Plasmonic nanofluids for high photothermal conversion efficiency in direct absorption solar collectors: Fundamentals and applications

Abstract

With growing interest in the use of solar thermal applications to produce renewable and sustainable energy, coupled with the remarkable progress being made in nanotechnology, many innovative solutions have been proposed to improve the performance of solar energy harvesting technologies. Plasmonic nanofluids based on noble metallic nanoparticles are promising media for direct absorption solar collectors, which exploit localized surface plasmon resonance to enhance absorptivity within the solar spectrum. Plasmonic nanofluids can be used to control spectral absorption and scattering efficiencies by tailoring the morphologies of plasmonic nanoparticles. The absorption characteristics can be tuned to match the incident solar radiation, which boosts energy conversion efficiency, even at very low concentrations of nanoparticles. This reduces the collector's pumping power. The spectral absorption characteristics can also be exploited in photovoltaic/thermal systems by increasing the nanofluid transmissivity only in the photovoltaic working bands. This paper presents a comprehensive review of plasmonic nanofluids for solar thermal applications, including the design and development methods of new plasmonic materials. Understanding solar simulator concepts is also crucial for verifying and validating the use of spectral selective plasmonic materials in volumetric absorption solar collectors under normal or high flux irradiance. The optical characteristics of plasmonic nanofluids are reviewed along with the latest developments in conventional and novel materials for various solar thermal applications.