Phase change materials (PCMs) for improving solar still productivity: a review

This paper comprehensively reviews the use of phase change materials (PCMs) as latent heat storage systems to improve the productivity of solar stills. Previous studies on enhancing the productivity of active and passive solar stills with PCM are also presented. These studies show that a passive solar still with PCM shows a productivity improvement of up to 120% compared with a solar still without PCM. Meanwhile, the productivity improvement of an active solar still with PCM could reach as high as 700%. These results indicate that productivity increases along with an increasing PCM mass and a decreasing saline water mass. The PCM is also observed to be less effective in daytime than in night-time. It is also shown that organic PCMs (such as paraffin) were mostly used in studies on productivity improvement, whilst very few studies have examined the effects of inorganic and eutectic types of PCM.