Energy optimization of parabolic dish solar concentrator coupled to organic Rankine cycle: Experimental and analytical investigation of cavity receiver design and covering effects

Concentrated solar power (CSP) systems offer a promising solution for sustainable energy, but achieving high and stable efficiency requires careful design optimization. This study evaluated the overall performance of a parabolic dish solar concentrator coupled to an Organic Rankine Cycle (ORC) system through experimental and analytical assessments. The research examined the impact of cavity receiver shape (cylindrical vs. spherical) and the use of a glass cover on thermal efficiency. Additionally, the effectiveness of a cone structure to reduce spillage losses and improve optical efficiency was explored. Testing showed a significant improvement in system performance, with an increase from 75 % for the open cavity to 90 % for the sealed cavity equipped with the cone structure (15 % increase). This highlights the importance of receiver design in reducing heat loss. To further optimize the system, a numerical model was developed and validated against experimental measurements. The simulation demonstrated that the overall system performance is significantly influenced by the water outlet temperature from the cavity receiver and the pressure drop within it. The model suggests that overall performance could be enhanced from 4.6 % to higher than 6 % by optimizing factors like water mass flow rate, cavity tube diameter, and the selection of a more suitable ORC working fluid (e.g., R245fa instead of R134a).