Interface Gradual Refrigeration Systems In Seawater Desalination Applications

Compared with the traditional sea water desalination, interface-progressing freezing sea water desalination is a new technology with small investment, low cost and energy consumption. The new technology can simplify the structure of the sea water desalination system, reduce the operation cost and achieve the purpose of fighting against global shortage of fresh water.The serious situation of fresh water shortage and several kinds of sea water desalination method are recommended. With the purpose of simplifying the structure of the sea water desalination system and reducing the operation cost, using efficient heat-pump technology, a new type interface-progressing freezing sea water desalination system is set up. Evaporator and condenser in closed cycle heat-pump system are combined together with interface-progressing freezing system and evaporator and condenser can be exchanged easily. The ice on the surface can be removed, and the cold let out during the ice melting process can be recycled, as a result, the cost during the process of sea water desalination is greatly reduced.The setting up process of the interface-progressing freezing sea water desalination system is detailly introduced. The reliability of the system is tested, and the freezing experiment of the sea water is carried out. The system is reliable according to the repeatable experimental data. Besides, with the increase of the ice on the surface of the tubes, COP, freezing and melting velocity all went through a progress from rapid-decreasing to slow-decreasing and then to rapid-decreasing. The COP of the system can be improved by increasing the density of the tubes, decreasing the thickness of the ice, or using finned tubes. The COP of the system also can be increased by using efficient compressor with low compression ratio. The cost of the water obtained is 7 yuan per ton and the saltness is 0.2%, which is competitive in the market. The study results and achievements have practical guiding significance, for the development and the upgrade works of freezing sea water desalination system.