Effect of energy storage medium (black granite gravel) on the performance of a solar still

Abstract

SUMMARYIn this study, a detailed experiment has been conducted on a single-basin solar still which is modified with energy storage medium of black granite gravel. An attempt has been made to utilize the maximum amount of solar energy and to reduce the heat loss from the sides and bottom of the still. The conventional still is modified with an energy storage medium of black granite gravel of 6 mm size which is provided in the basin for different (quantity) depths. The black granite gravel functions as energy storage medium and also as an insulation layer to reduce the bottom and side loss coefficients. The black gravel is used for absorbing the excess heat energy from solar radiation during the noon hours. Due to this, the heat accumulated in the space between the water and glass surface is reduced and hence the temperature difference between the water and glass surfaces increases. The depth (quantity) of the gravel layer in the basin will influence the performance of the still and some of the parameters like basin temperature, water temperature, glass temperature and still productivity. This study deals with the effect of aforesaid parameters on the performance of the still. An attempt has been made to optimize the still performance for the above-mentioned parameters. A mathematical model is developed to estimate the water, gravel, and inside glass temperatures theoretically and to estimate the hourly and daily yield. To show the effectiveness of the modification, its performance is compared with the conventional still under the same climatic condition. It is found that the still yield is increased by 17-20% with almost no cost for this modification as black granite gravel is very cheap. Error analysis was done by comparing the theoretical and experimental results to show the validity of the mathematical model. It is found that the maximum percentage of discrepancy for all the parameters is about AE 18%. Theoretical value of yield per day has 8% discrepancy over experimental value.

A comprehensive decade review and analysis on designs and performance parameters of passive solar still

“…The additional surfaces resulted in an increased evaporation rate by 53 % in comparison to the conventional single slope solar still. Sakthivel and Shanmugasundaram (2008) studied the effect of different quantity but of the same size (6 mm) black granite gravel as an energy storage medium on the performance (Suneesh et al 2014) of single basin solar still. System showed higher performance with large depth of storage medium.…”

Solar stills: A comprehensive review of designs, performance and material advances

“…The results showed that the double basin yields more distillate only when the water depth was maintained at just 1 cm [151]. This is inconsistent, however, with the results of Manivel et al [53] and Sakthivel et al [56] who achieved higher yield with 2.5 or 3 cm water depth. Hitesh (2013) conducted the experiment in a double-basin solar still with a vacuum tube ( fig 46) and black gravel granite attached to it.…”

Reviewson different energy absorbing materials for performance analysis of solar still

“…El-Sebaii et al [25] were used aluminu m, copper, stainless steel and mica plates as suspended absorbers material in single basin solar still during experiment.It was found that using metallic plates as suspended absorbers (Aluminu m, Copper and Stainless steel) the daily productivity of still about 15-20% higher than that of the conventional still. But it has problems of corrosion to use metallic plates as suspended absorbers.…”