Hybrid thin-film photovoltaic-absorption heat transformer system for enhanced solar energy utilization

Conventional photovoltaic cells face inherent limitations in total solar energy conversion due to spectral mismatch and thermalization losses. To mitigate these limitations, the proposed system integrates a thin-film solar cell for electricity generation, a solar selective absorber for sub-bandgap photon harvesting, and an absorption heat transformer to upgrade the recovered low-grade heat to a higher temperature level. A coupled numerical framework integrates photovoltaic simulations with a thermodynamic absorption heat transformer model to evaluate system performance through power output density, energy efficiency, and exergy efficiency. The results indicate that the proposed hybrid system achieves a maximum power output density of 246.68 W/m2, an energy efficiency of 22.18%, and an exergy efficiency of 26.57%. These values represent theoretical upper limits, showing respective enhancements of 59.5%, 43.4%, and 59.4% over a standalone thin-film solar cell by cascading energy use. Parametric analysis identifies absorber thickness, interface defect density, and operating temperature as critical factors governing system performance. The research demonstrates that the integrated system enhances spectral utilization and waste-heat recovery, enabling improved solar energy conversion efficiency.