Benchmark assessment of performance indices of a selection of hybrid nanofluids in a hybrid photovoltaic/thermal system

Abstract

Abstract This research is a study assessing the performance of hybrid nanofluids in hybrid photovoltaic (PV)–thermal systems. This study addresses 10 hybrid nanofluids applied to hybrid PV–thermal systems. The transition to carbon-free energy can mitigate the worst effects of climate change, ensuring that global sustainability is addressed. Clean energy is now responsible for one-third of the global capacity, of which 20% is attributed to solar energy. Renewables continue to be economically viable, with declining costs driving growth. This study aims to compare the yearly performances of a model hybrid PV–thermal system using 10 different hybrid nanofluids. Hybrid nanofluids constitute two or more dissimilar materials stably suspended in a base fluid (e.g. water). MATLAB and COMSOL Multiphysics® computational fluid dynamics software are employed together for the benchmarking assessment with good agreement observed. Various fluid inlet temperatures (Tin ∈ [300, 360] K), nanofluid volume concentrations (φ ∈ [0, 4]%) and storage-tank volumes (V ∈ [50, 300] L) were simulated. The meteorological data applied were those for Lagos, Nigeria (6° 27’ 55.5192” N, 3° 24’ 23.2128” E). The assessment based on analytical-numerical solutions reveals that the thermal enhancement by hybrid nanofluids ranges from 6.7% (graphene oxide [GO]—multiwalled carbon nanotube [MWCNT]/water) to 7% (ZnO—Mn–ZnFe2O4/water) for φ = 2% and V = 300 L. The yearly exergy efficiency ranges from 2.8% (ZnO—Mn–ZnFe2O4/water) to 2.9% (GO—MWCNT/water), also for φ = 2% and V = 300 L. These findings have implications for a vast range of industrial processes, expanding the knowledge that is critical to a sustainable future. A combined solar PV-thermal system that stores thermal energy using nanofluids is modelled. Hybrid nanofluids (two or more dissimilar materials stably suspended in a base fluid) are shown to enhance the annual electrical, thermal and exergetic outputs of the system.