Productivity enhancement of a Double Slope Solar Still Utilizing Nano-enhanced Phase Change Material

Abstract

The influence of phase change material (PCM) mixed with nanoparticles at different concentrations (1%, 3%, and 5%) on the performance of a double-slope solar still has been explored experimentally in this work. The experimental apparatus is a basin-type solar still with magnesium heptahydrate as the PCM, impregnated with copper powder nanomaterial encapsulated in aluminium tubes located beneath the absorber plate. The experiments have been conducted in outdoor conditions from 10:00 to 17:00 hours with measurements recorded every hour for solar radiation, glass cover temperature, absorber plate temperature, basin water temperature, and distilled water output. Solar radiation is highest between 12:00 and 13:00 hours, which results in peak absorber plate and basin water temperatures. Without nano-enhanced PCM, extreme fluctuations in component temperatures are observed, whereas integrating PCM smoothes these oscillations by storing excess heat during peak times and releasing it subsequently. The heat-absorbing capacity of nano-enhanced PCM results in improved distilled water output. Among the cases tested, the PCM - 5% copper nanoparticle-based system yields the maximum of 750 ml, which is 48.5% more than the 505 ml yield of the conventional system. Increasing the nanoparticle concentration increases yield each time, especially at high solar intensity. The results reveal that PCM and nanoparticle hybridisation enhances thermal stability, latent heat storage capacity and remarkably increases freshwater yield, thus rendering the system efficient, stable, and viable for high diurnal temperature fluctuation.