HB UTCI component fails with custom EPW

[jroberts]

Hi all,

When running HB UTCI, it runs fine when I use a weather file downloaded straight from the E+ website, but when I use a dragonfly component so make some modifications to this epw, I get the following error:

Attached is the DF modified epw:
Banded_to_EPW.epw (1.9 MB)

Does anyone have any suggestions?

Thanks!!

[chris]

It seems likely that you are experiencing this bug that @mikkel just fixed here?

NaN Results When Analysis Period is over a month

Hi @homan95, Thank you for running additional tests. In short, the recipe saves the various NumPy files using the lowest possible data type without compromising accuracy, in order to reduce disk space usage. In your case, the issue occurred during the UTCI matrix calculation. The air temperature file used in that step was saved as float16, which led to overflow issues later in the NumPy calculations. I suspect the annual/monthly analysis worked because the same file was saved as float32 at th…

Particularly because your component versions are older for 1.9 instead of 1.0. Try installing LBT 1.10 and then running the Versioner to see if that solves your problem.

[jroberts]

Hi @chris,

I updated to LBT 1.10.0 (and updated OpenStudio and Radiance), but I’m still having the same issue.

I’ve made a copy of my gh file with the model and epw internalised here:
2026-03-02_Internalised.gh (38.7 KB)

Thank you!
Joe

[chris]

I did not update the installer.gh on Food4Rhino with the fix that @mikkel pushed. So you now need to run the LB Versioner and restart Rhino. After that, everything should work.

[jroberts]

Hi @chris,

I’ve run LB Versioner again, restarted Rhino, restarted my pc and still it’s not working. I’ve also navigated to the utci.py script on my pc which has the fix from @mikkel, so I’m pretty sure I have the latest version installed.

I’ve attached the log file.
logs.log (426.7 KB)

I’ve attached my gh file with internalised data - the other one wasn’t working. (The relevant part is on the right hand side, everything else is building the model based on an xml export from a different tool)
2026-03-03_Internalised.gh (195.2 KB)

Thanks again.
Joe

[chris]

Thanks, @jroberts .

I can see from the logs you uploaded that the issue is not the one that Mikkel already solved bus a different one. The EnergyPlus simulation within the comfort map recipe is failing with the following herror:

2026-03-03 12:06:07 INFO: ** Severe  ** CalcHeatBalanceInsideSurf: The temperature of -282845.13 C for zone="ROOM_4_343768CC", for surface="ROOM_4_343768CC..FACE87"
2026-03-03 12:06:07 INFO: **   ~~~   ** ..is very far out of bounds during warmup. This may be an indication of a malformed zone.
2026-03-03 12:06:07 INFO: **   ~~~   **  During Warmup, Environment=RUN PERIOD 1, at Simulation time=08/31 18:40 - 18:50
2026-03-03 12:06:07 INFO: **  Fatal  ** Program terminates due to preceding condition.

Your Grasshopper definition has several plugins in it that I do not have:

It also depends on some extra CVS here that I do not have

So I cannot run it but I would check to make sure you don’t have a lot of no-mass constructions in this model. The lack of thermal mass and high insulation can sometimes cause E+ surface temperatures to reach unreasonably high values.

[jroberts]

Hi @chris,

Apologies, I thought I had internalised everything. But I think I’ve figured it out - the epw I created used a repeating day each month, and I was looking at the 31st August, perhaps right before a big massive change into september, which might have caused the instability in the error. I’ve re-run on the 15th August and all is well.

Thanks again,
Joe