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<DIV><SPAN class=937212818-17082006><FONT face=Arial color=#0000ff
size=2>Mike,</FONT></SPAN></DIV>
<DIV><SPAN class=937212818-17082006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=937212818-17082006><FONT face=Arial color=#0000ff size=2>What
great timing you have. I was grappling with this exact issue this morning. You
saved me some time. </FONT></SPAN></DIV>
<DIV><SPAN class=937212818-17082006><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV></DIV>
<DIV><SPAN class=937212818-17082006><FONT face=Arial><FONT size=2><FONT
color=#0000ff>There seems to be a work around for the issue of the min CW temp
at the chiller. <SPAN class=406454720-17082006>You say that "the chiller
has a keyword MIN-COND-T that defualts to 70F and cannot be changed from within
eQuest". </SPAN>I could not find how to change it within the main body of eQUEST
either. However, it seems you CAN change it in a parametric run.<SPAN
class=406454720-17082006> I did this and it seems to be reflected in the chiller
condenser water temp in my hourly
report.</SPAN></FONT></FONT></FONT></SPAN></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Kevin Warren, P.E., CEM, LEED AP<BR>Warren Energy Engineering,
LLC<BR>(610) 255-3798 ph<BR>(610) 255-3406 f</FONT> </DIV>
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<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> BLDG-SIM@GARD.COM
[mailto:BLDG-SIM@GARD.COM]<B>On Behalf Of </B>Mike Tillou<BR><B>Sent:</B>
Thursday, August 17, 2006 1:58 PM<BR><B>To:</B>
BLDG-SIM@GARD.COM<BR><B>Subject:</B> [BLDG-SIM] Condenser Water Reset in
eQuest<BR><BR></FONT></DIV><!-- Converted from text/rtf format --><BR>
<P><FONT face=Arial size=2>Hi all..I thought I would share a couple of tips on
using Condenser Water Reset Strategies in eQuest . Hopefully some of you will
find this useful.</FONT></P>
<P><FONT face=Arial size=2>We just finished modeling a chiller plant where we
looked at using low condenser water temperatures ( below 60F ) as an energy
efficiency measure. The project is in a climate with very low wetbulb
temperatures . There are a couple of quirks I thought I would share
about trying to model a strategy like this. </FONT></P>
<P><FONT face=Arial size=2>The Condenser Loop Control tab has several options
for resetting the loop temperature. If you notice MIN-RESET-T always
defaults to 70F. </FONT></P>
<P><FONT face=Arial size=2>Issue #1: If you reset the Condenser
loop MIN-RESET-T lower than 70F (say 65F) and then run an hourly report to
check the loop temperature everything looks like it's working fine.
BUT..if you also check the chiller entering condenser temperature you will
find it never goes below 70F even though the condenser loop says it should be
lower. This is because the chiller has a keyword MIN-COND-T that
defualts to 70F and cannot be changed from within eQuest. You have to
change the keyword manually in the input file by adding the line, MIN-COND-T =
65 underneath the definition of your chiller.</FONT></P>
<P><FONT face=Arial size=2> </FONT><BR><FONT face=Arial size=2>The most
likely reason this defaults to 70F is because the default chiller performance
curves were not designed for condenser temperatures below 70F ( someone
should correct me if this is wrong) </FONT></P>
<P><FONT face=Arial size=2>If you want to try and model condenser water
temperatures below 70F I highly recommend you create custom performance curves
that include data points that describe the operation of your chiller at the
appropriate condenser water conditions.</FONT></P>
<P><FONT face=Arial size=2>That brings me to Issue #2.</FONT> </P>
<P><FONT face=Arial size=2>The MIN-COND-T keyword has a lower limit of
60F. In other words even if you create the appropriate performance
curves and then try to set MIN-COND-T lower than 60F you will get a
simulation error. </FONT></P>
<P><FONT face=Arial size=2>You can work around this by using the DIAGNOSTIC
keyword "NO-LIMITS". In effect this turns off both the Max and Min
keyword limits. You can then simulate chiller operation with very low
condesner water temperatures. </FONT></P>
<P><FONT face=Arial size=2>If you use the "NO-LIMITS" keyword do so very
carefully. This is a very important error checking function of DOE2.2
eQuest.</FONT></P>
<P><B><FONT face=Arial size=2>Mike </FONT></B></P><BR>
<P><B><FONT face=Arial size=2>Michael Tillou, PE<BR>etc Group, Inc.<BR>PO Box
7, Williamstown, MA 01267<BR>ph. (413) 458-9870 fx. (413)
458-9875<BR></FONT><BR></B></P><BR>
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