A review of waste heat recovery from the marine engine with highly efficient bottoming power cycles

This paper aims at presenting an extensive review of waste heat recovery (WHR) from the marine engine with highly efficient bottoming power cycles which include the steam Rankine cycle, organic Rankine cycle, Kalina cycle and CO2-based power cycles. After detailed introductions and comparisons of the bottoming power cycles, the design and selection of system components are reviewed. An in-depth survey of the WHR systems operating under off-design conditions is then conducted, followed by a summary of technoeconomic evaluation. Finally, challenges and opportunities of integrating the WHR systems with other emission reduction technologies are discussed. According to the literature, trade-offs between working fluid characteristics, cycle configuration, size, cost and WHR potential should be made in designing an optimal bottoming power cycle, and fuel savings ranging from 4% to 15% can be expected. The payback time of installing a bottoming WHR system lies typically in the range from 3 to 8 years, depending on the fuel price, ship type, heat and power demands and component costs. The high-pressure exhaust gas recirculation technology is superior to other NOx reduction technologies due to its high potential of recovering waste heat from the high-temperature recirculated gas. Ship's operational profiles, engine tuning and slow steaming as well as other emission reduction technologies are recommended to be fully considered for future research on WHR systems.