Case Study of Improved Ship Energy Efficiency with Entropy Generation-Based Heat Utilization Efficiency Analysis Method

Decarbonization is a huge challenge for the entire world, as well as for shipping industry. Energy efficiency improvements are an important part of the GHG reductions, and new possibilities for this emerge especially in the field of waste heat recovery, once the industry is transferring into cleaner fuels in the future. This study presents a method and a case calculation where the entropy generation analysis is complementing the traditional energy balance analysis with minimal overlap. The developed method includes a definition of entropy generation-based heat utilization efficiency index. This index reveals the quality of heat, which the first law-based indicators fail to do. Various analysis methods, such as the heat utilization efficiency analysis, are an important element in development of the practical engineering tools for the design and optimization of the systems. The article presents three case ships for demonstrating the level of energy efficiency and their waste heat utilization efficiency. The studied ships include a RoPAX ferry, a cruise ship and a cargo ship for transporting liquid CO 2 . The case studies suggested 3-4% fuel saving potential with applied improvements in the machineries, but the heat utilization efficiency analysis suggested even further room for improvement. The example is restricted in this paper to the waste heat recovery and utilization in a ship environment, but the method is universal and can be extended to cover the full ship powerplant and all systems, if seen relevant for the researcher