فهرست نشریات علمی دسترسی آزاد ایران

This research explores the thermal performance improvement of a U-tube evacuated tube solar collector (ETSC) using a Ferric/water nanofluid as the working medium. The nanofluid was synthesized using a two-step method with different volume concentrations ranging from 0.25% to 2.0% Fe+3 nanoparticles. Stability was enhanced through the use of surfactants, and confirmed using zeta potential testing. Thermophysical properties such as thermal conductivity, specific heat, and viscosity were examined across a temperature range of 25°C to 50°C. Results show that increasing nanoparticle concentration improved thermal conductivity by up to 13.04%, while reducing specific heat capacity. The collector’s performance was tested under various mass flow rates and concentrations. The highest temperature difference recorded was 9.9°C at 1.0% concentration and 0.0083 kg/s flow rate. Maximum energy efficiency reached 72.56% at 1.25% concentration and 0.00416 kg/s. Entropy generation was lowest at 26.19 W/K for 1.5% volume concentration, indicating reduced irreversibility. An uncertainty analysis confirmed that measurement errors decreased at higher flow rates, supporting the reliability of the findings. The study concludes that Ferric/water nanofluid enhances the heat transfer and overall efficiency of ETSC systems.