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<DIV dir=ltr align=left><FONT face="Lucida Console" size=2><SPAN
class=583332919-21122006>Mark,</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Lucida Console" size=2><SPAN
class=583332919-21122006></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Lucida Console" size=2><SPAN
class=583332919-21122006>I think the basic problem with the curve as
you have defined it is that, for a given flow rate, delta-T is dependent on
firing rate, and thus the value of the leaving water temperature
cannot be assumed and must be calculated. This however can easily done,
using the given firing rate for each entering water temperature
value.</SPAN></FONT></DIV>
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class=583332919-21122006></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Lucida Console" size=2><SPAN
class=583332919-21122006>That being said, the Aerco curve as presented I
think is somewhat ambiguous, and requires a few engineering assumptions to solve
definitively.</SPAN></FONT></DIV>
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class=583332919-21122006></SPAN></FONT><FONT face="Lucida Console" size=2><SPAN
class=583332919-21122006></SPAN></FONT> </DIV>
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class=583332919-21122006></SPAN></FONT><FONT face="Lucida Console" size=2><SPAN
class=583332919-21122006>As I know this is bound to come up very soon in one or
more of the projects I've got sitting in front of me, I spent a little time
today reasoning this out and have published the results in my ongoing ELCCA
Exchange blog:</SPAN></FONT></DIV>
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class=583332919-21122006></SPAN></FONT><FONT face="Lucida Console" size=2><SPAN
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<DIV dir=ltr align=left><FONT face="Lucida Console" size=2><SPAN
class=583332919-21122006><A
href="http://elcca-exchange.blogspot.com/2006/12/equest-boiler-curve-example.html">http://elcca-exchange.blogspot.com/2006/12/equest-boiler-curve-example.html</A></SPAN></FONT></DIV><SPAN
class=583332919-21122006>
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class=583332919-21122006></SPAN></FONT> </DIV>
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class=583332919-21122006></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Lucida Console" size=2>If you wouldn't mind,
please let me know how the curve fit data works... I don't have a
live project just yet with a condensing boiler to test
it on.</FONT></DIV>
<DIV dir=ltr align=left><FONT face="Lucida Console" size=2></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Lucida Console" size=2></FONT> </DIV>
<DIV dir=ltr align=left></SPAN><FONT face="Lucida Console"
size=2>Regards</FONT></DIV>
<DIV dir=ltr align=left><FONT face="Lucida Console" size=2></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Lucida Console" size=2>Brandon Nichols,
PE<BR>Mechanical<BR>HARGIS ENGINEERS<BR>600 Stewart St<BR>Suite 1000<BR>Seattle,
WA 98101<BR>d | 206.436.0400 c | 206.228.8707<BR>o | 206.448.3376 f |
206.448.4450<BR><A
href="http://www.hargis.biz">www.hargis.biz</A><BR></FONT></DIV>
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<FONT face=Tahoma size=2><B>From:</B> BLDG-SIM@GARD.COM
[mailto:BLDG-SIM@GARD.COM] <B>On Behalf Of </B>Mark Nieman<BR><B>Sent:</B>
Thursday, December 21, 2006 9:42 AM<BR><B>To:</B>
BLDG-SIM@GARD.COM<BR><B>Subject:</B> [BLDG-SIM] eQUEST Condensing Boiler
Curve<BR></FONT><BR></DIV>
<DIV></DIV><!-- Converted from text/rtf format -->
<P><FONT face=Courier size=2>Using eQUEST v.3.6, I've taken a stab at creating a
performance curve for an Aerco KC1000 condensing boiler. I've defined
BOILER:HIR-FT = "Aerco-KC1000-HIR-fEWT&LWT" as shown below. This boiler is
being used for a water source heat pump condenser water loop with a CT/HX &
two condensing boilers, piped in a primary loop configuration.</FONT></P>
<P><FONT face=Courier size=2>"Aerco-KC1000-HIR-fEWT&LWT" =
CURVE-FIT </FONT><BR><FONT face=Courier
size=2>
TYPE =
BI-QUADRATIC-T</FONT> <BR><FONT face=Courier size=2>
INPUT-TYPE = DATA</FONT> <BR><FONT
face=Courier size=2> INDEPENDENT-1 = ( 180, 180,
180, 80, 80, 80, 100, 100, 100, 120, 120, </FONT><BR><FONT face=Courier
size=2> 120, 140, 140, 140, 160,
160, 160 )</FONT> <BR><FONT face=Courier size=2>
INDEPENDENT-2 = ( 180, 90, 135, 90, 135, 180, 90, 135, 180,
90, 135, </FONT><BR><FONT face=Courier
size=2> 180, 90, 135, 180, 90,
135, 180 )</FONT> <BR><FONT face=Courier size=2>
DEPENDENT = ( 1, 1.023, 1.019, 1.151,
1.077, 1.065, 1.102, 1.047, </FONT><BR><FONT face=Courier
size=2> 1.038, 1.053, 1.026,
1.017, 1.033, 1.017, 1.012, 1.023, 1.017, </FONT><BR><FONT face=Courier
size=2> 1.007 )</FONT> <BR><FONT
face=Courier size=2> ..</FONT> </P>
<P><FONT face=Courier size=2>Question: Is this a proper curve for this
equipment? Any comments and critiques would be much appreciated. Part of my
difficulty is that HIR-FT is a Bi-Quadratic-T or Bi-Linear-T curve that needs
two temperatures (EWT & LWT) to define the HIR ratio modifier. When looking
at the curves, it's stated as thermal efficiency vs. EWT (return water
temperature) on several different curves based on fire rate of the boiler.
Basically, I assumed a LWT based on firing rate (90F=25%, 135F=75% &
180F=100%). I'm not sure if this is reasonable or not. Per the manual, the
DEPENDENT variable is the ratio of the actual efficiency (based on the curves) /
rated efficiency (at full fire, full load). INDEPENDENT-1 = EWT, INDEPENDENT-2 =
LWT.</FONT></P>
<P><FONT face=Courier size=2>The link to the data sheet is here:</FONT> <BR><A
href="http://www.aerco.com/cgi-bin/docsserv.cgi?idDocument=344"><U><FONT
face=Arial color=#0000ff
size=2>http://www.aerco.com/cgi-bin/docsserv.cgi?idDocument=344</FONT></U></A>
</P>
<P><FONT face=Arial size=2>Mark Nieman, PE, CEM</FONT> <BR><FONT face=Arial
size=2>Sr. Energy Engineer</FONT> <BR><FONT face=Arial size=2>McKinstry
Essention</FONT> <BR><FONT face=Arial size=1>Direct: (206) 832-8152</FONT>
<BR><FONT face=Arial size=1>Cell: (206) 510-4760</FONT> <BR><FONT face=Arial
size=1>FAX: (206) 832-8552</FONT> <BR><A
href="http://www.mckinstry.com"><U><FONT face=Arial color=#0000ff
size=1>http://www.mckinstry.com</FONT></U></A> <BR><I><FONT face=Arial
size=1>"For The Life Of Your Building"</FONT></I> </P><PRE>==================
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