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A revised water-assisted synthesis system (RWAS) was used to fabricate carbon/water nanofluids (CWNFs). The CWNFs were manufactured by heating graphite rods at different temperatures (700, 800, 900, and 1000°C). Aspects of the CWNFs and suspended nanocarbon, such as the morphology, structure, optical characteristics, and production rate, were fully characterized. Furthermore, the suspension performance of the CWNFs was controlled by adding a dispersant (water-soluble chitosan) at different concentrations. Finally, the CWNFs were determined to assess the influence of both the heating temperature of the graphite rod module (process temperature) and the dispersant concentration on the fundamental characteristics of the CWNFs. The results showed that the nanocarbon was a mixture of nanocrystalline graphite and amorphous carbon. Heating the graphite rod module at higher process temperatures resulted in a higher production rate and a greater nanocarbon particle size. Furthermore, adding dispersant could improve the suspension performance; increase the viscosity, density, and specific heat; and reduce the thermal conductivity of the CWNFs. The optimal combination of the process temperature range and dispersant concentration was 800 to 900°C and 0.2 wt.%, respectively, based on the production rate, suspension performance, and other fundamental properties of the CWNFs.

A thermal management system using alumina (Al2O3)/water as the nanofluid for green power sources was experimentally assessed in this paper. Basic thermal principles and formulas were utilized to evaluate the performance of an air-cooled heat exchanger. The Al2O3/water nanofluid was produced at the concentrations of 0.5, 1.0, and 1.5 wt.%. The testing conditions of this experiments were above three concentrations, five coolant flow rates (0.8, 1.2, 1.6, 2.0, and 2.4 L/min.), and three heating powers (50, 100, and 150 W). Firstly, basic properties of nanoparticles were analyzed. Fundamental relationships of the Al2O3/water nanofluid with respect to temperatures and concentrations were measured such as: viscosity, density, and specific heat. Next, an innovative concept named efficiency factor (EF) was proposed to quantitatively evaluate the thermal system performance. The enhancement of thermal system performance compared with distilled water was then defined as an efficiency factor ratio (REF). The experimental results demonstrated that the efficiency factor ratios were optimal at low flow rate (0.8 L/min.) and low concentration (0.5%). Values ofREFwere all below 1.0 at high flow rates (1.2–2.4 L/min.). This research points out the direction of optimizing a thermal management system for green energy sources in the near future.

The 0.5 wt.% multiwalled carbon nanotubes/water nanofluids (MWNFs) were produced by using a two-step synthetic method with different types and concentrations of stabilizers. The static position method, centrifugal sedimentation method, zeta potential measurements, and rheological experiments were used to assess the stability of the MWNFs and to determine the optimal type and fixed MWCNTs-stabilizer concentration of stabilizer. Finally, MWNFs with different concentrations of MWCNTs were produced using the optimal type and fixed concentration ratio of stabilizer, and their stability, thermal conductivity, and pH were measured to assess the feasibility of using them in heat transfer applications. MWNFs containing SDS and SDBS with MWCNTs-stabilizer concentration ratio were 5 : 2 and 5 : 4, respectively, showed excellent stability when they were evaluated by static position, centrifugal sedimentation, zeta potential, and rheological experiments at the same time. The thermal conductivity of the MWNFs indicated that the most suitable dispersing MWNF contained SDBS. MWNFs with MWCNTs concentrations of 0.25, 0.5, and 1.0 wt.% were fabricated using an aqueous SDBS solution. In addition, the thermal conductivity of the MWNFs was found to have increased, and the thermal conductivity values were greater than that of water at 25°C by 3.20%, 8.46%, and 12.49%.

In this study, tungsten trioxide (WO3) thin films were electrodeposited on indium tin oxide (ITO) glass to form WO3-coated glass. The electrodeposition (ED) time (tED) and ED current (IED) were varied to control the film thickness and morphology. Furthermore, the crystallization of the thin films was controlled by annealing them at 250°C, 500°C, and 700°C. The results showed that the thickness of the WO3thin films increased withtEDandIED. The as-deposited thin films and those annealed at 250°C were amorphous, whereas the WO3thin films annealed at 500 and 700°C were in the anorthic phase. Moreover, the amorphous WO3-coated glass exhibited high transmittance in visible light and low transmittance in near-infrared light, whereas the anorthic WO3-coated glass had high transmittance in near-infrared light. An empirical formula for determining the thickness of WO3thin films was derived through multiple regressions of the ED process parameters.