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<DIV><SPAN class=772490315-08072010><FONT face=Arial size=2>Howdy
folks,</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial size=2>I have always
allowed eQuest to auto-size my domestic hot-water use, and after looking at it,
felt like it was putting me in the ballpark most of the
time.</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial size=2>I have recently come
across a situation, however, that is leaving me puzzled.</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial size=2>I am modeling a
small dormitory/apartment complex at a college campus. This building is
currently served by two Munchkin boilers which provide both domestic hot water
and heating water for the building. The domestic hot water tank is basically on
its own zone valve, and when a call for DHW occurs, the secondary pump in the
heating loop stops so that the boilers' output is strictly focused on the DHW
load. When the DHW load is satisfied, the secondary pump resumes normal
operation and provide heat for the heating load.</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial size=2>Having never modeled
this before, I simply did what I have always done and had eQuest size a DHW
heater for me. Then, after I was done in the wizard, I went to detailed mode
where I used the DHW capacity and schedule created by the wizard and applied
both as a second loop on my boiler heating loop. Granted, I haven't done
anything with the controls yet to model the boilers "shifting" from one load to
the other upon a call from DHW, but I thought I would be in the
ballpark.</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial size=2>I was
wrong.</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial size=2>Please see attached
a plethora of files. I have attached both the original, dedicated DHW heater
model, and the detailed-edit DHW-on-boiler model. I have also attached hourly
reports of the DHW calculated loads and an Excel sheet comparing the gas usage
from one model to the other. There is a significant disparity. I'm trying to
understand how the program can calculate such a different load from one model to
the other considering that I am using the same capacity and same schedule for
the load I have assigned to the boilers. I'm sure whatever it is I'm missing is
straight-forward; nevertheless, I'm missing it.</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial size=2>Your insight, as
always, is appreciated.</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2>Thanks,</FONT></SPAN></DIV>
<DIV><SPAN class=772490315-08072010><FONT face=Arial
size=2>Gary</FONT></SPAN></DIV></DIV><SPAN style="FONT: 8.5pt Arial"><BR><FONT
color=green>_______________________________________________________________________________________________________________________</FONT><BR><BR>
<P style="FONT: 8.5pt Arial" align=left><B>Gary Schrader</B> </B>| <B><FONT
color=green>Schneider Electric </FONT></B>| <B>Buildings Business</B> </B>|
<B>Energy Solutions </B>| <B>Engineer I</B><BR><B>Phone:</B> +1 </B>| <B>Mobile:
</B>+1 913 217 8068</B> | <B>Fax: </B>+1 913 469 0206<BR><B>Email: </B><A
href="mailto:gary.schrader@buildings.schneider-electric.com">gary.schrader@buildings.schneider-electric.com</A>
</B>| <B>Site: </B><A
href="http://www.schneider-electric.com/buildings">www.schneider-electric.com/buildings</A></B>
| <B>Address: </B>16011 College Boulevard, Suite 212, Lenexa, KS 66219,
USA<BR><BR><FONT color=green>*** Please consider the environment before printing
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