Model optimization and economic analysis of a multi-effect diffusion solar distiller

This study focused on finding the maximum productivity by optimizing vertical multi-effect diffusion solar distiller (VMED) and lowering the water cost of that. The numerical model of the VMED was experimentally validated, and then used to find the optimal conditions for the essential variables. The VMED consists of a glass cover, plates, wicks, and a seawater feeding unit. Each effect has a cotton-cloth wick attached to one side of the plate. This VMED repeatedly using condensation latent heat can get more production than that of conventional solar still. The numerical result showed that the optimum values of the gap distance of double glass cover and the number of effects were 25-30 mm and 10-15, and the feed flow rates of spring, summer, fall, and winter were optimal in 9, 16, 10, and 3 g/min, respectively in supplying same flow rate into all the effects. The maximum productions for all seasons (spring, summer, fall, and winter) were 16.6, 36.0, 19.0, 2.5 kg/(m(2).d), respectively in South Korea. Economic analysis showed that the potential water price of the VMED was 6.1 $/m(3), which was more competitive in the market than other solar desalination systems with a small capacity of < 100 m(3)/d.