I am wondering if this method seems appropriate for
determining the U-value of glazing combined with framing. For my purposes I am
not concerned with meeting LEED criteria I am just wondering if there is
anything that is wrong or overlooked with this method.
Method:
Based on whatever information I have on the window I
recreate it the best I can in WINDOW 6.3 which allows for SHGC values at
different angles as well as a combined U-value which can be put into a DOE2 report. However eQUEST will only import
the glazing information (haven?t found a way around this) which gives me the
SHGC at different angles based on glazing however the U-value does not include
framing. So, I go back into WINDOW 6.3 and tell it to generate a detailed
report which tells me the combined U value of glazing and framing among other
things. I then go into my eQUEST .inp file and edit the U value in the Glass
type code.
"Exterior Glazin" = GLASS-TYPE-CODE
DESCRIPTION = *Exterior Glazin*
NLAYER = 2
GAPS-THICK = ( 12.7, 0, 0, 0 )
GAPS-COND = ( 0.02407, 0, 0, 0 )
GAPS-DCOND = ( 7.76, 0, 0, 0 )
GAPS-VISC = ( 1.722, 0, 0, 0 )
GAPS-DVISC = ( 4.94, 0, 0, 0 )
GAPS-DENS = ( 1.292, 0, 0, 0 )
GAPS-DDENS = ( -0.0046, 0, 0, 0 )
GAPS-PR = ( 0.72, 0, 0, 0 )
GAPS-DPR = ( -0.0002, 0, 0, 0 )
TSOL = ( 0.245, 0.246, 0.243, 0.238,
0.231, 0.219, 0.191,
0.139,
0.064, 0, 0.204 )
TVIS = ( 0.638, 0.642, 0.633, 0.621,
0.605, 0.572, 0.5, 0.362,
0.168, 0,
0.532 )
ABS-1 = ( 0.216, 0.219, 0.223, 0.226,
0.226, 0.227, 0.234,
0.236,
0.191, 0, 0.223 )
ABS-2 = ( 0.016, 0.017, 0.017, 0.017,
0.017, 0.017, 0.017,
0.015, 0.011, 0, 0.016 )
RBSOL-HEMI = 0.392
RBVIS-HEMI = 0.205
SHDCOF = 0.303
PANES-TIR = ( 0, 0, 0, 0, 0 )
PANES-EMIS-F = ( 0.838, 0.84,
0, 0, 0 )
PANES-EMIS-B = ( 0.018, 0.84,
0, 0, 0 )
PANES-THICK = ( 5.7, 5.7, 0, 0, 0 )
PANES-COND = ( 176.6, 175, 0, 0, 0 )
U-CENTER = 2.155
<<<<<<<<<<<<<<<<<<<<<<<<<<<<< I CHANGE THIS !!!!
GAPS-FILL = ( Air, Air, Air, Air )
PANES-ID = ( 5439, 103, 0, 0, 0 )
..
I change U-CENTER to the U value given to me by WINDOW 6.3. Does
everything seem appropriate? I am trying to avoid using simplified method for
glazing.
Also when I run the simulation and look at the SIM report
section LV-H Details of Windows I find the CENTER-OF-GLASS U-VALUE to be much lower
than the value WINDOW 6.3 came up with. What kind of further calculations does
eQUEST do with the U-value I have provided to come up with the U-value shown in
the report?
Any input would be greatly appreciated. Thanks.
John
Hello John,
I found some information that may be useful to you in the DOE2
Engineering manual. As you can see in the screen shot below there is a
general explanation the algorithm, and in step three they specify the
use of the U-value and the outside film coefficient, which I think is
causing the variation with your reported window U-Value. eQUEST/DOE2
does the same thing with exterior wall reported U-Values as well.
http://doe2.com/download/DOE-21E/DOE-2EngineersManualVersion2.1A.pdf
Byron D. Burns, EIT, BEMP
Sorry I should have made it clear that I am modifying an
existing DOE2.1e file done in EE4 which does not include any information on
framing. I am therefore attempting to lump framing u-value in with glazing
u-value to save the effort of defining window frames one by one, which isn?t so
bad and its what I ended up doing.
But came across an interesting problem with imported
glazings from WINDOW6.3. When I compare glazing done in WINDOW6.3 with the same
glazing from the eQUEST library I get different center of glass U-values
reported in LV-H section of the SIM file. I constructed SB 70XL on Starphire/Air/Clr
6 in WINDOWS6.3 and imported it into eQUEST, all the glazing properties were
approximately consistent with the values from the library glazing however when
I simulate and look at the report I get a center of glass U-value of 0.290 for
the SB 70XL on Starphire/Air/Clr 6 glazing from eQUEST library but a U-value of
0.223 for the glazing created in WINDOW6.3. What am I missing here?
Furthermore, when I edit the .inp file to hard code a
U-value of 0.849 into the library glazing and my WINDOW6.3 glazing like so,
"Type H Door" = GLASS-TYPE-CODE
LIBRARY-ENTRY
"SB 70XL on Starphire/Air/Clr 6"
U-CENTER = 4.822
<<<<<<<<<<<<<<<<<
..
"Type H Door Glazing" = GLASS-TYPE-CODE
DESCRIPTION = *Curtain Wall*
NLAYER = 2
GAPS-THICK = ( 12.7, 0, 0, 0 )
GAPS-COND = ( 0.02407, 0, 0, 0 )
GAPS-DCOND = ( 7.76, 0, 0, 0 )
GAPS-VISC = ( 1.722, 0, 0, 0 )
GAPS-DVISC = ( 4.94, 0, 0, 0 )
GAPS-DENS = ( 1.292, 0, 0, 0 )
GAPS-DDENS = ( -0.0046, 0, 0, 0 )
GAPS-PR = ( 0.72, 0, 0, 0 )
GAPS-DPR = ( -0.0002, 0, 0, 0 )
TSOL = ( 0.245, 0.246, 0.243, 0.238,
0.231, 0.219, 0.191,
0.139,
0.064, 0, 0.204 )
TVIS = ( 0.638, 0.642, 0.633, 0.621,
0.605, 0.572, 0.5, 0.362,
0.168, 0,
0.532 )
ABS-1 = ( 0.216, 0.219, 0.223, 0.226,
0.226, 0.227, 0.234,
0.236,
0.191, 0, 0.223 )
ABS-2 = ( 0.016, 0.017, 0.017, 0.017,
0.017, 0.017, 0.017,
0.015,
0.011, 0, 0.016 )
RBSOL-HEMI = 0.392
RBVIS-HEMI = 0.205
SHDCOF = 0.35
PANES-TIR = ( 0, 0, 0, 0, 0 )
PANES-EMIS-F = ( 0.838, 0.84,
0, 0, 0 )
PANES-EMIS-B = ( 0.018, 0.84,
0, 0, 0 )
PANES-THICK = ( 5.7, 5.7, 0, 0, 0 )
PANES-COND = ( 176.6, 175, 0, 0, 0 )
U-CENTER = 4.822
<<<<<<<<<<<<<<<<<
GAPS-FILL = ( Air, Air, Air, Air )
PANES-ID = ( 5439, 103, 0, 0, 0 )
..
I again get different U-values reported in LV-H section,
0.855 for edited library glazing and 0.464 for WINDOW6.3 edited glazing. These
values should have air film accounted for already so I?m not quite sure what is
causing the discrepancy.
Thanks
Subject: RE: [Equest-users] window, framing combined U-value
Date: Thu, 25 Oct 2012 07:42:03 -0400