I am simulating a 100 MW CSP Plant with 10 hours storage, and I am trying to assess and interpret the results by SAM.
To that end, I export the hourly data to Excel and plot pairs of values to see their correlation.
For instance, if I plot the Thermal Power into the Storage, it should be almost proportional to the HTF mass flow rate into storage, the proportionality constant being HTF_Specific_Heat x HTF_Delta_T_across_HEX.
Then I loop through various pairs of variables, which I understand should be linear correlated, and have found several results that astonish me. The Plots can be found in the attachment with some screenshots of the input data to SAM, as well as some of my remarks and annotations.
The one that baffles me the most is when I plot the System Power Generated (MWe) versus the Cycle Thermal Power Input (MWt).
Considering that the Rankine Cycle has an efficiency of around 40%, to produce 100 MWe, we should have around 250 MWt in the Cycle.
Well, I get exactly that, but not ONLY THAT! I get a clear linear correlation at half the power. That is, for 250 MWt, the Generated power amounts only 50 MWe approx. This means, that the system is considering a Rankine efficiency of just half (20%).
I would appreciate some light on these questions.