The power cycle models for the SAM CSP technologies (excluding the Empirical Trough) assume a steam Rankine system.
However, because the cycle efficiency is an input, if the relative off-design behavior of the organic cycle is similar to the relative behavior of the steam cycle, you might be able to model the organic cycle by adjusting the design-point cycle efficiency to the desired value.
For more information on how the power cycle is modeled, including relative off-design performance, see M Wagner's "Methodology for Constructing
Reduced-Order Power Block Performance Models for CSP Applications" (
www.nrel.gov/docs/fy11osti/49370.pdf
).
If the off-design behavior described in this paper does not match the organic cycle and the cycle often operates away from the design point, we would recommend using the empirical trough model instead of the physical trough model. You can specify coefficients in the empirical model to approximate the performance of organic Rankine cycles. You could use the coefficients for the APS Ormat 1MWe 300C option in the Power Cycle library as a starting point.
Best regards,
Paul.
