Opened 2 years ago

Last modified 2 years ago

#1012 task

Lower-SHGC window options for 2012 IECC

Reported by: ewilson Owned by: ewilson
Priority: normal Component: Modeling - New Options
Version: 3.0.0.0 Keywords: windows
Cc: shorowit, cchriste

Description

The 2012 IECC requires SHGC <= 0.25 in zones 1–3. The lowest we have in BEopt is 0.27 (3-pane insulated frame).

http://www.greenbuildingadvisor.com/sites/default/files/2012%20IECC%20-%20Window%20requirements%20table%20-%20corrected.jpg

Attachments (1)

BEopt window options2.txt (967 bytes) - added by cchriste 2 years ago.

Download all attachments as: .zip

Change History (12)

comment:1 Changed 2 years ago by shorowit

  • Version changed from Future to 2.4.0.2 Final

comment:2 Changed 2 years ago by shorowit

  • Owner set to ewilson
  • Status new deleted

Can you recommend a window option and cost?

comment:3 Changed 2 years ago by ewilson

  • Owner changed from ewilson to shorowit

I propose I recommend changing the SHGC to 0.18 for all Low-Gain options. Source: http://www.efficientwindows.org/

I spot checked the High-Gain options and they still look appropriate.

comment:4 Changed 2 years ago by cchriste

On a related note, I would recommend revising the SHGC variable note, replacing:

"SHGC: The ratio of solar heat gain through a glazing system compared to that of an unobstructed opening. The SHGC is air-to-air for the entire window assembly including glazing (with edge spacer effects) and frame under NFRC rating conditions."

with:

"SHGC: The ratio of solar heat gain through a glazing system compared to that of an unobstructed opening. The SHGC is for the entire window assembly including glazing and frame under NFRC rating conditions."

comment:5 Changed 2 years ago by ewilson

  • Owner changed from shorowit to ewilson

Eric and Craig will check how the existing options were developed Wednesday morning. Eric will also propose updated values for Medium Gain options.

comment:6 Changed 2 years ago by cchriste

Also, is there a reason to have Frame as a calculated display variable, in addition to Frame Material as a simulation variable? It seems redundant.

comment:7 Changed 2 years ago by shorowit

It's for the same reason that U-Value and SHGC are also duplicated -- options can have facade-specific values, so we either show the single value as a display value or show "[mult]".

Changed 2 years ago by cchriste

comment:8 Changed 2 years ago by cchriste

1) Yes, I saw the 'multi' for option with facade-specific windows. I guess it's OK, but having the mostly redundant columns so nearly adjacent to each other acerbates the problem for the Frame / Frame Material columns. Maybe they should at least have identical names for consistency.

2) Suggested new option names (also in attachment):

Clear, Single, Metal
Clear, Single, Non-metal
Clear, Double, Metal, Air,
Clear, Double, Thermal-Break, Air
Clear, Double, Non-metal, Air
Low-E, Double, Non-metal, Air, H-Gain
Low-E, Double, Non-metal, Air, M-Gain
Low-E, Double, Non-metal, Air, L-Gain
Low-E, Double, Non-metal, Arg, H-Gain
Low-E, Double, Non-metal, Arg, M-Gain
Low-E, Double, Non-metal, Arg, L-Gain
Low-E, Double, Insulated, Air, H-Gain
Low-E, Double, Insulated, Air, M-Gain
Low-E, Double, Insulated, Air, L-Gain
Low-E, Double, Insulated, Arg, H-Gain
Low-E, Double, Insulated, Arg, M-Gain
Low-E, Double, Insulated, Arg, L-Gain
Low-E, Triple, Non-metal, Air, H-Gain
Low-E, Triple, Non-metal, Air, L-Gain
Low-E, Triple, Non-metal, Arg, H-Gain
Low-E, Triple, Non-metal, Arg, L-Gain
Low-E, Triple, Insulated, Air, H-Gain
Low-E, Triple, Insulated, Air, L-Gain
Low-E, Triple, Insulated, Arg, H-Gain
Low-E, Triple, Insulated, Arg, L-Gain

comment:9 Changed 2 years ago by shorowit

1) I'm going to remove all 3 display columns. They don't provide any value anymore. They were helpful back when BEopt defaulted to not showing these 3 property columns, but now that we do, they are just confusing/redundant.

comment:10 Changed 2 years ago by shorowit

r5824. Updated window option names. Removed display columns.

comment:11 Changed 2 years ago by shorowit

  • Priority changed from low to normal
  • Version changed from 2.5.0.0 to 2.6.0.0

Need to defer question of new/modified options.

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