A Critical Review on Performance Enhancement of Passive Solar Stills Augmented with Phase Change Materials

Water is one of the most important life resources and potable water is a very precious resource. Clean water is one of the most important challenges in modern world and one of the key goals of sustainable development. Use of solar energy to generate clean water through solar stills is a cost effective and highly sustainable method. The only drawback of solar stills in generating clean distilled water is its low output. A number of methods have been tried to increase the distillate output of the solar still. Augmentation with Phase Change Materials (PCMs) is one of the popular methods for increasing the output of the solar still by storing the heat energy in the PCM when the solar insolation is abundant during the daytime. Once the solar insolation starts to reduce in the evening, the heat stored in the PCM helps in keeping the temperature of the solar still high and increases its evaporation capacity. The passive solar still does not require any external power for sustaining its operations and augmentation of such solar still with PCM provides an excellent way to increase the utilization of solar energy. This paper reviews the literature reported on outcome of augmentation of passive solar stills with PCM. The modelling and simulation efforts and experimental work are described with a point of view to identify the different methods of augmentation of passive solar stills with PCM and compare the effectiveness of these approaches in improving solar still performance.