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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hi all<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I realize that a new guidance document was released about a
month ago for dealing with District Thermal System, but I am in the process of
wrapping up a project that is using v1.0 of the Guidance for District Thermal
Systems, and I am getting a result that is really confusing me. I
apologize if this is repetitive, but I have browsed through the archives, and
while there was a lot of discussion on the DES Guidance document, none of it
seemed to address this particular issue I am having. This project is
registered under <st1:place w:st="on"><st1:City w:st="on">LEED</st1:City> <st1:State
w:st="on">NC</st1:State></st1:place> v2.2.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>For my project, I modeled the first step as outlined in the document,
with both the baseline and proposed models using the central steam plant for
heating (cooling is covered by DX coils). For this step, I am seeing
approximately a ~19% energy cost saving over the baseline model, well over the minimum
14% required savings.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>However, when I implement step 2 of the guidance, I set up
the baseline boilers as normal, and then set up a boiler for the proposed model
using the efficiency of the generating plant, accounting for thermal losses as
discussed in the document. The central plant has an efficiency of
approximately 85%, and coupled with the thermal losses of 15% for a closed loop
steam system, I am looking at an overall efficiency of about 73% for the
virtual steam boiler in the proposed model. The boiler in the baseline
model has an efficiency of 80% per 90.1. So, since the efficiency of the
proposed boiler is lower than the baseline boiler, it should come as no
surprise that the energy savings are considerably lower, and since the building
has high heating and service hot water loads, the overall energy cost savings
reduces to about 9%.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>My question is, does this make sense? I realize that
the intention of the document is to penalize buildings that use inefficient
central plants, but it doesn’t make much sense to me that I am seeing
such a drop off in the overall result. Am I interpreting something in the
document wrong, or setting something up incorrectly? Or, is this the
expected result with a Central Plant operating at 85% efficiency? It
seems like a plant would have to be near 100% efficiency to see much additional
benefit from using a central steam plant if this is the case.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thank you all for your help<o:p></o:p></span></font></p>
<p class=MsoNormal><b><font size=1 color="#009e49" face=Arial><span
style='font-size:9.0pt;font-family:Arial;color:#009E49;font-weight:bold'>Adam
A. Gonthier</span></font></b><o:p></o:p></p>
<p class=MsoNormal><em><b><i><font size=1 color="#009e49" face=Arial><span
style='font-size:9.0pt;font-family:Arial;color:#009E49;font-weight:bold'>Energy
Engineer</span></font></i></b></em><b><i><font size=1 color="#009e49"
face=Arial><span style='font-size:9.0pt;font-family:Arial;color:#009E49;
font-weight:bold;font-style:italic'><br>
</span></font></i></b><font size=1 color="#827f78" face=Arial><span
style='font-size:9.0pt;font-family:Arial;color:#827F78'>Horizon Engineering
Associates, LLP</span></font><font size=1 face=Arial><span style='font-size:
9.0pt;font-family:Arial'><ns0:PostalCode w:insAuthor="agonthier"
w:insDate="2010-09-21T16:25:00Z" w:endInsAuthor="agonthier"
w:endInsDate="2010-09-21T16:25:00Z"></ns0:PostalCode><font color="#827f78"><span
style='color:#827F78'><o:p></o:p></span></font></span></font></p>
<p class=MsoNormal><font size=1 color="#827f78" face=Arial><span
style='font-size:9.0pt;font-family:Arial;color:#827F78'>T: 646.442.1131</span></font><font
size=1 color="#009e49" face=Arial><span style='font-size:9.0pt;font-family:
Arial;color:#009E49'><br>
C:</span></font><font size=1 color="#827f78" face=Arial><span lang=FR
style='font-size:9.0pt;font-family:Arial;color:#827F78'>347.297.9005</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'><a
href="http://www.horizon-engineering.com/"
title="http://www.horizon-engineering.com/"><font size=1 color="#009e49"
title="http://www.horizon-engineering.com/"><span
title="http://www.horizon-engineering.com/"><span
title="http://www.horizon-engineering.com/"><span lang=FR style='font-size:
9.0pt;color:#009E49'>www.horizon-engineering.com</span></span></span></font></a></span></font><font
size=1 color="#009e49" face=Arial><span style='font-size:9.0pt;font-family:
Arial;color:#009E49'><br>
<br>
<b><i><span style='font-weight:bold;font-style:italic'>Demand a Higher Standard</span></i><br>
</b></span></font><font size=2 color=green face=Arial><span style='font-size:
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http://www.p/">P</span></span></span></font></span></a></span></font><b><font
size=1 color=green face=Arial><span style='font-size:9.0pt;font-family:Arial;
color:green;font-weight:bold'> </span></font></b><font size=1 color="#009e49"
face=Arial><span style='font-size:7.5pt;font-family:Arial;color:#009E49'> </span></font><font
size=1 color="#009e49" face=Arial><span style='font-size:8.0pt;font-family:
Arial;color:#009E49'>Please consider the environment before printing this
e-mail</span></font><font size=1 color="#009e49" face="Arial Narrow"><span
style='font-size:9.0pt;font-family:"Arial Narrow";color:#009E49'> </span></font><o:p></o:p></p>
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