Field test of a solar seawater desalination unit with triple-effect falling film regeneration in northern China

Based on the mechanism of falling film evaporation condensation, a new four-stage distillation unit with triple-effect regeneration has been designed, constructed and field tested. The seawater desalination system is driven by 80m² all-glass vacuum tube solar collection system with an additional 1kW wind power system to provide electricity for pumps. The field testing and monitoring of the system had been carried out under the real weather condition for 2 years. The results show that the water production of the system for per unit of solar collector area could reach up to more than 12kg/m²/day under the fine weather conditions. Water production of the system was stable in long period and the annual production could reach to 250tons in northern China. The economic performance of the system is also discussed. The cost of water production is estimated approximately 4.6Dollar/ton for the 15-year service life.