A novel spectrum allocation method in the photovoltaic-thermochemical hybrid solar system

Abstract

This paper proposes a novel spectrum allocation method for the spectral splitting photovoltaic-thermochemical hybrid system. In this new spectrum allocation method, the spectral beam splitter of the hybrid system has varying cutoff wavelengths along the reaction tube to adjust the wavelengths range of the spectrums allocated to the different segments of the thermochemical reactor. The solar thermal energy distribution on the thermochemical reactor is optimized to be matched with the energy demands of the thermochemical reaction. We have carried out the theoretical and experimental investigations of this new spectrum allocation method in our proposed photovoltaic-thermochemical hybrid system. Analysis shows that the solar energy allocated to the outlet segment of the reaction tube is reduced and the solar thermal energy distribution along the thermochemical reactor is optimized effectively. As a result, not only the heat loss of the thermochemical reactor is reduced, but the power output of the photovoltaic cells is improved. The experimental results show that the solar-to-electric efficiency of the hybrid system with the new spectrum allocation method reaches 23.3%, which is 4% higher than the conventional system with uniform cutoff wavelength.