|
Hello:
We are
currently completing a report for the Texas Legislature where we have attempted
to simulate the effects of thermal mass on a "standard" building as defined by
the 2000 IECC. So far, we've spent most of our time trying to define how to
simulate the building, since the 2000 IECC is flawed in that it requires 13.5
lb/ft2 of floor space, which makes the simulation of thermal mass impossible
with DOE-2. (i.e., it forces the use of floor-weight values, which then use
pre-calculated ASHRAE weighting factors, which are not as accurate as custom
weighting factors).
There
are multiple issues with accomplishing this with DOE-2, which our report points
out in some detail. In general the report shows mixed results, with the largest
variation coming from peak value predictions, which is important for Texas and
the Ozone reduction during summertime (i.e.,reduce peak cooling loads). We also
found the following items affect the results: SC vs Window 5 simulation of
windows, Effective-U value and fictitious ground heat transfer
(i.e., Winklemann's memo), placement of the mass has an impact as well
(inside or outside of thermal mass). Finally, the ground temperatures that DOE-2
uses when using a TMY2 tape for a city are suspect (i.e., too cold for Texas in
the summer and winter, average o.k.). I'm hoping to have a synopsis of the
report to pass around at the next 90.1 Envelop meeting and/or TC 4.7 in Kansas
City.
Jeff
8=! 8=) :=)
8=) ;=) 8=) 8=( 8=)
8=() 8=) 8=| 8=)
:=') 8=) 8=) 8=?
Jeff S. Haberl, Ph.D.,
P.E.............................jhaberl@xxxxxxxxxxxx 8=/ 8=) :=) 8=) ;=) 8=) 8=() 8=) :=) 8=) 8=! 8=) 8=? 8=) 8=) 8=0
====================================================== You received this e-mail because you are subscribed to the BLDG-SIM@xxxxxxxx mailing list. To unsubscribe from this mailing list send a blank message to BLDG-SIM-UNSUBSCRIBE@xxxxxxxx |