Experimental investigation of a passive solar still with paraffin wax as latent heat storage

Purpose of present study is to investigate the performance of a single basin double slope solar still in conjunction with a thermal energy storage material: paraffin wax as a heat reservoir under the liner of the basin. The heat transfer coefficients are evaluated and their variations are studied. Furthermore, the constant C and n of the Nusselt's expression has been calculated. Overall 61% gain was recorded when PCM was used, where as a 34% nocturnal and 64% gain in the day time distillate was recorded. The daily experimental uncertainty was approximated to 16%. The water quality has shown a good agreement with the standards as proposed by WHO and BIS. In order to forecast the social acceptability, the economics of the still is also studied and it is found that such a still have a payback period of 4-5 months.