“DESIGN AND MANUFACTURING OF A STEPPED-SLOPED SOLAR STILL INCORPORATED WITH PHASE CHANGE MATERIAL (PCM)”

Abstract

Commonly water sources contain harmful bacteria, minerals and organic impurities which make them unsuitable for drinking, irrigation and other purposes. Common process of desalination consumes large amount of energy to remove a portion of pure water from salt water. Solar still is the oldest method to convert saline and brackish water into fresh water using the unconventional source of energy which is freely and abundantly available on Earth i.e. Solar Energy. The solar still purifies water by first evaporating and then condensing it. The purified water contains no salts, minerals or organic impurities. In our Final year project, a stepped inclined solar still design is used to enhance the productivity of the conventional solar still design. The most important design parameters influencing the productivity are optimization of glass angle, absorber plate area, free surface area of water and depth of water. The stepped inclined still design is further modified by including sponges ( Baffles and wick effect), PCM ( 2 types of Paraffin wax for latent heat storage in order to provide low light functionality of the still), external reflectors (for concentration of solar radiation on to the still), insulation (for minimizing heat loss from the base of the still), k-type thermocouples(For monitoring the temperature at various locations within the still), and bubbling effect( Integrated with fans and an external condenser in order to maximize the rate of evaporation and thus the productivity). Complete dimensioning and 2D drawing of each and every part was done using AutoCAD. 3D modelling of the project was done using Autodesk inventor. MATLAB was used to conduct a detailed numerical analysis of the project in order to determine the effect of various modifications on the productivity of the still and the corresponding comparison graphs were plotted.