Enhanced operational efficacy of direct absorption solar collectors using multi-walled carbon nanotubes/MoS2 nanofluids

This study investigates the impact of two nanofluids-carboxyl-functionalized multi-walled carbon nanotubes (MWCNTs) in water and molybdenum disulfide nanoparticles (MBDN) in water-on the performance of direct absorption parabolic solar collectors. An experimental setup was utilized to measure thermal and exergy efficiencies across a range of nanofluid concentrations. Experiments were conducted under controlled flow conditions, varying flow rates and inlet temperatures to simulate realistic solar conditions. The MWCNT nanofluid demonstrated the highest thermal efficiency, reaching 46.4%, while the MBDN nanofluid achieved a thermal efficiency of 37.1%. Notably, a combination of both nanofluids yielded a thermal efficiency of 52.14%, exceeding that of distilled water. At maximum flow rates and temperatures, exergy efficiencies were evaluated for each fluid, with the hybrid nanofluid exhibiting the highest value at 5.26%. Pressure drops within the system remained low for all tested nanofluids, indicating an effective enhancement of thermal performance in direct absorption solar collectors.