Experimental investigation of evaporation performances of a desalination prototype using the aero-evapo-condensation process

An experimental investigation was conducted with a desalination plant using the aero-evapo-condensation process. The present unit consists of a falling film evaporator and condenser made of polypropylene. It was designed to work at low temperatures (70-90 degrees C) and specially to use geothermal energy. The influence of the different thermal and hydrodynamic parameters on the unit performance was investigated. The results showed that the performance of the unit increases with inlet hot water and air temperatures. On the other hand, it was observed that the performance of the unit decreases when the air velocity and hot liquid flow rate increase. A critical film flow rate corresponding to the film breakdown was determined. At this value a maximum amount of evaporated water was obtained. Since the validation of any desalination plant needs an economic evaluation, the average cost of evaporated water was estimated. According to this result, the present process was compared to other desalination techniques. It was found that the energy required by the plant is relatively high. On the other hand, it was shown that in the arid and semi-arid areas, which have important resources of hot brackish water, the process is very interesting.