[Radiance-general] Watching the Skies (aka Sky Model Bewilderment)

[Jia Hu]

Hello:

Just add two sources I mentioned:

http://www.radiance-online.org/pipermail/radiance-general/2002-June/000322.html
http://www.radiance-online.org/pipermail/radiance-general/2002-June/000318.html

I do not know the statement in the second one is right or not.

Cheers, Jia



On Fri, Jul 16, 2010 at 6:52 PM, Jia Hu <hujia06 at gmail.com> wrote:

> Hi Randolph:
>
> I do not know what data you have and your reseasrch aim and thus will talk
> about what I know about this issue. I am sure others have better ideas.
> Generally, if you have direct and diffuse irradiation data (you can get real
> time data from your local weather station, check DOE EnergyPlus program),
> you can try Perez model (gendaylit program in Radiance) which determines the
> sky type according to the irradation value (see Perez's paper in 1990).
>
> If you use gensky, you have to specify the sky type. On the other hand, you
> can also try gensky to find a best sky model fitting your measured data.
> When using gensky, it would be better to use measured illuminance values
> rather than measure irradiation value. I remember someone mentioned that the
> irradiation data required by gensky is only visible range (I saw a post
> talking about this)?
>
> Cheers,
> Jia
>
>
> On Fri, Jul 16, 2010 at 6:20 PM, R Fritz <RFritz at lbl.gov> wrote:
>
>> I have a pile of data from an actual test room, with more coming, and a
>> Radiance model under construction. Do people have an opinion as to which sky
>> model might best reflect the actual skies of Berkeley, California? I've got
>> some reading ahead of me, Perez and Shirley and perhaps some CIE documents,
>> but I'm wondering if anyone has perhaps some thoughts or cites to share. The
>> test room is, yes, in Berkeley, California.
>>
>> BTW, I did find the discussion of sky modeling on the list in October of
>> 2003. (If anyone hasn't seen it before, look for entries titled "Sky
>> Definition" in <
>> http://www.radiance-online.org/pipermail/radiance-general/2003-October/date.html
>> >.)
>> --
>>
>>
>> Randolph Fritz • RFritz at lbl.gov
>> Environmental Energy Technologies Division • Lawrence Berkeley Labs
>>
>>
>>
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>>
>
>
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