Developing a waste heat recovery tube used in the seawater distillation system

•Developing a system to utilize ICE waste heat to distill fresh water from seawater.•Fin structures are tested to propose a high heat transfer efficiency structure.•The heat recovery efficiency can reach up to 40% in most engine operating modes.•The system heat efficiency can be improved by about 12% of total input energy. Designing and manufacturing a combined system that utilizes the thermal energy of coolant and exhaust gases from Internal Combustion Engines (ICE) to distill fresh water from seawater on Vietnamese offshore fishing vessels is an education ministry-level project that the research team is working on. Utilizing this heat sources not only improve heat efficiency, but also provide fresh water on equipped vehicles. The experimental process shows that, the heat energy emission changes consecutively according to the ICE modes, directly affects the performance of the heat recovery equipment as well as the performance of the system. The content of this paper will present the process of designing a waste heat recovery tube by assessing the effect of heat exchanger structure in exhaust heat recovery equipment to the heat transfer efficiency between exhaust gases and sea water. The studies were conducted on Ansys Fluent software, in which the input data was determined from experimental data. The research results depict that the exhaust heat recovery efficiency is highly dependent on the heat exchanger fins structure. With a reasonable format, the heat recovery efficiency can reach up to 40% in most engine operating modes which lead to an improvement of approximately 12% of the total input energy.