Solar radiation and incident angle based optimum system configuration selection for parabolic trough solar collectors: Dynamical performance, economic and environmental analysis

This study investigates the thermodynamic, economic, and environmental impacts of variations in Direct Normal Irradiance (DNI) and incident angle in parabolic-trough collectors, with area cosine losses (cos θ) explicitly included, using a full year of meteorological data. Six sub-configurations across the Kalina (KC), Steam Rankine (SRC), and Organic Rankine (ORC) cycles were evaluated. Results show that performance generally increases with higher DNI; however, larger incident angles can significantly reduce collector efficiency and system output, so maximum performance does not necessarily coincide with maximum DNI. For example, although the maximum DNI recorded was 840.8 W/m2 at an incident angle of 20.1°, the highest net power and CO2 reduction occurred at 829.8 W/m2 with an incident angle of 1.71°. Under this condition, the ORC-HEX (R123) produced 67.8 MW of net power and 41.45 t/h of CO2 reduction. The Kalina cycle delivered the most favorable economic results, with an LCOE of 0.0628 $/kWh and a payback period of 6.03 years. A comprehensive 4E analysis underscores the importance of accounting for solar-geometry effects—particularly incident angle—in performance evaluations. The study concludes that optimizing on DNI alone can be misleading; accurate assessment requires simultaneous consideration of both DNI and incident angle in real-world solar-thermal applications.