Comparative analysis of double slope and pyramid top covers of passive type single basin solar stills with their thermo physical properties

Abstract

This work describes about the performance analysis of a passive type single basin solar still with two types of top covers such as Double Slope and Pyramid Top Covers. The performance parameters such as hourly yield, daily productivity and efficiency were calculated. The internal and external heat transfer modes and also the thermo physical properties such as dynamic viscosity, saturation pressure, thermal conductivity and latent heat of vaporization of basin water were calculated and compared for the two modes of the still. It has been observed that the effect of the cover tilt angle and the distance between the basin water surface and condensation surfaces influence the still productivity to an appropriate levels. The thermal conductivity of basin water, saturation pressure and the release or absorption of latent heat play vital role to improve still efficiency as well as overall productivity was analyzed. The above mentioned properties on comparison revealed that the still with double slope cover had more value than the still with this particular pyramid top cover. The average efficiency of the stills were calculated as 31% for pyramidal top cover is and 36% for double slope top cover. The total amount of distillate yield was obtained as 1200 ml/m² for the pyramidal still and 1350 ml/m² for the double slope still. The both efficiency and yield rate from this study also showed that the double slope still performed better than this particular Pyramid shaped still.