Numerical investigation of thermal energy storage in solar systems with hybrid nanoparticles and tree-shaped fin designs

The present study develops the new fin geometry with the objective of boosting the effectiveness of solar energy storage applications. A triplex-tube structure is utilized, where both the inner and outer fluid channels receive heated fluid from a concentrated solar setup. The phase change material (PCM), paraffin RT60, is augmented with a hybrid nanoparticle mixture of silicon carbide (SiC) and carbon nanotubes (CNTs) at a 0.02 vol fraction to improve its thermal conductivity. The numerical simulation is performed employing the FLUENT software and validated against well-established benchmarks in melting studies. To evaluate the influence of hybrid nanoparticle dispersion and fin configurations on thermal performance, four main cases are analyzed. Two novel tree-shaped fin designs—discrete and continuous—are introduced to boost heat transfer and accelerate phase change. The outputs showed that integrating hybrid nanoparticles into paraffin decreases melting and freezing durations by approximately 8.18 % and 13.85 %, respectively. However, the continuous tree-shaped fin configuration proves to be the most efficient, significantly improving energy storage performance. Relative to the base case, which excludes fins and nanoparticle enhancements, this setup reduces melting time by 52.59 % and solidification time by 80.91 %, demonstrating a remarkable enhancement in heat transfer efficiency.