Experimental Study and Performance Analysis of Phase Change Material Integrated Stepped Slope Solar Still

The major challenge in developing countries is to provide drinking water to the people, several techniques are employed but the challenge is to make cost effective and its sustainability over a period. Most of the developing countries work on saline water conversion to neat drinking water, distillation is one of the old and handy techniques in this conversion; where sunlight is used as energy drive for the process because elevating the temperature of saline water is enough for distillation and also for its free of cost availability. Solar still distilled water costs very less than the conventional method of deriving water from saline water and also people need not to worry about the purification of obtained water. Hence various analysis on increasing the performance of solar stills is required to increase the productivity to meet the rising demand for clean drinking water. The experimental work is carried out with three stepped solar stills, one without phase change material, one with paraffin wax as phase change material and other with calcium nitrate as phase change material. Solar stills are integrated with phase change materials to increase the productivity of clean drinking water by storing the solar energy in the form of latent heat to release in the dark hours for enabling solar sill distillation even during night time. There will be change in the total productivity based on the size of solar still, phase change material used, basin design and exergy efficiency, therefore these parameters have to optimized for better yield of neat drinking water from saline water. Experimentation was carried in the month of February and March of 2020 to estimate and compare the yield of three solar stills for the time period of 24 hours, certainly solar stills equipped with phase change materials resulted in higher total production than solar still without phase change material though their day time productivity was low. Solar still equipped with calcium nitrate as phase change material yielded 8.17 % more clean drinking water than the solar still equipped with paraffin as phase change material, though calcium nitrate is economical than paraffin wax but maintenance of solar still with calcium nitrate as phase change material is a hefty task.