Modeling of a novel nanofluid-based concentrated photovoltaic thermal system coupled with a heat pump cycle (CPVT-HP)

The concentrated photovoltaic thermal (CPVT) system is one of the heat and power generation systems that have received special attention in recent decades. In this paper, a novel CPVT system with Al2O3 nanofluid flow into porous channel coupled with a domestic heat pump (CPVT-HP) is evaluated from energy, exergy and economics viewpoints. In addition, mass flow rate of the nanofluid through the CPVT is thermo-economically optimized. The study is divided into three parts of Computational fluid dynamics (CFD) analysis of the CPVT, optical analysis of parabolic trough concentrator (PTC) and thermo-economic analysis of the proposed CPVT-HP system. The continuity, Brinkman momentum and energy equations are employed as governing equations for CFD analysis considering the average solar flux using optical calculations. Then, energy-exergy-economic optimization is performed on the proposed domestic CPVT-HP system in Mashhad city of Iran during November to February. The validation results show that the numerical simulation obtained for the proposed model has an acceptable agreement with the experimental data. Results show that with increasing the nanofluid mass flow rate, the PV cell temperature and nanofluid outlet temperature decease which lead to increases in PV cell efficiency and CPVT energy efficiency while the exergy efficiency of the CPVT system decreases. It is also found that the maximum performance of the porous channel collector is obtained for the pore diameter and the porosity of 0.9 mm and 95%, respectively. Finally, based on energy-exergy-economic analysis and Pareto method, the optimal nanofluid mass flow rate of the integrated CPVT-HP system is achieved equal to 0.01382 kg/s.