Abstract
Abstract The present study investigates the theoretical and experimental potential of SiO 2 nanoparticles to enhance heat transfer in cooling water systems. In contrast to the conventional methods outlined in the extant literature, the SiO 2 nanoparticles were synthesized using a green approach, employing rice husks as the starting material. The resulting SiO 2 nanoparticles exhibited an average diameter of 20–35 nm. The study then proceeded to evaluate the effects of varying concentrations of SiO 2 (0.2%, 0.4% and 0.55%) on heat transfer in engine cooling water under two distinct engine loads (7 kW and 8.5 kW). The highest heat transfer enhancement was recorded at 64.3% for the 7 kW engine load and 67.5% for the 8.5 kW engine load, with an additive of 0.55% SiO 2 . A study was conducted to ascertain the stability of cooling water to which nanoparticles had been added. The results indicated that a homogeneous and non-settling mixture was obtained for a considerable duration. A preliminary economic evaluation was conducted to ascertain the feasibility of synthesizing SiO 2 using green methods. The study found that simple payback times were calculated below one year for all the SiO 2 ratios. The performance effects of the additive, which is naturally produced, economically and environmentally friendly, were evaluated technically and economically.