Multi-objective optimization of a concentrated spectrum splitting photovoltaic-thermoelectric hybrid system

•A comprehensive multi-objective optimization process is presented.•The key influencing factors of the coupling system are determined.•The coupling efficiency and efficiency difference are simultaneously optimized.•The two optimization objectives are proved to be negatively correlated.•The optimal photovoltaic bandgap and system operating conditions are obtained. This paper presents a comprehensive multi-objective optimization process of the concentrated spectrum splitting photovoltaic-thermoelectric hybrid system, including sensitivity analysis, parameter evaluation, and genetic algorithm. The coupling efficiency and the efficiency difference compared to the concentrated photovoltaic system are simultaneously taken as the optimization objectives. Theoretical models of the two systems are established. The key influencing factors are determined, and their effects on the operating temperatures and efficiencies are investigated. The Pareto front and optimal working conditions are acquired, and the impacts of the thermoelectric figure of merit on the optimization results are further studied. The results demonstrate that the photovoltaic bandgap, splitter cutoff wavelength, concentration ratio, cooling performance, and thermoelectric structure factor are the system's key influencing factors. The two optimization objectives are negatively correlated, attributed to the effect of the PV bandgap. The cost and lifetime need to be further considered to identify the optimal solution. For the current thermoelectric devices, the coupling system achieves the highest coupling efficiency at the photovoltaic bandgap of about 1.42 eV and the maximum system efficiency difference near the photovoltaic bandgap of 1.65 eV.