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Dear All, <br>
Those of you who are also subscribed to the BLDG-SIM mailing list
perhaps saw a discussion last week concerning a bug in the DOE-2 report
that is generated by Window 5.2. Since this is the same program and same
output format that is used as the basis of TRNSYS's Type56 window model,
we thought it might be useful to let you all know that the bug in Window
5 does not affect our w4-lib.dat file. According to Transsolar:<br><br>
The Type56 window model does not use the U-values from the DOE2 report.
The U-value is instead calculated within Type56 as a function of the
temperature of gas layers within the window. The convective heat transfer
coefficient is an input either from the .bui file or from an INPUT to
Type56. The U-value from the DOE2 report is displayed in TRNBuild but
this value is superceded by the internally calculated value.<br><br>
The following is the bug report from the BLDG-SIM mailing list:<br><br>
<blockquote type=cite class=cite cite=""><font face="arial" size=2>Anyone
using Window 5 (any version) to create custom glazing for DOE2
simulations should be very careful. There is a bug in the output
feature of Window 5 that incorrectly reports the window film coefficients
used to calculate the center of glass U-value. If you use this data
in a DOE 2 simulation the calculated center of glass U-value may be off
by as much as 40%. BE CAREFUL and check the output reports to
verify glazing performance if you are importing Window 5 performance
data. Apparently Window 4 does not have this problem, it worked
fine when I tried it. </font></blockquote><br>
and the reply:<br><br>
<blockquote type=cite class=cite cite="">
<font face="arial" size=2 color="#000080">Thanks for pointing this out.
This is a known bug in WINDOW5. However, you can still use WINDOW5
with a little modification. The methodology for calculating inside heat
transfer coefficient was changed in WINDOW5 where radiative and
convective part of film coefficients are calculated separately but the
DOE2 output report from WINDOW5 only reports convective
part.</font></blockquote><br>
Kind regards, <br>
David <br>
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Thermal Energy System Specialists (TESS), LLC <br>
David
BRADLEY
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Phone: (608) 274-2577 USA <br>
Fax: (608) 278-1475 <br>
E-mail: bradley@tess-inc.com <br>
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and
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