Parametric study on a vertical multiple-effect diffusion-type solar still coupled with a heat-pipe solar collector

A parametric investigation was theoretically performed for the vertical multiple-effect diffusion-type solar still, which consists of a number of vertical partitions in contact with saline-soaked wicks with narrow gaps between the partitions, coupled with a heat-pipe solar collector. The proposed still has some advantages: the still’s size is compact, the still can produce distilled water without electricity, and the productivity is greater than that of conventional multiple-effect diffusion-type solar stills. We theoretically predicted the optimum angle of the solar collector on the spring and autumn equinox and the summer and winter solstice days, and also performed parametric investigations of the design and operation conditions; it was found that productivity increased with an increase in the number of partitions and the temperature of the saline water fed to the wicks, and with a decrease in the ratio of the solar collector area to each partition area, the thickness of the diffusion gaps between partitions, and the feeding rate of saline water to the wicks.

We theoretically performed a parametric investigation of a vertical multiple-effect diffusiontype solar still, coupled with a heat-pipe solar collector. The results of this work are summarized as follows: 1. The optimum angles of the solar collector of the proposed still are equal to the solar altitude angle at southing on the spring and autumn equinox and winter solstice days, and 10° on the summer solstice day. The optimum angle is 26° when the solar collector angle is fixed for the year if the proposed still is used at 26°N latitude. 2. The overall daily productivity is 9% or 17% larger for the optimum solar collector angle stills than the fixed one on the summer or winter solstices. 3. The productivity increases with an increase in each partition area and the number of partitions, and a decrease in the feed rate of saline water to the wicks.