Nanofluid-based optical filter optimization for PV/T systems

Abstract

Optical filters are essential in a wide range of applications, including optical communications, electronics, lighting, optical sensors and photography. This article presents recent work which indicates that optical filters can be created from specialized nanoparticle suspensions. Specifically, this article describes a theoretical optimization process for designing nanofluid-based filters for hybrid solar photovoltaic/thermal (PV/T) applications. This particular application is suitable because nanofluids can be utilized as both volumetric solar absorbers and flowing heat transfer mediums. The nanofluid filters described in this work compare favorably with conventional optical filters for five photovoltaic (PV) cell alternatives: InGaP, CdTe, InGaAs, Si, and Ge. This study demonstrates that nanofluids make efficient, compact and potentially low-cost, spectrally selective optical filters. Fluid-based optical filters could serve as efficient, compact and low-cost components for use in hybrid solar collectors. This is the finding of a recent theoretical study in which Robert Taylor at the University of New South Wales, Australia, together with colleagues in Australia and the USA, who studied the optical properties of nanoparticles suspended in liquids. These ‘nanofluids’ can be engineered to filter light (through selective absorption) for a variety of photovoltaic cells with expected efficiencies comparable to those offered by conventional solid-state filters. As fluids, the suspensions can also be used for transferring and storing thermal energy. These characteristics are helpful for improving the design of hybrid solar collectors, which combine photovoltaic conversion of light into electricity with direct-absorption of thermal energy.