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<br><br><div class="gmail_quote">On Wed, Nov 3, 2010 at 9:48 AM, John T. Forester <span dir="ltr"><<a href="mailto:JohnTF@bvhis.com">JohnTF@bvhis.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
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<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">Nick,</span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; 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></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<ol style="margin-top: 0in;" start="1" type="1">
<li class="MsoNormal" style="color: navy;"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; 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></li>
<li class="MsoNormal" style="color: navy;"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; 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></li>
<li class="MsoNormal" style="color: navy;"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; 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></li>
<li class="MsoNormal" style="color: navy;"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; 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></li>
</ol><div class="im">
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">John</span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<div>
<p class="MsoNormal"><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">John T.
Forester</span></font><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">, P.E., LEED AP,
Mechanical Design Engineer </span></font><b><b><font color="#0000a0" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: rgb(0, 0, 160);">I BVH Integrated Services I</span></font></b></b><b><b><font color="black" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: black;"> </span></font></b></b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">617.658.9008 tel </span></font><b><b><font color="#0000a0" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: rgb(0, 0, 160);">I</span></font></b></b><b><b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;"> </span></font></b></b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">617.244.3753 fax</span></font><font color="#0000a0" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: rgb(0, 0, 160);"> <b><b><font face="Arial"><span style="font-family: Arial;">I</span></font></b></b></span></font><b><b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;"> </span></font></b></b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">One
Gateway Center Suite 506, Newton
MA 02458 </span></font><b><b><font color="#0000a0" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: rgb(0, 0, 160);">I <a href="http://www.bvhis.com" target="_blank">www.bvhis.com</a> I Hartford ● New Haven ●
Boston</span></font></b></b><font color="gray"><span style="color: gray;"></span></font></p>
</div>
</div><div>
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<p class="MsoNormal"><b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma; font-weight: bold;">From:</span></font></b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma;"> Nick Caton
[mailto:<a href="mailto:ncaton@smithboucher.com" target="_blank">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> John
T. Forester; <a href="mailto:equest-users@lists.onebuilding.org" target="_blank">equest-users@lists.onebuilding.org</a><div><div></div><div class="h5"><br>
<b><span style="font-weight: bold;">Subject:</span></b> RE: [Equest-users]
Chiller Curves (oh boy!)</div></div></span></font></p>
</div><div><div></div><div class="h5">
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">John,</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">I’d like to
apply/paraphrase your advice to a few conditions to be sure I’m getting it
correctly: </span></font></p>
<p><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"><span>-<font face="Times New Roman" size="1"><span style="font: 7pt "Times New Roman";">
</span></font></span></span></font><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"><span>-<font face="Times New Roman" size="1"><span style="font: 7pt "Times New Roman";">
</span></font></span></span></font><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"><span>-<font face="Times New Roman" size="1"><span style="font: 7pt "Times New Roman";">
</span></font></span></span></font><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><u><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">Profound (to me)
Conclusion</span></font></u><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">: 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></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">Does this all sound
right?</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">~Nick</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">James, </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">~Nick</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<div>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"><img src="" alt="cid:489575314@22072009-0ABB" border="0" height="37" width="119"></span></font><b><font color="#2d4d5e" face="Stylus BT" size="2"><span style="font-size: 11pt; font-family: "Stylus BT"; color: rgb(45, 77, 94); font-weight: bold;"></span></font></b></p>
<p class="MsoNormal"><b><font color="#2d4d5e" face="Stylus BT" size="2"><span style="font-size: 11pt; font-family: "Stylus BT"; color: rgb(45, 77, 94); font-weight: bold;"> </span></font></b></p>
