Abstract

This research explores the combination of fins into thermosyphon solar collectors to enhance energy efficiency. The storage system includes a finned container filled with nanomaterial (a blend of Al2O3 nanoparticles and paraffin (RT30)), while the fluid circulating within the tube consists of a homogeneous mixture of copper nanoparticles and water. Unsteady laminar flow within a three-dimensional domain, incorporating gravitational forces, has been modeled. The numerical approach has undergone rigorous validation, demonstrating strong agreement with both experimental and numerical data. Effects of fin installation and nano-powder dispersion have been investigated across various scenarios. At t=60 minutes, the liquid fraction (LF) is approximately 2.08 times higher in the system with fins compared to the simple case. LF progressively increases over time, reaching a value 3.1 times higher at t=60 minutes compared to t=30 minutes. The temperature of the nanofluid in the tank rises over time. Despite the enhanced nanofluid temperature in the tube due to fin presence, a decrease occurs within the domain due to accelerated melting rate in the container. Incorporation of nanoparticles into paraffin shows an improvement in LF by approximately 11.66% in the presence of fins.