THERMAL PERFORMANCE OF SILVER NANOPARTICLE-ENHANCED NANOFLUIDS IN HEAT PIPE SYSTEMS: THE ROLE OF SURFACE MODIFICATIONS

This study evaluates silver nanoparticle-based nanofluids' thermal performance and stability with different surface modifications in a heat pipe system. The nanoparticles were stabilized using polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), lipoic acid, branched polyethylenimine (BPEI), and citrate, with deionized water as the baseline fluid. The nanofluids were prepared at a 0.2% weight concentration, and their stability was assessed through zeta potential measurements, while their thermal performance was evaluated based on thermal conductivity and heat transfer efficiency. Results indicated that BPEI-stabilized nanofluids exhibited the highest thermal conductivity, ranging from 0.72 W/m·K at 20°C to 0.82 W/m·K at 80°C. Stability analysis revealed that BPEI also provided the highest negative zeta potential, enhancing nanoparticle dispersion over 30 days. The study concluded that BPEI-stabilized nanofluids offer superior thermal performance and stability, making them ideal for heat transfer applications. The findings contribute to optimizing nanofluid formulations for industrial thermal systems.