Experimental evaluation of hybrid solar still using waste heat

Solar stills are cost-competitive compared to other renewable desalination technologies especially for very small-scale desalination devices. The commercialization of advanced solar stills, which can largely increase productivity, may require simpler design to increase their reliability and maintainability. In this paper, we have designed a multiple-effect diffusion (MED) hybrid solar still with simpler seawater feeding device and dual heat sources of solar thermal energy and waste heat. Performance tests with waste heat were performed with three operational parameters: the amount of heat inputted into the hybrid still, the seawater flow rate to the wick, and the seawater level in the basin. Experimental results show that the productivity of the hybrid still increases linearly with increasing heat input, recording 18.02 kg/m2 at 22.37 MJ/d. The maximum productivity of distillate was obtained at the lowest seawater level even in the case of the experiment with waste heat source. The maximum performance of the MED solar still is achieved at the operation condition obtaining maximum productivity at the second effect plate, indicating that the MED section of the hybrid solar still plays a more important role than the basin section in the entire performance of the hybrid still.