In this communication an attempt has been made to find out distribution of solar radiation, using the concept of solar fraction inside a conventional (single slope) solar still by using AUTOCAD 2000 for a given solar azimuth and altitude angle and latitude, longitude of the place. Further the experimental validation of the model developed earlier has been carried out for design and climatic parameters. Numerical computations have been carried out for New Delhi climatic conditions (latitude 28degrees35' N, longitude 77degrees12' E). It has been observed that for given parameters, solar fraction can play a very important role at a lower value of the solar altitude angle.