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<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">Alec,</SPAN><?xml:namespace prefix =
o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><FONT size=3><FONT
face="Times New Roman"> <o:p></o:p></FONT></FONT></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">I think the intent of the code is
exactly to penalize an HVAC system (or equipment) that is less
efficient than the Code one. The choice of local floor DX unit brings about
issues of a less efficient refrigeration, less efficient economizer control
(i.e., waterside vs. air side), that must be offset somewhere else in the
building, i.e. more efficient glazing...Furthermore, nowhere in the code it is
mentioned that the consistent HVAC systems must be used. </SPAN><o:p></o:p></P>
<P class=MsoNormal style="MARGIN: 0in 0in 0pt"><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial">It has been my experience that for
the ecb model an air-side economizer should be used.</SPAN><o:p></o:p></P>
<DIV><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">In
general, the situation you have described is fairly common, and unfortunately
the proposed design building is thus often penalized.</SPAN></DIV>
<DIV><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"></SPAN> </DIV>
<DIV><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">Konstantin
Babets</SPAN></DIV>
<DIV><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">Jaros
Baum and Bolles</SPAN></DIV>
<DIV><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">(212)
530 9455</SPAN></DIV>
<DIV><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"></SPAN> </DIV>
<DIV><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"></SPAN> </DIV>
<DIV><SPAN
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Original Message ----- </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=astevens@dmiinc.com href="mailto:astevens@dmiinc.com">Alec
Stevens</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=BLDG-SIM@gard.com
href="mailto:BLDG-SIM@gard.com">BLDG-SIM@gard.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, July 13, 2004 12:04
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [BLDG-SIM] another 90.1 ECB
question</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Hello,</FONT></DIV>
<DIV><FONT face=Arial size=2>In light of recent questions to the list on the
ASHRAE ECB method, here is one that we are working on: </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The proposed multi-story office building will
have a cooling tower serving a condenser water loop. Each floor has a
VAV air handling unit with a water-cooled DX compressor, heat is rejected
to the CW loop. Economizer cooling is provided on the water side via
separate WSE coils. OA is provided to each floor's AHU, but 100% OA is
not provided. The waterside economizer coils can pre-cool the mixed air
when the CW temperature is low enough, and can run in series with the DX
coils. </FONT></DIV>
<DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regarding the base budget building, the system
map in 90.1 seems to indicate that a central chiller plant is required for
this type of building (System type 2). However, in general I think we
are supposed to use consistent HVAC systems in the base budget building and
the proposed building. I want to know if we can use the floor-by-floor
water cooled units in the base budget building so as to be consistent and to
not penalize the energy performance of the floor-by-floor DX units compared to
a chiller plant.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Also, the language is confusing to us regarding
air vs. water side economizers. In 11.4.3, we are directed to include an
economizer that meets the requirements of 6.3.1, where the standard
seems to indicate that a system must have either air <EM>or</EM> water side
economizers. However, in 11.4.3e, the standard seems to say that system
type 2 must use airside economizers. The proposed design seems to meet
the requirements for waterside economizers, but I don't want to penalize the
proposed design for not having 100% OA capability. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Your thoughts on the above questions would be
appreciated.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks!</FONT></DIV>
<DIV><FONT face=Arial size=2>Sincerely,</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Alec Stevens, PE, LEED AP<BR>DMI<BR>450 Lexington
St, Newton, MA 02466<BR>p: 617-527-1525 x105 f: 617-527-6606<BR>e: <A
href="mailto:astevens@dmiinc.com">astevens@dmiinc.com</A></FONT></DIV></DIV><PRE>
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