Experimental studies on solar multi - effect sea water desalination system

A multi - effect desalination (MED) system with a capacity of 10 m3 has been designed, fabricated, erected and experimented to convert sea water into potable water using solar energy. Steam is flashed initially in the flash chamber of the desalination plant, using hot water from a solar flat plate collector field and is fed to the first stage of the multi-effect evaporator. The average hot water temperature realised from the collector field is 75°C. In the multi-stage evaporator, sea water is sprayed parallelly to vacuum pressure to produce water vapour and simultaneously condense the water vapour flashing through the tube from the flash chamber / previous effects. The brine and condensate is carried to the last stage of the multi-effect desalination (MED) system by utilizing monometric head. It is observed that during the experimentation, the maximum temperature difference between inlet and outlet of the condenser cooling water is 13°C. The ejector is used to maintain the vacuum pressure during the operation of MED system including flash chamber. Experimental studies on the MED system is carried out to understand the performance as well as thermal behaviour of the system using exclusively solar energy.