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<DIV dir=ltr align=left><SPAN class=188050009-13082007><FONT face=Arial
color=#0000ff size=2>Brandon,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=188050009-13082007><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=188050009-13082007><FONT face=Arial
color=#0000ff size=2>We just implemented, in ESP-r, an upgraded boiler
model that accepts a series of coefficients to represent a complex curve fit
involving both return water temperature and firing rate, which are the key
parameters determining condensing boiler efficiency. The coefficents for
the model equation are generated using an Excel spreadsheet calculator, with
data input exactly like what is in the graph in your ELCCA post. In
our modelling scheme we allow for outdoor air compensation acting directly on
the boiler flow temperature setpoint (aquastat setting) both for on-off and
modulating versions of the boiler model. Other than that, it is just
our two node boiler model for the dynamic part. More info on this is
contained in a project report at <A
href="http://www.sesg.strath.ac.uk/Downloads/Report_BRE_E302_040707.pdf">http://www.sesg.strath.ac.uk/Downloads/Report_BRE_E302_040707.pdf</A> (look
at P6).</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=188050009-13082007><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=188050009-13082007><FONT face=Arial
color=#0000ff size=2>Hope this is of interest.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=188050009-13082007>
<DIV class=Section1>
<DIV>
<DIV>
<DIV>
<DIV>
<P class=MsoAutoSig><SPAN style="FONT-FAMILY: Helvetica">Jeremy
Cockroft<BR><BR><B style="mso-bidi-font-weight: normal"><SPAN
style="COLOR: green">E<SPAN class=188050009-13082007>nergy </SPAN>S<SPAN
class=188050009-13082007>ystems </SPAN>R<SPAN class=188050009-13082007>esearch
</SPAN>U<SPAN class=188050009-13082007>nit</SPAN><BR></SPAN></B>University of
Strathclyde<BR>75 Montrose Street<BR>Glasgow G1 1XJ<BR>phone<SPAN
style="mso-spacerun: yes"> </SPAN>+44(0)141 548
5765<BR>fax<SPAN style="mso-spacerun: yes">
</SPAN><SPAN style="mso-spacerun: yes"> </SPAN>+44(0)141 552
5105<BR></SPAN><SPAN style="FONT-FAMILY: Helvetica">email<SPAN
style="mso-spacerun: yes"> </SPAN><A
href="mailto:jeremy@esru.strath.ac.uk">jeremy@esru.strath.ac.uk</A><BR>website<SPAN
style="mso-spacerun: yes"> </SPAN><A
href="http://www.esru.strath.ac.uk/">www.esru.strath.ac.uk</A></SPAN><SPAN
lang=EN-US style="mso-ansi-language: EN-US"><o:p></o:p></SPAN></P>
<P class=MsoAutoSig></SPAN>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B> BLDG-SIM@gard.com
[mailto:BLDG-SIM@gard.com] <B>On Behalf Of </B>Brandon Nichols<BR><B>Sent:</B>
10 August 2007 20:12<BR><B>To:</B> BLDG-SIM@gard.com<BR><B>Subject:</B>
[BLDG-SIM] Condensing Boiler Curve
HIR<BR></FONT><BR></P></DIV></DIV></DIV></DIV></DIV></DIV>
<DIV></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>All,</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>Some time ago I began developing <A
href="http://elcca-exchange.blogspot.com/2006/12/equest-boiler-curve-example.html">this
post</A> describing the derivation of a condensing boiler HIR performance curve
based on boiler supply and return water temperature.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>By popular request and the requirements of a current
project, I now have the incentive to actually try implementing it.
</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>This has turned out to be not as simple as I would've
expected, when using the HIR-FT performance curve in the parametric run,
there is no change from the baseline case with a constant 1.25 HIR. A
couple of things I noticed that might be contributing to the
problem:</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>• While the built-in performance curve HIR-FT
function implies on the eQuest dialog box that it is a function of boiler EWT
and LWT, the DOCUMENTATION states that the lesser parameter is supplied by
either the zone temperature or the outdoor temperature, depending on the
value of the LOCATION keyword. Is HIR-FT a function of boiler return water
temperature (i.e. EWT) or not?</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>• It is impossible to set via the dialog box the
HIR-FPLR to 'undefined' in the baseline case; when 'undefined' is selected,
'Atmospheric-Blr-HIR-fPLR' jumps back as the default on leaving the
dialogue. Could this performance curve be overriding the the HIR-FT
performance curve?</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>• While it should be trivial for someone more familiar
with BDL to simply define a keyword expression (or input macro or
function... hmm, which one?) to compute the HIR based on EWT and LWT,
however I do not know which approach to take (expression, macro, or function)
and could not find a reference in the DOE2.2 documentation for accessing
dynamically changing parameters, specifically either the boiler or circulation
loop supply and return temperatures.</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>• Lastly, I have specified the loop supply temperature
to vary based on an OSA reset schedule, but in the case of the condensing
boiler I would also like the boiler aquastat setpoint to be reset (this
presumably will reset the temperature of the boiler LWT). A similar
problem to the HIR function, but perhaps simpler would be to make the aquastat
setpoint track exactly with the loop supply temp, which is being reset as
expected. How can AQUASTAT-SETPT-T be set to equal the dynamically
changing value of the circulation loop setpoint? </SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007>Thanks in advance...</SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face="Courier New" color=#0000ff size=2><SPAN
class=613235917-10082007></SPAN></FONT> </DIV>
<DIV align=left>
<DIV align=left><FONT face=Arial size=2></FONT> </DIV><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt">
<DIV><SPAN
style="FONT-SIZE: 10pt; COLOR: gray; FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><SPAN
class=212011020-11052004><FONT color=#000000>Brandon Nichols,
PE</FONT></SPAN></SPAN></DIV>
<DIV><SPAN
style="FONT-SIZE: 10pt; COLOR: gray; FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><SPAN
class=212011020-11052004><FONT
color=#000000>Mechanical</FONT></SPAN></SPAN></DIV>
<DIV><SPAN
style="FONT-SIZE: 10pt; COLOR: gray; FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><FONT
color=#000080><STRONG>HARGIS ENGINEERS</STRONG></FONT></DIV>
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style="FONT-SIZE: 10pt; COLOR: gray; FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><FONT
color=#515151>600 Stewart Street</FONT></SPAN></P>
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style="FONT-SIZE: 10pt; COLOR: gray; FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><FONT
color=#515151>Suite 1000</FONT></SPAN></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN
style="FONT-SIZE: 10pt; COLOR: gray; FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><FONT
color=#515151>Seattle, WA 98101<o:p></o:p></FONT></SPAN></P>
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style="FONT-SIZE: 10pt; COLOR: gray; FONT-FAMILY: Arial; mso-bidi-font-size: 12.0pt"><FONT
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<DIV> </DIV></DIV>
<DIV><FONT face="Courier New" color=#0000ff size=2></FONT> </DIV><PRE>
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