Design and experimental investigation of a novel full solar spectrum utilization system

Abstract

Coupling multi-devices is a promising way to achieve efficient utilization of full spectrum solar energy. After analyzing and summarizing the advantages and disadvantages of the four most representative full solar spectrum utilization systems (tandem photovoltaic-thermoelectric PV-TE system, tandem photovoltaics/thermal PV/T system, spectrum splitting PV-TE system, and spectrum splitting PV/T system), three recommendations for optimization design of a full solar spectrum utilization system with high efficiency are proposed based on the principle of spectral matching and cascade utilization of energy. Then, a novel full solar spectrum utilization system is presented, namely, the photovoltaics-thermoelectric/thermal (PV-TE/T) system. The PV-TE/T system is mainly composed of a tandem PV-TE component and a thermal collector with spectrally selective absorbing fluid. In order to prove that the PV-TE/T system has better performance, the experiments of performance comparison that a PV standalone system and a tandem PV-TE system are set to compare with the PV-TE/T system were conducted under the same concentration and ambient condition. Due to the fluctuation of solar energy, the experiments of performance comparison were conducted in sunny and cloudy day. In sunny day, the output power of PV-TE/T system is increased by 11.2% compared to the tandem PV-TE system, and this ratio is increased to 35.6% in partly cloudy day due to the thermal collector. Therefore, the thermal collector in PV-TE/T system can make the output power more stable, also diversify the methods of the solar energy utilization. Moreover, an experiment of matching effect between light and heat that a PV-TE/T system with single-layer antireflective glass is compared with that with double-layer antireflective glass was conduct. Although single-layer antireflective glass leads to better performance in PV-TE/T system, its advantage of the single-layer antireflective glass becomes small as the fluid temperature increases (in the end, the output power of the PV-TE/T system with single-layer antireflective glass is just 2.6% higher than that with double-layer antireflective glass). In conclusion, the PV-TE/T system has great potential for application, and its further improvements is supposed to focus on the photovoltaics and glass.