An exergy-economic analysis of a concentrated photovoltaic-thermal system with phase change materials cooled by a nanofluid in porous media

A 3D numerical model of a concentrated photovoltaic-thermal module, coupled with phase change materials in a porous domain and cooled by Alumina nanofluid is developed. Compared to available studies, less simplifying assumptions are applied to better understand the underlying heat transfer mechanism in a concentrated irra-diation model and its effect on photovoltaic performance. The effects of different phase change materials' melting temperatures and various porosities of the porous medium are analyzed to find the best configuration leading to the highest exergy output. The C18H38 phase change material in a porous medium with 85 % porosity showed the best performance. With the help of the nanofluid cooling, the model is able to keep the average photovoltaic temperature at 43.8 degrees C at peak irradiation of 935 W/m2 under 4 suns of concentration, resulting in a photovoltaic exergy efficiency of 14.6 %. Applying concentrated solar irradiation increases the power production per unit area of the photovoltaic by two to four times compared to similar photovoltaic-thermal systems in the literature. In addition to an 8-hour simulation, the system's viability is investigated via a yearly exergy-economic analysis. The yearly exergy production, levelized cost of electricity and discounted payback period are 258.23 kWh/year, 1.25 ¢/kWh and 10.48 years, respectively.