Water desalination using solar continuous humidification–dehumidification process using hygroscopic solutions and rotating belt

Abstract

In this study, solar energy is utilized for providing fresh water by purification of tab water using rotating belt utilizing the addition of hygroscopic solutions containing kaolin or calcium chloride. The function of the hygroscopic solution is to increase the surface area and thus the percentage of evaporation on the rotating belt. It was shown that the use of hygroscopic material enhances the production of fresh water to a significant level. Additionally, the use of kaolin has been shown to be superior to the use of calcium chloride. The use of kaolin in the proposed solar desalination device has increased solar desalination from 10.8 kg/m2·day of using pure tap water to 32.1 kg/m2·day. A mathematical model was established to the use of hygroscopic material in this solar desalination using rotating belt. It was found that the maximum system efficiency was 61% after utilizing kaolinite; approximately seven times more comparing to the efficiency without using kaolinite (8.7%).