Computer modeling of passive/active solar stills by using inner glass temperature

Expressions for water and glass temperatures, hourly yield and instantaneous efficiency for both passive and active solar distillation systems have been derived. The analysis is based on the basic energy balance for both the systems. A computer model has been developed to predict the performance of the stills based on both the inner and the outer glass temperatures of the solar stills. In the present work two sets of values of C and n (C , n and C . ou,or) obtained from the experimental data of January 19,2001 and June 16, 2001 under Delhi cl~ati~"~onditi~, have been used. It is concluded that (i) there is a significant effect of operating temperature range on the internal heat transfer coefficients and (ii) by considering the inner glass cover temperature there is reasonable agreement between the experimental and predicted theoretical results.