Enhancing the thermo-economic performance of mobile solar desalination system with dual reflectors, phase change materials and insulator cover: Experimental investigations

Abstract

• Insulator on top surface enhances the performance substantially. • Micro high conductivity particles are recommended for PCM. • Optimum angle for reflectors is critical. • More than double the productivity is achieved with modifications. A deficit of consumable water is the primary challenge to the people living on the seashore, tiny islands and remote regions. Although solar desalination is indeed one of the sustainable methods for producing sweet water from any form of polluted water, the low productivity of conventional systems remains a challenge. From this perspective, this research focuses on enhancing the productivity of a hemispherical solar desalination system by employing external dual reflectors, thermal conductivity enhanced latent heat storage medium and an insulator cover on the top surface during off-sun-shine hours. The experimental study is carried out in Coimbatore (India) during the March, April and May months of 2021. The experimental data are validated using uncertainty analysis, statistical analysis, and theoretical temperature data obtained from energy analysis. The novelty of the work includes the optimization of reflectors’ tilt angle, employing micro high conductivity particles embedded in energy storage medium and insulator cover on the top surface during the energy retrieval period. Because of the modifications, the proposed system can enhance productivity by 115% and energy efficiency by more than 100%. Although the system with a pure storage medium and the one with composite material exhibit more or less similar energy efficiency, the higher exergy efficiency of the latter during off-sun-shine-hours makes it superior to the former. Furthermore, the modified system is found to be economically viable as the cost of freshwater per litre and payback were reduced by 18% and 19% respectively as compared to the conventional system. Based on the analysis of the results, it can be concluded that the maximum benefit can be extracted from the hemispherical solar desalination if the reflectors’ angle is optimized and the top surface is covered with an insulator cover. The present work provides guidelines for optimizing the position of external reflectors. Further, the importance of the employment of insulation during energy retrieval is addressed.