Energy and exergy analysis of a hybrid photovoltaic/thermal-air collector modified with nano-enhanced latent heat thermal energy storage unit

Electrical and thermal energy can be generated simultaneously by using photovoltaic-thermal (PVT) systems. Also, electrical efficiency can be enhanced by cooling the PV panel. In this study, three different PVT-air collectors have been designed, manufactured and experimentally analyzed including conventional (PVT), with paraffin-based thermal energy storage unit (PVT-TES) and with nano-enhanced paraffin-based thermal energy storage unit (PVT-NeTES). Copper oxide (CuO) nanoparticles (1 wt%) have been utilized to upgrade the thermal conductivity of the phase change material. Tests have been performed in two flow rates (0.007 and 0.014 kg/s). According to experimental results, overall exergy efficiencies for PVT, PVT-TES and PVT-NeTES were achieved between 10.52-13.59%, 11.08-14.36% and 12.52-15.44%, respectively. Moreover, sustainability index (SI) values were attained in the range of 1.12-1.16, 1.13-1.17 and 1.14-1.18, respectively. Obtained findings showed that utilizing nano-enhanced thermal energy storage system and increasing flow rate significantly upgraded both electrical and thermal performances of the PVT system.