Efficient direct absorption solar collector based on hollow TiN nanoparticles

Due to the unique geometric effects and excellent thermophysical properties, nanoparticles (NPs) have attracted significant attention in recent years. Compared to composite NPs, the hollow structures are expected to reduce the complexity of the synthesis process and improve the long-term stability of the nanofluids. In this work, we propose a direct absorption solar collector (DASC) based on hollow TiN NPs for efficient solar harvesting. The optical properties of the hollow NPs are investigated using the finite element method. Numerical results show that the photothermal conversion efficiency of hollow TiN can reach 92.64%, which is 7.18% higher than that of solid TiN with the same particle size. The potential physical mechanism can be explained by the fact that surface plasmon resonances are excited on the inner and outer surfaces of the hollow TiN NPs. Further, we investigate the effect of geometrical parameters of hollow TiN NPs on the performance of DASC. Our study demonstrates that hollow TiN NPs have a promising prospect in efficient solar thermal utilization.