Optimisation of flow and fluid properties of nanofluids to enhance the performance of solar flat plate collector using MCDM technique

In this research work, aluminium oxide (Al2O3), copper oxide (CuO) and gold (Au) nanofluids are prepared with the volume concentrations of 0.1%, 0.2%, 0.3% and 0.4% nanoparticles and tested in solar flat plate collector to estimate the heat transfer characteristics and collector efficiency. The influence of the input variable such as material (type of nanofluid), nanoparticle concentration and the mass flow rate (such as 0.016 kg/s, 0.033 kg/s and 0.05 kg/s) are studied experimentally. With the aim of determining the best possible heat transfer and the collector efficiency with minimum pressure drop, the parameters were optimised using multi-criterion decision-making (MCDM) optimisation techniques. Considering the rate of heat transfer, collector efficiency and drop in pressure are the objective functions, the prime ranks of the optimised variables were obtained using TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) and MOORA (Multi-Objective Optimization on the basis of Ratio Analysis) techniques. Finally, the prediction accuracy of the models and the confidence levels were evaluated and analysed through ELECTRE (ELimination Et Choix Traduisant la REalite) method to create the hypothesis of the experiment. Al2O3 nanofluid with 0.1% and 0.2% volume concentrations of nanoparticle at 0.05kg/s mass flow rate was obtained as best alternatives from others and it shows good agreement between experimental analysis and optimisation techniques. While using, when compared to water, Al2O3 nanofluid with 0.05kg/s containing 0.1% and 0.2% nanoparticle concentrations, the enhancements were found to be 11.25% and 14.45%, respectively, for heat transfer rate; 11.16% and 14.34%, respectively, for collector efficiency; and 22.7% and 37.7%, respectively, for pressure drop across the collector.