[Radiance-general] Experience implementing gendaylit with physical inputs (-G: direct - horizontal irradiance and diffuse - horizontal irradiance)

[Ehsan M.Vazifeh]

HI Kyle,

If you are using a shadow ring to get the diffuse horizontal irradiance you
have to adjust the sliding bar manually around 1 or two times a week
regarding to the documentation. below you will find the link to the Manual
for the shadow ring of Kipp & Zonen.

http://www.kippzonen.com/Download/46/CM-121-B-C-Shadow-Ring-Manual?ShowInfo=true

also, to calculate the direct simply use this formula:

Direct normal irradiance=((Global horizontal irradiance)-(Diffuse
horizontal irradiance))/sin(sun altitude)

Cheers,
Ehsan


On Thu, Apr 10, 2014 at 9:10 AM, Axel Jacobs <jacobs.axel at gmail.com> wrote:

> Hi Kyle,
>
> check out the SPN1 and BF5 from Delta-T:
>
> http://www.delta-t.co.uk/product-category.asp?div=
> Meteorology%20and%20Solar
>
> Very neat, but I have not used them myself.
>
> If you prefer to use two instruments and shading ring instead, you'll need
> to correct for the shading ring:
>
> Rawlins F, Readings CJ (1986) The shade ring correction for measurements
> of diffuse irradiance under clear skies. Solar Energy 37:407-416
>
> Steven MD, Unsworth MH (1980) Shade-ring corrections for pyranometer
> measurements of diffuse solar radiation from cloudless skies. Quart J Royal
> Meteorol Soc 106:865-872
>
> Painter HE (1981) The shade ring correction factor for diffuse irradiance
> measurements. Solar Energy 26:361-363
>
> Regards
>
> Axel
>
>
> On 10/04/14 01:29, Christoph Reinhart wrote:
>
>> Hi Kyle,
>>
>> Your approach is valid. Depending on what your plan to do with the data,
>> you can also use just global horizontal irradiance and use the Reindl
>> (or another separation model) to model direct and diffuse components. I
>> have used Reindl extensively in the past with satisfactory results. For
>> validation work using two sensors is of course preferable. You can use
>> the gen_reindl.exe command in Daysim to convert a time series of
>>
>> month day hour global-irradiance
>>
>> into a Daysim weather file.
>>
>> Best,
>>
>> Christoph
>>
>> *From:*Kyle Konis [mailto:kskonis at gmail.com]
>> *Sent:* Wednesday, April 9, 2014 8:08 PM
>> *To:* Radiance general discussion
>> *Subject:* [Radiance-general] Experience implementing gendaylit with
>>
>> physical inputs (-G: direct - horizontal irradiance and diffuse -
>> horizontal irradiance)
>>
>> I am curious if anyone has experience to share regarding the generation
>> of skies with gendaylit using physical sensor data as input.
>>
>> I would like to monitor sky conditions at a building rooftop site and
>> plan to collect direct - horizontal irradiance and diffuse - horizontal
>> irradiance using Licor pyranometers.
>>
>> Both sensors will be oriented horizontally. The first will be unshaded
>> and record global horizontal irradiance.
>>
>> The second will have a shadow band applied and will serve to record
>> diffuse horizontal irradiance.
>>
>> I will then subtract the diffuse-horizontal contribution from the global
>> horizontal value to obtain an estimate of direct-horizontal irradiance.
>>
>> I wanted to confirm that this is an appropriate approach, as well as to
>> see if anyone has an alternative (better) idea, that does not involve a
>> pyrheliometer.
>>
>> Best,
>>
>> -Kyle
>>
>> -----------------------------------------------
>>
>> Kyle Konis, AIA, Ph.D
>> Assistant Professor
>> School of Architecture, WAH 204
>> University of Southern California
>> Los Angeles, CA 90089-0291
>> http://arch.usc.edu/faculty/kkonis
>> -----------------------------------------------
>>
>>
>>
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>>
>
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