Use measured incident radiation on the surface

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FLECAR
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Use measured incident radiation on the surface

Post by FLECAR » Wed Feb 12, 2020 9:24 am -1100

Hello,

I will study a façade where I can install experimentally a pyranometer on the façade surface (incident radiation on the surface). Would it be a better, worst or equivalent solution than measure the horizontal global and diffuse radiation if I want to compare my results with the equivalent WUFI model ?

Thanks

Thomas
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Re: Use measured incident radiation on the surface

Post by Thomas » Wed Feb 12, 2020 10:18 am -1100

Hi FLECAR,

if you install a pyranometer on the surface under investigation, you will need only one pyranometer instead of two for global and diffuse radiation (unless you wish to investigate more than one facade). Converting from global and diffuse measurements to an inclined surface always involves some model assumptions and is never as accurate as a direct measurement. The pyranometer on the facade will also measure local peculiarities which could not easily be taken into account in a conversion calculation, such as occasional shading of the facade by local objects (trees, houses), or the radiation reflected by the ground, with possibly variable reflectivity.

On the other hand, these measurements can only be used for this purpose and for this specific facade. Measuring global and diffuse radiation on a horizontal surface allows you to convert the data for any number of surfaces with any orientations and inclinations.

Regards,
Thomas

FLECAR
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Joined: Fri Jan 03, 2020 6:03 am -1100

Re: Use measured incident radiation on the surface

Post by FLECAR » Thu Feb 20, 2020 1:32 am -1100

Thank you very much Thomas!

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