Performance optimization of a nanofluid-based photovoltaic thermal system integrated with nano-enhanced phase change material

In this study, a nanofluid-based photovoltaic thermal system integrated with nano-enhanced phase change material is numerically simulated using a transient three-dimensional model. Aluminum oxide nanoparticles are dispersed into both the heat transfer fluid, which is water, and the Rubitherm series of organic phase change material. Response surface methodology is applied to gain a predictive model for estimating the behavior of the system in terms of four different design parameters of phase change material layer thickness, heat transfer fluid mass flow rate, and the mass fraction of nanoparticles through the phase change material and working fluid. The relationships between the mentioned parameters and responses, including electrical and thermal power, exergy, and entropy generation along with their interaction impacts on system performance are obtained. Finally, employing single and multi-objective optimization, different scenarios are defined to optimize the system based on the designer's goals. The results reveal that the dispersion of nanoparticles within the heat transfer fluid leads to a better improvement in photovoltaic thermal system performance compared to its addition to the phase change material. Based on the multi-objective optimization method to maximize electrical and thermal exergies, simultaneously, results show the best electrical and thermal exergies of the system can be achieved to 135.92 and 2.44 W/m², respectively.