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Hydrogen production from water using a catalyst and solar energy was an ideal future fue l source. In this study, an elaborate experimental test rig of hydrogen production from solar water splitting was designed and established with self-controlled temperature system. The effects of light intensity on the reaction rate of hydrogen production from solar water splitting were experimentally investigated with the consideration of optical losses, reaction temperature, and photo-catalysts powder cluster. Besides, a revised expression of full-spectrum solar-to-hydrogen energy conversion efficiency with the consideration of optical losses was also put forward, which can be more accurate to evaluate the full-spectrum solar-to-hydrogen energy of photo-catalysts powders. The results indicated that optical losses of solar water splitting reactor increased with the increase of the incoming light intensity, and the hydrogen production rate increased linearly with the increase of effective light intensity even at higher light intensity region when the optical losses of solar water splitting reactor were considered. [ABSTRACT FROM AUTHOR]

Semi-transparent solar-cell-based SBS PV/T system is promising. However, traditional semi-transparent solar cell-based SBS PV/T system can only produce low-grade thermal energy because the semi-transparent solar cell cannot concentrate long-wavelength sunlight. Even if a concentrating system is used, the semi-transparent solar cell must be able to withstand high temperatures, which increases the costs of the solar cell, and an additional bracket is required for installing the concentrator. In this study, the idea of using a single piece of photovoltaic (PV) to regulate the radiative transfer of the full solar spectrum for realizing the co-generation of electricity and high-grade thermal energy is proposed. A semi-transparent solar cell with a serrated groove structure at its bottom was fabricated. The solar cell can convert 400–800 nm wavelength photons to electricity, and focus 800–2500 nm wavelength photons on a small spot to produce high-temperature thermal energy. Therefore, the transmitted irradiance can be improved with a simple structure in a semi-transparent solar cell-based SBS PV/T system. [Display omitted] • Semi-transparent solar cell with serrated groove structure for SBS is proposed. • Idea of using a single piece of PV to regulate full solar spectrum is proposed. • Semi-transparent solar cell-based SBS PV/CST system is experimentally studied. • Feasibility of such novel system is validated by indoor and outdoor experiments. • The utilization efficiency of the full-spectrum solar energy can reach 77%. Semi-transparent solar cells can be used for spectral beam splitting (SBS) in which short-wavelength photons are converted to electricity and long-wavelength photons are transmitted to thermal absorbers. However, these thermal absorbers can only produce low-grade thermal energy because the semi-transparent solar cell cannot concentrate long-wavelength photons. In this study, based on the idea of regulating the radiation field to match the energy conversion on-demand, the strategy to use a single piece of photovoltaic (PV) to regulate the photon capture of the full solar spectrum for realizing the co-generation of electricity and high-grade thermal energy is proposed. A semi-transparent solar cell with a serrated groove structure at the bottom is designed and fabricated. The cell can convert 400–800 nm wavelength photons to electricity, and focus 800–2500 nm wavelength photons to a small spot to produce high-temperature thermal energy. A novel α-Si thin-film semi-transparent solar cell-based SBS hybrid photovoltaic/concentrated solar thermal system is established. The feasibility of the system is validated through indoor and outdoor experiments. The utilization efficiency of the full-spectrum solar energy can reach 77%. The high average concentrated irradiance of up to 4.31 KW/m2 transmitted through the semi-transparent solar cells is sufficient for high-temperature thermal utilization. [ABSTRACT FROM AUTHOR]

The mismatch between radiative intensity field and energy required for solar thermochemical reaction can cause serious heat waste and reduce energy conversion efficiency. To improve the energy conversion efficiency of solar to fuel, the radiative intensity regulation method to match energy conversion on demand in solar methane dry reforming is proposed in this study. The design of solar spots and biomimetic leaf hierarchical porous structures is investigated and optimized, which can realize a better radiative intensity field matching. The experimental and numerical studies show that, by using the method of regulating radiative intensity field to match energy conversion on-demand in solar thermochemical reactor, the methane conversion rate and solar thermochemical energy storage efficiency can be increased by 4.6% and 6.1%, respectively. The ideal synergy between real temperature field distribution and theoretical temperature requirement is perfectly achieved. [Display omitted] [ABSTRACT FROM AUTHOR]