Performance enhancement of basin solar still using paraffin wax and floating wicks in the basin

Abstract

Single effect basin type solar still has been modified to enhance the productivity of still by placing paraffin wax and floating wicks in the basin. The paraffin wax was used to store solar energy during daytime and the same energy was supplied to basin water during night to generate distillate during night. Whereas, the floating wicks were placed in the basin to enhance the evaporation rate of basin water of modified still during day time. Initially, the performance of modified still has been compared with conventional still to find the effect of paraffin wax under the similar weather and operating conditions. The effects of covering basin area of the still with paraffin wax at fixed basin water depth on the distillate output of solar still have been investigated. The modified still performed better, when basin area of the still was partially covered with paraffin wax because of availability of path for heat transfer and energy storage between warm basin water and top surface of wax during night. It has been observed that the cumulative efficiency of still was found to be maximum when 6000 g of paraffin wax was placed in the basin water and solar intensity was 23.5 MJ/m2. The overall distillate of modified still with paraffin wax in the basin was recorded as 3.96 kg/m2 which was 28.14% higher than the conventional still. The overall cumulative efficiency of modified still having paraffin wax in the basin and conventional still was 72.63% and 56.67% respectively when the solar intensity and ambient temperature was 23.5 MJ/m2 and 34.8 °C. When floating wicks were added with paraffin wax it gives the higher overall productivity gain which was 31.36% more that of conventional still. The overall cumulative efficiency of modified and conventional still was 80.69% and 61.42% respectively.