Performance study on solar still with enhanced condensation

Water scarcity and pollution pose critical situation in all walks of life especially in the developing countries. Among the available purification technologies, solar desalination process proves to be a suitable solution for resolving this existing crisis. This renewable energy technology operates on a basic principle of which the solar radiation enters through the glass surface inside a closed chamber touching the black surface generating heat energy, which gets trapped inside. This gradually raises the temperature of the liquid resulting in evaporation process and further condensation, which is drained out for use. In this connection, a basin type solar still (0.5 m(2)) with improved condensation technique was designed and built, and a performance study was carried out with different samples such as tap water, seawater and dairy industry effluent. The condensation occurs due to the temperature difference not only on the glass surface but also on the four sidewalls, which can be cooled by water circulation through tubes attached on the wall surface for efficiency enhancement. The maximum daily production of the solar still was about 1.4 L/m(2).d, and its efficiency was about 30%. The condensate water quality was analysed and compared with water quality standards, which was found to be comparable with rainwater and mineral water. Efficiency of the still was calculated for all the samples and compared with each other. The reasons for the findings and their implications for the design of the system are discussed. Some design features that would further enhance the thermal performance of the still were also identified from this present investigation and highlighted.