Solar still; unrevealed facts and reasons causing its low productivity

The current techniques for water desalination are relatively costly because of the high consumption of electrical power or fossil fuel. desalination of seawater using solar energy is therefore,one of the ways to meet the growing water demand at low cost. with the technologies currently available,solar still fresh water production is not applied on large scales,mainly because the production rate of desalted water is very low,when compared with techniques using fossil fuels or membranes. the low production rate has been the main reason behind the lack of industrial usage of solar stills. as the maximum temperature,which can be reached within the solar still is not very high,the evaporation rate inside the solar still remains low. this low temperature is the main reason for such a massive disadvantage,resulting in a reduced heat transfer rate and slow vaporization process. the work reported herein aims at analyzing the reason(s) for solar still low productivity and suggesting design modifications to solve such a problem. this is done by dividing the solar still evaporation into four processes; then every process is thoroughly analyzed to solve the main problem,and provide the maximum temperature and heat transfer rate inside the solar still. with this problem solved,the use of solar stills in industry can become a possibility. © 2017,university of kuwait. all rights reserved.