A low-temperature multi-effect desalination system powered by the cooling water of a diesel engine

This paper introduces a medium-size low-temperature multi-effect desalination (LT-MED) system. Powered by the cooling water of a 1000 kW diesel power generator set, the system can produce 60 tons of fresh water per day. First, the thermodynamic and heat transfer model of the LT-MED system is derived. Second, an integrated four-effect tower distiller is designed and built. The system is installed in the Guishan Island, Zhuhai, Guangdong, China, and tested comprehensively. In the operation, the evaporation temperature of each effect is linearly proportional to the heat load of the power generator. Additionally, the evaporation temperature in each effect distiller rose linearly when the heat load was gradually increased. The variation of evaporation pressure was consistent with the evaporation temperature. When the heat load of the power generator increases from 300 kW to 530 kW, the fresh water production rate increases from 1.26 m3/h to 2.30 m3/h. The conductivity of the fresh water is usually < 100 μS/cm. Because of electricity and freshwater co-production, the system is environmental friendly and is particularly useful for islands and offshore platforms.