Hi all
I'm generating a climate file from Meteonorm and would like to check the appropriate inputs to use.
The Modifications tab in Meteonorm allows you to input the Azimuth and Inclination for your location.
I am unsure whether I should be adjusting this as WUFI also allows you to select these.
I've noticed it makes a difference to the results. Could somebody tell me what is the best approach please?
Thank you
David.
Meteonorm Inputs
Meteonorm Inputs
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Re: Meteonorm Inputs
Hi David,
solar radiation is a directional quantity, its effect on the receiving surface depends on the angle between the incoming radiation and the receiving surface. Meteorological files usually contain the solar radiation measured on a horizontal receiving surface. For a simulation of a non-horizontal surface the data from the file have to be converted to be applicable to this surface, depending on the inclination and orientation of the surface.
WUFI performs this conversion automatically during the simulation. It expects the radiation data in the climate file to refer to a horizontal plane and for each time step computes the radiation incident on the simulated surface. It uses a relatively simple conversion model which is described in the Q&A section of the help file.
WUFI also provides the option to use "ready-made" radiation data which have been pre-computed for a given surface or measured on the surface to be simulated. A measurement made on the surface itself (if the surface to be investigated actually exists) provides the most accurate data, taking into account all the details of the specific environment such as shading by a particular tree or reflections from a neighbouring facade.
If no measurements made on the surface are available, arbitrarily sophisticated models may be used to pre-compute the radiation incident on the simulated surface.
In these cases, the column containing the resulting radiation in a WAC file is labelled "ISM" (M as in Measured) to tell WUFI that these radiation date are to be used without further conversion or modification. Any global and diffuse radiation (ISGH, ISD) in such a file will be ignored.
The advantage of using "ISM" data is that all peculiarities of the investigated location can be taken into account. The disadvantage is that these data can only be used for this specific location and for a surface with this specific inclination and orientation. The advantage of "normal" files with global and diffuse radiation for conversion by WUFI is that they can be used for all possible inclinations and orientations.
MeteoNorm offers the option to compute radiation data as incident on a surface whose inclination and orientation is specified by the user. According to the documentation MeteoNorm uses more elaborate models than WUFI, so it might be preferable to have the directional conversion done by MeteoNorm.
However, I created two WAC files in MeteoNorm with different settings for the "plane orientation" and got two identical files. The WAC format as written by MeteoNorm is specified to contain the columns ISGH and ISD (both referring to a horizontal plane) and apparently MeteoNorm does not override this specification. So you must WUFI let do the conversion.
If you can determine which of the other MeteoNorm file formats contains plane-specific radiation data, you could in principle extract the data from there and write them as an ISM column into the WAC file. But the benefit may probably not be worth the effort.
Regards,
Thomas
solar radiation is a directional quantity, its effect on the receiving surface depends on the angle between the incoming radiation and the receiving surface. Meteorological files usually contain the solar radiation measured on a horizontal receiving surface. For a simulation of a non-horizontal surface the data from the file have to be converted to be applicable to this surface, depending on the inclination and orientation of the surface.
WUFI performs this conversion automatically during the simulation. It expects the radiation data in the climate file to refer to a horizontal plane and for each time step computes the radiation incident on the simulated surface. It uses a relatively simple conversion model which is described in the Q&A section of the help file.
WUFI also provides the option to use "ready-made" radiation data which have been pre-computed for a given surface or measured on the surface to be simulated. A measurement made on the surface itself (if the surface to be investigated actually exists) provides the most accurate data, taking into account all the details of the specific environment such as shading by a particular tree or reflections from a neighbouring facade.
If no measurements made on the surface are available, arbitrarily sophisticated models may be used to pre-compute the radiation incident on the simulated surface.
In these cases, the column containing the resulting radiation in a WAC file is labelled "ISM" (M as in Measured) to tell WUFI that these radiation date are to be used without further conversion or modification. Any global and diffuse radiation (ISGH, ISD) in such a file will be ignored.
The advantage of using "ISM" data is that all peculiarities of the investigated location can be taken into account. The disadvantage is that these data can only be used for this specific location and for a surface with this specific inclination and orientation. The advantage of "normal" files with global and diffuse radiation for conversion by WUFI is that they can be used for all possible inclinations and orientations.
MeteoNorm offers the option to compute radiation data as incident on a surface whose inclination and orientation is specified by the user. According to the documentation MeteoNorm uses more elaborate models than WUFI, so it might be preferable to have the directional conversion done by MeteoNorm.
However, I created two WAC files in MeteoNorm with different settings for the "plane orientation" and got two identical files. The WAC format as written by MeteoNorm is specified to contain the columns ISGH and ISD (both referring to a horizontal plane) and apparently MeteoNorm does not override this specification. So you must WUFI let do the conversion.
If you can determine which of the other MeteoNorm file formats contains plane-specific radiation data, you could in principle extract the data from there and write them as an ISM column into the WAC file. But the benefit may probably not be worth the effort.
Regards,
Thomas
Re: Meteonorm Inputs
Hi Thomas
Thank you for this in depth response and great explanation.
David.
Thank you for this in depth response and great explanation.
David.