Radiation results Ladybug vs. Honeybee+

[OlivierDambron]

hi @mostapha,

I’ve run a simple solar radiation analysis both through Ladybug and Honeybee+ as following.

Both simulation return results that are 12% off. Given that the HB+ radiation analysis runs through DC recipe on radiance, I understand that the direct sun contribution is calculated based on the analema and not the sky patches as it is the case through Ladybug.
I’ve tried in vain to increase the sky density using a Reinhart sky hoping that the results would converge slightly better.

Would you have a better way to explain the difference in the radiation results?

Also, would it be possible to confirm whether the results out of the HB+ cumulative-results-component are to be divided by 1000 to obtain kWh/m2 ?

[OlivierDambron]

well spoke to fast and found the answer here:

Why LadyBug radiationAnalysis and energyplus differ in results?

Mostafa, I’m not sure if i understood your question, but i’ll try to answer what i did. Ladybug considers ONLY direct beam radiation. It doesn’t account for the reflected/diffuse. For that you need to use Honeybee (Radiance radiation analysis) Hope this is what you asked. -A.

“Ladybug does consider both direct-light and sky-light from the sky. It doesn’t calculate the reflections though.”

Kind regards,
Olivier

[mostapha]

Also this might help:

Radiation analysis horizontal grid

Hi everyone, I tried to run some tests to calculate the solar radiation on a horizontal plane with different components (PIT, RAD and DC). I used San Francisco climate file. I found some weird results: As you can see in the figure attached for all the methods the radiation value is not uniform all over the plane. Using RAD component the value doesn’t “match” the global horizontal radiation value from the EPW. Different results between RAD e DC simulations. DC results are closer to the climate…