Design and steady-state simulation of a CSP-ORC power plant using an open-source co-simulation framework combining SAM and DWSIM

Numerical modeling and simulation are necessary to design and optimize processes that include concentrating solar power (CSP) and industrial chemical processes; however, no co-simulation environment have been used or suggested in the literature for such plants. This paper suggests a promising approach to build a user-friendly simulation framework using open-source tools. DWSIM simulator was leveraged to include SAM CSP model using Python programing language. The included CSP model is enhanced by adding routines to automatize solar field design by estimating solar field surface and making the appropriate choice of solar multiple and thermal storage capacity for a given daily operating period. This approach allows using of DWSIM optimization features (multivariable optimization and sensitivity analysis) and logical operations (specification, recycle, and controller block) for the whole process including the CSP unit. Furthermore, data transfer between both units is automatic and bi-directional which allows iterative calculations. As a result, the proposed method leads to the establish-ment of a homogenous co-simulation platform that includes all models required for the CSP coupled to an organic Rankine cycle (ORC) plant at steady state. CSP-ORC simulation can be run using modular-sequential approach without user interference. The resulting co-simulation platform was successfully used to design a solar-powered ORC for an arid rural settlement in Africa. The optimal design parameters for a 15-hour operating period per day correspond to a direct normal irradiation of 450 W/m2, a temperature change of the heat transfer fluid of 75 degrees C, a solar multiple of 1.4, and 4 h of storage capacity.