Heat transfer modeling of a parabolic trough solar collector with working fluid of Fe₃O₄ and CuO/Therminol 66 nanofluids under magnetic field

Solar energy is among the cleanest and most adaptable compared to other renewable energy sources. The major challenge is how to get this energy in efficient way to make it available for industrial applications such as electricity generation. One of the most efficient techniques to harvest solar energy and transform it into electrical energy is parabolic trough solar collector (PTSC), which is a type of concentrating solar power generation systems. This system operates by concentrating solar irradiance onto a tubular receiver in which this centralized energy is absorbed by a heat transfer fluid and transported to the power cycle. Improving the performance of the PTSC can enhance efficiency as well as power generation of a PTS power plant. Hence, this issue has been considered as one of the major challenges for scholars in this field. One promising solution is finding more efficient heat transfer working fluids. Another suggestion is proposing a different geometry for the receiver. In the current research, ferrofluids due to their heat transfer characteristics are proposed as working fluid for a PTSC. Fe₃O₄/Therminol 66 and CuO/Therminol 66 nanofluids are examined under external magnetic field for this target. Besides, to improve the heat transfer characteristics of the collector, the receiver is designed with internal fins. This work is carried out using computational fluid dynamics (CFD). The assessments are done by considering the different nanoparticle sizes on the friction factor, thermal efficiency, performance evaluation criteria (PEC) and convective heat transfer. The results depict that reducing the particle size and enhancing the nanoparticles volume fraction increase the convective heat transfer coefficient, Nusselt number, PEC and the collector efficiency. In addition, the collector efficiency rises in the attendance of the magnetic field and maximum efficiency of the collector was obtained for 4% Fe₃O₄/Therminol 66 working fluid.