Numerical modelling and optimization of solar nanofluids

Abstract

Direct Absorption Solar Collectors (DASCs) have gained popularity as a new and promising design for solar collector systems. DASCs utilize nano uids to absorb solar energy directly; eliminating the need for an absorber tube, and providing increased e ciency. Nano uids are dilute suspensions with dispersed nano-sized particles that show good thermal and optical or radiative properties. This study focuses on optimizing the overall system e ciency of a at plate collector system using nano uids. Core shell and pure nanoparticles are considered along with water and ethylene glycol as base uids. Core-shell nanoparticles are spherical particles with multiple layers of di erent materials that can be selected for optimal absorption characteristics. The collector model considers direct absorption of solar energy by a owing nano uid, while the spectral radiative properties of the nano uid are predicted based on Lorenz-Mie theory. Di erent volume fraction, particle size and shell thickness values are considered for each nano uid type, and optimal parameters are determined.