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<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff size=2>John,
I think the answer to your question has two parts:</FONT></SPAN></DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff size=2>1. DOE
uses two curves for modifying the full load EIR (1/COP) of a
<U>constant</U> speed chiller. The first adjusts for part load and the
second for temperature. </FONT></SPAN></DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2>I use a curve with <U>fixed</U> CHWT and CWT at various part
load conditions (at <U>design</U> conditions not ARI rated
conditions) for the EIR f(PLR) curve (the one you're asking about) and
create a second curve based on various combinations of CHWT, CWT at full
load for the EIR f(LCHWT, ECWT) curve. The assumption, I think, is
that the PLR curve reamins relatively uniform as the water temperatures change
so once you have the shape of the PLR curve you can account for
temperature differences with a second curve.</FONT></SPAN></DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff size=2>2. The
above methodology works fine for constant speed chillers but needs to be
modified for variable speed chillers. Rather than using EIR F(PLR) you
need to use EIR f(PLR,dT). This curve now accounts for the change
in the difference of the water temperature across the chiller. See
Volume 6 of the DOE 2.2 v41 reference manual available at <A
href="http://www.DOE2.com">www.DOE2.com</A>, there is a section on chiller
performance that explains this much better than I could do. DOE
2.2 v41 incorporates this change and has default curves for
both.</FONT></SPAN></DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff size=2>It
sounds like you both may be correct depending on the type of chiller you want to
model.</FONT></SPAN></DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff size=2>Mike
Tillou, PE</FONT></SPAN></DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff size=2>etc
Group, Inc</FONT></SPAN></DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2>413-664-9070</FONT></SPAN></DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=976153420-15102003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV></DIV>
<DIV><FONT face=Tahoma size=2>-----Original Message-----<BR><B>From:</B>
postman@gard.com [mailto:postman@gard.com] <B>On Behalf Of </B>Aulbach,
John<BR><B>Sent:</B> Wednesday, October 15, 2003 2:23 PM<BR><B>To:</B>
BLDG-SIM@GARD.COM<BR><B>Subject:</B> [BLDG-SIM] Major disagreement on Chiller
Performance Curves in DOE-2.1E and DOE-2.2<BR><BR></DIV></FONT>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<P><FONT size=2>I am having a "friendly" disagreement with a colleague on what
chiller curves to ask for from a manufacturer to input into DOE-2 (could be
either 2.1E or 2.2). We both agree that the infamous ARI point for a 100% load
should be input. But the curves are where we disagree.</FONT></P>
<P><FONT size=2>Is the Default DOE-2 curve for % Power versus % Tons the ARI
curve with the allowable reduction in condenser water temperature, or is it
based on the FIXED 85°F entering condenser water and FIXED 44°F leaving
chilled water ALL the way down the curve?</FONT></P>
<P><FONT size=2>Therefore, when I am given a chiller with a variable speed
drive installed, what parameters should I ask for in such a Power/Tons to be
FIXED ???</FONT></P><BR><BR><BR><BR>
<P><FONT size=2>John R. Aulbach, PE, CEM</FONT> <BR><FONT size=2>Project
Engineer</FONT> <BR><FONT size=2>Sempra Energy Solutions</FONT> <BR><FONT
size=2>555 West Fifth Street</FONT> <BR><FONT size=2>Mail Location 27F3</FONT>
<BR><FONT size=2>Los Angeles, CA 90013</FONT> <BR><FONT size=2>Tel: (213)
244-8551 Cell (213) 219-4875</FONT> <BR><FONT size=2> </FONT> </P>
<P><FONT size=2>"Sempra Energy Solutions is not the same company as SDG&E/
SoCalGas, the Utilities. Sempra Energy Solutions is not regulated by the
California Public Utilities Commission, and you do not have to buy Sempra
Energy Solutions products or services to continue to receive quality regulated
service from the Utilities." </FONT></P><PRE>
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