Experimental performance evaluation of a modified solar still integrated with a cooling system and external flat-plate reflectors

Abstract

This study was done to improve the productivity of an inclined solar still through some modifications include installing angle bars on the basin to increase the water residence time, fabricating the basin with adjustable inclination angle to achieve the highest amount of solar radiation in each season, installing top and bottom flat-plate external reflectors and a cooling system on the glass cover. The effect of the basin inclination angle, feeding water flow rate, cooling water flow on the glass cover, installing top and bottom reflectors at their optimum inclination angles on the productivity of the still were experimentally investigated under the climatic conditions of Tehran (35°N Latitude and 51°E Longitude) during summer, winter and spring. The results showed that in the case of applying only one modification, passing the cooling water on the glass cover has the most effect on productivity enhancement in spring while applying top reflector at its optimum inclination angle gave the best results in winter. Also, the maximum productivity of 4.2 kg/m2 was obtained for a basin inclined at 25° with top and bottom reflectors inclined at 10° and 45°, respectively. In this case, the feed water and cooling water flow rates were equal to 90 and 720 ml/min, respectively in solar radiation of 800 W/m2, air temperature of 22.5 °C, and wind velocity of 2.4 m/s. Moreover, the efficiency of the still was obtained as 36.7%, which was 14.2% higher than that of the still at an optimum inclination angle of 25° without reflectors and cooling water under the same weather conditions.