[esp-r] Re: again about Radiance (Gian Luca Brunetti)

Wed Sep 14 10:57:18 BST 2011

Alle martedì 13 settembre 2011, esp-r-request at lists.strath.ac.uk ha scritto:
> Send esp-r mailing list submissions to
> 	esp-r at lists.strath.ac.uk
> 
> To subscribe or unsubscribe via the World Wide Web, visit
> 	http://lists.strath.ac.uk/mailman/listinfo/esp-r
> or, via email, send a message with subject or body 'help' to
> 	esp-r-request at lists.strath.ac.uk
> 
> You can reach the person managing the list at
> 	esp-r-owner at lists.strath.ac.uk
> 
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of esp-r digest..."
> 
> 
> Today's Topics:
> 
>    1.  again about Radiance (Gian Luca Brunetti)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Tue, 13 Sep 2011 16:56:42 +0200
> From: Gian Luca Brunetti <gianluca.brunetti at polimi.it>
> Subject: [esp-r]  again about Radiance
> To: esp-r at lists.strath.ac.uk, gianluca.brunetti at polimi.it
> Message-ID: <4E6F6F2A.2040804 at polimi.it>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Dear list,
> I am writing again about the ESP-r Radiance interaction.
> 
> I August while away from my computer I optimistically posted a couple of
> messages here in which I reasoned about the possibility to modify the
> insolation values in the .shda files taking into account the illuminance
> values produced by Radiance at each time step. (This by using a ratio of
> the illuminance levels calculated with solar obstruction as black bodies
> and the illuminance levels calculated with their true reflectances.)
> 
> Now inspecting the interface to Radiance in ESP-r, which I only
> previously used for daylight factors calculations, I have seen that in
> the interactive set-up is a menu entry for the ESP-r - Radiance coupling
> and another for the calculation of daylight coefficient.
> 
> I also saw the 1998 article  by Clarke and Janak "Simulating the Thermal
> Effects of Daylight-controlled Lighting" (Building Performance, 1998).
> 
> About the coupling mode, I think I have understood that it comes close
> to my needs to take into account the effect of reflections by external
> obstructions; but also that this operation only obviously regards just
> illuminance levels, without effect on solar gains.
> 
> And about the daylight coefficient calculations, I think I have
> understood that each set of them belongs to a specific position in time.
> 
> It doesn't help my understanding that I am not able to run the two
> operations, nor the one, nor the other. (Incidenlty, I also have not
> been able to run the operations to obtain glare evaluations, which I
> presently am not longing for.)
> 
> I imagine that there must be some Radiance files to write or modify to
> place sensors at surfaces or else, but I have no clue about where to
> start; and I also most fundamentally suspect that I am not on the right
> track at a more general level.
> 
> That said, running the two above described operations has just
> indirectly to do with present aim, and might be not essential for me. My
> priority is to find a way to extract grids of illuminance levels for
> each opaque internal surface from the  rendering operations, to obtain
> the mean illuminance levels for each of them. (Morevoer, relative
> differences of illuminance from surface to surface would be enough for
> my needs - I woun't necessarily need absolute values; and relative
> values might even be inferred from to-be-rendered colors.)  But the
> Radiance rendering options I have seen produce graphical results, not
> textual.
> 
> About all this, I poke in the source of the Radiance's file "dayfact",
> which is there presented as being able to calculate daylight factors and
> illuminance levels, but I haven't found no clue about the calculation or
> set up needed to request illuminance levels.
> 
> Does anybody using Radiance here have a suggestion about how to obtain
> the mean illuminance level for a certain surface in a certain position
> in time?
> 
> I fear that if I can't perform this most basic operation I'll have to
> throw in the towel.
> 
> Thank you in advance.
> 
> Best regards
> 
> Gian Luca Brunetti
> 
> Politecnico di Milano
> Dipartimento BEST
> via Bonardi 11
> 20133 Milano
> tel./fax 02 2399 5750
> 
> 
> 
> 
> 
> 
> ------------------------------
> 
> _______________________________________________
> esp-r mailing list
> esp-r at lists.strath.ac.uk
> http://lists.strath.ac.uk/mailman/listinfo/esp-r
> 
> End of esp-r Digest, Vol 62, Issue 4
> ************************************

dear Gian Luca

I dare say it is not clear what you are looking for, if you are interested in 
taking into account obstructions reflection for computing solar gains the 
answer is that it is a very interesting work and you can refer to the 
following link

http://www.ibpsa.org/proceedings/BS2003/BS03_0571_576.pdf

but it seems that your questions are more RADIANCE related,  please visit this 
site

http://www.jaloxa.eu/resources/radiance/documentation/index.shtml

the Radiance Tutorial and Radiance Cookbook will be helpful to you and will 
instruct you in how to obtain numerical values.

as far as esp-r, the full Radiance coupling and daylight coefficients  are used 
as a control system for the gains produced by artificial lighting, the setup is 
not straightforward. 

Marco
-- 
 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _   
|Marco Manzan               Email: manzan at units.it      |        
|Tel:   (+39) 040 5583506   Fax  : (+39) 040  572033    |        
|Dipartimento di Ingegneria Meccanica e Navale          |        
|Universita' degli Studi di Trieste                     |        
|via A. Valerio 10, 34127 TRIESTE                       |        
|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|