Experimental investigation of effect of using sand on the performance of solar still

Nowadays, population growth, pollution, climate change, depletion of groundwater resources and excessive water consumption are the main reasons for the shortage of fresh water. One of the methods for producing water is the use of solar energy, which is performed on devices called solar still. In this study, the effect of using different masses of sand on the production of double slope single basin solar still with a basin surface of 0.27 m^2 at a constant water depth of 1.5 cm on sunny winter days was investigated. The sand acts as a heat storage and when the solar radiation is low, the heat stored in it returns to the still. The findings of the research show that production in solar still without sand and solar still with a mass of 1 kg of sand is identical, also, with increasing sand mass, from 1 to 2 kg, the amount of still production decreases. On the other hand, the energy and exergy efficiency system have also decreased with increasing sand mass. As a result, putting 1 kg of sand in this solar still is as optimal amount and increasing it has a negative effect on system performance on sunny days.