Experimental analysis of a four slope solar still augmented with a parabolic reflector array with V-shaped mirror arrangement for pre-heating brackish water

Abstract

For centuries long ground-water, the main source of fresh water for sustaining life, could be found in abundance on planet Earth. The scenario has changed drastically over the past few years as potable water has become a scarce commodity owing to the exponential growth in population. In such testing times man has been forced to look at sources other than ground-water for meeting his daily needs. Even though the yield of potable water obtained is less, desalination of hard water by means of a solar still is an economic method used for obtaining potable water using just the energy from sun. The current research explores the option of increasing the performance of a four slope still with wick by preheating the water before the start of evaporation and condensation cycle. Pre-heating was done using two methods; the first method involved passing brackish water inside Copper tubes and making the tubes pass through an array of parabolic reflectors. The second method involved coupling the parabolic reflector array with a v-shaped mirror arrangement through which Copper tubes were passed. Once preheated, the water was then fed to the four slope solar still for obtaining potable water. The influence of preheating water by the above said two methods on the yield from the still have been compared. The array of parabolic reflectors with mirror arrangement was found to increase the brackish water temperature by 8°when compared to the parabolic reflector array without mirrors. The water at elevated temperature which when fed to the still was found to augment the evaporation process and hence increased the productivity of the still by 10%, which amounts to more than 80 L a year. Hence, performance of a solar still can be improved by incorporating novel and viable solutions.