Experimental investigation of a solar photovoltaic-thermophotovoltaic cascade system with concentrating spectrum splitting and reshaping

Traditional solar energy systems face inefficiencies, as photovoltaic (PV) cells are unable to harness the full solar spectrum, while solar thermal systems generate significant irreversible losses during photo-thermal conversion. To address this issue, a novel solar photovoltaic-thermophotovoltaic cascade (PV-TPV) system was proposed that integrates thermophotovoltaic (TPV) technology to harvest the residual-spectrum that is not suitable for PV and establish an experimental test method. For the PV-TPV system composed of GaAs PV cell and GaSb TPV cell, the key components of spectrum splitter, solar absorber, and narrowband filter were manufactured. Spectrum splitting PV cell performance, residual-spectrum radiation captures performance, and TPV cell performance tests are carried out. The PV-TPV system performance was explored through experiments and modeling. The results show that the hybrid system has the optimal performance under the 300–900 nm spectrum splitting condition. The efficiency of the hybrid system is 22.67% with 1000 suns, which is 1.67 percentage points higher than that of a single GaAs cell. Under different concentration ratios, the efficiency of the PV-TPV system is also higher than that of a single solar TPV system. Combined with the cutting-edge TPV cell and concentrating GaAs cell, this study points out that the efficiency of the solar PV-TPV system can reach 31.67% under 1000 suns, which is 5.47 percentage points higher than that of a single concentrating GaAs cell. This study verified the performance superiority of the PV-TPV system from an experimental perspective, providing a new idea for the cascade utilization of the full solar energy spectrum.