Parameter descriptions for retrieve_sam

[toddkarin]

The pvlib.pvsystem.retrieve_sam function pulls information on modules, but the different keys don't have descriptions. For example, I don't know what 'A_c' means in the CECMod database. Can these various fields be described?

[toddkarin]

By sleuthing into the CEC database 'A_c' seems to be the module area in m^2, but it would still be nice to have this documented in PVLIB.

For example Beta_oc is in %/C in the CEC module database, but in V/C when returned from pvlib.pvsystem.retrieve_sam.

[toddkarin]

@cwhanse Would this be a good opportunity for incorporating pv-terms in order to describe the various parameters? It may also require a relabeling of the CEC values.

[cwhanse]

Yes, it is timely to consider changing terms and improving the documentation. There's a discussion of refactoring the current retrieve_sam into the pvlib.iotools module. With new functions in iotools we would deprecate the current retrieve_sam for a while, to make transition easier.