Systematically investigating solar absorption performance of plasmonic nanoparticles

Harvesting solar energy by adding nanoparticles (NPs) to the base fluid is an effective way to improve solar absorption efficiency. However, the plasmonic NPs used in the solar thermal applications are usually some noble metals (such as: Au and Ag) without consideration of economics, making it difficult for actual engineering applications. In this work, 13 kinds of plasmonic materials are considered and compared based on the solar absorption performance of NPs. Results show that the Cu NP has both great solar absorption performance and low cost. However, Cu is easily oxidized in the air or water. A SiO2 coating is designed around the Cu NP to prevent Cu from being oxidized. The Cu NP can achieve the higher solar absorption ability per unit volume when the radius is 20 nm-30 nm. In addition, the SiO2 coating can enhance the solar absorption performance of Cu NPs and the highest power absorption per unit volume can be obtained when the core-shell ratio of Cu@SiO2 NP is 5/7. Finally, calculation results show that NP agglomeration in the base fluid would further improve the solar absorption performance. This work provides an effective candidate for the engineering utilization of plasmonic NPs in solar thermal applications. (C) 2020 Elsevier Ltd. All rights reserved.