Enhanced performance of parabolic solar trough collectors: integration of hybrid nanofluids, spinning inserts, and advanced fluid dynamics
摘要
With rising global energy demands and increasing environmental concerns, solar thermal energy systems have gained attention as a clean and renewable energy source. Among them, parabolic trough thermal performance and efficiency of PTCs is essential for broader adoption and greater energy output. Conventional PTC systems often suffer from thermal inefficiencies due to limited convective heat transfer and suboptimal working fluid properties. These shortcomings result in lower thermal efficiency, higher entropy generation, and restricted system stability, especially under varying flow and temperature conditions. There is a need to improve heat transfer mechanisms and reduce thermal losses to make PTCs more effective. This study introduces a modified PTC using a concentric tube configuration, hybrid nanofluids, and flow-enhancing techniques. The outer tube contains a hybrid nanofluid (Al₂O₃, CuO, and GO) at 1% volume in a 50:50 water–Syltherm 800 mixture. The inner tube uses pure water, pure Syltherm 800, or a 50:50 blend. ANSYS Fluent 2023 simulates fluid dynamics and heat transfer, while Tonatiuh 2.2.4 models solar radiation. Triangular fins on the outer tube and spinning inserts (up to 15 rad s−1) in the inner tube enhance thermal performance across flow rates of 0.15–0.6 kg s−1. At 0.6 kg s−1, the outer and inner tubes achieve peak thermal efficiencies of 74.73% and 66.02%, with Nusselt numbers of 810 and 583.38. Entropy generation decreases by up to 22.13% and 18.22%, confirming notable performance improvements.