In order to measure various internal heat transfer processes, namely convective and evaporative in a solar still, an indoor simulation experiment has been carried out over a typical operating temperature range. The condensing surface was maintained at three different environmental conditions: (a) by exposing it to ambient air temperature, (b) by exposing it to air conditioned surroundings, and (c) by keeping ice on the condensing surface. The temperature-dependent physical properties of enclosed vapour were considered. The constants (C and n) for the convective heat transfer coefficient were determined by using linear regression analysis. It was observed that the proposed model gives closure results with the experimental observation within an accuracy of 8%.