Optimizing photovoltaic thermal systems with ternary hybrid nanofluids: Statistical and regression analysis

Abstract

This study explores the intricate interplay between ternary hybrid nanofluids and their impact on the electrical and thermal efficiencies of Photovoltaic Thermal systems (PV/T), considering a diverse range of nanomaterial shapes. It meticulously scrutinizes these systems within a structured framework, incorporating phase change materials and strategically positioned cylinders, leveraging advanced numerical methodologies for detailed analyses. This comprehensive investigation systematically amalgamates multiple nanomaterials and crucial parameters, offering invaluable insights into the optimization of PV/T performance within complex fluid dynamics and configurations. Examining the electrical and thermal efficiencies of the PV/T system using ternary hybrid nanofluids with nanomaterials suspended in variously shaped base fluids, this research involves a three-dimensional domain housing a rectangular block with a square base. This block integrates a phase change material (PCM), and its interior features four equally spaced circular cylinders regulating the flow of ternary hybrid nanofluids. Atop this block sits a PV panel comprised of glass, a silicon layer, and a copper absorber. The study incorporates three nanomaterials—multi-walled carbon nanotubes (MWCNT), alumina, and copper—suspended in water, each with unique shapes. These four cylinders are strategically positioned along the block’s length at 20 %, 40 %, 60%, and 80%, assuming the block’s height constitutes 20 % of its length. Utilizing the finite element method with the incompressible Navier-Stokes equations and heat equation in three dimensions, the investigation employs the conjugate heat transfer interface within COMSOL Multiphysics 6.0. It encompasses a broad array of numerical, statistical, and regression analyses to delve into the electrical, thermal, and phase transition characteristics of paraffin wax. The study scrutinizes four fundamental parameters: Reynolds number (ranging from 100 to 1000), total volume fraction of nanomaterials (ranging from 1 % to 10 %), shape factors (ranging from 3 to 5.7), and an aspect ratio (with the cylinder’s diameter-to-length ratio between 0.3 and 0.5). The present study reports an average electrical efficiency of 8.14 % for the PV/T system while achieving a maximum thermal efficiency of 71.62 %. Regression analyses indicate enhancements of 0.000008675, 0.00775855, and 0.00014403 in electrical efficiency per unit increase in Reynolds number, total volume fraction, and aspect ratio, respectively. Likewise, thermal efficiency shows improvements of 0.00000738889, 0.00482906, and 0.000118775 for one-unit increments in Reynolds number, volume fraction, and shape factor, respectively.