The Study Of The Performance Of The Solar Desalination System

At present, due to the uneven distribution of world water resources, most of countries are short of water in different levels. Meanwhile, there are also problems of unreasonable water exploitation and utilization, and the pollution of water quality. All the above water shortage problems make the water resources much more precious. In China, the situation is much severe because of the uneven distribution of the north and south water resources. Although the South-to-North Water Transfer Project has achieved some accomplishment, it can’t become a fundamental way to solve the problem for its excess costs. Desalinate seawater is one of the important way to generate fresh water for the plenty of seawater resources. However, the conventional desalination consumes electric energy and nowadays the fossil energy is also in shortage and the burning of fossil fuel will cause environmental pollution. Therefore, using new resources is the definite choice of seawater desalination technology. As one of the renewable energy, solar power has been wasted massively. In result, it can be a heat source for the seawater desalination.The desalination system with four-effect distillation powered by solar energy was analyzed in this paper. The mathematical models were developed to simulate dynamic changes, building quality and energy conservation equations for each effect, then making analysis of the system.Through theoretical analyze and experimental study, parameters on device operating can be gotten:when the temperature of hot water is higher than65℃, the system keeps a normal and continuous operation. Fresh water production and the outlet temperature of each effect increase with other parameters constant. The system can normally run in good condition when the last effect operating under the pressure of12kPa, fresh water yield is high. Fresh water production declines rapidly when the pressure is higher than17kPa. At the same time, In June, July and August when sunshine condition is better than other months, the amount of inlet water should be turned to200～250kg/h, hot water flow properly reduced to1000-1200kg/h, while the remainder the amount of inlet water and hot water can be reduced.Designing single effect horizontal tube falling film system, a further observation of influencing factors can be obtained.Finally, according to the actual situation, putting forward a cleaning solution feasible to the whole system, selecting wire mesh demister to make sure the water quality up to pharmaceutical water and devising solutions resisting sea breeze.