A CFD simulation analysis of the effects of PCM and nanoparticles stored in copper cylinders inside a solar still

Abstract

Solar stills, considered low-water production desalination systems, require scrutiny of various design and performance parameters to enhance productivity due to their modest yield. This research paper seeks to conduct a parametric analysis of a solar still desalination system and explore the impact of phase change material (PCM) and nanoparticles on the efficiency of a single-slope solar desalination unit. The investigation utilizes computational fluid dynamics (CFD) numerical simulation through the COMSOL Multiphysics 5.6 software. A simulation was conducted to evaluate the performance of simple solar still (SSS), solar still using phase change material (SSPCM), and solar still using phase change material with nanoparticles (SSNPCM). The PCM and NPCM are stored in copper cylinders for better heat transfer. The walls of the solar still were coated with black paint to enhance its ability to absorb maximum solar radiation, keeping its effective emissivity at 0.9. The effectiveness of the simulation was assessed by comparing the results with experimental data. In the SSNPCM system, the experimental evaluation revealed an evaporative heat transfer rate of 33.57 W/m2-K. Correspondingly, the simulation predicted a value of 32.05 W/m2-K. Additionally, the experimental and simulated results for conductive heat transfer were 2.7 W/m2-K and 2.2 W/m2-K, respectively. Similarly, for radiative heat transfer, the experimental and simulated values were 3.85 W/m2-K and 3.60 W/m2-K, respectively. These evaluations were completed at peak value, which is around 2:00 PM. The simulation model's dependability is demonstrated by the close agreement between the experimental and simulation results. Notably, the SSNPCM system demonstrated better performance in terms of radiative, conductive, and evaporative heat transfers than both the SSS and SSPCM systems. © 2024 Elsevier Ltd