FEASIBILITY STUDY OF HARVESTING WATER FROM ATMOSPHERIC AIR

Fresh water demand is increasing globally and numerous research is being carried out to develop efficient technology for harvesting water from atmospheric air. This paper highlights water harvesting experiments from atmospheric air by using CaCl2 desiccants and as well as heat pump method. Experimental studies showed that water vapor attraction capacity of LiBr, LiCl and CaCl2 desiccants were relatively higher than of Silica Gel, Molecular sieve or Activated Carbon. Experiment with 35% solution of CaCl2,using solar heat for desorption of water vapor, yielded 15 ml of water in 24 hrs at an average humidity of 65%. When auxiliary heat from electrical source was applied for desorption of water vapor from CaCl2 solution, 10 ml of water was harvested in 4 hrs at an average humidity of 65%. Experiment using gas compression method to condense water vapor from air generated 300ml of water in 6 hrs at an average humidity of 63%.