Nanofluids are colloidal systems broadly used in solar-energy utilization. The main disadvantages ofnanofluids are their instability and time-consuming preparation methods, the aim of the present workis to introduce a nanofluid without the mentioned p...
Nanofluids are colloidal systems broadly used in solar-energy utilization. The main disadvantages ofnanofluids are their instability and time-consuming preparation methods, the aim of the present workis to introduce a nanofluid without the mentioned problems.
Herein, two colloidal systems of vanadium including V/PEG (for the first time) and V/H2O nanofluidswere synthesized by laser ablation in liquid method in polyethylene glycol and water, respectively andutilized in light-to-heat conversion. V/PEG is more stable than V/H2O as the oxidation state of vanadiumis unchanged in polyethylene glycol but in water is changed until V2O5 is obtained. Unlike V/H2O, noagglomeration/precipitation takes place for V/PEG. Based on the images obtained from transmission electronmicroscopy, vanadium nanoparticles have different morphologies and sizes, helping V/PEG to absorbdifferent wavelengths, resulting in more heat generation. The surface temperature of V/PEG reached ffi 57℃ (DT ffi 30 ℃), under 60 min sunlight irradiation (0.9 Sun). The V/PEG was used at high light intensitiesand several successive heating–cooling cycles without losing its heat-generation performance. Differentcalculated thermo-physical parameters reveal that V/PEG is more eligible than V/H2O in photo-thermalconversion with several advantages: inexpensive and simple synthesis, dispersant-free, long-colloidalstability, high photo-thermal durability and high heat-generation efficiency.