Parametric studies on the transient performance of a hightemperature solar distillation system

A basin-type solar still integrated with an inverted absorber asymmetric line-axis solar compound parabolic concentrator (CPC) is presented as a potential option for high-temperature solar distillation. A simple transient analysis of the system was carried out. Explicit expressions were obtained for the water temperature, glass-cover temperature, water-to-glass-cover temperature differential, distillate output and efficiency of the system. Numerical calculations were made for quantitative assessment of the analytical results. Effects of several parameters, e.g., amount of water, absorptivity and the concentration ratio were studied in detail for the performance of the system. Owing to the heating of basin water from both top and bottom, water temperature rose significantly, accomplishing distillation of the brackish water at high temperature.

The analysis is simple and capable of satisfactorily illustrating behaviour of an inverted absorber asymmetric line-axis compound parabolic concentrating solar still. The system performed distillation at higher temperatures, which is usually accomplished by connecting a number of solar energy collectors to the basin of the still. Thus, this design offers a promising option for high-temperature solar distillation. So far, as the performance of the system is concerned, expected results were obtained, that is, the water temperature, glass cover temperature, water-to-glasscover temperature differential, productivity and efficiency increased with decreasing water mass in the basin. However, these parameters increased with increasing absorptivity of the basin liner and the concentration ratio. The bacteria contained in the brackish water were expected to be killed as the distillation was performed at a high temperature.