Identifying SSC variables in PySAM or the SDK tools

  • pgilman
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04 Jun 2020 17:12 - 05 Jun 2020 22:03 #8277 by pgilman
Hi all,

I often get questions about what a particular SSC variable is. For example, someone recently asked about the following variables:

spe_a
spe_b
spe_dT

There are a few ways to figure out what these variables are. Keep in mind that this code was originally written for a  desktop application with a user interface, so the variable names and descriptions are not always as clear as they might be.

This example happens to be for the PV model's "Simple Efficiency Module Model", but you can use the same techniques to identify variables for any other performance or financial model.

The first technique is to use the SAM desktop application's user interface. In this case, all variables preceded by “spe” are inputs for the “Simple Efficiency Module Model” option on SAM's Module input page, and you can tell a lot about the variables by looking at how they are presented there:



The spe_a, spe_b, and spe_dT variables are parameters for the model’s cell temperature model:



SAM's inputs browser (File, Inputs browser) displays a searchable table of all input variables in a SAM project showing both the variable's SSC name and, in most cases, the label that appears in the user interface.

The code generator (Case menu, Generate code) generates text files of input variables and values in Python, C, MATLAB, etc. or as JSON match those in SAM as described at sam.nrel.gov/software-development-kit-sdk.html .

If you are using PySAM, you can find variable descriptions in the PySAM documentation . The variables are grouped using a group name based on the SAM user interface. For example, the simple efficiency module model variables belong to the SimpleEfficiencyModuleModel group, and are described at nrel-pysam.readthedocs.io/en/master/modules/Pvsamv1.html?#PySAM.Pvsamv1.Pvsamv1.SimpleEfficiencyModuleModel.

Finally, the SDKtool is a desktop application that comes with SAM and also a good way to explore the SSC compute modules. Find out more about SDKtool at sam.nrel.gov/software-development-kit-sdk.html .

Best regards,
Paul.
Last edit: 05 Jun 2020 22:03 by pgilman.

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  • cherrysweetooth
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02 Jun 2023 23:44 #12198 by cherrysweetooth
Replied by cherrysweetooth on topic Identifying SSC variables in PySAM or the SDK tools
When encountering unfamiliar variables like "spe_a," "spe_b," and "spe_dT," it's understandable to feel uncertain about their meaning and purpose. In this particular case, these variables are associated with the "Simple Efficiency Module Model" within the PV model.To identify the meaning and significance of these variables, there are a few helpful techniques you can employ. Firstly, you can utilize the user interface of the SAM (System Advisor Model) desktop application, which provides insights into variable definitions and descriptions. In SAM's Module input page, you will find all variables associated with the "Simple Efficiency Module Model" prefixed with "spe." Analyzing their presentation within the user interface can offer valuable clues regarding their purpose and usage.

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