Belpe Load Profile Estimator

Hi,

I would like to use the Belpe module of PySAM to independently compute a load profile based on the inputs of the Belpe module (Monthly_util, occupants, floor_area, ...) but without computing a complete PV system. For example, would it be possible to do this in python:

Obviously, this code does not work as the variable 'belpe_model.LoadProfileEstimator.load' is an input and not an output of the model. So is there a way to get the resulting load without computing a complete PV system ?

Thanks for your help

Hi Antoine,

You should be able to run the BELPE module in PySAM as a standalone module. See the module's documentation for a list of required inputs: nrel-pysam.readthedocs.io/en/master/modules/Belpe.html

If you have the inputs set up in SAM, you should be able to use the technique described here to export the SAM inputs to JSON. You can then read the relevant inputs from the JSON file, or if you want, edit the JSON file to remove all of the inputs except the BELPE inputs.

Best regards,
Paul.

Hi Paul,

Thanks for your reply. I figured out it was my solar resource file which was giving errors for the belpe model which was computing a load profile full of NaN. 

The solar resource file was actually an EPW file from the PVGIS Online Tool ( re.jrc.ec.europa.eu/pvg_tools/en/ ). It is the one I used to simulate a complete PVBattery system where everything went fine, but it apparently does not work on the Belpe Model. Do you know which information are missing in the EPW file of PVGIS that makes it obsolete for the Belpe model?

Thank you

Hi Antoine,

I suspect that the EPW file from PVGIS does not contain GHI data. SAM's PV models will run with a weather file that contains only DNI and DHI data, but the BELPE model requires GHI data. Here is the line in the BELPE source code that assigns the GHI data:

github.com/NREL/ssc/blob/cde780767d04d9e4bc81563f4c2a7783a6088138/ssc/cmod_belpe.cpp#L212

You could use the PVWatts model in SAM, or Pvwattsv8 module in PySAM to calculate the GHI data by setting the tilt angle ('tilt' in PySAM) to zero and then using the "Plane of array irradiance" output ('poa' in PySAM) in your weather file with the column heading "GHI".

EPW files are tricky to edit, so you could use SAM's "Weather File Converter" macro to convert the EPW file to the SAM CSV format, and then add the GHI column. Here is a link to the description of the SAM CSV format in SAM's Help system:

samrepo.nrelcloud.org/help/weather_format_sam_csv_solar.htm

Best regards,
Paul.