Synergizing concentrated spectral-splitting PV/T with thermally regenerative electrochemical cycle and radiative cooling for 24-hour power generation

To address the dual challenges of limited full-spectrum solar energy utilization and solar power intermittency, this study proposes a novel system capable of enabling continuous 24-h power generation. It integrates a concentrated photovoltaic/thermal (CPV/T) unit, a spectral splitter (SS), a thermally regenerative electrochemical cycle (TREC), and a radiative sky cooler (RSC). This integration adopts a daytime heat storage for nighttime power generation strategy. Specifically, waste heat harvested from the PV and TREC modules during daytime is stored to drive the TREC at night. Concurrently, the RSC maintains the TREC cold side at a sub-ambient temperature, thereby enhancing nighttime power output. Dynamic simulations under real meteorological conditions demonstrate the system's capability for stable 24-h operation. During daytime, the PV and TREC modules achieve peak power densities of 1713.98 W/m2 and 98.23 W/m2, respectively. At night, the TREC module delivers a maximum power density of 35.77 W/m2. Parametric analyses identify the optimal spectral splitter cutoff wavelength as 880 nm, which aligns with the PV absorption edge. Additionally, increasing the tank water mass and the cooling water mass flow rate both contribute to enhanced system performance. Annual performance assessments show that the system achieves a total energy density of 2701.63 kWh/m2. Notably, the integrated RSC contributes a 2.37% annual performance improvement. Furthermore, the TREC module demonstrates superior electrical efficiency, exceeding that of a comparable thermoelectric generator by more than fourfold. These findings confirm that the proposed system provides a viable technical pathway for efficient full-spectrum solar energy utilization and continuous power supply.