One doubt about radiation data

Hi all,

i have a doubt about the results of the Ladybug_Radiation_Analysis component: the description of the radiation results says that values are expressed in Wh/m2, but the legend that appears in the Rhino window says kWh/m2…

Values are the same, so where is the problem? Am i missing something?

Attached there is a screenshot of my definition…

Thanks!

Francesco


Hi Francesco,

This is a known bug that I thought we have fixed but apparently it is not fixed yet (https://github.com/mostaphaRoudsari/ladybug/issues/62). Thank you for reporting.

The answer is that it depends on how you generate the sky. If the sky is selected for an HOY then the values will be in wh/m2, otherwise the values are in Kwh/m2. Based on your image and the values I guess that you’re generating an annual sky and so Kwh/m2 is correct.

Mostapha

Thank you Mostapha.

Thank you for posting, Francesco. I think that Mostapha and I each thought that the other was going to fix the issue and neither of us ended up addressing it. Rest assured that it will be taken care of before the stable release that is happening soon.

Francesco,

I am just letting you know that this is now fixed. All of the Ladybug radiation components now use kWh, as do all of the Honeybee energy modeling components. The only place where Wh still appear (in all of the components) is in the import of radiation with the Import EPW component (I figure that we should stay true to the EPW file).

Enjoy!

-Chris

Hi Chris!

Maybe I’ve been sitting at the computer for too long, or does this seem a bit strange?

A mass addition of the radiation results gives the same results as the total radiation output.



The info for each of the outputs says…

“RadiationResults: The amount of radiation in kWh/m2 falling on the input test _geometry at each of the test points.”

"TotalRadiation: The total radiation in kWh falling on the input test _geometry. This is computed through a mass addition of all the kWh/m2 results at each of the test points and then multiplying this by the area of all the the surfaces in the test _geometry."

The upper panel in the image should therefore be displaying the results in kWh/m2 and the lower panel should be displaying the results in kWh… but they give the same result.

Hi Orn,

Is the grid size equal to 1 m2? If not, you are right that I made a typo in the description. Mostapha, are the results in total radiation divided by the area of each grid cell? If not, than an output name of “totalRadiation” might not be so appropriate.

-Chris

Seems to be fixed in the latest version (March 8th). I can’t remeber which grid size I had when I posted the question.

Anyway, it works now. As always, thank you for the quick reply!

Hi Orn and Chris,

totalRadiation is equal to sum of radiationResults for each surface multiplied by the area of the surface. If you want to compare them you need to multiply the number with the area and then add them up.

Mostapha