Single fix yearly annual average DNI value in weather file

Dear SAM staff,

I have opened a new solar tower (single owner) project, then I have done the exercise to upload a .csv weather file from an invented location with, instead of 8760 lines with different DNI values, I uploaded a file with a single line with one annual average DNI value, a given wind speed, a given temperature, etc. I wanted to check if SAM was able to compare (doing several simulations) the parameters of the solar tower plant (all fixed: capacity, storage, wind speed, temperature, etc) but varying the DNI to see how a single parameter such as the DNI affects other parameter such as the capacity factor. When I did the first run, howerver, I received the following message 'Simulation failed':

check fail: reason could not parse default value in required_if spec (), with '?=7.5' for: land_max
Simulation tcsmolten_salt failed.
SSC requires input 'hourly_energy', but was not found in the SAM UI or from previous simulations
check fail: reason could not parse default value in required_if spec (), with '?=0.0' for: system_heat_rate
Simulation singleowner failed.

Therefore, I wonder if I cannot do the exercise of keeping all the parameters fixed but vary only the DNI to see how the power plant behaves.

Thank you.

Thanks Paul for the reply. Therefore, could you confirm please that if I wait one week till the new version of SAM is released, I could upload a weather file (.csv) with a single line (as annual average) with a single value of DNI, wind speed, temperature, etc. instead of 8760 lines?

Hi Tom,

No. SAM requires an hourly or subhourly weather file (with at least 8,760 rows of data for each data element) to run simulations. It cannot run hourly (or subhourly) simulations with only annual average data as input.

Best regards,
Paul.