Effect of adding a passive condenser on solar still performance

Abstract A theoretical and experimental study was conducted to investigate the effect of adding a passive condenser on the performance of the single slope, basin type solar still. A theoretical model based on the Dunkle (Int. Devs Heat Transfer 5, 895 (1969); Ref. [1]) mass transfer (evaporation) rate was developed. The model assumes that the transfer of water vapour from the still to the condenser is due to one or more of the following mass transfer modes: (i) diffusion, (ii) purging, and (iii) natural circulation. The theoretical results indicate that the diffusion contribution is relatively small. The contribution through purging represents the fraction [condenser volume/(condenser volume + still volume)] of the still yield. About 75% of the still yield is contributed through natural circulation. An experimental study that simulates the purging mass transfer mode was investigated. The experimental results show good agreement with the theoretical predictions and an increase of 50% in the still efficiency.