<p class="MsoNormal"><b><font color="#2d4d5e" face="Stylus BT" size="2"><span style="font-size: 11pt; font-family: "Stylus BT"; color: rgb(45, 77, 94); font-weight: bold;">NICK
CATON, E.I.T.</span></font></b><b><font color="#2d4d5e" face="Stylus BT"><span style="font-family: "Stylus BT"; color: rgb(45, 77, 94); font-weight: bold;"></span></font></b></p>
<p class="MsoNormal"><font color="#cc9900" face="Calibri" size="1"><span style="font-size: 7.5pt; font-family: Calibri; color: rgb(204, 153, 0);">PROJECT ENGINEER</span></font><font color="#cc9900" size="1"><span style="font-size: 7.5pt; color: rgb(204, 153, 0);"></span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);">25501 west valley
parkway</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);">olathe</span></font><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);"> ks 66061</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);">direct 913 344.0036</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);">fax 913 345.0617</span></font></p>
<p class="MsoNormal"><i><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94); font-style: italic;">Check
out our new web-site @ </span></font></i><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"><a href="http://www.smithboucher.com" title="blocked::www.smithboucher.com" target="_blank"><font size="2"><span style="font-size: 10pt;">www.smithboucher.com</span></font></a></span></font><u><font color="blue" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: blue;"> </span></font></u><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"></span></font></p>
</div>
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<p class="MsoNormal"><b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma; font-weight: bold;">From:</span></font></b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma;"> John T. Forester [mailto:<a href="mailto:JohnTF@BVHis.com" target="_blank">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">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></p>
</div>
</div>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">Nick,</span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; 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></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; 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></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; 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></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">Hope this helps,</span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;">John</span></font></p>
<p class="MsoNormal"><font color="navy" face="Arial" size="2"><span style="font-size: 10pt; font-family: Arial; color: navy;"> </span></font></p>
<div>
<p class="MsoNormal"><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">John T.
Forester</span></font><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">, P.E., LEED AP,
Mechanical Design Engineer </span></font><b><b><font color="#0000a0" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: rgb(0, 0, 160);">I BVH Integrated Services I</span></font></b></b><b><b><font color="black" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: black;"> </span></font></b></b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">617.658.9008 tel </span></font><b><b><font color="#0000a0" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: rgb(0, 0, 160);">I</span></font></b></b><b><b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;"> </span></font></b></b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">617.244.3753 fax</span></font><font color="#0000a0" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: rgb(0, 0, 160);"> <b><b><font face="Arial"><span style="font-family: Arial;">I</span></font></b></b></span></font><b><b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;"> </span></font></b></b><font color="gray" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: gray;">One Gateway Center Suite
506, Newton MA 02458 </span></font><b><b><font color="#0000a0" face="Arial" size="1"><span style="font-size: 8.5pt; font-family: Arial; color: rgb(0, 0, 160);">I <a href="http://www.bvhis.com" target="_blank">www.bvhis.com</a> I Hartford ● New Haven
● Boston</span></font></b></b><font color="gray"><span style="color: gray;"></span></font></p>
</div>
<div>
<p class="MsoNormal" style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"><hr size=2
width="100%" align=center tabindex=-1> </span></font></p>
<p class="MsoNormal"><b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma; font-weight: bold;">From:</span></font></b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma;">
<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><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">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></p>
</div>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">Thanks for the
response Carol!</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">That 120% load case
is what I’m getting at – let me try to explain a little further:</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">I’m asking – are
