Hybrid solar still – Liquid desiccant regenerator and water distillation system

Abstract

In 21st century, worlds’ major part is facing the challenges regarding requirement of comfort human condition as well as scarcity of potable water. The deficiency is utmost for hot and humid coastal areas. This leads to the evolution of system, which provides the solution for both sort of problems using low grade solar energy. In present study, hybrid solar still was developed with single slope for lower basin and double slope for upper basin. The performance of system was evaluated as regenerator for 33% concentrated Magnesium Chloride (MgCl2) as a pre-humidified weak liquid desiccant solution in upper basin. As a cogeneration system, lower basin was utilized as distillation system for brackish water having 0.10% concentrated Zinc Oxide (ZnO) nanoparticle with constant depth of 10 mm. ZnO nanoparticles was used to improve the heat transfer and optical characteristics of basefluid as nanoparticles have capability to enhance the thermo-physical properties. Experiment was carried out in month of March under humid climatic condition of location 20.61°N, 72.91°E. The results show that total amount of water desorbed from weak MgCl2 liquid desiccant was 1357.78 ml/m2 and distill water yield of 623.33 ml/m2. The theoretical model was developed for transient analysis and theoretical results were compared with experimental results. The theoretical concentration of regenerated strong liquid desiccant was 35.97%, whereas 34.89% concentration was obtained by Karl Fischer Titration. The hybrid solar still can provide latent cooling load of 0.161 kW/m2 with overall thermal efficiency of 19.20%.