Winter and summer performance of single sloped basin type solar still integrated with extended porous fins

• Simple and economical modification for existing basin and deep basin type stills
• Better yield due to quicker start-up and higher operating temperatures
• Lesser base heat losses
• Nocturnal distillate output is also obtained.
• Highest 7.5 l/m2 output was obtained in the month of May.

A simple and economical modification for the basin type solar still is proposed. Porous fins made up of blackened old cotton rags were partially dipped in the basin water, while the rest of the part extended above the basin water surface. The extended part of the fins receives most of the solar radiation with minimum shading. The basin water is relatively cooler, thus causing lesser base heat loss. Early morning start-up and higher operating temperatures were reached, giving enhanced heat transfer coefficients and evaporation rate. The basin water primarily acts as a thermal storage which supplements the evaporation process during low insolation, besides giving a reasonable nocturnal output. 56% higher day time distillate and 48% higher for 24 h duration was obtained in the month of February over conventional still, whereas, in the month of May, 23% higher day time and15% higher for 24 h was achieved. A maximum distillate output of about 7.5 kg/m2 was achieved in the month of May in the case of the modified still made of expanded polystyrene foam with good insulation property. The distillate production increases with the decrease in the basin water depth. Experimental results are in fair agreement with that obtained by the thermal model. The modification can also be applied to deep basin type stills.