Re: [EnergyPlus_Support] Windows construction

["Joe Huang" <yjhuang@xxxxxxx>]

Jun Moon,

This is a frequently occurring problem. We here at LBNL have had to address 
this in a project for the California Energy Commission in which most of the 
windows are defined only by U-factor and SHGC (actually Shading 
Coefficient).  We have been using Window-5 (within EnergyPlus)  iteratively 
to produce double-pane layers that match the specified U and SHGC.  At 
present, this is done manually, but eventually we intend to automate the 
process within EnergyPlus, which includes the Window-5 algorithms.

The main problem with this method is that, for the given information, there 
is no unique solution, so we make some generalizing assumptions about the 
optical properties of the glazing. The method that we hope to automate will 
allow a gradation of window descriptions, with the U-factor and SHGC as the 
bare minimum. The more inputs that are available - type and U-factor of 
frame, frame, type of glazing and coating, ratio of reflection to absorption 
of glazing, etc. - the more constrained is the solution and the more closer 
the match to the actual window properties. A major part of this future work 
is to identify which window descriptors or properties are most useful for 
producing an accurate layer.

I'm cc'ing this e-mail to Jeff Warner, who did the manual translation of the 
California Energy Commission window types, and to Dariush Arasteh and 
Christian Kohler of  LBNL's Windows Group, in case they want to add any more 
thoughts to this topic.

Joe Huang

----- Original Message ----- 
From: "hjunmoon" <gt6102a@xxxxxxxxxxxxxxxx>
To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Tuesday, June 21, 2005 10:23 AM
Subject: [EnergyPlus_Support] Windows construction


> Dear All,
>
> I am trying to model a window construction. The data I have are U-
> factor (2.0), SHGC(0.33), and Visible transmittance(0.51) for the
> window system. I do not have detailed data for each layers of glasses
> and thickness.
> Is there a way to model this window without specifying each layers of
> window glasses and air? or Do I have to construct a similar windows
> systems using the dataset in E+?
>
> Thanks in advance
>
> Jun Moon
>
>
>
>
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
>
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
>
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> folder in the Files area of the Support Web Site.
>
> Yahoo! Groups Links
>
>
>
>
>
>
> 



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