Re: [EnergyPlus_Support] Daylight

[Rob Hitchcock <RJHitchcock@xxxxxxx>]

Fábyo,

I have looked at your input file with two reference points defined in 
each zone.  I note that you are located in Brazil and have clerestory 
windows on the north and west walls.  It is only the reference points 
that are on the west side of your westernmost zones that are seeing the 
high illuminances from 4-6pm during your summer design days (Dec-Mar).  
As I move these reference points from side to side, I see the high 
values move to slightly later or earlier times in these days.  I have 
been told that the exterior solar data for design days is based on your 
input Sky Clearness factor, which for your summer design days is 1.0 
(completely clear).  Exterior illuminance in lux for direct sunlight can 
easily be in the tens of thousands range.  I would say that these 
particular reference points are simply getting blasted by direct 
sunlight at these hours of these summer design days.

I also noted that you are getting zero illuminance values during your 
winter design day (July) for all hours.  This is due to the fact that 
you have input 0.0 for your winter design day Sky Clearness, which means 
no solar.

Rob Hitchcock
=================

Fábyo Luiz Pereira wrote:

>    I´m trying to simulate a daylight example and have some doubts:
> - "Minimum input power fraction for continuous dimming control"
> (Daylighting:Detailed): This fraction is relative to the "Design Level"
> (Lights)?
> - "Total daylighting reference points" (Daylighting:Detailed): I´m 
> afraid that
> can't use 2 reference points, cause the "Daylight Illum at Ref Point" 
> Report is
> giving, for some hours, nonsense values like 29000 lux. When I 
> simulate the
> same building with only 1 reference point the results for this report 
> seems to
> be acceptable (maximum value about 2500 lux).
> - In my case, I´m using 3025 W of light design level per zone (each 
> one have
> about 150 m2 of floor area), with visible fraction equal to 0.35. This 
> way, can
> I estimate a value for my "Illuminance setpoint at first reference point"
> (Daylighting:Detailed)? I´m using the default value for this variable (500
> lux), and I know that usually we choose that based on a table, but I´m 
> not sure
> that my power design level can be able to give this illuminance. For my
> viewpoint, knowing the light's visible fraction and the floor area I 
> can find a
> illuminance level. Is that right?
>
> =====
> ________________________________________________________
> Engº Fábyo Luiz Pereira
> UFRGS - Laboratório de Vapor e Refrigeração
> Rua Sarmento Leite, 425 - Sala 203 - Centro - 90050-170
> Fone / Fax: +55 51 3316-3167 / 3316-3355
> www.mecanica.ufrgs.br/lafrig
> Porto Alegre - RS - BRASIL
>
>
>      
>      
>            
> _______________________________________________________
> Yahoo! Acesso Grátis - navegue de graça com conexão de qualidade! 
> Acesse: http://br.acesso.yahoo.com/
>
>
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
>
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
>
> Attachments are not allowed -- please post any files to the 
> appropriate folder in the Files area of the Support Web Site.
>
>
>
> Yahoo! Groups Sponsor
> ADVERTISEMENT
> <http://us.ard.yahoo.com/SIG=129gtrf09/M=295196.4901138.6071305.3001176/D=groups/S=1705007389:HM/EXP=1091647175/A=2128215/R=0/SIG=10se96mf6/*http://companion.yahoo.com> 
>
>
>
> ------------------------------------------------------------------------
> Yahoo! Groups Links
>
>     * To visit your group on the web, go to:
>       http://groups.yahoo.com/group/EnergyPlus_Support/
>        
>     * To unsubscribe from this group, send an email to:
>       EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
>       <mailto:EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx?subject=Unsubscribe>
>        
>     * Your use of Yahoo! Groups is subject to the Yahoo! Terms of
>       Service <http://docs.yahoo.com/info/terms/>.
>
>


[Non-text portions of this message have been removed]



------------------------ Yahoo! Groups Sponsor --------------------~--> 
Make a clean sweep of pop-up ads. Yahoo! Companion Toolbar.
Now with Pop-Up Blocker. Get it for free!
http://us.click.yahoo.com/L5YrjA/eSIIAA/yQLSAA/dkFolB/TM
--------------------------------------------------------------------~-> 

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/