An easy to use user interface in the Windows environment using Borland Delphi has also been underdeveloped. It is aimed at providing the users with a friendly environment for the selection of different simulation options. The simulation may be achieved through a selection of different options, including different modes of the still, weather data, design or simulation options and other input variables. The output window summarises the simulated performance of the solar still and the heat-exchangers, and this data can be viewed in separate files. Some of the interface windows are shown in Figures 1 and 2. The current user interface is operational and has very basic features. To upgrade the interface, several in-built functions and graphical display features may be easily incorporated in the future.