Improving solar still efficiency with nanoparticles – Infused copper cylinders and latent heat storage: An experimental and simulation study

Abstract

In the conducted experiment, a transformative change in heat transfer rate and productivity was observed when copper oxide nanoparticles were mixed with petroleum jelly and stored in a copper cylinder within the solar still. The heat transfer rate increased by 20 %, and the daily productivity of the system seen a significant improvement, with a 20 % increase compared to a phase change material (PCM) system and 40 % simple solar still (SS). The dispersed nanoparticle created a modified internal microstructure, forming a network or aggregate structure depending on their concentration and dispersion quality. This modified microstructure significantly improved the efficiency of heat transfer pathways, leading to 20 % faster heat transfer. The novel approach employed in this experiment distinguished itself from traditional solar stills and PCM based system. The exceptional thermal conductivity of the nanoparticles facilitated rapid absorption of solar radiation, resulting in increased energy input to the system and accelerated evaporation processes. The simulation result obtained using Comsol Multiphysics 5.6 indicated that even under solar radiation condition equivalent to zero, the temperature distribution of the nanoparticles enhanced phase change material based solar still system favourable, and heat transfer was efficient. Under zero solar radiation conditions, the phase change material with nanoparticle in solar still system (NPCM) exhibited a temperature 56.9 °C at 19.00 PM in the experimental condition and, in the simulation it has been found 56.1 °C respectively. The simulation results closely aligned with the experimental results. The daily productivity of the PCM and NPCM based homogeneous systems have been found to be 2945 and 4075 mL/m2-day higher, respectively, compared to simple solar still (SS) productivity 2120 mL/m2-day. Based on these experimental findings, it can be concluded that the NPCM system is more effective than the PCM based and simple solar still system. This can be attributed to the increased thermal conductivity, enhanced heat transfer rate, and improved evaporation rate achieved through the integration of copper oxide nanoparticles. Therefore, in regions with limited access to portable water, the NPCM system proves to be a highly useful and economically viable solution.