Water Purification with Direct Solar Desalination for Arid Areas in Ethiopia

Abstract

The use of solar energy in thermal desalination processes is one of the most promising applications of in water purification. Solar desalination can either be direct; use solar energy to produce distillate directly in the solar collector, or indirect; combining conventional desalination techniques, such as vapor compression (VC) and multistage flash desalination (MSF), with solar collectors for heat generation. This paper describes a pilot study of direct desalination technology. The pilot experiment of desalination system was made up of a single basin (1.5m x 1.8m basin area) and two sided roof with 15 degree to the horizontal and sealed roof of 4 mm thick glasses. The glass cover roof was positioned from East to West orientation and obstruction free area to increase the efficiency of available sunlight utilization. Water quality parameters of the water and treated water were tested at Arba Minch University Water quality Laboratory. The study revealed that, the average yield of the distillate water was 2.6 L/m2/ day, where the average efficiency of the system was 29.5 %.
Regression analysis showed that climatic variables such as temperature, wind speed and solar intensity were observed to affect the treatment efficiency of the production of distilled water in this pilot study. Accordingly, the experiment output transposed to Dollo Ado, Somali Regional state and the solar still was predicted to produce 3.4 - 5 L/m2 /day with climate condition of the area. Although the system requires large area with relatively low production, it is still suitable for use in remote and arid with high temperature.