TRY file solar radiation error?

Michael Hurd · Post by **Michael Hurd** » Wed Aug 03, 2011 4:38 am -1100

When running a calculation recently using a TRY file that I created I noticed something that has me concerned - when I clicked the "analyze" button under the "climate analysis" header the "Sun Radiation Sum" graph is solid red instead of showing different gradation of color/radiation. Is this related to using the "TRY" format or does it possibly indicate an error in the solar data that I used for this file? I'd be interested in knowing your thoughts on this one!

Thomas · Post by **Thomas** » Wed Aug 03, 2011 1:34 pm -1100

Michael Hurd wrote:the "Sun Radiation Sum" graph is solid red instead of showing different gradation of color/radiation. Is this related to using the "TRY" format or does it possibly indicate an error in the solar data that I used for this file?

That graph should work for TRY files just as it does for other formats. There seems to be a problem with the radiation data which prevents WUFI from correctly computing the amount of radiation hitting surfaces with different orientations and inclinations (i.e. the resulting amount is the same for all orientations and inclinations, which shouldn't be).

One of the radiation columns in a TRY file is the direct radiation as incident on a horizontal surface, the other column is the diffuse radiation on a horizontal surface.

Regards,
Thomas

Michael Hurd · Post by **Michael Hurd** » Thu Aug 04, 2011 3:13 am -1100

Thomas, thanks for the quick response! So, are you suggesting that perhaps I have these columns swapped within the try file or perhaps I copied the incorrect column from the NOAA weather CD we have? Or is more likely that the data itself has some issue? Probably all questions you can't answer without the file but I thought I'd ask anyway. Seems like in the past I've had some issues with the NOAA data having all the information that WUFI needs.

Thomas · Post by **Thomas** » Fri Aug 05, 2011 1:08 am -1100

It is difficult to guess what the problem might be. Maybe a wrong column has been copied, maybe the radiation data are in other units that need to be converted first, etc...

It may also be conceivable that the radiation data are okay, but the geographical coordinates or the time zone are wrong. WUFI then cannot correctly compute the amounts of irradiation onto surfaces with different orientations and inclinations.

When you hover the cursor over the central point of the radiation rose, a help tip will pop up which tells you the annual energy incident on a horizontal surface (for Holzkirchen, this is around 1200 kWh/(m2 a)). Maybe you can compare that with radiation maps to see how far off you are.

What is somewhat irritating is the fact that the radiation rose does not indicate zero radiation (it would be black then), but some non-zero value which is, however, not properly distributed over the various orientations and inclinations. Is this data for an arctic location which has lots of midnight sun in summer and no sun in winter? In that case the radiation rose may look very flat, with little variation over its whole area.

Regards,
Thomas

Michael Hurd · Post by **Michael Hurd** » Fri Aug 05, 2011 2:50 am -1100

Thomas, the data is for a location in Texas, so no it would not be similar to an arctic condition. I compared the rose to other locations in Texas and did not find a rose that was solid red like this one. I will check my columns and my units, hopefully it is one of those items. As always, thanks for all your help! If you have any additional ideas let me know.

WUFI