Some weather files don't work

Dear team,

I've been running IPH Linear (steam) model on SAM version 2018.11.11 and I found many weather files in Texas would result in the error message like below. (Other model inputs are defaulted as in the software)

"exec fail(linear_fresnel_dsg_iph): solver_cr_to_pc_to_cr received exception from mono equation solver
Simulation linear_fresnel_dsg_iph failed."
(Using "USA TX Austin Mueller Municipal AP [ut](TMY3).csv" from NSRDB, attached)
or 

"exec fail(linear_fresnel_dsg_iph): C_csp_lf_dsg_collector_receiver::off - freeze protection failed to converge
Simulation linear_fresnel_dsg_iph failed."
(Using "USA TX Dallas-fort Worth Intl AP(TMY3).csv" from NSRDB)

I don't encounter this problem in version 2020.2.29, but I've been implementing the previous version in my project, so I'm trying to figure out why the weather file doesn't work or if there's a model update between the versions. 

Thanks a lot in advance.
Zhuoran

Hi Zhuoran,

Please try using the Solar Resource File Converter macro to convert the file from the EPW format to the SAM CSV format and let me know if you still have trouble.

To find the macro, click Macros under the Simulate button.

Best regards,
Paul.

Thanks for the quick response! 

The weather file I downloaded is already in CSV format so I couldn't run the Macro. I could run the model with weather files in other states but there are some would trigger error in Texas. I attached one of them in the post.

I also checked the headers in the csv files, but they seems all good.

Best,
Zhuoran

Dear Paul,

May I follow up to ask where I can check the technical model differences between Version 2018.11 and Version 2020.2? Thanks!

Best,
Zhuoran

Hi Zuoran,

The release notes has high-level descriptions of changes in each version. You can find it by clicking the link in the SAM Help window, or by clicking the button on the SAM website Downloads page:

sam.nrel.gov/download

For a more detailed exploration of the source code, you can explore the histories of files on GitHub.com:

github.com/NREL/ssc/tree/develop/ssc

For example:

github.com/NREL/ssc/commits/develop/ssc/cmod_iph_linear_fresnel_dsg.cpp

Best regards,
Paul.