<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE>Defining a chiller size and E-I-R in DOE-2.1E</TITLE>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 5.50.4522.1800" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial size=2>John,</FONT></DIV>
<DIV><FONT face=Arial size=2>As far as I know, the nominal capacity and EIR
numbers are as you say - 100% load, 44/85. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The default curves for modifying the capacity and
EIR as functions of CHW and CW temperature will return a value of 1.00 at 44 and
85. What DOE does is use the hourly values for CHW and CW temp and then
multiplies the nominal EIR and capacity by the results of the other
formulae. For example, if you are modeling CW reset, and your CW temp goes
down in the spring or fall, then the vaule of the EIR f(CHW, CW) formula will
return less than 1 in these conditions, and the value of capacity f (CHW, CW)
will be greater than 1. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If you are modeling a system where CHW temp is
always 44 and CW temp is always 85, then you don't need to mess around with the
formulae that are based on CHW and CW temp. However, I would use actual
mfgr data for the chiller performance as a function of PLR, especially if you
are modeling a rotary screw chiller or a chiller with a VFD.
</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If you are modeling CHW and CW temps other than
44/85, I would also get mfgr data on the chiller performance at other points and
use the data to create new coefficients for the curves. I recently did a
job where we were modeling a rotary chiller as the base case and a VFD-driven
centrifugal with CW reset and 48 F CHW along with free cooling in the winter as
the proposed case. So I created and debugged all kinds of curves and
coefficients for that job. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If you would like any more info on creating new
curves, I can give you some tips on that - let me know.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I would also be interested in hearing what others
in the group have to say on this topic - if you can forward me any other
responses you have gotten, I would appreciate it.</FONT></DIV>
<DIV><FONT face=Arial size=2><BR>Sincerely,</DIV>
<DIV> </DIV>
<DIV>Alec Stevens<BR>DMI<BR>p: 617-527-1525x105<BR>f: 617-527-6606<BR>e: <A
href="mailto:astevens@dmiinc.com">astevens@dmiinc.com</A><BR></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV> ----- Original Message ----- </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=JAulbach@semprasolutions.com
href="mailto:JAulbach@semprasolutions.com">Aulbach, John</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=BLDG-SIM@gard.com
href="mailto:BLDG-SIM@gard.com">BLDG-SIM@gard.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, June 15, 2001 5:02 PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [BLDG-SIM] Defining a chiller
size and E-I-R in DOE-2.1E</DIV>
<DIV><BR></DIV>
<P><FONT face=Arial size=2>I don't currently have a DOE-2 Engineering
Document, so this question is posed to the DOE "gods and gurus":</FONT> </P>
<P><FONT face=Arial size=2>There are three curves that modify the
(capacity)/(part load ratio)/(electric input ratio) in DOE-2 (or PowerDOE or
eQuest) of a chiller (let's use a hermetic centrifugal chiller for this
example). Within PLANT, there is a place to insert a "nominal capacity"
and an "electric input ratio".</FONT></P>
<P><FONT face=Arial size=2>The question is, whatever I put into these input
slots represent what? ARI conditions? 100% design?</FONT> </P>
<P><FONT face=Arial size=2>And then the three curves modify these vs. load,
entering condenser water, and exiting chilled water. So the 100% point is what
(full load, 44 DegF CHW leaving, and 85 DegF Condens.water
entering?</FONT></P>
<P><B><FONT face=Arial size=2>John R. Aulbach, PE, CEM</FONT></B> <BR><FONT
face=Arial size=2>Project Engineer</FONT> <BR><FONT face=Arial size=2>Sempra
Energy Solutions</FONT> <BR><FONT face=Arial size=2>555 West Fifth
Street</FONT> <BR><FONT face=Arial size=2>Mail Location 27F3</FONT> <BR><FONT
face=Arial size=2>Los Angeles, CA 90071</FONT> <BR><FONT face=Arial size=2>Tel
:(213) 244-8551 Beeper (888) 520-1051</FONT> </P>
<P><FONT face="Times New Roman" 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><BR><BR><PRE>
==================
You received this e-mail because you are subscribed
to the BLDG-SIM@GARD.COM mailing list. To unsubscribe
from this mailing list send a blank message to
BLDG-SIM-UNSUBSCRIBE@GARD.COM
</PRE></BLOCKQUOTE><PRE>
===========================
You received this e-mail because you are subscribed
to the BLDG-SIM@GARD.COM mailing list. To unsubscribe
from this mailing list send a blank message to
BLDG-SIM-UNSUBSCRIBE@GARD.COM
</PRE></BODY></HTML>