Critical Examination of the Role of Silica Nanoparticle Dispersions in Heat Transfer Fluid for Solar Applications

Silica nanoparticles are eco-friendly with high heat transfer potential due to their low-cost synthesis, abundant natural resources, and mass production. Silica nanoparticles with advantages such as biocompatibility, ease-of-functionalization, and large surface area are widely employed in solar applications. Silica nanoparticles possess excellent properties such as good photoconductivity, ideal thermal expansion, high corrosion resistance, and long-term durability, which improve the system's overall efficiency. Dimethyldichlorosilane was employed to prepare silica nanoparticles into hydrophobic nanoparticles. The titration method computed the hydroxyl number of silica nanoparticles and reduced it after modification. The novelty of this work is to enhance the overall efficiency of the solar water heater by adding silica nanoparticles in heat transfer fluid owing to its higher thermal stability, heat resistance and improved structural properties of the nanoparticle. This work reveals a detailed study on the effect of silica nanoparticles on the performance parameters of the solar water heater. Silicon nanoparticles are dispersed with water using NaOH for pH adjustments and Cetyl Triammonium Bromide (CTAB) (1% by wt) as the dispersant to accelerate the vaporization and heating of the medium by local nanoscale heating. This study proposes that incorporating silica nanoparticles at different mass fractions shall improve the s overall efficiency of solar collectors. Silica nanoparticles are dispersed into water with and without using surfactant inside the absorber riser tubes for different mass fractions. The efficiency of the solar flat plate collector is calculated using the ASHRAE method. A collector of the area of 0.5 m2 of 25 LPD has been envisioned and made up with necessities to insert T-type thermocouples to study the temperature distribution. The weight fractions used are 0.2%, 0.4%, and 0.8%, and the experimental results showed an improved heat transfer was pragmatic in the collector using nanoparticles. The efficiency of the solar collector is improved by 2.5, 5.1 and 8.4% by adding Silicon dioxide nanoparticles at 0.2%, 0.4%, and 0.8% weight fractions, respectively. This study concludes that silicon oxide possesses high heat transfer potential and shall be employed in thermal systems.