Performance analysis of a hybrid photovoltaic-thermoelectric generator system using heat pipe as heat sink for synergistic production of electricity

Highlights: • Flat plate heat pipe is introduced as heat sink in hybrid photovoltaic-thermoelectric generator system. • Comparative analysis between the bifacial and the conventional tandem photovoltaic-thermoelectric generator system is conducted. • Influence of different solar concentration ratios, convective heat transfer coefficients, external load resistances and working fluids is investigated. • A maximum increase of 20.98% in power output and 14.05% in electrical efficiency is observed for the bifacial system. The conventional tandem photovoltaic-thermoelectric generator (PV-TEG) system has proved the feasibility of solar full-spectrum utilization technology. Nevertheless, the inconsistent operating temperature range for PV and TEG impedes the development of this technique. Hence, to tackle the challenge of mismatch operating temperature issues, a developed bifacial PV-TEG system combined with flat plate heat pipe (FPHP) is proposed in this study. A 3D numerical model has been built to make a comparative analysis between the bifacial FPHP-PV-TEG system and the conventional tandem FPHP-PV-TEG system. The influences of solar concentration ratio, convective heat transfer coefficient, external load resistance, different working fluids on the output power and conversion efficiency are analyzed. The obtained results indicate that the comprehensive performance of the proposed bifacial FPHP-PV-TEG system is superior to that of the conventional tandem FPHP-PV-TEG system. An increase of 20.98% and 14.05% in overall power generation and energy conversion efficiency could be achieved in bifacial FPHP-PV-TEG system compared with tandem FPHP-PV-TEG system, when the solar concentration ratio is 6 and the convective heat transfer coefficient is 1200 W/m²/K. Moreover, the behavior of the two systems could be enhanced by increasing the solar concentration ratio and the convective heat transfer coefficient. Besides, using water as working medium exhibits the best performance followed by ethanol and acetone in the bifacial FPHP-PV-TEG system, while the variation of working medium in tandem FPHP-PV-TEG system could be almost neglected.