I have recently inherited the task of finishing an eQuest model (and I have
never used eQuest) that someone else has started for LEED EAc1. We have
received comments form the LEED reviewer, one being:
1. Windows and skylights for the Proposed Case were modeled with a U-value
of 0.32, which does not appear to account for the impact of the window
frames on the whole assembly as required by ASHRAE modeling protocol. Please
provide additional information to confirm that the framed assembly U-value
was used, or revise the model to reflect framed assembly U-values as shown
in ASHRAE 90.1-2004 Table A-8.2.
I have looked through the "Modeling Procedures Quick Reference Guide" and
while it states you can edit or add window types in detailed mode, it skips
over how to edit them. Can anyone give me some direction on how to proceed?
Thanks for the help.
Scott
I have received the follow Technical Advice/review comment regarding window
U-values
"It is unclear whether the window U-value of 0.40 used for the Proposed Case
accounts for the impact of the window frames on the whole assembly as
required by ASHRAE modeling protocol. Please provide additional information
to confirm that the framed assembly U-value was used for the Proposed Case
windows (e.g. showing that the whole window assembly has been tested by
NFRC, or verifying that LBNL Window5 calculations have been provided for the
whole assembly, or verifying that the frame effects are captured within the
energy modeling software), or revise the model referencing ASHRAE 90.1-2004
Table A8.2 if needed."
Therefore, I plan to run Window5 for each window type. Then I will go into
eQuest, remove the frames from the windows, and enter the Window5 calculated
parameters for each widows. The ASHRAE 90.1-2004 Table A8.2 are terrible
windows, often worse than Table 5.5.
In detail mode, the window properties are separated into two components, the "Glass Type" (listed after all the constructions, layers and materials in the component tree) and the frame width and conductance (associated with each window). For LEED, it is best to zero out all the frame widths and use the window assembly properties in the "Glass Type" definitions. But be careful, in detail mode you must specify the GLASS-CONDUCTANCE, which is the U-factor of the window without including air films. So normally the process would be: obtain NFRC U-factor for the window assembly (or use ASHRAE values), look up the appropriate GLASS-CONDUCTANCE in the table in the DOE2 help file (attached), enter this value into the GLASS-CONDUCTANCE field, finally run the model and check the LV-D report (scroll down for building summary) to make sure that the U-factors of the windows are correct.
Kelsey Van Tassel
I would suggest your guys using window 5 or 6 to model the window and then
export the window into the eQuest. That would be more accurate and simply.
Thanks,
Rongxin
I don't think eQUEST imports full-frame data. Only COG info...