Impact of coated silver nanoplates on the thermal efficiency of heat pipes under varying operating conditions

Efficient thermal management is crucial in modern industries, driving the search for advanced materials to enhance heat pipe performance. Silver nanoplates, known for their superior thermal conductivity and unique plasmonic properties, were selected as a nanofluid base material in this study. Polyvinylpyrrolidone (PVP) and silica coatings were applied to stabilize these nanoplates and influence their thermal behavior. While prior research demonstrates that nanofluids can enhance heat transfer, the role of silver nanoplates with specific coatings and morphologies in heat pipes remains underexplored. This work aims to quantify the optimization achieved using such engineered nanofluids. Silver nanoplates with controlled morphologies were synthesized to exhibit plasmonic resonance peaks at 660 nm, 800 nm, 980 nm, and 1064 nm. PVP and silica coatings were applied to improve dispersion stability, and the resulting nanofluids were tested in a copper heat pipe under varying filling ratios (60–90 %) and inclination angles (0°–90°). Thermal resistance and heat transfer coefficients were measured across heat inputs. The results reveal that PVP-coated nanoplates achieved the highest thermal conductivity, increasing the heat transfer coefficient to 362 W/m²K at a 90 % filling ratio and 90° inclination—compared to 350 W/m²K for distilled water. Silica coatings demonstrated superior long-term stability. The findings highlight the potential of silver nanoplate-based nanofluids to significantly enhance thermal performance while providing insights into the effects of nanoplate morphology and coating materials. This work establishes a foundation for optimizing nanofluid-based heat pipes, contributing to advancements in thermal management systems across various applications.