Experimental study of a novel spectrally split photovoltaic-concentrated photothermal system

This paper proposes a novel photovoltaic-concentrated photothermal integrated system based on thin-film spectral splitting technology, realizing electricity-heat cogeneration by combining photovoltaic cells with thermal collectors. A spectrally selective film was coated on the parabolic concentrator surface to achieve precise solar spectrum segmentation: the photovoltaic responsive band is highly transmitted to the underlying photovoltaic cell for photoelectric conversion, while the non-responsive band is efficiently reflected and focused to the photothermal receiver for thermal utilization. Natural-condition experiments demonstrate that this design stabilizes photovoltaic incident energy and electrical output stability; concentrated utilization of the non-responsive band also elevates thermal energy grade and energy recovery efficiency. At a working fluid flow rate of 0.0083 kg/s, the system reaches an average total energy efficiency of 43.1% and average total exergy efficiency of 24.6%. Benefiting from effective structural decoupling of the two subsystems, operating parameters only regulate thermal performance without interfering with photovoltaic electrical performance, enabling independent regulation and collaborative optimization of multi-energy outputs and providing technical feasibility for full-spectrum solar energy utilization.