both approaches right? </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);">~Nick.</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"><img src="" alt="cid:489575314@22072009-0ABB" border="0" height="37" width="119"></span></font><b><font color="#2d4d5e" face="Stylus BT" size="2"><span style="font-size: 11pt; font-family: "Stylus BT"; color: rgb(45, 77, 94); font-weight: bold;"></span></font></b></p>
<p class="MsoNormal"><b><font color="#2d4d5e" face="Stylus BT" size="2"><span style="font-size: 11pt; font-family: "Stylus BT"; color: rgb(45, 77, 94); font-weight: bold;"> </span></font></b></p>
<p class="MsoNormal"><b><font color="#2d4d5e" face="Stylus BT" size="2"><span style="font-size: 11pt; font-family: "Stylus BT"; color: rgb(45, 77, 94); font-weight: bold;">NICK
CATON, E.I.T.</span></font></b><b><font color="#2d4d5e" face="Stylus BT"><span style="font-family: "Stylus BT"; color: rgb(45, 77, 94); font-weight: bold;"></span></font></b></p>
<p class="MsoNormal"><font color="#cc9900" face="Calibri" size="1"><span style="font-size: 7.5pt; font-family: Calibri; color: rgb(204, 153, 0);">PROJECT ENGINEER</span></font><font color="#cc9900" size="1"><span style="font-size: 7.5pt; color: rgb(204, 153, 0);"></span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);">25501 west valley
parkway</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);">olathe</span></font><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);"> ks 66061</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);">direct 913 344.0036</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94);">fax 913 345.0617</span></font></p>
<p class="MsoNormal"><i><font color="#2d4d5e" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: rgb(45, 77, 94); font-style: italic;">Check
out our new web-site @ </span></font></i><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"><a href="http://www.smithboucher.com" title="blocked::www.smithboucher.com" target="_blank"><font size="2"><span style="font-size: 10pt;">www.smithboucher.com</span></font></a></span></font><u><font color="blue" face="Calibri" size="2"><span style="font-size: 10pt; font-family: Calibri; color: blue;"> </span></font></u><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"></span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Calibri" size="2"><span style="font-size: 11pt; font-family: Calibri; color: rgb(31, 73, 125);"> </span></font></p>
<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><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma; font-weight: bold;">From:</span></font></b><font face="Tahoma" size="2"><span style="font-size: 10pt; font-family: Tahoma;"> Carol Gardner [mailto:<a href="mailto:cmg750@gmail.com" target="_blank">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">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></p>
</div>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p class="MsoNormal" style="margin-bottom: 12pt;"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">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:</span></font></p>
<div style="border-width: 1pt medium; border-style: solid none; border-color: rgb(153, 153, 153) -moz-use-text-color; padding: 0in;">
<div>
<div>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
</div>
</div>
</div>
<div>
<div>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"><a href="http://volume2dictionary.htm" target="_blank">Volume 2: Dictionary</a><span> > </span><a href="http://hvaccomponents.htm" target="_blank">HVAC
Components</a><span> > </span><a href="http://curvefit.htm" target="_blank"><font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">CURVE</span></font>-<font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">FIT</span></font></a><span> > </span><a href="http://inputtypedata.htm" target="_blank">INPUT-TYPE
= DATA</a></span></font></p>
</div>
<h5><b><font face="Times New Roman" size="2"><span style="font-size: 10pt;">INDEPENDENT-2</span></font></b></h5>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;">Used for all <font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">curves</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.</span></font></p>
<p><b><font face="Arial" size="3"><span style="font-size: 12pt; font-family: Arial; font-weight: bold;">Example 1</span></font></b>: defining a <font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">curve</span></font> by
inputting a set of data points.</p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;">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.</span></font></p>
<p><a name="12c12a536c514b6a__Ref490744859"></a><a name="12c12a536c514b6a__Ref490744804"></a><font face="Times New Roman" size="3"><span style="font-size: 12pt;">Table 46
Cooling capacity (kBtu/hr) vs. temperature</span></font></p>
<div style="margin-top: 2pt; margin-bottom: 2pt;">
<div align="center">
<table style="border-collapse: collapse;" border="0" cellpadding="0" cellspacing="0">
<tbody><tr>
<td rowspan="2" style="width: 1in; border: 1pt solid windowtext; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt;" bgcolor="aqua" valign="top" width="96">
<p style="margin-top: 0in; text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">Outside<br>
Dry-bulb</span></font></b></p>
</td>
<td colspan="3" style="width: 3in; border-width: 1pt 1pt medium medium; border-style: solid solid none none; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt; border-color: -moz-use-text-color;" bgcolor="aqua" valign="top" width="288">
<p style="text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">Entering
