Energy and exergy assessment of a photovoltaic-thermal (PVT) system cooled by single and hybrid nanofluids

Abstract

• The energy and exergy efficiencies of a PVT system are assessed numerically. • Single and hybrid nanofluids are employed at 0.2% and 0.3% concentrations. • Hybrid nanofluid disclosed superior performance over the single nanofluid. • PVT electrical exergy efficiency is reduced by 13% using TiO 2 -Fe 2 O 3 and by 11% using Fe 2 O 3 nanofluid. Photovoltaic-thermal (PVT) concept is a novel methodology to lower the PV module temperature and consecutively produce thermal and electrical energies. This study assesses the thermal and electrical advancements of a PVT system using iron oxide (Fe 2 O 3 ) single nanofluid and titanium oxide-iron oxide (TiO 2 -Fe 2 O 3 ) hybrid nanofluid at 0.2 % and 0.3 % concentrations. The PVT energy and exergy efficiencies were presented and analyzed concerning the effect of proposed single and hybrid nanofluids. Study findings disclosed that dispersing 0.3% of TiO 2 - Fe 2 O 3 nanocomposites into water has enhanced the nanofluid thermal conductivity, improving the Nusselt number by 90.64 %, while Fe 2 O 3 nanoparticles achieved 31.75 %. Furthermore, employing TiO 2 - Fe 2 O 3 -based nanofluid at 0.3 % has enhanced the PVT electrical efficiency by 13 % and, thermal efficiency by 44 % compared to Fe 2 O 3 -based nanofluid, which exhibited 12 %, and 33 %, respectively. Besides, the PVT electrical exergy efficiency was augmented by about 13 % using TiO 2 -Fe 2 O 3 -based hybrid nanofluid, against 11 % using Fe 2 O 3 nanofluid. Reversely, the pressure drop was increased by a maximum of 62.9% when TiO 2 - Fe 2 O 3 was applied due to the raised nanofluid density compared to the reference base fluid. Conclusively, hybrid nanofluid has a superior influence on the PVT performance than single nanofluids. However, further investigations are required to explore cost-effective hybrid nanofluids with a low pressure drop.

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