RE: [EnergyPlus_Support] thermal and optical properties calculation of facade systems

["Edward G. Lyon" <eglyon@xxxxxxx>]

Sounds like your grid is on the outside and casts a shadow on the window.  A fair approximation is to calculate the glazing alone using Window.  Adjust the exterior wind coefficient if you think the grid creates some shelter for the window. The grid is just a net free area that limits the % of sun light that reaches the glass.  Most of your light transmittance properties are simply the % of calculated values.  Things can be more complex if the grid is almost opaque, and you may need to use CFD for air movement and calculate grid/glass reflections separately.



Having the grid inboard of the glass is also more complicated because of reflections and absorption that are not as simple as just shading the glass from the outside.



Ned Lyon, P.E. (MA)
Staff Consultant

SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct 
781.907.9009 fax
www.sgh.com



From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Emanuele Naboni
Sent: Thursday, February 11, 2010 5:04 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] thermal and optical properties calculation of facade systems





Dear All,



Does any of you have an idea on what software tools could be used to calculate thermal and optical transmission properties (e.g., thermal transmittance, total solar energy transmittance) of a complex window system based on the ISO 15099:2003 method?



The system that I am trying to study is composed by a double pane glass protected by a vertical metal grid which is 750mm (2' 6") detached from the window.