Wet-bulb</span></font></b></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium medium 1pt; border-style: none none solid; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt; border-color: -moz-use-text-color -moz-use-text-color windowtext;" bgcolor="aqua" valign="top" width="96">
<p style="text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">72F</span></font></b></p>
</td>
<td style="width: 1in; border-width: medium medium 1pt; border-style: none none solid; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt; border-color: -moz-use-text-color -moz-use-text-color windowtext;" bgcolor="aqua" valign="top" width="96">
<p style="text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">67F</span></font></b></p>
</td>
<td style="width: 1in; border-width: medium 1pt 1pt medium; border-style: none solid solid none; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color;" bgcolor="aqua" valign="top" width="96">
<p style="text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">62F</span></font></b></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium 1pt; border-style: none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">85F</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">69</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">65</span></font></p>
</td>
<td style="width: 1in; border-width: medium 1pt medium medium; border-style: none solid none none; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext -moz-use-text-color -moz-use-text-color;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">60</span></font></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium 1pt; border-style: none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">95F</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">68</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">63 (ARI)</span></font></p>
</td>
<td style="width: 1in; border-width: medium 1pt medium medium; border-style: none solid none none; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext -moz-use-text-color -moz-use-text-color;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">57</span></font></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium 1pt; border-style: none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">105F</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">65</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">60</span></font></p>
</td>
<td style="width: 1in; border-width: medium 1pt medium medium; border-style: none solid none none; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext -moz-use-text-color -moz-use-text-color;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">53</span></font></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium 1pt 1pt; border-style: none solid solid; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">115F</span></font></p>
</td>
<td style="width: 1in; border-width: medium medium 1pt; border-style: none none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">62</span></font></p>
</td>
<td style="width: 1in; border-width: medium medium 1pt; border-style: none none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">55</span></font></p>
</td>
<td style="width: 1in; border-width: medium 1pt 1pt medium; border-style: none solid solid none; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color;" valign="top" width="96">
<p style="margin-bottom: 0.0001pt; text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">49</span></font></p>
</td>
</tr>
</tbody></table>
</div>
</div>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;">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="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">curve</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</span></font></p>
<p><a name="12c12a536c514b6a__Ref490745029"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">Table </span></font></a>47 Normalized capacity
vs. temperature</p>
<div style="margin-top: 2pt; margin-bottom: 2pt;">
<div align="center">
<table style="border-collapse: collapse;" border="0" cellpadding="0" cellspacing="0">
<tbody><tr>
<td rowspan="2" style="width: 1in; border: 1pt solid windowtext; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt;" bgcolor="aqua" valign="top" width="96">
<p style="margin-top: 0in; text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">Outside<br>
Dry-bulb</span></font></b></p>
</td>
<td colspan="3" style="width: 3in; border-width: 1pt 1pt medium medium; border-style: solid solid none none; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt; border-color: -moz-use-text-color;" bgcolor="aqua" valign="top" width="288">
<p style="text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">Entering
Wet-bulb</span></font></b></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium medium 1pt; border-style: none none solid; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt; border-color: -moz-use-text-color -moz-use-text-color windowtext;" bgcolor="aqua" valign="top" width="96">
<p style="text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">72F</span></font></b></p>
</td>
<td style="width: 1in; border-width: medium medium 1pt; border-style: none none solid; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt; border-color: -moz-use-text-color -moz-use-text-color windowtext;" bgcolor="aqua" valign="top" width="96">
<p style="text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">67F</span></font></b></p>
