Optimized energy distribution management in the nanofluid-assisted photovoltaic/thermal system via exergy efficiency analysis

Configuring a nanofluid spectrum splitter (NSS) with the thermally decoupled photovoltaic/thermal (PV/T) system is a feasible approach to achieve net-zero emissions. In this work, the gold nanofluid was used in the PV/T system as an optical filter because of the abilities to manage energy balance and enhance thermal collection. The energy distribution management was optimized via the NSS thickness ( L ) and nanoparticle concentration ( C ) based on exergy efficiency analysis. The results indicated that a higher nanoparticle concentration and NSS thickness enhanced output thermal energy and solar utilization efficiency. The solar utilization efficiency and merit function reached 88.50% and 2.48 at  C  = 75 ppm and L  = 20 mm if the worth factor ω  = 3. Furthermore, the optimized concentration was only 20 ppm, which achieved the highest exergy efficiency of 13.71%.The NSS-assisted PV/T device reached the highest equilibrium temperature of 49.9 °C at L  = 18 mm. Moreover, the exergy efficiency reached 12.77%, which was higher than that at L  = 22 mm, due to the heat loss. These findings suggest that energy distribution can be flexibly controlled according to the demand of service users, and an optimized NSS thickness can improve thermal energy storage .