Evaluation of efficiency of double slope solar still and drinking water yield using silver nanoparticle mixed with phase change material

This study shows the contribution of silver nanoparticles mixed with macro-encapsulated phase change material (PCM) in a double slope solar still. Experiments are carried out in three different depths and settings, first using simple double slope solar still, then by addition of PCM, and finally using PCM mixed with silver nanoparticles. Results obtained are compared during the sunshine period and also after sunset. The study shows that the silver nanoparticles in PCM results in reducing the yield and efficiency of the double slope solar still by 7.64% and 5.26% during the charging period. However, it continues to deliver potable water even after sunset due to the stored latent heat in the PCM. The higher thermal capacity of the PCM and the higher thermal conductivity of the silver nanoparticles resulted in a 16% increase in drinking water yield and a 62.53% rise in the thermal efficiency of the double slope solar still. The final cost per liter of the potable water generated using the double slope solar still was reduced to 3.80 INR and the payback time is 2 years which can be reduced further using PCM and nano-enhanced PCM inside the solar still.