</td>
<td style="width: 1in; border-width: medium 1pt 1pt medium; border-style: none solid solid none; background: none repeat scroll 0% 0% aqua; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color;" bgcolor="aqua" valign="top" width="96">
<p style="text-align: center;" align="center"><b><font face="Times New Roman" size="3"><span style="font-size: 12pt; font-weight: bold;">62F</span></font></b></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium 1pt; border-style: none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">85F</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">1.095</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">1.032</span></font></p>
</td>
<td style="width: 1in; border-width: medium 1pt medium medium; border-style: none solid none none; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext -moz-use-text-color -moz-use-text-color;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">0.952</span></font></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium 1pt; border-style: none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">95F</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">1.079</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">1.0 (ARI)</span></font></p>
</td>
<td style="width: 1in; border-width: medium 1pt medium medium; border-style: none solid none none; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext -moz-use-text-color -moz-use-text-color;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">0.905</span></font></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium 1pt; border-style: none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">105F</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">1.032</span></font></p>
</td>
<td style="width: 1in; padding: 0in 5.4pt;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">0.952</span></font></p>
</td>
<td style="width: 1in; border-width: medium 1pt medium medium; border-style: none solid none none; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext -moz-use-text-color -moz-use-text-color;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">0.841</span></font></p>
</td>
</tr>
<tr>
<td style="width: 1in; border-width: medium 1pt 1pt; border-style: none solid solid; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">115F</span></font></p>
</td>
<td style="width: 1in; border-width: medium medium 1pt; border-style: none none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">0.984</span></font></p>
</td>
<td style="width: 1in; border-width: medium medium 1pt; border-style: none none solid; padding: 0in 5.4pt; border-color: -moz-use-text-color -moz-use-text-color windowtext;" valign="top" width="96">
<p style="text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">0.873</span></font></p>
</td>
<td style="width: 1in; border-width: medium 1pt 1pt medium; border-style: none solid solid none; padding: 0in 5.4pt; border-color: -moz-use-text-color windowtext windowtext -moz-use-text-color;" valign="top" width="96">
<p style="margin-bottom: 0.0001pt; text-align: center;" align="center"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">0.778</span></font></p>
</td>
</tr>
</tbody></table>
</div>
</div>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;">The <font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">CURVE</span></font>-<font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">FIT</span></font> input will look like
the following:</span></font></p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;">CAP-<font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">CURVE</span></font>-1
= <font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">CURVE</span></font>-<font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">FIT</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) ..</span></font></p>
<p><b><font face="Arial" size="3"><span style="font-size: 12pt; font-family: Arial; font-weight: bold;">Example 2:</span></font></b> Defining a <font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">curve</span></font> by
inputting coefficients</p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;">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="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">curve</span></font>
that will give a constant efficiency. The <font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">curve</span></font> TYPE is QUADRATIC in
the part load ratio (PLR). PLR correction <font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">curves</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="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">curve</span></font> we want is: 0.0 + 1.0*PLR +
0.0*PLR*PLR. The input will look like:</span></font></p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;">New-Furnace-HIR-fPLR = <font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">CURVE</span></font>-<font color="white"><span style="color: white; background: none repeat scroll 0% 0% rgb(49, 106, 197);">FIT</span></font><br>
TYPE
= QUADRATIC<br>
INPUT-TYPE = COEFFICIENTS<br>
COEFFICIENTS = (0.0,1.0,0.0) ..</span></font></p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;">Then in the SYSTEM command we include:</span></font></p>
<p><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> FURNACE-HIR-FPLR = New-Furnace-HIR-fPLR</span></font></p>
</div>
