Performance Evaluation of Double Effect Solar Still

Development of different useful decentralised solar gadgets is possible due to the abundant solar thermal radiation available particularly in the western part of India. Desalination is one technique to use this energy to produce distilled water using solar stills. More so, even highly saline water can be treated using solar stills. The output of conventional basin type solar still is only 1-2 LPD. In this, the latent heat of condensation is transferred to the surrounding and wasted. To use the latent heat and enhance the output a double effect type of solar still with two basins is fabricated in this work. A cotton cloth is kept on top of the lower basin to make a thin-film layer of continuously flowing water. Hot water is supplied to the lower basin through solar flat plate collector. It is seen that with increasing salt concentration in feed water results in a reduction of product output from a conventional still, but, in the modified double effect still, the product output remains the same.