Numerical and model validation of uncovered nanofluid sheet and tube type photovoltaic thermal solar system

Highlights: • A numerical model applied to analyze an uncovered nanofluid based PVT collector. • The model included nanoparticle concentration, types and different base fluids. • Numerical model are performed on Al₂O₃ and CuO nanoparticles (1, 2 and 4 wt %). - Abstract: In this paper, an experimental and numerical study is performed to evaluate the performance of a photovoltaic thermal (PV/T) nanofluid based collector. A two-dimensional numerical model is established to study the effects of using nanofluids as working fluid in PV/T collector. The model is validated experimentally by comparing the simulations with the experimental results. The influence of concentration (0.1, 0.2 and 0.4 wt.%), types of nanoparticles (Al₂O₃ and Cu) and different base fluids (pure water and ethylene glycol) on the electrical and thermal performance of the collector is investigated. Also, the model is applied to predict the annual electrical and thermal output of the PV/T for three different cities: Lyon (France), Mashhad (Iran) and Monastir (Tunisia). The results indicated that using pure water as a base fluid provides a higher performance in comparison with ethylene glycol. Using Cu/water gives the best thermal and electrical efficiency in comparison to Cu/ethylene glycol, Al₂O₃/water and Al₂O₃/ethylene glycol. It is also found that the thermal and electrical energy output for Monastir (Tunisia) climate condition is higher than that of Mashhad (Iran) and Lyon (France).