Comparative Energy and Exergy Analysis of Various Passive Solar Distillation Systems

Abstract

In this communication, a comparative energy and exergy analysis of various conventional solar distillation systems has been presented. The study includes passive solar distillation systems such as single and double slope solar stills. In a single slope solar still category, three solar stills with inclination angles 15o, 30o and 45o and a 15o inclined single slope multi wick solar still have been considered. Whereas one double slope solar stills and one double slope multi wick solar still, both inclined at 15o with east-west orientation, have been considered in double slope solar still category. The embodied energy is an important factor which depends on locally available materials and their manufacturing technologies. Materials like concrete, wood, steel etc are considered to calculate the embodied energy for the solar still equivalent to the fibre reinforced plastic after deriving the formulae. It has been found that the energy, exergy and embodied energy of single slope solar still are found higher than that of double slope solar still. Those materials which have lower thermal conductivity and low embodied energy than that of FRP such as concrete, PVC, wood can replace the FRP to save the embodied energy for similar performance. The metals have high embodied energy hence these can not be considered in terms of embodied energy despite the use of insulation.