[Radiance-general] modeling glazings

[Martin Moeck]

I have been looking for fritted and translucent glazing data and had to resort to trans to model them. They seem not to be part of Optics5, unless I did not search carefully.  Therefore, I just measure glazing properties with luminance and illuminance meters and approximate them with trans. I am not quite sure when optics5 is needed. 
 
Martin
 
 

	-----Original Message----- 
	From: Reinhart, Christoph [mailto:Christoph.Reinhart at nrc-cnrc.gc.ca] 
	Sent: Wed 9/8/2004 9:16 AM 
	To: radiance-general at radiance-online.org 
	Cc: 
	Subject: [Radiance-general] modeling glazings
	
	
	Dear colleagues,
	 
	I know, I know. The topic of modeling glazings in Radiance using Optics 5 data has been extensively discussed in January 2004. I just reread the emails with great interest in the archives. BUT I am still undecided whether to go with Optics 5 is worth the effort. 
	 
	in January, everybody agreed that creating a specific glazing in Optics 5 creates an output as follows:
	 
	#
	# header info
	
	void  glass       TestSystem_glass
	0
	0
	3     0.638     0.647     0.568
	 
	void  BRTDfunc    TestSystem_front
	10
	      0.230     0.263     0.326
	      0.585     0.594     0.521
	      0 0 0
	      .
	0
	9 0 0 0 0 0 0 0 0 0
	 
	void  BRTDfunc    TestSystem_back
	10
	      0.289     0.336     0.371
	      0.585     0.594     0.521
	      0 0 0
	      .
	0
	9 0 0 0 0 0 0 0 0 0
	 
	Philip mentioned that to use this material description, one would need "two glass polygons for each window, one for the front and one for the back". I assume this means:
	 
	TestSystem_front polygon FrontOfWindow
	0 0
	12     0     0     0
	         1     0     0
	        1     1    0
	        0    1    0 
	 
	TestSystem_back polygon BackOfWindow
	0 0
	12     0     0     -0.01
	        0    1    -0.01
	        1     1    -0.01
	        1     0     -0.01 
	         
	Is this correct? How does the glazing know its transmittance, i.e. how does TestSystem_glass come into play? Also, does anybody have any references or experience how much more accurate a simulation gets if one uses the full optics 5 file instead of a stripped down version such as:
	
	
	void  glass       TestSystem_glass
	0
	0
	3     0.638     0.647     0.568
	 
	Any thoughts are elcome,
	 
	Christoph
	Christoph Reinhart, Ph.D.                        tel: (613) 993-9703 
	Research Officer                                      fax: (613) 954-3733 
	Institute for Research in Construction      e-mail: christoph.reinhart at nrc-cnrc.gc.ca 
	National Research Council Canada        1200 Montreal Road M-24, Ottawa 
	Ontario K1A 0R6 Canada 

	Daylighting Analysis Software: 
	The Lightswitch Wizard (initial design)   www.buildwiz.com <http://www.buildwiz.com/lightswitch/index.cfm>  
	DAYSIM (expert software)                       www.daysim.com <outbind://26/www.daysim.com>  <outbind://26/www.daysim.com>  

	IEA Task 31                                            http://www.iea-shc.org/task31/ 

	 

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