Thermal analysis of a conical solar still performance: An experimental study

In this paper, an attempt is made to estimate the heat transfer coefficients of a conical solar still. Many researches and development works tried to enhance the productivity of solar stills using different methods. So in this study the productivity enhancement of solar still by decreasing the shadow effect and maximize utilization of solar radiation is discussed. A conical solar still was designed and manufactured at faculty of engineering Sheben El-Kom - Egypt (latitude 30.56 N and longitude 31.01 E). The still base area was 0.8 m(2), and the acrylic cover of still inclined at 31 degrees which equal to the city latitude. The experimental results of conical solar still were compared with a conventional type solar still which has the same area. The results showed that, the daily productivity for conical and conventional solar stills was 3.38 and 1.93 L/m(2) day, respectively. Heat and mass transfer coefficients were evaluated and the Nusselt and Sherwood numbers were calculated with the aid of both evaporation measurements and Chilton-Colburn analogy. The maximum value of the total heat transfer coefficient were 66 and 32 W/m(2) degrees C for conical and conventional solar stills, respectively. The analogy between heat and mass transfer coefficients was also investigated. (C) 2015 Elsevier Ltd. All rights reserved.