<p class="MsoNormal" style="margin-bottom: 12pt;"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
<div>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">On Tue, Nov 2, 2010 at 3:21 PM, Nick Caton <<a href="mailto:ncaton@smithboucher.com" target="_blank">ncaton@smithboucher.com</a>> wrote:</span></font></p>
<div>
<div>
<p class="MsoNormal"><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);">Hi everyone!</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);"> </span></font></p>
<p><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);">1.</span></font><font color="#1f497d" size="1"><span style="font-size: 7pt; color: rgb(31, 73, 125);"> </span></font><font color="#1f497d"><span style="color: rgb(31, 73, 125);">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></p>
<p><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);">2.</span></font><font color="#1f497d" size="1"><span style="font-size: 7pt; color: rgb(31, 73, 125);"> </span></font><font color="#1f497d"><span style="color: rgb(31, 73, 125);">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></p>
<p><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);">3.</span></font><font color="#1f497d" size="1"><span style="font-size: 7pt; color: rgb(31, 73, 125);"> </span></font><font color="#1f497d"><span style="color: rgb(31, 73, 125);">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></p>
<p class="MsoNormal"><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);"> </span></font></p>
<p class="MsoNormal" style="margin-left: 0.25in;"><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);"> ~Nick</span></font></p>
<p class="MsoNormal"><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);"> </span></font></p>
<div>
<p class="MsoNormal"><font color="#1f497d" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(31, 73, 125);"><img src="" alt="cid:489575314@22072009-0ABB" border="0" height="37" width="119"></span></font></p>
<p class="MsoNormal"><b><font color="#2d4d5e" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(45, 77, 94); font-weight: bold;"> </span></font></b></p>
<p class="MsoNormal"><b><font color="#2d4d5e" face="Times New Roman" size="3"><span style="font-size: 12pt; color: rgb(45, 77, 94); font-weight: bold;">NICK CATON, E.I.T.</span></font></b></p>
<p class="MsoNormal"><font color="#cc9900" face="Times New Roman" size="1"><span style="font-size: 7.5pt; color: rgb(204, 153, 0);">PROJECT ENGINEER</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Times New Roman" size="2"><span style="font-size: 10pt; color: rgb(45, 77, 94);">25501 west valley parkway</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Times New Roman" size="2"><span style="font-size: 10pt; color: rgb(45, 77, 94);">olathe</span></font><font color="#2d4d5e" size="2"><span style="font-size: 10pt; color: rgb(45, 77, 94);"> ks 66061</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Times New Roman" size="2"><span style="font-size: 10pt; color: rgb(45, 77, 94);">direct 913 344.0036</span></font></p>
<p class="MsoNormal"><font color="#2d4d5e" face="Times New Roman" size="2"><span style="font-size: 10pt; color: rgb(45, 77, 94);">fax 913 345.0617</span></font></p>
<p class="MsoNormal"><i><font color="#2d4d5e" face="Times New Roman" size="2"><span style="font-size: 10pt; color: rgb(45, 77, 94); font-style: italic;">Check out our new web-site @ </span></font></i><font color="#1f497d"><span style="color: rgb(31, 73, 125);"><a href="http://www.smithboucher.com" title="blocked::www.smithboucher.com" target="_blank"><font size="2"><span style="font-size: 10pt;">www.smithboucher.com</span></font></a></span></font><u><font color="blue" size="2"><span style="font-size: 10pt; color: blue;"> </span></font></u></p>
</div>
<p class="MsoNormal"><b><font face="Times New Roman" size="2"><span style="font-size: 10pt; font-weight: bold;">EIR-FPLR</span></font></b></p>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">Takes the U-name
of a curve that adjusts the electric input ratio as a function of</span></font></p>
<p class="MsoNormal" style="margin-left: 0.5in;"><font face="Symbol" size="3"><span style="font-size: 12pt; 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></p>
<p class="MsoNormal" style="margin-left: 0.5in;"><font face="Symbol" size="3"><span style="font-size: 12pt; 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. </p>
<p class="MsoNormal" style="margin-left: 2.7pt;"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">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.</span></font></p>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;">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></span></font></p>
<p class="MsoNormal"><b><font color="red" face="Times New Roman" size="3"><span style="font-size: 12pt; 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.</p>
<p style="margin-bottom: 12pt;"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"> </span></font></p>
</div>
</div>
<p class="MsoNormal" style="margin-bottom: 12pt;"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"><br>
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</div>
<p class="MsoNormal"><font face="Times New Roman" size="3"><span style="font-size: 12pt;"><br>
<br clear="all">
<br>
-- <br>
Carol Gardner PE</span></font></p>
</div></div></div>
</div>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Carol Gardner PE<br>
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