TMY/TMYx EPW weather data with high East-West deviation using GenCumulativeSky.exe

[vhoang]

Hi everyone,

We have an issue with the Honeybee_Generate Cumulative Sky component using different TMY-Datasets.

We tried with 2 different sources of EPW files, including PV-GIS and climate.onebuilding.org and both results in high difference between East/West irradiation already present in *.cal file.

If we use the IWEC EPW from DOE site, the generated sky looks good and the difference between the east-west irradiation seems ok.

So, it seems there is a general issue using GenCumulativeSky.exe TMY/TMYx datasets. Has anyone experienced the same issue and can help me out? Is there a detailed documentation of GenCumulativeSky.exe that we can look into in order to figure out what’s the problem with the calculation?

Attached are the weather files for your reference.
With high East/West deviation: PVGIS TMY EPW
With highEast/West deviation: Onebuilding TMYx
OK: IWEC DOE

Thanks a lot.

[mostapha]

Hi @vhoang! Hope all is well. There is an issue. I remember having this issue with some weather files in Australia too. Try using the gendaymtx -A instead.

[vhoang]

Hi Mostapha,
Thanks for your response, hope you and everyone is doing well also. I’m not doing much analysis any longer but always following you guys, and very happy+impress to see what’s happening with Pollination.

Regarding the problem with TMYx weather data, I tried with ladybug genCumSky which I believe use gendaymtx and the result seems weird also. The bottom row has very little radiation on West side and generally Eastern sky has some bright patches with higher direct radiation.