This research attempts to investigate the thermal performance of solar air collectors with pin fins and turbulators. Incorporating carbon-nanotube-based fins and turbulators in solar collectors can enhance their performance due to their high thermal conductivity, low weight, and high aspect ratio. In the present study, numerical analyses of a solar collector with pin fins and turbulators are carried out to investigate its effect on the Nusselt number. The paper begins with the numerical analysis of conventional air collectors and compares them with theoretical results. This is followed by numerical analyses, which are carried out to examine different configurations of the absorber plate with pin fins of varying diameters (10 mm, 20 mm, and 30 mm) and turbulators of varying heights (20 mm, 40 mm, and 60 mm) in the base plate. The analyses include variations in the Reynolds number ranging from 3000 to 15,000. Subsequently, after the performance of the solar collector with pin fins is evaluated, the effect of turbulators of varying heights on the Nusselt number is analyzed, followed by the analysis of the combined effect of pin fins and turbulators. The results are compared with traditional solar collectors and show that the combined effect of pin fins and turbulators can significantly improve the thermal performance of solar air collectors. The findings of this study can contribute to the development of renewable energy-based air conditioning, ventilation, and heating systems.

Due to their inherent advantages, micro-sized horizontal axis wind turbines (HAWT) are preferred over vertical axis wind turbines (VAWT) for urban applications. Typically, HAWTs on the market are constructed using steel, alloys, or fibre-reinforced composites, with the latter being the most economical and stable in comparison to steel and alloy-based HAWTs. Nevertheless, in light of the increased emphasis on cost savings and environmental sustainability, natural-fibre composites have become more desirable. This study focuses on the implementation of flax-fibre-reinforced HAWT wind blades designed for urban applications in particular. The proposed wind blades were designed using CATIA and their feasibility and performance were evaluated via numerical analyses in ANSYS. Structural, modal, and harmonic analyses were conducted under various loading conditions. The results indicate that flax-fibre-reinforced wind blades possess higher natural frequencies, greater stability, and lower deflection amplitudes at resonance frequencies than other materials.