Concentrated solar light splitting using cold mirrors for photovoltaics and photonic hydrogen production applications

In this study, an experimental setup is constructed to investigate the utilization of solar light splitting mirrors in photovoltaic (PV) cell and photonic hydrogen production applications by varying the solar light intensity on the system components. In the experimental setup, the solar rays are split to be used by PV cells using six cold mirrors, and Fresnel lens are employed to concentrate the light for utilization. The experimental unit is modeled using the equivalent circuit diagram of the PV cell, and the results provided by the model are then compared with the ones obtained from the experiments. The PV module conversion efficiencies are comparatively illustrated for concentrated light and non-concentrated light together with and without solar light splitting. The lower wavelength of the spectrum is directed to a photoelectrochemical hydrogen production reactor which uses a copper oxide photocathode. It is derived from the results that, although solar light splitting significantly decreases the portion of wavelengths received by the PV panel, the total generated power can be increased or kept at same levels by concentrating the sun rays. The power output from the measured PV module increases to 6.75 W from 3.50 W, which yields a considerable rise in the efficiency from 6.7% to 13.2% under the concentrated and divided light spectrum, while approximately 19% of the entire spectrum energy is received by the PV module. The power obtained from the PV module is used electrify the PEM electrolyzer for further hydrogen production. The temperature levels on the surface of the PV panel reach considerably high values corresponding to approximately 125 °C in some cases for a conventional PV module which then reduce the long-term stability of power generation. This is a challenge and requires cooling, utilization of high-temperature resistant materials in the PV module design, or employment of PV/T panels where the heat is extracted as a useful output or supplied to the PEM electrolyzer for heating the water before its disassociation which helps improve the performance.