D4D5E'>fax 913 345.0617</span></font><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><i><font
size=2 color="#2d4d5e" face="Times New Roman"><span style='font-size:10.0pt;
color:#2D4D5E;font-style:italic'>Check out our new web-site @ </span></font></i><font
color="#1f497d"><span style='color:#1F497D'><a
href="http://www.smithboucher.com" target="_blank"
title="blocked::www.smithboucher.com"><font size=2><span style='font-size:10.0pt'>www.smithboucher.com</span></font></a></span></font><u><font
size=2 color=blue><span style='font-size:10.0pt;color:blue'> </span></font></u><o:p></o:p></p>
</div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=2 face="Times New Roman"><span style='font-size:10.0pt;font-weight:bold'>EIR-FPLR</span></font></b><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'>Takes the U-name
of a curve that adjusts the electric input ratio as a function of<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:.5in'><font size=3 face=Symbol><span style='font-size:12.0pt;
font-family:Symbol'>· </span></font><u>The part load ratio (PLR)</u> –
The PLR is defined as the ratio of the hourly load to the hourly
capacity; Load / Cap<sub>hour</sub><o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:.5in'><font size=3 face=Symbol><span style='font-size:12.0pt;
font-family:Symbol'>· </span></font><u>The evaporator/condenser dT</u> -
The temperature differential between the condenser and leaving chilled-water.
The meaning of the condenser temperature varies according to condenser
type. <o:p></o:p></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
margin-left:2.7pt'><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>For most chillers, the dT has a relatively small effect on part-load
performance. However, for variable-speed centrifugal chillers, the effect of dT
is as important as the PLR. This is because the pressure rise across the
impeller is proportional to the square of the impeller’s speed. Unless some
form on condenser temperature relief is employed to reduce the temperature (and
pressure) differential across the chiller at part load, the performance of a
variable-speed chiller may not be significantly different than that of a
constant-speed chiller.<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'>To model power
consumption as a function of the PLR only, use a CURVE-FIT of TYPE = QUADRATIC
or CUBIC. To model as a function of both PLR and dT, use a
BI-QUADRATIC-RATIO&DT curve. <b><font color=red><span style='color:red;
font-weight:bold'>The curve must be normalized to 1.0 at full load and the
rated temperature differential. </span></font></b><o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><b><font
size=3 color=red face="Times New Roman"><span style='font-size:12.0pt;
color:red;font-weight:bold'>Note that, for centrifugal chillers, ‘full load’ is
defined as the ‘maximum capacity’, not the ‘design capacity’.</span></font></b>
Refer to the DESIGN-PLR keyword for more information.<o:p></o:p></p>
<p style='margin-bottom:12.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'> <o:p></o:p></span></font></p>
</div>
</div>
<p class=MsoNormal style='mso-margin-top-alt:auto;margin-bottom:12.0pt'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'><br>
_______________________________________________<br>
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To unsubscribe from this mailing list send a blank message to <a
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</div>
<p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'><br>
<br clear=all>
<br>
-- <br>
Carol Gardner PE<o:p></o:p></span></font></p>
</div>
</div>
</div>
</div>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><br>
_______________________________________________<br>
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</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br clear=all>
<br>
-- <br>
Carol Gardner PE<o:p></o:p></span></font></p>
</div>
</div>
</div>
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