Ag-Cu Bimetallic Nanoparticle Enhanced Phase Change Materials for Concentrated Solar Power Thermal Storage

This work explores the use of silver–copper (Ag–Cu) bimetallic nanoparticles to improve paraffin-based phase change materials (PCMs) for thermal energy storage (TES) in concentrated solar power (CSP) systems.Ag–Cu nanoparticleswere synthesized via chemical reduction, producing uniformly distributed particles with confirmed bimetallic nature. Thermal conductivity analysis, TGA, and DSC were used to create and characterize the nano-enhanced PCMs (NEPCMs). The results demonstrated that after 50 thermal cycles, the addition of 2 weight percent Ag–Cu nanoparticles maintained high latent heat retention (>97%) while improving thermal conductivity by 46.1% and melting time by 27.9%. With the onset decomposition temperature rising from 213.4 °C to 229.7 °C, thermal stability was also improved. NEPCM modules outperformed pure paraffin in a lab-scale CSP setup, achieving higher core temperatures 80.7 °C compared to pure paraffin 73.5°C. The observed enhancements are attributed to the uniform dispersion of Ag–Cu nanoparticles and their high intrinsic thermal conductivity, which facilitates efficient heat transfer and delays thermal degradation. A techno-economic analysis, system-level cost reductions and efficiency enhancements could lower the levelized cost of storage (LCOS) by 5–7%, despite the additional cost of nanoparticles. These results support Ag–Cu NEPCMs' potential as long-lasting and scalable options for next-generation TES applications in CSP systems.