Dear Susan,
SAM's molten salt power tower model includes a thermocline model for the thermal energy storage system. The thermocline option is not available for the other CSP models. As far as I know, the baseline systems described in the documents on the
System Cost Data
page do not use thermocline storage.
Here is a
link
to search results from the NREL Publications database on the keyword 'thermocline' that may be helpful.
Best regards,
Paul.