Waste heat recovery of a marine diesel engine using humidification – dehumidification desalination

In this study, in order to waste heat recovery from a marine diesel engine, a humidification – dehumidification desalination unit type of open – water and closed – air cycles with water heated is proposed for producing the consumed fresh water the crew of the ships. The energy required to produce freshwater is provided by recovered heat from exhaust gases from marine diesel engine. For this proposed system, first simulated thermodynamically and detailed energy and exergy analysis, in order to determine the main sources of irreversibility and performance characteristics of the system is conducted. Moreover, a comprehensive parametric study to find key parameters trend with system performance parameters is carried out. The study found that the system has the ability to produce 0.2746 kg.s-1 fresh water, using 432 kW of primary energy. As well as desalination efficiency and exergy efficiency were calculated to be 1.516 and 23.9%, respectively. And from an exergy analysis it can be seen that among all the components of the system, the heater has the highest exergy destruction rate, which accounts for about 73.2% of the total exergy destruction rate.