Thermal analysis of a solar distillation system for ethanol-water solutions

The dimensions, volumetric flow rates, and thermal capacities of an ethanol distillation system where solar energy is used as primary energy are examined in this article. A rigorous thermodynamic equilibrium analysis is applied to obtain the critical design parameters for the solar distillation of an ethanol-water solution with different feed stream concentrations (5%, 7%, and 10% wt. ethanol) to obtain a distillate product of 95% wt. ethanol. The volumetric flow of the feed stream is varied and a sensitivity analysis is performed to study its impact on the design of the solar distillation system. Important technical details, such as the configuration of the solar distillation system, the size of the distillation columns, reboiler heat duty, energy consumption per unit mass of distillate product, solar fraction, and collector area, among others, are evaluated and presented as a guideline for designers. The methodology developed herein is used to design the solar ethanol distillation system and can be extended to other geographical locations, weather conditions, and operational parameters. (C) 2013 AIP Publishing LLC.