[Radiance-openstudio] OpenStudio on OSX 10.8

[Khalid]

Thanks Rob, for the information.
Regarding the Daylight Factor, the following discussion was in a paper I
read several years ago;
	"the average daylight factor .. is a useful design aid which is also
simple to use. Since the daylight distribution and intensity inside the
building will vary with time, whichever sky distribution is used as a basis
for design, then it would seem that great precision in this is
unnecessary..............  I have strong reservations over the provision of
detailed and complex daylight prediction system. What is required, in my
opinion, is a relatively simple system that architects must be encouraged to
use and to combine this with the provision of daylight controls to adjust
the daylight conditions when necessary. Electronic control of the electric
lighting 	should then  integrate the electric lighting with the
daylighting for an energy-efficient design." (David Loe, in the discussion
in reference (1)).
As an architect I believe the daylight factor is more than a metric, and I
do think that its use in different climatic conditions could be improved.

Thanks

1- Kittler 1994 Kittler R. The Need for Standard Skies and Models for Energy
Conservation Measures. Lighting Research and Technology 1994;26(4):171-180.


-----Original Message-----
From: Guglielmetti, Robert [mailto:Robert.Guglielmetti at nrel.gov] 
Sent: Friday, November 16, 2012 7:11 PM
To: Discussion of Radiance with OpenStudio
Subject: Re: [Radiance-openstudio] OpenStudio on OSX 10.8

Hi Khalid,

Actually, if you check the "Use Radiance..." box in OpenStudio, then
Radiance will be used for all the daylighting calculations. That's why it's
important to review the "radout.sql" file for the daylighting data, when
Radiance is used.

The sky condition is derived automatically from the weather file. This is
the beauty of what John Mardaljevec calls "climate based daylight modeling",
or CBDM. The sky condition for each timestep is based on the Perez
all-weather sky model, which simply takes direct normal and diffuse
horizontal flux (irradiance or illuminance) as input. It is the ratio of
those two values that dictates the sky condition.

Daylight factors are computed from overcast sky daylight availability only.
This misses a lot of prevalent sky conditions, and as such is a pretty
useless metric for many climates. Hence, the move to CBDM which we have
embraced in OpenStudio (as have Christoph Reinhart, Alstan Jakubiec, and
Kera Lagios with DIVA, Rick Mistrick with the new DAYSIM, et al.).

Are we having fun yet, Khalid? =8-)

Rob Guglielmetti
National Renewable Energy Laboratory (NREL) Commercial Buildings Research
Group
15013 Denver West Parkway MS:RSF202
Golden, CO 80401
303.275.4319
robert.guglielmetti at nrel.gov






On 11/15/12 10:53 PM, "Khalid" <khalid.ud at gmail.com> wrote:

>Hi, Rob
>Regarding the sky condition in radiance which come with openstudio, is 
>there is a way to select the type of sky condition (clear, overcast, 
>...) As far as I knew the illuminace map will be generated by 
>EenergyPlus based on the weather file, is there is a way have the 
>result as a function of sky type, as done in daylight factor 
>Calculation?
>
>Thanks
>-----Original Message-----
>From: Rob Guglielmetti [mailto:rob.guglielmetti at gmail.com]
>Sent: Thursday, November 15, 2012 4:13 AM
>To: Discussion of Radiance with OpenStudio
>Subject: Re: [Radiance-openstudio] OpenStudio on OSX 10.8
>
>Hi Khalid,
>
>THat would be great if you're willing to give it a try! I don't know 
>that there are a lot of people trying out the Linux version. Ubuntu is 
>what we develop and test on, too.
>
>- Rob
>
>ease Date: 11/14/12
>
>
>_______________________________________________
>Radiance-openstudio mailing list
>Radiance-openstudio at radiance-online.org
>http://www.radiance-online.org/mailman/listinfo/radiance-openstudio


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