[BLDG-SIM] Simplied windows and glass libraries

[Michael Tillou]

Kevin,
 
ASHRAE 90.1 defines the window performance of the entire window assembly
which includes both the frame and glass.  DOE2.2 requires that you enter
glass performance and frame performance separately.  DOE 2.2 has libraries
of GLASS performance which means you still have to define the frame
performance.  The WINDOW software does not export frame performance into
DOE2.2 only the glass performance.  You would input any frame performance
you calculate using THERM directly into DOE2.2 as FRAME-CONDUCTANCE and
FRAME-WIDTH.
 
There is no library of baseline glass because every window assembly has
different performance based on the differences in frame and glass area.  The
best you can do is select baseline glass performance and baseline frame
performance so that the area-weighted performance of all the window
assemblies in your project equals the baseline window performance criteria
(ie U-value and SHGC) from whatever code (ie. ASHRAE 90.1) your modeling.

 
Charlie,
Does Energy Plus allow you to import FRAME performance from the WINDOW
software?      
 
 
Mike
 
 
Michael Tillou, PE, LEED
Tillou Engineering, LLC
Williamstown, MA 01267
P: 413-458-9870 C: 413-652-1087

  _____  

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Kevin Kyte
Sent: Monday, September 17, 2007 11:38 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Simplied windows and glass libraries



Is there a library of baseline windows available?  Perhaps one that may
compare a performance window to an ASHRAE standard.  This sounds like
something that would be very useful.  Instead of using inaccurate baseline
models for government incentive programs and LEED certifications.  

 

From: D. Charlie Curcija [mailto:curcija at ecs.umass.edu] 
Sent: Wednesday, April 25, 2007 9:22 AM
To: kkyte at robsonwoese.com; BLDG-SIM at gard.com
Subject: RE: [BLDG-SIM] Simplied windows and glass libraries

 

Kevin,

 

The best way to accurately model windows is with WINDOW and THERM software
(windows.lbl.gov).  These tools are also used for NFRC (National
Fenestration Rating Council) certifications.  However, you will need all of
the details of frame and glazing design to be able to utilize these tools.
WINDOW program is used to model glazing system and THERM program is used to
model frame and edge of glass sections.  The whole product is then assembled
again in WINDOW program, so WINDOW has dual role.  While WINDOW program is
easy to learn and can be accomplished in half a day, THERM program requires
2-3 days of training for novice users.  Several companies offer training and
our company (www.designbuildersoftware.com) is one of them.  WINDOW program
creates DOE2 report file, which can be used with DOE 2.2 to assign windows.
That provides the most accurate way to model windows energy performance in a
building.

 

If you don't have all of the details and wish to get estimated performance,
you can use one of the predefined windows in DOE 2.2, closest to what you
have.  You should not use simplified way (i.e., by assigning simple
U-factor, SHGC and VT as single number), because that produces gross errors.
EnergyPlus program, which is newer generation energy simulation engine from
DOE does not even have an option to specify windows and doors that way.  You
have to have WINDOW EnergyPlus report file (equivalent to DOE2 report file)
or use one of predefined windows in EnergyPlus.  Our tool DesignBuilder uses
EnergyPlus simulation engine, so you can try it out.

 

If you have further questions, you can contact us directly.

 

Regards,

Charlie Curcija

 

 

  _____  

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Kevin J.
Kyte
Sent: Tuesday, April 24, 2007 11:05 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Simplied windows and glass libraries

Can anyone offer advice on the most accurate route to model window
performance?

There are discrepancies between modeling glazing from doe library and then
modeling those values in simplified mode.

Is this steady state vs. transient heat transfer?  I am not familiar and I
could use a lesson in thermo.

Is this discussed in the Engineer's Manual?  How about if I used Window5?
Will I be able to import Window files into Doe2.2?

 

 

 

I would be grateful of any assistance.

 

Kevin

 

 

 
 
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